Cemented Stems, Impaction Grafting, and Cement in Cement Revision

 

 

 

 

INDICATIONS AND CONTRAINDICATIONS

The increase in the number of primary total hip replacements (THRs) in an aging population has led to an increase in the number of revisions (1). Revision and rerevision THRs are associated with increased complications and decrease survivorship compared with primary THR (2). Some of these complications are related to the difficulty in removing prosthetic femoral components and the decreased bone stock often encountered at the time of revision (3).

Reconstruction of the femur at revision surgery can be performed successfully using both cementless and cemented fixation. Although faster to implant and having good long-term results reported (4), cementless revision stems are associated with several issues that include the risk of intraoperative fracture; postoperative stem subsidence; thigh pain; stress shielding; the need for revision in case of postoperative fractures around loose stems; the need for a transfemoral osteotomy and the need to often deal with extensive bone loss from removing distally fixed stems; and the reliance on increasingly distal fixation and longer stems at each revision. In contrast, cemented stems, and in particular cemented polished stems, can potentially overcome these issues. First, revision could be avoided in case of periprosthetic fractures around some loose stems (5). Secondly, when revision is unavoidable, they provide a number of revision options that are matched to the age of the patient and extent of femoral bone damage. Cemented polished stems offer the ability to revise a well-fixed stem through a minor cement in cement revision, greatly simplifying the revision (6,7). Cemented polished tapered stems also offer the ability to revise and reconstruct complex proximal femoral deficiencies through the technique of impaction bone grafting and still use a standard-length stem without compromising survivorship (8,9). These techniques are particularly important as they don't affect future revisions should the need arise (10,11,12,13,14,15).

When confronted with the need for a stem revision, our indications and preferences are as follows:

1. Cement in cement revision is performed whenever possible.

   If cement in cement exchange is not possible because the cement-bone interface is not adequate, there is too much proximal femoral destruction that precludes this, or a cementless stem is being revised, then:

2. if the patient's life expectancy is more than 15 years, revision is performed in conjunction with impaction bone grafting or

3. if the patient's life expectancy is less than 15 years, a revision with a cement-alone long-length cemented polished stem is performed

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We reserve the use of cementless stem fixation for severe proximal femoral deficiencies that are not reconstructable and for patient conditions and age which will put them at an unacceptable risk when subjected to a lengthy procedure.

Cement in Cement

Removal of well-fixed cement during femoral stem revision prolongs operative time, increases blood loss, and may require a transfemoral approach. Further, it damages the femoral bone and predisposes to femoral fracture and femoral cortex perforation. In contrast, a new femoral stem can be cemented into the original cement mantle provided the mantle is largely intact and still has good fixation in bone. Importantly, cement in cement revision usually allows revision with a standardlength stem.

This technique is indicated in cases of:

 

Aseptic loosening at the stem cement interface

 

Recurrent dislocation due to stem malposition and malrotation or to compensate for cup malposition in difficult cup revisions

 

 

To avoid cup revision in cases of severe acetabular bone loss, where the cup is currently stable To adjust leg length and stem anteversion after difficult cup revisions for severe bone loss

 

Leg length discrepancy

 

Fractured stem in a stable distal cement mantle

 

Some Vancouver B2 periprosthetic fractures around cemented polished stems (16)

The cemented polished stem design has potential advantages in cement in cement revision (14). First, its shape favors easy stem removal from an old mantle at the time of revision, even when the prosthesis is well fixed. Second, the taper-slip principle of controlled subsidence (17) optimizes fixation with cement and then compresses the cement mantle radially, transmitting compressive load to bone, and minimizes shear at the cement-bone interface.

When performing cement in cement revision, all cement that is not firmly fixed to the host bone is removed. This is tested by passing a scalpel into the cement-bone interface. While cement in cement revision can offer an elegant solution to a number of revision situations, once there is excessive mantle disruption, proximal bone loss, or fracture, it is no longer feasible. In this situation, the defective area needs to be either bypassed or reconstructed. Although currently no limits have firmly been established, for young and active patients, we perform standard stem length cement in cement revisions when the residual cement mantle was not removed below the level of the lesser trochanter. In older and less active patients, cement in cement revision is undertaken even if the cement was removed in some areas below the lesser trochanter.

Femoral Impaction Bone Grafting

Femoral impaction bone grafting is a technique that allows femoral revision to a standard or only slightly longer femoral stem in most cases or to achieve a stable long stem revision in the presence of severe bone loss when distal cementless fixation is not possible. It is ideal for any young and middle-aged patients undergoing revision of a cementless stem or a cemented stem not suitable for cement in cement exchange. In both human and animal studies, femoral impaction bone grafting has been shown to reconstitute bone

(18). Younger patients are likely to require further revision surgery during their lifetime, and therefore, avoiding the need for long stems in order to achieve femoral fixation will be very beneficial at subsequent revisions. Femoral impaction bone grafting aims to both preserve and restore bone for effective stem fixation at femoral stem revision. In addition, preserving the femoral diaphysis will be beneficial if the patient requires a total knee replacement or a revision total knee replacement in the ipsilateral limb.

Femoral impaction bone grafting and a cemented polished stem have several indications especially in patients likely to undergo further revision surgery in their lifetime. Indications include the following:

 

Femoral canals with cavitatory bone loss.

 

Femoral canals with segmental bone loss, which can be contained by metal mesh prior to impaction grafting.

 

A sclerotic femoral canal, even in the absence of severe cavitatory or segmental bone loss. For example, we frequently use impaction bone grafting at the second stage of a two-stage revision for treatment of an infected hip replacement.

 

Internal femoral bone loss preventing distal cementless fixation.

Contraindications for femoral impaction grafting are:

 

Severe circumferential proximal cortical femoral bone deficiency and no supporting rim of bone to contain the bone graft with mesh—an indication for modular cementless fixation.

 

 

 

Hips with comminuted or difficult periprosthetic fractures and associated bone deficiency. In these cases, cementless distal fixation is a useful option, but when distal fixation cannot be achieved, femoral impaction grafting with a long stem and additional plate and mesh support remains an alternative before moving to a total femoral replacement.

The rationale for using a cemented polished stem in the primary replacement and cement-alone revision scenarios also applies in femoral impaction bone grafting when a stable impacted bone bed supports the cemented stem. These stems, which have more than 40 years of clinical use in primary THR, have thus been the stem of choice for revision surgeons using impaction grafting techniques (9,19). The combination of a collarless prosthesis with a highly polished surface and double taper wedge allows the prosthesis to slightly subside within the cement mantle to achieve a strong, self-locking construct. The self-limiting subsidence also acts to transmit compressive load to the implant bed, which is purported to aid in bone remodeling and fixation. The technique has evolved over more than 15 years with the aim of improving early implant stability and bone graft incorporation. This includes better instrumentation design with modular tamps. The modular system allows the surgeon first to concentrate on reconstruction of the distal femur, then to establish leg length, and finally to separately address proximal impaction and mesh reconstruction, if required, providing a more user-friendly and effective method of packing the allograft distally and proximally. The method of graft preparation has also been refined to improve its properties and may include removal of fat by washing, size profiling of the bone particles, and the use of nonirradiated bone graft.

Cement-alone Long Stem Revision

The early experience with femoral revisions was associated with high rates of complications, failures, and rerevision for both cemented and cementless stems. For cemented stems, these results were attributed to poor cementing, use of standard length stems, poor stem design, and failure of the acetabular component. By contrast, more recently good results have been reported for both cement-alone and cementless stem revisions. For cement-alone stem revisions, the good results are mainly associated with cemented polished stems and attributed to improved cement techniques and the use of long stems.

The main factors that influence our decision whether to use a cement-alone revision or in conjunction with impaction bone grafting are related to patient age, life expectancy, activity level, and severity of the proximal femoral deficiency. As a general rule, we use a cement-alone long stem revision in patients aged over 75.

 

The indications for femoral revision THR with a cement-alone long stem revision are Aseptic loosening, including osteolysis

 

Periprosthetic fractures

 

 

Conversion of previous excision arthroplasty Recurrent dislocation

 

Infection

 

Rarely, unexplained pain

This technique can be routinely used in elderly patients with severe proximal femoral deficiencies (80% of our patients being classified Paprosky Grade IIIA or worse (20)) within 2.5 cm below the lesser trochanter and up to 5 cm in elderly low-demand patients, without any other proximal femoral reconstruction.

Advantages of using cemented fixation of long stems at revision include the following:

 

Immediate fixation allowing rapid full weight bearing and early rehabilitation. This is particularly valuable in patients who do not cope well with partial weight bearing.

 

The procedure is simplified by using the stem and cement combination as a customized construct that fits the damaged femur exactly while aiming for a stem position that approximates the axial alignment of the femur without the need to be absolutely midline in both planes.

 

This system is forgiving of femoral deformity and can be used to fit femoral deficiency and deformity without aggressive bone removal, extended trochanteric, or other corrective osteotomies.

 

Cemented fixation minimizes the risk of periprosthetic fracture because no impaction of the stem is necessary.

 

Cement fixation eliminates the need for reaming of bone to fit a stem.

 

Cement fixation is along the whole of the stem, so the construct can accommodate some proximal bone loss, provided there is still adequate proximal bone support for the stem.

 

Cemented polished stems keep more future revision options open, allowing for easy stem removal from the cement mantle for a cement in cement exchange in cases of rerevision for instability or infection.

 

Leg length can be easily modified based on the trial reduction and is continuously variable at the time of implantation.

 

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There is minimal risk of stem fracture because an inherently strong forged stem is used.

 

This stem design is also relatively low cost especially in comparison with cementless revision systems as it is approximately ⅓ to ¼ of the cost of a monoblock or modular cementless stem, even when including all disposables.

 

Long cemented polished stems can be divided into two types: Stems that have a continuous taper from proximal to distal.

 

Stems that have an intermediate part in the middle of the stem that is either a different taper or, in some

designs, a cylindrical portion. These stems are longer and are commonly used for cement-alone stem revisions and have the advantage of a easier fit within a curved and deformed femur.

 

PREOPERATIVE PREPARATION

Examination and Evaluation

The preoperative examination is thorough and needs to include assessment of gait, Trendelenburg test, neurologic and vascular status of the lower limb, assessment of power, range of movement, and measurement of real leg length discrepancy. Particular attention should be given to hip abduction and flexion and palpation of the glutei to ensure the muscles are functional. As some patients may have undergone multiple operations and been incapacitated for some time before they reach revision, significant muscle wasting and weakness are not uncommon. Subjective and objective preoperative evaluation of pain and function are important for reporting outcomes.

Radiography

Preoperative radiographic evaluation of the femoral component and femur is undertaken using an AP pelvic radiograph centered on the midline halfway between the symphysis and a line crossing the anterior superior iliac spines and a long leg anteroposterior hip and lateral/oblique hip radiograph showing the whole of the femur down to the supracondylar region. Some surgeons also argue for the role of CT scanning to understand complex multilevel defects and MRI, especially when soft tissue damage, particularly of the abductors, is known or anticipated.

Preoperative Planning

Careful preoperative planning is required and vital to the success of all revision THR. A good approach is to plan the most appropriate reconstruction for the individual patient, but have alternative plans in place and other choices available intraoperatively:

 

 

Establish the strategy for removing the old femoral stem and the need, size, and position of a femoral osteotomy if necessary to facilitate this.

 

Template the acetabular component first to establish the hip center and then the femoral component.

 

Template the femur (Fig. 26-1) for stem length, size, offset, depth of insertion, plug site, extent of bone grafting, and proximal reconstruction, but be prepared to modify according to intraoperative findings.

 

Clearly delineate areas of major osteolysis, stress risers, femoral perforations, and points of diaphyseal angulation or malrotation; all of these influence the size and length of the stem required.

 

The template selected is one that fits the proximal femur, leaving room for cement. The femoral template is aligned so that it is centered in the diaphysis and then the template is moved so that the center of the femoral head and shoulder of the stem are appropriately positioned to restore the planned amount of leg length.

Aligning the femoral template in the canal will reveal incongruities such as excessive bowing or angulation in the AP or lateral planes. After identifying the planned center of rotation on the radiograph and the proper position of the femoral component, the optimal head position and stem offset is determined. Limb length is predicted based on the hip center and the height of the calcar and lesser trochanter, in conjunction with clinical measurement and preoperative radiographs. It may be necessary to use the unaffected side to template from as well in severe disease to understand and restore the native hip geometry.

An important advantage of the cemented polished stem is that it can be continuously adjusted proximally and distally to obtain the required leg length. Both during templating and intraoperatively,

 

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aim to achieve leg length without using the longer heads, which have a skirt. These are reserved for situations where an unplanned increase in leg length is required.

 

 

 

FIGURE 26-1 Preoperative templating using radiographic films and implant specific templates. In summary:

 

Measure the height of the center of rotation and implant shoulder height relative to the tip of the greater

trochanter, or other lateral landmark.

 

Identify potential difficulties in implant removal and insertion.

 

Plan the level and type of femoral or trochanteric osteotomy and the bed for its reattachment.

The need for proximal reconstruction and the extent of bone graft required should also be determined.

 

FEMORAL EXPOSURE TECHNIQUE

Anesthesia and Draping

We prefer anesthesia by epidural catheter, often supplemented by a general anesthetic, and large volume long-acting local anesthetic infiltration in all patients.

Patients are placed in the lateral position with the pelvis perpendicular to the operating table with the back parallel with the posterior margin of the table and the opposite hip flexed. Anterior and posterior pelvic supports are used to stabilize the pelvis. A foam pad is placed between the knees and taped in place to allow knees and ankles to be palpated for leg length determination. Small foam pads are used to cushion the underlying fibula head and lateral malleolus. Preparation and draping is along standard lines with dyed alcoholic chlorhexidine paint used to prepare the whole leg from the malleoli to nipple line and across the midline, with the groin being painted last. The prepped area should be allowed to dry and pooling on drapes avoided. A large drape is placed over the contralateral leg to the groin and another over the trunk above the iliac crest. A U-drape is used to shut off the perineum but permit maximal posterior access and leaving the iliac crest exposed. The leg is bagged and then wrapped with crepe bandage to just above the knee. Large paper or plastic disposable hip drapes are placed over the thorax. At this stage, the pre-existing scar can be marked with a sterile pen. An iodized transparent adhesive drape is folded double under the thigh closing off the groin and a large iodized drape over, closing off all exposed skin.

Access should be available from above the iliac crest to the distal femur. The outer gloves are changed at this

stage before starting incision. With the heels together, the positions of the flexed knees are compared as a guide to leg length.

 

 

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Approach

Expose the hip joint using your approach of choice. For revision surgery, an extensible exposure is

recommended, especially in difficult revision cases. We would strongly recommend a posterior approach, with or without a trochanteric slide or an extended trochanteric (transfemoral) approach. A straight distal skin incision is performed, centered over the greater trochanter, curving slightly posterior and proximally towards the midpoint between the posterior superior iliac spine and iliac tuberosity, along the anterior border of gluteus maximus.

Particular attention during exposure should be paid to the following key points:

 

 

Successful revision surgery is reliant on maintaining good abductor function. Take time to clearly identify the gluteus medius muscle and tendon. The simplest way is to find the anterior margin of gluteus maximus and develop the plane between gluteus medius and gluteus maximus from anterior to posterior, eventually identifying clearly the posterior margin of gluteus medius. This ensures the abductors will always be protected (21), whereas simply dividing gluteus maximus in the line of its fibers can cause devastating and irreparable damage to medius in the common revision scenario where medius is adherent to maximus with scar tissue.

 

Unless performing a transfemoral approach, we would always advise dividing the tendinous insertion of gluteus maximus from the femur during revision surgery to facilitate exposure. While doing this and while dividing the short external rotators, we place the foot on a padded, draped Mayo table so that the femur drops into early internal rotation allowing the sciatic nerve to fall away from the area of dissection.

 

The sciatic nerve is identified in almost all cases, and having been visualized, or at least palpated, its course is checked to make sure it is clear of the dissection. This does not require full exposure but at least palpation of the nerve course.

 

In general, stay on bone during dissection. Use cutting diathermy frequently throughout the procedure.

 

Determine Leg Length

Prior to dislocating the hip, obtain a baseline measurement of leg length using your preferred method. We recommend measuring from a pin in the ilium or ischium to a diathermy mark at the vastus ridge.

Remove Femoral Component

After sufficient soft tissue dissection and release, carefully dislocate the hip and remove the femoral component. We routinely apply a cerclage wire to the proximal femur at this stage to protect the often fragile proximal femur. To protect the proximal femur during implantation of the acetabular component, any femoral cement is left in the femur to be removed following completion of the acetabular side even when not aiming for cement in cement exchange.

The femoral component is, ideally, removed without an osteotomy, as this converts a cavitatory defect into a cortical defect, with an associated increased risk of complications and a significant problem if union is not successful. Removal is simplified by aggressively clearing any overhanging medial bone at the greater trochanter. Sometimes, further exposure is required for removal of the existing stem, especially if the stem is uncemented with a fixation surface extending distally; in these cases, we prefer a transfemoral approach. This is reduced and fixed with cables prior to preparing for impaction bone grafting or a cement-alone long stem. In case of impaction bone grafting, we prefer to additionally stabilize a femoral osteotomy with the use a longer stem.

Revise the Acetabular Component

Following removal of existing implants, insert the new acetabular component. Note the new center of hip rotation.

 

CEMENT IN CEMENT TECHNIQUE (SEE VIDEO 26-1)

Once adequate exposure of the proximal femur is obtained:

 

 

A cerclage wire is passed prophylactically around the proximal femur—to prevent any inadvertent fracture, and all remaining soft tissue covering the stem, cement, and bone-cement interface is removed with a burr (Fig.

26-2).

 

Stem version and position of shoulder in relation to greater trochanter are noted for further reference regarding final anteversion (Fig. 26-3A) and leg length.

 

 

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FIGURE 26-2 Stages of cement in cement revision. A: Remove all proximal cement restricting stem extraction, paying particular attention to the shoulder of the stem. B: Apply a protective cerclage wire around the proximal

femur prior to extracting the stem. C: Extract the stem using an implant-specific or universal (illustrated here) stem extractor. D: Retained intact clean cement mantle. E: Refashion the existing cement mantle with a burr to allow for the desired new implant size, seating, and rotation in the old cement mantle. F: Revised stem.

 

 

A burr is used to remove all cement and bone overhanging the shoulder of the stem that is to be removed (Fig. 26-2A).

 

Stability of the implant composite is tested at both stem-cement and cement-bone interface.

 

The femoral head is removed, a universal stem extractor is applied to the neck of the stem, and the stem is removed using the slap hammer of the universal stem extractor (Fig. 26-2C).

 

All loose proximal cement is removed using the burr.

 

 

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FIGURE 26-3 Intraoperative assessment of implant version is based on the long axis of the leg with the knee bent at 90 degrees. A: Version of the initial implant. B: Trial implant version. This was deemed insufficient, and further refashioning of the cement mantle was performed. C: Trial implant version after the desired new

version was achieved. D: Version of the revised implant.

 

 

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FIGURE 26-4 Various sizes of trial implants.

 

 

The remainder of the cement mantle is burred according to the need for the cement in cement fixation and also for any change in stem size and version (Fig. 26-2E).

 

Trial implants (Fig. 26-4) are used for a trial reduction to estimate leg length, version, offset, stability, and impingement (Fig. 26-3B, C). The desired position of the stem shoulder and version are noted.

 

The femoral canal is thoroughly washed and dried using suction through a pediatric feeding tube.

 

Two packets of antibiotic PMMA bone cement, which contains tobramycin and to which we add 0.5 g of vancomycin powder for each 40-g packet of cement, are loaded into a cement cartridge, which can be fitted with a narrow nozzle.

 

The new stem is cemented in the same way as any other primary stem with the exception that a wingless or no centralizer is used; that depending on the amount of proximal femoral canal exposed limited pressurization can be achieved; and that the stem is introduced in the runnier cement phase.

 

FEMORAL IMPACTION GRAFTING TECHNIQUE

Preparation of Bone Graft

Fresh frozen nonirradiated femoral heads are used to prepare various size bone chips. Usually at least three femoral heads should be available, although more may be needed in cases requiring long stems or with severe bone loss. Allograft bone should be obtained only from a recognized bone bank, and it is helpful if the supply is local should more be needed intraoperatively. A sterile bone mill is used to create bone chips from the femoral heads intraoperatively, if this has not been prepared preoperatively. Alternatively, commercially available prepacked bone chips can be used, but these are much more expensive.

Soft tissue and articular cartilage are first removed from the femoral heads, while preserving subchondral bone. The ideal size of bone chips ranges from less than 1 mm up to 4 mm for intramedullary impaction. Approximately half a femoral head should be divided with a saw into 5 mm × 5 mm × 5 mm and 5 mm × 5 mm × 10-mm cancellous cubes for packing into the proximal femur at the osteotomy level. To remove fatty marrow, the bone chips are washed several times in saline heated to 45°C and then strained over a 200-μm strainer or a pack.

Antibiotic powder, 0.5 g of vancomycin/femoral head, is added.

Femoral Impaction Grafting Instruments

We use cemented polished stems and have available the primary hip, revision hip, and impaction grafting instrument sets.

The impaction grafting set includes the following:

 

 

Distal femoral packers, which are cannulated larger diameter rods used initially to pack the distal allograft area (Fig. 26-5A).

 

Corers, which are designed to remove excessive graft or cylindrical plugs of graft up to 7 cm long. These are used for complicated cases and when longer stems are indicated (Fig. 26-5B).

 

Modular tamps for primary standard-length stems and for longer stems (Fig. 26-5D). Each tamp assembly consists of a proximal tamp, a distal tamp, and a locking screw or locking rod and a

 

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gliding rods that connects the two. The tamp assembly is initially used as a monoblock tamp using the locking screw or rod, then as a modular tamp for proximal impaction and finally as a monoblock tamp, to remove the tamp for cement and stem insertion. While the locking screw and locking rod perform the same function, the locking rod is longer to facilitate its application and tightening when access to the proximal tamp is difficult (Fig. 26-5E).

 

 

 

FIGURE 26-5 Instrumentation for impaction bone grafting. A: Distal packers. B: Corers. C: Packers. D: Range of modular tamps. E: Gliding rod, locking rod, and locking screw used to connect the modular tamps.

 

The sets also include

 

 

The appropriate size prostheses

 

A medullary bone plug together with a long wire that is threaded into the plug to guide the packers, corers, and tamps (shown later in Fig. 26-7B)

 

Standard bone cement accessories

 

A narrow or tapered cement nozzle and a supply of reconstruction meshes, cerclage wires, and cables

 

 

 

Impaction Grafting Technique (See Video 26-2)

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Using the acronym derived for a cemented polished taper (CPT) stem, a 3 Cs, 3 Ps, and 3 Ts technique was developed as an intraoperative guide for femoral impaction grafting.

The 3 Cs

C1. Cerclage wire proximally.

C2. Contain distal cortical defects.

C3. Choose stem length and leg length using the largest rasp as a trial component and mark a bone reference point that is opposite to the shoulder of the trial rasp.

 

The 3 Ps

P1. Plug the canal, with guide wire attached to plug or drill guide wire into retained cement. P2. Plan tamp size and packer sizes to fit the femur by passing over guide wire.

P3. Pack allograft distally.

 

The 3 Ts

T1. Tamp with monoblock tamp. If necessary, add mesh proximally to contain allograft and then remove guide wire.

T2. Trial reduction to check length, offset, and stability.

T3. Tamp with modularized tamp to maximally impact proximal femur.

 

Details of the Impaction Bone Grafting Technique

C1. Cerclage Wire Proximally Protects the proximal femur from fracture during implant removal and during impaction. A wire may be preferable to a cable in the proximal region, adjacent to the joint.

C2. Contain Distal Cortical Defects The femur is then inspected for cortical defects. Distal defects must be contained with mesh and cerclage wire or cable.

C3. Choose Stem Length and Determine Leg Length Choose a stem that extends to twice the femoral diameter beyond the most distal cortical defect. Determine leg length using largest rasp as a trial. Mark the bone reference point opposite the shoulder of the trial rasp (Fig. 26-6A). This mark is also used as the mark for the distal insertion of the tamp (Fig. 26-6B). Determination of optimal stem length is based on the extent of bone loss assessed from preoperative radiographs and intraoperative assessment. In the absence of distal defects, a standard stem with or without mesh is most often used. A long stem is recommended if major distal cortical deficiencies are present after preparation. We recommend that the stem should also extend beyond distal wires or cables applied around a femur with thin cortices because these may act as a stress raiser unless a strut graft or plate is applied. We also recommend that a longer than standard stem should be used if a trochanteric slide or osteotomy is necessary or there is a major proximal deficiency, as the rotational stability of the impaction grafting is somewhat lessened.

 

 

 

FIGURE 26-6 The position of the shoulder of the rasp (and implant) is established by performing a trial reduction using a head and neck provisional. This position is marked on the greater trochanter. Hip provisional implant in reduced (A) and dislocated position (B).

 

 

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P1. Plug the Canal with Guide Wire Attached or Drill Guide Wire into Retained Cement Thread the guide wire onto the bone plug and slide the starter packer over the guide wire (Fig. 26-7A). Insert the bone plug to the appropriate canal restrictor depth mark on the packer. If a distal bone pedestal or retained cement is used as a plug, drill the guide wire using the packers to centralize. Remember that the restrictor must be 4 cm, and two cortical femoral diameters, below the most distal defect as the medullary canal restrictor should be 2 cm below the tip of the distal tamp, which is approximately 2 cm longer than the corresponding stem. The medullary canal sizers are used to determine the size of the canal restrictor that will be stable at the appropriate canal restrictor depth. Place the guide wire into the medullary bone plug and slide the starter packer over the guide wire. Gently tap the distal femoral packer and canal restrictor to the selected distal bone plug site, and check that the bone plug is stable (Fig. 26-7B).

P2. Plan Tamp Size and Packer Size Plan tamp size and packer sizes to fit the femur. Choose the largest tamp assembly that achieves correct version and varus/valgus position and leaves a minimum 2 mm between the tamp and bone to allow for a bone graft and a cement mantle of appropriate thickness. The tamp assemblies are equivalent in size to the implant of the same number plus an allowance for a relatively thick cement mantle. The tamp should be well lateralized.

P3. Pack Allograft Distally (Figs. 26-7 and 26-8) The safe insertion depth for each distal femoral packer is determined. Begin with the 10-mm distal femoral packer inserted over the guide wire. Then, sequentially increase the packer size and record the largest distal femoral packer size that can be inserted to the depth of the bone plug without impinging on the canal wall. This is designated the “starter packer” and will be the first distal femoral packer used to impact the distal allograft. Using the starter packer inserted over the guide wire, pack graft distally. Sequentially add graft between packing. Continue packing distal graft until the “distal pack” mark on the distal femoral packer is level with the

 

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bone reference point (Fig. 26-8). Sequentially larger diameter distal femoral packers can be used as more allograft is added if the femoral canal flares considerably above the intended bone plug site. The extent of grafting and the distal bone plug site should be chosen with the following considerations:

 

 

 

FIGURE 26-7 Distal impaction graft. A: The canal restrictor is inserted coupled with a guide wire used to centralize the impaction grafting instruments. The canal restrictor guide wire couple is inserted with the largest distal packer that fits the femoral canal at the location of the canal restrictor. B: Canal restrictor—guide wire couple inserted at the adequate location for the stem length planned. C: First bone graft is packed using the distal packers. D: Each distal packer is marked such that the packer is advanced only to the desired/adequate depth in the femoral canal. E: This level, the distal pack line, corresponds to the level of the shoulder of the rasp/tamp/implant established during trial reduction (Fig. 26-6). (Courtesy of Zimmer Pty Ltd.)

 

 

 

FIGURE 26-8 Intraoperative images of distal graft packing. A: Canal restrictor mounted on guide wire in initial packer. B: Detail of depth marking on distal packer for a 130-mm stem. (Courtesy of Zimmer Pty Ltd.) C: Adding graft to canal. D: Packing graft. E: Inserting distal corer. F: Cutting distal core.

 

 

Impact 10 mL of graft initially to enhance the bone plug fixation (Fig. 26-8C).

 

 

Then, continue to introduce 5 mL at a time of morselized allograft into the femoral canal around the guide wire. Adding too much graft at one time may cause a void in the graft.

 

 

Pass the starter packer over the guide wire and pack the bone graft distally firmly by hand. Do not use a hammer. Remove the starter packer and introduce another 5 mL of graft.

 

Then, reintroduce the starter packer and pack the graft again.

 

 

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For long stems, after using the distal femoral packers, use the graft corer over the guide wire to remove a central core of the impacted distal graft (Fig. 26-8E). The graft corers can remove a cylindrical plug 10 mm or 12 mm in

diameter and up to 7 cm long. The corers can be used in two different ways, either to remove bone graft that may inadvertently become trapped in the distal canal during tamping with standard-length stems or routinely to remove distal graft during long stem impaction grafting. Insert the corer to the level of the graft, and, while applying pressure, turn the T-handle to penetrate the impacted graft (Fig. 26-8F). Then, without twisting the T-handle, withdraw the corer to remove the graft core.

T1. Tamp with Monoblock Tamp (Fig. 26-9) Hand pack graft with the selected tamp. Use the packer to introduce graft distally. Alternately add graft and tamp until the entire canal is lined circumferentially with impacted graft. Check anteversion each time. Impact until the shoulder

 

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of the starter tamp is level with the bone reference point. Continue graft insertion and tamping until graft fills the femur, the tamp is stable, and desired final tamp size is reached (if tamp size is decreased to allow for a bigger allograft mantle).

 

 

 

 

FIGURE 26-9 Intraoperative images of tamping graft over a guide wire. A: Graft is added in 5-mL portions. B:

Sequential tamping. C: Bone graft is positioned using small packers. D: Proximal femoral bone deficiencies are

assessed and contained with wire mesh stabilized with cerclage wires (E). F: Before the locking screw connecting the two tamp components is replaced by a gliding rod, for proximal impaction, a trial reduction is performed.

 

Eventually, the femoral canal is solidly and evenly packed with allograft and the tamp assembly has initial stability. If proximal bone reconstruction is required, such as the use of mesh to contain the graft proximally, leave the tamp in place to act as a guide. Apply medial mesh so the graft is contained up to the neck cut mark. If a trochanteric slide or osteotomy has been undertaken, the lateral deficiency can be restored in its distal part by using a lateral mesh and the trochanter reattached after the stem has been cemented. Mould the mesh around any residual lesser trochanter or, if preferred, trim the lesser trochanter with a saw. To anchor the mesh, a wire is preferable to cable in the proximal region, adjacent to the joint (Fig. 26-9).

T2. Trial Reduction to Check Length, Offset, and Stability At this stage, perform a trial reduction using a cone and femoral head provisional to check leg length and prosthesis offset and stability. For trial reduction, first, remove the tamp handle and guide wire. Attach the appropriate cone provisional to the trunnion of the tamp and a femoral head provisional. Perform a trial reduction to check leg length and offset (Fig. 26-9F).

 

 

 

 

FIGURE 26-10 Proximal impaction grafting. After trial reduction and confirmation of leg length, offset, and stability, the locking screw is removed (A) and replaced with a gliding rod (B). C: Proximal impaction grafting is performed with the tamp in the modular “mode.” D: Diagram of proximal tamping. (Courtesy of Zimmer Pty Ltd.) E: The impaction grafting is finalized by insertion of bone “croutons.” F: The newly created femoral canal. G: After stem implantation showing cement protecting the graft.

 

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T3. Tamp with Modularized Tamp to Maximally Impact Proximal Femur (Fig. 26-10) Proximal graft impaction is done using a using a modularized tamp. Disassemble the final tamp (Fig. 26-10A). Thread the guide rod extension through the proximal tamp and into the distal tamp (Fig. 26-10B). Attach the tamp handle and partly withdraw the proximal tamp and pack 5 mL of allograft around the proximal tamp by hand with the proximal packers. Impact the graft with a mallet by impacting the proximal tamp down to reach the distal tamp (Fig. 26-10D). Withdraw the proximal tamp approximately 1 cm, and use the proximal packers to impact cancellous cubes (5 mm × 5 mm × 5 mm and/or 5 mm × 5 mm × 10 mm) and smaller allograft pieces (Fig. 26-10E). This will create a stable, reconstituted bone mantle at the osteotomy level. Continue alternating graft insertion and proximal tamp impaction until the proximal canal is evenly and solidly packed with allograft. An indication of adequate impaction is a torque of at least 50 inches/pound. The proximal and distal tamps in situ are then reconnected. This is done by removing the guide rod extension and inserting the locking rod through the proximal tamp and then tightening this into the distal tamp with the screw driver. The tamp should be at the appropriate depth as determined during the trial reduction. The tamp assembly is then tapped out by approximately 1 cm and gently reseated by hand so it can be easily withdrawn immediately prior to cementing.

Following the procedures covered by the 3 Cs, 3 Ps, and 3 Ts, the next stage is cement insertion and stem insertion.

Cement and Stem Insertion (Fig. 26-11) Prior to cementing, insert a thin suction tube down the guide wire hole in the tamp to remove blood. For standard stems and long stems, use a cement gun with a narrow or special tapered nozzle for impaction grafting that has been cut to the length of the stem. This facilitates cement injection into the narrow distal stem area. For larger long stems or any stem where the 12-mm graft corer has been used down to near the distal part of the cement mantle, a standard cement nozzle can be used to deliver cement to the canal. Immediately before cement insertion, carefully remove the tamp from the neomedullary canal. If the bone graft at the femoral neck is no more than a few mms thick and well supported by bone, plan to use the pressurizer seal as one does for a primary cemented stem (Fig. 26-11). If the bone graft is thicker

 

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and has required a mesh for support, it may be disturbed by the pressurizer seal, so apply an inverted cement restrictor plate to the top of the cement and inject the cement through this. Fill the canal with cement in a retrograde fashion without disturbing the impacted bone graft. When the canal is full, break off the cement nozzle, apply the pressurizer seal to the cement gun, leave the inverted plate on the top of the cement if used, and inject additional cement, forcing the cement into the allograft and maintaining pressure until the cement reaches a slightly less doughy state than in primary stem cementing. For femoral impaction grafting with a cemented polished stem, the wingless revision distal centralizer should be used (Fig. 26-11). This wingless centralizer is not packaged with the stem but is available as an individual sterile package. If only a winged distal centralizer is available, remove the wings with bone nibblers to prevent disruption of the graft as the stem is inserted. Attach the centralizer to the femoral stem with a twisting motion. Place a thumb or finger over the medial femoral neck while inserting the stem to maintain cement pressure and to ensure that the stem does not move into varus. Insert the stem in three continuous stages as we recommend for all stem insertions. First, advance the stem into the cement mantle to half way and use this to judge the consistency of the cement and ease of insertion. Proceed to insert at a normal, faster, or slower rate depending on this initial insertion. The stem inserter has a mark center line along its center line midsection to align the stem. Next, check anteversion while advancing the stem to within a centimeter of the final position as determined by the mark on the bone and the neck cut and marks on the stem. Finally, slowly seat the stem while the cement becomes increasingly viscous so the stem is rotationally stable at final insertion. Stabilize the stem with one hand while removing the inserter with the other. Gently push a small amount of cement over the lateral shoulder of the stem. This is recommended to

prevent the remote possibility that the stem will back out inadvertently should a postoperative dislocation require reduction. A small amount of cement may also be left over the proximal graft so that the graft is contained and not affected by lavage of the hip at the end of the case. Gently remove excess cement. If not already applied, place the polymer proximal restrictor around the proximal body of the stem to apply pressure and contain the cement during polymerization (Fig. 26-11). Once the cement has hardened, the femoral head provisional is used to confirm final femoral neck length to optimize stability. Undertake a final assessment of the leg length, range of motion, stability, and abductor tension.

 

 

 

 

FIGURE 26-11 Cement and implant insertion. The cement is inserted in a retrograde fashion using a cement gun (A); then, it is pressurized (B). The stem with a wingless centralizer in inserted (C). A “horse collar” cement restrictor helps cement infiltrate the graft during the curing phase of the cement (D).

 

CEMENTED LONG STEM FEMORAL REVISION TECHNIQUE

Special attention should be paid to the degree of bowing or deformity in the femur with long stem implants as this may prevent insertion or lead to perforation.

Femoral Canal Preparation

Ensure sufficient bone removal at the greater trochanter (by using a gouge, rongeurs, rasps, or a power burr) to allow good access to the femoral canal and axial rasping. This will enhance axial alignment, preventing varus malpositioning, and is a key part of the preparation of the femur. While rasping laterally, protect the gluteus medius tendon from damage using a curved retractor. Cement should be removed using a combination of hand tools, distally controlled drills or burrs, and ultrasonic tools. Either endoscopic instruments or sterile illuminated wands are useful to visually inspect the canal. Urologic catheter inserters can also be useful to feel for cortical perforations, and on occasion, fluoroscopy can be valuable.

Distal cortical defects should be exposed. In case of a cement-alone long stem revision, the defects are bone

grafted with mesh support after cementing the stem. One technique is to apply a mesh with wires temporarily over a dam made of a swab enclosed in a finger from a surgical glove, then graft this area when the cement has set and then apply the definitive mesh. The femoral canal is usually a mixture of predominantly sclerotic bone and some residual cancellous bone. However, on occasion, there may be an internal neocortex that can be removed with a burr or rongeur to expose underlying cancellous bone. In addition, the lesser and greater trochanters often have a neocortex that can be removed to aid in cement interdigitation. To help cement interdigitation, make horizontal grooves in thick areas of the endocortex (Fig. 26-12).

Rasping by hand alone is preferred, but if a mallet is used, the rasp should be advanced with moderate taps of the mallet only. Antevert the rasps by approximately 10 to 20 degrees. Then, sequentially rasp until the rasp is gently seated, stable, and at an appropriate level. Leave the rasp in place, and mount provisional components to obtain the best size, offset, and neck length of the stem. Ideally aim to seat the rasp to the osteotomy level, thereby achieving a minimum 2 to 3 mm of cement mantle thickness throughout, although in revisions, this may be compromised somewhat, depending on the shape of the damaged femur. The forgiving nature of the cemented polished stem in cement is ideally suited for these indications.

 

 

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FIGURE 26-12 Any sclerotic endocortex is burred to increase cement interdigitation and impregnation.

 

Trial Reduction

The ability to adjust leg length and offset at the time of the trial reduction is a distinctive feature of the trial reduction for cemented polished stems. With the rasp in place, apply the provisional neck and head and then perform a trial reduction. If the rasps or provisional are unstable, use surgical swabs or packs as necessary to stabilize the rasp or provisional in the canal, preventing rotation. Similarly, if it is desired to seat the stem slightly proud, insert a trial locating pin into the appropriate hole to maintain the proud position during the trial reduction (Fig. 26-13).

 

 

Perform a trial reduction, and, if necessary, adjust the provisional components to optimize joint stability, leg length, and range of motion. Aim for a neutral head center to avoid the need for a skirted head. Observe the relationship of the center of the femoral head to the top of the greater trochanter and compare to the preoperative plan.

When there is a minor calcar deficiency, use the larger body 200-mm or longer stems. When there is a major calcar deficiency, a valgus necked revision stem may offer a solution, as it allows the stem to be sunk further without compromising the leg length (Fig. 26-14).

Check the sciatic nerve tension and range of motion, confirm positions of potential instability, confirm that the

preoperative goal for leg length has been achieved by using the preferred method of measurement (Fig. 26-15A), and mark the shoulder of the rasp (Fig. 26-15B). After performing the trial reduction, remove the rasp and provisional components.

 

 

 

 

FIGURE 26-13 Use of the locator pin to maintain the trial in a proud position.

 

 

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FIGURE 26-14 Comparing valgus and conventional neck options.

 

 

 

FIGURE 26-15 A: The distance between a pin in the ilium and a mark on the proximal femur during trial reduction is compared with that recorded before the implants were removed. B: Marking the position of the shoulder of the rasp on the greater trochanter.

 

Cement Introduction

Plug the distal canal, insert cement in a retrograde manner, and pressurize cement until the desired viscosity is achieved. Medullary canal sizers are used to determine the appropriate core size for the medullary canal restrictor. The medullary canal plug is inserted to the mark on the inserter that corresponds to approximately 2.5 cm or 4 cm below the tip of the stem for cement-alone revision or impaction bone grafting, respectively. The inserter is positioned laterally in the femur in the same

 

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orientation of the midline of the stem. Introduce the restrictor with gentle hammering. If the site of the plug will be below the isthmus, a second plug is inserted over the initial plug if the initial plug is unstable (Fig. 26-16). To do this, a larger plug, with some of its core having been removed with bone nibblers, is inserted. Otherwise, use a small amount of cement or insert a temporary stout Kirschner wire through the femur at the site below the plug to support the plug. Once the femoral canal is prepared, remove any loose bone, fat, and blood. One technique for this is to use a femoral brush followed by pulsatile lavage, insertion of a thin plastic suction tube, and subsequent femoral packing. The pack may be presoaked in a variety of fluids to minimize bleeding such as hydrogen peroxide.

 

 

 

FIGURE 26-16 A large canal occluded by multiple plugs.

 

For cement-alone long stem revision, four packets of antibiotic PMMA bone cement, which contains tobramycin and to which we add 0.5 g of vancomycin powder for each 40-g packet of cement, are prepared and loaded in two cement cartridges. The bone cement is introduced in a relatively low-viscosity state at approximately 2 to 3 minutes. The cement is injected into the canal in a retrograde fashion, and a femoral pressurizer seal is used to seal the cement proximally while pressurizing the cement for a few minutes.

Implantation

Assemble the stem to its inserter, and then attach the distal centralizer. The stem is slowly advanced into the cement mantle, while maintaining appropriate anteversion and aiming for anatomical axial alignment. While inserting the stem, a valuable technique is for the surgeon to put his or her thumb posteromedially at the entry point to prevent varus alignment. The surgeon should aim for a minimum 4 mm of cement on the medial side of the stem but should be prepared to compromise the position somewhat so that the stem fits approximately down the middle of the cement.

After inserting the stem to the final position, the stem is stabilized with one hand while the inserter is removed with the other. It is recommended to gently push a small amount of cement over the lateral shoulder of the stem so that stem within cement subsidence may be evaluated on plain radiographs. This also helps prevent the remote possibility of the stem backing out inadvertently should a postoperative dislocation require reduction.

Apply a polymer collar cement seal to maintain pressurization and stem position until the cement hardens. Once the cement has hardened, a further trial reduction is performed and appropriate head size selected. Ensure that the neck taper is clean and dry. Place the femoral head on the taper with a twisting motion until it locks on the taper. Place a pack or swab over the femoral head to protect it and then seat the femoral head with a few gentle blows using a femoral head impactor and mallet. Protect the femoral head with a gauze pack and hold it away from the acetabulum to avoid inadvertent impingement. Then, clean the acetabulum and reduce the joint always while using the operating surgeon's fingers to protect the posterior structures containing the sciatic nerve.

Remove the gauze from the femoral head as the head is reduced.

 

WOUND CLOSURE

After obtaining hemostasis, insert a wound drainage device, if desired. Then, close the wound in layers; it is the authors' preferred technique to use soluble sutures for skin closure, reinforced with skin glue. These are then covered with a gas semipermeable transparent adhesive membrane dressing. This means that the wound can be easily reviewed without removing the dressing. Also, the primary theater dressing can be left in place for 14 days and then removed by the patient.

PEARLS AND PITFALLS

 

In all cases, successfully removing the stem without excessive proximal femoral destruction is a primary

objective. The two key points to this are (a) adequate clearance of the lateral shoulder of the implant that permits the implant to be extracted smoothly along its axis and (b) the routine placement of a proximal femoral cerclage wire as soon as it is practical, unless performing a transfemoral approach. This will reduce the risk of proximal cracks and propagation of existing ones.

 

 

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A stout K wire inserted across the femoral canal will prevent the canal restrictor from migrating distally when the stem length determines that the position of the canal restrictor needs to be distal to the isthmus where the femoral diaphysis expands.

 

Cement in Cement

 

Cement-in-cement revision can offer an elegant efficient solution in well-chosen patients.

 

Ensure sufficient preparation of the old cement mantle to (a) avoid retained cement debonded from host bone and (b) room within the old cement mantle for the desired orientation and leg length for the new stem.

 

Impaction Bone Grating

 

Ensure good direct access to the femoral canal along the anatomical axis by lateral reaming and preparation of the greater trochanter.

 

Use washed nonirradiated allograft bone, because of its potentially superior mechanical and biologic properties.

 

Use a bone mill that can produce a gradient of chip sizes.

 

 

Compound modular tamps produce a much more even graft, especially proximally. Use cut down 10-mL syringes to load graft.

 

Ensure that the long wire used to centralize the packers, corers, and tamps is well fixed into the distal bone restrictor and is not accidentally dislodged during the procedure before being voluntarily removed. The most at-risk step to dislodge a wire “less ideally” connected to the distal bone restrictor is when using the corers.

 

In case of segmental proximal femoral deficiencies, use preformed strong proximal mesh that will contribute to a more stable proximal grafting and therefore rotational stability of the implant.

 

Cement-alone Long Stem Revision

 

Ensure good direct access to the femoral canal along the anatomical axis by lateral reaming and preparation of the greater trochanter.

 

Use 200-mm or longer stems, which have a thick proximal body, unless there is a very thin femoral canal. It is not necessary for the distal stem to fully fill the canal.

 

Bypass distal diaphyseal cortical defects in order to reduce the risk of periprosthetic fracture.

 

POSTOPERATIVE MANAGEMENT

In postoperative recovery room, AP and lateral radiographs are taken to confirm that the articulation is located and there are no cortical breaches, when a cement-alone long stem is used. Standard follow-up radiographs are then taken when the patient is comfortable and has good leg control, on day 4 postoperatively. Patients are mobilized with full weight bearing within 24 hours. Hip restrictions will in part be dictated by the approach and extent of dissection.

The surgeons' preferred method of thromboembolism prophylaxis should be employed.

Antibiotic prophylaxis is administered; continuing antibiotic treatment is not administered unless three or more of the five intraoperative cultures taken are positive.

 

COMPLICATIONS

Broadly speaking, complications can be divided into those that are common to all THRs and those specific to a revision technique. This section focuses on complications specific to the revision subset.

Specific Complications

All revision techniques described rely on insertion of the stem in a runnier phase of the cement setting than with the cementing of a primary THA. This predisposes all these techniques to the potential complication not being able to fully seat the stem in case stem insertion is done too late during the curing of the cement.

Perforation of the Femur Perforation of the femur has been described with both cement in cement exchange (6) and cement-alone long stem revision (20). Long stems have an increased risk of cortical perforation especially in shorter patients and those with highly bowed femurs. In our series, there were 11 (8%) intraoperative femoral perforation. Although we have not encountered any case of femoral perforation in cement in cement revision, this complication has been described in 2 of the (1.5%) 136 cases reported by Duncan et al. (6). The perforations resulted in cement escape and, rarely, in long stems in the tip of the stem protruding through the anterior distal cortex

 

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of the femur. These complications had no effect on the patient function or component survivorship and none of them required any further surgical intervention.

Intraoperative Periprosthetic Fractures Intraoperative periprosthetic fractures are more frequent in revisions and especially in the presence of severe femoral deficiencies. In our series, a femoral periprosthetic fracture was encountered in 6% of the cement-alone long stem revisions. These were managed with additional wiring. To minimize the risk of periprosthetic fractures, we use a prophylactic cerclage wire around the proximal femur, use a long stem routinely, and always bypass diaphyseal cortical defects by a minimum of 2 cortical diameters.

Prosthesis Subsidence and Loosening after Impaction Bone Grafting Although in the centers with experience in the technique of impaction bone grafting this complication is of historical importance only, surgeons who are about to take up this excellent technique must be careful with the quality of bone they use (nonradiated versus irradiated), the technique of bone graft preparation (the amount of fat and other soft tissue debris left), and the technique of bone graft insertion (avoid the formation of filling voids in the graft) as all can lead to severe consequences leading to subsidence, rotational instability, this in turn can cause periprosthetic fracture. For example, before we started to use nonirradiated bone graft that was washed multiple times to remove fat, 4 of 23 femoral stem revisions with IBG failed by femoral loosening and required rerevision. This complication was not incurred after technique changes addressing these deficiencies (9).

 

RESULTS

Stem Revision through Cement in Cement Exchange

A typical radiograph of a cement in cement revision is shown in Figure 26-17.

In the largest published series to date, Duncan et al. (6) reported on the results of 136 cement in cement revisions. At a mean of 8 years, there was no rerevision for aseptic stem loosening and no aseptic stem loosening. Similarly, in our own series, we have no rerevision for loosening or radiographic loosening (7). In

 

addition, the average stem within cement subsidence averaged 0.8 mm (range 0 to 2 mm) (7) and was therefore similar with that of primary THA with cemented polished stems.

 

 

 

FIGURE 26-17 Case example of a revision with a same length stem through a cement in cement exchange performed to change stem version for recurrent dislocation. A: Preoperative radiographs. B: Postoperative radiographs.

Stem Revision with Impaction Bone Grafting

A typical radiograph of an impaction bone grafting revision is shown in Figure 26-18.

In the largest published series to date, Lamberton et al. (19) reported on the results of 540 revisions with femoral impaction grafting at a mean follow-up of 7 years (range 2 to 15).

 

 

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In that series, femoral component survivorship to the endpoint of rerevision for aseptic loosening was 98% (95% CI, 96% to 100%). When the endpoint was rerevision for any reason, including infection, the survivorship was 84.2% (72% to 90%). Importantly, this series included the early experience of the Exeter group and changes in the surgical technique. Another study reported that the probability of stem survival at 17 years was 100% (95% CI, 69% to 100%) for the endpoint rerevision for aseptic loosening and 96% (72% to 99%) for the endpoint femoral rerevision for any reason (22). This confirmed that these excellent results can be expected to persist at longer follow-up.

 

 

 

FIGURE 26-18 Case example of a revision with a same length stem through a femoral impaction bone grafting after a staged revision for infection. A: Preoperative AP hip radiograph. B: AP hip radiograph after a first-stage revision using a long stem temporary implant. C: AP hip radiograph demonstrating the long stem implanted at the first-stage revision through a transfemoral approach. Note the cables and wires used to stabilize the femoral osteotomy. D and E: AP pelvis and AP hip radiograph demonstrating the standardlength stem used in conjunction with impaction bone grafting at the second-stage revision.

Our results, after standardizing the technique including bone graft preparation, are in line with the other excellent results reported in the literature with only one femoral stem rerevision for infection and none for aseptic loosening or any other reason (9). In addition, the maximum prosthesis subsidence at the cement-bone interface in these cases was less than 2.7 mm at 2 years (9), which is what is expected of primary cemented polished stems (23). Importantly, and by contrast, the subsidence at the cement-bone interface was 0.1 mm, demonstrating excellent stability.

Stem Revision with Cement-alone Long Stem Revision

A typical radiograph of a cement-alone long stem revision is shown in Figure 26-19.

 

 

Our results of 137 cement-alone long stem revisions are the largest published series of a single stem design (20). At a mean 12 years (range 8 to 18), survival for aseptic loosening was 97% (95% CI, 91% to 100%) with only two revisions for aseptic loosening. Survival to re-revision of the stem for aseptic loosening was 100% (95% CI, 96% to 100%) in patients aged >70 years. Of the total eight femoral revisions, five were major involving involving the removal of the entire stem cement composite (two for aseptic loosening, two for infection and one in case of giant cell tumor), while the other three were minor and involved only the removal of the stem and its exchange through a cement in cement exchange (two for recurrent dislocation and one for infection) (20). These good results are even more impressive when considering that these revisions were performed in femurs with severe deficiencies as 80% of the femurs were classified prerevision as Paprosky Grades III and IV (24) and 57% as having an Endoklinik Grades III and IV (25).

 

FIGURE 26-19 Case example of a revision with a long stem cement-alone revision. A: Preoperative AP pelvis radiograph. B: Postoperative AP pelvis radiograph. C: Postoperative AP hip radiograph illustrating the long (200-mm) stem.

 

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3. Cross MB, Paprosky WG: Managing femoral bone loss in revision total hip replacement: fluted tapered modular stems. Bone Joint J 95-B(11 Suppl A): 95-97, 2013.

    

    

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7. Mandziak DG, Howie DW, Neale SD, et al.: Cement-within-cement stem exchange using the collarless polished doubletaper stem. J Arthroplasty 22(7): 1000-1006, 2007.

    

    

8. Halliday BR, English HW, Timperley AJ, et al.: Femoral impaction grafting with cement in revision total hip replacement. Evolution of the technique and results. J Bone Joint Surg Br 85(6): 809-817, 2003.

    

    

9. Howie DW, Callary SA, McGee MA, et al.: Reduced femoral component subsidence with improved impaction grafting at revision hip arthroplasty. Clin Orthop Relat Res 468(12): 3314-3321, 2010.

    

    

10. Schmitz MW, Busch VJ, Gardeniers JW, et al.: Long-term results of cemented total hip arthroplasty in patients younger than 30 years and the outcome of subsequent revisions. BMC Musculoskelet Disord 14: 37, 2013.

     

     

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12. Mäkelä K, Eskelinen A, Pulkkinen P, et al.: Cemented total hip replacement for primary osteoarthritis in patients aged 55 years or older: results of the 12 most common cemented implants followed for 25 years in the Finnish Arthroplasty Register. J Bone Joint Surg Br 90(12): 1562-1569, 2008.

     

     

13. Hook S, Moulder E, Yates PJ, et al.: The Exeter Universal stem: a minimum ten-year review from an independent centre. J Bone Joint Surg Br 88(12): 1584-1590, 2006.

     

     

14. Hailer NP, Garellick G, Kärrholm J: Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register. Acta Orthop 81(1): 34-41, 2010.

     

     

15. Thien TM, Thanner J, Kärrholm J: Randomized comparison between 3 surface treatments of a single anteverted stem design: 84 hips followed for 5 years. J Arthroplasty 25(3): 437-444.e1, 2010.

     

     

16. Briant-Evans TW, Veeramootoo D, Tsiridis E, et al.: Cement-in-cement stem revision for Vancouver type B periprosthetic femoral fractures after total hip arthroplasty. A 3-year follow-up of 23 cases. Acta Orthop 80(5): 548-552, 2009.

     

     

17. Fowler JL, Gie GA, Lee AJ, et al.: Experience with the Exeter total hip replacement since 1970. Orthop Clin North Am 19(3): 477-489, 1988. Erratum in: Orthop Clin North Am 20(4): preceding 519, 1989.

     

     

18. Iwase T, Kouyama A, Matsushita N: Complete bone remodeling after calcar reconstruction with metal wire mesh and impaction bone grafting: a case report. Nagoya J Med Sci 75(3-4): 287-293, 2013.

     

     

19. Lamberton TD, Kenny PJ, Whitehouse SL, et al.: Femoral impaction grafting in revision total hip arthroplasty: a follow-up of 540 hips. J Arthroplasty 26(8): 1154-1160, 2011.

     

     

20. Solomon LB, Costi K, Kosuge D, et al.: Revision total hip arthroplasty using cemented collarless double-

    taper femoral components at a mean follow-up of 13 years (8 to 20). An update. Bone Joint J 97-B: 1038-1045, 2015.

     

     

21. Solomon LB, Hofstaetter JG, Bolt MJ, et al.: An extended posterior approach to the hip and pelvis for complex acetabular reconstruction that preserves the gluteal muscles and their neurovascular supply. Bone Joint J 96-B(1): 48-53, 2014.

     

     

22. te Stroet MA, Gardeniers JW, Verdonschot N, et al.: Femoral component revision with use of impaction bone-grafting and a cemented polished stem: a concise follow-up, at fifteen to twenty years, of a previous report. J Bone Joint Surg Am 94(23): e1731-e1734, 2012.

     

     

23. Stefánsdóttir A, Franzén H, Johnsson R, et al.: Movement pattern of the Exeter femoral stem; a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years. Acta Orthop Scand 75(4): 408-414, 2004.

     

     

24. Paprosky WG, Bradford MS, Younger TI: Classification of bone defects in failed prostheses. Chir Organi Mov 79(4): 285-291, 1994.

     

     

25. Engelbrecht E, Heinert K: Klassifikation und behandlungsrichtlinen von knochensubstanzverlusten bei revisionsoperationen am huftgelenk: mittelfristige Ergebnisse. In: Primare und revisions-alloarthroplastik Huft- und Kniegelenk. Berlin: Springer-Verlag, 1987.