Valgus Total Knee Replacement

P ITFALLS

• The techniques described in this procedure have been almost exclusively studied and used in conjunction with posterior-stabilized (PS) implants and are therefore best suited for use with fixed-bearing PS or constrained knee prostheses (Clarke and Scuderi, 2004; Krackow and Mihalko, 1999).

   

• In knees with severe valgus preoperative deformities, even when the MCL appears to be functional, it may be difficult to create symmetric and equal flexion and extension gaps. In these cases, a constrained prosthesis should be available.

   

• Valgus knees resulting from prior high tibial osteotomy may not respond to soft tissue releases as anticipated and should be approached cautiously. In addition, prior hardware and distortion of the metaphyseal-diaphyseal relationship in either the coronal or sagittal plane make these cases especially challenging.

 

Valgus Total Knee Replacement

 

Indications

• Symptomatic arthritis of the knee with valgus limb alignment in middle-aged or older adults.

• Etiologies include osteoarthritis, inflammatory arthritis, and posttraumatic arthritis.

• Knees with mild to moderate valgus deformities, with femorotibial angles of less than 20–25°, and without significant attenuation of the medial collateral ligament (MCL) are suitable for correction with the “pie-crusting” (Clarke and Scuderi, 2004; Clarke

  et al., 2005) or multiple puncture (Elkus et al., 2004) technique.

• Knees with a severe valgus deformity but in which the MCL has a functional end point with valgus stress may be adequately managed with an alternative technique for soft tissue balancing. These techniques include a lateral femoral epicondyle osteotomy or a sequential release of the lateral structures from the lateral femur (Kanamiya et al., 2002).

• If the MCL is functionally compromised, then a constrained knee prosthesis or hinged implant should be used (Easley et al., 2000).

  Examination/Imaging

  Plain Radiographs

• Standing anteroposterior (AP) view (Fig. 1A)

  Controversies

  • Alternative techniques for soft tissue balancing of the valgus knee have been proposed. These include imbrication or advancement of the MCL (Healy et al., 1998), a lateral approach to the valgus knee (Keblish, 1991), and alternative sequences for releasing the lateral structures (Kanamiya et al., 2002; Krackow and Mihalko, 1999).

  • The role of the posterior cruciate ligament (PCL) in severe valgus deformity is controversial. While I routinely use a PS knee and believe sacrifice of the PCL facilitates correction of valgus deformity, others assert that the absolute need to sacrifice the PCL is rare.

   

  • Measure the femorotibial angle in order to anticipate the extent of lateral soft tissue releases required.

    • If the deformity is less than 20°, consider the pie-crusting technique.

    • If it is greater than 20–25°, consider lateral epicondyle osteotomy, but if there is also significant associated medial opening indicative of MCL attenuation (Fig. 1B, arrow), anticipate the need for a constrained prosthesis.

  • Evaluate for prior hardware that will need to be removed.

  • Exclude significant metaphyseal-diaphyseal offset distortion due to prior osteotomy.

  • Evaluate for bony erosion that may require augments or wedges.

• Lateral view (Fig. 2A)

  • Exclude significant metaphyseal-diaphyseal distortion or increased slope due to prior osteotomy.

  • Evaluate for bony erosion that may require augments or wedges.

     

     

     

     

     

     

     

    Valgus Total Knee Replacement

     

     

     

     

     

    75

     

    A

    FIGURE 1

     

    B

     

    A

    FIGURE 2

     

    B

     

     

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    Treatment Options

    • Adult patients of any age with isolated lateral compartment osteoarthritis or posttraumatic arthritis may be considered for a fixed-bearing lateral compartment unicondylar knee arthroplasty.

    • In younger adult patients (typically less than 50 years old), especially active males, with isolated or predominantly lateral compartment involvement, a varus-producing femoral osteotomy may be considered.

     

    Valgus Total Knee Replacement

     

• Merchant’s view

  • Many patients with valgus deformities exhibit significant abnormalities of the patellar-femoral articulation, including patellar erosion and subluxation or tilt that may compromise optimization of patellar tracking intraoperatively.

  • The Merchant’s view in Figure 2B demonstrates patellar subluxation and severe patellofemoral joint space narrowing (arrow).

• Standing hip-to-ankle view (Fig. 3)

  • The mechanical axis of the limb should be evaluated, and the presence of other hip or femoral hardware that may compromise standard operative techniques should be determined.

     

     

     

    FIGURE 3

     

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    Valgus Total Knee Replacement

     

    Surgical Anatomy

    • The iliotibial band (ITB) inserts on Gerdy’s tubercle (GT) on the anterolateral tibia (Fig. 4A and 4B and Fig. 5). The ITB functions as a lateral stabilizer at 0–30°.

     

     

    Plantaris

    Gastrocnemius lateral head

     

    Popliteus

    Lateral collateral ligament

    Iliotibial band

     

    Patellar tendon

    Biceps femoris

    A

     

     

    Adductor magnus

     

    Gastrocnemius medial head

     

    Semi-membranosus

     

    Popliteus

    Plantaris

     

     

     

    Gastrocnemius lateral head

     

    Lateral collateral ligament

     

    Posterior cruciate ligament

     

     

    FIGURE 4

    B Soleus

     

     

    ITB

     

    B

     

    GT

     

     

    FIGURE 5

     

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    Valgus Total Knee Replacement

     

    • The lateral collateral ligament (LCL) originates on the lateral femoral epicondyle (E) and inserts on the fibular styloid (FS), deep to the biceps femoris (B) (Fig. 6; see also Fig. 4A and 4B). It acts as a lateral stabilizer throughout the arc from 0° to 90°. Release of either the LCL or popliteus tendon alone will not destabilize the lateral knee.

    • The popliteus muscle originates on the posteromedial tibia and runs obliquely across the posterior tibia in a lateral and cephaled direction (see Fig. 4B). The popliteus tendon inserts just anterior to the LCL origin on the lateral femoral condyle. While the popliteus tendon functions as a lateral stabilizer throughout the arc of motion, the greatest effect is from 60° to 90° of flexion.

    • The posterolateral capsule or arcuate ligament complex includes the discrete fabellofibular ligament (FF) and arcuate ligament (A) as well as other less discrete fibers that form the posterolateral capsule (Fig. 7A and 7B).

  • The fabellofibular ligament, which originates on the fabella (F) in the lateral head of the gastrocnemius, inserts on the fibular styloid.

  • The arcuate ligament is a sheet of fibers that originates on the posterior femur and forms a triangular shape as it runs distally, inserting on the fibular styloid.

  • The posterolateral capsule is effective as a lateral stabilizer throughout the arc of motion but is greatest at 0–30 degrees from full extension (Kanamiya et al., 2002).

• The posterior capsule is a lateral stabilizer only in extension. Subperiosteal release is more likely to be required with concurrent flexion contracture.

• The PCL originates on the lateral wall of the medial femoral condyle in the intercondylar notch and inserts on the posterior tibia in the midline (see

  Fig. 4B). Release of the PCL eliminates a central pivot point and facilitates gap balancing in all cases, but is especially important in larger valgus deformities (Krackow and Mihalko, 1999).

• The lateral head of the gastrocnemius inserts on the posterolateral aspect of the femur (see Fig. 4A). The fabella is a sesamoid bone located in the lateral head of the gastrocnemius. Release of the lateral head of the gastrocnemius is more likely to be necessary when the knee has combined valgus deformity with flexion contracture.

 

E

B

LCL

 

FS

ITB

GT

 

 

Valgus Total Knee Replacement

 

FIGURE 6

 

LG

F

A

A

B

FF

P

 

 

79

 

A

FIGURE 7

B

 

LG

F

A

A

B

FF

P

 

 

• The biceps femoris runs distally along the posterolateral thigh and inserts on the fibular head, superficial to the LCL (see Fig. 4A, and “B” in Fig. 7). The peroneal nerve runs along the posterior margin of the biceps in the distal thigh.

• In the posterior midline of the knee, about 10 mm posterior to the tibial cortex, are located the posterior tibial artery and veins, and tibial nerve.

• The common peroneal nerve branches from the sciatic nerve in the posterior thigh and travels distally on the posterior edge of the biceps femoris (see “P” in Fig. 7).

  • At the level of the joint line, the nerve lies about 10–15 mm posterior to the posterolateral corner of the tibia. At this level, the lateral head of the

     

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    Valgus Total Knee Replacement

     

    gastrocnemius is interposed between the posterolateral tibia and nerve. This muscle body provides protection to the nerve when releasing the posterolateral structures (Clarke et al., 2004).

    • In extreme cases when even the biceps femoris must be released, the nerve is vulnerable to direct injury along the posterior edge of this muscle/ tendon insertion.

      • The lateral femoral condyle is often dysplastic in the valgus knee, and further erosion both distally and posteriorly may occur. This can lead to malrotation of the femoral component if the posterior condyles are used as a sole reference. Furthermore, due to the associated abnormalities of the patellofemoral joint that can occur in the valgus knee, the AP axis may be difficult to accurately identify. Therefore, in the valgus knee, it is especially important to ensure that the femoral component is oriented parallel to the transepicondylar axis.

         

        P EARLS

        • If the patient has any hardware in the femoral shaft or hip that precludes the use of standard intramedullary instrumentation on the femoral side, a radiographic marker may be positioned over the hip preoperatively and an AP radiograph of the hip obtained. This will facilitate intraoperative verification of limb alignment.

         

        Positioning

      • Standard positioning for total knee replacement.

      • Supine with a tourniquet high on the thigh.

        Portals/Exposures

      • An anterior midline skin incision with a medial parapatellar arthrotomy provides optimal exposure. However, use of a mini-subvastus or mini-midvastus arthrotomy can allow adequate visualization in experienced hands, and may be considered in knees with mild to moderate deformities.

         

         

        P EARLS

        • Prior incisions about the knee should be carefully evaluated and used if possible. However, lateral incisions from prior high tibial osteotomies may be difficult to incorporate. In these cases, if an adequate skin bridge of at least 5 cm can be maintained, a new midline incision may be performed.

           

          P ITFALLS

        • In the presence of multiple prior incisions, alternative prophylactic soft tissue coverage techniques may be required prior to total knee replacement. These include tissue expanders or soft tissue flaps.

         

         

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        P EARLS

        • After subperiosteal elevation of the proximal medial structures, a curved osteotome is passed around the medial tibia at the joint line to the posteromedial corner. This allows a bent Hohmann retractor to be placed deep to the fibers of the deep MCL, protecting it during bony resection.

           

        • When verifying limb alignment, a narrow spacer block will need to be used as no soft tissue releases have yet been performed. When checking alignment in extension, axial pressure should be maintained to make sure that the block is in contact symmetrically against the medial and lateral bone cuts.

           

          P ITFALLS

        • Placing the entry hole for the intramedullary femoral guide too laterally places the patient at risk for perforation of the femoral cortex or malpositioning into too much valgus. Instead, the entry hole should be slightly medial, just anterior to the intercondylar notch.

         

        Valgus Total Knee Replacement

         

        Procedure

        Step 1

        • A medial parapatellar arthrotomy is first performed. Next, the suprapatellar fat pad, the lateral patellofemoral ligament, and a portion of the retropatellar fat pad are excised.

        • The distal arthrotomy is extended along the medial edge of the patellar tendon. A limited subperiosteal elevation of the proximal 3–4 cm of the medial soft tissue is sharply performed. Extensive elevation of the MCL insertion should be avoided as this may exacerbate the relative laxity of the MCL and make

          it more difficult to adequately lengthen the lateral structures.

        • The knee is then flexed and the ACL and PCL are released from their femoral and tibial attachments.

        • The basic tibial and distal femoral bone cuts are performed with mechanical guides or computer navigation.

          • In many cases, minimal distal lateral resection of 1–2 mm will be performed due to underlying hypoplasia and erosion of the lateral femoral condyle.

• Femoral component sizing and rotational position should then be selected. Femoral component rotation is set parallel to the transepicondylar axis, and the anterior and posterior femoral cuts are performed (Fig. 8: AP  AP axis; E  transepicondylar axis; long arrow  lateral epicondyle; short arrow  medial epicondyle).

  Instrumentation/ Implantation

  • Computer navigation may be used for verification of the tibial and distal femoral cuts. In cases with femoral shaft or hip hardware that interferes with intramedullary femoral cutting guides, computer navigation is particularly helpful.

   

• Meniscal remnants and posterior osteophytes are then excised.

 

 

AP

 

E

 

 

FIGURE 8

 

 

 

82

 

Valgus Total Knee Replacement

 

A

FIGURE 9

B

 

• The alignment of the tibial cut and overall limb alignment are verified using a spacer block and external guide rods at 90° (Fig. 9A) and in full extension (Fig. 9B).

  Step 2

  Controversies

  • The order of femoral and tibial bone cuts in this technique is irrelevant, but alternative techniques that orient the femoral rotation relative to the tibial cut require a “tibia-first” protocol (Elkus et al., 2004).

   

• Once accuracy of the basic bone cuts and limb alignment have been verified, a spacer block is used to assess the symmetry of the medial and lateral soft tissue tension in flexion and then extension. Figure 10 shows a spacer block in extension demonstrating tight lateral structures with gapping medially with valgus stress. The overall balance of the flexion and extension gaps is also evaluated (Clarke and Scuderi, 2004).

• In mild to moderate valgus knees in which the lateral

  structures are tight, the multiple puncture or pie-crusting technique is used.

• First, with the knee in extension, a laminar spreader is inserted in the medial side and the soft tissues gently tensioned (Fig. 11A and 11B). Next, the lateral structures are systematically lengthened.

   

   

   

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  P EARLS

  • Without the transverse incision through the posterolateral capsule, which includes the arcuate and fabellofibular ligaments and likely a portion of the LCL, only small valgus deformities can be adequately corrected.

     

  • The tip of the #15 blade that is used to perform the posterolateral capsular incision and the multiple punctures should not penetrate more than 5 mm into the soft tissues in order to minimize risk to the peroneal nerve (Clarke et al., 2004).

     

  • The ability to gradually titrate the lateral release is central to this technique and allows a systematic approach to be used when learning this method.

   

  Valgus Total Knee Replacement

   

  FIGURE 10

   

  • The popliteus tendon is identified in the posterolateral corner of the knee (see Fig. 11A, arrow). It is preserved throughout the balancing process in order to ensure stability of the lateral side, particularly in flexion. Preservation of the popliteus tendon helps to prevent the risk of dislocation of the PS cam and post by eliminating the tendency for lateral liftoff in flexion that can occur if the lateral side is over-released.

 

 

 

 

B

 

 

A

FIGURE 11

 

 

 

84

 

Valgus Total Knee Replacement

 

A B

FIGURE 12

• Next, at the level of the tibial bone cut, a #15 blade is used to make a transverse incision through the posterolateral capsular complex. A transverse incision at the level of the tibial bone cut is performed anterior to the popliteal tendon, which is preserved (Fig. 12A and 12B).

   

  P ITFALLS

  • The peroneal nerve lies approximately 10–15 mm from the posterolateral corner of the tibia and is at risk for direct injury if the tip of the blade penetrates deeply (Clarke et al., 2004).

     

  • If it is necessary to release the popliteus tendon from the femur, the knee should be evaluated in flexion in the “figure-4” position that applies a varus stress. In this position, if a PS prosthesis has been used and there is significant lateral liftoff, the knee is at risk for the femoral cam riding over the PS post, resulting in a dislocation. In this circumstance, use of a constrained articulation should be considered even if the extension gap is well balanced.

   

• Following this step, multiple punctures or pie-crusting perforations are made in a transverse manner through the ITB and lateral capsule, producing a gradual elongation of these structures (Fig. 13A and 13B) (Clarke and Scuderi, 2004; Clarke et al., 2005; Elkus et al., 2004).

• Although no specific attempt is made to isolate and release the LCL with this technique, it is likely that, during this process, the LCL is lengthened.

  • A second laminar spreader is then placed laterally and tensioned. If a symmetric extension gap has been produced, then laminar spreaders are removed and a spacer block is used to reevaluate the flexion (Fig. 14A) and extension (Fig. 14B) gap symmetry.

• In most cases, a thicker spacer block than initially used will be required. If further release is required, the spacer block is removed and the knee is again placed in extension with a laminar spreader on the medial side.

• Additional punctures through the lateral structures are then performed. This cycle is repeated as required to achieve symmetric gaps.

• Occasionally, this technique does not allow adequate correction of the lateral contractures. If

 

 

 

 

Valgus Total Knee Replacement

 

A B

FIGURE 13

 

85

 

the lateral side is tight in tension, this may require releasing the ITB at the joint line or from Gerdy’s tubercle (author’s preference). However, if the lateral side is only tight in flexion, then the popliteus tendon may need to be released from the femur.

 

 

 

A B

FIGURE 14

 

86

 

Controversies

• Ranawat has suggested that use of an electrocautery device is preferable for performing the transverse cut through the posterolateral capsule and arcuate complex. However, there is no evidence that the risk of direct laceration to the peroneal nerve is greater with the use of a scalpel blade than is the potential risk of thermal injury with the electrocautery device. Indeed, both methods appear clinically safe when performed carefully (Clarke

et al., 2004, 2005; Elkus et al., 2004).

 

Valgus Total Knee Replacement

 

Step 3

• Severe valgus deformity will usually require an

  alternative to the pie-crusting or multiple puncture technique.

  • One option is to release the lateral structures from the femur. If the lateral side is tight in flexion and extension, the popliteus tendon and LCL can be released either sharply or with an electrocautery.

  • Another alternative is to perform a lateral epicondyle osteotomy (Fig. 15A) that creates a sliver of bone a few millimeters thick by about 2 cm round with the popliteus tendon origin (Fig. 15B, long arrow) and LCL attachments (Fig. 15B, short arrow) on the lateral femoral epicondyle (author’s preference).

• If the flexion gap is improved with this maneuver, the knee is then evaluated in extension.

   

  P EARLS

  • In knees with a severe valgus deformity, it is usually preferable to proceed with one of the alternative methods for lateral soft tissue releases noted in Step 3 without first performing a pie-crusting type of release as extensive puncture-type lengthening leaves the lateral structures macerated.

   

  • If the lateral side is still tight in extension, the ITB is released at the joint line or with multiple punctures, but may alternatively be released subperiosteally from Gerdy’s tubercle (author’s preference). In some cases, further releases are required. If so, the posterior capsule and then the lateral head of gastrocnemius will need to be released from the femur with an electrocautery and periosteal elevator (Fig. 16). This is best performed with the knee in flexion. These structures may be elevated from the posterolateral femur with a periosteal elevator.

  • Release of the biceps femoris is best avoided due to the proximity of the peroneal nerve. However, very rarely it may be considered to be the last remaining contracted lateral structure. In these rare cases, the anterior portion of the tendon may be transected, but the proximity of the peroneal

  nerve along the posterior edge of this structure should be taken into account.

  Postoperative Care and Expected Outcomes

• On the day of surgery, a drain is used with a sterile dressing. The knee is placed in extension but no form of immobilization is used. No continuous passive motion (CPM) is used.

• Femoral and sciatic nerve catheters are placed preoperatively, but the sciatic catheter is not loaded until distal motor function of the anterior tibialis, extensor hallucis longus, and gastrocnemius-soleus

 

 

 

Valgus Total Knee Replacement

 

A

FIGURE 15

B

 

have been documented by the surgical team in the recovery room. Extreme external rotation of the leg is avoided in a leg with peripheral sensory block with a pillow or foam block at the ankle to avoid external compression of the peroneal nerve.

 

 

 

 

87

 

 

P ITFALLS

• In severe valgus deformity, especially when the MCL has become functionally attenuated, it may not be possible to adequately lengthen the lateral structures to create balanced and symmetric flexion and extension gaps without significant elevation of the joint line.

   

• When very large polyethylene inserts are required to accommodate the lengthening that has occurred, the peroneal nerve may be indirectly compromised by a traction-type injury. Therefore, in patients with severe deformities, under-release of the lateral structures and use of a constrained prosthesis may be considered (Fig. 17) (Easley et al., 2000).

   

• If either the LCL or popliteus tendon is preserved, lateral instability is unlikely. If release of both is required to correct the underlying contracture, use of a constrained prosthesis should be considered, especially if there is lateral liftoff when the knee is examined in the figure-4 position (90° of flexion with a varus stress).

 

FIGURE 16

 

Controversies

• The exact order of lateral soft tissue releases in cases of extreme valgus is controversial. In difficult cases, it is important to evaluate the knee in flexion and extension and consider the anatomic function of the individual lateral structures (Kanamiya et al., 2002; Krackow and Mihalko, 1999). Graduated release of the individual structures can then be undertaken to correct the specific scenario encountered. In these cases, early release of the LCL is appropriate as this appears to be the primary lateral stabilizer and exerts an effect throughout the range of motion (Krackow and Mihalko, 1999).

 

 

88

 

 

P EARLS

• If there is concern that an injury to the peroneal nerve has occurred intraoperatively, the knee is flexed about 30° in order to relax the sciatic nerve. Also, the sterile dressing is loosened to ensure that any potential external compression is relieved. Peripheral nerve blocks are also discontinued in order to ensure that better clinical monitoring can be performed.

   

  P ITFALLS

• Poor positioning in a CPM machine or otherwise, in conjunction with peripheral nerve blocks, may be associated with risk of external compression injuries occurring to the common peroneal nerve (Idusuyi and Morrey, 1996).

 

Valgus Total Knee Replacement

 

FIGURE 17

 

 

Controversies

• Intraoperative peroneal nerve injury is most commonly due to indirect injury from traction or compression by a retractor. Therefore, early exploration of these injuries is controversial. In most cases, observation is appropriate (Idusuyi and Morrey, 1996; Mont et al., 1996). If there is no evidence of early recovery in the first week or two, a baseline electromyogram is obtained. Also, an ankle-foot orthosis is used to facilitate ambulation and to prevent Achilles tendon contractures from occurring. In cases in which no functional recovery is identified within the first 3–6 months, operative decompression of the nerve may be considered (Mont et al., 1996).

 

 

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Valgus Total Knee Replacement

 

Evidence

Clarke HD, Fuchs R, Scuderi GR, Scott WN, Insall JN. Clinical results in valgus total knee arthroplasty with the “pie crust” technique of lateral soft tissue releases. J Arthroplasty 2005;20:1010-4.

 

This paper reported short-term to midterm clinical results of total knee arthroplasty (TKA) performed in patients with preoperative valgus deformities. Good functional outcomes were reported with no cases of postoperative instability. Intraoperative gap balancing was performed with the pie-crusting type of graduated lateral soft tissue releases.

 

Clarke HD, Schwartz JB, Math KR, Scuderi GR. Anatomic risk of peroneal nerve injury with the “pie crust” technique for valgus release in total knee arthroplasty. J Arthroplasty 2004;19:40-4.

 

This magnetic resonance imaging study examined the anatomic relationships at the posterolateral corner of the knee. The lateral head of the gastrocnemius muscle is interposed between the capsule and nerve and acts to protect the nerve from direct injury during release of the posterolateral structures.

 

Clarke HD, Scuderi GR. Correction of valgus deformity in total knee arthroplasty with the pie-crust technique of lateral soft-tissue releases. J Knee Surg. 2004;17:157-66.

 

Intraoperative medial and lateral soft tissue balancing in the valgus knee was evaluated with the use of a tensiometer. Use of the pie-crusting type of lateral soft tissue release reliably produced balanced flexion and extension gaps.

 

Easley ME, Insall JN, Scuderi GR, Bullek DD. Primary constrained condylar knee arthroplasty for the arthritic valgus knee. Clin Orthop. 2000;(380):58-64.

 

This study evaluated midterm to long-term clinical results of TKA performed in valgus knees with a constrained knee prosthesis. Good outcomes were noted in elderly, low-demand patients when a constrained prosthesis was used to provide stability in lieu of creating balanced flexion and extension gaps. No clinical or radiographic failures occurred in the living patients or prior to death in those who died. In these 44 cases, no peroneal nerve injuries were identified, likely due to the avoidance of lengthening that occurs if extensive lateral releases are performed.

 

Elkus M, Ranawat CS, Rasquinha VJ, Babhulkar S, Rossi R, Ranawat AS. Total knee arthroplasty for severe valgus deformity: five to fourteen-year follow-up. J Bone Joint Surg Am. 2004;86:2671-6.

 

The authors reviewed midterm to long-term clinical results for TKA performed with the multiple puncture technique of lateral soft tissue releases in valgus knees. The authors described essentially the same technique as the pie-crusting technique of lateral soft tissue releases described elsewhere. The horizontal release of the posterolateral capsule was performed with an electrocautery rather than with the tip of a scalpel blade.

However, its unclear that this reduced the risk of direct injury to the peroneal nerve. Instead of direct laceration, the potential for thermal injury exists with the electrocautery, and this may penetrate in a more unpredictable manner through the posterolateral soft tissues. However, good outcomes were reported with no nerve injuries.

 

Healy WL, Iorio R, Lemos DW. Medial reconstruction during total knee arthroplasty for severe valgus deformity. Clin Orthop. 1998;(356):161-9.

 

An alternative technique to isolated lateral soft tissue releases in the valgus knee is described. Symmetric medial and lateral soft tissue tension was achieved through the use of lateral soft tissue releases combined with reconstruction of the MCL. In this technique, the MCL origin attached to its epicondylar bone block is elevated. Next, the metaphyseal bone underlying the epicondyle is impacted; the bone block with the MCL attachment is then recessed into this cavity and secured with a suture passed through to the lateral condyle. Good clinical results are reported.

 

Idusuyi OB, Morrey BF. Peroneal nerve palsy after total knee arthroplasty. J Bone Joint Surg Am. 1996;78:177-84.

 

 

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The authors reported a retrospective clinical series of patients who developed peroneal nerve palsy after TKA. In this series, in addition to preoperative valgus deformity, epidural anesthesia that may have resulted in diminished sensation and external nerve compression, which appeared to be risk factors in the development of peroneal nerve injuries. Nerve recovery without surgery was variable, with about 50% of cases resolving completely.

 

Kanamiya T, Whiteside LA, Nakamura T, Mihalko WM, Steiger J, Naito M. Ranawat Award Paper: Effect of selective lateral ligament release on stability in knee arthroplasty. Clin Orthop. 2002;(304):24-31.

 

This cadaver study examined the functional contributions of each of the lateral structures of the knee to lateral stability. The results provided important information that may be applied to balancing the valgus knee. This is especially valuable when large or combined deformities are encountered intraoperatively. The authors emphasized the importance of examining the knee in flexion and extension and then performing sequential releases of the particular lateral structures that are most likely to be producing the deforming forces in the individual scenario.

 

Keblish PA. The lateral approach to the valgus knee: surgical technique and analysis of 53 cases with over two-year follow-up evaluation. Clin Orthop. 1991;(271):52-62.

 

Rather than performing TKA through a standard medial approach and then undertaking lateral soft tissue releases to balance the knee, the technique described in this paper is for a lateral approach to the knee that simultaneously allows release of the lateral structures. While good results are reported, this technique has not been widely adopted, likely due to the technically demanding nature. The surgeon’s perspective is reversed, the patella is difficult to mobilize medially without elevating the tendon insertion, and problems with soft tissue closure or wound healing may be encountered.

 

Krackow KA, Mihalko WM. Flexion-extension joint gap changes after lateral structure release for valgus deformity correction in total knee arthroplasty: a cadaveric study. J Arthroplasty 1999;14:994-1004.

 

Alternative sequences for release of the lateral structures were examined in a cadaver model. Early release of the LCL provided a more uniform release of the joint gap.

Releases of the ITB and popliteus tendon were suggested to titrate the extent of the release after LCL release. The PCL had been released in all cases. The study is potentially biased by the use of cadaveric specimens that did not have valgus deformities. However, the information is still valuable for understanding the function of the lateral structures.

 

Mont MA, Dellon AL, Chen F, Hungerford MW, Krackow KA, Hungerford DA. The operative treatment of peroneal nerve palsy. J Bone Joint Surg Am. 1996;78:863-9.

 

This paper reported a retrospective case series of 31 patients who were treated with surgical decompression of the peroneal nerve when spontaneous recovery following nerve injury had not occurred by at least 2 months. In the majority of cases, improvement in nerve function occurred by 36 months after surgery; however, there was no randomization, and the only controls were a small group of patients treated nonoperatively because they had refused surgery.