Introduction                       

Developmental dysplasia (DDH) leads to early osteoarthritis of the hip and poses a challenge for the reconstructive hip surgeon. It is characterized by a spectrum of anatomical abnormality, bony deficiency and a high incidence of complications in patients who are young and active.

Mild cases with only minor deformity can be successfully treated with standard total hip arthroplasty with little consideration for the typically encountered problems. At the extreme end, the typical gross anatomical abnormalities (acetabular hypoplasia, femoral neck anteversion and leg length discrepancies with high riding trochanters) pose problems that have to be addressed in order to successfully reconstruct the hip. Indeed, authors in the past have recommended avoiding arthroplasty in these patients.1,2

Dysplasia, per se, is the most common and probably the most under-diagnosed cause of osteoarthritis of the hip.3 Subtle dysplasias if not appreciated can have a negative effect on the results of otherwise well performing implants with surface replacement having a 3.2% risk of failure in DDH compared to 2.0% early failure in osteoarthritis.4

Appropriate implant selection and meticulous surgical technique are of utmost importance in ensuring optimal longevity of the implant in this relatively young group of patients. This chapter highlights the inherent difficulties in performing total hip replacement in DDH and the senior author’s preferred techniques are presented (WJMB).

 

Anatomy                        

It is important to understand the anatomy of the dysplastic hip to be able to successfully reconstruct it. On the acetabular side there is often a high hip center, poor bone and the small size of components needed is often not available in all systems. The acetabulum is always shallow and deficient anterior and anterosuperiorly.5 With high dislocation the central acetabular bone is very thin, and the acetabulum is anteverted, and very shallow from front to back and the acetabulum is anteverted.

The femoral problems are just as difficult. The femoral neck is short and there is a small straight canal. The neck is usually markedly anteverted from ten to sixty degrees6 (Fig. 25.1). The straight canal is an advantage in reconstruction as it makes femoral shortening easier.7 Although the neck shaft angle appears more valgus on X-ray with increasing dysplasia, Sugano et al8 have shown a decrease in neck shaft angle with worsening dysplasia which has relevance in reconstruction for offset and leg length. The canal shape is more abnormal as the subluxation becomes worse. The primary femoral abnormality is diaphyseal rotation between the lesser trochanter and the isthmus.

 

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Figure 25.1: The femoral neck in dysplasia may be anteverted from ten to sixty degrees

 

Total Hip Arthroplasty

 

The soft tissues are affected with the hamstrings, adductors and quadriceps shortened. The psoas is thickened and short and the capsule is thickened and deformed. The rotators are horizontal and incline inferiorly and the sciatic nerve is shortened. Although the anatomy of the femoral nerve is abnormal, exiting laterally and superiorly from the pelvis and also the profunda femoris artery, with adequate care this does not seem to be as great an issue in reconstruction as the posterior structures.9

 

Indications                        

Pain and disability are the major reasons for total hip arthroplasty. The indications for hip reconstruction in this group of patients are not substantially different from the indications for routine hip arthroplasty. The vast majority of patients seek surgery for pain relief and cite interference with activities of daily living as a secondary reason for seeking intervention. The severity and contribution of leg length discrepancy, knee function, lumbar spine compensation and degeneration also contribute to the impetus towards surgery.

Pain is the major indication for surgical intervention, even for the severe dysplasias, and, in our opinion, even in those patients with bilateral dislocations. The notion that patients with bilateral total dislocations walk poorly but have little or no pain and function well for decades, not requiring reconstruction may be an old fashioned one. It is our experience that these patients do come to reconstruction and report good or excellent outcomes.6

In severe adult DDH, radiographic changes are dramatic with a high riding hip but no osteoarthritis. The lack of arthritis does not necessarily mean that they don’t present with pain as a primary indication for intervention. In these patients, leg length inequality is an issue and counseling on what can be reasonably achieved is necessary. The majority of patients are young and previous surgery has often been performed so longevity of the reconstruction will be compromised.

Specific features are important in the preoperative counseling of this group of patients who present to the orthopaedic surgeon at an early age. Loss of joint space secondary to the developmental abnormality may progress rapidly but it is important to extend the longevity of the native hip joint as long as possible through the use of nonoperative means.

In the severe forms of this disorder, there needs to be clear recognition of the risk of increased complications and complexity of the surgery. Nonunion of femoral osteotomies and acetabular graft are special considerations. Sciatic and femoral nerve palsies are a function of the amount and method of lengthening that is attempted.

In summary, the indications should be clear in both the minds of the surgeon and patient and there should be thorough counseling with regard to the general and specific risks.

 

Classification                       

DDH presents wide spectrum of deformities with their own inherent difficulties that a classification system is necessary in order to compare data from different studies.

A number of such systems have been described. However, there is clearly a need for a universally accepted system so that all authors can report their results in a common language. At this time, the classification system of Crowe et al comes closest to fulfilling this need, particularly regarding stratification for the assessment of outcomes.10

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In almost all radiographic assessments of DDH, the height of the pelvis, the junction of the head and neck, and the teardrop can be identified. Crowe et al. classified dysplastic hips radiographically into four categories on the basis of the extent of proximal migration of the femoral head.

Total Hip Replacement in Developmental Dysplasia of the Hip

 

It was estimated that the normal height of the femoral head is 20 percent of the height of the pelvis. They differentiated their classes on the basis of the distance from the bottom of the teardrop to the junction of the head and neck. In normal hips, these landmarks are at approximately the same level.

The proximal migration of the femoral head can then be expressed as a percentage of the height of the pelvis or as a percentage of the height of the femoral head:

• Class I represents proximal displacement of less than 10 percent of the height of the pelvis or, in other words, proximal subluxation of the femoral head of less than 50 percent of the height of the femoral head.

• Class II represents proximal displacement of 10 to 15 percent of the height of the pelvis or 50 to 75 percent of the height of the femoral head.

• Class III, values are 15 to 20 percent of the height of the pelvis or 75 to 100 percent of the height of the femoral head.

• Class IV is assigned when the proximal migration is more than 20 percent of the height of the pelvis or more than 100 percent of the height of the femoral head.

  Hartofilakidis et al11 provided a simple and effective classification of adult DDH. Three categories were described:

• Dysplasia

• Subtotal dislocation

• High or total dislocation.

In dysplasia, the femoral head is subluxated but is still contained within the original (true) acetabulum. There is usually a superior segmental deficiency and a shallow acetabulum due to an osteophyte covering the acetabular fossa. In subtotal dislocation, the femoral head articulates with a false acetabulum that partially overlaps the true acetabulum. There is both an anterior and a posterior segmental deficiency, and the acetabulum has a narrow opening and is of inadequate depth. In three quarters of cases of subtotal dislocation acetabular anteversion is noted.11 In a high dislocation, the femoral head is superior and posterior and articulates with a hollow in the acetabular wing. The entire rim of the true acetabulum is deficient, and the acetabulum is excessively anteverted, lacks depth, and has a narrow opening. The bone stock is mainly located superoposteriorly.

The classification system of Crowe et al is most widely used and allows for comparison of patient’s presentations, operative treatments and outcomes and it is for these reasons that we favor this.

 

Surgical                    Technique                    

TEMPLATING

Meticulous preoperative planning is essential in order to assess leg length, the need for bone osteotomy and bone augmentation. It is also vital to ensure the availability of specific prostheses which may not be routinely stocked. Plain radiographs may be supplemented with Judet views to characterize the nature of the acetabular hypoplasia.

Computerized tomographic (CT) scans are useful in assessing acetabular coverage and version. Some have used CT scans in precise quantification of leg length inequality and in designing customized femoral implants.12

In the planning of a total hip arthroplasty for the treatment of osteoarthritis secondary to hip dysplasia or dislocation, detailed templating is vital, as it provides a check towards the selection of the prosthesis that is used and influences the surgical approach that is performed.

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On the acetabular side, the position of the true acetabulum should be identified, and a decision should be made whether to attempt to restore the acetabulum to its original location. Once the cup position is planned, the proposed amount of lengthening can be established and the femoral osteotomy requirements can be quantified.

Total Hip Arthroplasty

 

The degree of anteversion of the acetabulum should also be defined, as should the adequacy of the bone stock for satisfactory fixation and coverage. A plan should be formulated, including an estimate of the size of the component to be used, the preferred method of fixation and the need for bone graft and special equipment.

On the femoral side, the size of the femoral canal and the need for special or custom components should be assessed. Particular attention should be paid to the need for smaller inside cup diameters and femoral heads, as these may not be part of the standard armamentarium of many hospitals.

We believe that templating as part of the preoperative assessment is indispensable. It should always include decisions regarding the securing of a wide but safe exposure, the solutions to the problems posed by a hypoplastic or dysplastic acetabulum, the treatment of the distorted or hypoplastic femur, the assessment and relative equalization of any limb-length discrepancy, and the restoration of abductor function.

 

Templating Tips and Tricks (WJMB)

Templating is not completely accurate and is usually done on the normal side. It is important to have an AP X-ray centered on the symphysis (Fig. 25.2), and an AP and lateral of the side to be operated on templating’s primary purpose. Its primary purpose is to make you think about the problems and therefore foresee surgical issues. In DDH, the pathological side is the one templated as it is so different from a normal hip.

I use a white Chinagraph pencil as other colours obscure the X-ray. This case is a 35-year old female with Crowe IV DDH on left and previous femoral osteotomy (Figs 25.3 and 25.4). The first step is to use the lateral as a guide to cup size as in any case it is the anterior and posterior walls that determine cup size (Fig. 25.5). In this case-the deformity in the proximal femur is mapped by drawing the longitudinal axis of the proximal and distal part of the femur (Figs 25.6 to 25.8). This gives you an idea where the osteotomy should be made.

Femoral sizing and length of prosthesis can be assessed as well (Fig. 25.9).

 

 

In the AP, a line is drawn across the two ischium to judge the height of the head compared to the normal size and leg length problems (Fig. 25.2). Then the tear drop is marked (to give

 

Figure 25.2: Templating for dysplastic hip is done on the pathological side

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Figure 25.3: Anteroposterior radiograph of a 35 year old femal with Crowe IV dysplasia on left side and previous femoral osteotomy

Figure 25.4: Lateral radiograph of the patient. Note the anterior angulation

 

 

 

 

Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.5: Lateral view helps decide the size of the acetabular cup

Figure 25.6: Mapping of the length and axis of the proximal femoral segment

 

an idea of lower extent of cup and depth of wall) and the cup size and orientation is assessed (Figs 25.10 and 25.11).

The lateral endosteal surface of the proximal and distal femur is marked, this gives you an idea of how lateral into the trochanter you need to get and also with a parallel, mid femoral line, an idea of your osteotomy point (Figs 25.12 to 25.14). Then femoral prosthesis

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Total Hip Arthroplasty

 

Figure 25.7: Mapping: Axis of the distal fragment

 

 

 

 

Figure 25.9: Templating for the femoral component

Figure 25.8: Mapping: Magnitude of the location deformity is measured and site of osteotomy planned

 

 

 

Figure 25.10: Teardrop is marked

 

 

 

 

Figure 25.11: Acetabular cup size and orientation are assessed

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Figure 25.12: Lateral endosteal surfaces of the proximal and distal femur are marked

Figure 25.13: Assessment is made of the entry pain into the trochanter

Figure 25.14: Estimated site of the femoral osteotomy

 

 

 

Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.15: Femoral prosthesis templating for size

Figure 25.16: Femoral prosthesis templating for length

Figure 25.17: Templating for femoral prosthesis—size and length

 

size and length is checked with the femoral templates (Figs 25.17 to 25.19). The ischial line is extended to the femur and the distance from the center of the femoral head and the center of the acetabular cup to this line gives an idea of femoral shortening required (Figs 25.15 and 25.16). The plan is then followed (Fig. 25.20). Note the grafting around the osteotomy site. The polyethylene in this patient wore in 8 years, and the cup was changed and the previous femoral head autograft allowed a much more simple reconstruction (Figs 25.21 and 25.22).

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Total Hip Arthroplasty

 

Figure 25.18: Ischial line is extended to femur

Figure 25.19: Distance from ischial line to femoral read and the centre of the acetabulum gives an idea about the amount of shortening required

Figure 25.20: Postoperative radiograph after femoral osteotomy and THA. Note that femoral head augmentation of acetabulum was need

 

 

 

Figure 25.21: 8 years follow-up radiograph showing wear of polyethylene. Courtesy: Dr P Walker

Figure 25.22: Revision of hip. Note that previous femoral head augmentation allowed a simple reconstruction of the acetabulum. Courtesy: Dr P Walker

 

 

APPROACH

Any approach can be used in the less severe cases of DDH. Many different techniques have been used in the severe cases.

With high dislocation transtrochanteric or subtrochanteric approaches have been recommended. The transtrochanteric approach allows excellent exposure of the acetabulum.13 I feel the risk of nonunion does not justify this approach. The subtrochanteric22 approach although excellent for exposure and femoral shortening if necessary does not offer any advantage over the posterior approach and subtrochanteric shortening.7

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.23: Crowe dysplasia left hip

Figure 25.24: Femoral shortening by a very low neck cut resulted in a high trochanter and poorer mechanics

 

Glassman et al have popularized the trochanteric slide.14,15 This is a modified trochanteric osteotomy, but again I feel it has no advantage over the posterior approach with femoral shortening.

Smith-Petersen, iliofemoral and aggressive soft tissue releases off the ilium have all been advocated.16-18 These approaches have led to increased sciatic nerve palsies and weakness of the hip.

My preferred approach is a classic posterior approach and subtrochanteric femoral shortening if necessary. It is important to do a femoral shortening if you feel a very low neck cut will give you a very high trochanter and a tight reduction (Figs 25.23 and 25.24).

 

Approach Tips and Tricks (WJMB)

 

 

The patient should be placed as far towards the opposite side of the table as possible and the bottom leg should be straight (Fig. 25.25). This allows you to adduct the leg further off the table which gives greater access to the femur. A curved incision is made centerd on the

 

Figure 25.25: Positioning of the patient on the operation table

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Total Hip Arthroplasty

 

Figure 25.26: Curved incision centred on the greater trochanter for posterior approach

 

Figure 25.27: Increased depth of fat warrants longer incision to get adequate cup position

 

 

greater trochanter (Fig. 25.26). This is usually slightly longer than your traditional approach as the modular femoral stems need more room to prepare the femur than broached ones.

The fat depth is measured, as a fat depth of over 5 centimetres requires an incision over 12 centimetres to get adequate cup position (Fig. 25.27).

A normal incision through fascia lata is made and I split the fibers of tensor fascia lata with my hand. The large Charnley retractor is more suitable even for thin people as it keeps the gluteus maximus away from the operating field.

The sciatic nerve is palpated and gentle dissection of the fat and vessels in front of the nerve are undertaken. The position of the nerve in relation to the trochanter is marked so

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.28: Curved retractor is placed under gluteus medius and the rotators and pyriformis identified

 

Figure 25.29: Rotators are oblique and pyriformis is higher in high dislocations

 

damage does not occur during the case. A curve retractor is placed under gluteus medius and the rotators and pyriformis identified (Fig. 25.28).

The posterior border of gluteus minimus is dissected off the superior border of the pyriformis. You will find the rotators are oblique in high dislocations and the pyriformis is higher (Fig. 25.29). A suture is placed in the pyriformis (Fig. 25.30).

The rotators are dissected off the greater trochanter and all the quadratus femoris as leg lengthening may be required. The gluteus maximus insertion is tagged with a suture as this will need to be excised if lengthening is required (Figs 25.31 and 25.32). The leg length guide is attached to the iliac wing and the most lateral point of the greater trochanter. This gives an idea of how much you lengthen the patient and the offset (Fig. 25.33).

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Total Hip Arthroplasty

 

Figure 25.30: A suture is placed in pyriformis

 

 

 

Figure 25.31: Rotators are dissected off the greater trochanter gluteus maximus tendon on left

 

Figure 25.32: Gluteus maximus insertion is tagged

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.33: Leg length guide in place

 

Figure 25.34: Orientation of femoral head to the acetabulum is marked

 

 

Before the hip is dislocated, its orientation to the acetabulum is marked so the correct orientation of the head to the acetabulum is known and this facilitates correct graft placement if you use the femoral head (Fig. 25.34). The hip is dislocated and the femoral head mark can be seen (Fig. 25.35).

The greater trochanter is prepared with a starting reamer (Fig. 25.36). Then a long curette is placed down the femur to be certain not to perforate the shaft (Fig. 25.37). Then straight reamers are used. If femoral shortening is predicted you must ream with straight reamers greater by the amount you anticipate shortening (usually 3 to 6 centimetres) (Figs 25.38 and 25.39). With the straight reamer in situ the offset of the femoral head is measured (Fig. 25.40); this gives you an idea, with the templating which offset stem you will use. It is rare to use more than a standard offset. The neck is cut with a trial stem as a guide, a sloped cut with nonmodular stems and a flat cut with modular stems (Figs 25.41 to 25.43).

 

Acetabular Tips and Tricks (WJMB)

The acetabulum has to be adequately visualized in a DDH particularly the inferior acetabulum which may be difficult to find in a Crowe IV. An anterior retractor is placed high on the

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Figure 25.35: Femoral head is dislocated. Note the mark on the femoral head

 

 

 

 

 

Total Hip Arthroplasty

 

Figure 25.36: Starting reamer preparing greater trochanter

 

Figure 25.37: Long curette passed down the canal to as

certain that the shaft has not been perforated

 

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.38: Reaming of femoral canal

 

 

 

Figure 25.39: Reaming length should be greater than femoral stem by an amount equal to anticipated shortening

Figure 25.40: Offset of femoral head is measured with straight reamer

 

 

 

 

in situ

 

Figure 25.41: Trial stem used to guide neck cut

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Total Hip Arthroplasty

 

Figure 25.42: Neck osteotomy

 

Figure 25.43: Using osteotome to complete osteotomy and remove femoral head

 

acetabulum as the acetabular bone will be thin or deficient anterior and anterosuperior (Fig. 25.44). Gelpie retractors are useful under the posterior capsule and anterior; do not use sharp retractors if the sciatic nerve is close or the capsule deficient (Figs 25.45 and 25.46). A retractor is used in the inferior acetabulum to define the lower part of the acetabulum (Fig. 25.47), this is essential to judge whether you are in the right starting position. If the floor of the acetabulum in undeveloped (Crowe IV) you need to ascertain the depth for safe

reaming. Use a drill bit and drill into the floor to assess the depth (Fig. 25.48).

The smallest reamer is used as a starting reamer being careful not to perforate the inner wall. Often the fat pad is still present even in Crowe IV hips. Subsequent reamers are used till you are close to the anterior and posterior walls (Fig. 25.49). It is at this stage you must decide if a micro cup is suitable (Figs 25.50 and 25.51). These cups go down to 38 or 40 but a 22 mm head must be used. Whether you use a micro cup depends on whether you have adequate coverage i.e. the superior wall supports the cup at the correct abduction angle of 45 degrees (lower if hard on hard bearing) (Fig. 25.52). The decision, if this is not possible, is to start to raise the joint line and to simultaneously contact anterior, superior and posterior walls without damaging them (Fig. 25.53). The anterior wall is delicate and may be deficient;

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.44: Anterior retractor should be placed high on the acetabulum as the acetabular bone is thin or deficient

 

 

 

Figure 25.45: Gelpie retractors. Pointed retractors are avoided when the sciatic nerve is close or capsule is deficient

 

Figure 25.46: Gelpie retractors are useful for capsular retraction

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Total Hip Arthroplasty

 

Figure 25.47: A retractor in the inferior acetabulum defines the lower extent

 

 

 

Figure 25.48: Drilling the floor can help assess the depth of the floor

 

Figure 25.49: Acetabulum is reamed till you are close to the anterior and posterior wall

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.50: Acetabular reamer for micro cups may be needed. Courtesy: Smith and Nephew

 

 

 

Figure 25.51: Micro cups go down to 38 or 40 mm size but a 22 mm head must be used. Courtesy: Smith and Nephew

 

Figure 25.52: A micro cup should be placed in anatomical location if there is adequate coverage for the cup

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Total Hip Arthroplasty

 

Figure 25.53: Raising the joint line can help contact anterior, superior and posterior walls

 

 

 

 

Figure 25.54: Postoperative radiograph of following bilateral THA for dysplastic hips. Note that the joint line has been raised on the left side

Figure 25.55: Femoral head autograph for dysplastic acetabulum—AP view

 

 

the reamers need to be controlled carefully with pressure towards the posterior wall. I am happy to raise the joint line 1 cm as long as the cup stays central (Fig. 25.54). If this is not possible then the conventional technique of femoral head autograft is used (Figs 25.55 and 25.56).

The technique of femoral head autograft is very important. The acetabulum is cleared of any remaining cartilage superiorly (Fig. 25.57). The femoral head is then orientated back into its original position (Fig. 25.58) and held with K wires. These should be divergent and away from where screws will be inserted (Fig. 25.59). Screws are then inserted along the lines of stress. I use 6.5 spongiosa screws, but may have to use smaller screws if the head is too small. Malleolar screws are useful but have a sharp tip and they should be used with care. They should not be completely threaded as you need to compress the head pelvis junction (Figs 25.60 and 25.61). When drilling for the screws, it is important to leave room for the cup as it is easy to have the screws too inferior (Fig. 25.59). It is useful to use

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Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.56: Lateral view showing femoral head autograft

 

 

 

Figure 25.57: Acetabulum is cleared of any remaining cartilage

 

 

 

 

Figure 25.58: Femoral head is oriented back into its original position and with K wires held

Figure 25.59: K wires should be divergent and away from where the screws will be inserted

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Total Hip Arthroplasty

 

washers on the screws to stop them cutting into the graft (Fig. 25.61). Once the screws are inserted a high speed burr is used to fashion the acetabular socket as a reamer may rip the graft off the pelvis (Fig. 25.62). The acetabular reamers are then used in a sequential manner. Going up 1mm at a time is safer to the graft than 2 mm increments. The cup is then inserted in the usual manner. It is safer to use peripheral or dome screws. I have never used a cemented socket with this construct (Figs 25.63 and 25.64).

 

 

 

Figure 25.60: Dysplastic hip— preoperative radiograph

Figure 25.61: Acetabulum reconstructed using femoral head autograft. Note that the screws are partially threaded to compress the head pelvis junction and washers are used to stop screws from cutting into the graft

Figure 25.62: A high speed burr is used to fashion the socket

 

 

 

Figure 25.63: Crowe IV hip Figure 25.64: Femoral shortening and femoral head autograft with cementless implant

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Figure 25.65: Severely dysplastic acetabulum

Figure 25.66: Overgrafting of acetabulum. The graft will fail if the fixation is inadequate

 

With femoral head autograft, it is very easy to overgraft the acetabulum (Figs 25.65 and 25.66). This does not seem to cause any problems; however, inadequate fixation would lead to early failure of the graft.

 

Femoral Tips and Tricks (WJMB)

The femur is also challenging in CDH and I have routinely used a modular prosthesis (Emperion–Smith and Nephew (Figs 25.67 and 25.68) or S-Rom De Puy). I have not needed to do femoral shortening in Crowe I and II, but if the reduction is too tight I do not hesitate to perform this procedure. In Crowe III and IV, I perform a subtrochanteric femoral shortening

 

 

 

Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.67: Modular prosthesis providing choice of anteversion.

Courtesy: Smith and Nephew

Figure 25.68: Modular prosthesis with variety of stem sleeve and neck options. Courtesy: Smith and Nephew

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Total Hip Arthroplasty

 

Figure 25.69: Femoral shortening long reaming of femur is required

Figure 25.70: Trial reduction is attempted and distance by which it is falling short is noted

 

if the preoperative templating shows that the leg will be lengthened more than 4 cm (Fig. 25.19) as lengthening more than this may lead to sciatic nerve problems.7,19 It is also important to consider femoral shortening if the reduction is too tight. The hip should be a reasonably easy reduction.

Some authors believe that if the anteversion is excessive, i.e. greater then 40 or 60 degrees that derotation osteotomy needs to be performed.6 This is not my preferred method and I have used only a modular prosthesis with no femoral failures at 10 years with Crowe III and IV.6

Femoral shortening has been recommended at the level of the trochanter or in the subtrochanteric area8 if a large amount of bone is taken from the proximal femur then the trochanter rides high and may be well above the center of rotation of the hip, which may cause poor mechanics, loss of abductor power and impingement (Fig. 25.24). The neck osteotomy should not be too low and femoral osteotomy should be below the level of the lesser trochanter.

Once the acetabulum is in situ, if the reduction is unacceptably tight or templating has shown lengthening of the leg to be unacceptable, subtrochanteric shortening should be performed.7

The femur is prepared for the trial. Reaming of the shaft should be longer than the prosthesis by more than the amount of shortening required, i.e. if 3 cm of shortening is required the femur should be reamed 4 to 5 cm longer (Fig. 25.69). The reaming distally should be 0.5 mm less than the manufacturer recommends, obtaining a tight fit distally and additional fixation will not be necessary. The prosthesis, which should be modular, is inserted. Trial reduction is attempted and the longitudinal distance from the center of the acetabulum to the center of the femoral head is measured (Fig. 25.70). This distance is the approximate amount of shortening. I shorten about 0.5 cm less than this distance. The vastus lateralis is raised off the femur anterior and posterior at the level below where the trochanteric sleeve is situated. There must be a few millimetres of bone below the sleeve. A longitudinal line is made on the femur longer then the amount to be shortened so that the orientation of the femur is not lost (Fig. 25.71). Then with the trial in situ two circumferential osteotomies are made parallel to each other using a reciprocating saw (Fig. 25.72). A longitudinal split is made between the two osteotomies with a small sharp osteotome and then a thicker one is

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Figure 25.71: A line is marked on the femur for the orientation of rotational alignment

Figure 25.72: With trial in situ, two parallel circumferential osteotomies are made using a reciprocating saw

 

 

 

Total Hip Replacement in Developmental Dysplasia of the Hip

 

Figure 25.73: A longitudinal splint is made between

the two osteotomies and fragments displaced Figure 25.74: The proximal femur and sleeve are impacted into the distal fragment

 

inserted to break the osteotomized segment off (Fig. 25.73). Then with the impactor the proximal femur and sleeve are compressed into the distal fragment. Self retaining bone holders or cerclarge wires should be used on the proximal and distal fragments to stop fracture (Fig. 25.74). Attempted reduction of the hip is undertaken. If it is too tight further bone is removed, when the reduction is achieved then autogenous graft from the acetabular reamers is placed around the osteotomy site (Figs 25.75 and 25.76).

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Total Hip Arthroplasty

 

Figure 25.75: Hip is reduced and the osteotomy site bone grafted

 

 

 

Figure 25.76: Contact at the osteotomy site with tight fit of the femoral stem distally

 

The anteversion is corrected by the stem in the sleeve and no derotation is required of either fragment. This type of shortening gives a stable and successful result without supplementary fixation.7

 

Results

 

The results of arthroplasty in dysplasia are widely published. However, the spectrum of severity seen in the disorder makes a comparison of techniques extremely difficult.

The most recent literature has demonstrated satisfactory outcomes in both cemented20

and cementless21 hip arthroplasty for DDH. Inadequate fit and fill of a nonmodular standard stem causes stem loosening, stem fracture due to distal fixation and nonunion of the osteotomy site due to insufficient torsional stability.22,23

The Senior Author (WJMB) have described favorable mid to long-term results of cementless total hip arthroplasties with subtrochanteric femoral shortening osteotomy and use of a modular stem.6 In this study we reviewed 28 hips in 22 patients with Crowe III to IV DDH and an average age of 45 years. The S-ROM stem (DePuy Orthopedics, Warsaw, Ind) was used and 6 patients required an average of 3.5cm of femoral shortening. The average preoperative Harris hip score was 37 (range, 19-69) and for those patients reaching 10 years postoperative, the average Harris hip score had improved to 81 (range, 45-99). The average SF12 score at 10 years was 41.64 for the physical component of the score (range, 21.59-58.95), and the average mental component SF12 score at 10 years was 54.03 (range, 38.65-61.40). The average WOMAC Score at 10 years was 23 (range, 2-50)

(Fig. 25.77).

Takao21 also used a modular cementless prosthesis. He evaluated 33 hips in 25 consecutive patients with Crowe IV dysplasia. The mean age was 60 and the average follow up was 8 years. The mean Merle d’Aubigne and Postel hip score improved from 9 to 16 points (out of a maximum of 18 points) which represents excellent outcomes. However, they did see dislocation in 2 patients and femoral loosening and subsidence in another.

Cemented stems can be used with femoral shortening (Figs 25.78 to 25.80). Charity20 evaluated cases involving the combined use of a subtrochanteric derotational femoral

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Figure 25.77: Results of cementless total hip arthroplasty for Crowe III to IV DDH using S-ROM stem in 28 hips (22 patients) subtrochanteric femoral osteotomy was done in 6 patients

 

 

 

 

 

Figure 25.78: Subtrochanteric femoral shortening with plate fixation. Courtesy: Dr Hugh English

 

Figure 25.79: Cemented femoral stem implanted in the patient shown in Figure 25.78. Courtesy: Dr Hugh English

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Figure 25.80: Postoperative radiograph cemented stems can be used with femoral shortening. Courtesy: Dr Hugh English

 

shortening osteotomy with a cemented Exeter stem. An osteotomy to achieve shortening and derotation of the proximal femur was maintained with a 3.5 mm compression plate while the implant was cemented into place. There were 15 patients (18 hips) with a mean age of 51 years (33 to 75) who had a Crowe IV dysplasia of the hip and were followed up for a mean of 9 years (52 to 168 months). The Charnley modification of the Merle D’Aubigné-Postel scores for pain, function and range of movement showed a statistically significant improvement from a mean of 2.4 (1 to 4), 2.3 (1 to 4), 3.4 (1 to 6) to 5.2 (3 to 6), 4.4 (3 to 6),

5.2 (4 to 6), respectively.

 

Conclusion                        

DDH is one of the most challenging problems the hip surgeon will face. Total hip replacement has shown itself to be an excellent and reliable surgical treatment in this most complex problem. The advent of modularity and micro cups has enhanced our ability to deal more expertly with this problem. Meticulous planning and surgical technique combined with patient education are the secrets to achieve reproducible and good or excellent results.

 

Illustrative                      Case                     

This patient was a 38-year-old female, with severe osteoarthritis of both hips secondary to DDH (Figs 25.81A to C). The right hip was 5mm shorter then the left. Bilateral simultaneous THR were performed and I deliberately the right leg tried to lengthen the right more to match leg lengths (Fig. 25.24). The reduction of the right hip was harder than the left hip. Post-operative abduction pillow and pillows under both knees were used. There was normal sciatic nerve function in both sides on the night of the operation.

The next day, the patient had a right sciatic nerve palsy with no dorsiflexion or plantarflexion of the foot. The patient was taken back to surgery that night and the nerve was explored. There was no bleeding or damage to the nerve but it was extremely tight with the knee in extension. I put the stem down further in the femur, but the hip was unstable. I changed the stem and did a femoral shortening (Figs 25.81D and E). The nerve began recovery the next day and the palsy completely resolved over 6 months. The patient still gets mild neurogenic pain down the leg.

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Figures 25.81A to C: Preoperative radiograph of 38 year old lady with bilateral DDH and secondary osteoarthritis. The right hip was 5 mm shorter than the left

 

Figure 25.81D: Bilateral THA with modular stem. Note that the limb lengths have been equalized. Patient developed sciatic nerve palsy on the right side

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Figure 25.81E: A femoral shortening with change of stem led to recovery of the sciatic nerve

 

References                       

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2. Jasty M, Anderson MJ, Harris WH. Total hip replacement for developmental dysplasia of the hip. Clin Orthop 1995;311:40.

3. Ganz R, Parvizi J, Beck M, Leunig M, Nötzli H, Siebenrock K. Femoroacetabular Impingement: A Cause for Osteoarthritis of the Hip. Clinical Orthopaedics and Related Research 2003;417:112-20.

4. Australian NJRR Annual Report 2005.p.29.

5. Paavilainen T. Total hip replacement for developmental dysplasia of the hip. Acta Orthop Scand 1997;68:77-84.

6. Biant LC, Bruce WJM, Assini JB, Walker PM, Walsh WR. Primary Total Hip Arthroplasty in Severe Developmental Dysplasia of the Hip. Ten-Year Results Using a Cementless Modular Stem. J Arthroplasty 2009;24(1):27-32.

7. Bruce WJM, Rizkallah, Kwon Y, Goldberg JA and Walsh WR. A new technique of subtrochanteric shortening in total hip arthroplasty. J Arthroplasty 2000;15(5):617-26.

8. Sugano N, Noble PC, Kamaric E, Salama JK, Ochi T, Tullos HS. The morphology of the femur in developmental dysplasia of the hip. J Bone Joint Surg 1998;80B:711-9.

9. Instructional Course Lectures; Volume 49, 2000, Chapter 3, page 24. Editor Charles T Price

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11. Hartofilakidis G, Stamos K, Karachalios T, Ioannidis TT, Zacharakis N. Congenital hip disease in adults. Classification of acetabular deficiencies and operative treatment with acetabuloplasty combined with total hip arthroplasty. J Bone and Joint Surg 1996;78-A:683-92.

12. Xenakis TA, Gelalis ID, Koukoubis TD, Soucacos PN, Vartziotis K, Kontoyiannis D, Tatsis C. Neglected congenital dislocation of the hip. Role of computed tomography and computer-aided design for total hip arthroplasty. J Arthroplasty 1996;11:893-8.

13. Schutzer SF, Harris WH. Trochanteric osteotomy for revision total hip arthroplasty: 97% union rate using a comprehensive approach. Clin Orthop 1988:227:172-83.

14. Glassman AH, Engh CA, Bobyn JD. A technique of extensile exposure for total hip arthroplasty. J Arthroplasty 1987;2:11-21.

15. Mercati E, Guary A, Myquel C. Une voie d’abord postero-externe de la hanche. Interet de la realization d’un “muscle digastrique.” J Chir 1972;103:499-504.

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16. Cameron HU, Botsford DJ, Park YS. Influence of the Crowe rating on the outcome of total hip arthroplasty in congenital hip dysplasia. J Arthroplasty 1996;11:582-7.

17. Kumar A, Shair AB. An extended iliofemoral approach for total arthroplasty in late congenital dislocation of the hip: A case report. Int Orthop 1997;21(4):265-6.

18. Harley JM, Wilkinson JA. Hip replacement for adults with unreduced congenital dislocation: A new surgical technique. J Bone Joint Surg 1987;69B:752-5.

    Total Hip Replacement in Developmental Dysplasia of the Hip

     

19. Garvin KL, Bowen MK, Salvati EA, Ranawat CS. Long-term results of total hip arthroplasty in congenital dislocation and dysplasia of the hip: A follow-up note. J Bone Joint Surg 1991;73A: 1348-54.

20. Charity JA, Tsiridis E, Sheeraz A, Howell JR, Hubble MJ, Timperley AJ, Gie GA. Treatment of Crowe IV high hip dysplasia with total hip replacement using the Exeter stem and shortening derotational subtrochanteric osteotomy. J Bone Joint Surg Br. 2011;93(1):34-8.

21. Masaki Takao, Kenji Ohzono, Takashi Nishii, Hidenobu Miki, Nobuo Nakamura and Nobuhiko Sugano J Bone Joint Surg Am. 2011;93:548-55.

22. Yasgur DJ, Stuchin SA, Adler EM, DiCesare PE. Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip. J Arthroplasty. 1997;12:880-8.

23. Park MS, Kim KH, Jeong WC. Transverse subtrochanteric shortening osteotomy in primary total hip arthroplasty for patients with severe hip developmental dysplasia. J Arthroplasty. 2007;22:1031-6.