Adolescent and Young Adult Hip Dysplasia

David D. Spence, Derek M. Kelly, Marc J. Mihalko and James L. Guyton

Disclosures

Curr Orthop Pract. 2013;24(6):567-575. 

In This Article

Treatment

Conservative Treatment

In adolescents or young adults with mild hip dysplasia or in those in whom hip dysplasia has already caused so much damage that the only option would be a total hip arthroplasty, a trial of conservative treatment may be worthwhile. Ziegler et al.[24] in a metaanalysis found insufficient evidence in the literature (1975–2007) that mild or moderate developmental dysplasia of the hip at skeletal maturity is associated with the onset of osteoarthritis. However, hips with mild disease must be closely monitored for progression because early correction of malformation may delay or may even prevent the onset of osteoarthritis.[3,6,7,19] If conservative treatment is feasible, nonsteroidal antiinflammatory medication, activity modification, and physical therapy to include stretching and abductor strengthening are prescribed. Injection of corticosteroids also may help to alleviate pain by reducing inflammation; however, repeated use can weaken tendons and cartilage. Injection of the hip with lidocaine is a useful tool in assessing whether or not the etiology of a patient's pain is intraarticular. This is not a realiable diagnostic aide, however, in determining whether or not surgery is necessary.[25]

Surgical Treatment

Surgery usually is necessary in moderate to severe adult or adolescent hip dysplasia to restore proper hip biomechanics and stability and delay the onset of osteoarthritis. Joint preserving techniques and soft-tissue procedures accomplish these goals to varying degrees, and the type and success of treatment depend on the severity, hip joint morphology, degree of soft-tissue involvement, and whether or not osteoarthritis is already present.[26] Reducing stress on the acetabular rim and restoring joint stability without causing impingement or further joint incongruity are the aims of bony procedures. It has been demonstrated that labral tears can be caused by structural hip abnormalities, including those that are very mild, and are often precursors of osteoarthritis.[14] Repair of labral tears, if present, can be done open or arthroscopically, but any underlying structural abnormality should be treated at the time of surgery to lower the risk of recurrence. Hip arthroscopy is an important adjunct in treatment of intraarticular pathology and is safe to use in this population with a low complication rate;[27] however, hip arthroscopy should not be performed alone in moderate to severe hip dysplasia because it can further destabilize the joint and lead to rapid progression of joint degeneration.[28]

Periacetabular Osteotomy (Bernese Technique)

Periacetabular osteotomy restores the normal anatomy of the hip by repositioning the acetabulum over the femoral head. A proximal femoral osteotomy also may be necessary if abnormal proximal femoral geometry exists.[29] Patients must meet the following criteria for the best outcomes: (1) must have a closed triradiate cartilage, (2) have symptomatic acetabular dysplasia with minimal osteoarthritis, and (3) have a center-edge angle of less than 181. Patients with severe cartilage damage or end-state arthritis are not good candidates for the procedure. They will require initial conservative treatment for as long as possible before total hip replacement.[28] Further contraindications are substantial loss of joint congruity and low values on dGEMRIC as noted by Matheney et al.[7] If the triradiate cartilage is open then either another acetabular reorientation procedure such as a triple osteotomy should be considered or one can wait until the triradiate closes before performing the periacetabular osteotomy. In 1988, Ganz et al.[30] introduced a triplanar periacetabular osteotomy (Bernese osteotomy) to correct the congruency of the acetabulum and improve containment of the femoral head. The procedure involves a partial osteotomy of the anterior portion of the ischium, complete osteotomy of the pubic ramus, a chevron-shaped supraacetabular osteotomy, and a retroacetabular osteotomy, avoiding damage to the vascular supply to the periacetabular fragment (Figures 5 and 6).

Figure 5.

Bernese osteotomy. Reprinted with permission from: Steppacher et al.6 Clin Orthop Relat Res. 2008; 466:1633–1644.

Figure 6.

Thirteen-year-old patient with bilateral adolescent hip dysplasia (A) treated with periacetabular osteotomy (B).

Ganz et al.[30] originally described exposure of the inner and outer tables of the ilium through a Smith-Petersen approach, stripping the abductors to expose the posterior acetabular column; however, later Murphy and Millis[31] modified the approach by using a bikini-type incision and by making the osteotomy on the inner surface of the pelvis sparing the abductors. Lara et al.[32] described a further modification that spares the rectus muscle, allowing patients to return to activity quicker. Advantages of the Bernese periacetabular osteotomy for adolescents and adults with hip dysplasia include: (1) only one incision is required; (2) a large amount of correction can be obtained in all directions; (3) vascular supply to the acetabulum is preserved; (4) immediate postoperative mobilization is possible because the posterior column is left intact; (5) the true shape of the pelvis is preserved, which is especially important in women when considering child bearing; and (6) it allows a trochanteric osteotomy to be performed if necessary.[29] Technique:

  • Exposure can be obtained through a Smith-Petersen approach as originally described by Ganz et al.[30] or a bikini-type incision that follows the inguinal crease medially as described by Murphy and Mills.[31] The bikini incision is cosmetically more pleasing and can be used in thin patients; however, a standard Smith-Petersen incision provides better access to the hip joint for repair of the labrum and osteochondroplasty of the femur .

  • After dissection, the hip is placed in 451 of flexion and slight abduction. The technique described by Matheney et al.[7] preserves the abductors. Osteotomy of the anterior portion of the ischium is carried out followed by osteotomy of the superior pubic ramus.

  • At this point an arthrotomy can be performed to inspect the intracapsular space for a labral tear, cam lesion, or loose bodies. The arthrotomy is closed with simple interrupted absorbable sutures.

  • Next, a supraacetabular iliac osteotomy is done and a Schanz screw inserted into the acetabular fragment well above the dome of the acetabulum. The cut at the posterosuperior corner of the periactabular osteotomy is the starting point of the posterior-column osteotomy, which is performed next.

  • The acetabular fragment is mobilized and the necessary repositioning of the acetabulum is performed to obtain adequate anterior or lateral coverage.

  • After provisional fixation, an anteroposterior radiograph of the pelvis is obtained to evaluate the correction. Radiographic landmarks such as acetabular roof orientation, head-to-ilioischial line position, anterior and lateral positioning of the acetabular rim, Shenton's line, and radiographic teardrop position are used to determine correct alignment.

  • The acetabular fragment is further medialized at this point if necessary to recreate the proper position of the femoral head in relation to the medial aspect of the pelvis.

  • Fixation is accomplished with 3.5 or 4.5-mm cortical screws.

Proximal Femoral Osteotomy: In patients with severe deformity involving the proximal femur, a combined acetabular osteotomy and proximal femoral osteotomy is necessary to improve congruency and femoral head containment and coverage. However, patients with severe painful limited range of hip motion, moderate osteoarthritis, and older age may not be candidates for a combined procedure. The most frequent indication for an additional proximal femoral osteotomy is a hip with abnormal femoral anatomy that has had a previous intertrochanteric osteotomy. Recently, several other useful proximal femoral osteotomies at the head and neck level have been introduced.[33]

Postoperative Care: Thrombophrophylaxis is recommended for 6–8wk after surgery, if the patient is older than 16 years. Nonsteroidal antiinflammatory drugs are avoided. Partial weightbearing with assistance is allowed with supervision the first day after surgery, and the patient may sit on the second day. Range of motion is limited to 901 flexion, 101 extension, and 101 adduction for the first 6 wk. Partial weightbearing is progressed to full over 6–8 wk, and when radiographic healing is obvious and abductor strength has returned, the patient may be full weight bearing. Resistive exercises are begun at 3 mo.[29]

Outcomes of Bernese Periacetabular Osteotomy: The overall complication rate with the Bernese periacetabular osteotomy has been reported to range from 3.6–10%.[8,33,34] The technique has a steep learning curve, and reports indicate that complications occur more frequently earlier in the learning curve.[8,33–35] Intraarticular extension of the osteotomy, inadequate or excessive acetabular coverage, femoroacetabular impingement from overcorrection, femoral or sciatic nerve palsy, disruption of the posterior column, osteonecrosis, hardware-related problems, nonunion, heterotopic ossification, hematoma, postoperative acetabular fragment migration, infection, and, most recently, stress fracture of the inferior pubic ramus are possible complications.[8,30,34,36] Although the risk of sciatic nerve damage is small in this procedure, retraction of the soft-tissue during the procedure can cause injury. The lateral femoral cutaneous nerve is likewise at risk from stretching during retraction and has been reported in 1.5–38% of patients.[34] The obturator nerve is at risk during osteotomy of the pubic ramus.

Steppacher et al.[6] followed 58 patients (mean age 29 years) for 20 years after a Bernese osteotomy. Forty-one of 58 hips were preserved at last follow-up. Overall, at 20-year followup the mean Merle d'Aubigné and Postel score (numerical clinical grade of pain, walking ability, and range of motion; excellent 18, poor <13) was lower than at 10 years and was closer to the preoperative score. They identified advanced age, low preoperative Merle d'Aubigné and Postel score, positive anterior impingement test, preoperative signs of osteoarthritis, a postoperative extrusion index less than 20%, a preoperative limp, and femoral impingement from overcorrection as predictors of poor outcomes. They noted that in patients younger than 30 years, with little or no osteoarthritis, the Bernese osteotomy can maintain a natural hip for at least 19 years.

Matheney et al.[7] found 76% of hips preserved at an average of 9 years, with an average Western Ontario and McMaster Universities pain score (0–20) of 2.4. Failure was noted in 24% of hips, with a postoperative pain score of more than 10. Age older than 35 years and poor or fair joint congruity before surgery were predictors of failure. They noted that although the Bernese osteotomy is an effective treatment for hip dysplasia, complications may occur in up to 15% of patients. Complications noted in their study included transient peroneal nerve palsy, wound hematoma, infection, nonunion, heterotopic ossification, and an intrapelvic abscess in one patient.

Sucato et al.[37] examined functional outcomes as concerns gait and hip strength after the Bernese osteotomy in 23 patients with adolescent onset hip dysplasia. Although the osteotomy improved radiographic parameters and improved functional outcome, as previous studies had shown, hip flexion strength was less at 6mo follow-up than preoperative values, although it increased by 1 year followup to slightly over preoperative levels. They cited compromise of the psoas muscle and rectus tendon as a possible reason and recommended leaving the rectus tendon attached to the anterior inferior iliac spine during the surgical procedure and ensuring that the iliopsoas tendon does not drop into the osteotomy gap of the superior pubic ramus. In addition, they emphasized that physical therapy postoperatively should focus more on hip flexion strengthening and suggested a preoperative strengthening program as well.

De La Rocha et al.[38] evaluated outcomes of the Bernese osteotomy in patients with hip dysplasia who had had previous surgery of the pelvis. They reported that the procedure was effective in correcting radiographic features and function, and patients generally returned to their baseline gait pattern within 1 year of surgery regardless of whether or not they had pelvic surgery; however, in patients who had previous pelvic surgery, abductor weakness and decreased flexion strength were noted 1 year after the Bernese osteotomy.

Triple Osteotomy

For patients with an open triradiate cartilate, a triple osteotomy as described by Steel allows repositioning of the acetabulum when this is not possible using other osteotomies. To be successful, the articular surfaces must be congruous once the acetabulum has been redirected to produce a painless, functional hip, with a normal gait.[39]

Chiari and Shelf Osteotomies

In patients in whom femoral head repositioning into the acetabulum is not possible or in patients with painfully subluxated hips and signs of osteoarthritis, salvage procedures are available. These include the Chiari and Shelf procedures. The Chiari osteotomy is a capsular arthroplasty that displaces the hip nearer to the midline, improving hip biomechanics. The Shelf osteotomy is used in hips when the femoral head and acetabulum are malformed but are still congruent. Redirectional osteotomies would cause incongruity in these cases.

Total Hip Replacement

Total hip replacement is reserved for older patients or patients in whom the hip has marked degenerative changes or cannot be salvaged by other means.[29] When to proceed with total hip arthroplasty in an adult with hip dysplasia depends on the amount of dysplasia, the grade of osteoarthritis, the severity of functional impairment, and the amount of pain present. Generally, results are good; however, the risk of complications increases in patients with a small acetabulum or femur, depleted bone stock, excessive femoral or acetabular version, leg-length discrepancy, or in patients who have had previous corrective surgery. Several classification systems have been developed in an attempt to correlate the pathology present with anticipated complications.[17,40–42] Generally, total hip arthroplasty in developmental hip dysplasia in adult patients has a favorable outcome;[43–46] however, results may be less satisfactory depending on the severity of deformity, surgeon experience, and type of implant used.[17]

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