Capsular arthroplasty for neglected developmental dysplasia of hip

Abstract

Introduction:

Treatment of developmental dysplasia of hip (DDH) diagnosed after 10 years of age is extremely difficult because of the soft tissue and bone deformities. In this study, we evaluated short-term results of a single-stage procedure performed with surgical hip dislocation, femoral shortening and capsular arthroplasty.

Patients and Methods:

A retrospective review of charts of five patients with DDH, older than 10 years, who underwent capsular arthroplasty at Ghurki Trust Teaching Hospital between 2013 and 2015 was performed. Post-operative functional evaluation was performed using modified McKay’s scoring system and radiographic assessment using Severin’s scoring method at a minimum of 2-year follow-up.

Results:

We present results of five patients (six hips) with a mean age of 18.16 years. All patients had limping gait and International Hip dysplasia Institute classification (IHDI) class 4 hip dislocation. Harris hip score showed a significant improvement (53.13 vs 84.16; p = 0.0001). Femoral shortening of 2–2.5 cm was done. Additional shelf procedure was required in one patient. This patient persistently has post-operative hip subluxation. All patients had good to excellent outcomes according to McKay classification. Post-operative Severin classification was 1A in all patients. No case of avascular necrosis of the femoral head was noted during the follow-up.

Conclusion:

Capsular arthroplasty with subtrochanteric shortening is a useful procedure for neglected cases of DDH in patients older than 10 years.

Introduction

Developmental dysplasia of hip (DDH) is a common congenital anomaly of the hip joint, usually diagnosed early with the existing screening programme in western countries. ^1,2 Treatment algorithm varies according to patient’s age: for children under 6 months of age, treatment consists of brace; 6- to 18-month old children require closed or open surgical reduction and older children till 8 years of age require one of several described pelvic osteotomies. However, children older than 8 years have acetabular dysplasia which is unable to accommodate the femoral head upon hip reduction. ³

Treatment of DDH diagnosed after 10 years of age is extremely difficult because of the soft tissue and bone deformities. ^2,4 In the 20th century, joint preservation was the mainstay of surgical treatment. Options for joint preservation include techniques like pelvic osteotomy and capsular arthroplasty, femoral head–neck junction, osteochondroplasty and femoral head reduction osteotomy. ² With the advent of total hip replacement in the 1980s, hailed as the operation of century, joint preservation surgery was largely abandoned due to long immobilization period and frequent avascular necrosis of femoral head, suboptimal functional outcome compared to Total Hip replacement (THR) and subsequent need for joint replacement in future. ⁵

However, the survival curves of THR for patients younger than 50 years show a clear drop after 10 years with higher prevalence of dislocation, aseptic loosening, wear of the polyethylene and revision rates. ⁶ Increased interest in alternatives has invoked resurgence of joint preservation surgery. Colonna capsular arthroplasty, initially introduced in 1932, ⁷ consists of reaming of the original acetabulum and reduction of the femoral head covered with the joint capsule. Only a few articles on Colonna capsular arthroplasty have been published since 2000, with particular reference to no reports from Pakistan. We aimed to report our experience with Colonna procedure in children more than 10 years of age with neglected DDH with deformed acetabulum in which other hip preservation options like triple pelvic osteotomy, periacetabular osteotomy and chiari osteotomy were not possible.

Patients and methods

We retrospectively reviewed the medical records of all the patients who underwent Colonna interposition arthroplasty for neglected DDH in patients older than 10 years at Ghurki Trust Teaching Hospital between 2013 and July 2015. A total of six hips in five patients were identified. One patient had bilateral surgery. Indication for surgery was pain on weight bearing and limping gait in all patients. All patients had a minimum follow-up of 2 years. Pertinent details recorded were baseline demographics, preoperative Harris hip score, Trendelenburg sign, post-operative functional status and Harris hip score. Post-operative follow-up was achieved by review of notes of patient’s clinic visits at our hospital since the surgery.

Surgical technique

All patients were operated by the same surgeon. We used two incision techniques. First, the hip joint was opened through the Smith-Peterson approach. Key step to ensure success of this procedure was surgical hip dislocation, as described by Ganz et al., ⁵ which provided good exposure of acetabular cavity and, at the same time, preserved blood supply of the femoral head. Care must be taken to avoid trauma to the deep branch of the medial femoral circumflex artery, which is the main blood supply to the femoral head. The capsule was exposed between the piriformis and gluteus minimus muscles. Another key step was correct performance of capsulotomy which must be executed by an incising capsule as close as possible to the bone of acetabular rim, thereby preserving the maximum amount of capsule for later wrapping around the femoral head. Next, true acetabulum was identified and reamed with circular reamer up to the desired size. Femoral shortening was done through a separate lateral incision. We determined the amount of shortening by the distance of the bone overlap at the femoral osteotomy when the head was reduced and the knee fully extended; the maximal amount of shortening was 3 cm. Next, the head of femur was reduced into the reamed acetabulum with capsule interposed between the head and the acetabulum. Both wounds were closed with drain in place and a hip spica cast was given. Drains were removed on the first post-operative day and the patient was discharged on the second post-operative day. Hip spica cast was retained for 8 weeks. After the removal of the spica cast, range of movement and weight bearing was started and gradually progressed. At 1-year follow-up, hip score was recorded and compared with the preoperative Harris hip score.

Results

Table 1 illustrates preoperative and post-operative clinical and radiographic characteristics of patients. We present results of five patients (six hips) with a mean age of 18.16 years. All patients had limping gait and IHDI class 4 hip dislocation. Harris hip score showed a significant improvement (53.13 vs. 84.16; p = 0.0001). On the last follow-up, all patients with a preserved hip had a well centred, vital femoral head with a large and congruent joint space. No case of avascular necrosis of the femoral head was noted. Lateral centre-edge angle and acetabular roof angle were within the optimal range. Femoral shortening of 2–2.5 cm was done. Additional shelf procedure was required in one patient due to femoral head and acetabular size discrepancy. This patient persistently has post-operative hip subluxation and is planned for a total hip replacement in future. All patients had good to excellent outcomes according to McKay classification. Post-operative Severin classification was 1A in all patients (Figure 1 illustrates case study of a 13 year old girl with 2 years follow up).

Table 1.

Clinico-demographic profile of patients.

Parameter		Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Case 6
Age		13 years	16 years	16 years	17 years	22 years	25
Gender		Female	Female	Female	Female	Male	Female
Side		Right	Left	Bilateral right side	Bilateral left side	Right	Right
Previous surgery		No	No	No	No	No	No
Trendelenburg sign	Preoperative	Positive	Positive	Positive	Positive	Positive	Positive
	Post-operative	Negative	Positive	Negative	Negative	Negative	Negative
Limb length discrepancy	Preoperative	2 cm	3.5 cm	No	No	3 cm	2.5
	Post-operative	1 cm	0 cm	No	No	No	No
Limp	Preoperative	Positive	Positive	Positive	Positive	Positive	Positive
	Post-operative	Negative	Positive	Negative	Positive	Negative	Negative
IHDI class	Preoperative	Type 4	Type 4	Type 4	Type 4	Type4	Type 4
	Post-operative	Reduced	Type 1	Reduced	Reduced	Reduced	Reduced
Harris hip score	Preoperative	55	56	52	52	50	55
	Post-operative	84	76	88	85	84	88
Centre-edge angle	Preoperative	Hip dislocated	Hip dislocated	Hip dislocated	Hip dislocated	Hip dislocated	Hip dislocated
	Post-operative	27	32	34	34	33	34
Joint space		Congruent	Non-congruent	Congruent	Congruent	Congruent	Congruent
Additional procedure	Femoral shortening	2 cm	2 cm	2.5	2.5	2 cm	2.2 cm
	Shelf procedure	No	Yes	No	No	No	No
	Head size reduction	No	No	No	No	No	No
Menard–Shenton line		Intact	Broken	Intact	Intact	Intact	Intact
Head AVN		No	No	No	No	No	No
Severin grade		1A	1A	1A	1A	1A	1A
McKay criteria		Excellent	Good	Excellent	Good	Excellent	Excellent

AVN: avascular necrosis.

Figure 1.

Case presentation of 13 year old girl with right sided neglected developmental dysplasia of hip (a) Preoperative X-ray. (b) Immediate post-operative X-rays. (c) and (d) Follow-up X-rays at 21 months. (e) No post-operative limb length discrepancy. (f) Post-operative hip flexion. (g) Post-operative hip abduction. (h) Post-operative hip adduction.

Discussion

DDH is usually diagnosed early with the existing screening programme in western countries. ^1,2 However, in developing countries like Pakistan with low literacy rate, poverty and tendency towards alternative medicine, including traditional and religious healers, DDH diagnosed in adolescence is still a common occurrence. The complexity of situation is compounded by lack of access to health facilities due to self-financed healthcare system and also due to lack of expertise in this complex entity.

Although treatment of late neglected cases of DDH may have gravitated towards joint replacement in western countries, joint preservation surgery still has a role in developing countries like Pakistan, even for the sake of delaying last resort to THR. THR is an expensive modality in self-financed healthcare system. Moreover, it is technically challenging in neglected DDH patients due to bony and soft tissue abnormalities. ^2,4 The outcome of THR in patients 20 years of age at surgery is far from promising, with 25% acetabular loosening after 6 years ⁸ and 30% revision, as well as a high prevalence of eccentric wear after 13 years. ⁹ It has also been proven that subsequent THR after capsular arthroplasty is technically easier and safer compared to a primary prosthesis in a dislocated hip and false acetabulum. ⁵

Capsular arthroplasty is a method of joint reconstruction for the dislocated hip. The capsule heals into the cancellous bone of the newly reamed acetabulum and turns into fibrocartilage. ⁵ This technique, first described by Codivilla ¹⁰ and later by Groves ¹¹ and Colonna, ⁷ has once again been modified and popularized by Ganz et al. ⁵ It is a technically demanding procedure due to deformities of the proximal femur including bigger elliptical femoral head, excessively anteverted femoral neck, increased neck shaft angle and posteriorly displaced greater trochanter. These bony anomalies are accompanied with soft tissue changes such as transverse orientation of the abductor muscles, shortening of the hamstring and sciatic nerve. ² Review of literature shows results varying from well-functioning hips for decades ^12,13 to reports of frequent failures, ^{14 –16} mainly due to femoral head necrosis (up to 50%), ^12,16 joint stiffness (up to 30%) ^13,17 and deficient coverage and redislocation (up to 15%). ^12,17

Ganz et al.’s ⁵ modification involves surgical hip dislocation followed by acetabular reaming and capsulotomy via a T-shaped incision as close to the acetabular rim as possible. A subtrochanteric osteotomy and femoral shortening was performed in case of difficulty in reducing femoral head. Later the capsule was wrapped around the femoral head, derotated to get a femoral neck anteversion of 15–20 and reduction into acetabulum done. With this technique, osteonecrosis of the femoral head, joint stiffness and secondary subluxation can be reduced. Ganz et al. ⁵ retrospectively reported the results of their technique in nine patients, aged 13–25 years, after a mean follow-up of 7.5 years. The mean Harris hip score was 84 (n = 7) at the last follow-up and one patient had THR after 27 years.

Limitations of our study include small sample size and short follow-up. Longevity of reconstruction and need for additional procedures cannot be established. Moreover, this surgery is infrequent, requires special expertise and will achieve the best results in experienced hands.

Conclusion

We suggest that capsular arthroplasty with subtrochanteric shortening is a useful procedure for neglected cases of DDH in patients older than 10 years in which acetabulum is so deformed that other operations like triple pelvic osteotomy, periacetabular osteotomy and chiari osteotomy are not possible.