|Year : 2017 | Volume
| Issue : 1 | Page : 23-28
Treatment of unstable hips in children with Ilizarov hip reconstruction: A retrospective analysis of six cases
Bipin Ghanghurde1, Mandar Agashe1, Tarush Rustagi2, Chasanal Rathod3, Rujuta Mehta1, Dominic D'Silva1, Alaric Aroojis1
1 Bai Jerbai Wadia Hospital for Children, Mumbai, Maharashtra, India
2 Indian Spinal Injuries Centre, New Delhi, India
3 Seven Hills Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||17-Feb-2017|
Bai Jerbai Wadia Hospital for Children, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction: Hip instability in older children and adolescents is mainly because of the loss of bone in the proximal femur or conditions that cause loss of the fulcrum. These may be related to infantile septic hip sequelae or neglected developmental dysplasia of the hip. Materials and Methods: We retrospectively analyzed six patients with hip instability treated by Ilizarov hip reconstruction from 2004 to 2007 at our institute. The mean age of the patients was 10 years (range 7–14 years). Results: The etiology was septic hip sequelae (Choi type IV) in four patients and neglected developmental dysplasia of hip in two patients. The fixator was kept for an average of 7 months (range 6–8 months). The average follow-up was 3 years. The visual analog score for pain improved from a preoperative mean of 8 to 2 postoperatively. The gait improved in all the patients and the leg length discrepancy improved from a preoperative mean of 5 to 1 cm postoperatively. All the limbs were aligned to a satisfactory level with the mean mechanical axis deviation of 3 mm (laterally) and pelvic mechanical axis of 90°. The Harris hip score improved from 41 preoperatively to 84 postoperatively (P < 0.0001). Conclusion: Ilizarov Hip Reconstruction is an excellent salvage procedure for adolescent patients with unstable hips, giving good results in the short-term.
Keywords: Ilizarov hip reconstruction, neglected developmental dysplasia of the hip, postseptic sequelae, unstable hip
|How to cite this article:|
Ghanghurde B, Agashe M, Rustagi T, Rathod C, Mehta R, D'Silva D, Aroojis A. Treatment of unstable hips in children with Ilizarov hip reconstruction: A retrospective analysis of six cases. Paediatr Orthop Relat Sci 2017;3:23-8
|How to cite this URL:|
Ghanghurde B, Agashe M, Rustagi T, Rathod C, Mehta R, D'Silva D, Aroojis A. Treatment of unstable hips in children with Ilizarov hip reconstruction: A retrospective analysis of six cases. Paediatr Orthop Relat Sci [serial online] 2017 [cited 2019 Dec 13];3:23-8. Available from: http://www.pors.co.in/text.asp?2017/3/1/23/200296
| Introduction|| |
The technique of pelvic support osteotomy was introduced way back in the 1930s and 1940s for the treatment of instability of the hip joint. It involved supporting the proximal femur against the lateral aspect of the pelvis usually after surgical excision of the head and neck of the femur.,,, This gave stability to the hip and improves the hip biomechanics by tensioning the abductors. It is a useful salvage procedure in cases wherein joint replacement or arthroplasty are not considered appropriate. This is especially true in postseptic hip sequelae and neglected developmental hip dysplasia in children and young adults. However, doing an isolated single valgus osteotomy has been cited to result in numerous problems. A large valgus angle may cause excessive knee valgus, fixed pelvic obliquity, and impingement pain when the patient adducts the lower extremity. Also the length discrepancy remains after the procedure. Ilizarov described a second distal osteotomy to overcome these problems and achieve parallelism of the limbs. In addition, the extension at the proximal level overcomes the compensatory lumbar lordosis because of hip flexion deformity. Lengthening is also performed through the distal osteotomy site that further levels the pelvis.
The main complaints of patients with unstable hips are pain, limb length inequality, and gait instability. The combined effect of length discrepancy and instability results in a short step length and a lateral shift of ground reaction force thus decreasing the maximum adduction moment of the hip on the affected side. This mechanical disturbance is corrected by the pelvic support osteotomy by using Ilizarov apparatus that not only supports and aligns the limb but also allows for lengthening at the distal osteotomy level.
The purpose of our study was to review our experience of this technique in unstable hips in adolescent and preadolescent children.
| Materials and Methods|| |
A retrospective review of six cases operated at our institution between 2004 and 2007 was done. Four of these had sequelae of septic arthritis (Choi type IV) and two had neglected developmental dysplasia of the hip. There were five boys and one girl with the mean age of 10 years (range 7–14 years). All the surgeries were performed by the senior author (AA). All the patients had instability as suggested by a positive telescopy test. The patients were clinically evaluated for pain using visual analog score (VAS) score, range of motion, presence of Trendelenburg’s sign, length discrepancy, and Harris hip score., Computed tomogram scan was done to evaluate the status of the acetabulum and the proximal femur.
Surgical planning and technique
The surgical planning of Ilizarov hip reconstruction (IHR) is critical for proper execution of the osteotomy and the frame construction. The preoperative planning and the determination of the osteotomy site were done as has been described by Paley. Radiographs that were taken included a parallel beam standing scanogram, cross-legged view in maximum adduction, and abduction view to determine the adduction contracture. Assessment was based on the shortening, mechanical axis deviation (MAD), and the lateral distal femoral angle (LDFA). The level of proximal osteotomy was determined at the level wherein the femoral shaft crossed the ischium on the cross-table view. The degree of valgus correction was determined by adding an overcorrection factor of 15° to the femoropelvic adduction angle measured on the standing anteroposterior view. Extension at the proximal osteotomy site was equal to the fixed flexion deformity of the hip. The level of the distal osteotomy that helps to align the limb and subsequent lengthening was determined from the intersection of the lines drawn perpendicular to the proximal pelvis passing through the proximal osteotomy site and distal line from the center of the ankle and the knee.
The patient was placed in the supine position on the radiolucent table. With the limb in maximum possible adduction, the site of proximal osteotomy was determined at the level of the ischial tuberosity under fluoroscopy. Three 6-mm Schanz pins were inserted in the proximal femur in the plane that was parallel to the horizontal plane of the pelvis and thus was oblique to the proximal femoral shaft. The pelvic arch was then connected to the Schanz pin in the same plane. Three more 6-mm Schanz pins were inserted distally perpendicular to the femoral shaft. These were then connected using a 5/8 ring. The proximal osteotomy was completed at the predetermined level between the arch and the 5/8 ring. The rotation of the limb was determined by the direction of the patella that was kept pointing forward throughout. The pelvic ring was then connected to the distal 5/8 ring. Three Schanz pins were then passed in the mid-shaft femur and connected by a full ring just below the determined level of distal osteotomy that was then connected to the 5/8 ring. A single 1.8-mm K wire and two Schanz pins were passed parallel to the knee joint at the supracondylar level. These were then connected to the distal full ring. The distal full ring was connected to the above rings using hinges on the posteromedial and posterolateral side. The distal osteotomy was then performed. The entire construct and the alignment were then finally checked under fluoroscopy.
Postoperatively, all patients underwent supervised daily physiotherapy including active and passive range of motion of the knee and ankle that was started 2 days after surgery by a physiotherapist. Partial weight bearing with two crutches was allowed during the distraction phase. Distraction at the distal osteotomy site was started 7–10 days postoperatively at a rate of 0.25 mm four times a day until the desired length was achieved. Patients were taught about pin tract care.
Evaluation and follow-up
The patients were assessed monthly till the time of fixator removal. During every follow-up, they were clinically and radiologically evaluated. Preoperative and postoperative parameters were compared in all the patients [Table 1]. The new center of the hip was determined for the postoperative measurement. This was taken as the point between one-third to one-half the distance lateral to the medial edge on the supporting edge of the proximal femoral segment.
|Table 1: Preoperative and postoperative, hip FFD, VAS score, and the Harris hip score|
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Distraction was continued till the desired length was achieved. After the completion of the distraction phase, the fixator was kept in the consolidation phase for at least 3 months till at least three cortices showed good signs of healing. Once satisfactory callus was seen on the radiographs, the patient was admitted for fixator removal. After removal of the fixator, a custom-made, functional femoral brace was applied. The patient was then asked to come for regular follow-up monthly for the first 6 months and then every six monthly thereafter. The patients were evaluated clinicoradiologically and checked for instability, Trendelenburg gait, and angular deformities. Pain was assessed using VAS. Functional assessment was done using Harris hip score.
The findings were entered using Microsoft Excel version 2007 and analyzed using SPSS version 16. Preoperative and postoperative data was analyzed using paired t test for all paired variables. The P < 0.05 was considered significant.
| Results|| |
During surgery, the mean level of the proximal osteotomy was 7 cm (5–9 cm) as measured from the greater trochanter tip. The mean valgus was 40° (35–60°) [[Figure 1]a–[Figure 1]c and [Figure 2]a–[Figure 2]c] and the extension averaged 10° (0–20°). The mean varus angulation at the distal osteotomy level was 10° (range 8–15°).
|Figure 1: (a) Long leg scanogram of a 10-year-old boy with untreated developmental dysplasia of the hip with 2.5 cm shortening. (b) Long leg scanogram of the boy with Ilizarov fixator in situ, showing a valgus angle of around 40° at the proximal osteotomy and lengthening osteotomy at the distal third of the femur. (c) Long leg scanogram of the same boy 1 year after removal of fixator with well-aligned mechanical axis, well-healed osteotomies, and equal leg lengths|
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|Figure 2: (a) Long leg scanogram of a 11-year-old boy with Choi type IV septic hip sequelae of the left side with severely unstable hip and significant limb length discrepancy. (b) Long leg scanogram of the same boy with Ilizarov fixator in situ showing a valgus angle of around 60° at the proximal osteotomy and lengthening osteotomy at the distal third of the femur. (c) Long leg scanogram of the boy 3 years after surgery after removal of external fixator with well-aligned mechanical axis, well-healed osteotomies, and almost equal limb lengths. The proximal osteotomy has remodeled to some extent|
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Two out of the six patients had high riding dislocations and four had a Choi type IV hip. The mean age was 10 years (7–14 years). The average duration in the frame was 6 months (5–10 months). The mean duration of follow-up was 48 months (24–60 months).
The flexion deformity and the range of motion of the hip significantly improved postoperatively. The most important outcome was the patient satisfaction for the pain relief that improved from the preoperative VAS score of 8 to 2 postoperatively (P < 0.05). The limb length discrepancy also significantly improved from 5 cm shortening to 1 cm postoperatively [Table 1]. The overall hip function as assessed by the Harris hip score showed improvement from 41 to 84 points that was statistically significant (P = 0.0001).
All the patients had a negative Trendelenburg gait. Radiographic parameters including the MAD and the LDFA also nearly normalized postsurgery.
Pin tract infection was the most common complication in four patients. This was successfully treated with antibiotics and dressing. One patient had to undergo a reosteotomy at the distal level because of early consolidation.
All patients developed some loss of knee flexion during fixator application, which improved in all but one patient after fixator removal with good physiotherapy. This stiffness was seen more toward the end of the distraction phase, and was more in those patients who had developed pin tract infections of the distal pins, which caused pain, thus making physiotherapy difficult. The knee range of motion progressively improved in the consolidation phase and once the pin tract infections came under control. The improvement continued after removal of the fixator and all but one patient regained their preoperative knee function until last follow-up. One patient had severe restriction of knee flexion even after fixator removal, in whom a quadricepsplasty had to be performed.
| Discussion|| |
The main complaints of the patient with an unstable hip are pain, shortening, vertical instability, and abductor lurch. Bombelli had showed that progressive instability leads to pain and lurch because of biomechanical instability.
Subtrochanteric pelvic support osteotomy has been described long time back by Hass in 1952. The main disadvantage with the valgus osteotomy was the excessive valgus that had to be given to provide stability. This resulted in proximal femoral abutment, restricted hip adduction movement, and problem related to knee valgus. The above complications were well described by Milch.,
Numerous procedures have been described to stabilize the hip. Choi et al. in their series of 13 hips could achieve satisfactory results in only four patients using procedures such as Pemberton osteotomy, trochanteric arthroplasty, and arthrodesis. The length discrepancy was corrected either by epiphysiodesis of the contra lateral extremity or tibia lengthening.
Similarly, Fabry and Meire concluded that procedures such as Salter’s osteotomy and trochanteric arthroplasty give poor and unpredictable results. Wopperer et al. in his study of eight patients concluded that reconstructive methods to contain the hip or trochanteric arthroplasty yielded poor results as compared to conservative treatment and suggested only correction of limb length discrepancy. In their large multicenter study, Betz et al. suggested against reconstructive surgeries of the hip but advised limb realignment in a functional position and correction of the length. Both these goals can be achieved through IHR.
Ilizarov method overcomes this problem by adding a distal osteotomy that allows for the limb realignment and lengthening., The mechanics of the hip are significantly improved and clinically proven by a negative Trendelenburg limp. This was observed in all the patients in our series postoperatively.
The other major outcome of this technique was the pain relief. This was attributed to the improvement in the hip mechanics, correction of the lumbar lordosis by correcting the hip flexion deformity, and absence of secondary knee valgus.
The level of proximal osteotomy in our series was 7 cm from the tip of the greater trochanter. Rozbruch et al. in their study had also noted an almost similar level of osteotomy. The level of this osteotomy is at the ischial tuberosity, as described by Schanz. This is to provide a soft tissue interposition between the femur and the pelvis at the proximal femur osteotomy site.
The valgus angulation that is required at the upper osteotomy level is of critical importance. It is recommended by various authors that some degree of overcorrection is necessary to offset the remodeling that may occur and thus negate the effect of the valgizing osteotomy. The amount of overcorrection required is a matter of great debate. Some authors have recommended a valgus overcorrection of around 15–25°,,,,, whereas according to Pafilas and Nayagam, this angle usually lies in the region of 30° to bring the postosteotomy angle of Milch as close to the recommended 240° as possible. This overcorrection produces an abduction contracture so that a pelvic tilt is created when the patient stands with parallel limbs. Similar degree of valgus angulation was noted in the series by Rozbruch et al. However, excessive valgus may cause lengthening and secondary knee valgus as described by Schanz in 1922.
The abduction contracture that was produced by the upper osteotomy was then corrected by the distal osteotomy. The lower osteotomy allows both limbs to be parallel, with the knee, ankle, and the pelvis horizontal. Rozbruch et al. had suggested the planning of this osteotomy by drawing two intersecting lines dropped from the pelvis traversing the proximal osteotomy and the mechanical axis of the tibia traced upward. Pafilas and Nayagam calculated this level using a mathematical formula that after correction would place the center of both the knee joints equidistant from the midline. Gradual lengthening at the second osteotomy corrects the length discrepancy. This prevents the development of the secondary knee valgus. All the patients had their medial proximal tibial angle (MPTA) and LDFA maintained at the final follow-up in our series.
An important component of IHR is the extension at the proximal osteotomy level that helps to improve the symptomatic lumbar lordosis. The hip range in the sagittal plane needs to be carefully assessed beforehand. Extension does help to reduce the pain component, but at the cost of reduced hip flexion range. This was observed in our patients in whom the average range of hip flexion reduced from 100 to 80° at follow-up. This compensation is however acceptable, in view of the painless standing posture that is attained. Similar reduction in hip flexion was also noted by other authors. The combination of decreased hip flexion and increase in abduction is directly related to the direction of the proximal osteotomy. The knee flexion range also reduced postoperatively in all the patients. This has been explained to occur because of the resulting quadriceps tightening secondary to femur lengthening. In one patient, no improvement could be attained even after quadricepsplasty. It was probably because of significant fibrosis of the muscles. The mean length discrepancy that remained at the final follow-up in our patients was 1 cm. This was comparable to other series in literature and proved that IHR was a valuable option to correct the LLD that is present in these patients. Rozbruch et al. in their series could attain the mean length discrepancy of 0.8 cm and El-Mowafi could attain equal length in all their patients.
| Conclusion|| |
To conclude, the Ilizarov method of hip reconstruction eliminates Trendelenburg gait, reduces shortening, and helps in improving the hip biomechanics. Thus, it is an excellent salvage procedure for adolescent patients with unstable hips with very good results in the short- term. A long-term study would however be needed to know how these hips fare in the years to come.
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Conflicts of interest
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[Figure 1], [Figure 2]