A Study on the Complications of Surgical Treatment for Bilateral Developmental Dysplasia of the Hip and A Comparison of Two Osteotomy Techniques

Objective: This study aims to present a review about complications of surgical treatment of Developmental Dysplasia of the Hip and comparing the kinds and ratios of two osteotomy technique (Salter Innominate Osteotomy and Pemberton Pericapsular Osteotomy). Materials and Methods: Fifty-seven patients of 126 that had bilateral developmental dysplasia of the hip are the case series that had undewent to Salter Innominate Osteotomy for one hip and Pemberton Pericapsular Osteotomy for other hip by one surgeon in one stage. Results: Avascular Necrosis ratio was 19.29% on hips with Salter Innominate Osteotomy, and 8.77% on hips with Pemberton Pericapsular Osteotomy. Salter Innominate Osteotomy made lower limb discrepency with 0.47 cm mean in all patients. There were 17 general complications on hips with Salter Innominate Osteotomy (SIO) (14.91%) and 9 general complications on hip with Pemberton Pericapsular Osteotomy (PPO) (7.89%). As looking for general complications, SIO/PPO ratio were 1.8 (17/9). Conclusion: By the comparing two osteotomy technique for complication ratios, SIO had two-fold of complications than PPO. SIO had 65% more complications as to PPO.


Introduction
Complications that can accompany surgical treatment of developmental dysplasia of the hip (DDH) include subluxation-redislocation, K-wire migration, implant loss, avascular necrosis (AVN) of the femoral head, lower limb discrepancy, infection, joint stiffness, malunion or nonunion of the osteotomy line, graft problems, lateralization defects of the femoral head, and sciatic nerve damage.
Complications of Salter innominate osteotomy (SIO) include early postoperative complications, sciatic nerve damage, K-wire migration, K-wire luxation/breakage, medial displacement of the distal fragment, resubluxation/redislocation, correction loss by graft breakage, supracondylar femoral fracture, and avascular necrosis of the femoral head.Additionally, lower limb discrepancy can be observed especially with unilateral DDH.
Complications of Pemberton pericapsular osteotomy (PPO) include avascular necrosis of the femoral head, early closing of Y cartilage, and damage to the ephysial center.

Materials and Methods
This case series consisted of the 57 out of 126 patients who had bilateral developmental dysplasia of the hip between 1993 and 2010 in the Orthopedia & Traumatology clinic.Given the correct indications, one-stage procedures were applied by a single surgeon, Salter innominate osteotomy for one hip and Pemberton pericapsular osteotomy for the other hip.
Retrospective archive searches were conducted for these 57 patients, and preoperative x-rays and anamnesis results were obtained.Intraoperative records were confirmed for each case.The patients were examined at their last clinical examination, and postoperative x-rays were taken.The patients were evaluated by x-ray and computerized tomography for hip and pelvic biomechanics.

Results
With SIO, 11 hips developed AVN, whereas 5 hips developed AVN with PPO.The proportion of AVN complications with SIO versus PPO was 2/1 (Table 1, 2) (Figure 1).The frequency of AVN was 19.29% for hips with SIO and 8.77% for hips with PPO (Table 3).
Lower limb discrepancy, which entails a risk for pelvic biomechanics, was found to be absent from 4 patients.Three patients' hips with PPO had a mean discrepancy of 0.66 cm, and 51 patients' hips with SIO had a mean discrepancy of 0.49 cm.The mean lower limb discrepancy in all patients with SIO was 0.47 cm (Figure 2).
There was one hip with growth retardation, 12 hips with necrosis, 6 hips with coxa magna, 3 hips with coxa plana, and 2 hips with short neck+coxa vara (bilateral).Premature physial closing were found on 7 hips (3 bilateral hips, 1 hip with SIO), and there was no cartilage arrest.Obturator foramens narrowing occurred in 5 hips (3 hips with SIO, 2 hips with PPO) (Figure 3).There was one redislocation of a hip with SIO, and resubluxation was performed on a hip with SIO (Figure 4).One hip with SIO had joint stiffness (1.75%).There was no sciatic, femoral, or peroneal nerve damage in this case series.One patient had a supracondylar femoral fracture, and three patients had a femoral fissure.Two patients had superficial infections in the first month after the operation.There were 17 general complications in hips with SIO (14.91%) and 9 general complications on hips with PPO (7.89%) (Table 4, 5).Regarding general complications, the SIO/PPO ratio was 1.8 (17/9) (Tables 6-9).

Discussion
AVN is a permanent and significant complication of surgical treatment for DDH.According to Salter, AVN is due to open reduction, not osteotomy.Damage from the posterior resection of the capsule and circumflex arteries affects the ossification center and growth plate.In earlier stages, it is defined as epiphisytis.Later, vascular damage progresses in femoral-proximal areas and in the acetabulum.Kalamchi and MacEwen classified these vascular changes.Kalamchi reported the frequency of AVN as between 0 and 73%.[1].Barrett reported the frequency of AVN as 6% [2].Ferre reported it as 2% [3].AVN was 63.3% in Gulman's series, and 34.6% of the series were types 2, 3 and 4. Hajdar reported AVN as 8.1% [4].
McKay reported AVN as 15% [5].Mergen reported AVN as 24% [6].Dennis-Peterson reported AVN as 11.2% in a series with 143 patients [7].Morin reported AVN as 3.3% in primary cases and 27.8% in secondary cases.Klisic offered a combination of open reduction and femoral shortening [8].Salter-Dubos reported 6.8% for hips with combination open reduction and acetabuloplasty and 30% for hips with an additional intertrochanteric osteotomy [9].Tonnis reported AVN as 10.3% for hips with open reduction plus acetabuloplasty and 22.2% for hips with an additional intertrochanteric osteotomy.And emphasized increased AVN in hips with the Lange and Lorenz positions [10].Baki et al. studied this subject and found that tenotomy decreased the frequency of AVN [11].AVN occurs after SIO at between 1.2% and 63.4% in the world literature [12].In the Turkish literature, AVN after SIO is reported to be between 1.8% and 29.3% [13].In the etiology of AVN, there are two factors: blockage of the extracapsular vessels by immobilization and mechanical pressure.
Pemberton reported 15 cases of coxa plana among 300 patients in his series [14].Gordon et al. reported no AVN in their series [15].Hellinger and Schmidt reported no AVN and offered intertrochanteric osteotomy to prevent AVN [16].Faciszewski et al. reported no AVN after PPO [17].In a case series of 14 hips with PPO, Hamzaoglu et al. reported one hip with AVN, femoral shortening, derotation and varization [18].
Lower limb discrepancy can be observed for hips with unilateral DDH after SIO.If the extremities are equal or if the ipsilateral extremity is longer, significant discrepancy occurs after SIO.Preventive medial and posterior displacement of the distal fragment of the osteotomy line is technically challenging.This displacement causes inappropriate rotation and insufficient femoral head covering.Kalamchi established a modified osteotomy technique for lower limb discrepancy [19].Hall offered a trapezoidal bone graft technique to obtain equality.Hajdar reported one patient with a lower limb discrepancy of 2.7% [4].
Superficial infection is another complication in the earlier postoperative stages that generally derives from perioperative or postoperative asepsis.Barrett reported one (1.47%)superficial infection [2].Hajdar reported one (8%), Mergen et al. reported 3%, Morin reported 9.4%, and Roth reported 14% [4,6,22,24].Salter reported 1.5% in the primary group and 3.2% in the secondary group [23].Mergen reported one deep infection (1%) [25].Peterson reported one deep infection (0.7%) [7].Teuffer reported 4 wound detachments (7.5%), and healing occurred within 30 days [25].Salter cited 2.5% in the secondary group [23].Hellinger et al. reported 4 deep infections and 7 superficial infections in 379 cases [16].In their case series of 14 patients who received Pemberton pericapsular osteotomy, Hamzaoğlu et al. reported one superficial infection with shortening, derotation and osteotomy varization [18].Gordon et al. reported no infection in their series.In our case series, 2 patients (3.5%) had superficial infections.Joint stiffness is another symptomatic complication that affects a patient's individual daily life in the earlier stages.Karakas emphasized the importance of hip joint functionality.Early recovery of range of motion (ROM) is a basic element of successful surgical hip joint treatment [26].Tachdjian stated that excess pressure on the hip joint after SIO is a reason for joint stiffness [27].Ege stated that joint stiffness can be prevented by treating tissue with increased care [28].Pemberton reported 8% joint stiffness and 8% less ROM in his series [29].Herold stated that stable reduction, shorter immobilization   and earlier rehabilitation all help to prevent joint stiffness.
Sciatic nerve damage has been reported as a complication after SIO [35].Salter did not report this complication for his series.Supracondylar and intertrochanteric femoral fractures are observed rarely after reduction and during rehabilitation.Skeletal traction before the operation and long immobilization times aggravate osteoporosis and increase fracture risk.Ege reported the frequency of supracondylar femoral fractures as 1.6%-7.8%;Crellin reported 7.6%; Hajdar reported 5.4%; Peterson reported 0.7% ; Morin reported 3.3%; and Roth reported 2% [4,7,20,22,24].Salter reported 6.4% in the primary group and 5.7% in the secondary group [23].Peterson observed sliding of the proximal femoral physis in one case in his report (0.6%) [7].In a series of 68 patients, Barrett reported 3 cases of loss of graft fixation (4.4%) and 1 late union (1.5%) [2].
In contrast to prevailing thought, Pemberton reported that his technique could be successful even in the presence of coxa magna or a narrow acetabulum [14].However, Tachdjian stated that PPO is contraindicated if the femoral head is   smaller than the acetabulum.Degenerative osteoarthritis of the hips with residual subluxation and/or acetabular dysplasia after insufficient treatment has been reported to occur in 1%-48% patients [36].Avascular necrosis increases both deformity and osteoarthritis.Pemberton thought he could wait for 20-30 years to say whether there is an increased risk of premature osteoarthritis [14].Triradiate cartilage damage and epiphysial arrest after PPO is theoretically possible.However, there are no reports about this complication type.
In our case series, neither triradiate cartilage damage nor epyphysial arrest occurred.A comparison of these two osteotomy techniques revealed that the rate of complications is two-fold higher with SIO than PPO.SIO entailed 65% more complications than did PPO.