Safely Reducing the Incidence of Contralateral Slipped Capital Femoral Epiphysis: Results of a Prospectively Implemented Prophylactic Fixation Protocol Using the Posterior Sloping Angle.

BACKGROUND: Bilateral slipped capital femoral epiphysis (SCFE) is common. The management of the contralateral hip in unilateral SCFE remains controversial. The aim of this study was to report on the clinical outcomes using a posterior sloping angle (PSA) threshold of 14.5 degrees for prophylactic fixation in preventing contralateral SCFE. METHODS: Having previously established through a retrospective study that PSA was predictive of future slip, the authors put in place a protocol where patients with unilateral SCFE who had a PSA ≥14.5 degrees on the contralateral side were offered prophylactic fixation. Those with unilateral SCFE presenting between January 2008 and December 2018 with a minimum of 12-month follow-up were included. Patients with renal or endocrine disorders were excluded. Primary outcomes were the number of slips prevented, the number needed to treat, and the complication rate. RESULTS: Of the 219 patients who were included, 114 (52.1%) underwent prophylactic fixation.A PSA threshold of 14.5 degrees prevented 77% of subsequent slips with a number needed to treat of 2.4 in our population. There were no cases of chondrolysis, avascular necrosis, or periprosthetic fracture associated with prophylactic pinning. CONCLUSIONS: Prophylactic fixation using a PSA of 14.5 degrees is safe, decreases unnecessary intervention, and reduces 77% of subsequent SCFE. The PSA can increase over time and the authors recommend that the protocol be applied for the duration of follow-up. LEVEL OF EVIDENCE: Level III.

Increased Hip Intracapsular Pressure Decreases Perfusion of the Capital Femoral Epiphysis in a Skeletally Immature Porcine Model.

BACKGROUND: Increased intracapsular hip pressure is thought to be one of the possible etiologies of femoral head avascular necrosis after intra-articular proximal femoral fractures or acute slipped capital femoral epiphysis. The purpose of this study was to evaluate the relationship between intra-articular hip pressure (IAP) and epiphyseal perfusion pressure (EPP), and its dependency on skeletal maturity using a porcine model. METHODS: Seven female Yorkshire-hybrid pigs were used to study the direct relationship between IAP and EPP. A needle inserted into the capsule provided both IAP monitoring and saline infiltration until IAP was above mean arterial pressure (MAP). Video simultaneously documented IAP, EPP, MAP. Parameters for all trials in each hip were averaged and compared between the 2 age groups. Significance was P<0.05. RESULTS: Four young hips (in pigs 10.3±1.0 wk, 27.4±2.0 kg) and 5 older hips (21.1±0.1 wk, 89.4±7.1 kg) were studied. There was no significant difference in the MAP (50.0±11.8 and 55.5±7.0 mm Hg respectively, P=0.411) between the 2 age groups. In the older hips, biphasic EPP persisted despite increasing IAP to an average of 177 mm Hg over MAP. In the young pigs, the biphasic EPP waveform ceased with increased IAP to an average of 28 mm Hg over MAP. Biphasic waveforms returned once IAP fell to an average of 5 mm Hg over MAP. CONCLUSIONS: Increased IAP resulted in tamponade of epiphyseal perfusion in the young, but not in the older hips. An intact physis may preclude intraosseous metaphyseal vessels from penetrating the epiphysis, leaving it vulnerable to retinacular artery tamponade. CLINICAL RELEVANCE: The IAP and EPP relationship has direct clinical practice implications. Hip capsulotomy and decompression in young patients with intra-articular proximal femoral fractures and increased intracapsular pressure may decrease avascular necrosis risk.

Osteonecrosis After Contralateral in Situ Prophylactic Pinning for a Slipped Capital Femoral Epiphysis: A Case Report.

CASE: We report the case of an 11-year-old girl who developed osteonecrosis of the femoral head in the radiographically normal, asymptomatic left hip that had been fixed prophylactically in the context of a slipped capital femoral epiphysis (SCFE) that had been detected on the contralateral hip. The etiology of the osteonecrosis remains unknown. CONCLUSION: This case report demonstrates that prophylactic fixation of a radiographically normal, asymptomatic hip in the context of an SCFE on the contralateral side has the potential for substantial complications. Therefore, the risk of osteonecrosis in the prophylactically pinned hip should be carefully considered because this complication may have devastating functional consequences.

Slipped capital femoral epiphysis: is it worth the risk and cost not to offer prophylactic fixation of the contralateral hip?

Controversy remains whether the contralateral hip should be fixed in patients presenting with unilateral slipped capital femoral epiphysis (SCFE). This retrospective study compares the outcomes and cost of those patients who had prophylactic fixation with those who did not. Between January 2000 and December 2010 a total of 50 patients underwent unilateral fixation and 36 had prophylactic fixation of the contralateral hip. There were 54 males and 32 females with a mean age of 12.3 years (9 to 16). The rate of a subsequent slip without prophylactic fixation was 46%. The risk of complications was greater, the generic health measures (Short Form-12 physical (p < 0.001) and mental (p = 0.004) summary scores) were worse. Radiographic cam lesions in patients presenting with unilateral SCFE were only seen in patients who did not have prophylactic fixation. Furthermore, prophylactic fixation of the contralateral hip was found to be a cost-effective procedure, with a cost per quality adjusted life year gained of £1431 at the time of last follow-up. Prophylactic fixation of the contralateral hip is a cost-effective operation that limits the morbidity from the complications of a further slip, and the diminished functional outcome associated with unilateral fixation.

Slipped capital femoral epiphysis: prevalence, pathogenesis, and natural history.

BACKGROUND: Obesity is a risk factor for developing slipped capital femoral epiphysis (SCFE). The long-term outcome after SCFE treatment depends on the severity of residual hip deformity and the occurrence of complications, mainly avascular necrosis (AVN). Femoroacetabular impingement (FAI) is associated with SCFE-related deformity and dysfunction in both short and long term. QUESTIONS/PURPOSES: We examined obesity prevention, early diagnosis, reducing AVN and hip deformity as strategies to reduce SCFE prevalence, and the long-term outcomes after treatment. METHODS: A search of the literature using the PubMed database for the key concepts SCFE and treatment, natural history, obesity, and prevalence identified 218, 15, 26, and 49 abstracts, respectively. WHERE ARE WE NOW?: A correlation between rising childhood obesity and increasing incidence of SCFE has been recently reported. Residual abnormal morphology of the proximal femur is currently believed to be the mechanical cause of FAI and early articular cartilage damage in SCFE. WHERE DO WE NEED TO GO?: Reducing the increasing prevalence rate of SCFE is important. Treatment of SCFE should aim to reduce AVN rates and residual deformities that lead to FAI to improve the long-term functional and clinical outcomes. HOW DO WE GET THERE?: Implementing public health policies to reduce childhood obesity should allow for SCFE prevalence to drop. Clinical trials will evaluate whether restoring the femoral head-neck offset to avoid FAI along with SCFE fixation allows for cartilage damage prevention and lower rates of osteoarthritis. The recently described surgical hip dislocation approach is a promising technique that allows anatomic reduction with potential lower AVN rates in the treatment of SCFE.

Management of the contralateral hip in patients with unilateral slipped upper femoral epiphysis: to fix or not to fix--consequences of two strategies.

In the majority of patients with slipped upper femoral epiphysis only one hip is involved at primary diagnosis. However, the contralateral hip often becomes involved over time. There are no reliable factors predicting a contralateral slip. Whether or not the contralateral hip should undergo prophylactic fixation is a matter of controversy. We present a number of essential points that have to be considered both when choosing to fix the contralateral hip prophylactically as well as when refraining from surgery and instead following the patients with repeat radiographs.

The asymptomatic contralateral hip in unilateral slipped capital femoral epiphysis: morbidity of prophylactic fixation.

Prophylactic contralateral fixation in unilateral slipped capital femoral epiphysis (SCFE) remains a controversial issue. In this study, 66 patients treated for unilateral SCFE (July 1997-April 2009) were screened for complications with need for surgical reintervention in the asymptomatic contralateral hip. Except for one patient, prophylactic fixation was performed in all cases. Major complications such as avascular necrosis were not seen; minor complications such as wound revision occurred in 4.6% (three of 65). In 16.9% (11/65) secondary loss of fixation with need for second fixation occurred. As the need for second fixation arose mostly bilaterally (10.7%, 7/65), only four patients (6.2%) required an additional surgical procedure for second fixation. Children who needed second fixation were significantly younger (11.8 years) than those who did not (13.1 years, P=0.013). In conclusion, this retrospective analysis shows that prophylactic contralateral fixation in SCFE is a safe procedure with no major complications and an acceptable rate of minor complications. When Kirschner wires are used for prophylactic pinning, there is a possibility of secondary loss of fixation due to length growth at the level of the physis. To avoid the need for secondary fixation, screw epiphysiodesis might be considered.