Increased intracapsular pressures after unstable slipped capital femoral epiphysis

Intraoperative Epiphyseal Perfusion Monitoring Does Not Reliably Predict Osteonecrosis Following Treatment of Unstable SCFE

BACKGROUND

Avascular necrosis (AVN) remains the most dreaded complication of unstable slipped capital femoral epiphysis (SCFE) treatment. Newer closed reduction techniques (with perfusion monitoring) have emerged as a technically straightforward means to address residual SCFE deformity while still minimizing the risk of osteonecrosis. However, limited data exists regarding the reliability of intraoperative epiphyseal perfusion monitoring to predict the development of AVN. The purpose of this study was to evaluate its reliability.

METHODS

We retrospectively reviewed all patients with unstable SCFE who underwent closed or open reduction with epiphyseal perfusion monitoring using an intracranial pressure (ICP) probe from 2015 to 2023 at a single institution with a minimum 6-month radiographic follow-up. Demographic, clinical, and radiographic data were recorded, including duration of symptoms, type of reduction, capsulotomy performed, presence of a waveform on ICP monitoring after epiphyseal fixation, and development of AVN on follow-up radiographs.

RESULTS

Our cohort included 33 hips (32 patients), of which 60.6% (n=20) were male. The average age was 12.5±1.8 years, with a median follow-up of 15.8 months. Eleven hips were treated with open reduction using the modified Dunn technique (10 hips) or anterior approach (1 hip), and 22 hips were treated with inadvertent (5 hips) or purposeful closed reduction using the Leadbetter technique (17 hips). Overall, 8 of the 33 hips in our series (24.2%) developed AVN, 6 of which (20%) had a pulsatile waveform on intraoperative epiphyseal perfusion monitoring. The overall rate of AVN after closed reductions was 31.8% (7 of 22 hips); the incidence of AVN after closed reduction with a detectable waveform was 30% (6 of 20 hips). There was no significant association between time to surgery ( P =0.416) or type of reduction ( P =0.218) and the incidence of AVN.

CONCLUSIONS

In this series, intraoperative epiphyseal perfusion monitoring did not reliably predict the development of osteonecrosis. To our knowledge, this is the first study to report AVN after demonstrable intraoperative epiphyseal perfusion following closed reduction of unstable slips.

LEVEL OF EVIDENCE

Level IV: case series-therapeutic study.

Avascular Necrosis and Time to Surgery for Unstable Slipped Capital Femoral Epiphysis: A Systematic Review and Meta-analysis

BACKGROUND

Avascular necrosis (AVN) is a well-known complication of unstable slipped capital femoral epiphysis (SCFE) and its cause is multifactorial. Higher AVN rates have been reported with surgery undertaken between 24 hours to 7 days from the onset of symptoms. The current evidence regarding time to surgery and AVN rate remains unclear. The aim of our study was to investigate the rate of AVN and time to surgery in unstable SCFE.

METHODS

A literature search of several databases was conducted. Eligibility criteria included all studies that reported AVN rates and time to surgery in unstable SCFE patients. We performed a meta-analysis using a random-effects model to pool the rate of AVN in unstable SCFE using different time to surgery subgroups (≤24 h, 24 h - 7 d and >7 d). Descriptive, quantitative and qualitative data were extracted.

RESULTS

Twelve studies matched our eligibility criteria. In total, there were 434 unstable SCFE of which 244 underwent closed reduction (CR). The pooled AVN rates were 24% [95% CI: 16%-35%] and 29% [95% CI: 16%-45%] for the total and CR groups, respectively. The highest AVN rates were with surgery between 24 hours to 7 days, 42% and 54% for the total and CR groups, respectively. The lowest rates of AVN were with time to surgery ≤24 hours (22% and 21% respectively) and >7 days (18% and 29% respectively). These differences were not statistically significant. There was significant subgroup heterogeneity which was highest in the 24 hours - 7 days subgroup and lowest in the >7 days subgroup.

CONCLUSIONS

The cumulative evidence was not conclusive for an association between AVN rate and time to surgery. The overall AVN rates were lower in unstable SCFE patients who had surgery ≤24 hours and >7 days. However, treatment techniques were very variable and there was significant heterogeneity in the included studies. Multi-centre prospective studies are required with well-defined time to surgery outcomes.

LEVEL OF EVIDENCE

Level III/IV.

Slipped capital femoral epiphysis: Diagnostic pitfalls and therapeutic options

One of the most prevalent hip pathologies that develops during adolescence is Slipped Capital Femoral Epiphysis (SCFE), and over the past few decades, its incidence has been rising. To ensure an early diagnosis and prompt intervention, orthopedic surgeons should be aware of this entity. Review of recent developments in clinical examination and imaging diagnostic procedures. The presentation includes commonly used imaging methods, slippage measurement techniques, and classification schemes that are pertinent to treatment. An overview of SCFE surgery based on pertinent study findings and knowledge gained from ongoing clinical practice. The gold standard treatment for stable SCFE cases— those in which the continuity of the metaphysis and epiphysis is preserved—is pinning in situ using a single cannulated screw without reduction. However, there are disagreements over the best course of action for stable moderate/severe SCFE. On the best surgical strategy for unstable epiphysiolysis, no universal agreement has been reached. Finding the surgical procedure that will improve the long-term outcomes of a slipped capital femoral epiphysis is the question at hand.

Necrose avascular pós-cirurgia de Dunn modificada no tratamento do escorregamento da epífise proximal do fêmur*

Objective  The present study analyzed the incidence of epiphyseal avascular necrosis in patients with slipped capital femoral epiphysis (SCFE) treated using a modified Dunn technique. In addition, this study determined the correlation of other variables with this incidence and described treatment complications.

Methods  This is a retrospective study with 20 patients treated by the same surgical team from 2009 to 2019 and followed up for 2 to 12 years. The analysis included general features, time from presentation to surgical procedure, classification, and intraoperative blood perfusion of the epiphysis, as well as complications and their treatment.

Results  All cases were severe; 65% were acute on chronic, and 55% of the SCFEs were unstable. Our complication rate was 45%, with 5 cases of avascular necrosis, 2 cases of deep infection, 1 case of material failure, and 1 case of joint instability. The statistical analysis revealed that the risk of necrosis was higher when the surgery occurred after a long hospitalization time and there was no intraoperative epiphyseal perfusion. Four necrosis cases happened within the first 5 years, and 1 case in the last 5 years of the study.

Conclusion  Our study showed that necrosis was the most common complication. It also revealed that surgery delay and lack of intraoperative epiphysis perfusion potentially predispose to avascular necrosis. Although with no statistical significance, coxofemoral instability occurred in chronic SCFE, and surgical fixation with threaded wires was less effective than fixation with a cannulated screw.

The modified Dunn procedure should be reserved for severe cases in which other techniques are not feasible and performed by an experienced, trained, and qualified team.

Comparison between anterior cuneiform osteotomy and Dunn procedure in the surgical management of unstable severe slipped femoral epiphysis: A case-control study of 41 patients

BACKGROUND

There is little consensus on the best treatment algorithm for unstable severe slipped capital femoral epiphysis (SCFE). Subcapital osteotomy, which is one of the surgical options, is performed either anteriorly (anterior cuneiform osteotomy, CO) or laterally with trochanteric osteotomy (Dunn procedure, DP). The CO is technically easier and decreases operating time. Moreover, because the DP was the standard in our department before it was replaced by the CO, we had a series of consecutive patients. Therefore, we did a retrospective case-control study in unstable, severe SCFEs treated by CO versus DP, which is to our knowledge the first one aiming to compare: (1) postoperative complications and in particular avascular necrosis, (2) functional outcome, (3) radiologic findings.

HYPOTHESIS

CO is less or just as likely to cause avascular necrosis and has the same clinical and radiologic findings as DP.

METHODS

A total of 41 patients (24 girls, i.e. 58.5%) were included between 2005 and 2018: 23 in the CO group and 18 in the DP group. The median age was 12.9 years (range, 11.5-14.9) and the median slip angle 70̊ (range, 62.5̊-80̊) with a median follow-up of 3 years (range, 2-4). Preoperative, intraoperative, and postoperative clinical and radiologic parameters (Southwick and alpha angles, and femoral head-neck offset) were analyzed, and all complications were documented.

RESULTS

Two (8.7%) cases of avascular necrosis were reported in the CO group and 6 (33.3%) in the DP group (p=.11), with an overall rate of avascular necrosis of 19.5% (8/41). Five out of the 41 patients (12.2%) underwent a total hip arthroplasty: 1/23 (4.3%) in the CO group and 4/18 (22.2%) in the DP group (p=.16). Two (9.5%) patients in the CO group and 7 (38.9%) in the DP group developed postoperative limping before any arthroplasty was performed (p=.055). The alpha angle at follow-up (54±6.1̊ vs. 59.1±7.2̊; p=.027), Oxford hip score at follow-up (17/60 [range, 14-20] vs. 23.5 [range, 19-27]) (p=.021), operating time (132 min [range, 103-166] vs. 199.5 min [range, 142-215]) (p=.011) and intraoperative bleeding (250 mL [range, 100-350] vs. 300 mL [range, 197-450]) (p=.088) were more favorable in the CO group than in the DP group.

CONCLUSIONS

The CO has similar results to DP in the surgical management of unstable severe SCFE.

LEVEL OF EVIDENCE

III; retrospective comparative study.

Controversies in the Management of Unstable Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) involves anterior-superior displacement of the proximal metaphysis relative to the epiphysis of the proximal femur. It is the most common hip disorder affecting the pediatric population. SCFE has a higher incidence in adolescent males in addition to racial and regional predilections. Despite being described over 500 years ago, there remains controversy surrounding the topic. This article examines current concepts in SCFE, with a spotlight on treatment. An evidence-based discussion of treatment controversies regarding reduction method, fixation construct, supplemental procedures and surgical timing is included.

Diagnosis and Management of Unstable Slipped Capital Femoral Epiphysis: A Critical Analysis Review

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An unstable slipped capital femoral epiphysis (SCFE) is characterized by the inability to walk and is associated with a high risk of osteonecrosis.

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An unstable SCFE is less common than a stable SCFE; however, the demographics are similar in both groups of patients with SCFE.

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The diagnosis of an unstable SCFE is characterized by a history of antecedent pain and the inability to walk on examination, and it is confirmed by radiographic assessment.

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Management of an unstable SCFE includes closed reduction, open reduction, and capital realignment, which have all been noted to have lower rates of osteonecrosis than reported in historic reports.

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All management approaches have certain advantages and disadvantages, and comparative studies are needed to guide clinical decision-making.

Intraoperative assessment of femoral head perfusion during surgical hip dislocation for slipped capital femoral epiphysis

Avascular necrosis is the most devastating complication of slipped capital femoral epiphysis, leading to collapse of the femoral head, increased risk of osteoarthritis and the requirement of early total hip arthroplasty. It is believed that intraoperative femoral head perfusion assessment may be an accurate predictor of post-operative avascular necrosis (radiographic collapse). At our institution, femoral head perfusion is assessed intraoperatively during all sub-capital realignment procedures. We hypothesize that our method is accurate in predicting the risk of developing post-operative avascular necrosis. In this retrospective study, we collected data from all patients that had intraoperative blood flow measurements during sub-capital realignment procedures. We correlated this with long-term radiographs looking for radiographic collapse. The intraoperative femoral head perfusion assessments during sub-capital realignment procedures for slipped capital femoral epiphysis at our institution, between January 2015 and March 2020 inclusive were assessed for reliability. In total, 26 of 35 patients had intraoperative femoral head perfusion present. Only 2 (8%) of these patients developed radiographic collapse. In contrast, 7 (78%) of the 9 patients who did not have femoral head perfusion present intraoperatively developed radiographic collapse, indicating that our method may be reliable in predicting a patient’s post-operative risk of developing avascular necrosis.

Epiphyseal Translation as a Predictor of Avascular Necrosis in Unstable Slipped Capital Femoral Epiphysis

BACKGROUND

Physeal instability has been shown to be associated with a higher risk of avascular necrosis (AVN) in patients with slipped capital femoral epiphysis (SCFE). The purpose of this study was to identify additional preoperative factors associated with AVN in patients with unstable SCFE.

METHODS

Basic demographic information, chronicity of symptoms, and estimated duration of nonambulatory status were noted. Preoperative radiographs were used to measure the Southwick slip angle, slip severity by Wilson criteria, and epiphyseal translation. Translation was measured by 3 distinct radiographic parameters in the position demonstrating maximal displacement. Postoperative radiographs at the time of most recent follow-up were assessed for the presence of AVN. Translation measurements were tested for inter-rater reliability. Patients who developed AVN were compared with those that did not by Fisher exact test and Wilcoxon tests. Logistic regression assessed the effect of translation on the odds of developing AVN. Receiver operating characteristic curve was plotted to assess any threshold effect.

RESULTS

Fifty-one patients (55 hips) out of 310 patients (16%) treated for SCFE were considered unstable. Seventeen hips' unstable SCFE (31%) showed radiographic evidence of AVN. Slip severity by Wilson grade (P=0.009) and epiphyseal translation by all measurements (P< 0.05) were statistically significantly greater among patients who developed AVN. Superior translation had the best inter-rater reliability (intraclass correlation coefficient=0.84). Average superior translation in hips that developed AVN was 17.2 mm compared with 12.9 mm in those that did not (P<0.02). Although the receiver operating characteristic curve did not demonstrate a threshold effect for AVN, it did effectively rule out AVN in cases with <1 cm of superior translation. Age, sex, laterality, chronicity of prodromal symptoms or inability to bear weight, Southwick slip angle, and method of treatment did not vary with the occurrence of AVN.

CONCLUSIONS

Epiphyseal translation, either by Wilson Grade or measured directly, is associated with AVN in patients with an unstable SCFE.

LEVEL OF EVIDENCE

Level II-development of diagnostic criteria.

Bilateral Femoral Neck Fractures in the Setting of Bilateral Slipped Capital Femoral Epiphysis: A Case Report

CASE

A 16-year-old adolescent boy with autism and vitamin D deficiency sustained a seizure and had bilateral femoral neck fractures and slipped capital femoral epiphysis (SCFEs). He underwent closed reduction and screw stabilization of femoral neck fractures with incorporation of in situ screw fixation of SCFEs. Intraosseous epiphyseal perfusion monitoring was used to confirm the perfusion of the femoral head. Two years postoperatively, he had healed fractures and no evidence for avascular necrosis.

CONCLUSION

A femoral neck fracture in the setting of a SCFE can be treated with closed reduction of the femoral neck fracture and screw fixation. Intraepiphyseal perfusion monitoring can be used to qualitatively assess femoral head perfusion.

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.

Factors Affecting Outcomes of Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) is a frequent cause of nontraumatic painful hip of the adolescence. It is the result of the separation of the proximal femoral growth cartilage at the level of the hypertrophic cell zone. The femoral neck metaphysis rotates externally and migrates proximally relative to the femoral head epiphysis, which is stably seated in the acetabulum; early diagnosis and in situ stabilization grants the best long term results. Numerous factors affect treatment outcomes. Not all implants have the same effect on the slipped physis. Application of the traditionally used implants, such as non-threaded pins and cannulated screws, is questioned. Modern implants are available, which stabilize the slip without accelerating physis fusion. This allows femoral head and neck growth and remodeling to limit the post-slip sequellae on hip anatomy and function. Femoroacetabular impingement (FAI) complicates almost all slips. It causes progressive labral and articular cartilage damage and leads to early hip osteoarthritis and total hip replacement, approximately ten years earlier compared to the general population. Avascular necrosis of the femoral head is a dramatic complication, seen almost exclusively in unstable slips. It develops within months after the slip and leads to immediate articular joint degeneration and the need for total hip replacement. Another serious complication of SCFE is chondrolysis, which is a rapid progressive articular cartilage degeneration leading to a narrow joint space and restriction of hip motion. Implant-related complications, such as migration and loosening, may lead to the progression of the slip. Though bilateral disease is quite frequent, there is no consensus about the need for preventive surgery on the healthy contralateral hip. Diagnosis of SCFE is frequently missed or delayed, leading to slips of higher severity. Silent slippage of the capital femoral epiphysis is highly suspected as an underlying cause of cam-type FAI and early-onset hip osteoarthritis. There is controversy, whether asymptomatic implants should be removed. Novel surgical techniques, such as the modified Dunn procedure and hip arthroscopy, seem to be effective modalities for the prevention of FAI in SCFE.

Capsulotomy in Unstable Slipped Capital Femoral Epiphysis and the Odds of AVN: A Meta-analysis of Retrospective Studies

BACKGROUND

Unstable slipped capital femoral epiphysis (SCFE) may lead to avascular necrosis (AVN) in up to 60% of patients. The aim of this study was to assess the best clinical evidence to determine the effect of capsular decompression (CD) on odds of AVN in unstable SCFE.

METHODS

Medline, Embase, and Cochrane databases were systematically searched for comparative studies investigating AVN rates in unstable SCFE treated with or without CD (aspiration, percutaneous, or open). Quality was evaluated by the Newcastle Ottawa Scale. A comparative analysis with pooled effect estimates using random-effects modeling was calculated. Secondary analysis pooled AVN rates from both comparative studies and case series.

RESULTS

Comparative analysis included 17 retrospective studies with 453 hips (201 with CD, 252 without CD). Thirty-four of 201 (17%) hips with CD developed AVN, while 67 of 252 (27%) hips without CD developed AVN. The odds of AVN for patients treated with or without CD [odds ratio=0.80, 95% confidence interval (CI): 0.48-1.35] was not statistically different. Subanalysis on patients treated with in situ pinning or positional reduction and pinning showed no difference in AVN rates with or without CD (odds ratio=0.97, 95% CI: 0.44-2.10). In the secondary analysis of 17 comparative studies and 23 case series, the average rate of AVN was 17%, 0.17 (95% CI: 0.13-0.23) for patients treated with CD (60/447 hips) and 28%, 0.28 (95% CI: 0.22-0.35) for patients treated without CD (129/464 hips).

CONCLUSIONS

There was no statistically significant decrease in odds of AVN with CD. However, studies were limited by their retrospective nature and inadequate documentation of CD techniques; the majority lacked femoral head blood flow monitoring to demonstrate adequate decompression. Future prospective studies with carefully documented complete decompression may help to elucidate the effect of CD on AVN risk. Although there was no statistically different odds of AVN with or without CD, even this large meta-analysis was underpowered, and one cannot conclude that there was truly no difference in odds of AVN without an appropriately powered study. Therefore, we recommend routine CD for all unstable SCFEs pending additional research, as CD adds little to the surgical procedure and may minimize the risk of a devastating insult to the femoral head.

Natural History of Slipped Capital Femoral Epiphysis

BACKGROUND

Slipped capital femoral epiphysis (SCFE) occurs at a rate of 1 in 10,000 to 20,000 children.

METHODS

A PubMed search was undertaken to evaluate recent SCFE literature. A convenience sample of articles were selected and summarized.

RESULTS

Most slips appear well tolerated long-term with ∼5% resulting in total hip arthroplasty (THA) at 20-year follow-up. Classic data reveals poor outcomes following closed reduction for treatment of SCFE. Improvements in intraoperative fluoroscopy and avoidance of pin penetration have reduced the rates of chondrolysis. Unfortunately, avascular necrosis remains a known risk in patients, occurring in 15% to 50% of patients following acute, unstable slips. This is the most common cause of THA in patients with SCFE. Rate of THA due to degenerative arthritis secondary to SCFE is more difficult to determine and occurs at a later age. Although realignment procedures to address anatomic abnormalities from SCFE have increased in popularity, it is unclear if this prevents degenerative arthritis and subsequently reduces the rate of THA. SCFE patients face an increased risk of disability and death due to their underlying medical comorbidities. Interventions for weight loss, blood pressure management, and lifestyle adjustments should be considered at the time of SCFE diagnosis.

CONCLUSIONS

SCFE remains a challenging and common condition for pediatric orthopedists. Although innovative techniques have been proposed, long-term outcome data still supports in situ pinning for stable slips, and in situ pinning with capsular decompression for unstable slips to minimize the risk of avascular necrosis.

Outcomes after slipped capital femoral epiphysis: a population-based study with three-year follow-up

PURPOSE

To evaluate outcomes three years after treatment for slipped capital femoral epiphysis (SCFE): development of avascular necrosis (AVN), subsequent surgery, hip function and the contralateral hip.

METHODS

This prospective cohort study included a total national population of 379 children treated for SCFE between 2007 and 2013. A total of 449 hips treated for SCFE and 151 hips treated with a prophylactic fixation were identified. The Barnhöft questionnaire, a valid patient-reported outcome measure (PROM), was used.

RESULTS

In all, 90 hips had a severe slip, 61 of these were clinically unstable. AVN developed in 25 of the 449 hips. Six of 15 hips treated with capital realignment developed AVN. A peri-implant femur fracture occurred in three slipped hips and in two prophylactically pinned hips. In three of these five hips technical difficulties during surgery was identified. In 43 of 201 hips scheduled for regular follow-up a subsequent SCFE developed in the contralateral hip. Implant extraction after physeal closure was performed in 156 of 449 hips treated for SCFE and in 51 of 151 prophylactically fixed hips. Children with impaired hip function could be identified using the Barnhöft questionnaire.

CONCLUSION

Fixation in situ is justified to remain as the primary treatment of choice in SCFE. Overweight is more common in children with SCFE than in the average population. Prophylactic fixation is a safe procedure when performed using a correct technique. The number of patients who developed AVN after capital realignment is of concern. We recommend rigorous follow-up of both hips, including PROM evaluation, until physeal closure.

LEVEL OF EVIDENCE

II - prospective cohort study.

Restoration of Blood Flow to the Proximal Femoral Epiphysis in Unstable Slipped Capital Femoral Epiphysis by Modified Dunn Procedure: A Preliminary Angiographic and Intracranial Pressure Monitoring Study

BACKGROUND

The major complication of unstable slipped capital femoral epiphysis (SCFE) is avascular necrosis (AVN) of the femoral head. The purpose of this study was to document by angiography the preoperative and postoperative perfusion to the proximal femoral epiphysis following an unstable SCFE. A specific aim was to determine whether blood flow could be restored. A secondary aim was to determine the efficacy of an intracranial pressure (ICP) monitor to assess blood flow within the femoral head intraoperatively.

METHODS

Nine patients with an unstable SCFE underwent superselective angiogram of the medial circumflex femoral artery preoperatively, followed by operative fixation with an open reduction using a modified Dunn approach. Femoral head blood flow was evaluated with an ICP monitor. Angiography was repeated postoperatively. Patients were followed radiographically to assess for AVN.

RESULTS

Follow-up averaged 22 months. Six patients did not have arterial flow to the femoral head on the preoperative angiogram. Flow was restored postoperatively on angiogram in 4 of the 6 patients. Two patients developed AVN. One had no flow to the femoral head preoperatively or postoperatively on angiogram and complete tearing of the periosteum was noted. In 1 patient, there was no ICP waveform after the initial reduction. After removing more callous and repeating reduction, the waveform returned. Of the 2 patients with AVN, 1 had an ICP waveform after reduction.

CONCLUSIONS

This study documents that some patients with unstable SCFE present with reduced femoral head blood supply due to SCFE. It also demonstrates blood flow restoration in 4 patients by angiogram and 5 by ICP monitor after surgical treatment. No patient immediately lost blood flow due to surgery. ICP monitor is a safe intraoperative tool for real-time assessment of femoral head blood flow during open reduction of unstable SCFE. Presence of flow by ICP is not a guarantee that AVN will not develop, but absence of flow was predictive of AVN.

LEVEL OF EVIDENCE

Therapeutic level I-prognostic. See Instructions for Authors for a complete description of levels of evidence.

Treatment of Unstable Slipped Capital Epiphysis Via the Modified Dunn Procedure

BACKGROUND

The modified Dunn procedure has been shown to be safe and effective in treating unstable slipped capital femoral epiphysis (SCFE). We present a consecutive series of unstable SCFE managed by a single surgeon with a focus on timing of surgical intervention, postoperative complications, and radiographic results.

METHODS

Thirty-one consecutive unstable SCFEs were treated. Demographics, presentation time to time of operation, surgical times, and complications were recorded. Bilateral hip radiographs at latest follow-up were utilized to record slip angle, α angle, greater trochanteric height, and femoral neck length.

RESULTS

Thirty-one consecutive hips in 30 patients were reviewed: 15 males (50%) and 15 females (50%), average age 12.37 years (range, 8.75 to 14.8 y), 20 left hips (65%) and 11 right hips (35%). Mean follow-up was 27.9 months (range, 1 to 82 mo). Time from presentation to intervention averaged 13.9 hours (range, 2.17 to 23.4 h). Two patients (6%) developed avascular necrosis at average 19 weeks postoperative. Three patients (10%) developed mild heterotopic ossification requiring no treatment. Two patients (6%) required removal of symptomatic hardware. One patient had hardware failure and in no patients was nonunion, delayed union, or postoperative hip subluxation/dislocation seen. Three patients (10%) presented with bilateral, stable SCFE requiring contralateral in situ pinning. Five patients (16%) had sequential SCFE requiring treatment with 1 patient having an acute, unstable SCFE 10 months after the previous realignment. Mean postoperative slip angle measured 2.5 degrees (range, +19 to -9.4 degrees) (SD, 7.2), α angle 47.43 degrees (range, 34 to 64 degrees) (SD, 7.49), greater trochanteric height averaged 3.5 mm below the center of femoral head (-17.5 to +25 mm), and mean femoral neck length difference measured -7.75 mm (range, -1.8 to -18.6 mm).

CONCLUSIONS

A single surgeon series of unstable SCFEs treated by a modified Dunn procedure showed a 6% incidence of avascular necrosis and low complication rates at latest follow-up. Radiographs showed restoration of the slip angle, α angle, femoral neck length, and greater trochanteric height. This series reveals the safety and effectiveness of the modified Dunn procedure for unstable SCFE.

LEVEL OF EVIDENCE

Level III-retrospective review.

Slipped capital femoral epiphysis: a population-based study

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in children 9-15 years old. This is a population-based study in Sweden presenting the epidemiology for SCFE.

METHODS

In a prospective cohort study, we analysed pre- and postoperative radiographs, medical records for all children treated for SCFE in Sweden 2007-2013, demographic data, severity of slip and surgical procedures performed.

RESULTS

We identified 379 Swedish children with primary SCFE 2007-2013; 162 girls, median age 11.7 (7.2-15.4) years, and 217 boys, median age 13 (3.8-17.7) years. The average annual incidence was 4.4/10000 for girls and 5.7/10000 for boys 9-15 years old. Obesity or overweight was found in 56% of the girls and in 76% of the boys. As an initial symptom, 66% of the children had hip/groin pain and 12% knee pain. At first presentation, 7% of the children had bilateral SCFE. Prophylactic fixation was performed in 43%. Of the remaining children, 21% later developed a contralateral slip. Fixation with implants permitting further growth was used in >90% of the children. Femoral neck osteotomy was performed for 11 hips.

CONCLUSIONS

The annual average incidence 2007-2013 in Sweden showed a mild increase for girls. The male-to-female ratio was lower than previous regional data from Sweden. Overweight or obesity is one major characteristic for boys with SCFE but to a less extent for girls. Knee pain as initial symptom cause a delay in diagnosis. Most hospitals in Sweden treat <2 children annually.

Slipped capital femoral epiphysis: a spectrum of surgical care and changes over time

PURPOSE

To survey the spectrum of surgical care in children with slipped capital femoral epiphysis (SCFE). This information is valuable in counselling the patient about the future treatment course.

METHODS

Data for this study were obtained from the Pediatric Hospital Information System (PHIS) between 2004 and 2015. For all patients with an ICD9 diagnosis of 732.2, gender, ethnicity, hospital, medical record number, date of birth/admission/discharge, type of admission, length of stay, disposition and treatment(s) rendered were collected.

RESULTS

A total of 13 168 procedures were performed in 11 058 unique SCFE patients, or 1.2 procedures per patient. Primary procedures were those performed for the initial treatment of the SCFE and secondary procedures as reconstructive and salvage. The majority (11 693, 88.8%) were primary. There was significant variation in the ratio of primary and secondary procedures by institution. There was a decline in in situ fixation as the initial SCFE treatment with an increase in open reduction and internal fixation over the 12-year span. Similarly, there was a significant increase in the number of secondary procedures over time as well as complications and implant removal. There was no change over time in the diagnosis of avascular necrosis.

CONCLUSIONS

The average number of surgical procedures in patients was in the range of 1 to 6 and varied widely by hospital. Each physician should know his/her own hospital's data for the percentage of subsequent procedures so as to counsel the patient and family properly. The increasing number of complications over time may reflect the increasing number of more complex procedures.

Intraoperative Monitoring of Epiphyseal Perfusion in Slipped Capital Femoral Epiphysis: Surgical Technique

Introduction

Intraoperative monitoring of epiphyseal perfusion in slipped capital femoral epiphysis (SCFE) is a procedurally simple and readily accessible percutaneous technique to accurately guide decision-making and help to prevent osteonecrosis.

Indications & Contraindications

Step 1 Patient Preparation and Positioning

Following anesthesia induction, position the patient and assess the physeal stability fluoroscopically to determine the need for a reduction.

Step 2 Guidewire Placement

Place a 3.2-mm threaded guidewire from the anterolateral aspect of the femur to provide initial stability of the slipped epiphysis.

Step 3 Initial Screw Insertion

Insert a cannulated 7.0-mm stainless steel screw over the guidewire to a point just past the physis.

Step 4 Preparation and Insertion of the ICP Probe

Once the screw has been inserted to obtain provisional stability of the physis, remove the guidewire and insert a sterile ICP probe down the screw shaft to assess the epiphyseal perfusion.

Step 5 Hip Decompression

If a perfusion pressure and waveform cannot be obtained, perform decompression of the hip capsule by either aspiration or capsulotomy.

Step 6 Epiphyseal Perfusion Reassessment

Following the capsulotomy, reinsert the ICP probe and reassess the epiphyseal perfusion.

Step 7 Final Screw Advancement

Once epiphyseal blood flow can be confirmed, reintroduce the guidewire to its previous depth and advance the screw to the final measured depth.

Results

Utilizing this technique over a 5-year period, >35 patients were treated with the described technique, and 23 of them, including 29 hips, were included in our referenced prospective study³.

Pitfalls & Challenges

Is the timing of surgery associated with avascular necrosis after unstable slipped capital femoral epiphysis? A multicenter study

BACKGROUND

An unstable slipped capital femoral epiphysis (SCFE) is associated with a high rate of avascular necrosis (AVN). The etiology of AVN seems to be multifactorial, although it is not thoroughly known. The aims of our study were to determine the rate of AVN after an unstable SCFE and to investigate the risk factors for AVN, specifically evaluating the notion of an "unsafe window", during which medical interventions would increase the risk for AVN.

METHODS

This retrospective multicenter study included 60 patients with an unstable SCFE diagnosed between 1985 and 2014. Timing of surgery was evaluated for three time periods, from acute onset of symptoms to surgery: period I, <24 h; period II, between 24 h and 7 days; and period III, >7 days. Multivariate logistic regression analysis was used to identify risk factors for AVN.

RESULTS

Closed reduction and pinning was performed in 43 patients and in situ pinning in 17. Among these cases, 16 patients (27%) developed AVN. The rate of AVN was significantly higher in patients treated by closed reduction and pinning (15/43, 35%) than in those treated by in situ pinning (1/17, 5.9%) (p = 0.022). In patients treated by closed reduction and pinning, the incidence of AVN was 2/11 (18%) in period I, 10/13 (77%) in period II and 3/15 (20%) in period III, showing the significantly higher rate in period II (p = 0.002). The surgery provided in period II was identified as an independent risk factor for the development of AVN.

CONCLUSIONS

Our rate of AVN was 27% using two classical treatment methods. Time-to-surgery, between 24 h and 7 days, was independently associated with AVN, supporting the possible existence of an "unsafe window" in patients with unstable SCFE treated by closed reduction and pinning.

Is Assessment of Femoral Head Perfusion During Modified Dunn for Unstable Slipped Capital Femoral Epiphysis an Accurate Indicator of Osteonecrosis?

BACKGROUND

The modified Dunn procedure, which is an open subcapital realignment through a surgical dislocation approach, has gained popularity for the treatment of unstable slipped capital femoral epiphysis (SCFE). Intraoperative monitoring of the femoral head perfusion has been recommended as a method of predicting osteonecrosis; however, the accuracy of this assessment has not been well documented.

QUESTIONS/PURPOSES

We asked (1) whether intraoperative assessment of femoral head perfusion would help identify hips at risk of developing osteonecrosis; (2) whether one of the four methods of assessment of femoral head perfusion is more accurate (highest area under the curve) at identifying hips at risk of osteonecrosis; and (3) whether specific clinical features would be associated with osteonecrosis occurrence after a modified Dunn procedure for unstable SCFE.

METHODS

Between 2007 and 2014, we performed 29 modified Dunn procedures for unstable SCFE (16 boys, 11 girls; median age, 13 years; range, 8-17 years); two were lost to followup before 1 year. During this period, six patients with unstable SCFE were treated by other procedures. All patients undergoing modified Dunn underwent assessment of epiphyseal perfusion by the presence of active bleeding and/or by intracranial pressure (ICP) monitoring. In the initial five patients perfusion was recorded once, either before dissection of the retinacular flap or after fixation by one of the two methods. In the remaining 22 patients (81%), perfusion was systematically assessed before dissection of the retinacular flap and after fixation by both methods. Minimum followup was 1 year (median, 2.5 years; range, 1-8 years) because osteonecrosis typically develops within the first year after surgery. Patients were assessed for osteonecrosis by the presence of femoral head collapse at radiographs obtained every 3 months during the first year after surgery. Seven (26%) of the 27 patients developed osteonecrosis. Measures of diagnostic accuracy including sensitivity, specificity, and the area under the receiver operating curve (AUC) were estimated. Multiple variable logistic regression analyses were used to test whether the test options were better than random chance (AUC > 0.50) at differentiating between patients who did versus did not develop osteonecrosis. Nonparametric methods were used to test for a difference in AUC across the four methods. A secondary analysis was performed to identify risk factors associated with osteonecrosis.

RESULTS

After adjusting for body mass index, which was found to be a confounding variable, assessment of femoral head perfusion with ICP monitoring before retinaculum dissection (adjusted AUC: 0.79; 95% confidence interval [CI], 0.58-0.99; p = 0.006), femoral head perfusion with ICP monitoring after definitive fixation (adjusted AUC: 0.82; 95% CI, 0.65-1.0; p < 0.001), bleeding before retinaculum dissection (adjusted AUC: 0.77; 95% CI, 0.58-0.96; p = 0.006), and bleeding after definitive fixation (adjusted AUC: 0.81; 95% CI, 0.63-0.99; p = 0.001) were found to be helpful at identifying osteonecrosis. We were not able to identify a specific test that had performed best because there was no difference (p = 0.8226) in AUC across the four methods. With the numbers available, we were unable to identify clinical factors predictive of osteonecrosis in our cohort.

CONCLUSIONS

Assessments of femoral head blood perfusion by ICP monitoring or by the presence of active bleeding in combination with the patient's body mass index are effective at differentiating between patients who do versus do not develop osteonecrosis after a modified Dunn procedure for unstable SCFE. Additional research is needed to determine whether information gained from assessment of femoral head perfusion during surgery should be used to guide targeted treatment recommendations that may reduce the development of femoral head deformity secondary to osteonecrosis.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Intraoperative Monitoring of Epiphyseal Perfusion in Slipped Capital Femoral Epiphysis

BACKGROUND

The purposes of this study were to validate an innovative, percutaneous method of monitoring femoral head (epiphyseal) perfusion intraoperatively in patients with slipped capital femoral epiphysis (SCFE) and to investigate an association between intraoperative perfusion and the subsequent development of osteonecrosis.

METHODS

A percutaneous screw fixation technique for SCFE was utilized. A fully threaded, cannulated, stainless-steel 7.0-mm screw was inserted into the epiphysis. The guidewire was removed, and a sterile intracranial pressure (ICP) probe was placed through the screw such that the tip was in the epiphyseal bone past the end of the screw. Intraoperative epiphyseal pressure and waveform were recorded. A prospective analysis of patients undergoing percutaneous screw fixation for unstable or stable SCFE or for prophylactic treatment with the use of this technique to evaluate femoral head perfusion was performed.

RESULTS

This technique was used in 23 patients (29 hips, including 15 hips with unstable SCFE, 11 with stable SCFE, and 3 treated prophylactically). Three hips (2 with unstable SCFE and 1 treated prophylactically) in 2 patients were eliminated from the analysis because of technical problems with the ICP monitor. All hips with stable SCFE and the prophylactically treated hips had measurable pulsatile flow that was synchronous with the patient's heart rate at the initial time of probe insertion. Seven patients (7 hips) with unstable SCFE had measurable, pulsatile flow with initial insertion of the probe, and 6 patients (6 hips) with unstable SCFE had no measurable flow. We were able to demonstrate perfusion following a percutaneous capsular decompression in the patients with no initial flow. All patients left the operating room with measurable femoral head blood flow. At a mean follow-up of 1.6 years for hips with stable SCFE and 2.0 years for those with unstable SCFE, no hip subsequently developed radiographic evidence of osteonecrosis of the femoral head. No complications from the use of the ICP monitor occurred.

CONCLUSIONS

Femoral head perfusion in patients with SCFE can be measured intraoperatively using this technique. Demonstrating femoral head perfusion before leaving the operating room was associated with the absence of osteonecrosis postoperatively.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Complications Related to the Treatment of Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) is a condition of the immature hip in which mechanical overload of the proximal femoral physis results in anterior and superior displacement of the femoral metaphysis relative to the epiphysis. The treatment of SCFE is surgical, as the natural history of nonsurgical treatment is slip progression and early arthritis. Despite advances in treatment, much controversy exists regarding the best treatment, and complication rates remain high. Complications include osteonecrosis, chondrolysis, SCFE-induced impingement, and related articular degeneration, fixation failure and deformity progression, growth disturbance of the proximal femur, and development of bilateral disease.

Current concepts in management of slipped capital femoral epiphysis

Slipped capital femoral epiphysis (SCFE) is a common hip condition that can be disabling. In this review, we provide an orientation on current trends in the clinical management of SCFE including conventional procedures and specialised surgical developments. Different methods of fixation of the epiphysis, risks of complications, and the rationale of addressing deformity, primarily or secondarily, are presented. Although improved understanding of the anatomy, vascularity and implications of residual deformity have changed management strategies, the best modality of treatment that would restore complete vascularity to the femoral head and prevent any residual deformity, impingement and early osteoarthritis remains elusive.

Surgical Hip Dislocation is Safe and Effective Following Acute Traumatic Hip Instability in the Adolescent

BACKGROUND

A traumatic hip dislocation in the pediatric patient is a rare but potentially catastrophic injury. The purpose of this study was to review our early clinical results and radiographic morphology of hips treated with a surgical hip dislocation (SHD) approach for intra-articular hip pathology resulting from traumatic instability in pediatric and adolescent patients.

METHODS

This is a retrospective analysis of a consecutive series of patients presenting with nonconcentric reduction after traumatic hip instability. All patients were treated with a transtrochanteric SHD with concomitant procedures based on intra-articular findings. Radiographic evaluations and Harris Hip Scores were completed at final follow-up.

RESULTS

Eleven male patients, mean age of 12.3 years (range, 9.3 to 16.1 y) and mean body mass index 19.6 kg/m (range, 15.4 to 28.0 kg/m). Intraoperative findings included: labral tear (8), femoral cartilage injury (5), acetabular rim fracture (4), acetabular cartilage delamination (3), loose body (2), and femoral head osteochondral fracture (1). Postoperatively, 1 patient developed a transient peroneal nerve palsy. At a mean 24.5 months (range, 12.0 to 48.1 mo) postoperatively, no hips have radiographic evidence of osteonecrosis. The mean lateral center edge angle was 20 degrees (range, 9 to 38 degrees) with 6 hips of <20 degrees; mean acetabular index 9 degrees (range, -2 to 23 degrees) with 5 hips of >10 degrees; mean α-angle 56 degrees (range, 48 to 62 degrees) with 6 hips of >55 degrees; mean acetabular version 12 degrees (range, 8 to 16 degrees) with 8 hips of <15 degrees. At 1-year follow-up, the mean Harris Hip Score was 95.8 (range, 84.7 to 100).

CONCLUSIONS

Early results suggest that SHD is a safe approach to treat an incomplete reduction following posterior hip instability and is effective for identification and treatment of acute intra-articular pathology. Acetabular dysplasia, relative acetabular retroversion, and/or decreased femoral offset may be risk factors for posterior hip instability in adolescents.

LEVEL OF EVIDENCE

Level IV.

Intracapsular Pressures After Stable Slipped Capital Femoral Epiphysis

PURPOSE

Stable slipped capital femoral epiphysis (SCFE) has been shown to have a lower rate of avascular necrosis than unstable SCFE. A recent study found increased intracapsular hip pressures in the setting of unstable SCFE, thus increasing the risk of osteonecrosis. The purpose of this study was to measure the intracapsular pressure in stable SCFE and compare it to the intracapsular pressure in normal hips and in unstable SCFE.

METHODS

Thirteen hips with stable SCFE and 15 hips with unstable SCFE were identified. Using a side-bored needle, intracapsular hip pressures were measured at the time of surgery. Within these 2 study groups, 11 unaffected (normal) hips were also measured. Diastolic blood pressure and mean arterial pressure at the time of measurement were also recorded.

RESULTS

The average intracapsular hip pressure in the stable SCFE group was 27.0 mm Hg, whereas the average pressure in the unstable SCFE group was 48.2 mm Hg and the average pressure in the normal group was 21.8 mm Hg. There was no significant difference between the normal and stable SCFE groups. There was a statistically significant difference between the stable SCFE and unstable SCFE groups (P<0.001). We found similar trends when comparing the intracapsular hip pressure as a percentage of the mean arterial pressure as well as the difference between diastolic blood pressure and hip pressure.

CONCLUSIONS

As expected, the intracapsular pressure in the setting of stable SCFE approaches that of normal hips. This may explain why the risk of AVN in stable SCFE is significantly lower than that of unstable SCFE. It also supports the idea that capsulotomy is indicated for unstable slips to decrease the elevated hip pressure but not in stable SCFE.

Acute, unstable slipped capital femoral epiphysis with associated congenital coxa vara

Slipped capital femoral epiphysis in patients younger than 10 years is rare and is often associated with some identifiable metabolic or endocrinologic abnormality. We present a case of a 5-year-old girl with an acute, unstable, severe slipped capital femoral epiphysis associated with congenital coxa vara and its surgical management. This association has not been described in previous literature. Surgical treatment is proposed and described.

Severe slipped capital femoral epiphysis: A French multicenter study of 186 cases performed by the SoFOP

INTRODUCTION

The treatment of severe slipped capital femoral epiphysis (SCFE) remains controversial. Despite numerous treatments being available, the outcome of published studies has been variable. Recent studies emphasize that poor reduction of the severe SCFE is responsible for the appearance of joint cartilage lesions and progression towards early osteoarthritis. But surgical reduction of severe SCFE also results in a significant rate of necrosis.

OBJECTIVE

Evaluate the results of various treatment strategies for severe SCFE and identify the optimal course of action.

MATERIAL AND METHODS

This was a French multicenter retrospective study of severe SCFE cases (>45° displacement) evaluated a minimum of 12 months after treatment. The stability of the slipped epiphysis, type of the treatment, delay before treatment, early and short-term complications, Harris and WOMAC functional scores and radiological signs of femoroacetabular impingement (FAI) at the last review were evaluated. A total of 186 cases of severe SCFE in 182 patients were included. One hundred and seven (58.7%) of these were male. The average age was 13 years. The average follow-up was 23 months. The average displacement was 60°. The SCFE was considered stable in 94 cases (50.5%) and unstable in 92 cases (49.5%). The main surgical treatments used by the various centers were in situ fixation (ISF), lateral Dunn, anterior Dunn and reduction using traction or under anesthesia (for unstable forms).

RESULTS

In the stable SCFE cases, there were 6 cases of necrosis (6.4%), all of which occurred after reduction by osteotomy; there were 32 cases of radiological FAI (34%), 30 of which occurred after ISF. The necrosis rate in the unstable SCFE cases was 21.7%: one (11%) after ISF, seven (19%) after anterior Dunn, eight (21%) after preoperative reduction and three (43%) after lateral Dunn.

CONCLUSIONS

The results of this study confirm the diverse nature of SCFE treatments available and the variability of their results. When selecting a treatment for severe SCFE, the goal is to stop the slip and also to prevent osteoarthritis by correcting the hip deformities. The "anterior" Dunn procedure was able to achieve these two goals, while having a lower complication rate than the other reduction techniques.

Closed reduction of slipped capital femoral epiphysis: high-risk factor for avascular necrosis

How should we treat acute/unstable slipped capital femoral epiphysis (SCFE) without the development of avascular necrosis (AVN)? To answer this question, we investigated the risk factors of AVN development after SCFE. Seventy-six hips of 64 patients were classified using two kinds of classification systems, Loder's classification based on instability and the conventional classification based on the duration of symptom, because both classifications are related to AVN development. Of 21 unstable SCFEs, seven hips developed AVN. Of 35 hips defined as acute or acute on chronic, nine hips developed AVN. Two stable SCFEs of Loder's classification developed AVN, one was acute and the other was acute on chronic. No hips of chronic SCFE developed AVN. The factor that had influenced AVN development was only closed reduction, whether purposefully or inadvertently, in an acute or unstable SCFE. On the basis of the findings of this study, one should not embark on any modality of closed reduction for an unstable or acute form of SCFE, as there is a high risk for occurrence of AVN. For the same reason, a traction table should not be used for SCFE fixation, so as to avoid an inadvertent reduction or force that can lead to AVN.

Acute, unstable, slipped capital femoral epiphysis: is there a role for in situ fixation?

BACKGROUND

Slipped capital femoral epiphysis, a common disorder in adolescents, may be increasing in incidence in North America because of the obesity epidemic. In most cases, the slip is mild and can be treated with in situ fixation. Even in more severe cases of a stable slip, in situ fixation remains a widely accepted choice. When the slip is acute and unstable, treatment remains controversial. We reviewed the orthopaedic literature and our personal experience in managing acute, unstable slipped capital femoral epiphysis. The reported range of avascular necrosis (AVN) is high and the literature shows no clear recommendations for the best treatment choice. Treatment choices include: in situ stabilization with possible later corrective osteotomy, formal manipulative closed reduction plus screw fixation, partial reduction through an open approach with the hip joint decompressed (Parsch method), and anatomic reduction by the modified Dunn method. Review of the literature and our experience suggests a high AVN rate in acute unstable slips no matter what treatment method is selected. Most North American reports suggest an AVN rate with in situ screw fixation ranging from 20% to 50%. The method described by Parsch, which includes an urgent, open capsulotomy, joint decompression, and gentle partial reduction, shows a low AVN rate as reported from his institution (<10%). The AVN rate reported for anatomic reduction (modified Dunn procedure) performed through an open surgical hip dislocation was initially quite low, but after being restudied in North American centers appears to be about 25%.

CONCLUSIONS

Safe treatment of an acute unstable slip remains problematic. The literature suggests that these patients should be treated urgently; however, simple in situ stabilization results in a high AVN rate. A likely safer modification is to open the hip anteriorly to decompress the joint and to stabilize after partial reduction as described by Parsch. The modified Dunn method is becoming more widely used, but results in North American centers cite a significant AVN rate.

High-grade SCFE: the role of surgical hip dislocation and reduction

The patient with an unstable slipped capital femoral epiphysis poses a challenging problem to the treating physician to improve the position of the displaced epiphysis to avoid femoroacetabular impingement without developing avascular necrosis (AVN)-a potentially devastating complication. Although the standard operative procedure of in situ pinning following an incidental reduction while positioning the patient on the table, has been the mainstay of treatment in North America, other viable options are available including a surgical dislocation approach to the hip followed by a modified Dunn osteotomy with control of the retinacular vessels, reduction of the epiphysis, and internal fixation with pins or screws. Although technically demanding, this approach offers an opportunity to reduce the epiphysis to avoid femoroacetabular impingement, and limit the possibility for the development of AVN. The early results for this procedure are promising with all studies demonstrating excellent reduction of the epiphysis and an overall lower incidence of AVN when compared with in situ pinning.

Hip decompression of unstable slipped capital femoral epiphysis: a systematic review and meta-analysis

PURPOSE

Slipped capital femoral epiphysis (SCFE) is one of the most common adolescent hip conditions. Unstable SCFE is characterized by sudden and severe hip pain with the inability to weight bear, even with crutches. Osteonecrosis of the femoral head is increased in patients with unstable SCFE. The aim of our study was to systematically review the literature that compares hip decompression to no hip decompression of unstable SCFE.

METHODS

We searched several databases from 1946 to 2014 for any observational or experimental studies that evaluated hip decompression and osteonecrosis of unstable SCFE. We performed a meta-analysis using a random effects model to pool odds ratios (ORs) for the comparison of osteonecrosis between patients undergoing hip decompression and no hip decompression. We also investigated the type of hip decompression performed. Descriptive, quantitative, and qualitative data were extracted.

RESULTS

Of the 17 articles identified, nine studies (eight case series and one retrospective cohort study) were eligible for the meta-analysis, with a total of 302 unstable SCFE. The pooled OR = 0.91 of osteonecrosis between hip decompression and no hip decompression was in favor of hip decompression, but was not statistically significant [95 % confidence interval (CI): 0.47, 1.75; p = 0.54, I (2) = 0 %]. No significant differences in the rates of osteonecrosis were detected in unstable SCFE with open and percutaneous hip decompression alone (OR = 0.97, 95 % CI: 0.36, 2.62; p = 0.69, I (2) = 19.1 %) or hip decompression with bony procedures (OR = 0.99, 95 % CI: 0.35, 2.79; p = 0.69, I (2) = 0 %).

CONCLUSIONS

The cumulative evidence at present does not indicate an association between hip decompression and a lower rate of osteonecrosis of unstable SCFE. However, hip decompression of unstable SCFE remains an option that can potentially decompress the intracapsular hip pressure and optimize the blood flow to the femoral head. Thus, multicenter prospective cohort studies are required and will be able to answer this question with more certainty and a higher level of evidence.

LEVEL OF EVIDENCE

Level III/IV.

The treatment of an unstable slipped capital femoral epiphysis by either intracapsular cuneiform osteotomy or pinning in situ

We undertook a retrospective comparative study of all patients with an unstable slipped capital femoral epiphysis presenting to a single centre between 1998 and 2011. There were 45 patients (46 hips; mean age 12.6 years; 9 to 14); 16 hips underwent intracapsular cuneiform osteotomy and 30 underwent pinning in situ, with varying degrees of serendipitous reduction. No patient in the osteotomy group was lost to follow-up, which was undertaken at a mean of 28 months (11 to 48); four patients in the pinning in situ group were lost to follow-up, which occurred at a mean of 30 months (10 to 50). Avascular necrosis (AVN) occurred in four hips (25%) following osteotomy and in 11 (42%) following pinning in situ. AVN was not seen in five hips for which osteotomy was undertaken > 13 days after presentation. AVN occurred in four of ten (40%) hips undergoing emergency pinning in situ, compared with four of 15 (47%) undergoing non-emergency pinning. The rate of AVN was 67% (four of six) in those undergoing pinning on the second or third day after presentation.

Pinning in situ following complete reduction led to AVN in four out of five cases (80%). In comparison, pinning in situ following incomplete reduction led to AVN in 7 of 21 cases (33%). The rate of development of AVN was significantly higher following pinning in situ with complete reduction than following intracapsular osteotomy (p = 0.048). Complete reduction was more frequent in those treated by emergency pinning and was strongly associated with AVN (p = 0.005).

Non-emergency intracapsular osteotomy may have a protective effect on the epiphyseal vasculature and should be undertaken with a delay of at least two weeks. The place of emergency pinning in situ in these patients needs to be re-evaluated, possibly in favour of an emergency open procedure or delayed intracapsular osteotomy. Non-emergency pinning in situ should be undertaken after a delay of at least five days, with the greatest risk at two and three days after presentation. Intracapsular osteotomy should be undertaken after a delay of at least 14 days. In our experience, closed epiphyseal reduction is harmful.

Cite this article: Bone Joint J 2015;97-B:412–19.

Surgery for slipped capital femoral epiphysis in adolescents

The treatment of slipped capital femoral epiphysis (SCFE) in adolescents remains controversial. The goal of initial treatment is to prevent further slippage of the epiphysis. In mild forms, both stable and unstable, in situ fixation is widely accepted as the reference treatment. In contrast, several techniques are available for stable moderate-to-severe SCFE. In unstable moderate-to-severe SCFE, emergent reduction with decompression and internal fixation is currently the preferred method. Selection of the surgical technique rests on an appraisal of advantages versus drawbacks. The goal of this review is to discuss the various surgical methods available for SCFE in adolescents.

The modified Dunn procedure for unstable slipped capital femoral epiphysis: a multicenter perspective

BACKGROUND

The modified Dunn procedure has rapidly gained popularity as a treatment for unstable slipped capital femoral epiphysis (SCFE), but limited data exist regarding its safety and efficacy. The purpose of this study was to present results and complications following this procedure in a large multicenter series.

METHODS

We reviewed the outcomes of all patients who had been treated with the modified Dunn procedure by five surgeons from separate tertiary-care institutions. All slipped capital femoral epiphyses were defined as unstable according to the Loder criteria. Patients with less than one year of follow-up and those with an underlying endocrinopathy or syndrome were excluded. All surgical procedures were performed by pediatric orthopaedic surgeons who had specific training in the modified Dunn procedure. Operative reports, outpatient records, and follow-up radiographs were used to determine the demographic information, type of fixation, final slip angle, presence of osteonecrosis, and any additional complications. Standardized surveys were administered to determine the pain level (0 to 10 scale), satisfaction (0 to 100 scale), function (modified Harris hip score, 0 to 91 scale), and activity level (UCLA [University of California Los Angeles] activity score, 0 to 10 scale) at time of the most recent follow-up.

RESULTS

Twenty-seven patients (twenty-seven hips) with a mean of 22.3 months (range, twelve to forty-eight months) of follow-up met the inclusion criteria. Four patients (15%) had broken implants at three to eighteen weeks after surgery and required revision fixation. Seven patients (26%) developed osteonecrosis at a mean of 21.4 weeks (range, ten to thirty-nine weeks), with each surgeon having at least one case of osteonecrosis. The mean slip angle at the time of the most recent follow-up was 6° (95% confidence interval, 2° to 11°). Patients who did not develop osteonecrosis had significantly better clinical results compared with those who developed osteonecrosis, as demonstrated by a lower mean pain score (0.3 compared with 3.1, p = 0.002), higher level of satisfaction (97.1 compared with 65.8, p = 0.001), higher modified Harris hip score (88.0 compared with 60.0, p = 0.001), and higher UCLA activity score (9.3 compared with 5.9, p = 0.031).

CONCLUSIONS

This largest reported series of unstable slipped capital femoral epiphyses treated with the modified Dunn procedure demonstrated that the procedure is capable of restoring anatomy and preserving function after a slip but that implant complications and osteonecrosis can and do occur postoperatively.

Slipped upper femoral epiphysis: Outcome after in situ fixation and capital realignment technique

BACKGROUND

Slipped upper femoral epiphysis (SUFE) is the gradually acquired malalignment of the upper femoral epiphysis (capital) and the proximal femoral metaphysis. SUFE is uncommon in India, and there are no previous studies on outcome and clinical characteristics of patients with SUFE from India. This study evaluates the presentation, disease associations and outcome of SUFE from a tertiary care centre in India.

MATERIALS AND METHODS

Twenty six consecutive children with SUFE seen over a period of 4 years were reviewed. The clinical presentations, severity of the slip, surgical interventions (n=30) were assessed. Twenty one boys and five girls with a mean age 13.1 years (range 10-16 years) were included in the study. Four children had bilateral involvement. There were 4 rural and 22 urban children from the eastern and southern states of the country. The presentation was acute in 7, acute on chronic in 5, and chronic in 14, with a mean duration of symptoms of 51 days (range 3-120 days). Slips were stable in 16 and unstable in 10 children. Two children had adiposogenital syndrome. Body mass index was high in 12 out of 23 children. Vitamin D levels were low in 20 out of 21 children, with a mean vitamin D level of 12.61 ± 5 ng/ml. Eighteen children underwent in situ pinning. Eight children underwent capital realignment.

RESULTS

Clinical outcome as assessed by Merle d' Aubigne score was excellent in 6, good in 10, fair in 6 and poor in 1. Half of the in situ fixation patients underwent osteoplasty procedure for femoroacetabular impingement and 5 more were symptomatic. The head neck offset and α angle after in situ pinning were -1.12 ± 3 mm and 66.05 ± 9.7°, respectively and this improved to 8.7 mm and 49°, respectively, after osteoplasty. One child in the pinning group had chondrolysis. Eight patients with severe slip underwent capital realignment. Mean followup was 20.15 months. The anterior head neck offset and α angle were corrected to 6.8 ± 1.72 mm and 44.6 ± 7.0° mm, respectively. Two children with unstable slip in the capital realignment group had avascular necrosis which was diagnosed at presentation by bone scan.

CONCLUSION

High BMI, vitamin D deficiency and endocrine disorders are associated with SUFE in India and should be evaluated as some of these are amenable to prevention and treatment. Most patients treated with in situ pinning developed femoroacetabular impingement. The early results after capital realignment procedure are encouraging and help to avoid a second procedure which is needed in a majority of patients who underwent in situ pinning.

Open reduction and internal fixation of unstable slipped capital femoral epiphysis by means of surgical dislocation does not decrease the rate of avascular necrosis: a preliminary study

PURPOSE

The treatment of unstable slipped capital femoral epiphysis (SCFE) remains controversial. Surgical dislocation and open reduction has the potential to significantly reduce the rate of avascular necrosis (AVN) by allowing direct preservation of the femoral head blood supply. The purpose of this study was to determine if open reduction of the unstable SCFE by means of surgical hip dislocation reduced the risk of AVN compared with closed reduction and percutaneous pinning.

METHODS

We reviewed the medical records and radiographs of patients treated at our institution between the years 2000 and 2008. Sex, age, side of slip, precipitating event, pre- and post-operative anterior physeal separation (APS) and slip angle, slip severity, time between inciting event and surgical treatment, number of screws used, development of AVN, and need for subsequent surgery were evaluated. Statistical analysis was performed to compare risk factors and occurrence of AVN.

RESULTS

From 2004 to 2008, we treated 12 patients with unstable SCFEs: six had closed reduction and percutaneous pinning and six underwent open reduction by means of surgical hip dislocation. There were no statistically significant differences between the two groups regarding sex, age, slip angle, APS, time to surgery, and AVN rate. At follow-up, 4 (66.7 %) patients had AVN in the group which had open reduction, while 2 (33.3 %) patients had AVN in the group which underwent closed reduction. (p = 0.57).

CONCLUSIONS

Open reduction of the unstable SCFE by means of surgical dislocation of the hip does not decrease the rate of AVN when compared to closed reduction.

Slipped capital femoral epiphysis: reduction as a risk factor for avascular necrosis

Complication rates after the treatment of slipped capital femoral epiphysis (SCFE) were retrospectively evaluated to identify possible risk factors. Twenty-six patients with SCFE underwent reduction and fixation with a single screw or multiple wires. The prevalence of avascular necrosis (AVN) of the hip or chondrolysis was 14.8 and 3.6%, respectively. The degree of SCFE (P=0.050) and reduction before the seventh day after the slip (P=0.028) were associated with AVN. The risk factors for AVN were found to be a higher grade of SCFE correction and reduction between the second and the seventh day after SCFE.

Intracapsular hip pressures in a porcine model: does position and volume matter?

This study outlines a relationship between joint volume, positioning, and intracapsular pressure in a healthy hip. After measuring the native intracapsular pressure in 12 porcine specimens, each joint was injected with radio-opaque-colored saline as pressures were measured. At 20 mmHg, the hip was placed in its position of ease and then in differing positions while pressures were recorded. Position significantly altered pressures, with the lowest values in neutral and the highest in hyperextension (P<0.001). Extreme hip positions may be detrimental because of high pressures created within the joint, possibly explaining complications associated with some hip diagnostic and treatment methods.

Treatment of SCFE in a healthy 5-year-old child: case report and review

Slipped capital femoral epiphysis is a common adolescent hip disorder and when patients present at an age younger than 10 years, it is atypical and there is often some identifiable associated metabolic or endocrinologic abnormality. We present the case of a 5-year-old boy with idiopathic bilateral slipped capital femoral epiphysis. This patient underwent staged bilateral pinning in situ using a uniquely modified screw where the distal threads were machined-off for smooth fixation across the physis. The patient had an unremarkable postoperative course and showed evidence of remodeling and patent physes at 1-year follow-up.

Bilateral unstable slipped capital femoral epiphysis: a look at risk factors

Unstable slipped capital femoral epiphysis can have disastrous complications including osteonecrosis and chondrolysis. It has been shown that 20% to 80% of patients may develop a contralateral slip ≤18 months after diagnosis. The purpose of this article is to report and characterize patients who developed bilateral unstable slips. After Institutional Review Board approval, the patients included were only those with bilateral unstable slipped capital femoral epiphyses. A minimum 2-year follow-up was required. Seven patients, all female, were included in the study, with an average age of 11.4 years at the time of their first slips. The interval between slips averaged 127 days (range, 0-245 days). All but 1 patient presented with a severe slip. The second slip was also severe in 3 patients and less severe in 4 patients. The triradiate cartilage was open in 3 patients. Two patients required corrective osteotomies. Chondrolysis developed in 2 patients with no osteonecrosis reported. The incidence of bilateral unstable slips ranged from 4% to 20% of all unstable slipped capital femoral epiphyses based on our findings. Skeletal immaturity was not a risk factor. The surgeon must be vigilant for the possibility of bilateral slips. The family must be instructed on precautions patients must take while recuperating from unstable slipped capital femoral epiphyses. Contralateral fixation of the unaffected side may be warranted in patients with initial severe unstable slipped capital femoral epiphyses to prevent this condition.

Avascular necrosis most common indication for hip arthroplasty in patients with slipped capital femoral epiphysis

BACKGROUND

Recently, much attention has been focused on the prevention of arthritis after slipped capital femoral epiphysis (SCFE). Little, however, is published on which subset of SCFE patients eventually require hip replacement, how soon arthroplasty is required, and the long-term outcomes after arthroplasty.

METHODS

A hip registry database at a tertiary referral center was searched for all primary hip arthroplasties in patients with a confirmed childhood diagnosis of SCFE.

RESULTS

From 1954-2007, 38 hips in 33 patients underwent arthroplasty, including total hip arthroplasty (28), hip resurfacing (8), and hemiarthroplasty (2) for the diagnosis of SCFE. During this time period, over 33,000 primary total hip arthroplasties were carried out at our center. Underlying diagnoses included avascular necrosis or chondrolysis in 25 hips and degenerative changes and/or impingement in 13 hips. The slip severity in 20 cases was severe, 4 moderate, 7 mild, and 7 hips had unknown slip severity. Half of the slips (7/14) in the degenerative group were mild or moderate. Fourteen (70%) of the 20 severe slips and 10 (71%) of the 14 acute or acute-on-chronic slips presented for arthroplasty with the diagnosis of avascular necrosis. Avascular necrosis was associated with a severe slip (P=0.03) and an acute or acute-on-chronic presentation (P=0.008). With the exception of 2 mild slips treated nonoperatively, all slips underwent either pin fixation (27) or primary osteotomy (9). Mean time from slip to arthroplasty was 7.4 years in patients with AVN or chondrolysis, compared with 23.6 years in patients with degenerative change (P<0.0002). Mean age at arthroplasty was 20 years in the AVN or chondrolysis group compared with 38 years in the degenerative group (P<0.0001). Sixteen hips required revision arthroplasty at a mean of 11.6 years postoperatively, most commonly for component loosening and/or polyethylene wear. Kaplan Meier 5-year survival free from revision for all causes was 87% overall and 95% in the total hip arthroplasty subset.

CONCLUSIONS

The majority of hip arthroplasties in patients with slipped capital femoral epiphysis were carried out for the indication of avascular necrosis rather than degenerative changes related to femoroacetabular impingement. We found a moderately high revision rate in SCFE patients undergoing total hip arthroplasty or other joint replacement.

LEVEL OF EVIDENCE

IV, case series.

The unstable slipped capital femoral epiphysis: risk factors for osteonecrosis

BACKGROUND

The incidence of avascular necrosis (AVN) after unstable slipped capital femoral epiphysis (SCFE) varies widely in the literature (10% to 60%), and few studies have examined why certain unstable slips develop osteonecrosis whereas others do not. Our purpose was to determine risk factors for developing AVN after unstable SCFE.

METHODS

We reviewed all unstable SCFEs treated primarily at our center. Medical records were reviewed to determine weight-percentile, age, length of prodromal symptoms, and time to treatment. Operative notes were used to classify treatment as either: (group 1) in situ screw fixation, (group 2) purposeful or inadvertent closed reduction and screw fixation, or (group 3) open reduction and internal fixation, and to determine whether or not the joint was decompressed during surgery. Preoperative radiographs were used to measure slip angle and percent translation. For group 2, these were compared with postoperative radiographs to calculate a Deltaslip angle and Deltatranslation. Student t tests and Fisher exact tests were used for statistical analysis.

RESULTS

Of the 70 patients in our series, 14 developed AVN (20%). On the basis of treatment, 3 of 16 patients in group 1 (19%), 10 of 38 patients in group 2 (26%), and only 1 of 16 patients in group 3 (6%) developed AVN. Patients who developed osteonecrosis were significantly younger (11.67 y vs. 12.83 y, P=0.04) and had a significantly shorter duration of prodromal symptoms (17.5 d vs. 65.9 d, P=0.03) compared with those who did not develop AVN. None of the other factors were found to be significant. In a subgroup analysis looking solely at group 2 patients, those who developed AVN had a significantly higher initial slip angle compared with those who did not (62 degrees vs. 51 degrees, P=0.03).

CONCLUSIONS

In this, the largest reported series of unstable slips treated with internal fixation, AVN seemed more likely to develop in younger patients with a shorter duration of prodromal symptoms. Patients undergoing open reduction may have a lower incidence of AVN, but our limited power precludes definitive conclusions.

LEVEL OF EVIDENCE

Level IV (case series).