Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis

Medium-long-term follow-up of slipped capital femoral epiphysis treated with in situ fixation and patient-acceptable symptom state evaluation

This study evaluates the Patient Acceptable Symptom State (PASS) in patients with slipped capital femoral epiphysis (SCFE) treated with in situ fixation, focusing on medium to long-term outcomes and quality of life. Its primary goal is to establish a subjective well-being cutoff, using subjective methods and the iHOT33 scale, for assessing patients in future studies. Additionally, it explores functionality differences between mild and moderate-severe SCFE, case series epidemiology and potential complications. A retrospective analysis of 63 patients (73 hips), treated for SCFE between 2000 and 2017 at our facility using in situ fixation, was conducted. These patients underwent clinical, anamnestic, and radiological assessments, with PASS determined based on iHOT33 questionnaire results and statistical analysis. The mean age at surgery was 12.95 years (±1.64, range 9-17), with an average follow-up of 11 years (±4.60, range 5-20). At follow-up, 87% of patients reported achieving PASS, with higher iHOT33 scores correlating to PASS. A cutoff of >68 on the iHOT33 scale showed strong predictive ability for assessing PASS (area under the curve 0.857, 88.89% sensitivity, 79.69% specificity). The findings indicate that 87% of patients achieved PASS at medium to long-term follow-up, with better clinical function than those who did not report PASS. The iHOT33 scale's effectiveness in predicting PASS, especially with a cutoff of >68, suggests this method's efficacy. Given these positive outcomes, including in moderate-severe cases treated with in situ fixation, this approach is considered a viable therapeutic option.

The McMaster osteotomy-a novel surgical treatment to chronic slipped capital femoral epiphysis: description of surgical technique and case study

Slipped capital femoral epiphysis (SCFE) is a common adolescent hip disorder that can lead to complex proximal femur deformities and devastating consequences such as avascular necrosis, femoroacetabular impingement syndrome and early-onset osteoarthritis. Existing surgical techniques are often insufficient to fully address the constellation of multiplanar deformities in patients with severe SCFE. Therefore, the McMaster Osteotomy, a novel intertrochanteric proximal femur osteotomy, was developed to improve anatomic correction and hip mechanics in patients with chronic SCFE. The McMaster Osteotomy was implemented in two patients (A: 16-year-old male, B: 17-year-old female) with proximal femur deformities due to chronic SCFE. Surgical planning was facilitated with a 3D-printed pelvic model generated from a CT scan of a patient with the SCFE deformity. Patient B also underwent concurrent arthroscopic osteochondroplasty and labral repair. Pre- and post-operative function and radiographic measurements were recorded. Post-operatively, patient A's neck-shaft angle improved from 125° to 136°, Southwick angle from 52° to 33°, neck length from 66 mm to 80 mm and hip internal rotation from 5° to 25°. Patient B's post-operative neck-shaft angle improved from 122° to 136°, Southwick angle from 25° to 15°, neck length from 76 mm to 84 mm, hip internal rotation from 5° to 20° and alpha angle from 87.6° to 44.3°. Both patients are pain-free and have obtained full union of their osteotomies. The McMaster Osteotomy is a versatile technique that can produce a more anatomic reconstruction of hip anatomy and restoration of abductor mechanics. As an extracapsular technique, the risk of femoral head avascular necrosis is minimized.

How Safe and Technical Is Modified Dunn Osteotomy in the Management of Patients with SCFE: A Clinical Trial with Short-Term Follow-Up

Objective

Over the last decade, modified Dunn osteotomy has been widely used in the management of slipped capital femoral epiphysis (SCFE) with varying degrees of complications. Different conclusions have been adopted. Our study represented our experience in using such a technique in stable and unstable SCFE and tried to determine its safety and applicability for routine practice.

Methods

Our study adopted an interventional prospective design performed on 24 hips divided evenly between both sexes with a mean age of 13.25. On the Southwick classification, the cases were distributed between moderate and severe, which constituted 41.7% and 58.33%, respectively. Three quarters of the study subjects were stable according to the Loder classification. Each underwent modified Dunn osteotomy after a safe surgical hip dislocation.

Results

Over the period of about 1-year follow-up, clinical evaluation was performed by examining the surgical site and assessing the legs' length, range of hip movement, Harris hip score, and iHOT-12 score. Radiological assessment was performed by calculation of slip angle from the frog lateral view, assessment of union, and occurrence of any complications. The study showed that there was significant improvement in patients in terms of radiological and clinical outcomes, with the occurrence of AVN in 16.7% of cases (4 out of 24). All cases of AVN occurred in unstable hips.

Conclusion

Despite the complication of AVN, we believe the results of this study add to the current literature which suggests that modified Dunn osteotomy is an effective and safe technique for the management of moderate and severe SCFE. This trial is registered with PACTR202312819351504.

3D printed patient-specific fixation plates for the treatment of slipped capital femoral epiphysis: Topology optimization vs. conventional design

Orthopedic plates are commonly used after osteotomies for temporary fixation of bones. Patient-specific plates have recently emerged as a promising fixation device. However, it is unclear how various strategies used for the design of such plates perform in comparison with each other. Here, we compare the biomechanical performance of 3D printed patient-specific bone plates designed using conventional computer-aided design (CAD) techniques with those designed with the help of topology optimization (TO) algorithms, focusing on cases involving slipped capital femoral epiphysis (SCFE). We established a biomechanical testing protocol to experimentally assess the performance of the designed plates while measuring the full-field strain using digital image correlation. We also created an experimentally validated finite element model to analyze the performance of the plates under physiologically relevant loading conditions. The results indicated that the TO construct exhibited higher ultimate load and biomechanical performance as compared to the CAD construct, suggesting that TO is a viable approach for the design of such patient-specific bone plates. The TO plate also distributed stress more evenly over the screws, likely resulting in more durable constructs and improved anatomical conformity while reducing the risk of screw and plate failure during cyclic loading. Although differences existed between finite element analysis and experimental testing, this study demonstrated that finite element modelling can be used as a reliable method for evaluating and optimizing plates for SCFE patients. In addition to enhancing the mechanical performance of patient-specific fixation plates, the utilization of TO in plate design may also improve the surgical outcome and decrease the recovery time by reducing the plate and incision sizes.

Effects of joint loading on the development of capital femoral epiphysis morphology

INTRODUCTION

The deleterious influence of increased mechanical forces on capital femoral epiphysis development is well established; however, the growth of the physis in the absence of such forces remains unclear. The hips of non-ambulatory cerebral palsy (CP) patients provide a weight-restricted (partial weightbearing) model which can elucidate the influence of decreased mechanical forces on the development of physis morphology, including features related to development of slipped capital femoral epiphysis (SCFE). Here we used 3D image analysis to compare the physis morphology of children with non-ambulatory CP, as a model for abnormal hip loading, with age-matched native hips.

MATERIALS AND METHODS

CT images of 98 non-ambulatory CP hips (8-15 years) and 80 age-matched native control hips were used to measure height, width, and length of the tubercle, depth, width, and length of the metaphyseal fossa, and cupping height across different epiphyseal regions. The impact of age on morphology was assessed using Pearson correlations. Mixed linear model was used to compare the quantified morphological features between partial weightbearing hips and full weightbearing controls.

RESULTS

In partial weightbearing hips, tubercle height and length along with fossa depth and length significantly decreased with age, while peripheral cupping height increased with age (r > 0.2, P < 0.04). Compared to normally loaded (full weightbearing) hips and across all age groups, partially weightbearing hips' epiphyseal tubercle height and length were smaller (P < .05), metaphyseal fossa depth was larger (P < .01), and posterior, inferior, and anterior peripheral cupping heights were smaller (P < .01).

CONCLUSIONS

Smaller epiphyseal tubercle and peripheral cupping with greater metaphyseal fossa size in partial weightbearing hips suggests that the growing capital femoral epiphysis requires mechanical stimulus to adequately develop epiphyseal stabilizers. Deposit low prevalence and relevance of SCFE in CP, these findings highlight both the role of normal joint loading in proper physis development and how chronic abnormal loading may contribute to various pathomorphological changes of the proximal femur (i.e., capital femoral epiphysis).

Modified Dunn Technique for Unstable Slipped Capital Femoral Epiphysis: A Midterm Single Center Experience

Objective  To evaluate the safety and reproducibility of the surgery for unstable slipped capital femoral epiphysis (SCFE) through the modified Dunn technique in a single center cohort from Brazil. Methods  We retrospectively analyzed a cohort of patients submitted to this procedure by a single surgeon who was a hip preservation specialist. Demographic data and radiographic angles were evaluated for the relative risk (RR) of avascular necrosis (AVN) using a log-binomial regression model with simple and random effects. Results  Among the 30 patients (30 hips) with a mean age of 11.79 years at the time of the operation, there were 17 boys and 18 left hips, which were operated on in a mean of 11.5 days after the slip. The mean follow-up was of 38 months. The preoperative Southwick angle averaged 60.69° against 4.52° postoperatively ( p  < 0.001). A larger preoperative slip angle was associated with the development of AVN (RR: 1.05; 95% confidence interval [95%CI]: 1.02-1.07; p  < 0.01). The overall AVN rate was of 26.7%. Function was good or excellent in 86% of uncomplicated hips, and poor in 87.5% of the partients who developed AVN, as graded by the Harris Hip Score. There was no statistical relationship between epiphyseal bleeding and AVN development ( p  = 0.82). Conclusion  The modified Dunn technique is associated with restoration of the femoral alignment and function after unstable SCFE, when uncomplicated. Moreover, it was shown to be reproducible in our population, with a rate of 26% of femoral head necrosis.

Comparing pinning in situ and capital realignment procedures for severe, stable slipped capital femoral epiphysis: a systematic review

In severe, stable slipped capital femoral epiphysis, it is unclear whether pinning in situ (PIS) or capital realignment procedures (CRPs) are superior. Our primary aim was to compare patient-reported outcome measures (PROMs) following each strategy. Secondary aims were to compare rates of femoral head avascular necrosis (AVN) and complications. MEDLINE, Embase and Cochrane databases were searched according to an agreed strategy. Narrative review articles, case reports, letters to the editor and articles not written in English were excluded. The risk of bias was assessed using the Newcastle-Ottawa Scale. Of the 132 citations identified, 127 were excluded following de-duplication and application of the exclusion criteria. Three observational studies comparing PIS with CRP and two case series considering CRP alone were identified. One article was considered fair quality, and four articles were considered poor. In total, 198 hips from five studies were included (66 PIS, 132 CRP). PIS was associated with moderate-good functional outcomes, and CRP with good-high outcomes. Two comparative studies reported significantly better PROMs following CRP. AVN was reported in 1.5% following PIS and 10.6% following CRP. Regarding other complications, chondrolysis occurred in 3.0% following PIS and 2.4% following CRP. Femoroacetabular impingement rates were markedly higher following PIS (60.6% versus 2.3%). Reoperation rates were also greater following PIS (34.5% versus 13.3%). PIS tends to be associated with favourable AVN rates, but CRP with favourable PROMs and complication rates. However, comparisons were drawn from heterogeneous studies lacking long-term follow-up. Further high-quality research is required.

The Free-Gliding screw for slipped capital femoral epiphysis : is it safe, does it glide, and does age matter?

AIMS

Fixation techniques used in the treatment of slipped capital femoral epiphysis (SCFE) that allow continued growth of the femoral neck, rather than inducing epiphyseal fusion in situ, have the advantage of allowing remodelling of the deformity. The aims of this study were threefold: to assess whether the Free-Gliding (FG) SCFE screw prevents further slip; to establish whether, in practice, it enables lengthening and gliding; and to determine whether the age of the patient influences the extent of glide.

METHODS

All patients with SCFE who underwent fixation using FG SCFE screws after its introduction at our institution, with minimum three years' follow-up, were reviewed retrospectively as part of ongoing governance. All pre- and postoperative radiographs were evaluated. The demographics of the patients, the grade of slip, the extent of lengthening of the barrel of the screw and the restoration of Klein's line were recorded. Subanalysis was performed according to sex and age.

RESULTS

A total of 19 hips in 13 patients were included. The mean age of the patients at the time of surgery was 11.5 years (9 to 13) and the mean follow-up was 63 months (45 to 83). A total of 13 FG SCFE screws were used for the fixation of mild or moderate SCFE, with six contralateral prophylactic fixations. No hip with SCFE showed a further slip after fixation and there were no complications. Lengthening occurred in 15 hips (79%), with a mean lengthening of the barrel of 6.8 mm (2.5 to 13.6) at final follow-up. Remodelling occurred in all hips with lengthening of the barrel. There was statistically more lengthening in patients who were aged < 12 years, regardless of sex (p = 0.002).

CONCLUSION

The FG SCFE screw is effective in preventing further slip in patients with SCFE. Lengthening of the barrel occurred in most hips, and thus allowed remodelling. This was most marked in younger children, regardless of sex. Based on this study, this device should be considered for use in patients with SCFE aged < 12 years instead of standard pinning in situ.Cite this article: Bone Joint J 2023;105-B(2):215-219.

Increasing incidence of slipped capital femoral epiphysis in Trinidad and Tobago: A 50-year review

Slipped Capital Femoral Epiphysis (SCFE) is a physeal disorder of the proximal femur. Misdiagnosis and late treatment are associated with poorer outcomes. The epidemiology and delays in treatment of the disease between 1968 and 2018 were investigated in North Trinidad. The number of cases presenting annually has increased over the decades and the incidence between 2008-2018 was 2.2 cases per 100 000 per year. Almost 70% of cases were above the 95^th percentile for body weight. Delay in treatment from onset of symptoms was 278 ± 258 days. Awareness of the risk factors and clinical presentation of SCFE may facilitate early diagnosis and treatment, and prevent severe hip disability in adulthood.

Mid-term results of subcapital realignment of chronic slipped capital femoral epiphysis using surgical hip dislocation: a prospective case series

BACKGROUND

Slipped capital femoral epiphysis (SCFE) requires surgical treatment when diagnosed. The surgical management of moderate to severe SCFE remains an area of controversy among pediatric orthopedic surgeons. The severity of slippage, the viability of the femoral epiphysis, and the method of surgical management determine the long-term clinical and radiographical outcome. This study sought to evaluate the mid-term results of subcapital realignment of chronic stable slipped femoral epiphysis with open physis using surgical hip dislocation.

MATERIALS AND METHODS

This study was a prospective case series of adolescents with moderate or severe degrees of chronic SCFE who had undergone subcapital osteotomy using the surgical hip dislocation technique. The Harris Hip Score (HHS) was used to assess functional outcomes at 6 years of follow-up. A HHS of ≥ 80 points was considered satisfactory. Postoperative radiological outcomes were evaluated using epiphyseal-shaft angles and alpha angles. Postoperative complications were observed.

RESULTS

This study included 40 patients, 32 (80%) males and 8 (20%) females, with a mean age of 14.1 ± 1.8 years. There was a statistically significant improvement in the mean HHS from 45 ± 12.3 preoperatively to 91.8 ± 11.6 points at 6 years of follow-up. The mean epiphyseal-shaft angle reduced from 60.5 ± 15.3° preoperatively to 10.3 ± 2.4° postoperatively, P < 0.001. The mean alpha angle reduced from 72.5 ± 10.1° preoperatively to 40.4 ± 6.4°, P < 0.001. Four (10%) patients showed femoral head avascular necrosis (AVN).

CONCLUSIONS

Subcapital realignment of chronic SCFE can achieve satisfactory clinical and radiological outcomes, but femoral head AVN remains a risk. Level of evidence Level IV.

Limited Hip Flexion and Internal Rotation Resulting From Early Hip Impingement Conflict on Anterior Metaphysis of Patients With Untreated Severe SCFE Using 3D Modelling

INTRODUCTION

Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in adolescent patients that can result in complex 3 dimensional (3D)-deformity and hip preservation surgery (eg, in situ pinning or proximal femoral osteotomy) is often performed. But there is little information about location of impingement.Purpose/Questions: The purpose of this study was to evaluate (1) impingement-free hip flexion and internal rotation (IR), (2) frequency of impingement in early flexion (30 to 60 degrees), and (3) location of acetabular and femoral impingement in IR in 90 degrees of flexion (IRF-90 degrees) and in maximal flexion for patients with untreated severe SCFE using preoperative 3D-computed tomography (CT) for impingement simulation.

METHODS

A retrospective study involving 3D-CT scans of 18 patients (21 hips) with untreated severe SCFE (slip angle>60 degrees) was performed. Preoperative CT scans were used for bone segmentation of preoperative patient-specific 3D models. Three patients (15%) had bilateral SCFE. Mean age was 13±2 (10 to 16) years and 67% were male patients (86% unstable slip, 81% chronic slip). The contralateral hips of 15 patients with unilateral SCFE were evaluated (control group). Validated software was used for 3D impingement simulation (equidistant method).

RESULTS

(1) Impingement-free flexion (46±32 degrees) and IRF-90 degrees (-17±18 degrees) were significantly ( P <0.001) decreased in untreated severe SCFE patients compared with contralateral side (122±9 and 36±11 degrees).(2) Frequency of impingement was significantly ( P <0.001) higher in 30 and 60 degrees flexion (48% and 71%) of patients with severe SCFE compared with control group (0%).(3) Acetabular impingement conflict was located anterior-superior (SCFE patients), mostly 12 o'clock (50%) in IRF-90 degrees (70% on 2 o'clock for maximal flexion). Femoral impingement was located on anterior-superior to anterior-inferior femoral metaphysis (between 2 and 6 o'clock, 40% on 3 o'clock and 40% on 5 o'clock) in IRF-90 degrees and on anterior metaphysis (40% on 3 o'clock) in maximal flexion and frequency was significantly ( P <0.001) different compared with control group.

CONCLUSION

Severe SCFE patients have limited hip flexion and IR due to early hip impingement using patient-specific preoperative 3D models. Because of the large variety of hip motion, individual evaluation is recommended to plan the osseous correction for severe SCFE patients.

LEVEL OF EVIDENCE

Level III.

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.

Case report: Fluoroscopic-assisted closed reduction and minimally invasive femoral capital physeal fracture repair in four calves

Objective

To describe a minimally invasive osteosynthesis (MIO) femoral capital physeal fracture (FCPF) repair technique using multiple smooth Steinmann pins in four calves.

Study design

Case series.

Animal

Four calves (< 60 days of age).

Methods

Medical records at a single referral hospital were searched for calves that had minimally invasive osteosynthesis (MIO) femoral capital physeal fracture (FCPF) repair performed using multiple Steinmann pins between 2020 and 2021. Calves receiving alternative repair, euthanasia without repair, or > 60 days of age were excluded. Medical records were reviewed together the following information: inciting FCPF cause, patient signalment, clinical sign duration pre-admission, history of dystocia, and any pre-admission treatment. Preoperative parameters collected included packed cell volume (PCV), serum total solids (TS), additional bloodwork when available, peripheral blood glucose, antimicrobial therapy, and analgesic medications. Preoperative coxofemoral radiographic images of all calves were obtained.

Results/outcome

Four calves were presented with severe hind limb lameness from varying etiologies. FCPF was diagnosed in all calves via radiograph. All FCPFs were repaired with an MIO repair technique using multiple Steinmann pins. Intraoperative fracture reduction and fixation were deemed appropriate by the attending surgeon with the use of fluoroscopy. Postoperatively, all calves retained normal weight bearing and were ambulating. One calf died postoperatively due to an unrelated comorbidity (severe bronchopneumonia and hyperkalemia). The three remaining calves survived to hospital discharge and were ambulating normally with an adequate range of motion at the time of discharge. Long-term follow-up reports were available for two cases, which revealed long-term survival at 210- and 146-days. Owners reported good ambulation, and one of the calves was placed in the show ring and was performing. However, one calf was lost to long-term follow-up.

Conclusion

MIO FCPF repair with multiple Steinmann pins, previously described in small animal species, can be implemented for FCPF repair in young calves.

Clinical impact

This case series provides a foundation for minimally invasive osteosynthesis technique translation to large animal juveniles and reports an alternative MIO technique for capital physeal closed fracture repair in calves.

The readability of online patient education materials for slipped capital femoral epiphysis

Given the long-term complications of undiagnosed slipped capital femoral epiphysis (SCFE) and the importance of readable health information materials on positive, equitable health outcomes, the objective of this study was to determine if the online patient education materials regarding SCFE are written at or below accepted recommendations. The secondary objective was to determine whether the readability of these materials varied when stratified by the type of website. 'Slipped capital femoral epiphysis', 'SCFE', and 'slipped femoral head' were used as search queries in three common search engines. The readability of each website was evaluated using five established metrics, and the scores were compared by website type and by the complexity of the search query. In this study of 53 unique websites about SCFE, we demonstrated that only one of the web pages was written at the recommended sixth-grade level, and the mean reading level of the online material was above the 10th-grade level. Post hoc testing showed that only websites associated with pediatric academic institutions were written at a significantly lower grade level than general health websites [P < 0.05 for all, range (0.003, 0.04)]. The materials about SCFE that are available to patients and their families continue to be written at an inappropriate level. To increase accessibility and allow for equitable long-term health outcomes, physicians, universities, hospitals and medical societies must ensure that they produce readable education to increase patients' understanding of SCFE, its symptoms and available treatment options. Future studies evaluating progress regarding these metrics are warranted.

Novel Application of Immersive Virtual Reality Simulation Training: A Case Report

Case:

A percutaneous pinning of a slipped capital femoral epiphysis is described after the use of immersive virtual reality (iVR) training. This case report documents the first reported example of an immediate translation of surgical skill from iVR to the operating room.

Conclusion:

There is increasing evidence for the use of iVR in orthopaedic education. Several randomized controlled trials demonstrate improved trainee performance relative to control when measured in analogous operating room assessments. This is the first case report demonstrating direct patient care after the use of iVR. The implications of cost-effectiveness through skill transfer and patient safety are highlighted.

Intraobserver and Interobserver Reliability of the Peritubercle Lucency Sign in Slipped Capital Femoral Epiphysis

BACKGROUND

An area of enlargement of the metaphyseal socket around the epiphyseal tubercle, termed the peritubercle lucency sign, has recently been introduced as a possible predictor of contralateral slipped capital femoral epiphysis in patients with previous unilateral slipped capital femoral epiphysis. This study aimed to assess intraobserver and interobserver reliability for detecting the presence or absence of the peritubercle lucency sign.

METHODS

Thirty-five radiographs were presented to 6 fellowship-trained pediatric orthopaedic surgeons on 2 separate occasions 30 days apart, ensuring that the images were shown in a different order on the second exposure. Both times the reviewers recorded whether the peritubercle lucency sign was present or absent in each of the radiographs. Statistical analysis was performed to determine the intraobserver and interobserver reliability.

RESULTS

In the intraobserver analysis, percent agreement between the first and second time the radiographs were reviewed varied between 62.9% and 85.7%, for an average intraobserver agreement of 74.8%. κ values for the 6 reviewers varied between 0.34 and 0.716, with an average intraobserver κ value of 0.508. The interobserver percent agreement was 40.0% for the first time the radiographs were reviewed, 42.9% the second time, and the overall interobserver percent agreement was 29%. The interobserver κ value was 0.44 the first time the radiographs were reviewed, 0.45 the second time, and the overall interobserver κ value was 0.45.

DISCUSSION

On the basis of our findings, the peritubercle lucency has modest intraobserver and interobserver reliability at best and should be used with other currently used factors, such as age, presence of endocrinopathy, status of triradiate cartilage, posterior sloping angle, and modified Oxford score, in determining the need for prophylactic pinning. Further refinement of the definition of the peritubercle lucency sign may be needed to improve agreement and reliability of the sign.

LEVEL OF EVIDENCE

Level III-prognostic study.

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.

Total hip arthroplasty in patients with slipped capital femoral epiphysis: a systematic analysis of 915 cases

There is limited evidence on the outcomes of Total Hip Arthroplasty (THA) in Slipped Capital Femoral Epiphysis (SCFE) patients. This systematic review aims to evaluate the current literature in terms of survival rate, functional outcomes, complications and types of implants of THA in SCFE patients. Following the established methodology of PRISMA guidelines, PubMed, Cochrane library, ScienceDirect and Ovid MEDLINE were systematically searched from inception to September 2018. The search criteria used were: (“total hip arthroplasty’’ OR ‘’total hip replacement’’ OR “hip arthroplasty’’ OR ‘’hip replacement’’) AND (‘’slipped capital femoral epiphysis’’ OR ‘’slipped upper femoral epiphysis’’ OR ‘’femoral epiphysis’’). Ten studies were finally included in the analysis and were qualitatively appraised using the Newcastle-Ottawa tool. Variables were reported differently between studies. The sample size varied from 12 to 374 THAs. A total of 877 patients undergone 915 THAs. The mean reported follow-up ranged from 4.4 to 15.2 years and the mean patients’ age at the time of THA from 26 to 50 years. Four studies specified the type of implants used, with 62% being uncemented, 24% hybrid (uncemented cup/cemented stem) and 14% cemented. All but three studies reported the mean survival of implants that ranged from 64.9% to 94.8%. A limited number of complications were mentioned. There was a tendency for more favorable functional outcomes in modern studies. Modern THA-studies in SCFE patients showed improvement of survivorship, clinical outcomes and patient satisfaction. Future higher-quality studies are necessary to estimate long-term postoperative outcomes better.