Slipped capital femoral epiphysis: relevant pathophysiological findings with open surgery

Modified Dunn Procedure for Open Reduction of Chronic Slipped Capital Femoral Epiphysis

Background

Abnormal femoral head anatomy following moderate-to-severe slipped capital femoral epiphysis (SCFE) can lead to femoroacetabular impingement and premature osteoarthritis4-10. Surgical correction at the deformity site through capital reorientation has the potential to fully ameliorate this but has traditionally been associated with high rates of osteonecrosis11-15. The modified Dunn procedure has the potential to restore anatomy in hips with SCFE while protecting the blood supply to the femoral head.

Description

A surgical dislocation of the hip is performed according to the technique described by Ganz et al.16. The remaining posterosuperior portion of the greater trochanter is trimmed to the level of the femoral neck by subperiosteal bone removal performed in an inside-out manner. The periosteum of the femoral neck is gradually elevated. The resulting soft-tissue flap, consisting of the retinaculum and external rotators, holds the blood vessels supplying the epiphysis. The femoral epiphysis is pinned in situ (in unstable cases) with threaded Kirschner wires, the ligamentum teres is transected, and the femoral head is dislocated. With the femoral neck exposed, the epiphysis is gradually mobilized from the metaphysis, allowing exposure of the residual femoral neck and inspection of any posteroinferior callus. To avoid tension on the retinacular vessels during reduction of the epiphysis, the posterior neck callus is completely excised. The remaining physis is removed with use of a burr while holding the epiphysis stable. The epiphysis is gently reduced onto the femoral neck, avoiding tension on the retinacular vessels. If tension is noted, the femoral neck is rechecked for residual callus, which is excised. If no callus is found, the neck may be carefully shortened in order to minimize tension. Epiphyseal fixation is achieved with use of a 3-mm fully threaded wire inserted antegrade through the fovea to the lateral cortex below the greater trochanter. A second wire is inserted retrograde under fluoroscopy. After reducing the hip, the capsule is closed and the greater trochanter is reattached with use of 3.5-mm cortical screws.

Alternatives

Alternatives include nonoperative treatment, in situ fixation (e.g., pinning or screw fixation), gentle closed reduction with pinning, and triplanar trochanteric osteotomy (e.g., Imhauser or Southwick osteotomies).

Rationale

In situ pinning of mild-to-moderate, stable SCFE yields good long-term results with low rates of osteonecrosis9. Treatment of higher-grade SCFE without reduction aims to avoid osteonecrosis and assumes that the proximal femoral deformity will remodel; however, the head-neck offset will remain abnormal, risking impingement and early-onset osteoarthritis5,8. The procedure described in the present article allows anatomic reduction of the epiphysis with a low risk of osteonecrosis. Surgical dislocation of the hip16 with development of an extended retinacular soft-tissue flap17 provides extensive subperiosteal exposure of the circumferential femoral neck and preserves the vulnerable blood supply to the epiphysis18. The Dunn subcapital realignment procedure15 with callus removal and slip angle correction allows anatomic restoration of the proximal femur.

Expected Outcomes

Reported results of various centers performing the procedure vary greatly with regard to the number of hips treated and the follow-up time. Most studies have been retrospective and have lacked a control group. The reported risk of osteonecrosis ranges from 0% to 25.9%19, with the wide range most likely because of the challenging nature of the technique, the low number of cases per surgeon, and the long learning curve associated with the procedure. In centers with extensive experience in pediatric hip-preserving surgery, the reported rate of osteonecrosis is low3. Studies with mid to long-term follow-up have shown no conversion to total hip arthroplasty3,20,21, but residual deformities can persist, and subsequent surgery is possible.

Important Tips

Extensive experience in surgical hip dislocation and retinacular flap development is a prerequisite for successful outcomes and low rates of osteonecrosis.Sufficient callus and physeal remnant resections are needed to avoid tension on the retinacular vessels during epiphyseal reduction.The skin incision should be centered over the greater trochanterThe Gibson interval must be carefully prepared for adequate release and to avoid injury.Tension on the periosteal flap should be avoided to prevent stress on the retinacular vessels.

Acronyms and Abbreviations

AP = anteroposteriorAVN = avascular necrosis (i.e., osteonecrosis)CI = confidence intervalCT = computed tomographyK-wire = Kirschner wireMRI = magnetic resonance imagingOA = osteoarthritisSHD = surgical hip dislocationTHA = total hip arthroplastyVTE = venous thromboembolism.

Limited angular remodelling after in-situ fixation for slipped capital femoral epiphysis : A study on radiographs from the Swedish pediatric orthopaedic quality registry for SCFE

BACKGROUND

In Sweden, most children with slipped capital femoral epiphysis (SCFE) are operated on with a single smooth pin or a short-threaded screw, allowing further growth of the femoral neck. Using the Swedish Pediatric Orthopaedic Quality registry, SPOQ, we investigated whether angular remodelling occurs adjacent to the proximal femoral epiphysis after fixation of SCFE using implants, allowing continued growth of the femoral neck.

METHODS

During 2008-2010 a total national population of 155 children were reported to the SPOQ registry. Following our strict inclusion criteria, radiographs of 51 hips were further assessed. The lateral Head Shaft Angle (HSA), the Nötzli 3-point α-angle, the anatomic α-angle, and the Anterior Offset Ratio (AOR) on the first postoperative radiographs and at follow-up were measured to describe the occurrence of remodelling. Slip severity was categorised as mild, moderate or severe according to postoperative HSA.

RESULTS

Mean and SD values for the change in HSA were 3,7° (5,0°), for 3-point α-angle 6,8° (8,9°), and anatomic α-angle 13,0° (16,3°). The overall increase in AOR was 0,038 (0.069). There were no significant differences between the slip severity groups.

CONCLUSIONS

We found limited angular remodelling after in situ fixation with smooth pins or short threaded screws for SCFE. The angular remodelling and the reduction of the CAM deformity was less than previously described after fixation of SCFE with similar implants. Results about the same magnitude with non-growth sparing techniques suggest that factors other than longitudinal growth of the femoral neck are important for angular remodelling.

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.

Hip Impingement of severe SCFE patients after in situ pinning causes decreased flexion and forced external rotation in flexion on 3D-CT

Introduction

In situ pinning is an accepted treatment for stable slipped capital femoral epiphysis. However, residual deformity of severe slipped capital femoral epiphysis can cause femoroacetabular impingement and forced external rotation.

Purpose/questions

The aim of this study was to evaluate the (1) hip external rotation and internal rotation in flexion, (2) hip impingement location, and (3) impingement frequency in early flexion in severe slipped capital femoral epiphysis patients after in situ pinning using three-dimensional computed tomography.

Patients and methods

A retrospective Institutional Review Board-approved study evaluating 22 patients (26 hips) with severe slipped capital femoral epiphysis (slip angle > 60°) using postoperative three-dimensional computed tomography after in situ pinning was performed. Mean age at slipped capital femoral epiphysis diagnosis was 13 ± 2 years (58% male, four patients bilateral, 23% unstable, 85% chronic). Patients were compared to contralateral asymptomatic hips (15 hips) with unilateral slipped capital femoral epiphysis (control group). Pelvic three-dimensional computed tomography after in situ pinning was used to generate three-dimensional models. Specific software was used to determine range of motion and impingement location (equidistant method). And 22 hips (85%) underwent subsequent surgery.

Results

(1) Severe slipped capital femoral epiphysis patients had significantly (p < 0.001) decreased hip flexion (43 ± 40°) and internal rotation in 90° of flexion (-16 ± 21°, IRF-90°) compared to control group (122 ± 9° and 36 ± 11°). (2) Femoral impingement in maximal flexion was located anterior to anterior-superior (27% on 3 o'clock and 27% on 1 o'clock) of severe slipped capital femoral epiphysis patients and located anterior to anterior-inferior (38% on 3 o'clock and 35% on 4 o'clock) in IRF-90°. (3) However, 21 hips (81%) had flexion < 90° and 22 hips (85%) had < 10° of IRF-90° due to hip impingement and 21 hips (81%) had forced external rotation in 90° of flexion (< 0° of IRF-90°).

Conclusion

After in situ pinning, patient-specific three-dimensional models showed restricted flexion and IRF-90° and forced external rotation in 90° of flexion due to early hip impingement and residual deformity in most of the severe slipped capital femoral epiphysis patients. This could help to plan subsequent hip preservation surgery, such as hip arthroscopy or femoral (derotation) osteotomy.

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).

Do Osteochondroplasty Alone, Intertrochanteric Derotation Osteotomy, and Flexion-Derotation Osteotomy Improve Hip Flexion and Internal Rotation to Normal Range in Hips With Severe SCFE? - A 3D-CT Simulation Study

BACKGROUND

Severe slipped capital femoral epiphysis (SCFE) leads to femoroacetabular impingement and restricted hip motion. We investigated the improvement of impingement-free flexion and internal rotation (IR) in 90 degrees of flexion following a simulated osteochondroplasty, a derotation osteotomy, and a combined flexion-derotation osteotomy in severe SCFE patients using 3D-CT-based collision detection software.

METHODS

Preoperative pelvic CT of 18 untreated patients (21 hips) with severe SCFE (slip-angle>60 degrees) was used to generate patient-specific 3D models. The contralateral hips of the 15 patients with unilateral SCFE served as the control group. There were 14 male hips (mean age 13±2 y). No treatment was performed before CT. Specific collision detection software was used for the calculation of impingement-free flexion and IR in 90 degrees of flexion and simulation of osteochondroplasty, derotation osteotomy, and combined flexion-derotation osteotomy.

RESULTS

Osteochondroplasty alone improved impingement-free motion but compared with the uninvolved contralateral control group, severe SCFE hips had persistently significantly decreased motion (mean flexion 59±32 degrees vs. 122±9 degrees, P <0.001; mean IR in 90 degrees of flexion -5±14 degrees vs. 36±11 degrees, P <0.001). Similarly, the impingement-free motion was improved after derotation osteotomy, and impingement-free flexion after a 30 degrees derotation was equivalent to the control group (113± 42 degrees vs. 122±9 degrees, P =0.052). However, even after the 30 degrees derotation, the impingement-free IR in 90 degrees of flexion persisted lower (13±15 degrees vs. 36±11 degrees, P <0.001). Following the simulation of flexion-derotation osteotomy, mean impingement-free flexion and IR in 90 degrees of flexion increased for combined correction of 20 degrees (20 degrees flexion and 20 degrees derotation) and 30 degrees (30 degrees flexion and 30 degrees derotation). Although mean flexion was equivalent to the control group for both (20 degrees and 30 degrees) combined correction, the mean IR in 90 degrees of flexion persisted decreased, even after the 30 degrees combined flexion-derotation (22±22 degrees vs. 36 degrees±11, P =0.009).

CONCLUSIONS

Simulation of derotation-osteotomy (30 degrees correction) and flexion-derotation-osteotomy (20 degrees correction) normalized hip flexion for severe SCFE patients, but IR in 90 degrees of flexion persisted slightly lower despite significant improvement. Not all SCFE patients had improved hip motion with the performed simulations; therefore, some patients may need a higher degree of correction or combined treatment with osteotomy and cam-resection, although not directly investigated in this study. Patient-specific 3D-models could help individual preoperative planning for severe SCFE patients to normalize the hip motion.

LEVEL OF EVIDENCE

III, case-control study.

Osseoscopy-Assisted Femoral Head Restoration and Vascularized Graft for Slipped Capital Femoral Epiphysis: A Case Report

CASE

A 13-year-old obese adolescent boy with hypothyroidism developed left femoral head avascular necrosis with collapse after slipped capital femoral epiphysis. We restored the femoral head congruity with the aid of osseoscopy and vascularized free fibular graft (VFFG). Four years after surgery, the patient had painless hip range of motion and femoral head contour was maintained.

CONCLUSION

This case highlights a novel use of an arthroscopic camera inside the femoral head to visualize and debride the area of collapse, fill the cavity with cancellous bone graft, and use a VFFG to restore articular support preventing further deterioration of the hip joint.

Tactics of Surgical Treatment of Slipped Capital Femoral Epiphysis Associated With Mild Chronic Epiphyseal Displacement

Background. The appearing of data on cam-type FAI in patients with sequelae of slipped capital femoral epiphysis characterized by mild chronic epiphyseal displacement suggests that along with fixation of the proximal femoral epiphysis, modeling of the head-neck transition and restoration of the femoral offsets using arthroscopic techniques should be performed. Meanwhile, it is well known that after epiphyseal fixation, complete remodeling of the epimetaphysis and, consequently, disappearance of the morphological substrate of potential FAI can occur due to the ongoing enchondral and echondral growth. In this regard, the issue of indications for intraarticular interventions in studied patients remains currently open. The aim of the study was to determine the incidence of FAI in the postoperative period in patients with slipped capital femoral epiphysis characterized by mild chronic epiphyseal displacement, and to estimate the requirement of further surgical treatment. Methods. The results of the examination of 32 patients with mild chronic epiphyseal displacement in the typical posterior inferior direction who underwent cannulated epiphyseal screw fixation were analyzed for the severity of epimetaphysis remodeling and the presence of FAI in the postoperative period. Clinical, radiological, magnetic resonance, and statistical methods were used. Results. At the age of 18-19 years, FAI with pain syndrome in everyday life was found in 9 (28.1%) patients 8 of them did not have even partial remodeling of the femoral component of the joint, another 9 (28.1%) patients did not suffer from pain syndrome in everyday life, but had other clinical, radiological and MR signs of cam-type FAI. Complete or almost complete remodeling of the proximal femoral epimetaphysis occurred in 14 (43.8%) patients. Conclusion. In our opinion, therapeutic and diagnostic arthroscopy of the hip joint for the purpose of modeling the head-neck transition at the age of 18-19 years is indicated for more than one quarter (28.1%) of the investigated patients because of the presence of reliable signs of FAI.

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.

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.

Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg–Calve–Perthes disease

Objective

Correction of post-LCP (Legg–Calve–Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint.

Indications

Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years).

Contraindications

Advanced global osteoarthritis (Tönnis classification ≥ 2).

Surgical technique

By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap.

Postoperative management

Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks.

Results

In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.

Prospective evaluation of in situ screw fixation for stable slipped capital femoral epiphysis

PURPOSE

We aimed to determine which variables were associated with persistent symptoms or need for further surgery in patients treated with in situ fixation for stable slipped capital femoral epiphysis. We hypothesized that patients with greater proximal femoral deformity would require revision surgical intervention.

METHODS

We prospectively collected data on stable slipped capital femoral epiphysis patients who underwent in situ screw fixation at a single institution. Demographic and radiographic information, as well as patient-reported outcomes, were collected.

RESULTS

Forty-six patients (54 hips) with an average follow-up of 3.5 years (range: 2.0-8.5) and mean pre-op Southwick slip angle of 40.5° ± 19.4° were studied. We observed one complication following the index procedure (2%). Twelve hips (22%) went on to have a secondary procedure 2.7 ± 2.2 years after the index surgery. Severe slips were 14.8× more likely to undergo a secondary procedure than mild and moderate slips (p < 0.001). We found no correlation between slip severity and patient-reported outcomes (p > 0.6). Hips requiring a secondary procedure had significantly lower Hip disability and Osteoarthritis Outcome scores (76.8 ± 18.4) at final follow-up compared to hips that did not require additional surgery (86.8 ± 15.7) (p = 0.042).

CONCLUSION

With minimum 2-year follow-up, 22% of patients required a secondary surgery. Patient-reported outcomes did not correlate with slip severity, but were found to be significantly higher in slipped capital femoral epiphysis patients that did not require a secondary procedure. Prophylactic treatment of all slip-related cam deformity was not found to be necessary in this prospective cohort. Patients with moderate-to-severe slips may require secondary surgery.

LEVEL OF EVIDENCE

Level II.

Risk factors for early symptomatic femoroacetabular impingement following in situ fixation of slipped capital femoral epiphysis

In situ fixation of slipped capital femoral epiphysis (SCFE) results in residual deformity that can cause femoroacetabular impingement (FAI). It is unknown what factors could help differentiate patients who are more likely to become symptomatic. We performed a retrospective review of 55 hips treated with in situ pinning for SCFE and subsequent secondary deformity correction procedure for symptomatic FAI and compared them to 39 asymptomatic hips with SCFE deformity using multivariable analysis. Case patients were slightly older than controls (12.6 vs 11.3 years, p = 0.0002) but had similar BMI. The mean epiphyseal-diaphyseal angle was 56° in cases versus 44° in controls (p = 0.0019). Cases were significantly more likely to have obligate external rotation with hip flexion, external foot progression, flexion <90°, antalgic limp, and Trendelenburg lurch. On radiographs, most cases had a head-neck offset ≤0 mm, a distinct metaphyseal corner prominence, acetabular retroversion, and an alpha angle ≥60°. Most controls also had head-neck offset ≤0 mm. Pre-pinning, older age (OR = 1.98 per year, p = 0.0016) and initial epiphyseal-diaphyseal angle (OR = 1.04 per degree, p = 0.018) significantly increased the odds of having symptomatic FAI. Post-pinning, external foot progression increased the odds of symptomatic FAI by 10.48 (p = 0.017), and an alpha angle ≥60° resulted in 11.4 times higher odds of symptomatic FAI (p = 0.011). The linear correlation between epiphyseal-diaphyseal and alpha angle was poor (r = 0.28). Older age and initial epiphyseal-diaphyseal pre-pinning mildly increased the odds of eventual symptomatic FAI. This information can help the surgeon to predict which patients may develop symptomatic FAI.

The modified Dunn procedure can be performed safely in stable slipped capital femoral epiphysis but does not alter avascular necrosis rates in unstable cases: a large single-centre cohort study

PURPOSE

The modified Dunn procedure for slipped capital femoral epiphysis (SCFE) remains controversial. We reviewed our series over ten years to report our learning curve, experience with intraoperative monitoring of femoral head perfusion and its correlation with postoperative Single-photon emission computed tomography (SPECT-CT) bone scan and femoral head collapse in stable and unstable SCFE.

METHODS

We retrospectively assessed 217 consecutive modified Dunn procedures performed between 2008 and 2018. In all, 178 had a minimum of one-year follow-up (mean 2.7 years (1 to 9.2)) including 107 stable and 71 unstable SCFE. Postoperative viability was assessed with a three-phase Tc99 bone scan and SPECT-CT. From 2011, femoral head perfusion monitoring was performed intraoperatively using a Codman Intracranial Pressure transducer and the capsulotomy was modified.

RESULTS

With intraoperative monitoring, the rate of non-viable femoral heads in stable SCFE decreased from 21.1% to 0% (p < 0.001). In unstable SCFE, the rate remained unchanged from 35.7% to 29.8% (p = 0.669). The positive predictive value (PPV) of pulsatile monitoring for no collapse was 100% in stable and 89.1% in unstable SCFE. Pulsatile monitoring and viable SPECT-CT bone scan gave a 100% PPV for all cases. A non-viable scan defines those hips at risk of collapse since 100% of stable and 68.2% of unstable hips with non-viable bone scans went on to collapse.

CONCLUSION

Our protocol enables safe performance of this complex procedure in stable SCFE with intraoperative monitoring being a reliable asset. The avascular necrosis rate for unstable SCFE remained unchanged and further research into its best management is required.

LEVEL OF EVIDENCE

Level III.

Patients With Symptomatic Sequelae of Slipped Capital Femoral Epiphysis Have Advanced Cartilage Wear at the Time of Surgical Intervention

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is a common hip problem in children. The resulting deformity can cause impingement similar to cam-type idiopathic femoroacetabular impingement (FAI). Although there are similarities between FAI and SCFE, deformity patterns, severity, and time of onset of symptoms varies, which may impact management. The purpose of this study was to describe patterns of articular cartilage damage in patients undergoing surgical hip dislocation for sequelae of SCFE in comparison to patients undergoing arthroscopic surgery for primary FAI.

METHODS

Patients were identified who underwent surgical treatment for hip pain due to primary FAI (cam type) or sequelae of SCFE. Clinical data and radiographic measurements were recorded. Cartilage was assessed intraoperatively. Severity was classified using the modified Beck classification, while location was classified into 6 sectors. Statistical analysis was performed to test for differences in demographic and radiographic characteristics between the SCFE and FAI patients. χ2 or Fisher exact tests were used to evaluate trends in patterns of acetabular and femoral cartilage wear between SCFE and FAI groups.

RESULTS

The SCFE group had 28 hips compared with 304 in the FAI group. SCFE patients were younger (19 vs. 32, P<0.001), had higher body mass index (30±5.9 vs. 24±4.8, P<0.001), and were more often male (61% vs. 27%, P<0.001). Deformity severity based on α-angle was higher in the SCFE group [AP 74 vs. 55 (P=0.001) and Dunn 72 vs. 58 (P<0.001)]. There were no significant differences with regards to lateral center edge angle, anterior center edge angle, or Tonnis angle. In both groups the most common locations for cartilage lesions in both groups were the anterior peripheral and superolateral peripheral regions with fewer but more widely distributed femoral head lesions. The SCFE group had higher rates of femoral head and superolateral central cartilage lesions compared with the FAI group. There was no statistical difference between high-grade femoral or acetabular cartilage lesions between groups.

CONCLUSIONS

Patients with SCFE were younger at the time of surgery and presented with more severe deformity based on radiographic α-angle compared to patients with FAI. Our results suggest higher prevalence of femoral head lesions and more diffuse cartilage injury in patients with SCFE. This study can be used to support early surgical intervention in patients with symptomatic sequelae of SCFE due to risk of premature joint damage.

LEVEL OF EVIDENCE

Level III-prognostic study.

Does a History of Slipped Capital Femoral Epiphysis in Patients Undergoing Femoroacetabular Osteoplasty for Femoroacetabular Impingement Affect Outcomes Scores or Risk of Reoperation?

BACKGROUND

Femoroacetabular impingement (FAI) can occur after slipped capital femoral epiphysis (SCFE) regardless of slip severity and even after in situ pinning. These patients represent a rare and unique demographic that is largely unreported on. It is important to further characterize the clinical presentation of these patients, associated treatment modalities, and the efficacy of these treatment modalities.

QUESTIONS/PURPOSES

(1) How do patients with post-SCFE FAI typically present in terms of radiographic and surgical findings? (2) How do their hip-specific and general-health outcomes scores after mini-open femoroacetabular osteoplasty compare with those obtained in a matched group of patients with FAI caused by other etiologies? (3) How do those groups compare in terms of the proportion who undergo conversion to THA?

METHODS

Between 2013 and 2017, 20 patients had femoroacetabular osteoplasty for post-SCFE FAI. During that time, general indications for this procedure were symptomatic FAI demonstrated on radiographs and physical exam. Of those, none was lost to follow-up before a minimum of 2 years, leaving all 20 available for matching, and all 20 had suitable matches in our database for patients who underwent femoroacetabular osteoplasty for other diagnoses. Matching was performed by surgeon, patient age, patient gender, and BMI. The matching group was drawn from a large database of patients who had the same procedure during the same period. We matched in a 1:3 ratio to arrive at 60 randomly selected control patients in this retrospective, comparative study. Patient demographics, medical history, clinical presentation, radiographic parameters, and intraoperative findings were compared between the two groups. At a minimum of 2 years of follow-up, the latest clinical functional outcome scores (Hip Disability and Osteoarthritis Outcome Score Jr and SF-12) and proportions of conversion to THA were compared between the groups.

RESULTS

A greater percentage of patients with a history of SCFE than those without prior SCFE demonstrated full chondral lesions intraoperatively (90% [18 of 20] versus 32% [19 of 60], odds ratio 7 [95% confidence interval 1 to 178]; p < 0.01). A greater percentage of patients with a history of SCFE also demonstrated labral calcifications intraoperatively compared with those without prior SCFE (65% [13 of 20] versus 35% [21 of 60], OR 3 [95% CI 1 to 10]; p = 0.04). Radiographically, patients with SCFE had greater preoperative alpha angles than did patients without SCFE (94° ± 13° versus 72° ± 22°; p = 0.01) as well as lower lateral center-edge angles (25° ± 8° versus 31° ± 8°; p = 0.04). There was no difference in postoperative follow-up between patients with a history of SCFE and patients without a history of SCFE (4 ± 2 years versus 4 ± 2 years; p = 0.32). There was no difference in the mean postoperative outcome scores between patients with a history of SCFE and patients without (Hip Disability and Osteoarthritis Outcome Score Jr: 75 ± 28 points versus 74 ± 17 points; p = 0.95; SF-12 physical score: 40 ± 11 points versus 39 ± 8 points; p = 0.79). There was no difference with the numbers available in the percentage of patients who underwent conversion to THA (15% [3 of 20] versus 12% [7 of 60], OR 1.36 [95% CI 0 to 6]; p = 0.71).

CONCLUSION

Patients with FAI after SCFE present with a greater degree of labral and chondral disease than do patients without a history of SCFE. However, at short-term follow-up, the proportion of patients who underwent conversion to THA and patients' postoperative outcome scores did not differ in this small, comparative series between patients with and without SCFE. Further evaluation with long-term follow-up is needed, especially given the more severe chondral damage we observed in patients with SCFE at the time of surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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.

Femoral neck osteotomy in skeletally mature patients: surgical technique and midterm results

PURPOSE

Using an extended retinacular flap containing the blood supply for the femoral head, proximal femur osteotomies can be performed at the neck level increasing the potential of correction of complex morphologies. The aim of this study was to analyze the safety, clinical, and radiographic results of this intra-articular surgical technique performed in skeletally mature patients with a minimum follow-up of three years.

METHODS

Fourteen symptomatic adult patients (16 hips) with a mean age of 26 years underwent FNO using surgical hip dislocation and an extended soft tissue flap. Radiographs and radial magnetic resonance imaging (MRI) were obtained before and after surgery to evaluate articular congruency, cartilage damage, and morphologic parameters. Clinical functional evaluation was done using the Nonarthritic Hip Score (NAHS), the Hip Outcome Score (HOS), and the modified Harris Hip Score (mHHS).

RESULTS

After surgery, no avascular necrosis was observed, and all the osteotomies healed without complication. The initial neck/shaft angle (range 120 to 150°) improved in all cases to a mean value of 130° ± 4.6 (p < 0.001). In eight of nine valgus hips, the high-positioned fovea capitis changed to a normal position after surgery. The NAHS score improved from a mean of 36.5 ± 14.9 to 82.9 ± 13.9 points after surgery (p < 0.001). After surgery, the mean HOS was 87.1 ± 17.6 points, and the mean mHHS was 78.6 ± 17 points.

CONCLUSIONS

In this series, femoral neck osteotomy in the adult, although technically more demanding compared with other classic osteotomies, can be considered a safe procedure with considerable potential to correct hip deformities.

Combined Imhauser osteotomy and osteochondroplasty in slipped capital femoral epiphysis through surgical hip dislocation approach

PURPOSE

Treatment of moderate to severe stable slipped capital femoral epiphysis (SCFE) remains a challenging problem. Open reduction by modified Dunn procedure carries a considerable risk of osteonecrosis (ON). Imhauser osteotomy is capable of realigning the deformity without the risk of ON, but the remaining metaphyseal bump is implicated with significant chondro-labral lesions and accelerated osteoarthritis. We conducted this study to evaluate the efficacy and safety of Imhauser osteotomy combined with osteochondroplasty (OCP) through the surgical hip dislocation (SHD) approach.

METHODS

A prospective series of 23 patients with moderate-severe stable SCFE underwent Imhauser osteotomy and OCP through SHD. The mean age was 14.4 years (13 to 20) and the mean follow-up period was 45 months (24 to 66). The outcome measures included clinical and radiological parameters and Harris hip score (HHS) was used as a functional score.

RESULTS

The mean HHS improved significantly from 65.39 to 93.3. The limb length discrepancy improved by a mean of 1.72 cm. The mean flexion and abduction arcs showed a significant improvement (mean increase of 37.5° and 18.5°, respectively). The mean internal rotation demonstrated the most significant improvement (mean increase of 38.5°). All the radiographic parameters improved significantly; including anterior and lateral slip angles (mean improvement 37.52° and 44.37°, respectively). The mean alpha angle decreased by 39.19°. The articulo-trochanteric distance significantly increased to a mean of 23.26 mm. No cases of ON or chondrolysis were identified.

CONCLUSION

Combined Imhauser osteotomy and OCP through the surgical dislocation approach provide a comprehensive and safe management of moderate to severe stable SCFE.

LEVEL OF EVIDENCE

IV.

Long-term hip function in slipped capital femoral epiphysis treated with in situ pinning

BACKGROUND

In recent years, there has been a trend toward more aggressive management of slipped capital femoral epiphysis (SCFE) with acute anatomical realignment; however, the literature is unclear with regard to the indications for this.

QUESTIONS/PURPOSES

To collect long-term patient-reported outcome scores on a group of SCFE patients using modern hip scores. The second aim was to determine whether there is a threshold level of deformity beyond which patients have predictably poor outcomes following in situ pinning.

PATIENTS AND METHODS

Patients presenting with SCFE between 2000 and 2009 completed a survey consisting of three modern hip scores and were classified into poor, intermediate, and good outcome groups. The posterior slope angle (PSA) was used to measure slip deformity. We examined the relationship between patient characteristics and functional outcomes. The relationship between PSA score and overall outcome was examined using receiver operator curve (ROC) analysis.

RESULTS

The total study population was 63; 14% patients had poor, 29% had intermediate, and 57% had good functional outcomes. The mean Non-Arthritic Hip Scores (NAHSs) for those with poor outcomes was 51, 76 in the intermediate group, and 95 in the good group ( p <0.001). PSA was significantly lower in those with good functional outcomes. ROC analysis demonstrated that a higher PSA was moderately predictive of a poor clinical outcome (area under the curve of 0.668). In both the poor and intermediate outcome groups, 50% of patients had a PSA of 40° or greater, whereas only 31% of those with good clinical outcomes had PSA of 40° or greater.

CONCLUSIONS

A significant proportion of post-SCFE patients have ongoing suboptimal hip function after pinning in situ. Those with a PSA more than 40° have a higher chance of a poor outcome.

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.

Treatment for Post-Slipped Capital Femoral Epiphysis Deformity

In situ pinning of slipped capital femoral epiphysis (SCFE) is a safe and effective treatment modality, but often results in residual deformity leading to femoroacetabular impingement, which may limit patient activities and predispose to early onset arthritis. Enhanced understanding of the implications of femoroacetabular impingement and new surgical techniques have prompted interest in treating post-slipped capital femoral epiphysis deformity to both improve current symptoms and delay or prevent hip arthrosis.

[The modified Dunn procedure to treat severe slipped capital femoral epiphysis]

The modified Dunn procedure enables restoration of the proximal femoral anatomy and normal hip function in patients with slipped capital femoral epiphysis (SCFE). Surgery is indicated in severe SCFE and in hips with a moderate slip angle and impaired function. To prevent further dislocation of the femoral head, the authors recommend non-weightbearing until surgery, since an accurate evaluation of slip stability is not possible in the clinical setting. Only a well-trained orthopedic surgeon with a high level of expertise in hip preservation surgery should perform this procedure. Precise knowledge of the vascular anatomy of the proximal femur is essential to perform successful surgery with low rates of complications such as avascular necrosis of the femoral head. Surgical hip dislocation with osteotomy of the greater trochanter is the approach used. After arthrotomy, stability of the physis is checked. To prevent rupture of the retinacular vessels in hips with an unstable physis, these heads are prophylactically pinned before dislocation out of the socket. Blood supply to the femoral head as well as intraarticular damage can be judged in the dislocated position of the femoral head. The retinacular flap preserves epiphyseal perfusion while the femoral head is dislocated from the femoral neck. Resection of posteromedial callous formation from the femoral neck as well as removal of the remaining physis from the femoral head prevent stress on the retinacular vessels after reduction of the femoral head (epiphysis) on the neck.

Findings and Management of the Rare Caput Flexum Deformity of the Hip: A Case Report

CASE

A 10-year-old girl presented after possible occult hip trauma, with shortening of the leg being the initial clinical symptom, followed by motion-dependent pain. She had limited external rotation in extension with anterior apprehension. Radiographically, the deformity was an anterior tilt of the epiphysis with coxa vara. Surgery included surgical dislocation using a retinacular flap for the anterior open wedge femoral neck osteotomy for extension and posterior translation, with an excellent 4.5-year clinical outcome.

CONCLUSIONS

Caput flexum is a rare deformity with localized premature closure of the anterior growth plate of the hip. To avoid secondary impingement, an osteotomy was successfully placed close to the deformity.

Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis

PURPOSE OF REVIEW

To review slipped capital femoral epiphysis (SCFE), with a focus on new insights into its etiology and evolving methods of operative fixation.

RECENT FINDINGS

The epiphyseal tubercle and its size during adolescence are paramount to understanding the mechanism of SCFE. In chronic stable SCFE, the epiphysis rotates about the tubercle protecting the lateral epiphyseal vessels from disruption. In an acute unstable SCFE, the tubercle displaces, increasing the risk of osteonecrosis, also known as avascular necrosis (AVN). Intraoperative stability suggests that stable and unstable SCFE based on ambulation may be inaccurate. For stable SCFE, in situ pinning remains the most accepted treatment for mild slips with delayed symptomatic femoroacetabular impingement (FAI) management. Treatment of moderate to severe stable slips with realignment osteotomy leads to less femoral deformity and potentially better outcomes. However, it has a higher risk of complications, including AVN and chondrolysis. Our knowledge of the etiology for SCFE is evolving. The optimal technique for operative treatment of moderate to severe SCFE is controversial and varies by center. Well-controlled studies of these patients are needed to understand the best treatment for this difficult problem. Furthermore, increasing the awareness about SCFE is paramount to allow for early recognition and treatment of deformity at its early stages and avoiding severe SCFE deformity which has been associated with worse long-term outcomes.

Subcapital Shortening Osteotomy for Severe Slipped Capital Femoral Epiphysis: Preliminary Results of the French Multicenter Study

BACKGROUND

There is growing evidence that symptomatic femoroacetabular impingement (FAI) can develop after severe slipped capital femoral epiphysis (SCFE) fixed in situ. Realignment procedures have therefore gained popularity, but complication rates remain controversial. Among them, the subcapital shortening osteotomy without hip dislocation has been progressively adopted in France, but results have never been assessed to date.

METHODS

All cases performed in 23 French university hospitals between January 2010 and March 2014 were reviewed to (1) describe the surgical procedure, (2) assess the radiologic and functional outcomes, and (3) report complications and more specifically the avascular necrosis rate (AVN) according to initial stability. Stable and unstable SCFE were distinguished following Loder's definition. Radiologic outcomes were assessed by the 3 authors to determine FAI and osteonecrosis rates. Functional outcomes were evaluated at follow-up and complications were reported.

RESULTS

A total of 82 cases (45 unstable and 37 stable), performed in 10 institutions, were included with a mean follow-up of 25 months. No intraoperative complication occurred but 2 patients (2.4%) underwent unplanned early revision. Slip angle was significantly reduced (87%) without loss of correction. Overall AVN rate was 9.7%, reaching 13.3% in unstable slips. However, preoperative magnetic resonance imaging showed that most of the unstable epiphyses (4/6) were already hypoperfused before surgery.

CONCLUSIONS

The procedure is a reliable option for the treatment of severe SCFE. AVN rates are lower than previously reported in multicenter series of modified Dunn technique, especially in unstable slips. However, the risk of AVN in severe stable SCFE (5.4%) must still be balanced with the functional outcomes of potential future FAI.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Use of near-infrared systems for investigations of hemodynamics in human in vivo bone tissue: A systematic review

A range of technologies using near infrared (NIR) light have shown promise at providing real time measurements of hemodynamic markers in bone tissue in vivo, an exciting prospect given existing difficulties in measuring hemodynamics in bone tissue. This systematic review aimed to evaluate the evidence for this potential use of NIR systems, establishing their potential as a research tool in this field. Major electronic databases including MEDLINE and EMBASE were searched using pre-planned search strategies with broad scope for any in vivo use of NIR technologies in human bone tissue. Following identification of studies by title and abstract screening, full text inclusion was determined by double blind assessment using predefined criteria. Full text studies for inclusion were data extracted using a predesigned proforma and quality assessed. Narrative synthesis was appropriate given the wide heterogeneity of included studies. Eighty-eight full text studies fulfilled the inclusion criteria, 57 addressing laser Doppler flowmetry (56 intra-operatively), 21 near infrared spectroscopy, and 10 photoplethysmography. The heterogeneity of the methodologies included differing hemodynamic markers, measurement protocols, anatomical locations, and research applications, making meaningful direct comparisons impossible. Further, studies were often limited by small sample sizes with potential selection biases, detection biases, and wide variability in results between participants. Despite promising potential in the use of NIR light to interrogate bone circulation, the application of NIR systems in bone requires rigorous assessment of the reproducibility of potential hemodynamic markers and further validation of these markers against alternative physiologically relevant reference standards. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2595-2603, 2018.

Comparison between modified Dunn procedure and in situ fixation for severe stable slipped capital femoral epiphysis

Background and purpose - The best treatment option for severe slipped capital femoral epiphysis (SCFE) is still controversial. We compared clinical and radiographic outcomes of modified Dunn procedure (D) and in situ fixation (S) in severe SCFE. Patients and methods - We retrospectively compared D and S, used for severe stable SCFE (posterior sloping angle (PSA) > 50°) in 29 patients (15 D; 14 S). Propensity analysis and inverse probability of treatment weights (IPTW) to adjust for baseline differences were performed. Patients were followed for 2-7 years. Results - Avascular necrosis (AVN) occurred in 3 patients out of 15, after D, causing conversion to total hip replacement (THR) in 2 cases. In S, 1 hip developed chondrolysis, requiring THR 3 years after surgery. 3 symptomatic femoroacetabular impingements (FAI) occurred after S, requiring corrective osteotomy in 1 hip, and osteochondroplasty in another case. The risk of early re-operation was similar between the groups. The slippage was corrected more accurately and reliably by D. The Nonarthritic Hip Score was similar between groups, after adjusting for preoperative and postoperative variables. Interpretation - Although D was superior to S in restoring the proximal femoral anatomy, without increasing the risk of early re-operation, some concern remains regarding the potential risk of AVN in group D.

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.

Valgus Slipped Capital Femoral Epiphysis: Pathophysiology of Motion and Results of Intracapsular Realignment

OBJECTIVES

The purpose of this study was to report (1) a different but specific pattern of impingement in hips involved with valgus slipped capital femoral epiphysis (valgus SCFE) and (2) the results of surgical treatment using intracapsular realignment techniques.

DESIGN

Case series.

SETTING

Multiple academic centers.

PATIENTS

Six patients with 8 involved hips referred for valgus alignment of proximal femoral epiphysis (valgus SCFE).

INTERVENTION

Intracapsular realignment osteotomy combined with periacetabular osteotomy if needed.

MAIN OUTCOME MEASUREMENT

The clinical and radiographical results and pathophysiology of motion.

RESULTS

Eight hips in 6 patients were treated with subcapital (5 hips) or femoral neck (3 hips) osteotomy for realignment. The medially prominent metaphysis created an inclusive impingement at the anterior acetabular wall, whereas the high coxa valga favored impacting impingement at the posterior head-neck junction. The mean preoperative epiphyseal-shaft angle of 110.5 (range 90-125 degrees) was reduced to 62 degrees (range 55-70 degrees) postoperatively. At the last follow-up, all but 1 hip were pain-free and impingement-free, with normal range of motion. One hip was replaced after repeated attempts of correction. The overall hip functional result using modified Merle d'Aubigne scoring system was excellent in 5 hips (18-16 points), good in 2 hips (16-15 points), and poor in 1 hip (6 points).

CONCLUSIONS

Impingement in valgus SCFE deformity is specific and complex. Anatomical realignment can lead to favorable results by the restoration of normal morphology and impingement-free range of motion.

LEVEL OF EVIDENCE

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

Surgical treatment of femoroacetabular impingement following slipped capital femoral epiphysis: A systematic review

Objectives

The purpose of this study was to evaluate the existing literature from 2005 to 2016 reporting on the efficacy of surgical management of patients with femoroacetabular impingement (FAI) secondary to slipped capital femoral epiphysis (SCFE).

Methods

The electronic databases MEDLINE, EMBASE, and PubMed were searched and screened in duplicate. Data such as patient demographics, surgical technique, surgical outcomes and complications were retrieved from eligible studies.

Results

Fifteen eligible level IV studies were included in this review comprising 261 patients (266 hips). Treatment groups included arthroscopic osteochondroplasty, surgical hip dislocation, and traditional open osteotomy. The mean alpha angle corrections were 32.14° (standard deviation (sd) 7.02°), 41.45° (sd 10.5°) and 6.0° (sd 5.21°), for arthroscopy, surgical hip dislocation, and open osteotomy groups, respectively (p < 0.05). Each group demonstrated satisfactory clinical outcomes across their respective scoring systems. Major complication rates were 1.6%, 10.7%, and 6.7%, for arthroscopy, surgical dislocation and osteotomy treatments, respectively.

Conclusion

In the context of SCFE-related FAI, surgical hip dislocation demonstrated improved correction of the alpha angle, albeit at higher complication and revision rates than both arthroscopic and open osteotomy treatments. Further investigation, including high-quality trials with standardised radiological and clinical outcome measures for young patients, is warranted to clarify treatment approaches and safety.

Cite this article: K. O. Oduwole, D. de Sa, J. Kay, F. Findakli, A. Duong, N. Simunovic, Y. Yi-Meng, O. R. Ayeni. Surgical treatment of femoroacetabular impingement following slipped capital femoral epiphysis: A systematic review. Bone Joint Res 2017;6:472–480. DOI: 10.1302/2046-3758.68.BJR-2017-0018.R1.

Arterial Topographic Anatomy Near the Femoral Head-Neck Perforation with Surgical Relevance

BACKGROUND

Knowledge of the vascular supply of the femoral head is crucial for hip-preserving surgical procedures. The critical area for reshaping cam deformity is at the retinacular vessel penetration, an area with ill-defined topographic anatomy. We performed a cadaver study of the extension of the lateral retinaculum near the head-neck junction, distribution of the arterial vascular foramina, and initial intracapital course of these vessels.

METHODS

In 16 fresh proximal parts of the femur without head-neck deformities, the deep branch of the medial femoral circumflex artery was injected with gadolinium for magnetic resonance imaging (MRI) sequences to identify arterial structures.

RESULTS

We found a mean number of 4.5 arterial foramina, showing a predominance from 10 to 12 o'clock. The retinaculum extended 20 mm from 1 to 10 o'clock. The surface distance from the cartilage border to the vascular foramina under the synovial fold was 6.5 mm, and the depth from the same cartilage border to the initial intraosseous vessel pathways was 5.3 mm.

CONCLUSIONS

The data add further precision to the arterial topography at the retinacular foramina, an area that is crucial for the perfusion of the femoral head. It may overlap with the area of anterolateral cam deformity and plays a role in choosing the cuts for subcapital and intracapital osteotomies.

CLINICAL RELEVANCE

The information is taken from normal hips and may not be directly applicable to the deformed hip. Nevertheless, it is a prerequisite for a surgeon to understand the normal anatomy and use those boundaries to prevent mistakes during intra-articular joint-preserving hip surgical procedures.

Slipped capital femoral epiphysis: a review of management in the hip impingement era

Slipped capital femoral epiphysis (SCFE) remains the most common adolescent hip disorder. Most cases present with stable slips, and in situ fixation is the most commonly adopted treatment worldwide. The introduction of the concept of femoroacetabular impingement and subsequent studies have revealed SCFE-related hip impingement to be a significant pre-arthritic condition, and the previously suggested remodeling of the proximal femur after in situ fixation has been called into question. Complex proximal femoral osteotomies and more recently intra-articular procedures via surgical hip dislocation have been employed. The literature is still lacking a strong evidence to undertake such aggressive procedures. Moreover, the application of a particular procedure regarding the nature of the slip, being stable or unstable, the degree of the slip, and the condition of the physis has not been extensively described in the literature. The purpose of this article is to outline the SCFE-related hip impingement, to review the best evidence for the current treatment options for both stable and unstable slips, and to develop an algorithm for decision making.

Femoral and acetabular re-alignment in slipped capital femoral epiphysis

NEW PATHOPHYSIOLOGICAL INSIGHTS

Based on improved knowledge of the vascular supply of the proximal femur, a safe surgical dislocation of the hip joint was established allowing direct insights to the pathomorphological malfunctioning of the joint. One insight was that slipped capital femoral epiphysis (SCFE) impingement leads to substantial damage of the chondrolabral rim area, even in the presence of minor slips. A further surgical development was the extended retinacular flap allowing for correction of the deformity with calculable risk for iatrogenic necrosis.

CONSECUTIVE SURGICAL CONCEPT

In 20 years of experience, a treatment concept for SCFE could be established which replaces classic pinning in situ and indirect correction of the deformity with subcapital re-alignment when the physis is still open, with true femoral neck osteotomy for hips with closed physis. Pinning in situ still has a place in minor slips but should be combined with open or arthroscopic recreation of an anterior metaphyseal waisting.

UNEXPECTED COMPLICATION

Loss of joint stability is a rare complication of anatomic re-alignment. It can be disease-related when the impingement has induced severe destruction of acetabular cartilage. It can be related to the surgical procedure, especially when the neck was excessively shortened and refixation of the trochanter was not advanced. Finally, in cases with severe and long-lasting deformity, the acetabulum may undergo adaptive flattening, being the cause of joint destabilisation with the correction of the deformity. Advancement of the greater trochanter and/or peri-acetabular osteotomy may be discussed to restabilise the joint.

The modified Dunn procedure for slipped capital femoral epiphysis: the Bernese experience

PURPOSE

Based on previous investigations on the vascular blood supply to the femoral head, a technique for anatomical reduction after slipped capital femoral epiphysis was developed. This technique is a modification of the original technique by Dunn using a retinacular soft-tissue flap. This allows the visual control of the epiphyseal vascular blood supply. We report the experience at the inventor's institution with a critical discussion of the available literature.

METHODS

Using a trochanteric osteotomy for surgical dislocation of the hip, a retinacular soft tissue flap is created containing the deep branch of the medial femoral circumflex artery, the external rotators and the capsule. The femoral epiphysis can be mobilised safely and reduced on the femoral neck after resection of the almost constantly present reactive metaphyseal callus.

RESULTS

In our institution, the rate of avascular necrosis with 2% is comparably low to Dunn's original results. It is only present in cases where no bleeding was already evident before reduction of the epiphysis. The ten-year long-term results are favorable in these cases with a good functional result and only little progression of osteoarthritis. However, other authors have reported higher rates of avascular necrosis up to 24% in their initial experience.

CONCLUSIONS

In experienced hands using the correct meticulous surgical technique, the results are favorable regarding the rates of avascular necrosis, the functional outcome and the development of radiographic osteoarthritis - even in acute and severe cases. Avascular necrosis is rare but can be observed if there is no evidence of intra-operative femoral head perfusion before and after reduction of the epiphysis.

Instability of the hip after anatomical re-alignment in patients with a slipped capital femoral epiphysis

AIMS

Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases.

MATERIALS AND METHODS

We explored the literature on the possible pathophysiological causes and surgical steps associated with the risk of post-operative instability and articular damage. In addition, we describe supplementary steps that could be used to avoid these problems.

RESULTS

The causes of instability may be divided into three main groups: the first includes causes directly related to SCFE (acetabular labral damage, severe abrasion of the acetabular cartilage, flattening of the acetabular roof and a bell-shaped deformity of the epiphysis); the second, causes not related to the SCFE (acetabular orientation and poor quality of the soft tissues); the third, causes directly related to the surgery (capsulotomy, division of the ligamentum teres, shortening of the femoral neck, pelvi-trochanteric impingement, previous proximal femoral osteotomy and post-operative positioning of the leg).

CONCLUSION

We present examples drawn from our clinical practice, as well as possible ways of reducing the risks of these complications, and of correcting them if they happen. Cite this article: Bone Joint J 2017;99-B:16-21.

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.

Joint Instability After Anatomic Reconstruction of Severe, Chronic Slipped Capital Femoral Epiphysis: A Report of 3 Cases, with High Femoral Anteversion in 1 and Adaptive Acetabular Roof Deformation in 3

CASES

Joint instability after slipped capital femoral epiphysis (SCFE) reorientation through the physis has been attributed to a combination of capsulotomy and chondrolabral rim damage. We report on 3 hips with severe SCFE with closed physes, in which anatomic correction with femoral neck osteotomy led to joint instability. All 3 had acetabular roof flattening; 1 showed slight additional acetabular retroversion but also increased femoral anteversion.

CONCLUSION

We speculate that the slight roof flattening in all 3 cases and/or the high femoral anteversion in 1 case had contributed to joint instability. Femoral derotation osteotomy was performed in 1 and periacetabular osteotomy was performed in 2 for joint restabilization.

Modified Dunn osteotomy using an anterior approach used to treat 26 cases of SCFE

INTRODUCTION

Osteotomy performed below the femoral neck plays a leading role in the treatment of slipped capital femoral epiphysis (SCFE). It results in anatomical reduction. Several modifications have been made to Dunn's original osteotomy technique. We have developed another modification to this technique that uses an anterior surgical approach on a traction table with fluoroscopy control.

HYPOTHESES

Will this technique help to reduce the number of complications? Will its results be superior to those achieved with the standard Dunn osteotomy procedure?

MATERIAL AND METHODS

This was a retrospective single-center study of 26 cases in 24 patients (2 bilateral cases). Patients were positioned supine on a traction table with fluoroscopy control. An anterior surgical approach was used. A trapezoid-shaped osteotomy was performed below the femoral head. The head's reduction was checked on the fluoroscope and the fixation confirmed. The Postel Merle d'Aubigné (PMA) score was used for the clinical assessment. The radiographic assessment was based on Southwick's angle.

RESULTS

The mean slip angle of the femoral head was 57°. A mean correction of 47° was achieved. Based on the PMA score, good and excellent results were achieved in 20 cases (77%) and poor results occurred in 6 cases (23%). The surgical treatment had a significant effect on the PMA score (P=0.0008). In terms of complications, there were five cases of chondrolysis and one case of necrosis associated with chondrolysis.

DISCUSSION

The anterior approach provides direct access to the femoral neck, and thereby a cautious osteotomy at the site of the slip itself. Use of a traction table makes the external manipulations, reduction and fixation procedures easier to carry out. The results of this study were comparable to published results.

LEVEL OF PROOF

IV, retrospective treatment study.

Femoroacetabular impingement in children and adolescents

PURPOSE OF REVIEW

The present review discusses the etiology, clinical presentation, and management of femoroacetabular impingement (FAI) in the pediatric population, including etiologic and diagnostic controversies, management options, and outcomes.

RECENT FINDINGS

New evidence demonstrates conflicting results regarding how and when primary FAI develops in relation to skeletal maturity. Recent studies also discuss the effects of sex, race, and sports on FAI development and radiographic considerations in the pediatric population. Recent literature demonstrates good to excellent outcomes in the operative management of FAI in children and adolescents.

SUMMARY

FAI is a source of pediatric hip pain and can occur primarily or secondarily. It is characterized by anterior hip pain, made worse with flexion activities, decreased hip internal rotation, and a positive impingement sign. Pathologic values for radiographic measures of FAI are not clearly defined in the pediatric population. As FAI is a risk factor for osteoarthritis, early intervention in specific patients may be indicated. Hip arthroscopy, surgical hip dislocation, or combined mini-open and arthroscopic approaches are utilized, with good to excellent short, and mid-term functional results. Further study is required in the pediatric population to identify potential preventive strategies, to delineate the pathologic radiographic values of FAI, to define specific indications for operative management, and to examine long-term outcomes to determine optimal management.

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.

Modified Dunn Procedure is Superior to In Situ Pinning for Short-term Clinical and Radiographic Improvement in Severe Stable SCFE

BACKGROUND

In situ pinning is the conventional treatment for a stable slipped capital femoral epiphysis (SCFE). However, with a severe stable SCFE the residual deformity may lead to femoroacetabular impingement and articular cartilage damage. A modified Dunn subcapital realignment procedure has been developed to allow for correction at the level of the deformity while preserving the blood supply to the femoral head.

QUESTIONS/PURPOSES

We compared children with severe stable SCFE treated with the modified Dunn procedure or in situ pinning in terms of (1) proximal femoral radiographic deformity; (2) Heyman and Herndon clinical outcome; (3) complication rate; and (4) number of reoperations performed after the initial procedure.

METHODS

In this nonmatched retrospective study, 15 patients treated with the modified Dunn procedure (between 2007 and 2012) and 15 treated with in situ pinning (between 2001 and 2009) for severe but stable SCFE were followed for a mean of 2.5 years (range, 1-6 years). During the period in question, the decision regarding which procedure to use was based on the on-call surgeon's discretion; six surgeons performed in situ pinning and three surgeons performed the modified Dunn procedure. A total of 15 other patients were treated for the same diagnosis during the study period but were lost to followup before 1 year; of those, 12 were in the in situ pinning group. Radiographs were reviewed to measure the AP and lateral alpha angles, femoral head-neck offset, and Southwick angle preoperatively and at the latest clinical visit. The Heyman and Herndon clinical outcome, complications, and subsequent hip surgeries were recorded.

RESULTS

At latest followup, the median AP alpha angle (52°, range 41°-59° versus 76°, interquartile range [IQR]: 68°-88°; p = 0.0017), median lateral alpha angle (44°, IQR: 40°-51° versus 87°, IQR: 74°-96°; p < 0.001), median head-neck offset (7 mm, IQR: 5-9 mm versus -5, IQR: -11 to -4 mm; p < 0.001), and median Southwick angle (16°, IQR: 6°-23° versus 58°, IQR: 47°-66°; p < 0.001) revealed better deformity correction with the modified Dunn procedure compared with in situ pinning. Nine patients had good or excellent results in the modified Dunn group compared with four of 15 in the in situ pinning group (p = 0.0343; odds ratio, 5.86; 95% CI, 1.13-40.43). With the numbers available, there were no differences in the numbers of complications in each group (five versus three complications in the in situ and modified Dunn groups, respectively; p = 0.66), but there were more reoperations in the in situ pinning group (three versus seven; p = 0.0230).

CONCLUSIONS

The modified Dunn procedure results in better morphologic features of the femur, a higher rate of good and excellent Heyman and Herndon clinical outcome, a lower reoperation rate, and a similar occurrence of complications when compared with in situ pinning for treatment of severe stable SCFE.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Development of Bilateral Cam Deformity After Dunn Procedure and Contralateral Prophylactic Fixation: A Periosteal Reaction?: A Case Report

CASE

We present the case of a fourteen-year-old male athlete with a slipped capital femoral epiphysis who was managed with a unilateral Dunn procedure and contralateral prophylactic screw fixation. Even though the cartilaginous epiphyseal growth plate was removed on one side, cam deformities subsequently developed on both sides in the postoperative period.

CONCLUSION

This case suggests that structures other than the growth plate are also capable of inducing cam deformity of the hip.

Twelve percent of hips with a primary cam deformity exhibit a slip-like morphology resembling sequelae of slipped capital femoral epiphysis

BACKGROUND

In some hips with cam-type femoroacetabular impingement (FAI), we observed a morphology resembling a more subtle form of slipped capital femoral epiphysis (SCFE). Theoretically, the morphology in these hips should differ from hips with a primary cam-type deformity.

QUESTIONS/PURPOSES

We asked if (1) head-neck offset; (2) epiphyseal angle; and (3) tilt angle differ among hips with a slip-like morphology, idiopathic cam, hips after in situ pinning of SCFE, and normal hips; and (4) what is the prevalence of a slip-like morphology among cam-type hips?

METHODS

We retrospectively compared the three-dimensional anatomy of hips with a slip-like morphology (29 hips), in situ pinning for SCFE (eight hips), idiopathic cam deformity (171 hips), and 30 normal hips using radial MRI arthrography. Normal hips were derived from 17 asymptomatic volunteers. All other hips were recruited from a series of 277 hips (243 patients) seen at a specialized academic hip center between 2006 and 2010. Forty-one hips with isolated pincer deformity were excluded. Thirty-six of 236 hips had a known cause of cam impingement (secondary cam), including eight hips after in situ pinning of SCFE (postslip group). The 200 hips with a primary cam were separated in hips with a slip-like morphology (combination of positive fovea sign [if the neck axis did not intersect with the fovea capitis] and a tilt angle [between the neck axis and perpendicular to the basis of the epiphysis] exceeding 4°) and hips with an idiopathic cam. We evaluated offset ratio, epiphyseal angle (angle between the neck axis and line connecting the center of the femoral head and the point where the physis meets the articular surface), and tilt angle circumferentially around the femoral head-neck axis. Prevalence of slip-like morphology was determined based on the total of 236 hips with cam deformities.

RESULTS

Offset ratio was decreased anterosuperiorly in idiopathic cam, slip-like, and postslip (eg, 1 o'clock position with a mean offset ranging from 0.00 to 0.14; p < 0.001 for all groups) compared with normal hips (0.25 ± 0.06 [95% confidence interval, 0.13-0.37]) and increased posteroinferiorly in slip-like (eg, 8 o'clock position, 0.5 ± 0.09 [0.32-0.68]; p < 0.001) and postslip groups (0.55 ± 0.12 [0.32-0.78]; p < 0.001) and did not differ in idiopathic cam (0.32 ± 0.09 [0.15-0.49]; p = 0.323) compared with normal (0.31 ± 0.07 [0.18-0.44]) groups. Epiphyseal angle was increased anterosuperiorly in the slip-like (eg, 1 o'clock position, 70° ± 9° [51°-88°]; p < 0.001) and postslip groups (75° ± 13° [49°-100°]; p = 0.008) and decreased in idiopathic cam (50° ± 8° [35°-65°]; p < 0.001) compared with normal hips (58° ± 8° [43°-74°]). Posteroinferiorly, epiphyseal angle was decreased in slip-like (eg, 8 o'clock position, 54° ± 10° [34°-74°]; p < 0.001) and postslip (44° ± 11° [23°-65°]; p < 0.001) groups and did not differ in idiopathic cam (76° ± 8° [61°-91°]; p = 0.099) compared with normal (73° ± 7° [59°-88°]) groups. Tilt angle increased in slip-like (eg, 2/8 o'clock position, 14° ± 8° [-1° to 30°]; p < 0.001) and postslip hips (29° ± 10° [9°-48°]; p < 0.001) and decreased in hips with idiopathic cam (-7° ± 5° [-17° to 4°]; p < 0.001) compared with normal (-1° ± 5° [-10° to 8°]) hips. The prevalence of a slip-like morphology was 12%.

CONCLUSIONS

The slip-like morphology is the second most frequent pathomorphology in hips with primary cam deformity. MRI arthrography of the hip allows identifying a slip-like morphology, which resembles hips after in situ pinning of SCFE and distinctly differs from hips with idiopathic cam. These results support previous studies reporting that SCFE might be a risk factor for cam-type FAI.

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.

Arthroscopic treatment of mild to moderate deformity after slipped capital femoral epiphysis: intra-operative findings and functional outcomes

PURPOSE

To identify intra-articular pathology during arthroscopic osteochondroplasty for slipped capital femoral epiphysis (SCFE)-related femoroacetabular impingement and determine functional outcomes after treatment.

METHODS

Nine hips in 9 patients (6 male and 3 female patients; mean age, 17.5 years; age range, 13.5 to 26.9 years) underwent hip arthroscopy for femoroacetabular impingement after in situ pinning of the SCFE. Medical records, radiographs, and intraoperative images were reviewed to determine the severity of disease and damage to the hip joints. For all patients, we obtained the modified Harris Hip Score and Hip Outcome Score (HOS) preoperatively and at a minimum of 12 months postoperatively, as well as a Likert scale of perceived change in physical activity.

RESULTS

All 9 treated patients had some degree of labral or acetabular cartilage injury at the time of arthroscopy, which was a mean of 58.6 months (range, 18 to 169 months) after in situ pinning. The alpha angle improved from 75° preoperatively to 46° postoperatively (P < .001). The mean follow-up period was 28.6 months (range, 12.6 to 55.6 months). The mean modified Harris Hip Score improved from 63.6 preoperatively to 91.4 postoperatively (P = .005). Similarly, the mean HOS activities-of-daily living scale improved from 70.2 to 93.3 (P = .010), and the HOS sports scale improved from 53.4 to 88.9 (P = .004). Most patients reported significant improvement on a physical-activity Likert scale, with 4 reporting much improved, 3 reporting improved, and 1 reporting slightly improved physical activity. One patient reported an unchanged activity level. No patients reported a worse activity level after surgery.

CONCLUSIONS

Post-SCFE cartilage and/or labral damage develops in patients with symptomatic mild to moderate SCFE deformity, and arthroscopic treatment improved functional outcomes in a small cohort of patients at short-term follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Long-term Evolution of Slipped Capital Femoral Epiphysis Treated by in Situ Fixation: A 26 Years Follow-up of 11 Hips

Slipped capital femoral epiphysis (SFCE) may lead to femoro acetabular impingement and long-term function impairment, depending on initial displacement and treatment. There are several therapeutic options which include in situ fixation (ISF). The objective of this study was to evaluate long-term functional and radiographic outcomes of patients with SFCE treated with ISF. We conducted a single-center, retrospective study evaluating the clinical and radiographic outcomes of SCFE in situ fixation with a mean follow-up of 26 years (10-47). Analysis of preoperative and last follow up radiographs was performed. The functional status of the hip was evaluated according to the Oxford hip score-12 and the radiographic osteoarthritis stage was rated according to Tönnis classification. Signs of femoro acetabular impingement were sought. Ten patients (11 hips) were included. The average initial slip was 33.5° (10-62). At final follow up, the average Oxford hip score was 19.3 (12-37), it was good for groups who had a small initial slip (16.7) or moderate (17) and fair for the severe group (27). Average Tönnis grade was 1.3 (0-3). The average alpha angle was 65.3° (50-80°). Femoro acetabular impingement was likely in 100% of patients with severe slip, in 50% of patients with moderate slip and in 33% of patients with a slight slip. In situ fixation generated poor functional results, substantial hip osteoarthritis and potential femoro acetabular impingement in moderate to severe SCFE's. However, in cases with minor displacement, functional and radiographic results are satisfactory. The cut off seems to be around 30° slip angle, above which other treatment options should be considered.

The evolution and concepts of joint-preserving surgery of the hip

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.