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

Outcomes of the Modified Dunn Procedure Versus Delayed Imhauser Osteotomy for Moderate to Severe Stable Slipped Capital Femoral Epiphysis

BACKGROUND

Traditional management of moderate to severe stable slipped capital femoral epiphysis (SCFE) has been in situ fixation followed by reconstructive surgery if symptoms arise. This delayed approach may lead to irreversible intra-articular damage of the hip over time. The purpose of this study was to compare radiographic and clinical outcomes of the modified Dunn procedure (MDP) versus in situ fixation followed by delayed Imhauser osteotomy (DIO).

METHODS

This was a retrospective study from a single institution between 2001 and 2021. Among 250 patients diagnosed with SCFE, a total of 18 (18 hips) treated with MDP and 16 (18 hips) treated with DIO for moderate to severe stable SCFE were included. Most patients who underwent DIO either had concomitant (11/18 hips) or subsequent (2/18 hips) open osteochondroplasty. Mean follow up was 4.7 years (range: 1 to 12.8 y). Radiographs were reviewed to measure Southwick angle, anteroposterior and lateral alpha (α) angles, and femoral head-neck offset ratio preoperatively and at latest follow up. Charts were reviewed for demographics, subsequent surgeries, complications, and Heyman-Herndon clinical outcomes.

RESULTS

The amount of deformity correction was greater in the MDP than DIO group based on anteroposterior α angles (mean: 22.3 vs. 11.9 degrees, P=0.046) and femoral head-neck offset ratios (mean: 0.26 vs. 0.12, P=0.001). There was no significant difference in Heyman-Herndon scores (both 16/18, 88.9% good to excellent outcomes, P>0.999). Less reoperations were performed in the MDP than DIO group (2/18, 11.1% vs. 9/18, 50%; P=0.004). AVN occurred in 2/18 hips (11.1%) in the MDP group with both surgeries performed early in the series and underwent prior in situ screw fixation compared with 0/18 hips (0%) in the DIO group (P=0.486). One patient in the DIO group was later diagnosed with osteoarthritis.

CONCLUSIONS

MDP resulted in more anatomic coronal and sagittal plane deformity correction, less reoperations, and similar Heyman-Herndon clinical outcomes compared with DIO. AVN occurred in the MDP group whereas osteoarthritis occurred in the DIO group. These complications must be weighed against improved long-term clinical results for patients who would otherwise be at risk for premature degenerative joint disease due to residual proximal femoral deformity.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

MR-based Bony 3D models enable radiation-free preoperative patient-specific analysis and 3D printing for SCFE patients

Objectives

Slipped capital femoral epiphyses (SCFE) is a common pediatric hip disease with the risk of osteoarthritis and impingement deformities, and 3D models could be useful for patient-specific analysis. Therefore, magnetic resonance imaging (MRI) bone segmentation and feasibility of 3D printing and of 3D ROM simulation using MRI-based 3D models were investigated.

Methods

A retrospective study involving 22 symptomatic patients (22 hips) with SCFE was performed. All patients underwent preoperative hip MR with pelvic coronal high-resolution images (T1 images). Slice thickness was 0.8-1.2 mm. Mean age was 12 ± 2 years (59% male patients). All patients underwent surgical treatment. Semi-automatic MRI-based bone segmentation with manual corrections and 3D printing of plastic 3D models was performed. Virtual 3D models were tested for computer-assisted 3D ROM simulation of patients with knee images and were compared to asymptomatic contralateral hips with unilateral SCFE (15 hips, control group).

Results

MRI-based bone segmentation was feasible (all patients, 100%, in 4.5 h, mean 272 ± 52 min). Three-dimensional printing of plastic 3D models was feasible (all patients, 100%) and was considered helpful for deformity analysis by the treating surgeons for severe and moderate SCFE. Three-dimensional ROM simulation showed significantly (p < 0.001) decreased flexion (48 ± 40°) and IR in 90° of flexion (-14 ± 21°, IRF-90°) for severe SCFE patients with MRI compared to control group (122 ± 9° and 36 ± 11°). Slip angle improved significantly (p < 0.001) from preoperative 54 ± 15° to postoperative 4 ± 2°.

Conclusion

MRI-based 3D models were feasible for SCFE patients. Three-dimensional models could be useful for severe SCFE patients for preoperative 3D printing and deformity analysis and for ROM simulation. This could aid for patient-specific diagnosis, treatment decisions, and preoperative planning. MRI-based 3D models are radiation-free and could be used instead of CT-based 3D models in the future.

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.

Short-Term Complications of Relative Femoral Neck Lengthening Combined with Extra-Articular Osteotomies of the Proximal Femur

Purpose

Relative femoral neck lengthening (RNL) is a newer technique to correct coxa breva and coxa vara to relieve a femoro-acetabular impingement and improve hip abductor function without changing the position of the head on the shaft. Proximal femoral osteotomy (PFO) changes the position of the femoral head relative to the shaft. We studied the short-term complications of procedures that combined RNL with PFO.

Methods

All hips that underwent RNL and PFO using a surgical dislocation and extended retinacular flap development were included. Hips that were treated only with intra-articular femoral osteotomies (IAFO) were excluded. Hips that underwent RNL and PFO, with IAFO and/or acetabular procedures were included. Intra-operative evaluation of the femoral head blood flow was performed with the drill hole technique. Clinical evaluation and hip radiographs were obtained at 1 week, 6 weeks, 3 months, 6 months, 12 months and 24 months.

Results

Seventy two patients (31 males, 41 females, 6-52 years of age) underwent 79 combined RNL and PFO. 22 hips underwent additional procedures like head reduction osteotomy, femoral neck osteotomy, and acetabular osteotomies. There were 6 major and 5 minor complications noted. Two hips developed non-unions, both with basicervical varus-producing osteotomies. Four hips developed femoral head ischemia. Two of these hips avoided collapse with early intervention. One hip had persistent abductor weakness requiring hardware removal and three hips, all in boys developed symptomatic widening of the hip on the operated side from varus-producing osteotomy. One hip had asymptomatic trochanteric non-union.

Conclusion

RNL is routinely performed by releasing the short external rotator muscle tendon insertion from the proximal femur to raise the posterior retinacular flap. Though this technique protects the blood supply from direct injury, it seems to stretch the vessels with major corrections in the proximal femur. We recommend evaluating the blood flow intraoperatively and postoperatively and taking necessary steps early to decrease the stretch on the flap. It may be safer to avoid raising the flap for major extra-articular proximal femur corrections.

Significance

The results of this study suggest ways to improve the safety of procedures that combine RNL and PFO.

Assessment of femoral retroversion on preoperative hip magnetic resonance imaging in patients with slipped capital femoral epiphysis: Theoretical implications for hip impingement risk estimation

Purpose

Slipped capital femoral epiphysis is a common pediatric hip disease and was associated with femoral retroversion, but femoral version was rarely measured. Therefore, mean femoral version, mean femoral neck version, and prevalence of femoral retroversion were analyzed for slipped capital femoral epiphysis patients.

Methods

A retrospective observational study evaluating preoperative hip magnetic resonance imaging of 27 patients (49 hips) was performed. Twenty-seven untreated slipped capital femoral epiphysis patients (28 slipped capital femoral epiphysis hips and 21 contralateral hips, age 10-16 years) were evaluated (79% stable slipped capital femoral epiphysis, 22 patients; 43% severe slipped capital femoral epiphysis, 12 patients). Femoral version was measured using Murphy method on magnetic resonance imaging (January 2014-December 2021, rapid bilateral 3-dimensional T1 water-only Dixon-based images of pelvis and knee). All slipped capital femoral epiphysis patients underwent surgery after magnetic resonance imaging.

Results

Mean femoral version of slipped capital femoral epiphysis patients (-1° ± 15°) was significantly (p < 0.001) lower compared to contralateral side (15° ± 14°). Femoral version of slipped capital femoral epiphysis patients had significantly (p < 0.001) wider range from -42° to 35° (range 77°) compared to contralateral side (-5° to 44°, range 49°). Mean femoral neck version of slipped capital femoral epiphysis patients (6° ± 15°) was lower compared to contralateral side (11° ± 12°). Fifteen slipped capital femoral epiphysis patients (54%) had absolute femoral retroversion (femoral version < 0°). Six of the 12 hips (50%) with severe slips and 4 of the 8 hips (50%) with mild slips had absolute femoral retroversion (femoral version < 0°). Ten slipped capital femoral epiphysis patients (40%) had absolute femoral neck retroversion (femoral neck version < 0°).

Conclusion

Although slipped capital femoral epiphysis patients showed asymmetrically lower femoral version compared to contralateral side, there was a wide range of femoral version, underlining the importance of patient-specific femoral version analysis on preoperative magnetic resonance imaging. Absolute femoral retroversion was prevalent in half of slipped capital femoral epiphysis patients, in half of severe slipped capital femoral epiphysis patients, and in half of mild slipped capital femoral epiphysis patients. This has implications for anterior hip impingement and for surgical treatment with in situ pinning or femoral osteotomy (e.g. proximal femoral derotation osteotomy) or other hip preservation surgery.

Intertrochanteric Osteotomies in Children and Adolescents: Principles of Proximal Femoral Deformity Correction

Intertrochanteric osteotomies are used to correct a variety of congenital and acquired deformities of the proximal femur in children and adolescents. Varus, valgus, flexion, extension, or rotational osteotomies at the intertrochanteric level can be used to restore normal alignment of the proximal femur, increase congruency and stability of the hip joint, facilitate healing or remodeling of the femoral head and neck, redirect the articular surface, and improve functional limb position in the case of soft-tissue contractures. The steps necessary to assess proximal femoral deformity and plan the appropriate osteotomy are described along with indications and long-term considerations.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Is combined surgical dislocation and proximal femoral osteotomy a safe procedure for correction of complex hip deformities?

Complex deformities of the hip requiring intra-articular and proximal femoral correction are challenging with regard to surgical access and complication risk. Combined surgical dislocation and proximal femoral osteotomy (SD/PFO) is a surgical strategy that provides unrestricted access to the joint with the capability for adjunctive PFO. Although providing excellent surgical access, concerns over a potentially high risk of postoperative complications remain, and published information on the safety of this technique remain scarce. In this study, we defined the early complication profile of combined surgery across 48 hips with a variety of complex deformities using a standardized, validated complication grading scheme for hip preservation surgery. Patients were mean age 19.1 years 13–33 years and 60% had previous surgery. At the early mean follow-up of 2.9 years, considerable improvement was seen across all outcome scores. Major complications (Grade III or higher) occurred at a rate of 4.2% (n = 2). Both were osteotomy non-unions, and both were treated successfully with revision PFO and bone grafting at mean 1.1 years. To our knowledge, the current series of combined SD-PFO surgeries represents the largest to date for which detailed complication data have been reported. Given the complexity of these disorders, a major complication rate of 4.2% is acceptable. Our complication rates were comparable to those reported for isolated SD and PFO procedures. These rates did not vary significantly across morphologic variants or patient-specific characteristics. Additionally, our complication risk profile is consistent with previous, smaller reports, which supports the generalizability of these results among appropriately experienced surgeons.

Surgical treatment of slipped capital femoral epiphysis (SCFE) by Dunn procedure modified by Ganz: a systematic review

BACKGROUND

Treatment of SCFE is still controversial, especially in moderate and severe forms. Dunn osteotomy performed with the Ganz approach became very popular in the last decade, although it is a complicated and challenging surgical procedure with a risk of AVN. The aim of our study was to analyze the current literature verifying the effectiveness of this surgical procedure, with specific attention to the incidence of AVN and other complications.

MAIN BODY

A systematic review on the subject was performed according to the PRISMA guidelines. A literature search was performed by searching all published articles about the topic in the databases. The articles were screened for the presence of the following inclusion criteria: patients affected by slipped capital femoral epiphysis (SCFE) surgically treated by Dunn osteotomy using the Ganz surgical approach. All the patients affected by pathologies other than SCFE, treated without surgery or with procedures not including a surgical hip dislocation were excluded. Based on inclusion and exclusion criteria, 23 studies were included in our systematic review. Selected articles were published from 2009 to 2021 and they included 636 overall hips. According to the selected articles, Dunn osteotomy modified by Ganz, performed by an experienced surgeon, allows for anatomical reduction of moderate or severe SCFE with a low incidence of AVN.

CONCLUSIONS

The few papers with long term follow-up, reported no progression of hip osteoarthritis, however, since the patients are adolescent at surgery, longer follow-up studies are needed to validate this statement. It is still debated if better results are obtained in stable or unstable SCFE. The indication of this procedure in mild SCFE remains controversial.

LEVEL OF EVIDENCE

3.

Morscher's femoral neck lengthening osteotomy through surgical hip dislocation approach for preservation of Perthes and Perthes-like deformities

Background

Typical sequelae of Perthes disease and Perthes-like deformities comprise a short femoral neck, aspherical femoral head, and greater trochanteric overgrowth. Morscher's osteotomy aims at restoring the normal extra-articular anatomy, but incapable of restoring a normal head-neck contour with residual impingement. Femoral neck lengthening osteotomy combined with osteochondroplasty through surgical hip dislocation approach was not previously described in the literature. We hypothesized that this technique is capable of near-normal restoration of the proximal femoral anatomy, increasing limb length, restoring abductor power, and simultaneous management of intra-articular chondro-labral disease.

Methods

A prospective series of 21 consecutive patients with sequelae of Perthes disease and Perthes-like deformity (Stulberg II and III) were treated by Morscher's osteotomy through surgical hip dislocation approach. The mean age was 14.9 years (9-30 years) and the mean follow-up was 4.5 years (2-8 years).

Results

The mean Harris hip score improved significantly from 66.5 to 89.5 points (p < 0.001), and the mean limb length discrepancy improved from 2.5 to 0.6 cm (p < 0.001). The mean alpha angle improved from 81.8° to 49.5°, the mean neck-shaft angle increased from 117.8° to 129.8°, and the articulo-trochanteric distance has improved from -6.7 to 20.8 mm. Six out of 21 patients required staged periacetabular osteotomy for residual acetabular dysplasia. No cases of chondrolysis or osteonecrosis were identified.

Conclusion

Femoral neck lengthening osteotomy through surgical hip dislocation appraoch has proven to be safe and effective for preservation of symptomatic hips with Perthes and Perthes-like deformities and mild to moderate femoral head deformities (Stulberg II and III). A staged periacetabular osteotomy may be required in those patients with significant acetabular dysplasia.

Level of evidence

Level IV.

Mechanical Failure of 2 Cannulated Screw Fixation for Unstable SCFE: A Case Report

CASE

A 13-year-old obese boy presented with an acute-on-chronic unstable left slipped capital femoral epiphysis (SCFE). He underwent in situ surgical fixation with two 6.5-mm fully threaded cannulated screws. At 6 months, he presented with mechanical failure of both screws. He underwent screw removal, revision in situ fixation, a peritrochanteric flexion and internal rotational osteotomy, and an open femoroplasty. The osteotomy healed at 6 weeks. The femoral physis took an additional year to close.

CONCLUSION

This case highlights an uncommon complication of in situ pinning of SCFE, discusses revision fixation options, and suggests possible prolonged physeal closure in severe slips.

Simultaneous Morscher's osteotomy and arthroscopic debridement in the management of Legg-Calvé-Perthes disease: a case report and literature review

There is a lack of consensus around optimal surgical management for Legg–Calvé–Perthes Disease (LCPD). This case report discusses the benefits of combining arthroscopic femoral neck osteochondroplasty and labral repair with Morscher’s Osteotomy (MO) for LCPD. S.A. is a 17-year-old female diagnosed with LCPD at the age of 6 years and has long-standing right hip symptoms. An arthroscopic femoral neck osteochondroplasty and labral repair followed by MO was performed. The pre-operative and 8 months post-operative International Hip Outcome Tool (iHOT-12) scores were 16.3 and 79.8 out of 100, respectively, indicating better quality-of-life. Also, the femoral neck-shaft-angle (NSA) changed from 120 pre-operative to 138.7 post-operative to represent the correction of coxa vara. The literature review revealed no published reports describing combined MO with hip arthroscopic interventions in managing LCPD. Combined arthroscopic femoral neck osteochondroplasty (with labral repair) and MO provides high patient satisfaction and improves radiographic parameters in patients with LCPD.

How Common Is Femoral Retroversion and How Is it Affected by Different Measurement Methods in Unilateral Slipped Capital Femoral Epiphysis?

BACKGROUND

Although femoral retroversion has been linked to the onset of slipped capital femoral epiphysis (SCFE), and may result from a rotation of the femoral epiphysis around the epiphyseal tubercle leading to femoral retroversion, femoral version has rarely been described in patients with SCFE. Furthermore, the prevalence of actual femoral retroversion and the effect of different measurement methods on femoral version angles has yet to be studied in SCFE.

QUESTIONS/PURPOSES

(1) Do femoral version and the prevalence of femoral retroversion differ between hips with SCFE and the asymptomatic contralateral side? (2) How do the mean femoral version angles and the prevalence of femoral retroversion change depending on the measurement method used? (3) What is the interobserver reliability and intraobserver reproducibility of these measurement methods?

METHODS

For this retrospective, controlled, single-center study, we reviewed our institutional database for patients who were treated for unilateral SCFE and who had undergone a pelvic CT scan. During the period in question, the general indication for obtaining a CT scan was to define the surgical strategy based on the assessment of deformity severity in patients with newly diagnosed SCFE or with previous in situ fixation. After applying prespecified inclusion and exclusion criteria, we included 79 patients. The mean age was 15 ± 4 years, 48% (38 of 79) of the patients were male, and 56% (44 of 79) were obese (defined as a BMI > 95th percentile (mean BMI 34 ± 9 kg/m2). One radiology resident (6 years of experience) measured femoral version of the entire study group using five different methods. Femoral neck version was measured as the orientation of the femoral neck. Further measurement methods included the femoral head's center and differed regarding the level of landmarks for the proximal femoral reference axis. From proximal to distal, this included the most-proximal methods (Lee et al. and Reikerås et al.) and most-distal methods (Tomczak et al. and Murphy et al.). Most proximally (Lee et al. method), we used the most cephalic junction of the greater trochanter as the landmark and, most distally, we used the center base of the femoral neck superior to the lesser trochanter (Murphy et al.). The orientation of the distal femoral condyles served as the distal reference axis for all five measurement methods. All five methods were compared side-by-side (involved versus uninvolved hip), and comparisons among all five methods were performed using paired t-tests. The prevalence of femoral retroversion (< 0°) was compared using a chi-square test. A subset of patients was measured twice by the first observer and by a second orthopaedic resident (2 years of experience) to assess intraobserver reproducibility and interobserver reliability; for this assessment, we used intraclass correlation coefficients.

RESULTS

The mean femoral neck version was lower in hips with SCFE than in the contralateral side (-2° ± 13° versus 7° ± 11°; p < 0.001). This yielded a mean side-by side difference of -8° ± 11° (95% CI -11° to -6°; p < 0.001) and a higher prevalence of femoral retroversion in hips with SCFE (58% [95% CI 47% to 69%]; p < 0.001) than on the contralateral side (29% [95% CI 19% to 39%]). These differences between hips with SCFE and the contralateral side were higher and ranged from -17° ± 11° (95% CI -20° to -15°; p < 0.001) based on the method of Tomczak et al. to -22° ± 13° (95% CI -25° to -19°; p < 0.001) according to the method of Murphy et al. The mean overall femoral version angles increased for hips with SCFE using more-distal landmarks compared with more-proximal landmarks. The prevalence of femoral retroversion was higher in hips with SCFE for the proximal methods of Lee et al. and Reikerås et al. (91% [95% CI 85% to 97%] and 84% [95% CI 76% to 92%], respectively) than for the distal measurement methods of Tomczak et al. and Murphy et al. (47% [95% CI 36% to 58%] and 60% [95% CI 49% to 71%], respectively [all p < 0.001]). We detected mean differences ranging from -19° to 4° (all p < 0.005) for 8 of 10 pairwise comparisons in hips with SCFE. Among these, the greatest differences were between the most-proximal methods and the more-distal methods, with a mean difference of -19° ± 7° (95% CI -21° to -18°; p < 0.001), comparing the methods of Lee et al. and Tomczak et al. In hips with SCFE, we found excellent agreement (intraclass correlation coefficient [ICC] > 0.80) for intraobserver reproducibility (reader 1, ICC 0.93 to 0.96) and interobserver reliability (ICC 0.95 to 0.98) for all five measurement methods. Analogously, we found excellent agreement (ICC > 0.80) for intraobserver reproducibility (reader 1, range 0.91 to 0.96) and interobserver reliability (range 0.89 to 0.98) for all five measurement methods in healthy contralateral hips.

CONCLUSION

We showed that femoral neck version is asymmetrically decreased in unilateral SCFE, and that differences increase when including the femoral head's center. Thus, to assess the full extent of an SCFE deformity, femoral version measurements should consider the position of the displaced epiphysis. The prevalence of femoral retroversion was high in patients with SCFE and increased when using proximal anatomic landmarks. Since the range of femoral version angles was wide, femoral version cannot be predicted in a given hip and must be assessed individually. Based on these findings, we believe it is worthwhile to add evaluation of femoral version to the diagnostic workup of children with SCFE. Doing so may better inform surgeons as they contemplate when to use isolated offset correction or to perform an additional femoral osteotomy for SCFE correction based on the severity of the slip and the rotational deformity. To facilitate communication among physicians and for the design of future studies, we recommend consistently reporting the applied measurement technique.

LEVEL OF EVIDENCE

Level III, prognostic study.