Traumatic Posterior Hip Dislocation and Epiphysiolysis in a High School Football Player with Successful Outcome at 4 Years Follow-up: A Case Report.

CASE: We describe a case of posterior hip dislocation in a 13-year-old boy after a contact football injury with attempted closed reduction resulting in complete separation of the epiphysis from the femoral neck metaphysis with associated femoral head fracture and posterior dislocation of the femoral head. Treatment was emergently performed with a greater trochanteric osteotomy, open reduction internal fixation using cannulated screws, and additional small diameter drill holes in the femoral head to promote blood flow. The patient did well postoperatively and at over 4 years follow-up had no evidence of avascular necrosis and returned to full athletics participation. CONCLUSION: Particular attention should be taken when reducing hip dislocations in the adolescent population who may be predisposed to epiphysiolysis. Preservation of periosteal soft-tissue attachments and the use of small diameter drill holes to promote femoral head blood flow may have contributed to the excellent outcome.

Slipped Capital Femoral Epiphysis: Diagnosis and Management.

Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in adolescents, occurring in 10.8 per 100,000 children. SCFE usually occurs in those eight to 15 years of age and is one of the most commonly missed diagnoses in children. SCFE is classified as stable or unstable based on the stability of the physis. It is associated with obesity, growth spurts, and (occasionally) endocrine abnormalities such as hypothyroidism, growth hormone supplementation, hypogonadism, and panhypopituitarism. Patients with SCFE usually present with limping and poorly localized pain in the hip, groin, thigh, or knee. Diagnosis is confirmed by bilateral hip radiography, which should include anteroposterior and frog-leg views in patients with stable SCFE, and anteroposterior and cross-table lateral views in unstable SCFE. The goals of treatment are to prevent slip progression and avoid complications such as avascular necrosis, chondrolysis, and femoroacetabular impingement. Stable SCFE is usually treated using in situ screw fixation. Treatment of unstable SCFE also usually involves in situ fixation, but there is controversy about timing of surgery and the value of reduction. Postoperative rehabilitation of patients with SCFE may follow a five-phase protocol.

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.

Epiphyseal separation of the proximal humerus after birth trauma.

The purpose of this study was to report a new entity of epiphyseal slipping, which is a slipping of the upper humeral epiphysis in neonates due to birth trauma, and reporting the results of their management. Eight neonates presented with pseudo-paralysis with associated shoulder swelling and pain on passive movements of the upper limb; the radiographs revealed slipping of the proximal humeral epiphyses in six cases and associated shoulder dislocations in the other 2 cases. Failed attempts of closed reduction were done for all cases; they were managed through open reduction of the slipping and relocation of the glenohumeral joint when dislocated. The deltopectoral approach was used for management, and the slipping was fixed with k-wires through the skin. A full painless range of motion of the shoulder was achieved in all patients; no limb-length discrepancy or deformity was detected and no recurrent shoulder dislocation. In the last follow-up, all radiographs showed an anatomic reduction of the epiphyses, and all the epiphyseal plates were open. All cases showed normally growing well-formed epiphyses with no evidence of a vascular necrosis or collapse. A new entity of epiphyseal slipping was reported in this study; slipping of the upper humeral epiphysis in neonates due to birth trauma whether it is associated with shoulder dislocation or not is a benign injury with excellent results with open reduction.

Persisting growth after prophylactic single-screw epiphysiodesis in upper femoral epiphysis.

BACKGROUND: Prophylactic fixation of the contralateral hip in cases of slipped upper femoral epiphysis is controversial. Therefore, using a single-cannulated screw has been widely accepted. However, differing reports exist on the occurrence of persisting growth after prophylactic epiphysiodesis. The aim of this retrospective study was to evaluate the presence of persisting growth of the upper femoral epiphysis after prophylactic fixation. METHODS: From 2006 until 2009, 11 children underwent prophylactic pinning using a single-cannulated 6.5-mm cancellous screw. Time to fusion, persisting growth, and overgrowing of the screw were measured on plain radiographs taken postoperatively and at least after the growth plate was fused. RESULTS: All patients except 1 (91%) showed a persisting growth of the epiphysis, and in 2 cases a hardware replacement was necessary. The mean increase of the femoral neck length was 8.2% (SEM 1.46%). Mean follow-up was 37 months (range, 12 to 49 mo). All patients had a Risser sign grade 0 at the time of surgery, and equal or less than grade 3, when the growth plate was fused. CONCLUSIONS: Despite previous reports that a prophylactic fixation using a single-cannulated cancellous screw is unproblematic and safe, we showed that in our series growth persistence was the rule and in some cases the physeal overgrowth necessitates a hardware replacement. Careful follow-up until fusion of the growth plate should be recommended.

Frequency of radiographic signs of slipped capital femoral epiphysiolysis sequelae in hip arthroplasty candidates for coxarthrosis.

INTRODUCTION: The rate of osteoarthritis of the hip secondary to slipped capital femoral epiphysis (SCFE) is a subject of debate, and its frequency is underestimated in particular because of subclinical forms that may not be diagnosed during childhood. HYPOTHESIS: The frequency of radiographic anomalies subsequent to SCFE in adults requiring hip arthroplasty is higher than that reported in recent studies (6% to 15%). MATERIALS AND METHODS: A prospective single-center epidemiological radiography study was performed by one observer. Hip X-rays of patients who were being treated by arthroplasty for advanced hip osteoarthritis between January 2010 and May 2012 were analyzed. The etiology of osteoarthritis was classified in each patient according to the data obtained (primary, SCFE, dysplasia, protrusio acetabuli, other). The lateral view head-neck index (LVHNI) was used to quantify posterior translation of the femoral head, and identify SCFE sequelae. RESULTS: One hundred and eighty-six hips were included. Osteoarthritis was considered primary in 51 patients (27.4%), secondary to dysplasia in 42 (22.5%), protrusio acetabuli in 38 (20.5%) or another disease in nine (4.9%) while 46 hips (24.7%) presented a radiographic image suggesting SCFE past history. SCFE type deformities were the primary etiology of osteoarthritis in patients less than 60years old (30/84 or 35.7%). The mean age of patients in the SCFE group was 56.2years old (26-80) compared to 66 (54-91) for the primary osteoarthritis group (P<0.0001). The mean LVHNI was 13% (9-24%) in the SFCE group, the mean body mass index was 27.1kg/m(2) (±3.5; 18.2-35.4) in the SFCE group and the male to female ratio was 7.3/1. CONCLUSION: Our study identified a population with a morphological SCFE type anomaly of the coxofemoral joint (LVHNI>9%), which results in the development of earlier osteoarthritis than that found in the rest of the population. SCFE is more common than reported in the literature because it is the first etiology of osteoarthritis of the hip in subjects less than 60years old. LEVEL OF EVIDENCE: Level III. Diagnostic prospective study with a control group.

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

BACKGROUND: The modified Dunn procedure has rapidly gained popularity as a treatment for unstable slipped capital femoral epiphysis (SCFE), but limited data exist regarding its safety and efficacy. The purpose of this study was to present results and complications following this procedure in a large multicenter series. METHODS: We reviewed the outcomes of all patients who had been treated with the modified Dunn procedure by five surgeons from separate tertiary-care institutions. All slipped capital femoral epiphyses were defined as unstable according to the Loder criteria. Patients with less than one year of follow-up and those with an underlying endocrinopathy or syndrome were excluded. All surgical procedures were performed by pediatric orthopaedic surgeons who had specific training in the modified Dunn procedure. Operative reports, outpatient records, and follow-up radiographs were used to determine the demographic information, type of fixation, final slip angle, presence of osteonecrosis, and any additional complications. Standardized surveys were administered to determine the pain level (0 to 10 scale), satisfaction (0 to 100 scale), function (modified Harris hip score, 0 to 91 scale), and activity level (UCLA [University of California Los Angeles] activity score, 0 to 10 scale) at time of the most recent follow-up. RESULTS: Twenty-seven patients (twenty-seven hips) with a mean of 22.3 months (range, twelve to forty-eight months) of follow-up met the inclusion criteria. Four patients (15%) had broken implants at three to eighteen weeks after surgery and required revision fixation. Seven patients (26%) developed osteonecrosis at a mean of 21.4 weeks (range, ten to thirty-nine weeks), with each surgeon having at least one case of osteonecrosis. The mean slip angle at the time of the most recent follow-up was 6° (95% confidence interval, 2° to 11°). Patients who did not develop osteonecrosis had significantly better clinical results compared with those who developed osteonecrosis, as demonstrated by a lower mean pain score (0.3 compared with 3.1, p = 0.002), higher level of satisfaction (97.1 compared with 65.8, p = 0.001), higher modified Harris hip score (88.0 compared with 60.0, p = 0.001), and higher UCLA activity score (9.3 compared with 5.9, p = 0.031). CONCLUSIONS: This largest reported series of unstable slipped capital femoral epiphyses treated with the modified Dunn procedure demonstrated that the procedure is capable of restoring anatomy and preserving function after a slip but that implant complications and osteonecrosis can and do occur postoperatively.

Slipped upper tibial epiphysis in infantile tibia vara: three cases.

We describe three cases of infantile tibia vara resulting from an atraumatic slip of the proximal tibial epiphysis upon the metaphysis. There appears to be an association between this condition and severe obesity. Radiologically, the condition is characterised by a dome-shaped metaphysis, an open growth plate and disruption of the continuity between the lateral borders of the epiphysis and metaphysis, with inferomedial translation of the proximal tibial epiphysis. All patients were treated by realignment of the proximal tibia by distraction osteogenesis with an external circulator fixator, and it is suggested that this is the optimal method for correction of this complex deformity. There are differences in the radiological features and management between conventional infantile Blount's disease and this 'slipped upper tibial epiphysis' variant.

Primary hyperparathyroidism presenting with bilateral slipped capital femur epiphysiolysis. A pictorial essay.

It has become rare to find the typical radiological manifestations of primary hyperparathyroidism like generalized osteoporosis, brown tumors and advanced bone resorption because of the generalized usage of biochemical screening techniques. We present a 17-year-old patient with a parathyroid adenoma resulting in these typical skeletal manifestation throughout the skeleton combined with secondary bilateral slipped capital femur epiphysiolysis.

Prediction of contralateral slipped capital femoral epiphysis using the modified Oxford bone age score.

BACKGROUND: The purpose of the present study was to determine whether the modified Oxford bone score can be used as a predictor for the risk of developing contralateral slipped capital femoral epiphysis (SCFE) in children who present with a unilateral slip. METHODS: We identified 260 patients treated for unilateral SCFE between 1980 and 2002 and followed them up to skeletal maturity or until development of contralateral slip. Exclusion criteria included patients with endocrine or metabolic disorder, Down syndrome, and those with radiographs inadequate to determine the modified Oxford bone score. The initial radiographs were given a score ranging from 16 to 26. Statistical analysis was used to determine whether the modified Oxford bone score was predictive of future development of contralateral slip. A linear regression model was used to estimate the probability of future development of a contralateral slip as related to the modified Oxford bone score. RESULTS: Of the 260 patients, 64 (24%) developed a contralateral slip, at an average of 10 months after initial presentation. Race, sex, age, and weight at initial presentation were not predictive of the development of contralateral slip. The modified Oxford score and a triradiate score of 1 were found to be significant (P<0.0001) predictors, with the modified Oxford score a better overall predictor. CONCLUSIONS: The modified Oxford bone age score is the best predictor of the risk of development of a contralateral SCFE in patients presenting with a unilateral slip. Controversy exists regarding prophylactic pinning of a normal hip in patients presenting with unilateral SCFE. The benefits of prophylactic pinning must outweigh risk. This study provides probability data for predicting a contralateral slip based on the modified Oxford bone maturity score that can be shared with families and allows physicians to decide their threshold for prophylactically pinning the contralateral hip in patients presenting with a unilateral slip. LEVEL OF EVIDENCE: Therapeutic level IV, Case series.

Bone apposition of the acetabular rim in deep hips: a distinct finding of global pincer impingement.

BACKGROUND: Hips with coxa profunda can develop a pincer-type impingement with linear impact between the proximal part of the femur and the acetabulum, leading to bone apposition on the acetabular rim. METHODS: Twenty hips with radiographic features of rim ossification were isolated from a pilot cohort of 220 patients for histologic assessment of the acetabular rim and the labrum. In the second part of the study, the prevalence of radiographic signs of bone apposition in a cohort of 148 hips treated for femoroacetabular impingement was assessed. RESULTS: Histologic analysis confirmed that the labrum may become displaced and replaced by the appositional bone formation. The double-line sign and the recess sign are suggestive of an ongoing process of this bone formation, and the described phenotypes of bone apposition indicate the site of the impingement problem. Morphological anomalies of the proximal part of the femur, such as a low neck-shaft angle or a short femoral neck, may further contribute to the mechanism of pincer impingement. CONCLUSIONS: In later stages, this bone formation cannot be distinguished from the native bone and the labrum may appear to be nearly absent on imaging studies. While the bone apposition on the rim is first reactive to chronic impingement, the impingement then increases and may lead to further bone apposition.

In situ fixation for slipped capital femoral epiphysis: perspectives in 2011.

Slipped capital femoral epiphysis is usually treated with in situ fixation to prevent progression of deformity. However, slipped capital femoral epiphysis always is associated with structural risk factors for hip dysfunction in addition to the risk of slip progression. Femoro-acetabular impingement causes some mechanical abnormality in every hip affected by slipped capital femoral epiphysis, even when the slip is mild. The severity of femoro-acetabular impingement caused by slipped capital femoral epiphysis depends on several factors. Cumulative injury to the articular cartilage can result from impingement, and it is better to prevent this type of injury than to treat it later. In situ fixation alone rarely relieves femoro-acetabular impingement in slipped capital femoral epiphysis. Skillful and precise in situ fixation allows careful analysis of hip function in the stabilized slip by eliminating the major risk of acute instability. The more subtle risk of long-term articular damage caused by femoro-acetabular impingement must be considered. The treatment of femoro-acetabular impingement in patients who have slipped capital femoral epiphysis is a separate issue from instability of the proximal femoral physis. Femoro-acetabular impingement must be assessed in every hip that is affected by slipped capital femoral epiphysis, even when the deformity is mild. Several treatment options exist for treating femoro-acetabular impingement associated with slipped capital femoral epiphysis.

Adolescent slipped capital femoral epiphysis treated by a modified Dunn osteotomy with surgical hip dislocation.

Between June 2001 and November 2008 a modified Dunn osteotomy with a surgical hip dislocation was performed in 30 hips in 28 patients with slipped capital femoral epiphysis. Complications and clinical and radiological outcomes after a mean follow-up of 3.8 years (1.0 to 8.5) were documented. Subjective outcome was assessed using the Harris hip score and the Western Ontario and McMaster Universities osteoarthritis index questionnaire. Anatomical or near-anatomical reduction was achieved in all cases. The epiphysis in one hip showed no perfusion intra-operatively and developed avascular necrosis. There was an excellent outcome in 28 hips. Failure of the implants with a need for revision surgery occurred in four hips. Anatomical reduction can be achieved by this technique, with a low risk of avascular necrosis. Cautious follow-up is necessary in order to avoid implant failure.

In situ fixation of slipped capital femoral epiphysis with Steinmann pins.

BACKGROUND AND PURPOSE: Slipped capital femoral epiphysis (SCFE) is often treated by surgical fixation; however, no agreement exists regarding technique. We analyzed the outcome of in situ fixation with Steinmann pins. PATIENTS AND METHODS: All 67 subjects operated for slipped capital femoral epiphysis at Haukeland University Hospital during the period 1990-2007 were included. All were treated by in situ fixation with 2 or 3 parallel Steinmann pins (8 mm threads at the medial end). The follow-up evaluation consisted of clinical examination and hip radiographs. Radiographic outcome was based on measurements of slip progression, growth of the femoral neck, leg length discrepancy, and signs of avascular necrosis and chondrolysis. RESULTS: 67 subjects (41 males) were operated due to unilateral slips (n = 47) or bilateral slips (n = 20). Mean age at time of diagnosis was 13 (7.2-16) years. Mean age at follow-up was 19 (14-30) years, with a mean postoperative interval of 6.0 (2-16) years. The operated femoral neck was 9% longer at skeletal maturity than at surgery, indicating continued growth of the femoral neck. At skeletal maturity, 12 subjects had radiographic features suggestive of a previous asymptomatic slip of the contralateral hip. The total number of bilateral cases of SCFE was 32, i.e half of the children had bilateral SCFE. 3 subjects required additional surgery and mild avascular necrosis of the femoral head was seen in 1 patient. None had slip progression or chondrolysis. INTERPRETATION: In situ pinning of SCFE with partly threaded Steinmann pins appears to be a feasible and safe method, with few complications. The technique allows further growth of the femoral neck.

Single screw fixation in stable and unstable slipped upper femoral epiphysis.

The aim of this single centre retrospective study was to assess the outcome of patients after the fixation of slipped upper femoral epiphysis (SUFE) using a single cannulated screw. Thirty-eight slips, 28 stable and 10 unstable were treated with single in-situ screw fixation. The minimum follow-up was 1 year. The overall adverse outcome in terms of avascular necrosis (AVN), chondrolysis and revision surgery for slip progression was 18%, which was considered satisfactory. Slip progression of more than 10° was higher in the unstable when compared with the stable group but not statistically significant. Two out of the nine satisfactorily fixed unstable slips required revision surgery as opposed to none in the stable group. The incidence of AVN in the unstable group was 20%. There were no cases of AVN in the stable group. The adverse outcome in terms of AVN, chondrolysis and revision surgery for slip progression was significantly higher in the unstable group. In our study, results of single screw fixation for SUFE were found to be satisfactory as shown by earlier studies with the unstable SUFEs as expected having a poorer outcome when compared with the stable SUFEs.

Acetabular morphology in slipped capital femoral epiphysis.

BACKGROUND: Children with unilateral slipped capital femoral epiphysis (SCFE) often appear to have overcoverage of their contralateral (normal) side. This increased coverage can be a contributing factor to femoroacetabular impingement. The purpose of this study was to quantify the coverage of the normal hip in patients with unilateral SCFE and to compare our results to matched controls. METHODS: Between 2003 and 2008, we identified 50 patients treated for unilateral, stable SCFE by in-situ screw fixation. Using postoperative anteroposterior and frog radiographs of the pelvis, the lateral center-edge angle (LCEA) and Tönnis angle (TA) were measured on the uninvolved side. Pelvic tilt was evaluated to ensure the quality of the radiographs, and in those patients with appropriate films, the presence or absence of a posterior wall sign and cross-over sign was noted. Results were compared with 50 age and sex-matched controls. Control data was generated from scout views of otherwise healthy patients who underwent an abdominal computed tomography scan to rule out acute appendicitis. RESULTS: The mean LCEA and TA of the contralateral acetabulum were 33 and 5 degrees, respectively (range: 18 to 47; -7 to 13). Seventy-eight percent had a positive cross-over sign and 39% had a posterior wall sign. In comparison, the mean LCEA and TA in our control group were 20 and 8 degrees, respectively (range: 8 to 35; -6 to 23). In this group, 21% had a positive cross-over sign whereas 15% had a positive posterior wall sign. We found a significantly higher LCEA and lower TA in the study population compared with controls (P=1.6E-16, 0.0003), as well as a higher prevalence of retroversion signs (P=5E-7, 0.02). CONCLUSIONS: The contralateral acetabulum in patients with treated unilateral SCFE demonstrates significantly more coverage compared with matched controls. In addition, there is a significantly higher prevalence of acetabular retroversion in these patients. Our findings should alert caregivers to the potential of developing femoroacetabular impingement on the contralateral side in patients who have had a unilateral SCFE. LEVELS OF EVIDENCE: III (retrospective case-control).

Revised modified Oxford bone score: a simpler system for prediction of contralateral involvement in slipped capital femoral epiphysis.

BACKGROUND: The decision to prophylactically treat the uninvolved hip in slipped capital femoral epiphysis (SCFE) remains controversial. The modified Oxford bone score (mOBS) is predictive of future contralateral involvement in slipped capital femoral epiphysis. The scoring method for this system is challenging to remember because out-of-context irrational number sequences and total score range (16 to 26) are used. This study was performed to evaluate intraobserver and interobserver reliability of the mOBS and to determine whether revising the scoring sequence to 0 to 2 for all 5 categories (total score range: 0 to 10) would be easier for orthopedic surgeons to remember. METHODS: Six orthopedic surgeons scored 30 normal pelvis radiographs using the mOBS (original or revised scoring system) on 2 separate occasions, at least 2 weeks apart, with the aid of reference diagrams and an explanatory key. At a later date, the observers were asked to complete blank reference diagrams from memory for both scoring systems (16 to 26 and 0 to 10). RESULTS: Intraobserver reliability was analyzed for each parameter independently and as a total score. Overall, intraobserver reliability was excellent, with total scores being within 1 and 2 points of each other 80.5% and 94.9% of the time, respectively. Interobserver reliability was very good, with total scores within 1 and 2 points of each other 69.6% and 87% of the time, respectively. None of the 6 observers were able to complete the blank mOBS key correctly from memory, despite being reminded of the 16 to 26-point range. Five of the 6 were able to correctly complete the revised key using the 0 to 10 point range system. CONCLUSIONS: The mOBS is a useful method to estimate risk of contralateral slip, with excellent intraobserver and very good interobserver reliability. Difficulty in remembering the original scoring scheme because of its illogic sequences in the modified method limits its clinical applicability. Revision of the mOBS to a consistent 0 to 2 (range: 0 to 10) system greatly enhanced the observers ability to recall the scoring system. LEVEL OF EVIDENCE: Level II - development of diagnostic criteria with reference to "gold" standard.

Treatment of slipped capital femoral epiphysis with a modified Dunn procedure.

BACKGROUND: Surgical procedures with use of traditional techniques to reposition the proximal femoral epiphysis in the treatment of slipped capital femoral epiphysis are associated with a high rate of femoral head osteonecrosis. Therefore, most surgeons advocate in situ fixation of the slipped epiphysis with acceptance of any persistent deformity in the proximal part of the femur. This residual deformity can lead to secondary osteoarthritis resulting from femoroacetabular cam impingement. METHODS: We retrospectively assessed the cases of twenty-three patients with slipped capital femoral epiphysis after surgical correction with a modified Dunn procedure, an approach that included surgical hip dislocation. The study reviewed the clinical status and radiographs made at the time of surgery, as well as the intraoperative findings. At a minimum follow-up of twenty-four months after surgery, the motion of the treated hip was compared with the motion of the contralateral hip, and the radiographic findings related to the anatomy of the femoral head-neck junction, as well as signs of early osteoarthritis or osteonecrosis, were evaluated. RESULTS: Twenty-one patients had excellent clinical and radiographic outcomes with respect to hip function and radiographic parameters. Two patients who developed severe osteoarthritis and osteonecrosis had a poor outcome. The mean slip angle of the femoral head of 47.6° preoperatively was corrected to a normal value of 4.6° (p < 0.0001). The mean flexion and internal rotation postoperatively were 107.3° and 37.8°, respectively. The mean range of motion of the treated hips was not significantly different (p > 0.05) from that of the normal, contralateral hips. Of the eight hips that were considered unstable in the intraoperative clinical assessment, six had been considered stable preoperatively. CONCLUSIONS: The treatment of slipped capital femoral epiphysis with the modified Dunn procedure allows the restoration of more normal proximal femoral anatomy by complete correction of the slip angle, such that probability of secondary osteoarthritis and femoroacetabular cam impingement may be minimized. The complication rate from this procedure in our series was low, even in the treatment of unstable slipped capital femoral epiphysis, compared with alternative procedures described in the literature for fixation of slipped capital femoral epiphysis.