[Osteonecrosis of the femoral head complicating prophylactic screw fixation for upper femoral epiphyolysis: case report and literature review]. / Ostéonécrose de la tête fémorale compliquant un vissage préventif d'une épiphysiolyse fémorale supérieure: cas clinique et revue de la littérature.

The therapeutic approach for the treatment of children with radiologically "normal" hip presenting with epiphysiolysis of the contralateral upper femur is controversial. We here report the case of a 12-year-old boy with osteonecrosis of radiologically "normal" and asymptomatic left femoral head prophylactically fixed due to acute femoral epiphysiolysis of the contralateral hip. Eight months after first surgery, the patient developed symptoms of avascular osteonecrosis of the femoral head. Specific criteria to be used in evaluating the most effective treatment between preventive screw or simple close monitoring exist. Despite these criteria, the risk of osteonecrosis in the "healthy" hip is not zero.

Disarticulation-Associated Femoral Head Separation in Clinically Normal Broilers: Histologic Documentation of Underlying and Predisposing Cartilage Abnormalities.

Routine and quantitative histologic studies on femoral head separation (FHS) associated with coxofemoral joint disarticulation at necropsy were conducted on 125 femoral heads collected from 21- to 50-day-old clinically normal broilers. The study compared groups demonstrating grossly detached femoral heads (DFHs) with those having attached femoral heads (AFHs). Marked microscopic lesions compatible with osteochondrosis (OCD) consistently occurred along the separation surface in the DFH population. The histologic changes consisted of cartilage degeneration and necrosis sometimes forming small clefts or microfractures. Hemorrhage and less frequent inflammatory cells were often present along the separation surfaces. Small foci of OCD in the femur occurred in the AFH group with lesser frequency and severity. The histologic changes were mainly found within the proximal proliferative zone of the physis near the epiphyseal junction. Histomorphometry disclosed significant quantitative reductions in chondrocyte density with increased pyknosis occurring adjacent to the separation site and to a lesser extent in deeper regions of the growth plate for the DFH compared with AFH. Measurements made along the separation surface of the percentage length occupied by osteochondrotic defects and actual separated cartilage disclosed significant differences between evaluation groups. However, determinations of vascular canal areas present within two or more regions of the growth plate revealed a slight and significant increased area for DFH compared with AFH. Severity scores for the occurrence of microthrombi within the growth plate showed no difference between the groups. The pathogenesis of FHS in broilers is related to defective cartilage production or degeneration resulting in increased fragility. This contrasts with the proposed pathogenesis of OCD in mammals, which involves ischemic necrosis due to underlying vascular defects. The results for the FHS-disarticulation model also differ from those reported for glucorticoid-induced femoral head necrosis in broilers. The FHS-associated lesions occurred without histologic evidence of bacterial chondritis or osteomyelitis.

Separación de la cabeza femoral asociada a la desarticulación en pollos de engorde clínicamente normales: documentación histológica de anomalías del cartílago subyacentes y predisponentes. Estudios histológicos de rutina y cuantitativos sobre la separación de la cabeza femoral (FHS) asociados con la desarticulación de la articulación coxofemoral durante la necropsia se realizaron en 125 cabezas femorales recolectadas de pollos de engorde clínicamente normales de 21 a 50 días de edad. El estudio comparó los grupos que demostraron cabezas femorales separadas (DFH) con los que tenían cabezas femorales unidas (AFH). Lesiones microscópicas marcadas compatibles con osteocondrosis (OCD) ocurrieron consistentemente a lo largo de la superficie de separación en la población de aves con cabezas femorales separadas. Los cambios histológicos consistieron en degeneración del cartílago y necrosis, formando a veces pequeñas hendiduras o microfracturas. La hemorragia y la presencia menos frecuente de células inflamatorias estaban presentes a lo largo de las superficies de separación. Se produjeron con menor frecuencia y gravedad, focos pequeños de osteocondrosis en el fémur en el grupo de aves con cabezas femorales unidas. Los cambios histológicos se encontraron principalmente en la zona proliferativa proximal de la fisis cerca de la unión epifisaria. La histomorfometría reveló reducciones cuantitativas significativas en la densidad de condrocitos con un aumento de la picnosis que ocurrió adyacente al sitio de separación y en menor medida en regiones más profundas de la placa de crecimiento en las aves con cabezas femorales separadas en comparación con las aves con cabezas femorales unidas. Las mediciones realizadas a lo largo de la superficie de separación del porcentaje de longitud ocupada por defectos osteocondróticos y con cartílago separado revelaron diferencias significativas entre los grupos de evaluación. Sin embargo, las determinaciones de las áreas del canal vascular presentes dentro de dos o más regiones de la placa de crecimiento revelaron un aumento leve y significativo del área para las aves con cabezas femorales separadas en comparación con las aves con cabezas femorales unidas. Las puntuaciones de severidad para la aparición de microtrombos dentro de la placa de crecimiento no mostraron diferencias entre los grupos. La patogenia de la separación de la cabeza femoral en pollos de engorde se relaciona con la producción o degeneración de cartílago defectuoso que resulta en un aumento de la fragilidad. Esto contrasta con la patogénesis propuesta para la osteocondrosis en mamíferos, que involucra necrosis isquémica debido a defectos vasculares subyacentes. Los resultados para el modelo de desarticulación-separación de la cabeza femoral también difieren de los reportados para la necrosis de la cabeza femoral inducida por glucorticoides en pollos de engorde. Las lesiones asociadas con la separación de la cabeza femoral ocurrieron sin evidencia histológica de condritis bacteriana u osteomielitis.

Análise do risco do escorregamento epifisário femoral proximal contralateral pelo escore de Oxford modificado / Analysis on the risk of contralateral proximal femoral epiphyseal slippage using the modified Oxford score

Objetivo: Determinar a aplicacão do escore de Oxford modificado em pacientes com escorre gamento epifisário femoral proximal (EEFP) no auxílio da indicacão do tratamento cirúrgico profilático dos quadris contralaterais. Métodos: Análise retrospectiva dos prontuários dos pacientes atendidos na instituicão na qual os autores trabalham. Foram selecionados aqueles com um tempo de seguimento mínimo de dois anos, atendidos de 2008 até 2011, que apresentaram EEPF unilateral. Os cri térios de exclusão foram pacientes com doenca endócrina ou metabólica, síndrome de Down e aqueles com radiografias inadequadas para determinar a pontuacão no escore de Oxford modificado. As radiografias iniciais receberam uma pontuacão que varia de 16 a 26. A aná lise estatística foi usada para determinar se a pontuacão foi preditiva do desenvolvimento futuro de deslizamento contralateral. Resultados: Dos 15 pacientes selecionados com EEFP unilateral, cinco (33,3%) evoluíram para o escorregamento contralateral. Os pacientes foram divididos em dois grupos, qua tro pacientes foram considerados de risco e desses três desenvolveram o escorregamento contralateral. No grupo sem risco havia 11 pacientes, dois evoluíram para o escorregamento contralateral. Nota-se assim uma tendência de que pacientes do grupo que desenvolveu a doenca difiram do grupo que não desenvolveu em relacão à classificacão de risco. Conclusão: Apesar de na nossa amostra a aplicacão do escore de Oxford modificado não ter sido estatisticamente significativa, notamos uma tendência para o escorregamento contra lateral nos quadris com escore baixo.

OBJECTIVE: To determine the application of the modified Oxford score among patients with proximal femoral epiphyseal slippage (PFES) as an aid to indicating prophylactic surgical treatment on the contralateral hip. METHODS: Retrospective analysis on the medical files of patients attended at the institution where the authors work. From these, patients attended between 2008 and 2011 who presented unilateral PFES and were followed up for a minimum of two years were selected. Patients were excluded if they presented endocrine disease, metabolic disease, Down syndrome or radiographs that were inadequate for determining the modified Oxford score. The initial radiographs received scores ranging from 16 to 26. Statistical analysis was used to determine whether the scoring was predictive of future development of contralateral slippage. RESULTS: Among the 15 patients with unilateral PFES that were selected, five (33.3%) evolved with contralateral slippage. The patients were divided into two groups. Four patients were considered to present risk and three of them developed contralateral slippage. In the group that was considered not to present risk, there were 11 patients and two of these evolved with contralateral slippage. Thus, there was a tendency for the patients in the group that developed the disease to differ from the group that did not develop it, in relation to the risk classification. CONCLUSION: Although application of the modified Oxford score was not statistically significant in our sample, we noted a tendency toward contralateral slippage among hips with low scores.

What is the best evidence for the treatment of slipped capital femoral epiphysis?

BACKGROUND: There are many different treatment methods for slipped capital femoral epiphysis (SCFE). It was the purpose of this study to review the results from the literature for different methods of SCFE treatment and on the basis of level of evidence determine the current best evidence treatment. METHODS: A systematic review of the literature was undertaken. Treatment results were grouped into 2 categories. The first was all methods without surgical hip dislocation, and the second was all methods in which surgical dislocation was used. RESULTS: For stable SCFEs without surgical dislocation, the best recommended treatment (mostly level IV) recommends in situ single screw fixation over multiple pin fixation, epiphysiodesis, osteotomy, or spica cast. For the unstable SCFEs without surgical dislocation (all level IV), the best recommended treatment is urgent reduction with decompression and internal fixation. For both stable and unstable SCFEs, the short-term small series in the literature (all level IV) does not demonstrate an advantage or improvement in outcomes compared with in situ single screw fixation for stable SCFE and urgent reduction, decompression, and internal fixation in unstable SCFEs. CONCLUSIONS: A systematic review of the literature recommends on the basis of level of evidence that the best treatment for a stable SCFE is single screw in situ fixation and for unstable SCFEs urgent gentle reduction, decompression, and internal fixation. LEVEL OF EVIDENCE: Level IV, systematic review of level IV studies.

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.

Screw placement after pinning of slipped capital femoral epiphysis: a postoperative CT scan study.

BACKGROUND: Unrecognized pin penetration in the treatment of slipped capital femoral epiphysis has serious long-term sequelae. The purpose of this study was to use postoperative computerized tomographic (CT) scans to determine the true position of the screw tip when compared with standard radiograph views. METHODS: Twenty-four patients with 33 slipped capital femoral epiphyses were included in the study. Intraoperative or postoperative radiographs [anteroposterior (AP) and frog lateral] were compared with postoperative CT scans (coronal and axial) to determine (1) distance of the screw tip from the subchondral bone of the femoral head, (2) the number of screw threads across the physis, and (3) the 3-dimensional placement of the screw tip in the femoral head. RESULTS: The positions of 38 screws in 33 hips were assessed. Screw position within specific quadrants of the femoral head was more anterior and superior than appreciated on radiographs. AP radiographs overestimated the distance between the screw tip and the subchondral bone, the average distance being 5.5 mm on AP radiographs and 3.4 mm on coronal CT (P<0.0001). Bland-Altman analysis confirmed 95% limits of agreement of -5.6 to 1.5 mm, indicating that screws could be up to 5.6 mm closer to the subchondral bone than estimated by the AP radiograph. Closer agreement was found between the frog lateral radiograph and the axial CT views, with the distance from the subchondral bone averaging 4.7 mm on frog lateral radiographs and 4.1 mm on axial CT (P<0.01). Bland-Altman analysis showed 95% limits of agreement between the 2 measures of -3.5 to 2.3 mm, suggesting that some screws were up to 3.5 mm closer to the subchondral bone. Three more anteriorly placed screws seemed to penetrate subchondral bone on CT, findings not shown on standard radiographs. CONCLUSIONS: Frog lateral radiographs of the hip provide a more accurate estimation of screw placement than AP radiographs. Screws closer than 4 mm to the subchondral bone on frog lateral radiographs or 6 mm on AP radiographs may penetrate subchondral bone.

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).

Radiographic assessment of bone remodelling in slipped upper femoral epiphyses using Klein's line and the α angle of femoral-acetabular impingement: a retrospective review.

BACKGROUND: Bone remodelling in patients with earlier slipped upper femoral epiphysis (SUFE) has been shown to have a generally positive effect on both clinical and radiologic parameters. This study aims to further assess the effect of bone remodelling on the femoral head-neck relationship in SUFE patients, with the aid of 2 radiographic measurements not earlier used for this assessment. METHODS: A retrospective review of radiographs was performed on all patients surgically managed for SUFE at a tertiary institution between 2000 and 2006. The postoperative and the most recent review radiographs were used for analysis. Alpha angles of Notzli (generally used to measure cam-type femoral-acetabular impingement) and displacement from Klein's line were measured as markers of femoral head-neck relationship. RESULTS: A total of 59 hips were evaluated with a median mean follow-up time of 17.7 months. Patients had mild-to-moderate SUFE. The postoperative α angle mean reduced by 17.7 degrees (95% confidence interval: 13.6-21.8, P<0.001) at follow up. The displacement from Klein's line improved by a mean of 4.8 mm (95% confidence interval: 3.9-5.8 mm, P<0.001), over the review period. CONCLUSIONS: The femoral head-neck relationship, measured by both the Notzli α angle and the displacement from Klein's line, becomes significantly closer to normal after in situ pinning of mild-to-moderate SUFE, compatible with favorable bone remodelling. Both of these indices show promise for use in prospective study and standardized clinical follow up of patients with SUFE, and could be especially useful in assessing for future femoral-acetabular impingement. LEVEL OF EVIDENCE: III.

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

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

The unstable slipped capital femoral epiphysis: risk factors for osteonecrosis.

BACKGROUND: The incidence of avascular necrosis (AVN) after unstable slipped capital femoral epiphysis (SCFE) varies widely in the literature (10% to 60%), and few studies have examined why certain unstable slips develop osteonecrosis whereas others do not. Our purpose was to determine risk factors for developing AVN after unstable SCFE. METHODS: We reviewed all unstable SCFEs treated primarily at our center. Medical records were reviewed to determine weight-percentile, age, length of prodromal symptoms, and time to treatment. Operative notes were used to classify treatment as either: (group 1) in situ screw fixation, (group 2) purposeful or inadvertent closed reduction and screw fixation, or (group 3) open reduction and internal fixation, and to determine whether or not the joint was decompressed during surgery. Preoperative radiographs were used to measure slip angle and percent translation. For group 2, these were compared with postoperative radiographs to calculate a Deltaslip angle and Deltatranslation. Student t tests and Fisher exact tests were used for statistical analysis. RESULTS: Of the 70 patients in our series, 14 developed AVN (20%). On the basis of treatment, 3 of 16 patients in group 1 (19%), 10 of 38 patients in group 2 (26%), and only 1 of 16 patients in group 3 (6%) developed AVN. Patients who developed osteonecrosis were significantly younger (11.67 y vs. 12.83 y, P=0.04) and had a significantly shorter duration of prodromal symptoms (17.5 d vs. 65.9 d, P=0.03) compared with those who did not develop AVN. None of the other factors were found to be significant. In a subgroup analysis looking solely at group 2 patients, those who developed AVN had a significantly higher initial slip angle compared with those who did not (62 degrees vs. 51 degrees, P=0.03). CONCLUSIONS: In this, the largest reported series of unstable slips treated with internal fixation, AVN seemed more likely to develop in younger patients with a shorter duration of prodromal symptoms. Patients undergoing open reduction may have a lower incidence of AVN, but our limited power precludes definitive conclusions. LEVEL OF EVIDENCE: Level IV (case series).

Slipped capital femoral epiphysis in a cerebral palsy patient: a case report.

This report is a case of slipped capital femoral epiphysis in a nonambulatory patient with spastic quadriplegic type of cerebral palsy. Such a case is unusual as no weight-bearing forces were acting on the hip; however, spasticity may have played a role. To the best of our knowledge no earlier cases have been reported in the literature.

Slipped capital femoral epiphysis: an ultrastructural study before and after osteosynthesis.

BACKGROUND AND PURPOSE: Several different theories have been proposed to explain the pathogenesis of slipped capital femoral epiphysis (SCFE). Using transmission electron microscopy (TEM), we carried out an ultrastructural study of core biopsy specimens of the physis at various stages of the disease. METHODS: Core biopsies were performed in 6 patients with different forms of SCFE during the first operation, and in 3 of them when removing the osteosynthesis material before physeal closure. The specimens were prepared for TEM examination. RESULTS: In 6 specimens obtained at first surgery, a marked distortion of the physeal architecture was observed. In 2 of the 3 specimens obtained at removal of the osteosynthesis material, the physis showed a more normal organization. INTERPRETATION: The improvement of the pathological alterations observed in the 2 cases after surgical intervention leads us to consider the possibility that when the growth plate is stabilized directly by pinning or indirectly by creating more optimal loading conditions with an intertrochanteric osteotomy, the morpho-functional characteristics of the physis can be restored and its growth process may resume.

[Herniation pits and their renaissance in association with femoroacetabular impingement]. / Herniation Pits und ihre Renaissance im Zusammenhang mit femoroazetabulärem Impingement.

Hernitation pits (HPs) of the femoral neck were first described in 1982. The purpose of this paper is to summarize the information concerning HPs published since then and to show their association with the diagnosis of femoroacetabular impingement (FAI) which has occurred within the last years. HPs are predominantly located at the anterior-superior femoral neck with a typical radiological appearance, which makes it possible to differentiate them from the numerous differential diagnoses mentioned. In the early publications HPs were described as a separate entity, while recent studies increasingly assign them to intra-osseous ganglia. In contrast to the early publications depicting HPs as an incidental finding, they are currently mainly mentioned in association with FAI and at the same time are partly considered to be a radiological indicator of FAI. In summary, HPs should always be recognized and documented because they may contribute to the diagnosis of FAI which is essential for preventing or delaying osteoarthritis of the hip joint in the early stage.

Cams and pincer impingement are distinct, not mixed: the acetabular pathomorphology of femoroacetabular impingement.

BACKGROUND: Many impinging hips are said to have a mix of features of femoral cam and an overcovered acetabulum causing pincer impingement. Correction of such a mixed picture by reduction of the cam lesion and the acetabular rim is the suggested treatment. QUESTIONS/PURPOSES: We therefore asked two questions: (1) Is the acetabulum in cam impingement easily distinguishable from the pincer acetabulum, or is there a group with features of both types of impingement? (2) Is version or depth of socket better able to distinguish cam from pincer impingement? METHODS: We analyzed the morphologic features of the acetabulum and rim profile of 20 normal, healthy hips, 20 with cams and 20 with pincers on CT. Pelvises were digitized, orientated to the best-fit acetabular plane, and a rim profile was plotted. RESULTS: Cam hips were shallower than normal hips, which in turn were shallower than pincer hips (84 degrees +/- 5 degrees versus 87 degrees +/- 4 degrees versus 96 degrees +/- 5 degrees, respectively). The rim planes of cam, normal, and pincer hips had similar version (23 degrees, 24 degrees, 25 degrees), but females were 4 degrees more anteverted than males. CONCLUSIONS: We concluded cam and pincer hips are distinct pathoanatomic entities. Cam hips are slightly shallower than normal, whereas pincers are deeper. CLINICAL RELEVANCE: Before performing surgery for cam-type femoroacetabular impingement, surgeons should consider measuring the acetabular depth. The cam acetabulum is shallower than normal and may be rendered pathologically shallow by acetabular rim resection leading to early joint failure.

MRI morphometry, cartilage damage and impaired function in the follow-up after slipped capital femoral epiphysis.

OBJECTIVE: To assess rotation deficits, asphericity of the femoral head and localisation of cartilage damage in the follow-up after slipped capital femoral epiphysis (SCFE). MATERIALS AND METHODS: Magnetic resonance imaging studies were obtained in adult patients with a history of SCFE. A total of 35 hips after SCFE in 26 patients (mean age 24.1 +/- 6.5, mean follow-up 11.9 +/- 6.1 years) were evaluated. The control group comprised 20 healthy hips from 10 young adults with an average age of 23.9 +/- 3.7 years. The MR protocol included a T1-weighted sequence with a 3D volumetric interpolated breath-hold sequence and a radial 2D proton density-weighted sequence around the femoral neck. Images were evaluated for alpha angle and cartilage damage in five positions around the femoral head. Hip function was evaluated at the time of MRI and correlated with MRI results. Mann-Whitney U test and Spearman's correlation coefficient were used for statistical analysis. RESULTS: In the hips after SCFE alpha angles were significantly increased in the anterosuperior (74.1 degrees +/- 18.8 degrees ) and superior (72.5 degrees +/- 21.5 degrees ) positions and decreased in the posterior position (25.0 degrees +/- 7.2 degrees ). Cartilage damage was dominant in the anterosuperior and superior positions. Impaired rotation significantly correlated with increased anterosuperior, superior and posterosuperior alpha angles. CONCLUSION: The data support an anterosuperior and superior cam-type deformity of the femoral head-neck junction in the follow-up after SCFE. MRI after SCFE can be used to assess anterosuperior and superior alpha angles, since the anterior alpha angle by itself may underestimate asphericity and is not associated with rotation deficits.

Osteopetrosis and congenital hypothyroidism complicated by slipped capital femoral epiphysis.

OBJECTIVE: To describe a 13-year-old girl with unilateral slipped capital femoral epiphysis (SCFE), who presented with an acute onset limp during follow-up for congenital hypothyroidism and osteopetrosis. METHODS: We present a case report detailing the patient's history as well as clinical, laboratory, and imaging findings and discuss the related literature. RESULTS: The patient had been diagnosed elsewhere with congenital hypothyroidism, and levothyroxine therapy was initiated when she was 20 days of age; however, adherence to the treatment was irregular. Both her weight and her height were below the 5th percentile, her breast development and pubic hair were consistent with Tanner stage 1, and she had mental retardation and atypical facies. Her gait was antalgic; no muscle atrophy or shortness in the affected leg was present. On laboratory investigation, thyroid function tests were concordant with primary hypothyroidism. Her bone age was estimated as 8 years. Dual-energy x-ray absorptiometry revealed increased bone mineral density. Radiographic studies disclosed striking opacity of the bones of the pelvis and sclerosis at the skull base. Computed tomography of the affected left lower limb showed a fragmented appearance of the capital femoral epiphysis and thickening and irregularities of the physis line on the left, consistent with SCFE. CONCLUSION: We underscore the possible facilitator role of osteopetrosis in the pathogenesis of SCFE, suggest the need to consider SCFE in the differential diagnosis when a lower extremity abnormality is detected in patients with congenital hypothyroidism or delayed puberty (or both), and emphasize this association with osteopetrosis.