Ischial spine sign reveals acetabular retroversion in Legg-Calvé-Perthes disease

A retrospective study describing the acetabular consequences of Legg- Calve-Perthes disease

PURPOSE

Legg Calve Perthes disease (LCPD) is a paediatric hip disorder caused by ischemia of the femoral epiphysis, causing femoral head deformity when untreated. This study aims to determine if previously validated pelvic obliquity radiographic parameters, used for assessing acetabular retroversion in developmental dysplasia of the hip, are applicable to patients with LCPD and its prognostic value.

METHOD

A retrospective study of patients with Legg Calve Perthes disease was carried out, analysing 4 pelvic parameters: Ilioischial Angle, Obturator Index, Sharp's Angle and Acetabular Depth-Width Ratio (ADR). The differences between healthy and affected hips were studied, and subsequently, it was assessed whether these parameters have prognostic value in the disease outcome.

RESULTS

Statistically significant differences have been obtained in the ilioischial angle, obturator index and ADR, between the affected and healthy hip. However, only the Acetabular Depth-Width Ratio showed predictive value for the disease outcome.

CONCLUSION

Although this study revealed differences in pelvic parameters between healthy and diseased hips, with only the ADR showing statistical significance in the disease's evolution and prognosis, further studies with larger sample sizes are necessary.

Long-Term Outcomes at Skeletal Maturity of Combined Pelvic and Femoral Osteotomy for the Treatment of Legg-Calve-Perthes Disease

Surgical treatment for Legg-Calve-Perthes disease (LCPD) is recommended for older children with moderate to severe disease. We sought to determine whether double osteotomies lead to improved radiologic outcomes compared to reported non-operative outcomes. Patients older than 6 years of age diagnosed with LCPD lateral pillar B or C who were treated with pelvic and femoral osteotomies were included. Radiologic outcomes and leg-length discrepancies were assessed using the Stulberg classification and were compared with the current literature. Fifteen hips in fourteen patients were treated with double osteotomy for LCPD, and seven had lateral pillar C disease (47%). The mean age at surgery was 8.6 years (range, 7.2-10.4) and the mean age at follow-up was 20.2 years (range, 14.2-35.6). At a mean 11.6-year follow-up (range: 6.3-25.2), double osteotomy resulted in 40% of patients having Stulberg I/II scores, 27% having Stulberg III scores, and 33% having Stulberg IV/V scores. The mean leg-length discrepancy was 1.4 cm in lateral pillar C patients compared to 0.8 cm in lateral pillar B patients. Four patients underwent additional surgeries, including two who required total hip arthroplasty. Double osteotomy as an alternative surgical procedure for the treatment of LCPD did not show improved outcomes when compared to historic non-operative cohorts.

Development of acetabular retroversion in LCPD hips-an observational radiographic study from early stage to healing

BACKGROUND

Acetabular retroversion is observed frequently in healed Legg-Calvé-Perthes disease (LCPD). Currently, it is unknown at which stage and with what prevalence retroversion occurs because in non-ossified hips, retroversion cannot be measured with standard radiographic parameters.

METHODS

In a retrospective, observational study; we examined pelvic radiographs in children with LCPD the time point of occurrence of acetabular retroversion and calculated predictive factors for retroversion. Between 2004 and 2017, we included 55 children with a mean age of 5.7 ± 2.4 years at diagnosis. The mean radiographic follow-up was 7.0 ± 4.4 years. We used two new radiographic parameters which allow assessment of acetabular version in non-ossified hips: the pelvic width index and the ilioischial angle. They are based on the fact that the pelvic morphology differs depending on the acetabular version. These parameters were compared among the four Waldenström stages and to the contralateral side. Logistic regression analysis was performed to determine predictive factors for acetabular retroversion.

RESULTS

Both parameters differed significantly among the stages of Waldenström (p < 0.003 und 0.038, respectively). A more retroverted acetabulum was found in stage II and III (prevalence ranging from 54 to 56%) compared to stage I and IV (prevalence ranging from 23 to 39%). In hips of the contralateral side without LCPD, the prevalence of acetabular retroversion was 0% in all stages for both parameters. Predictive factors for retroversion were younger age at stage II and IV, collapse of the lateral pillar in stage II or a non-dysplastic hip.

CONCLUSIONS

This is the first study evaluating acetabular version in children with LCPD from early stage to healing. In the developing hip, LCPD may result in acetabular retroversion and is most prevalent in the fragmentation (stage II) and early healing stage (stage III). Partial correction of acetabular retroversion can occur after healing. This has a potential clinical impact on the timing and type of surgical correction, especially in pelvic osteotomies for correction of acetabular version.

LEVEL OF EVIDENCE

Level III, retrospective observational study.

Retroversion of the hemipelvis rather than hypoplastic posterior wall decreases acetabular anteversion in hips affected by Perthes disease

The acetabular retroversion has a moderate incidence of 31-60% in all patients of the Perthes disease. It might be caused by posterior wall dysplasia based on recent animal researches. However, some studies support that hemipelvic retroversion is the main factor for the acetabular retroversion. The primary pathological factor of increasing retroversion angle is still controversial anatomically. This study aimed to identify whether there is acetabular retroversion in children with Perthes disease,and to find a method to distinguish version types. Forty children with unilateral Perthes disease who were admitted to our hospital from January 1, 2012 to December 31, 2018 were enrolled, and 40 controls were matched based on sex and age. The acetabular anteversion angle (AAA), internal wall anteversion angle (IWAA), anterior wall height of the acetabulum (A), acetabular posterior wall height (P), and acetabular width (W) were assessed on computed tomography (CT) at the level of the femoral head center. The acetabular wall difference index (AWDI; AWDI = P-A)/W*100) was calculated. The mean AAA was significantly lower in Perthes disease hips (10.59 (8.05-12.46)) than in contralateral hips (12.04 (9.02-13.33)) (p = 0.002) but did not differ from control hips (9.68 ± 3.76) (p = 0.465). The mean IWAA was significantly lower in Perthes hips (9.16 ± 3.89) than in contralateral hips (11.31 ± 4.04) (p = 0.000) but did not differ from control hips (9.43 ± 3.82) (p = 0.753). The mean AWDI did not differ between Perthes hips (0.41 ± 4.94) and contralateral hips (- 1.12 (- 4.50, 2.17)) (p = 0.06) or control hips (- 0.49 ± 5.46) (p = 0.437). The mean W was significantly higher in Perthes hips (44.61 ± 5.06) than in contralateral hips (43.36 ± 4.38) (p = 0.000) but did not differ from control hips (45.02 ± 5.01) (p = 0.719). The mean A and P did not differ between Perthes hips and contralateral hips or control hips. Correlation analysis of all hip joints revealed a significant correlation between AAAs and IWAAs (r = 0.772; r = 0.643; r = 0.608; and r = 0.540). Linear regression analysis revealed that AAAs increased with IWAAs. Multiple linear regression showed that IWAAs and AWDIs have good predictive value for AAAs in both Perthes and control hips (R² = 0.842, R² = 0.869). In patients with unilateral Perthes disease, the affected acetabulum is more retroverted than that on the contralateral side, which may be caused by hemipelvic retroversion. The measurements in this study could distinguish the form of acetabular retroversion. IWAAs and AWDIs can be used as new observations in future studies of acetabular version.

The acetabulum in healed Legg-Calvé-Perthes disease is cranially retroverted and associated with global reduction of femoral head coverage: a matched-cohort study

To evaluate the acetabular morphology in healed Legg–Calvé–Perthes disease after skeletal maturity using computed tomography (CT) scan and to compare with matched controls. We identified 33 (37 hips) patients with healed Legg–Calvé–Perthes disease and closed triradiate cartilage who underwent pelvic CT scan. Each patient was matched based on sex, age and side to a subject with no history of hip disease who had undergone pelvic CT evaluation because of abdominal pain. Both cohorts had 23 (70%) males and mean age of 16.4–16.5 ± 3.6 years. Two independent readers assessed lateral center-edge angle (LCEA), acetabular inclination angle (IA), acetabular depth-width ratio (ADR), acetabular version 10 mm below the dome (cranial) and at the acetabular center and anterior (AASA) and posterior acetabular sector angles (PASA). All measurements had good to excellent interobserver agreement (intraclass coefficients ≥ 0.87). The hips in the Legg–Calvé–Perthes disease cohort had a smaller mean ± standard deviation (SD) superior, anterior and posterior acetabular coverage as assessed by LCEA (13.2° ± 10.7° versus 28.2° ± 3.4°; P < 0.0001), IA (11.6° ± 6.7° versus 3.5° ± 2.8°; P < 0.0001), AASA (52.4° ± 9.5° versus 59.3° ± 5.0°; P = 0.001) and PASA (79.3° ± 5.9° versus 92.3° ± 5.5°; P < 0.0001) compared with controls. The acetabulum was shallower (ADR 287 ± 45 versus 323 ± 28; P = 0.0002) and the acetabular version was decreased cranially (0.4°±9.2° versus 8.2°±6.8°; P = 0.0002) and at the acetabular center (13.7°±5.1° versus 17.2° ±3.8°; P = 0.004) in Legg–Calvé–Perthes disease hips. After skeletal maturity, hips with healed Legg–Calvé–Perthes disease have shallower and more cranially retroverted acetabula, with globally reduced coverage of the femoral head compared with age-, sex- and side-matched control hips.

Age-related change and gender differences in pelvic morphology of healthy children

BACKGROUND

An increasing number of studies about the hip joint morphology with childhood-specific hip diseases have been reported. But there have been few reports on pelvic morphology of healthy children. The purpose of this study was to assess the pelvic morphology of healthy children in detail and clarify the age-related change and gender difference of it.

METHODS

We retrospectively assessed the pelvic morphology of 97 healthy children (3-18 years old) using their pelvic computed tomography (CT) data. Superior iliac angle (SIA), inferior iliac angle (IIA), and ischiopubic angle (IPA) as the parameters of pelvic winging, and acetabular anteversion and anterior acetabular sector angle (AASA), posterior acetabular sector angle (PASA), superior acetabular sector angle (SASA) as the parameters of acetabular coverage, are measured. Pearson's correlation coefficient was used for examining the correlation between the each measurement and the age of cases. Multiple linear regression analysis was performed to investigate the possibility of association of age and sex with each measurement.

RESULTS

In female, it was found that IIA, AASA, PASA, SASA were significantly correlated with the age of the cases. And in male, SIA, IIA, IPA, AASA, PASA were significantly correlated with the age. Multiple linear regression analysis revealed the significant difference of the distribution between males and females was observed in IIA, IPA, AVcen, PASA, and these measurements were lager for female.

CONCLUSIONS

In this study, we revealed the age-related change and gender difference of the pelvic morphology of healthy children, and this could be useful information in evaluating the hip with what appears to be an abnormal acetabular anteversion and acetabular inclination in the patients with childhood specific hip disease. Additionally, it will also help us to make operation plans pertaining to the hip.

Ischemic femoral head osteonecrosis in a piglet model causes three dimensional decrease in acetabular coverage

Legg-Calve-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis marked by development of severe femoral head deformity and premature osteoarthritis. The pathogenesis of femoral head deformity has been studied extensively using a piglet model of ischemic osteonecrosis, however, accompanying acetabular changes have not been investigated. The purpose of this study was to determine if acetabular changes accompany femoral head deformity in a well-established piglet model of LCPD and to define the acetabular changes using three dimensional computed tomography (3-D CT) and modeling. Twenty-four piglets were surgically induced with ischemic osteonecrosis on the right side. The contralateral hip was used as control. At 8 weeks postoperative, pelvi were retrieved and imaged with CT. Custom software was used to measure acetabular morphologic parameters on 3-D CT images. Moderate to severe femoral head deformities were present in all animals. Acetabula with accompanying femoral head deformity had a significant decrease in acetabular version and tilt (p < 0.001) and in coverage angle in the superior, posterior, and inferior quadrants (p < 0.05). These findings indicate that the development of femoral head deformity following ischemic osteonecrosis produces specific and predictable changes to the shape of the acetabulum. Acetabular changes described in patients with LCPD were observed in the piglet model. This model may serve as a valuable tool to elucidate the relationship between femoral head and acetabular deformities. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1173-1177, 2018.

Skeletal immaturity, rostral sparing, and disparate hip morphologies as biomechanical causes for Legg-Calvé-Perthes' disease

Legg-Calvé-Perthes' (Perthes') disease is a developmental disease of the hip joint that may result in numerous short and long term problems. The etiology of the disease remains largely unknown, but the mechanism is believed to be vascular and/or biomechanical in nature. There are several anatomical characteristics that tend to be prevalent in children with Perthes' disease, namely: skeletal immaturity, reduced height, and rostral sparing. We present an overview of the literature, summarizing the current understanding of the pathogenesis, particularly related to how the formation of the vasculature to the femoral epiphysis places children aged 5-8 at a higher risk for Perthes' disease, how skeletal immaturity and rostral sparing could increase the probability of developing Perthes' disease, and how animal models have aided our understanding of the disease. In doing so, we also explore why Perthes' disease is correlated to latitude, with populations at higher latitudes having higher incidence rates than populations closer to the Equator. Finally, we present five hypotheses detailing how Perthes' disease could have a biomechanical cause. Clin. Anat. 29:759-772, 2016. © 2016 Wiley Periodicals, Inc.

The presentation of Legg-Calvé-Perthes disease in females

PURPOSE

Legg-Calvé-Perthes disease (LCPD) is uncommon in girls. The presentation of LCPD in female patients has been reported as later in onset and associated with certain high-impact activities. Our aim is to characterize the presentation of female LCPD at a large center, with particular attention to the clinical and radiographic features of late-onset disease (>ten years of age). We perceived an increasing burden of late-onset disease with adult-like radiographic features.

METHODS

All patients presenting to a single large urban children's hospital from 1990-2014 with a diagnosis of LCPD were reviewed. Demographic, clinical, and radiographic data for all female patients were examined and compared to historical norms.

RESULTS

Four-hundred and fifty-one patients presented with LCPD in the study period, of which 82 (18.2 %) were female. The average age at presentation was 6.58 years in girls, which is similar to the classically reported mean age. Fourteen patients participated in high-impact repetitive activities or those with deep flexion and abduction, although few were late presenters. There were four female patients who presented for initial diagnosis >ten years of age.

CONCLUSIONS

There was a paucity of late-onset LCPD in girls in the study population, and the females with LCPD had a very similar age and character to their presentation as did males. Although their presentation is infrequent, three of four older females with LCPD were engaged in high-level physical activity, and their disease may be attributed to high-impact, repetitive athletics.

LEVEL OF EVIDENCE

Case series, Level IV.

Periacetabular osteotomy: a review of swiss experience

Symptomatic dysplasia of the hip and acetabular retroversion are possible causes of osteoarthritis in the young adult. Surgical management with reorientation of the acetabulum allows causal therapy of the deformity and preservation of the native hip joint. The Ganz' periacetabular osteotomy permits a free 3-dimensional reorientation of the acetabulum and respects the blood supply of the acetabular fragment. The posterior column remains intact with a stable fixation of the acetabular fragment and a preserved shape of the true pelvis. There is a significant learning curve with severe complications in up to 30 % of cases. Good results can be expected in the long-term follow-up if performed with correct indication at young age in hips with preserved joint cartilage and proper reorientation of the acetabular fragment. Overall survivorship is superior to the natural course of hip dysplasia with a preserved hip joint in 61 % after 20 years.

The acetabulum in Perthes' disease: inter-observer agreement and reliability of radiographic measurements

BACKGROUND AND PURPOSE

Perthes' disease leads to radiographic changes in both the femoral head and the acetabulum. We investigated the inter-observer agreement and reliability of 4 radiographic measurements assessing the acetabular changes.

PATIENTS AND METHODS

We included 123 children with unilateral involvement, femoral head necrosis of more than 50%, and age at diagnosis of 6 years or older. Radiographs were taken at onset, and 1 year and 5 years after diagnosis. Sharp's angle, acetabular depth-width ratio (ADR), lateral acetabular inclination (LAI), and acetabular retroversion (ischial spine sign, ISS) were measured by 3 observers. Before measuring, 2 of the observers had a consensus meeting.

RESULTS

We found good agreement and moderate to excellent reliability for Sharp's angle for all observers (intra-class correlation coefficient (ICC) > 0.80 with consensus, ICC = 0.46-0.57 without consensus). There was good agreement and substantial reliability for ADR between the observers who had had a consensus meeting (ICC = 0.62-0.89). Low levels of agreement and poor reliability were found for observers who had not had a consensus meeting. LAI showed fair agreement throughout the course of the disease (kappa = 0.28-0.52). The agreement between observations for ISS ranged from fair to good (kappa = 0.20-0.76).

INTERPRETATION

Sharp's angle showed the highest reliability and agreement throughout the course of the disease. ADR was only reliable and showed good agreement between the observers when landmarks were clarified before measuring the radiographs. Thus, we recommend both parameters in clinical practice, provided a consensus is established for ADR. The observations for LAI had only fair agreement and ISS showed inconclusive agreement in our study. Thus, LAI and ISS can hardly be recommended in clinical practice.

Outcomes of modified Dega acetabuloplasty in acetabular dysplasia related to developmental dislocation of the hip

Developmental dislocation of the hip (DDH) is frequently, even after reduction, associated with residual acetabular dysplasia. Various surgical techniques are used to correct this, one of which is Dega acetabuloplasty. This osteotomy technique has, however, rarely been assessed in this particular indication. The present study therefore sought to describe the technical details, report clinical and radiological results, and present limitations.

HYPOTHESIS

Unlike reorientation osteotomy in children, Dega acetabuloplasty does not lead to a high rate of acetabular retroversion at the end of growth.

PATIENTS AND METHODS

Sixteen Dega acetabuloplasties in 15 patients were assessed on joint range of motion, limp, lower limb length discrepancy and impaired everyday activity, pre-operatively and at end of follow-up. Hips were classified following Wicart et al. (2003). Radiologic assessment comprised Wiberg angle and acetabular index, pre- and post-operatively and at follow-up. Acetabular retroversion was analyzed by crossover sign, and hips were classified following Severin.

RESULTS

Median age at surgery was 3 years (range, 1.1-12.2 years) and 10 years (6.4-17.8) at end of follow-up. At end of follow-up, all hips were pain-free and classified as Wicart A, and all activities were allowed. Radiologically, hips were classified as Severin I, II or IV, in 11 (68.5%), 4 (25%) and 1 (6.5%) cases respectively. Wiberg angle rose from a mean 3.3° (-30° to 30°) to 23° (10° to 38°) and acetabular index fell from a mean 31° (25° to 45°) to 20° (5° to 30°) with surgery, and both continued to improve over follow-up: 26° (12-45°) and 13° (3-24°) respectively (P<0.05). Acetabular retroversion was found in 2 of the 10 hips with Y cartilage fusion.

DISCUSSION

Modified Dega acetabuloplasty was effective in correcting acetabular dysplasia in DDH. Functional and radiological results were good, with a low rate of acetabular retroversion (2/10), unlike with other techniques.

LEVEL OF EVIDENCE

Level IV. Therapeutic study.

Reduced head-neck offset in nontraumatic osteonecrosis of the femoral head

INTRODUCTION

Risk factors for nontraumatic osteonecrosis of the femoral head have in common that they trigger intravascular coagulation and thus lead to devascularization of the femoral head. In part of the patients, however, no risk factors seem to be evident. Mechanical reasons contributing to nontraumatic osteonecrosis have not been discussed so far. We hypothesized that recurrent traumatization of the vessels supplying the femoral head by a cam-type mechanism as in femoroacetabular impingement could add to intravascular coagulation. We, therefore, asked whether structural abnormalities at the femoral head-neck junction indicative of such a mechanism could be observed in radiographs of patients with osteonecrosis of the femoral head.

MATERIALS AND METHODS

The preoperative anteroposterior and lateral radiographs of 77 patients who underwent surgery because of osteonecrosis of the femoral head were retrospectively screened for a reduced head-neck offset by measuring the α-angle. For comparison, the α-angle was measured on anteroposterior and lateral radiographs of 339 control subjects without evident underlying hip pathology.

RESULTS

The mean α-angle was 62.8° (SD 18.7°) for anteroposterior and 67.6° (SD 13.2°) for lateral radiographs in patients with nontraumatic osteonecrosis of the femoral head, whereas in control subjects, the mean α-angle was 47.2° (SD 9.6°) (p < 0.0001) and 47.6° (SD 10.3°) (p < 0.0001), respectively.

CONCLUSIONS

A reduced head-neck offset in patients with nontraumatic osteonecrosis of the femoral head may act as a mechanical (co-)factor in developing osteonecrosis of the femoral head.

Acetabular version on magnetic resonance imaging: analysis of two different measuring techniques

BACKGROUND

Both increased anteversion and retroversion of the acetabulum can lead to clinical problems. Although computed tomography (CT) is the gold standard in acetabular version imaging, magnetic resonance imaging (MRI) is becoming increasingly popular. We conducted this retrospective study to answer the following questions: 1) can the bony landmarks necessary to outline and measure acetabular version on MRI be consistently and reproducibly identified; 2) are soft-tissue (labral) landmarks comparable to bony landmarks for the measurement of acetabular version?

METHODS

Twenty-nine MRI torsional profile examinations were studied. A total of 232 readings (116 each for right and left sided acetabulae) were involved. Acetabular anteversion angle (AAA) was measured using two different methods (i.e. bony acetabulum landmarks and labrum), by two investigators, at two separate times.

RESULTS

Mean age was 13 years, 8 months with a range of 14 years. There were 12 male patients and 17 female. It was possible to consistently identify bony and labral landmarks in all MR images. AAA measurements using both methods were consistent and reproducible. When comparing the two methods to each other we found them to be in excellent agreement with an ICC of 0.943 (95% confidence interval, 0.927 to 0.956), 37% of all readings were in perfect agreement and 97% were within 5 degrees. The mean difference in measurement between methods was 1.34 degrees.

CONCLUSION

Measurement of acetabular version using MRI remains consistent independent of the method used (bone versus labrum). MRI can provide adequate information for calculating acetabular version.

Acetabular retroversion in post slipped capital femoral epiphysis deformity

PURPOSE

While the femoral deformity in post slipped capital femoral epiphysis (SCFE) hips has been implicated in the development of femoral acetabular impingement, little has been studied about the acetabular side. The purpose of our study was to determine the frequency of morphologic changes suggestive of acetabular retroversion in patients who have sustained a SCFE.

METHODS

IRB approval was obtained and the records of patients from 1975 to 2010 were searched for ICD-9 codes for SCFE. A total of 188 patients were identified for the study. Two observers evaluated AP radiographs for evidence of acetabular retroversion as characterized by the presence of either an ischial spine sign or a crossover sign. Demographic data, date of onset, and treatment were recorded. For analysis, the right hip was used in patients with bilateral involvement.

RESULTS

Of the 188 patients identified, 5 patients had an incorrect diagnosis and 41 patients had missing or inadequate films, leaving 142 patients (284 hips) for review. 57 patients (114 hips) had bilateral SCFE and 85 patients had unilateral SCFE. 79 % (n = 45) of the right hips with bilateral SCFE and 82 % (n = 70) of the unilateral involved hips had at least one sign of retroversion. Uninvolved hips had at least one sign of retroversion 76 % (n = 65) of the time.

CONCLUSIONS

When compared to previously published values for normal patients, patients with SCFE appear to have an increased incidence of acetabular retroversion.

MRI abnormalities of the acetabular labrum and articular cartilage are common in healed Legg-Calvé-Perthes disease with residual deformities of the hip

BACKGROUND

Varying degrees of femoral deformity may result as Legg-Calvé-Perthes disease heals. Our aims were to investigate the prevalence of abnormalities of the acetabular labrum and cartilage, using noncontrast magnetic resonance imaging, and to correlate the findings with radiographic deformities that may exist after the healing of Legg-Calvé-Perthes disease.

METHODS

In a sample of ninety-nine patients with healed Legg-Calvé-Perthes disease, anteroposterior and lateral radiographs were used to assess the Stulberg classification, femoral head size and sphericity, femoral neck morphology, and acetabular version. A subgroup of fifty-four patients (fifty-nine hips) underwent noncontrast magnetic resonance imaging of the hip an average of eight years after disease onset. The acetabular labrum was evaluated according to a modified classification system, and the acetabular cartilage was evaluated for the presence of delamination and defects. The association among abnormalities of the acetabular labrum, articular cartilage, and radiographic deformities was assessed.

RESULTS

Abnormalities of the acetabular labrum and cartilage were found on magnetic resonance imaging scans in 75% and 47% of the hips, respectively. An alpha angle of ≥55° was the deformity most significantly associated with labral and cartilage abnormalities, followed by coxa brevis. Coxa magna and a higher greater trochanter showed a significant association with labral abnormalities only. Acetabular retroversion showed an increased risk for labral abnormalities when the alpha angle was normal. When deformities coexisted, the alpha angle showed the greatest relative risk for abnormality.

CONCLUSIONS

On the basis of magnetic resonance imaging evaluation of the hip, labral and cartilage abnormalities were a common finding in patients with healed Legg-Calvé-Perthes disease. Our results suggest that hip deformities are significantly associated with labral and cartilage abnormalities on magnetic resonance imaging, and the main predisposing factor was the asphericity of the femoral head with a reduced femoral head-neck offset.

Joint-preserving surgery improves pain, range of motion, and abductor strength after Legg-Calvé-Perthes disease

BACKGROUND

Patients after Legg-Calvé-Perthes disease (LCPD) often develop pain, impaired ROM, abductor weakness, and progression of osteoarthritis (OA) in early adulthood. Based on intraoperative observations during surgical hip dislocation, we established an algorithm for more detailed characterization of the underlying pathomorphologies with a proposed joint-preserving surgical treatment.

QUESTIONS/PURPOSES

We asked if patients after LCPD treated with our algorithm experienced (1) reduced pain; (2) improved hip function; and/or (3) prevention of OA progression; we then determined (4) the intraoperative damage patterns; (5) the survival of the hip; and (6) factors predicting the need for a conversion to THA; radiographic progression of OA; a Merle d'Aubigné-Postel score below 15 at last followup; and/or the need for revision surgery.

METHODS

We retrospectively reviewed 53 patients after LCPD who underwent joint-preserving surgery (40 surgical hip dislocations, eight acetabular osteotomies, four combined procedures, and one intertrochanteric osteotomy). We obtained Merle d'Aubigné-Postel scores to assess pain; OA was assessed using Tönnis grades. Survival and predictive factors were calculated with the univariate Cox regression. Fifty of the 53 patients were evaluated at a minimum of 5.1 years (mean, 8.2 years; range, 5.1-12.8 years).

RESULTS

Pain and hip function improved at followup from a median of 4 points to 5 points. The mean increase in Tönnis grades at last followup was 0.3 to 0.8. The survival of surgery at 5 years was 86%; 13 factors related to survival.

CONCLUSION

Patients with symptoms resulting from pathomorphologic deformities after LCPD benefit from joint-preserving surgery with specific treatment of individual structural abnormalities.

A prospective multicenter study of Legg-Calvé-Perthes disease: functional and radiographic outcomes of nonoperative treatment at a mean follow-up of twenty years

BACKGROUND

Long-term studies have indicated good outcomes for most patients with Legg-Calvé-Perthes disease. However, clinical experience suggests that less favorable outcomes are common. We sought to prospectively document pain and function in a cohort of adults who had previously been treated nonoperatively for Legg-Calvé-Perthes disease.

METHODS

Patients in our region with Legg-Calvé-Perthes disease were enrolled between 1984 and 1991 as part of a multicenter prospective trial and were treated with hip range-of-motion exercises or bracing. Patients returned for physical examination, radiographs, and completion of outcome measures including the Nonarthritic Hip Score (NAHS) and the Iowa Hip Score (IHS).

RESULTS

Fifty-six patients (fifty-eight hips) were examined at a mean of 20.4 years (range, 16.3 to 24.5 years) after enrollment. The mean NAHS was 79 (range, 35 to 100), and the mean IHS was 74 (range, 43 to 100). Three patients had required hip arthroplasty and one patient had required a pelvic osteotomy. Fourteen (26%) of the remaining hips had no hip osteoarthritis, sixteen (30%) had mild osteoarthritis (Tönnis grade 1), and twenty-four (44%) had moderate or severe osteoarthritic changes on radiographs (grade 2 or 3). Femoroacetabular impingement indicated by physical examination was associated with pain and with poorer outcomes on the IHS and the NAHS (p = 0.0004, 0.0014, and 0.0007, respectively). The Stulberg classification was significantly associated with impingement on physical examination (p = 0.0495), the NAHS (p = 0.003), and the Tönnis grade (p = 0.012). Multivariate logistic regression showed that only the Stulberg classification was significantly associated with the NAHS (p = 0.0032); the odds ratio for a Stulberg type of I or II compared with IV or V in patients with a fair or poor NAHS was 0.101 (95% confidence interval, 0.018 to 0.573).

CONCLUSIONS

Pain, arthritis, and ongoing hip dysfunction are common in patients with Legg-Calvé-Perthes disease that was treated nonoperatively. Hips rated as Stulberg type III or IV more frequently had poor or fair outcomes on the IHS and NAHS (61% and 72% for type III and 77% and 60% for type IV). Patients with a lateral pillar type of B, B/C, or C frequently had pain and radiographic evidence of osteoarthritis. Clinical signs of femoroacetabular impingement were associated with pain and with lower functional scores. This prospective study establishes a modern benchmark for outcomes following nonoperative, weight-bearing treatment of Legg-Calvé-Perthes disease.