A two-degree-of-freedom hip exoskeleton device for an immature animal model of exercise-induced Legg—Calvé—Perthes disease

Legg-Calvé-Perthes disease overview

Background

Legg–Calvé–Perthes Disease (LCPD) is a necrosis of the femoral head which affects the range of motion of the hips. Its incidence is variable, ranging from 0.4/100,000 to 29.0/ 100,000 children. Although LCPD was first described in the beginning of the past century, limited is known about its etiology. Our objective is to describe the main areas of interest in Legg–Calve–Perthes disease.

Methods

A review of the literature regarding LCPD etiology was performed, considering the following inclusion criteria: Studies reporting clinical or preclinical results. The research group carried out a filtered search on the PubMed and Science Direct databases. To maximize the suitability of the search results, we combined the terms ‘‘Perthes disease” OR “LCPD” OR “children avascular femoral head necrosis” with “diagnostic” OR “treatment” OR “etiology” as either key words or MeSH terms.

Results

In this article been described some areas of interest in LCPD, we include topics such as: history, incidence, pathogenesis, diagnosis, treatment and possible etiology, since LCPD has an unknown etiology.

Conclusions

This review suggests that LCPD has a multifactorial etiology where environmental, metabolic and genetic agents could be involved.

Female patients with late-onset legg-calvé-perthes disease are frequently gymnasts: is there a mechanical etiology for this subset of patients?

BACKGROUND

The cause of Legg-Calvé-Perthes disease (LCPD) is unknown. We have observed a relatively high prevalence of female gymnasts presenting with LCPD. The purpose of this study was to determine: (1) the percentage of LCPD patients exposed to high-level gymnastics training, (2) the demographics of this subset of patients, and (3) their clinical outcomes.

METHODS

Several adolescent female gymnasts presented to our clinic with recent-onset LCPD. We reviewed our cases to discern the prevalence and treatment of the disorder in this patient cohort. From 1999 to 2010, 572 patients were evaluated for a diagnosis of LCPD at our tertiary referral center. Clinical records were retrospectively reviewed. Of those, 13 patients had a history of gymnastics participation with 8 patients (all females) having competitive participation.

RESULTS

For females aged 10 years and older presenting with LCPD, 7 of 9 patients (78%) were involved in high-level competitive gymnastics. These patients had disease onset between 10 and 12 years of age (mean, 11 y). Competitive gymnasts represented 6.6% (8 of 120) of females with LCPD and 1.4% (8 of 572) of all patients evaluated with LCPD during the study period. Only 1 of 111 females below 10 years with LCPD participated in competitive gymnastics (χ, P<0.0001).Patients underwent a variety of treatments. Two patients underwent nonoperative treatment, and the remainder underwent surgical management. All 7 gymnasts had a Stulberg IV result. In the nongymnast group of females 10 years and older, there were 1 Stulberg III result and 1 Stulberg IV result.

CONCLUSIONS

At our center, competitive gymnasts comprise >75% of the female patients over the age of 10 who presented with late-onset LCPD. Results in general were poor. Further studies are needed to explore the association between the physical demands of advanced gymnastic training and the development of LCPD in this subset of patients.

LEVEL OF EVIDENCE

IV, case series.

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

BACKGROUND

Acetabular retroversion has been identified in mature patients with sequelae of Legg-Calvé-Perthes (LCP) disease. Whether this is a contributing etiologic factor that leads to the disease process or result of the head deformity is not known. The prominence of the ischial spine (PRIS) sign, which reflects retroversion, can be observed before ossification of the anterior and posterior walls in a skeletally immature patient and could help determine whether the retroverted acetabulum is present before or after head involvement in patients with LCP disease.

QUESTIONS/PURPOSE

We therefore determined (1) the prevalence of the PRIS sign in patients with LCP disease compared with healthy control subjects, (2) whether the PRIS sign is seen at the time of head involvement in patients with LCP disease, and (3) the prevalence of bilaterality of the PRIS sign in patients with LCP disease and control subjects.

PATIENTS AND METHODS

Of 295 patients with LCP disease, 47 (49 hips) met our inclusion criteria. Of these, 39 (41 hips) had open triradiate cartilage and comprised the study group. Twenty-five pediatric patients with polytrauma (50 hips) with standardized radiographs comprised the control group.

RESULTS

A positive PRIS sign was noted in 37 of the 41 skeletally immature hips compared with only 16 of the 50 control hips. We observed a positive PRIS sign early in the LCP disease process with eight of nine patients in the fragmentation phase having a positive PRIS sign. The PRIS sign was seen bilaterally in 25 of 39 patients with unilateral LCP disease and in only five of 25 control patients.

CONCLUSIONS

Acetabular retroversion, as evidenced by a positive PRIS, was present in nine of 10 children with LCP disease. It is uncertain if retroversion is a cause or a sequela of the disease, but it was seen early in the disease process at the time of head involvement in the majority of patients.

LEVEL OF EVIDENCE

Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.