Case 1. In 1981, an eleven-year-old Hispanic male without a relevant medical or surgical history presented after eighteen months of worsening pain in the lateral part of the left hip; the pain radiated to the knee and was aggravated by running. The patient did not report antecedent trauma, fevers, chills, or earlier symptoms. He did not report morning stiffness or other joint complaints. The family history was notable in that a great-grandfather reportedly had "hip problems" but was otherwise healthy.
On examination, the patient was in the seventy-fifth percentile for weight and the fortieth percentile for height. There was decreased motion of the left hip, most marked in rotation and abduction (flexion, 100°; extension, -10°; abduction, 30°; internal rotation, 0°; and external rotation, 10°). Anterior groin pain was elicited with internal and external rotation maneuvers, and lateral hip pain was reported with extremes of flexion.
Laboratory results demonstrated a normal hemoglobin level (133 g/L) and white blood-cell count (5.4 × 109 cells/L). Anteroposterior radiographs of the pelvis in the neutral and frog-leg lateral positions demonstrated a femoral head osteochondritic lesion bilaterally (Fig. 1, A, B, and C). Radiographs of the knee and spine demonstrated no abnormalities.
The patient was managed with bilateral lower extremity skin traction for one week, after which he underwent a hip arthrogram and then a percutaneous adductor tenotomy and Petrie cast application. The arthrogram of the left hip demonstrated a smooth articular rim with no evidence of chondral irregularity. The cast was removed after six weeks, and active motion exercises were begun. The patient reported decreased pain but had a persistent limp. Abduction remained limited to 25°. Radiographs that were made immediately after treatment revealed no changes in the appearance of the lesion in either hip in comparison with the pretreatment radiographs.
The patient returned twenty-seven years later with bilateral hip pain and was evaluated for hip arthroplasty. Examination at that time demonstrated limited and painful internal rotation of both hips. Radiographs revealed bilateral osteoarthritis of the hip with osteochondritis dissecans lesions of both femoral heads (Fig. 1, D).
Case 2. In 2002, the patient described above (Case 1) brought his otherwise healthy and developmentally normal three-year-old son for an evaluation of right hip pain. The father had noticed that his son had had a mild limp since the child had begun walking at twelve months of age; there was no history of hip trauma or infection. The child complained of hip pain that was temporarily relieved with ibuprofen, but he reported no night pain.
Physical examination of the child was unremarkable except for obesity, with the patient being in the ninety-fifth percentile for weight and the seventy-fifth percentile for height. The hips demonstrated a full, painless passive range of motion. A radiograph showing the pelvis and the lower extremities, made with the patient standing, revealed subtle, irregular epiphyseal contours in the right femoral head, without evidence of acetabular dysplasia or gross osseous abnormality (Fig. 2, A).
The child was followed for five years and returned at the age of nine years with worsening left groin pain that limited his activity. He had pain after walking long distances or running short distances. On examination, the left hip had painful, limited internal rotation of 20°. Standing anteroposterior and frog-leg lateral pelvic radiographs as well as magnetic resonance images were made, without arthrography (Fig. 2, B, C, and D). These studies identified an osteochondritis dissecans lesion of the femoral head bilaterally, with the lesion on the left being larger than the one on the right and with likely separation of the left osteochondritis dissecans lesion from the femoral head.
The patient underwent surgical dislocation of the left hip, which revealed an intact cartilaginous surface without any obvious areas of subchondral weakness. Given the proximity of the lesion to the fovea, microfracture was performed by passing a 2-mm drill through the fovea to the osteochondritis dissecans lesion.
At six months of follow-up, the patient reported excellent pain relief and demonstrated improved left hip range of motion. Radiographs revealed no change in comparison with the pretreatment appearance of the lesion (Fig. 2, E).
Case 3. In December 1999, an otherwise healthy nine-year-old boy, the nephew of one of the patients described above (Case 1) and the first cousin of the other patient described above (Case 2), presented with a presumed diagnosis of bilateral Legg-Calvé-Perthes disease. He had a two-year history of bilateral hip pain with activity, with the right hip being more painful than the left. The symptoms were temporarily relieved with rest and ibuprofen.
Examination revealed a right antalgic gait and limited hip motion bilaterally (flexion, 80° bilaterally; abduction, 35° on the right and 45° on the left). Anteroposterior and frog-leg lateral pelvic radiographs demonstrated bilateral femoral head osteochondritis dissecans lesions (Fig. 3, A).
The patient was managed symptomatically over four years and noted that the left hip pain decreased while the right hip pain worsened. At the age of thirteen years, he returned with substantial functional limitations due to the right hip pain. There was limited passive motion of the right hip and pain with internal rotation (flexion, 100°; abduction, 20°; adduction, 0°; external rotation, 30°; and internal rotation, 0°). Radiographs demonstrated a large osteochondritis dissecans lesion of the femoral head with abnormal acetabular morphology that was difficult to fully characterize but was thought not to be amenable to acetabular reorientation surgery. A magnetic resonance imaging arthrogram demonstrated an unstable osteochondral flap with contrast medium tracking below the femoral head lesion and with fissuring of the anterolateral acetabular labrum (Fig. 3, B and C).
The patient underwent surgical dislocation of the right hip with débridement of the osteochondral fragment base. The base of the lesion was drilled and grafted with bone obtained from the greater trochanter. The osteochondral flap was stabilized with three bioabsorbable pins (OrthoSorb; DePuy, Warsaw, Indiana) (Fig. 4), and capsular closure was performed.
Three months following surgery, the child continued to experience right hip pain and radiographs demonstrated subluxation of the hip with displacement of the osteochondral fragment (Fig. 3, D). Therefore, the patient underwent repeat surgical dislocation of the right hip with débridement of the osteochondral fragment, right hip capsulorrhaphy, and application of a pelvic-femoral Ilizarov joint-distraction frame to stabilize the hip (Fig. 3, E). The frame initially was static but was modified after one month to allow hip flexion, and it was removed after two months. Eighteen months after the application of the Ilizarov frame, and after a course of motion therapy, the patient had occasional, mild pain with a Trendelenburg limp on the right side and limited hip motion bilaterally. Radiographs continued to show subluxation of the right hip; however, the patient had excellent function overall and was able to participate in sports.
At the age of sixteen years, the patient returned with increasing, activity-related pain localized to the anterior part of the left hip. A magnetic resonance imaging arthrogram of the left hip revealed a large femoral head osteochondral lesion in association with anterior and posterior labral tears and femoral head chondromalacia. The patient underwent surgical dislocation of the left hip with débridement and excision of the osteochondral base, anterior and lateral acetabular roof trimming, repair of the torn labrum, and a femoral neck osteoplasty. Follow-up at six months showed a substantial decrease in the activity-related left hip pain (Fig. 3, F).
Pedigree Analysis
A detailed family history of hip pain was provided by the patients described above and is depicted in the pedigree diagram (Fig. 5). The father (Case 4) of the first patient (Case 1) had bilateral hip and knee pain for many years and ultimately underwent bilateral total knee replacement. The only radiographs of the hip, made at the age of fifty-nine years, demonstrated osteoarthritis and femoral head irregularity bilaterally (Fig. 6). Close examination of these radiographs revealed a "pointed" perifoveal head deformity bilaterally and a large, radiolucent area in the left femoral head, closely resembling the radiographic appearance of his son's hip in adulthood.
We were unable to find any reports of isolated bilateral idiopathic osteochondritis dissecans lesions of the femoral head with an apparent familial linkage in a literature review encompassing fifty-seven years. Numerous authors have reported on osteochondritis dissecans lesions of the femoral head in children, but most of those patients had associated diagnoses such as Legg-Calvé-Perthes disease or a history of antecedent trauma3-6. Reports of a presumably idiopathic osteochondritis dissecans lesion in the pediatric population are scarce, and the lesions are always unilateral7-10. Furthermore, although a genetic linkage for osteochondritis dissecans has been identified in the distal part of the femur and the distal part of the humerus, we could find no similar reports concerning the femoral head in the literature11-14.
Many diagnoses may mimic or yield osteochondritis dissecans lesions in the femoral head, the most common of which is Legg-Calvé-Perthes disease. More obscure diagnoses are hereditary dysplasias, including multiple epiphyseal dysplasia, dysplasia epiphysealis capitis femoris (Meyer dysplasia), and bilateral hereditary microepiphyseal dysplasia of the hip15-18. In the case series presented, no patient had prior or subsequent changes consistent with the various stages of fragmentation and remodeling seen in Legg-Calvé-Perthes disease. Furthermore, the epiphyseal dysplasias discussed typically exhibit epiphyseal abnormalities at multiple sites. The patients in the present report demonstrated no involvement of other joints in the lower extremity, and all subjects were of normal stature.
The pedigree analysis of this family does not suggest a specific mode of transmission and is limited by the small number of affected individuals. However, an X-linked inheritance pattern may be excluded given the male-to-male transmission found in the patients presented. An autosomal transmission is possible and may be similar to the autosomal dominant inheritance reported for familial osteochondritis dissecans in the distal part of the femur and the distal part of the humerus13,19. Interestingly, a Y-linked transmission is feasible if examining only patients with both radiographic and clinical evidence of bilateral femoral head osteochondritis dissecans lesions but is statistically unlikely when considering the paucity of genes on the Y chromosome. More refined molecular genetic analysis of this family will be the subject of future research.
The time of symptom onset for bilateral femoral head osteochondritis dissecans appears to be variable and may occur from infancy to adolescence, but functional impairment appears to occur uniformly during adolescence. No specific treatment plan is advocated in the present report, given the short duration of follow-up and the variability of methods applied. We cannot verify that the procedures that we performed had any substantial impact on the natural history of the disease. Previous reports with short-term follow-up have suggested that excision of the osteochondritis dissecans fragment is successful in relieving mechanical hip symptoms in 85% of cases but that only 50% of the patients have relief of pain2,7. In the present study, magnetic resonance imaging arthrography was most useful for assessing the stability of the fragment as it seemed to best correlate with the appearance of the osteochondritis dissecans lesion at the time of surgical dislocation. In the case of the second patient (Case 2), a magnetic resonance imaging study without an arthrogram component suggested a loose osteochondral fragment, but examination of the femoral head at the time of surgical hip dislocation identified an intact cartilaginous surface. In contrast, the magnetic resonance imaging arthrogram in the case of the third patient (Case 3) clearly demonstrated a displaced and unstable osteochondritis dissecans lesion that was confirmed at the time of surgery.
In the third patient (Case 3), the etiology of hip instability following the initial surgical dislocation and repair of the osteochondritis dissecans fragment is unclear. Displacement of the osteochondritis dissecans fragment by itself may not have resulted in the subsequent hip subluxation without the preexisting abnormal acetabular morphology and a surgical dislocation approach that likely upset a marginally stable joint. In retrospect, an acetabular reorientation procedure to provide better femoral head coverage may have been useful in the case of this patient and may have prevented the need for further surgical treatment.
The importance of recognizing a familial pattern to osteochondral lesions rests in the observation that such patients may be more predisposed to early arthritis. Linden followed seventy-six knee joints with sporadic, idiopathic distal femoral osteochondritis dissecans lesions for an average of thirty-three years and noted that, of twenty-three joints diagnosed with osteochondritis dissecans before physeal closure, only two had development of degenerative arthritis in adulthood20. In contrast, Stougaard reported that four of eight members of a family with osteochondritis dissecans lesions of the distal part of the femur demonstrated degenerative changes of the knee14. Fonseca et al. noted that three family members with distal femoral osteochondritis dissecans all had development of subsequent degenerative knee changes at an average of twenty-two years of follow-up, with or without surgical intervention12.
The cases of familial, bilateral femoral head osteochondritis dissecans presented here are a caricature of disease progression, from intermittent symptoms at a young age, to functional limitations by adolescence, and, ultimately, to degenerative changes of the hips in early adulthood. As this is a small case series with a short duration of follow-up, specific treatment recommendations cannot be provided. However, a few important points have been gleaned from these patients. First, a magnetic resonance imaging arthrogram appears to be the best imaging study to define the stability of the femoral head osteochondritis dissecans lesion when planning surgical treatment. Second, drilling of a stable lesion to stimulate healing or excision of an unstable lesion appears to reduce symptoms in the short term. Finally, a genetic link must be considered when evaluating patients with bilateral femoral head osteochondritis dissecans lesions as the prognosis appears to be poor and the information may allow an opportunity for genetic screening and counseling in the future. 