Bilateral subchondral insufficiency fractures of the femoral head in a normally active adolescent patient: A case report

A case of osteogenesis imperfecta diagnosed after subchondral insufficiency fracture of bilateral femoral heads

Osteogenesis imperfecta (OI) is a heterogeneous disorder characterised by bone fragility. Herein, we report a case of OI diagnosed after subchondral insufficiency fracture (SIF) of bilateral femoral heads. A 37-year-old woman was referred to Saitama Medical University Hospital due to left hip pain without any trauma that lasted for 2 months. She was subsequently diagnosed with SIF of the left femoral head. After 3 months, she further developed SIF of the right hip without any trauma. Magnetic resonance imaging of the bilateral hips showed linear low-signal changes of the subchondral bone and bone marrow oedema of the femoral head on T2-weighted coronal and sagittal images, diagnosing of both SIFs. The bone mineral density was 0.851 g/cm2 (T-score, -1.3) at the lumbar spine, 0.578 g/cm2 (T-score, -1.9) at the right femoral neck, and 0.582 g/cm2 (T-score, -1.9) at the left femoral neck. Considering that the patient had multiple histories of fracture, blue sclera, and mild bilateral sensorineural hearing loss, she satisfied the diagnostic criteria for OI. Genetic testing revealed a mutation in COL1A1 (NM_000088.3, c.3806G>A: p. Trp1269*). After 7 months of conservative therapy, her symptoms improved. After 4 years, both hips were pain-free with no evidence of osteoarthritis progression. OI can result in insufficiency fractures due to bone fragility in adolescence and adulthood or later, and none of the cases of OI, except for the current case, were diagnosed as a result of bilateral SIF.

Predictors of cartilage degeneration in patients with subchondral insufficiency fracture of the femoral head: a retrospective study

Background

There is evidence that the cause of primary osteoarthritis (OA) is related to the changes in subchondral bone; however, the influence of subchondral insufficiency fracture (SIF) of the femoral head on the degeneration of the hip joint and the prognostic factors related to joint degeneration remain unclear. The objectives of this study were (1) to investigate the natural history of joint space width after the occurrence of SIF and (2) to investigate the associations between joint space narrowing and bone metabolic markers as well as magnetic resonance imaging (MRI) among the patients with SIF.

Methods

Between January 2010 and December 2019, 238 patients in whom band pattern of the femoral head were observed on MRI visited Hokkaido University Hospital. Among these patients, 44 hips in 41 patients were diagnosed with SIF and eligible for this retrospective study. We evaluated the joint space width (JSW) of the hip on the radiograph obtained at the first and last visits, length of the band lesion on MRI, bone mineral density by dual-energy X-ray absorptiometry, and bone metabolism markers. Similarly, the factors associated with the necessity of surgery and the progression of the narrowing of the joint space were evaluated.

Results

Fifteen of the 44 hips required total hip arthroplasty (THA). A significant decrease was observed in the JSW from the first visit to the final follow-up. Changes in the JSW were associated with the length of band patterns, serum type 1 procollagen-N-propeptide (P1NP), and tartrate-resistant acid phosphatase 5b (TRACP-5b) during diagnosis. Additionally, bone metabolic markers tended to be associated with the length of the band pattern.

Conclusions

SIF could cause joint space narrowing and hip OA. In addition to MRI findings as prognostic predictors of SIF, as previously described, bone metabolic markers were equally associated with changes in JSW, suggesting that these parameters could be useful in predicting the prognosis of SIF. Considering that bone metabolic markers trended to be associated with the length of band pattern, they might reflect the local severity.