Objective

To determine the characteristics of femoral condyle insufficiency fracture (FCIF) lesions and their relative associations with the risk of clinical progression.

Materials and methods

This HIPAA-compliant retrospective study was approved by our Institutional Review Board. Seventy-three patients (age range, 19-95) were included after excluding patients with post-traumatic fractures, bone marrow infarct, osteochondritis dissecans, or underlying tumor. Two board-certified musculoskeletal radiologists classified morphologic findings including lesion diameter, associated bone marrow edema pattern, and associated cartilage/meniscus damage. Electronic medical charts were evaluated for symptoms, risk factors, and longitudinal outcomes, including total knee arthroplasty (TKA). Imaging characteristics were correlated with clinical findings, and comparison of outcome groups was performed using a regression model adjusted for age.

Results

The majority of patients with FCIF were women (64.4%, 47/73), on average 10 years older than men (66.28 ± 15.86 years vs. 56.54 ± 10.39 years, p = 0.005). The most common location for FCIF was the central weight-bearing surface of the medial femoral condyle; overlying full thickness cartilage loss (75.7%, 53/70) and ipsilateral meniscal injury (94.1%, 64/68) were frequently associated. Clinical outcomes were variable, with 23.9% (11/46) requiring TKA. Cartilage WORMS score, adjacent cartilage loss, and contralateral meniscal injury, in addition to decreased knee range of motion at presentation, were significantly associated with progression to TKA (p < 0.05).

Conclusions

FCIF are frequently associated with overlying cartilage loss and ipsilateral meniscal injury. The extent of cartilage loss and meniscal damage, in addition to loss of knee range of motion at the time of presentation, are significantly associated with clinical progression.

Objectives

To characterize the morphology and imaging findings of femoral head subchondral insufficiency fractures (SIF), and to investigate clinical outcomes in relation to imaging findings.

Methods

Fifty-one patients with hip/pelvis magnetic resonance (MR) images and typical SIF characteristics were identified and reviewed by two radiologists. Thirty-five patients had follow-up documentation allowing assessment of clinical outcome. Subgroup comparisons were performed using regression models adjusted for age and body mass index.

Results

SIF were frequently associated with cartilage loss (35/47, 74.5 %), effusion (33/42, 78.6 %), synovitis (29/44, 66 %), and bone marrow oedema pattern (BMEP) (average cross-sectional area 885.7 ± 730.2 mm(2)). Total hip arthroplasty (THA) was required in 16/35 patients, at an average of 6 months post-MRI. Compared to the THA cohort, the non-THA group had significantly (p < 0.05) smaller overlying cartilage defect size (10 mm vs. 29 mm), smaller band length ratio and fracture diameters, and greater incidence of parallel fracture morphology (p < 0.05). Male gender and increased age were significantly associated with progression, p < 0.05.

Conclusions

SIF were associated with synovitis, cartilage loss, effusion, and BMEP. Male gender and increased age had a significant association with progression to THA, as did band length ratio, fracture diameter, cartilage defect size, and fracture deformity/morphology.

Key points

• Femoral head subchondral insufficiency fractures (SIF) frequently require total hip arthroplasty (THA). • SIF frequently coexist with synovitis, cartilage loss, and bone marrow oedema pattern. • SIF cartilage defect size, band length ratio, and fracture diameter/morphology can predict progression risk.