Late Periprosthetic Femoral Stress Fracture Associated with Extra-articular Deformity in a Patient with Fibrous Dysplasia: A Case Report.

CASE: In the setting of a total hip arthroplasty performed in a patient with a proximal femoral deformity, atraumatic periprosthetic femoral stress fracture may arise as a complication. We report a rare case of a late periprosthetic femoral stress fracture around a cemented stem in a patient with a history of fibrous dysplasia of the proximal femur. After a 10-year uneventful period, the patient complained about a subtle, subacute pain in his left thigh induced by exercise but not with daily axial load. Diagnosis of a nondisplaced, incomplete (i.e., only compromising the lateral femoral cortex) periprosthetic femoral stress fracture was made with plain radiographs, blood work, and bone scintigraphy. Surgical treatment consisted of a minimally invasive plate osteosynthesis bridging the femoral deformity plus percutaneous osteoperiosteal decortication. At 5-year follow-up, the patient was asymptomatic with full return to physical activity, with radiographs evidencing callus formation. CONCLUSION: Stress fractures around well-fixed femoral stems, while infrequent, should be addressed in patients with a history of severe proximal femur deformity experiencing atraumatic thigh pain.

Patients with trochanteric hip fractures and pre-existing osteoarthritis can be treated with nailing osteosynthesis without significant decrease in functional status.

PURPOSE: Functional outcome in patients after trochanteric fracture fixation with pre-existing radiographic osteoarthritis (OA) is unclear. Analyzing their function and independence, before and after fracture, could optimize their treatment and decrease the socioeconomic burden in this particular group. METHODS: The influence of pre-existing radiographic hip OA on functional outcome was retrospectively analyzed with a cohort of patients undergoing proximal femoral nailing for trochanteric fracture. OA was graded according to the Tonnis classification. Functional outcome was assessed preoperatively and 12 months after surgery by the Parker Mobility Score (PMS). We consider a meaningful reduction a difference between preoperatively PMS and 12 months after surgery ≥ 2. In order to evaluate if OA is related to PMS reduction ≥ 2, we calculate the SubHazard ratio (SHR) performing a competing risk regression model considering death as a competing risk event, adjusting by confounders. Death, reoperations, readmissions, surgical time, and fracture reduction quality in patients with and without osteoarthritis were recorded. RESULTS: 375 trochanteric hip fractures treated with cephalomedullary nails were included, from which 80 (21% CI95% 17%-21%) were classified as Tonnis 2 or 3. This group of patients with pre-existing OA was significantly older (mean age of 88.6 [SD 5.65] vs 85.5 years [SD 6.95]) than the group without OA. The preoperatively PMS score was 6.28 (2.71) in non-OA patients and 5.69 (2.67) in OA patients. The mean PMS reduction 12 months after surgery was 1.3 (SD 2.05) in OA patients and 1.07 (SD 2.2) in non-OA patients (p = 0.43). Competing risks analysis, adjusted by confounders had an SHR of 1.15 (IC95% 0.77 - 1.69). Death, readmission, reoperations, surgical time, and fracture reduction quality did not differ in both groups. CONCLUSIONS: Patients with pre-existing radiographic OA treated with femoral nailing have a similar reduction in functional outcomes compared to the non-OA group at one-year follow-up. Further studies will be needed to compare the results of the functional outcome in arthroplasty with those of femoral nailing for the treatment of trochanteric femur fractures in patients with OA.