Introduction: Screw loosening is a common complication of osteoporotic fracture fixation leading to implant loosening, fracture malunion and non-union. Because recent animal studies have shown that bisphosphonates improve implant fixation we wanted to assess whether alendronate (ALN) improves screw fixation in a clinical setting of osteoporotic fractures.

Methods: Sixteen consecutive patients with AO/OTA A1 pertrochanteric fractures were selected. Inclusion criteria were: female over the age of 65, BMD T-score less than −2.5 SD. Fractures were fixed with a pertrochanteric fixator and 4 hydroxyapatite (HA)-coated screws. Two screws were implanted in the femoral head (screw positions 1 and 2) and two in the femoral diaphysis (screw positions 3 and 4). Patients were randomized to either postoperative systemic administration of ALN, 70 mg per week for 3 months (Group A) or no ALN. Fixators were removed at 3 months post-op in all patients.

Results: All the fractures healed. No differences in screw insertion torque between the two groups were found. No pin loosening or infection occurred. The combined mean extraction torque of the screws implanted at positions 1 and 2 (cancellous bone) was 3181 ± 1385 N/mm in Group A and 1890 ± 813 N/mm in Group B (p < 0.001). The combined mean extraction torque of the screws implanted at positions 3 and 4 (cortical bone) was 4327 ± 1720 N/mm in Group A and 3785 ± 1181 N/mm in Group B (ns).

Discussion and Conclusion: This is the first study to demonstrate in a clinical setting improved screw fixation following post-operative ALN treatment. We observed a two-fold fixation increase in the screws implanted in cancellous bone. With cortical bone, the difference in screw fixation was less marked. Besides its bone preserving ALN should be recommended as an effective solution to improve fixation in osteoporotic bone.

INTRODUCTION: This prospective randomized study investigated short-term outcomes of cemented vs. HA-coated hip arthroplasty in elderly osteoporotic patients with femoral neck fractures.

METHODS: Forty consecutive patients with femoral neck fractures (AO/OTA fracture type B2 and B3) were randomized to receive either an AHS prosthesis (Group A, n = 22, cemented implant) or a Furlong prosthesis (Group B, n = 18, HA-coated implant). Inclusion criteria were: female age ≥75, fracture resulting from minor trauma, ability to communicate and bone mineral density (BMD) T-score at the contralateral hip lower than −2.5 SD. Subjective assessment was evaluated according to a rating system 0-(unsatisfactory) to 10(satisfactory). Average follow-up was 29 months for Group A and 27 months for Group B.

RESULTS: Average patient age was 75 ± 5 in both groups. There were no differences in ASA scores between the two groups. Surgical time was 77 ± 12 minutes for Group A, and 72 ± 13 minutes for Group B (ns). Harris hip score was 46 ± 36 in Group A and 62 ± 33 in Group B. (p < 0.05). SF-36 was 35 ± 32 in Group A and 54 ± 32 in Group B (ns). Subjective assessment was 5 ± 4 in Group A and 7 ± 3 in Group B (ns). The incidence of death during the follow-up period was 33% in Group A and 15% in Group B. (p < 0.05). One Group A patient underwent revision due to implant loosening. A Furlong prosthesis was successfully implanted in this patient.

DISCUSSION: Although femoral neck fractures in elderly osteoporotic patients are usually treated with cemented arthroplasty, our comparative study showed better results with the Furlong prosthesis, even if statistical significance was reached in only two parameters. The outcomes obtained with the Furlong prosthesis are due to the ability of the HA-coating to bind with osteoporotic bone, thus establishing a stable fixation. Fixation failed in only one cemented implant, but our case number was limited and the follow-up short. Post-op mortality at the time of follow-up was high. This was not unexpected, given the age level and health status of the study groups. This study shows that the HA-coated Furlong prosthesis is a viable option for the treatment of elderly osteoporotic femoral neck fracture patients.