Locking strategies of the sliding screw in gamma nailing (G3) were tested in an experimental biomechanical study.

Twelve Composite Femoral Bone models were used. An intertrochanteric osteotomy was performed and a gamma nail was implanted in each specimen. The specimens were divided in 3 groups:

compressed and locked,

Subsequently, the specimens were investigated for cut-out patterns using digital photography and management.

All failures occurred under supraphysiological loads. During their first loading cycles, no statistical differences for stiffness and yield load were noted. Nevertheless, there was a non–significant tendency for higher failure loads for the unlocked group. Under maximum load (1100 N) and already established deformations, all Gamma Nails behaved similarly in terms of neck-screw displacement, with no statistical differences.

Unlocked screws exhibited the most moderate failure modes followed by the compressed and locked group. The third group showed the most severe failures.

In conclusion, there is evidence that sliding is biomechanically superior in gamma nailing. Despite adverse mechanical circumstances all specimens behaved satisfactorily under physiological loading

Introduction: The operative treatment of intra- and supracondylar fractures presents a challenging problem for the orthopaedic surgeon, since their morphology may jeopardize fracture ‘s stability and patients’ early mobilization. The use of retrograde inserted intramedullary femoral nails seems to be offering solutions to these problems.

Material-methods: 13 patients have been included in the study, 11 females and 2 male. The mean age was 49.4 years (range 23 to 82). There was no open fracture and the injury had resulted mainly in long, oblique supracondylar fractures, with the exception of one case where an intracondylar component of the fracture was present combined with a fractured patella. Surgical intervention was performed within 5–12 days post-injury, for that reason all patient required a form of open reduction. Long nail fixation without proximal screw locking was performed in 3 cases. Plaster splint immobilization for 6 weeks was applied in two cases, the one with the intracondylar component and fractured patella and the more aged patient who suffered from dementia. Early mobilization was instructed in all other patients with progressive weight load bearing in correlation to the radiological appearance of fracture healing.

Results: Fracture healing was obtained in all cases within the expected time period, varying from 18 to 38 weeks No infections or VTE was noted. Patients’ mobilization had been early (dictated by patients’ collaboration and/or presence of coexisting injuries). Adverse reactions include quadriceps muscle wasting combined with some degree of extension lag (50% of cases). No adverse events related to the use of long nails without proximal screw locking have yet been detected.

Conclusion: Intramedullary retrograde nail fixation in supra- and intracondylar fractures of the lower end of the femur seems to be a relatively simple operative procedure, inducing functional outcome and patients satisfaction. Delayed callus formation and muscular wasting that was noted in some patients can be attributed to the open reduction technique.