How to reduce osteopenia in total knee arthroplasty?

BACKGROUND: Osteopenia of the front half of the distal femur is a well-known problem after total knee arthroplasty (TKA) with secondary issues after years, especially when must be addressed fractures or revisions for loosening. Stress shielding has been recognized as a cause in different biomechanical studies of the bone.

QUESTION/PURPOSES: It was logical to look for a solution by changing the design to minimize stress shielding behind the femoral shield.

PATIENTS AND METHODS: It was proved that radiological measure of bone density was reliable although not so early and accurate as densitometry. We used a shield without posterior fixation of the trochlea in a series of 21 TKA with radiological measures, preoperative, at 3 months and at 5 years. We compared the results with those of a series of classical TKA in the same category of age and sex.

RESULTS: The TKA without trochlea posterior fixation presented a significantly reduced osteopenia compared to the classical design of the femoral shield.

CONCLUSION: It seems that the non-fixation of the posterior surface of the trochlea may reduce osteopenia in TKA and so the risk of fractures and complications when revision surgery.

LEVEL OF EVIDENCE: 2a.