Lustıg, Sébastien

Substantial healthcare resources have been devoted to computer navigation and patient-specific instrumentation systems that improve the reproducibility with which neutral mechanical alignment can be achieved following total knee replacement (TKR). This choice of alignment is based on the long-held tenet that the alignment of the limb post-operatively should be within 3° of a neutral mechanical axis. Several recent studies have demonstrated no significant difference in survivorship when comparing well aligned versus malaligned TKRs. Our aim was to review the anatomical alignment of the knee, the historical and contemporary data on a neutral mechanical axis in TKR, and the feasibility of kinematically-aligned TKRs. Review of the literature suggests that a neutral mechanical axis remains the optimal guide to alignment. Cite this article: Bone Joint J 2014;96-B:857–62.

AbstractPurposePatellofemoral arthroplasty remains controversial, primarily due to the high failure rates reported with early implants. Numerous case series have been published over the years detailing results of various first‐ and second‐generation implants. The purpose of this work is to summarize results published to date and identify common themes regarding implants, surgical techniques, and indications in order to maximize results of future procedures.MethodsA comprehensive review of the MEDLINE database was carried out to identify all clinical studies related to patellofemoral arthroplasty.ResultsFirst‐generation resurfacing implants were associated with relatively high failure rates in the medium term. Second‐generation implants, with femoral cuts based on TKA designs have yielded more promising medium‐term results. Surgical indications are specific and must be carefully followed to minimize poor results. Short‐term complications are generally related to patellar maltracking, while long‐term complications are generally related to progression of osteoarthritis in the tibiofemoral joint. Implant loosening and polyethylene wear are rarely reported. Short‐term results are favourable for new technology including custom implants and computer navigated surgery.ConclusionsOverall, recent improvements in implant design and surgical techniques have resulted in improvements in short‐ and medium‐term results. More work is required to assess the long‐term outcomes of modern implant designs.Level of evidenceIV.