Patellar button compatibility in the conversion of Patellofemoral Arthroplasty to a Total Knee Arthroplasty: A review of the contemporary literature.

BACKGROUND: Compared to total knee arthroplasty (TKA), patellofemoral arthroplasty (PFA) is a far less commonly performed operation. However, in carefully selected cohorts, PFA continues to be an appropriate treatment option for end-stage isolated patellofemoral joint osteoarthritis. In the later situation whereby a PFA is considered for conversion to a TKA - often due to disease progression - uncertainty remains regarding optimal management of the in situ patellar button. This review of the contemporary literature aimed to provide a summary of the current evidence to support surgeon decision-making, by evaluating the compatibility, efficacy, and survivorship of retained versus revised patellar buttons in PFA-to-TKA conversion. Specific focus was paid to implant design and technical considerations during revision, plus post-operative patient-reported outcomes and modes of secondary patellar component failure. METHODS: A review of the Embase, Cochrane and PubMed databases was performed following PRISMA search principles. RESULTS: This investigation highlights that the fate of patellar buttons in PFA-to-TKA conversion has previously been poorly studied, with scant publication data available. Most reports have been of singular cases or small cohort series. Larger formal RCTs and level 1 evidence are lacking. CONCLUSION: The findings herein suggest that surgeons can confidently retain well-fixed, undamaged, dome-shaped all-polyethylene patellar buttons in the conversion of a PFA to TKA with the expectation of acceptable mid-term performance and survivorship, as long as congruent tracking with the new tibiofemoral components is achieved. This result is likely translatable to the majority of contemporary, all-polyethylene, dome-shaped patellar buttons, even with manufacturer mismatch.

The use of the ligament augmentation and reconstruction system for posterior cruciate ligament reconstruction in isolated and multiligament knee injuries: A systematic review.

PURPOSE: To evaluate the efficacy and safety of the Ligament Augmentation and Reconstruction System (LARS) in posterior cruciate ligament (PCL) reconstruction in isolated PCL injuries and multiligament knee injuries, analysing clinical, radiographic, and patient reported outcome measures (PROMs). METHODS: A systematic review according to PRISMA guidelines was performed through Embase via Ovid, PubMed, and the Cochrane Library to identify studies reviewing LARS use for PCL reconstruction. The methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. RESULTS: From 225 results screened, 13 studies were included published between 2004 and 2020, analysing LARS use for PCL reconstruction. Mean follow-up was 21 months to 11.9 years, however only four studies had follow-up of over five years. Results in isolated PCL reconstruction utilising LARS demonstrated scores that were consistent with good function and minimal limitation in daily or sporting activities, in addition to a significant improvement in knee laxity and low complication rates. Symptomatic rupture and synovitis rates were both 1.7% in this group. LARS use in complex multiligament injuries demonstrated satisfactory PROMs, although there was concern regarding residual laxity on stress radiography. CONCLUSIONS: LARS demonstrates good outcomes in PCL injury reconstruction in the short to mid-term, particularly in isolated PCL injuries, achieving equivocal or improved results compared to autograft reconstruction using hamstring tendon in the three comparative studies included. LARS has a quicker recovery time and no donor-site morbidity, however long-term data is lacking. Utilising LARS for reconstruction of the PCL in multiligament injuries revealed more variable results.