Outcomes and early revision rate after medial unicompartmental knee arthroplasty: prospective results from a non-designer single surgeon

Abstract

BackgroundThis prospective study evaluates outcomes and reoperation rates for unicompartmental knee arthroplasty (UKA) from a single non-designer surgeon using relatively extended criteria of degenerative changes of grade 2 or above in either or both non-operated compartments.Methods187 consecutive medial mobile bearing UKA implants were included after history, clinical assessment and radiological evaluation. 91 patients had extended clinical outcomes. Post-operative assessment included functional scoring with the Oxford Knee Score (OKS) and radiographic review. Survivorship curves were constructed using the life-table method, with 95% confidence intervals calculated using Rothman’s equation. Separate endpoints were examined: revision for any reason and revision for confirmed loosening.ResultsThe mean follow-up was 3.5 years. The pre-operative OKS improved from a mean of 21.2 to 38.9 (Mann-Whitney U Test, p = < 0.001). Twelve Patients required further operations including 9 revisions. No patients developed deep infection and no surviving implants were loose radiographically. Survivorship at 7 years with endpoints of re-operation, revision and aseptic loosening at surgery or radiographically was 88.4% (95% CI 79.6–93.7), 93.1% (95% CI 85.5–96.9) and 97.3% (95% CI 91.2–99.2) respectively. The presence of pre-operative mild contralateral tibiofemoral or any extent of patellofemoral joint degeneration was of no consequence.DiscussionThe indications for UKA are being expanded to include patients with greater deformity, more advanced disease in the patellofemoral joint and even certain features in the lateral compartment indicative of an anteromedial pattern of osteoarthritis (OA). However, much of the supporting literature remains available only from designer centres. This study represents a group of patients with what we believe to be wider indications, along with decisions to treat made on clinical grounds and radiographs alone.ConclusionThis study shows comparable clinical outcomes of UKA for extended indications from a high volume, high-usage non-designer unit.Electronic supplementary materialThe online version of this article (10.1186/s12891-018-2099-2) contains supplementary material, which is available to authorized users.

A Case-Control Comparison of Single-Stage Bilateral vs Unilateral Medial Unicompartmental Knee Arthroplasty

“…Only Chan et al's study [9] found a higher number of distal deep vein thrombosis cases in bilaterally operated upon patients, but they did not benefit from postoperative drug thromboprophylaxis. No infectious complications were found in our study, which is also consistent with the literature [26,27].…”

Anterior Impingement After Mobile-Bearing Unicomparimental Knee Arthroplasty—A Neglected Problem. A Clinical Report of 14 Cases

“…Also, in other studies, osteoarthritis in the lateral joint compartment is the most common reason for the revision in MB-UKA [ 17 ]. An important implant-specific reason for revision is the mobile polyethylene inlay, which shows a 0.6%-3.4% dislocation risk [ 3 , 6 , 8 , 11 , [18] , [19] , [20] , [21] , [22] , [23] ].…”

High usage of medial unicompartmental knee arthroplasty negatively influences total knee arthroplasty revision rate

“…This has led to recommendations such as a 'minimum' surgeon UKA usage of 20% and an 'optimum' usage of 40-60% to minimize the risk of revision [19]. This increase in usage is supported by studies reporting similar clinical outcomes when using 'extended' UKA indications [8], accepting higher grade patellofemoral chondral change [13], or ignoring BMI [21].…”