Mechanically aligned total knee arthroplasty demonstrates acceptable outcomes in obese patients, with insufficient evidence for alternative alignment strategies: A systematic review.
systematic_review · Level I
Where this comes from
- Record sourced from PubMed, PMID 42534471.
- Also identified by DOI 10.1002/jeo2.70860 and PMC identifier 13420840.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Obesity (body mass index [BMI] ≥ 30 kg/m<sup>2</sup>) is increasingly prevalent among total knee arthroplasty (TKA) patients and is associated with unique challenges. The role of various TKA alignment strategies in obese patients remains unclear. To evaluate the clinical, functional, radiographic, survivorship and complication outcomes of primary TKA in obese patients across alignment philosophies. Eligible studies (1) included patients who underwent primary TKA with defined alignment, (2) reported BMI ≥ 30 kg/m<sup>2</sup> or provided stratified data for obese versus non-obese groups, (3) reported at least one of: patient-reported outcome measures (PROMs), range of motion (ROM), radiographic outcomes, or complications and (4) were randomized controlled trials (RCTs), cohort studies or case-control studies. Thirty studies were included. 8468 obese patients (14,662 knees) underwent mechanically aligned TKA, with mean follow-up of 91.1 ± 45.3 months (range, 0.5-110.5 months). Mechanically aligned TKA in obese patients was associated with post-operative improvements in PROMs, including Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index and Oxford Knee Score. Short-term cumulative aseptic revision incidence was low, ranging from 0.5% to 1.3%, while revision-free survivorship commonly exceeded 95% at short-term and >90% at long-term follow-up. Radiographic outcomes demonstrated reliable restoration of near-neutral limb alignment across BMI strata. One study evaluated a kinematically-designed bicruciate-stabilized implant with an unspecified alignment strategy in obese patients, and another study evaluated functional alignment in obese patients, limiting comparisons. Evidence evaluating the influence of alignment on outcomes in obese patients undergoing TKA remains insufficient to determine whether alignment philosophy meaningfully affects clinical or radiographic outcomes. Although mechanically aligned TKA demonstrated generally acceptable post-operative outcomes in obese cohorts, the available literature was overwhelmingly dominated by mechanically aligned studies, with only limited evaluation of alternative approaches. Level IV.