Arthrofibrosis after total knee arthroplasty: patients with keloids at risk

BACKGROUND: Arthrofibrosis remains one of the leading causes for revision in primary total knee arthroplasty (TKA). Similar in nature to arthrofibrosis, hypertrophic scars and keloid formation are a result of excessive collagen formation. There is paucity in the literature on whether there is an association between keloid formation and the development of arthrofibrosis following TKA. Therefore, the purpose of this study was to utilize a large nationwide database to identify and compare the rates of postoperative complications related to arthrofibrosis after primary TKA in patients with history of hypertrophic scar and keloid disorders versus those without. METHODS: Patient records from 2010 to the second quarter of 2016 were queried from an administrative claims database, comparing rates of arthrofibrosis, manipulation under anesthesia (MUA), lysis of adhesions (LOA), and revision TKA in patients with chart diagnosis of keloids versus those without in patients who underwent primary TKA. Data analysis was performed using R statistical software (R Project for Statistical Computing, Vienna, Austria) utilizing multivariate logistic regression, chi square analysis, or Welch’s t- test where appropriate with p values < 0.05 being considered statistically significant. RESULTS: Of 545,875 primary TKAs, 11,461 (2.1%) had a keloid diagnosis at any time point in their record, while 534,414 (97.9%) had not. Patients in the keloid cohort had a significantly higher association with ankylosis within 30 days (OR, 1.7), 90 days (OR, 1.2), 6 months (OR, 1.2), and 1 year (OR, 1.3) following primary TKA. The keloid cohort also had a significantly greater risk of MUA (90-day OR, 1.1; 6-month OR, 1.1; 1-year OR, 1.2) and LOA (90-day OR, 2.2; 6-month OR, 2.0; 1-year OR, 1.9). CONCLUSION: Patients with keloids have increased odds risk of arthrofibrosis following primary TKA. These patients are subsequently at a higher odds risk of undergoing the procedures necessary to treat arthrofibrosis, such as MUA and LOA. Future studies investigating confounding factors such as race, prior surgery, range of motion, and postoperative recovery are needed to confirm the association of keloid diagnosis and arthrofibrosis following primary TKA demonstrated in this study. LEVEL OF EVIDENCE: Level III retrospective comparative study.