Prognostic factors for tibiofemoral and patellofemoral osteoarthritis 32-37 years after anterior cruciate ligament injury managed with early surgical repair or rehabilitation alone

Objective: Explore prognostic factors for tibiofemoral (TFJ) and patellofemoral (PFJ) radiographic osteoarthritis (ROA) and symptoms plus ROA (SOA), 32-37 years following anterior cruciate ligament (ACL) injury. Design: Exploratory analysis, longitudinal cohort. Methods: In 1980-1985, 251 patients aged 15-40 years with acute ACL rupture were allocated to early augmented or non-augmented repair (5 +/- 4 days post-injury) plus rehabilitation, or rehabilitation alone. 127 of 190 participants who completed follow-up questionnaires were eligible. We classified ROA as TFJ/ PFJ K&L Grade >2, and SOA as ROA plus pain and/or symptoms. Multivariable age-adjusted logistic regression investigated potential prognostic factors (assessed at 4 +/- 1 year follow-up: ACL treatment, isokinetic quadriceps/hamstrings strength, single-leg-hop for distance, knee flexion/extension deficit, knee laxity, Tegner Activity Scale, Lysholm Scale; sex, baseline meniscus status). Results: 127 patients were aged 58 +/- 6 years; BMI 27 +/- 4 kg/m2; 28% female; 59% had TFJ-ROA, 48% had TFJ-SOA (including n = 9 knee-arthroplasties), 36% had PFJ-ROA; 27% had PFJ-SOA. Baseline meniscus surgery was a prognostic factor for TFJ-ROA (multivariable age-adjusted odds ratio (95% CI): 3.0 (1.2, 7.8)). A single-leg-hop limb symmetry index (LSI) < 90% was a prognostic factor for PFJ-ROA (5.1 (1.4, 18.7)) and PFJ-SOA (4.9 (1.2, 19.7)). Hamstrings strength LSI <90% was a prognostic factor for PFJ-SOA (5.0 (1.3, 19.3)). ACL treatment with rehabilitation-alone was associated with an 80% reduction in the odds of PFJSOA (0.2 (0.1-0.7)), compared with early ACL-repair. Conclusions: These findings are hypothesis generating, research is needed to determine whether ACLinjured individuals with these characteristics benefit from interventions to prevent or delay the onset of osteoarthritis. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of Osteoarthritis Research Society International. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Funding Agencies|Centre for Sport, Exercise and Osteoarthritis Research Versus Arthritis; United Kingdom [21595]; National Health and Medical Research Council (NHMRC) Emerging Leadership FellowshipNational Health and Medical Research Council of Australia; Linkoping University, Sweden