Knee Deep In Inflammation: Effusion-synovitis And Hoffa Synovitis As Early Oa Signals Post-aclr

Persistent knee inflammation often follows ACL injury and reconstruction. Effusion-synovitis and Hoffa synovitis are inflammation markers potentially linked to osteoarthritis (OA), but their association with early OA symptoms post-ACLR is unclear. PURPOSE: To examine the relationship between ultrasound-assessed effusion-synovitis and Hoffa synovitis in the ACLR limb and the presence of early OA symptoms in patients post-ACLR. METHODS: 32 patients (female = 14; height = 168.6 ± 8.9 cm; mass = 75.5 ± 21.7 kg; age = 19.0 ± 5.3 yrs; time post-ACLR = 4.9 ± 1.1 mo) were included. ACLR Knee ultrasound scans were used to assess effusion-synovitis and Hoffa synovitis. Effusion-synovitis was graded using a semi-quantitative OA ultrasound scale (0 = absent, 1 = mild, 2 = moderate, 3 = severe). Hoffa synovitis was measured by echo-intensity (EI) of the infrapatellar fat pad, segmented one centimeter deep to the patellar tendon. Limb symmetry index (LSI) values were calculated for differences between the ACLR and contralateral limbs. Effusion-synovitis was reclassified as "yes" for grades ≥2 and "no" for grades 0-1, while Hoffa synovitis used an established cutoff, with "yes" for EI LSI values ≥22% and "no" for values <22%. Early OA symptoms were identified using the Luyten PASS criteria, with patients scoring below the threshold on two or more Knee Osteoarthritis Outcome Score (KOOS) subscales classified as symptomatic. A binary logistic regression was used to determine if early OA symptoms were associated with effusion-synovitis and Hoffa synovitis. RESULTS: Among the 32 patients, 15 (46%) had effusion-synovitis, 8 (25%) exceeded the Hoffa synovitis cutoff, and 17 (53%) met criteria for early OA symptoms. Effusion-synovitis in the ACLR limb was not significantly associated with early OA symptoms (odds ratio [OR] = 1.68, CI: 0.42-7.15, p = 0.47). Hoffa synovitis was not significantly associated with early OA symptoms (OR = 0.43, CI: 0.07-2.16, p = 0.31). CONCLUSION: Effusion-synovitis and Hoffa’s synovitis were prevalent findings five months post-ACLR. However, neither marker demonstrated a significant association with early OA symptoms, despite most patients meeting the criteria for these symptoms. These findings suggest that alternative factors may play a greater role in the presence of early OA symptoms early post-ACLR. Supported by: This work was supported by a National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) grant (K01 AR081389). ChatGPT was used to enhance readability and language of this abstract.