Stiffness after total knee arthroplasty (TKA) remains a significant postoperative complication with prevalence ranging from 1.3% to 12%. This condition can impair patient satisfaction and functional outcomes. Arthroscopic arthrolysis (AA) is a minimally invasive procedure used to address stiffness, but current literature primarily focuses on short-term results in small cohorts. Therefore. there is a need for a large study with a long-term follow-up and a large sample size study to evaluate this procedure. The current investigation aimed to determine: 1) if patients who benefited from an AA for stiffness in both flexion and extension after TKA present a significant improvement of 20° in their range of motion (ROM) at mid-term follow-up, 2) the functional scores and the complications including reoperations and revisions.

Arthroscopic arthrolysis allows a significant improvement of 20° in their range of motion (ROM) at mid-term follow-up.

This retrospective cohort study included 85 patients (47 women and 38 men, mean age at 61.5 ± 10.6 years) from nine centers of the SOFCOT symposium database, who underwent AA for stiffness following primary TKA between January 2015 and December 2019. Patients with manipulation under anesthesia (MUA), open arthrolysis or revision surgery were excluded. ROM was assessed before TKA, at stiffness diagnosis and at the final follow-up. Functional outcomes were evaluated using the Oxford Knee Score, KOOS subscales, and the Forgotten Joint Score-12 (FJS-12). Satisfaction rate, perioperative and postoperative complications, reoperations and revisions were recorded.

The mean time from TKA to AA was 9.9 ± 13 months. Patients were followed for a mean duration of 6 ± 3.1 years. ROM significantly improved from 65.4° ± 24° at diagnosis to 86.5° ± 34° at last follow-up of 6 years (Δ = 21.1°. p < 0.01). However pre-TKA ROM (106.6° ± 23°) was not fully restored (Δ = −20.1°. p < 0.01). Flexion significantly improved from 72.2° ± 20° at diagnosis to 89.5° ± 31° at last follow-up. No significant improvement in extension was observed with an extension at diagnosis at 6.8° ± 7° and at 3° ± 9.1° at last follow-up. The functional scores at follow-up were 28.9 ± 9.8 [5; 46] for the Oxford score; 61.0 ± 18.6 [25; 100] for KOOS symptoms; 63.2 ± 17.9 [33; 100] for KOOS pain; 63.1 ± 18.9 [31; 100] for KOOS daily activities; 31.4 ± 27.1 [0; 92] for the KOOS sport/recreation; 55.3 ± 26.9 [13; 100] for KOOS quality of life; 46.1 ± 11.2 [12; 60] for the FJS-12 score. Only 58.9% (43/73) of patients without revision or salvage procedure were satisfied. Eighteen patients (21.2%) underwent reoperation: 6 (7.1%) without implant revision, 10 (11.8%) implant revisions (3 stiffness recurrence, 3 late infection, 2 instability, 1 allergy, 1 aseptic loosening), and 2 salvage procedures (1 arthrodesis, 1 transfemoral amputation). No correlation was found between the delay to AA and ROM gain (R = 0.09, p = 0.47).

AA provides a significant mid-term improvement in joint flexion for patients suffering from post-TKA stiffness with no major complication related to the surgery. The patient satisfaction remains moderate and a significant proportion required further surgery primarily due to recurrent stiffness or other complications. These results highlight the need for a complete preoperative assessment, with systematic infectious workup and careful patient selection.

IV; multicenter retrospective cohort study.