Purpose Impaired patient outcome can be directly related to a loss of motion of the knee following surgical procedures. If conservative therapy fails, arthroscopic arthrolysis is an effective procedure to improve range of motion (ROM). The purpose of this study was to evaluate the outcome of patients undergoing very early (< 3 months), early (3 to 6 months), and late (> 6 months) arthroscopic arthrolysis of the knee. Methods With a follow-up on average at 35.1 ± 15.2 (mean ± SD, 24 to 87) months, 123 patients with post-operative motion loss (> 10° extension deficit/ < 90° of flexion) were included between 2013 and 2018 in the retrospective study, while eight patients were lost to follow-up. A total of 115 patients were examined with a minimum follow-up of two years. Twenty percent (n = 23) of patients of this study population had a post-operative motion loss after distal femoral fracture, 10.4% (n = 12) after tibial head fracture, 57.4% (n = 66) after anterior/posterior cruciate ligament (ACL/PCL) reconstruction, 8.7% (n = 10) after infection of the knee, and 3.4% (n = 4) after patella fracture. Thirty-seven patients received very early (< 3 months, mean 1.8 months) arthroscopic arthrolysis, and 37 had early (3 to 6 months, mean 4.3 months) and 41 late (> 6 months, mean 9.8 months) arthroscopic arthrolysis after primary surgery. Results The average ROM increased from 73.9° before to 131.4° after arthroscopic arthrolysis (p < 0.001). In the group of very early (< 3 months) arthroscopic arthrolysis 76% (n = 28) of the patients had a normal ROM (extension/flexion 0/140°), in the group of early (3–6 months) arthrolysis 68% (n = 25) of the patients and in the group of late arthrolysis 41.5% (n = 17) of the patients showed a normal ROM after surgery (p = 0.005). The total ROM after arthrolysis was also significantly increased in the group of very early and early arthrolysis (136.5° and 135.3° vs. 123.7°, p < 0.001). A post-operative flexion deficit occurred significantly less in the group of very early and early arthroscopic arthrolysis compared to the late arthroscopic arthrolysis (3.9° and 4.2° vs. 16.6°, p < 0.001). Patients treated with very early (< 3 months) and early (3 to 6 months) showed a significantly increased post-operative Tegner score of 4.8 ± 1 and 4.7 ± 1.1 compared to 3.8 ± 1.1 in the group of late arthroscopic arthrolysis (> 6 months, p < 0.001). Conclusions An arthroscopic arthrolysis is highly effective and leads to good to excellent mid-term results. An early arthroscopic arthrolysis within 6 months after primary surgery leads to significantly improved ROM and functional scores compared to the late arthrolysis (> 6 months).

Aims and Objectives: Distal femoral or tibial fractures as well as anterior cruciate ligament (ACL) tears can be associated with postoperative arthrofibrosis of the knee. So far, there are only a few studies that analyse this entity. The aim of the study is to evaluate potential risk factors that influence the outcome of patients with arthrofibrosis. We hypothesize that early arthroscopic arthrolysis is associated with a better postoperative outcome. Materials and Methods: 100 patients (at the time of the abstract submission n=59) with arthroscopic arthrolysis of postoperative arthrofibrosis of the knee were included in the retrospective study. They were clinically examined with a minimum follow-up of 2 years (mean 25±6 months). Arthrofibrosis was shown in 51% of the cases after ACL lesions, in 14% after femoral and tibial fractures, in 12% after infection and in 10% after patella fractures. The study population was divided into early (less than 3 months; n=19, mean 1.5 months) and late (more than 3 months; n=40, mean 8.7 months) arthroscopic arthrolysis after primary surgery. Results: In 51% of the cases (n=30) a normal range of motion could be postoperatively achieved (extension/flexion 0/140°). Patients with early arthroscopic arthrolysis showed significant more often a normal postoperative range of motion in comparison to patients with late revision (84% vs. 35%; p<0.001). Furthermore, patients with early arthrolysis had a significant lower postoperative flexion deficit than the late arthrolysis group (4° vs. 27°, p<0.001). The postoperative extension deficit was also significantly lower in the early arthrolysis group (0.4° vs. 3°; p=0,021). Postoperative functional scores were significantly higher after arthroscopic arthrolysis in comparison to before arthrolysis (Lysholm 85,1±11 vs. 41,3±9, p=0,049; Tegner 6,1±1 vs. 3,2±2, p=0,035; Cincinnati Rating Scale 83,1±13 vs. 52,1±16, p=0,046). Conclusion: Arthrofibrosis of the knee can be successfully treated with arthroscopic arthrolysis. Good postoperative results can be gained in treating flexion and extension deficits. Early arthroscopic arthrolysis shows significant better results in postoperative range of motion in comparison to late arthroscopic arthrolysis.