Imaging finding and arthroscopic treatment of isolated contracture of the rectus femoris muscle: a case report

BACKGROUND: Isolated rectus femoris (RF) contracture is encountered very rarely in orthopaedic practices. There are few reports on its imaging manifestations and no cases reported to be treated with arthroscopy. CASE PRESENTATION: A 11-year-old girl with a more than 7 years history of restricted left knee flexion was presented. The clinical assessment and magnetic resonance imaging (MRI) findings were detailed here. A strip-like induration was palpated in the left thigh, which tends to be more obvious with knee flexion. MRI demonstrated a hypointensity band connected the anterior inferior iliac spine with the patella, and marked atrophy of the left RF muscle. Fibrosis contracture band was confirmed with arthroscope, then divided by radiofrequency ablation (RFA) under arthroscopic observation. Followed by debridement of the fibrillar connective tissue and hemostasis around the broken ends. The movement of left knee joint significantly improved after the operation, and the patient recovered nearly full range of motion of this joint after 6 months. CONCLUSION: The specific MRI findings could assist in confirming clinical early diagnosis of isolated RF contracture. Arthroscopic RFA treatment is an effective technique to treat this disorder with minimally incision. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12891-019-2696-8) contains supplementary material, which is available to authorized users.