ARTHROSCOPIC TREATMENT OF MUCOID DEGENERATION OF THE ANTERIOR CRUCIATE LIGAMENT: MEDIUM TERM FOLLOW-UP RESULTS ABOUT 29 CASES

Abstract

Introduction: Clinical presentation of mucoid degeneration of the anterior cruciate ligament (MDACL) associated knee flexion limitation and posterior knee pain. Treatment needs an anterior cruciate ligament resection, with some questions about harmlessness of this procedure. Our hypothesis was that arthroscopic MDACL treatment is an effective procedure for pain and mobility but creates some anterior knee laxity.

Materials and Methods: This is a retrospective cohort study including 29 cases of MDACL (19 men, 8 women). Mean age was 49 years (range 28 to 68). Mean follow-up was 6 years. Diagnosis was done associated clinical and MRI criteria and was confirmed using Mc Intyre’s arthroscopic criteria. A histological analysis was done in 18 cases. Postoperative functional evaluation was done using IKDC and KOOS score. Knee laxity was appreciated using clinical evaluation and radiological evaluation by TELOS measurement. Statistical analysis was done using Student t-test (level of significance: p< 0.005).

Results: Preoperatively, posterior knee pain was present in 23 knees, and knee flexion limitation in 14 cases. In 10 cases, MDACL was initially misdiagnosed with an inappropriate primary operative treatment. None of theses patients have an anterior knee laxity. Partial anterior cruciate ligament resection was done in 12 cases and complete resection in 17 cases. Meniscectomy was associated in 11 cases. In cases with histological study, diagnosis was always confirmed. After resection knee was painless in 27 cases, and knee flexion increase was 21.52°. A positive Lachman’s test was noted after surgery in all cases, (with a positive Jerk test in 8 cases). Postoperative radiological laxity was greater on the operated side (operated knee vs normal knee: 12.64 /4.33 mm, p< 0.001) Two young patients have need secondary an ACL reconstruction. Two old patients have needed secondary knee prosthesis after 2 and 3 years. Mean postoperative IKDC score was 71.19 (range 42.53 to 91.95) and mean postoperative KOOS score was 78.16 (range 26.40 to 99). Statistical analysis have showed better results for patient older than 50 years, after partial resection and for patient without meniscal associated lesions.

Discussion: Mucoid degeneration of the anterior cruciate ligament should not be confused with anterior cruciate ligament ganglia. Accurate diagnosis could be done using clinical, MRI and arthroscopic diagnosis criteria’s. Arthroscopic treatment of MDACL is an efficient procedure for knee pain and to restore a better knee flexion. However, this procedure created a signifiant anterior knee laxity and could lead in some cases to knee instability especially in young patients.