Outcome of Arthroscopic Treatment of Mucoid Degeneration of the Anterior Cruciate Ligament

Abstract

Background: Mucoid degeneration of the anterior cruciate ligament is a rare pathological entity. Several authors have identified this condition, described their experiences, and suggested their own guidelines for management. The aim of this study was to detail the clinical, radiological, arthroscopic, and pathological findings of mucoid degeneration of the anterior cruciate ligament and report the clinical outcomes following arthroscopic treatment.

Methods: A historical cohort of patients who underwent arthroscopic total or partial excision of the anterior cruciate ligament due to mucoid degeneration between 2011 and 2014 were reviewed. The minimum follow-up was 3 years. Demographic, radiological, and histological findings, type of surgery, and clinical pre- and postoperative data were analyzed. The visual analogue scale score, the International Knee Documentation Committee score, and the Tegner Lysholm Knee Score were collected preoperatively, postoperatively, and during the follow-up period.

Results: Seventeen females (67%) and eight males (33%) were included in the final analysis. The mean age at the time of surgery was 57 years (range, 31 to 78 years). Partial resection of the anterior cruciate ligament was done in seven cases and a complete resection in 18 cases. No reconstruction was performed at the same time. A positive Lachman test and a negative pivot shift were noted after surgery in all cases. Anterior cruciate ligament reconstruction was required in only one young patient due to disabling instability. At last follow-up, the mean visual analogue scale score, International Knee Documentation Committee score, and Tegner Lysholm Knee score improved (p < 0.01).

Conclusions: Our study provides further evidence that arthroscopic total or partial excision of anterior cruciate ligament is a safe and effective treatment for mucoid degeneration of the anterior cruciate ligament, improving patient satisfaction and function without causing clinical instability in daily activities. However, young patients should be forewarned about the risk of instability, and an anterior cruciate ligament reconstruction could be necessary.

Keywords: Anterior cruciate ligament; Arthroscopy; Knee; Mucoid degeneration.

Fig. 1. Preoperative magnetic resonance imaging (MRI) scan. Sagittal T2-weighted MRI view showing intact anterior cruciate ligament fibers with mucoid degeneration.

Fig. 2. Arthroscopic findings. (A) Bulging of the hypertrophied anterior cruciate ligament. (B) Partial resection (anteromedial bundle) of the anterior cruciate ligament.