Early reconstruction should be considered in younger patients with symptomatic mucoid degeneration of the anterior cruciate ligament

Do the Clinical and Radiological Features of Knees with Mucoid Degeneration of the Anterior Cruciate Ligament Differ According to Knee Osteoarthritis Status?

Background

The etiology and pathology of mucoid degeneration of the anterior cruciate ligament (MD-ACL) remain poorly understood. MD-ACL may be associated with knee osteoarthritis (OA) or a mechanism other than OA. This study evaluated the radiological differences between knees with MD-ACL and those with a normal ACL and compared the clinical and radiological features of knees with MD-ACL according to the knee OA status.

Methods

This retrospective study compared the radiological features of the intercondylar notch width index (NWI) and posterior tibial slope (PTS) of 67 MD-ACL patients (MD group) and 67 age-, sex-, and OA grade-matched patients with a normal ACL (control group). During the subgroup analysis, MD-ACL patients were divided into the non-OA subgroup (n = 41) and OA subgroup (n = 26). The pain location and characteristics of the knee, PTS, and NWI were compared between these subgroups.

Results

Compared to the control group, the MD group had a lower NWI (0.26 ± 0.03 vs. 0.28 ± 0.01, p < 0.001) and a larger PTS (11.3° ± 3.0° vs. 9.2° ± 2.5°, p < 0.001). During the subgroup analysis, the most common pain locations were the posterior and medial aspects of the knee in the non-OA subgroup (43.9%) and OA subgroup (53.8%), respectively. Pain on terminal flexion was the most common pain characteristic in both subgroups (non-OA subgroup, 73.1%; OA subgroup, 53.8%). The PTS was not different between subgroups (11.7° ± 3.2° in the non-OA subgroup vs. 10.6° ± 2.7° in the OA subgroup; p = 0.159). However, the non-OA subgroup had a lower NWI than the OA subgroup (0.25 ± 0.03 vs. 0.28 ± 0.02, p = 0.001).

Conclusions

Patients with MD-ACL had a lower NWI and a larger PTS than patients with a normal ACL. Furthermore, the clinical and radiological features of MD-ACL differed according to the knee OA status. A narrow intercondylar notch may be more closely associated with the development of MD-ACL without OA.

Reconstruction Considerations Following Complete Excision of Mucoid-Degenerated Anterior Cruciate Ligament: A Retrospective Study

INTRODUCTION

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is an unusual cause of knee pain and restricted movement, predominantly affecting the middle-aged population. Arthroscopic partial or total debridement of the mucoid ACL is the surgical treatment of choice. However, little is discussed in the literature regarding subsequent knee instability and functional outcomes following complete ACL excision.

METHODS

A retrospective study was conducted on patients who underwent arthroscopic total ACL excision for mucoid ACL. Pre- and post-operatively, the Tegner-Lysholm score, the International Knee Documentation Committee (IKDC) Subjective Knee Form, and subjective functional instability were used to grade the clinical outcomes.

RESULTS

Ten out of the 13 patients who underwent complete ACL excision were available for evaluation. All patients presented with knee pain on deep flexion or extension with a painfully limited range of motion. Post-operatively, all patients were relieved of their original pain and dysfunction. The mean post-operative IKDC and Tegner-Lysholm scores were 74.96 and 83.6, respectively. All patients had a Lachman test positive, while only two had a grade 1 pivot shift test positive. Two patients had occasional functional instability only after strenuous exercises. None of the patients underwent subsequent ACL reconstruction.

CONCLUSION

All patients reported improved functional outcomes. Only two out of 10 reported occasional instability during strenuous activity. Therefore, complete debridement of mucoid ACL in sedentary patients is safe and efficacious. However, active young patients may experience instability and require ACL reconstruction if it hinders their daily activities.

Clinical outcomes of arthroscopic partial resection of mucoid degeneration of anterior cruciate ligament

PURPOSE

Mucoid degeneration of the anterior cruciate ligament is rare condition; mucoid degeneration affects the range of motion of the knee with pain on terminal extension and terminal flexion. Arthroscopic treatment of the mucoid anterior cruciate ligament (ACL) is the treatment of choice. The purpose of this study was to provide demographic and clinical characteristic of mucoid degeneration of ACL and assess the outcomes of partial arthroscopic ACL resection.

METHODS

Patients who underwent partial ACL resection for mucoid degeneration between February 2007 and February 2019 were considered for study eligibility. Patients were evaluated for International Knee Documentation Committee (IKDC), The Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI), The Knee injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale.

RESULTS

Sixty patients underwent partial ACL resection for mucoid degeneration of the ACL. Nine patients were lost to follow-up, 43 were males, the average age was 52.12±12.09 and a mean follow-up of 83.55±44.79 months. At final follow-up six patients underwent ACL reconstruction for ACL rupture (11.7%) at an average of 15.66±12 months. Patient satisfaction was at 71%.

CONCLUSION

Arthroscopic partial resection of the ACL led to good clinical outcome for treating mucoid degeneration of the ACL.

Partial debridement is the most commonly reported treatment option for mucoid degeneration of the anterior cruciate ligament: a systematic review

PURPOSE

To determine clinical outcomes and risks of various management strategies for mucoid degeneration of the anterior cruciate ligament (MD-ACL).

METHODS

Three databases MEDLINE, PubMed and EMBASE were searched from inception to January 29th, 2023 for literature outlining clinical outcomes for various management strategies of MD-ACL. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on satisfaction scores, visual analogue scale (VAS) scores, Lysholm scores, International Knee Documentation Committee (IKDC) scores, Knee Osteoarthritis and Outcome Scores (KOOS), range of motion and Lachman test were recorded.

RESULTS

A total of 14 studies comprising 776 patients (782 knees) were included in this review. Partial debridement was reported in ten (71.4%) studies comprising 446 patients, showing significant improvements in VAS, Lysholm, IKDC scores and range of motion. Complete debridement was reported by two (14.2%) studies comprising 250 patients, and resulted in increases in Lysholm scores, KOOS, and range of motion. Reduction plasty was reported in two (14.2%) studies comprising 26 patients and showed improvements in VAS and Lysholm scores, and range of motion. Other methods of treatment included conservative management and ultrasound decompression. Complete debridement resulted in 10/23 (43%) patients with a positive Lachman test. This was followed by reduction plasty and partial debridement, with 5/26 (19.2%) and 45/340 (13.2%) patients respectively having positive Lachman or elevated knee arthrometer scores. Pivot shifting was only reported in studies on partial debridement and reduction plasty, with 14/93 (15.1%) and 1/21 (4.8%) patients have positive results, respectively.

CONCLUSION

The most commonly reported management strategy for MD-ACL is partial debridement with complete debridement, reduction plasty and conservative management as alternative options. Current operative management strategies place individuals at risk for ACL insufficiency. Information from this review can aid surgeons and clinicians in understanding what treatment options are best for this patient population, by understanding the reported clinical benefits and risks of each strategy.

LEVEL OF EVIDENCE

IV.