Clinical and radiological comparison between partial and complete resection of the anterior cruciate ligament in patients with mucoid degeneration of the anterior cruciate ligament: a controlled clinical trial

Severe mucoid degeneration of the anterior cruciate ligament (ACL) treated with conservative arthroscopic debridement and platelet-rich plasma (PRP) injection

Mucoid degeneration of the anterior cruciate ligament (ACL) can be treated with arthroscopic debridement, however, instability can ensue. Here, we present a fit and active woman in her 60s with severe mucoid degeneration of the ACL who underwent conservative arthroscopic debridement and treatment with intraligamentous administration of platelet-rich plasma (PRP). After 1 month, the patient demonstrated significant improvements in range of motion and pain symptoms, with nil resultant laxity. The patient was able to return to all recreational sporting activities and professional duties. Quantitative MRI conducted 6 months postoperatively revealed improved fibre orientation and formation of new parallel fibres. Compared with the preoperative scan, the mean grey value demonstrated darker pixel intensity with a smaller standard deviation (SD), potentially indicating a more uniform and less variable formation of ligamentous tissue. Therefore, PRP did not cause harm and was associated with benefit in combination with arthroscopic debridement.

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.

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.

ACL Mucoid Degeneration-Anterior and Posterior Arthroscopic Decompression for Combined Knee Flexion-Extension Deficit

Mucoid degeneration of the ACL (MDACL, ACL ganglion cysts) is a disease involving ACL thickening due to accumulation of mucoid substance and fiber degeneration with possible formation of "ganglions". Clinically, it leads to anteroposterior impingement and painful limitation of knee range of motion due to impingement of the anterior portion of the thickened ACL with the intercondylar notch during knee extension and the thickened posterior part of the ligament with posterior structures of the knee in flexion. Different treatment methods have been described, including total or partial resection of the ACL degenerative fibers. However, these techniques do not allow for ACL preservation and are associated with a risk of postoperative instability. Also, most procedures treat anterior impingement only. Therefore, the aim of this technical note is to present an arthroscopic technique allowing for minimally invasive anteroposterior ACL decompression. The technique is focused on evacuation of the interfibrous mucoid substance, ganglions, and bony decompression, as well as maintenance of ligament integrity. Its greatest advantage is that it is safe and ACL-preserving yet allows for comprehensive treatment of all intra- and extra-ligamentous possible reasons of MDACL origin and promoting good healing conditions.

Posterior tibial slope, notch width index and tibial tubercle to trochlear groove distance contribute to development of mucoid degeneration of the anterior cruciate ligament: a systematic review

PURPOSE

To determine what knee morphological factors are associated with the development of mucoid degeneration of the anterior cruciate ligament (ACL).

METHODS

Three databases MEDLINE, PubMed and EMBASE were searched from inception to January 29th, 2023 for literature outlining knee morphological factors that potentially lead to the development of mucoid degeneration of the ACL. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on receiver operating characteristic (ROC) curve parameters such as area under the curve (AUC), sensitivity and specificity, odds ratios, as well as p values for comparisons of values between mucoid degeneration of the ACL and control patients were recorded. The Methodological Index for Non-Randomized Studies (MINORS) score was used for all studies to perform a quality assessment of included studies.

RESULTS

A total of 7 studies comprising 1326 patients (1330 knees) were included in this review. Four studies reported a significant association between increasing posterior tibial slope angles and mucoid degeneration of the ACL presence, with one study specifying that posterolateral tibial slope had a greater association than posteromedial tibial slope. Two studies reported a significant association between lower notch width index values and mucoid degeneration of the ACL presence. One study found that the presence of trochlear dysplasia was correlated with mucoid degeneration of the ACL and two studies found that increased tibial tuberosity-trochlear groove distance (TT-TG) was associated with mucoid degeneration of the ACL.

CONCLUSION

Increased posterior tibial slope, decreased notch width index, and elevated TT-TG and trochlear dysplasia were associated with the presence of mucoid degeneration of the ACL. Information from this review can aid surgeons in understanding what morphological features predispose their patients to the development of mucoid degeneration of the ACL. Identifying what features predispose patients to mucoid degeneration of the ACL can help determine if regular screening or preventative strategies are necessary.

LEVEL OF EVIDENCE

Level III.