Unusual solid ganglia of the anterior cruciate ligament mimicking lateral meniscal tears

Anterior cruciate ligament mucoid degeneration: a review of the literature and management guidelines

PURPOSE

Anterior cruciate ligament (ACL) mucoid degeneration is a rare encounter in clinical practice, different, but often confused with ACL mucoid cysts. Its pathophysiology remains unclear. However, recent publications have suggested that it might be underdiagnosed or misdiagnosed, and that the adverse effects of treatment by ACL resection might be underestimated. The object of this work was to summarize this scattered knowledge to improve patient management.

METHODS

The authors carried out an exhaustive and comprehensive review of up-to-date literature. An extensive search of the MEDLINE database was carried out using MESH terms (ganglion cyst, anterior cruciate ligament) and generic search terms (mucoid degeneration, hypertrophy).

RESULTS

Anterior cruciate ligament mucoid degeneration is determined by interstitial glycosaminoglycan deposits amidst the collagen bundles causing ACL hypertrophy, knee pain, and limited range of motion. It is thought to arise from a primary synovial lesion and is associated with arthritic change or subsequent to acute or repeated trauma. Diagnosis is made on MRI scans and confirmed on histopathological samples. Current treatment involving ACL arthroscopic resection is efficient on pain and range of motion but is not a benign procedure and causes knee laxity.

CONCLUSIONS

Anterior cruciate ligament mucoid degeneration needs to be more broadly known and properly diagnosed so that progress can be made in its management. Further research will be necessary to confirm the current trends in the literature, which suggest being less aggressive with ACL arthroscopic resection when dealing with mucoid degeneration and making more use of conservative measures such as notchplasty.

LEVEL OF EVIDENCE

Systematic review, Level IV.

Large extrasynovial intracapsular ganglia of the knee: a report of 3 cases

PURPOSE

Intra-articular ganglia of the knee are rare and usually incidental findings of little clinical significance. Nevertheless some are large, symptomatic, and require treatment. We report on 3 patients with an intra-articular knee ganglion and an extrasynovial extension that was contained within the joint capsule. This seems to be a rare condition; a review of the English-language literature revealed no reports of similar cases.

TYPE OF STUDY

Case series.

METHODS

Three patients, 1 man and 2 women aged 27 to 40 years, presented with an almost identical history of anterior knee pain that had been treated conservatively for a long time as chondromalacia patellae. The symptoms, which were ill-defined, appeared to be deteriorating until a localized swelling appeared on the lateral side of the patella tendon in each case. On examination, a lateral meniscal cyst associated with an underlying meniscal tear was suspected. However, magnetic resonance imaging revealed a ganglion arising from the substance of the anterior cruciate ligament (case 1) and from the area of the tibial insertion of the anterior cruciate ligament (cases 2 and 3). All 3 ganglia extended anteriorly and then laterally over and in front of the lateral meniscus. The ganglia were approached through an anterior midline incision and lateral parapatellar arthrotomy, which allowed direct and easy access for complete excision. Histologic examination confirmed the diagnosis of a ganglion in all 3 cases.

RESULTS

The postoperative course was uneventful in all patients with no signs of recurrence at 1 year (case 1), 2 years (case 2), and 3 years (case 3).

CONCLUSIONS

Although the described condition seems very rare, we believe that it should be included in the differential diagnosis of cystic lesions about the knee joint.

LEVEL OF EVIDENCE

Level IV, case series, no, or historical control group.