Description
Objectives: The presence of an ACL or PCL ganglion cysts is a rare condition, but one that should be considered in the differential diagnosis when encountering a patient with nonspecific pain in the posterior area of the knee. Chronic pain in the posterior area of the knee in middle aged patients, along with limitations in flexion-extension or locking, are common findings in most patients with symptomatic ACL ganglion cysts, although there is no specific clinical pattern.
The aim of this study was to analyze the sample of patients diagnosed with an ACL ganglion in the past year.
Methods: A retrospective study was conducted on 11 patients, 9 of whom were male and 2 were female, with ages ranging from 19 to 56 years and a median age of 30.5 years.
All patients presented with knee pain of 1 month to 2 years (median of 5 months). 75% on the right side and 25% on the left side. Among them, 75% experienced pain in the posterior aspect of the knee, 12.5% in the medial aspect, and 12.5% reported generalized pain. None of them had associated symptoms such as inflammation, locking, instability, or functional limitations of the knee. Except for one patient, none of the others reported a traumatic history.
All patients exhibited the presence of a ganglion associated with the central pivot on MRI. In 50% of cases, it was an intrasubstance ganglion of the ACL, in 37.5%, it was located between the two cruciate ligaments, and in the remaining 12.5%, it was at the proximal insertion of the ACL. In 25% of the MRIs, the ganglion was the only finding, but in the others, in addition to the ganglion, other associated lesions were observed, such as mucoid degeneration and bone edema of the lateral femoral condyle, mixed degeneration of the anterior horn of the external meniscus and ACL, femoropatellar chondral lesion, stable lateral meniscus lesion, parameniscal medial cystic lesions, and medial meniscus lesions.
Results: In 62.5% of our cases, therapeutic abstention was chosen for the ganglion cysts, considering that the symptoms could be due to other associated injuries.
Three of our patients underwent arthroscopic intervention for ganglion removal. Symptoms disappeared only in 2 of these patients.
Conclusions: Ganglion of the ACL and PCL is a rare condition with an unknown etiology that should be considered in the differential diagnosis of nonspecific knee pain. Posterior knee pain with negative meniscal tests and difficulty in flexion is perhaps the most common presentation.
Despite the fact that, many ACL ganglion cysts are asymptomatic, when they begin to show symptoms, the delay in their diagnosis can cause greater involvement of the ACL fibers and can lead to greater difficulty in resection without ligamentous injury. MRI is a good imaging tool for diagnosis confirmation.
Partial resection of the ACL may not be sufficient to reduce pain, while there is a risk of postoperative instability and a subjective knee “giving way”.
