The fabella syndrome - a rare cause of posterolateral knee pain: a review of the literature and two case reports

Abstract

BackgroundThe purpose of this article was to evaluate the risks and benefits of non-operative treatment versus surgical excision of a fabella causing posterolateral knee pain. We performed a systematic review of literature and also present two case reports.Twelve publications were found in a PubMed literature review searching the word “fabella syndrome”. Non-operative treatment and surgical excision of the fabella has been described.Case presentationTwo patients presented to our outpatient clinic with persisting posterolateral knee pain. In both cases the presence of a fabella was identified, located in close proximity to the posterolateral femoral condyle. All other common causes of intra- and extra articular pathologies possibly causing the posterolateral knee pain were excluded.Following failure to respond to physiotherapy both patients underwent arthroscopy which excluded other possible causes for posterolateral knee pain. The decision was made to undertake surgical excision of the fabella in both cases without complication.Both patients were examined 6 month and one year after surgery with the Tegner activity score, the Visual Analogue Scale (VAS), and International Knee Documentation Committee Score (IKDC).ConclusionConsistent posterolateral pain during exercise might indicate the presence of a fabella syndrome. Resecting the fabella can be indicated and is a minor surgical procedure with minimal risk. Despite good results in the literature posterolateral knee pain can persist and prevent return to a high level of sports. Level of evidence: IV, case reports and analysis of literature.

Transosseous Repair of Root Tears of the Lateral Meniscus: Operative Technique and Short-Term Clinical Follow-Up of 28 Patients

“…Clinically a PLMRT shows similar symptoms as other meniscal injuries such as tenderness in the joint line and 2 Advances in Orthopedic Surgery positive meniscus tests and therefore cannot be distinguished clinically from other meniscal pathologies [2,[12][13][14].…”

Arthroscopy-Assisted Fabella Excision: Surgical Technique

“…1 The presence of the fabella in humans is a variant and is reported to range from 20% to 87%. 2 When the fabella is present, an additional ligament called the fabellofibular ligament (ligament of Vallois), which runs from the fabella to the fibular head, can be found. 2 The presence of the fabella is usually asymptomatic; however, it can be a source of posterolateral knee pain.…”

“…2 When the fabella is present, an additional ligament called the fabellofibular ligament (ligament of Vallois), which runs from the fabella to the fibular head, can be found. 2 The presence of the fabella is usually asymptomatic; however, it can be a source of posterolateral knee pain. 2,3 The pain is usually periodic and is accentuated with the knee in extension, because of the compression of the fabella against the lateral femoral condyle in this position.…”

“…2 The presence of the fabella is usually asymptomatic; however, it can be a source of posterolateral knee pain. 2,3 The pain is usually periodic and is accentuated with the knee in extension, because of the compression of the fabella against the lateral femoral condyle in this position. 4 Irritation of the common peroneal nerve resulting in neurologic symptoms, such as numbness or pain, may be present in some patients.…”

“…[2][3][4] Nonoperative treatment centers on steroid injection into the area of maximum palpable discomfort and temporary restriction of activities. In the report detailing the largest number of patients (n ¼ 16) treated for pain resulting from the presence of a fabella, Weiner and Macnab 4 described treatment outcomes for 11 patients treated operatively and 5 patients treated nonoperatively.…”