Anatomy
The anterior cruciate ligament is an important structure of the knee joint. Anatomically, it crosses the posterior cruciate ligament to form an “X” shape, hence the name cruciate ligament. This ligament is composed of two fibers, mainly the anteromedial and The posterolateral fibers, respectively. The ligaments are primarily responsible for limiting forward motion of the knee joint. Among other things, it also controls the internal rotation. Therefore, an ACL tear is more likely to occur during a knee injury. cruciate ligament with Mechanoreceptors are responsible for detecting any changes in knee directional velocity and tension position. It is lined by synovial fluid that provides nourishment and plays an integral role in healing.
What is mucinous degeneration of the anterior cruciate ligament?
This is a rare pathological condition in which the signal within the ligament increases. Myxoid degeneration is an irreversible degeneration of tissue with infiltration of mucin (glycosaminoglycans) within fibers [1][2]. Several theories have been proposed to explain Pathological disintegration of the collagen fibers of the anterior cruciate ligament, such as synovial trauma and “degenerative synovium” theory – pointing to an accumulation of synovial fluid inside the ACL substance in the protruding synovial pocket. Trauma” theory – post Injured ACL fibroblasts secrete glycosaminoglycans, the mucinous substances within the ACL. Other theories include the “degenerative” theory – MD may occur due to aging. [3]
Clinical Findings
- Painful terminal knee flexion[2][3]
- Stiffness[2]
- No instability[2][3]
- No extension block[3]
- Joint line tenderness[3]
- Swelling[3]
- Crepitation[3]
- Posterior knee pain[3][4]
- Difficulty in sitting and squatting cross-legged when climbing stairs[5]
Causes
- Acute/Repeated Trauma[4][6]
- Ageing
- Special conditions- Osteoporosis destroys menisci meniscal tear[3] Meniscectomy[4].
Complications
- Local smooth muscle thrombosis[3].
- Ganglionic cyst
- Tendon tear/ Tendon rupture
Radiological Findings
MRI
- Characteristic: exposed celery stalk[4] shows ACL damage.
- Accumulation of ligaments and tendons by mucoid changes may manifest as a stiff and/or hypertrophied appearance with increased symptom intensity.[3][4]
- Narrowing of the intercondylar notch[5]
- ACL tears are sometimes false positive on MRI examination thus requiring investigation and histopathology to make a definitive diagnosis.[3][4]
Arthroscopy
- Arthroscopically the ACL is intact but fibrillated yellowish and hypertrophied with interspersed yellowish mucinous material around the fibers without synovial linning of the ACL[4].
Differential Diagnosis
Clinically similar conditions are:
- Ligament tear/Ligament rupture[4][5]
- Fatty infiltration[4][5]
- Ligament sprain[5]
- Ganglion cyst[2]
Treatment
Conservative
NSAIDS and Physiotherapy[6]
Surgical
- Partial/Total ACL resection arthroscopically- There is a marked improvement in the range and a decrease in postoperative pain but at a higher cost as postoperative knee weakness increases.[3][4][6]has in some cases and can lead to instability. The prognosis depends on the patient’s age and associated features supports[2] .
- Arthroscopic debridement[4]
- Notchplasty[3][6]
Postoperative Rehabilitation
- Wear knee brace[5]
- Partial weight bearing is initially allowed.[5]
- ACL reconstruction procedures are followed.[3][5]
References
- ↑ Palmer W, Bancroft L, Bonar F, Choi JA, Cotten A, Griffith JF, Robinson P, Pfirrmann CW. Glossary of terms for musculoskeletal radiology. Skeletal Radiology. 2020 Jun 2.
- ↑ Jump up to:2.0 2.1 2.2 2.3 2.4 2.5 el Kadi KI, Marcaillou F, Blanc S, Salloum B, Dimontagliari C, Boutayeb F. Mucoid degeneration of the anterior cruciate ligament: a case report. Pan African Medical Journal. 2013;15(1).
- ↑ Jump up to:3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 Pandey, Vivek et al. “Mucoid degeneration of the anterior cruciate ligament: Management and outcome.” Indian journal of orthopaedics vol. 48,2 (2014): 197-202. doi:10.4103/0019-5413.128765
- ↑ Jump up to:4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Lintz F, Pujol N, Dejour D, Boisrenoult P, Beaufils P. Anterior cruciate ligament mucoid degeneration: selecting the best treatment option. Orthopaedics & Traumatology: Surgery & Research. 2010 Jun 1;96(4):400-6.
- ↑ Jump up to:5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Loganathan D, Soma Sundar S, Sundar S, Sahanand S, Rajan DV. Mucoid degenerated anterior cruciate ligament (ACL) managed by arthroscopic ACL reconstruction: A case series. International Journal of Orthopaedics. 2018;4(4):875-80.
- ↑ Jump up to:6.0 6.1 6.2 6.3 Lintz F, Pujol N, Boisrenoult P, Bargoin K, Beaufils P, Dejour D. Anterior cruciate ligament mucoid degeneration: a review of the literature and management guidelines. Knee Surgery, Sports Traumatology, Arthroscopy. 2011 Aug 1;19(8):1326-33.
