Title: Dancing with Discoid Meniscus
Name: Mari Mathers
Primary Presenters: Mari C Mathers
College of Health Sciences
Masters
Faculty Sponsor(s): Ericksen, H. M.

Dancing with Bilateral Discoid Meniscus: A Level 4 Case Study
Mathers MC., Ericksen HM: University of Wisconsin-Milwaukee, Milwaukee, Wisconsin

Background: A 25-year-old male dancer for a professional ballet company presented to the athletic training room with right lateral knee pain rated 2/10. The dancer was slowly lunging to the ground with most of his weight on the right leg when he felt and heard a pop in the lateral knee. The patient reported that his right knee felt “click-ie” and stuck. He felt strong and stable while dancing and performing manual muscle tests but when rising from a deep squat he could not straighten his knee. History revealed that the patient was diagnosed with bilateral lateral discoid meniscus at childhood and had since undergone three left knee surgeries and one right knee surgery. Discoid meniscus is an anatomical congenital anomaly causing the meniscus to be a thicker, wider, more oval shaped than normal. The initial assessment by the athletic trainer (AT) discovered no pain or reproduction of symptoms upon palpation. Both meniscus and iliotibial band (ITB) special tests were positive including McMurray’s test for clicking, Thessaly’s test for getting stuck in flexion, and Ober’s for tightness. Initial assessment concluded right ITB tightness and irritation with suspected meniscal tear noted for follow up.

Differential Diagnosis: meniscus tear, popliteus irritation, ITB irritation w/ biceps femoris involvement.
Treatment: Initial treatment included a home program and soft tissue treatment to release the tensor fascia late (TFL), lateral quadricep, lateral hamstring, and lateral glute with the goal to decrease tension and irritation on the ITB. Reassessment three days later revealed more frequent knee locking, decreased pain, and decreased ITB tightness. The patient was assessed by the team physician and diagnosed with popliteus irritation with potential ITB and biceps femoris involvement, however the patient’s symptoms kept progressing. A MRI was ordered and horizontal tears in both the lateral meniscus body and medial meniscus posterior horn were found, as well as a suspected horizontal tear of the lateral meniscus body. The patient met with the team surgeon and was scheduled for a meniscus debridement 35 days after the initial injury. Surgery revealed tears on the medial meniscus and degeneration of the lateral meniscus. The medial tears were cleaned up during the procedure, however the lateral degeneration was unable to be addressed. Physical therapy began 42 days after initial injury and continued two times per week for 2 months. The dancer successfully returned to performance four months after initial injury with mild occasional pain and lateral knee locking due to degeneration.
Uniqueness: This case of meniscal tear is unique due to the chronic complications of discoid meniscus in a professional ballet dancer. The incidence of discoid lateral meniscus is estimated to be between 0.4% to 17%. This patient diagnosed with discoid meniscus at childhood has maintained a professional career due to choreography modifications, surgery, physical therapy, and home exercise programs despite the abnormal shape of discoid meniscus increasing the likelihood of injury. This patient had been dancing for 20 years, three of those professionally. Although the patient had undergone multiple debridement’s in the past, the issue of right lateral knee locking, and pain was unable to be completely resolved due to early degeneration from the congenital anomaly.
Conclusion: Discoid meniscus is a unique condition that may not be seen often but is important to understand. Although patient tested positive for meniscal tear in a clinical exam, the surgical debridement is likely unable to completely resolve the symptoms due to the chronic nature of the condition. As a clinician conducting evaluation and treatment of a patient with discoid meniscus it is important to place high importance on rehabilitation, exercise programming, and working around the locking symptom.

https://sites.uwm.edu/healthresearchsymposium-2022/files/formidable/2/References-1d9232.pdf