A Case Report & Literature Review

Regeneration of a Discoid After Arthroscopic Saucerization

Matthew I. Stein, MD, Roger B. Gaskins III, MD, Charles C. Nalley, MD, and Charles Nofsinger, MD

regenerating after saucerization. In this article, we describe Abstract the case of a 5-year-old girl who presented to the clinic with We report the case of a 5-year-old girl who recurrent pain after meniscal repair and saucerization presented to the clinic with recurrent at age 3. The finding of a regenerated discoid meniscus was after meniscal repair and saucerization at age 3. confirmed both arthroscopically and radiographically. To our The finding of a regenerated discoid meniscus knowledge, this is the first report in the literature to confirm was confirmed arthroscopically and radiographi- regeneration of a discoid meniscus after saucerization. The case cally. To our knowledge, this is the first report in has significant implications for management of pediatric dis- the literature to confirm regeneration of a discoid coid meniscus tears and patient counseling and is encouraging meniscus after saucerization. The case has sig- in terms of the potential for repair and regeneration of menis- nificant implications for management of pediatric cal tissue, particularly in the very young pediatric population. discoid meniscus tears and patient counseling, The patient’s family provided written informed consent for and is encouraging in terms of the potential for print and electronic publication of this case report. repair and regeneration of meniscal tissue, par- ticularly in the very young pediatric population. Case Report A 3-year-old girl was initially presented to her primary care AJOprovider with acute onset of left knee “clicking” and pain with ambulation. Symptoms began the preceding morning, though iscoid meniscus is an abnormality in which the car- the patient did not recall an inciting event, and they progressed tilaginous meniscus is shaped like a disc and is thick- over the next several weeks, at which point she was referred Dened, covering more of the . This finding was to the clinic for evaluation. first described by Young,1 after a cadaveric dissection, in 1887. Initial physical examination revealed a slightly antalgic gait. Discoid meniscus occurs most often in the lateral compart- On focused examination of the left lower extremity, the left ment,DO and is often asymptomatic, NOT which makes the true in- knee madeCOPY an audible “pop” when brought into full exten- cidence and prevalence of this abnormality difficult to deter- sion. The ligaments were stable and there was no joint effu- mine. Discoid menisci are classified according to arthroscopic sion. There was mild tenderness to palpation over the lateral morphology (complete or incomplete) and stability (stable or joint line and significant irritation was noted on the McMurray unstable).1,2 The Watanabe classification, which is most com- circumduction test. monly used, notes 3 lateral discoid variants. Type I (complete Magnetic resonance imaging (MRI) findings for the left discoid meniscus) and type II (partial discoid meniscus) are knee were consistent with a discoid and an block-shaped and generally stable to probing with normal associated small central meniscus tear. These conditions were peripheral attachments. Type III discoid menisci lack posterior thought to be causing the patient’s discomfort, and arthroscop- meniscal attachments, including the meniscotibial ligaments; ic saucerization with possible meniscal repair was scheduled. the only stabilizing ligament in a type III discoid meniscus is During arthroscopy, an obvious complete discoid lateral the ligament of Wrisberg, and as such, this variant is often meniscus was noted. It was grossly unstable, consistent with referred to as the Wrisberg variant.1,2 a Wrisberg variant (Figures 1A, 1B). Arthroscopic sauceriza- Surgical intervention is indicated for symptomatic discoid tion and repair were performed (Figure 1C). An inside-out menisci, often after a tear of the thickened, abnormal tissue.1,3,4 technique was used to repair the meniscal body tear, and an Currently, most authors recommend meniscal preservation all-inside FiberWire FasT-Fix (Smith & Nephew Inc, Endoscopy with arthroscopic saucerization supplemented by meniscal Division, Andover, Massachusetts) technique was used to reat- repair as appropriate. Total meniscectomy is generally avoided tach the posterior horn to the posterior capsule. in children.2 Initially, the patient fared well after surgery. Physical ther- The literature lacks current reports of a discoid meniscus apy was initiated, and weight-bearing was limited for several

Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article. www.amjorthopedics.com January 2013 The American Journal of Orthopedics®5 E Regeneration of a Discoid Meniscus After Arthroscopic Saucerization M. I. Stein et al

A B C

Figure 1. Arthroscopic images from original surgery. (A, B) Discoid meniscus obvious on arthroscopic examination; subsequent probing allowed for subluxation of meniscus into intercondylar notch, indicating meniscus instability. (C) Arthroscopic saucerization and repair.

A B C AJO

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Figure 2. Magnetic resonance imaging before second arthroscopy. (A-C) T2-weighted scans show 3 consecutive sagittal cuts, with bow- tie sign of lateral meniscus confirming diagnosis of discoid meniscus. (D-F) Coronal T2-weighted scan shows block-shaped morphology of lateral meniscus.

weeks. At the 4-week clinic visit, there was full range of mo- and no popping or snapping in the knee. Two and a half years tion with no audible popping or snapping in the knee. The after initial presentation, she took a ground-level fall onto her patient was ambulating without assistance. She returned to full bent left knee. She experienced pain and swelling and could activity over the next several weeks. not extend the knee. MRI again revealed the characteristic find- Over the next 2 years, the patient returned to participating ings of a discoid meniscus, including bridging of the anterior in activities like competitive soccer and tennis. She had no pain and posterior horns on 3 continuous sagittal sections (Figure

E6 The American Journal of Orthopedics® January 2013 www.amjorthopedics.com Regeneration of a Discoid Meniscus After Arthroscopic Saucerization M. I. Stein et al

A B C

Figure 3. Repeat arthroscopy shows evidence of regenerated discoid lateral meniscus. (A) Regenerated tissue appears characteristic of discoid meniscal tissue. (B) Further examination reveals detachment of lateral meniscus and obvious instability. (C) Repeat saucerization and repair.

2A-F). MRI also showed evidence of a recurrent tear in the cal outcomes in the short to intermediate term.8,9 Therefore, anterior horn of the lateral meniscus. The patient underwent there is seldom an indication for repeat arthroscopy in pedi- a trial of nonoperative care. Several weeks later, she presented atric patients. to the clinic with a locked left knee and was scheduled for Although the radiographic and arthroscopic findings of repeat arthroscopy. our patient’s second arthroscopy confirmed a diagnosis of a This arthroscopic examination revealed what appeared discoid meniscus, it would be interesting to know the micro- to be grossly normal meniscal tissue regenerated in the area scopic composition of the regenerated tissue. On arthroscopic of the previous saucerization, recreating a discoid meniscus examination, the regenerated tissue was characteristic of (Figure 3A). On further probing and study, the regenerated tissue normal meniscal tissue, in appearance as well as texture and appeared to be characteristic of normal meniscalAJO tissue. In addi- thickness. Microscopic examination would likely have con- tion, a tear was identified in the lateral compartment. The later- al meniscus was again saucerized and repaired (Figure 3B, 3C) using a similar technique. The postoperative course was unremarkable. One year after “To our knowledge, this is the first case the second arthroscopy, the patient returned to her normal activities. report to present both radiographic and DO NOTarthroscopic COPY evidence of a regenerated Discussion To our knowledge, this is the first report in the literature to discoid lateral meniscus [and] to identify present both radiographic and arthroscopic evidence of a regeneration of a previously saucerized regenerated discoid lateral meniscus. The incidence of discoid meniscus is difficult to determine, as most patients remain discoid meniscus.” asymptomatic. However, current estimates suggest a discoid meniscus in 3% to 5% of the population.5 Given the pre- ponderance of asymptomatic cases, the literature addressing outcomes of surgical intervention for symptomatic discoid firmed normal fibrocartilaginous tissue, but in retrospect, it menisci is fairly limited and the patient cohorts are relatively would have been especially instructive to have the tissue ex- small.1,2,6,7 amined histologically. Nevertheless, this case has significant Much of the literature on outcomes of surgical intervention relevance and implications for the study of meniscal repair in this patient population has focused on the long-term risk and regeneration after meniscal injury, particularly in the for developing and osteochondral defects.8,9 To pediatric population. our knowledge, no study has outlined the arthroscopic find- To our knowledge, this is also the first case report to identify ings in patients who previously underwent saucerization— regeneration of a previously saucerized discoid meniscus. The specifically, findings of evidence of regeneration. In addition, regenerated discoid meniscus may have made our patient more recurrent meniscal tears in the pediatric population are rare.10 susceptible to the recurrent meniscal tear. Young patients and Under these conditions, it is difficult to determine how their families should be counseled regarding the potential for prevalent a regenerated discoid meniscus might be in the a recurrent discoid meniscus after saucerization. Researchers pediatric patient population. Discoid menisci are rare, most should try to determine if this finding is more prevalent than remain asymptomatic and many patients have excellent surgi- previously thought.

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Dr. Stein is Resident Physician, Department of Orthopaedics and 3. Albertsson M, Gillquist J. Discoid lateral menisci: a report of 29 cases. Sports Medicine, University of South Florida, Tampa. Dr. Gaskins Arthroscopy. 1988;4(3):211-214. is Research Intern, Foundation for Orthopaedic Research and 4. Dickhaut SC, DeLee JC. The discoid lateral-meniscus syndrome. J Bone Education, Tampa, Florida. Dr. Nalley is Resident Physician, and Dr. Joint Surg Am. 1982;64(7):1068-1073. Nofsinger is Attending Physician, Department of Orthopaedics and 5. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic Sports Medicine, University of South Florida, Tampa. resonance images of asymptomatic . J Orthop Sci. 2002;7(3):287-291. 6. Atay OA, Doral MN, Leblebicio lu G, Tetik O, Aydingöz U. Management Address correspondence to: Matthew I. Stein, MD, Department ğ of discoid lateral meniscus tears: observations in 34 knees. Arthroscopy. of Orthopaedics and Sports Medicine, 13220 USF Laurel Dr, MDF 2003;19(4):346-352. 5th Floor, Mail Code MDC 106, University of South Florida, Tampa, 7. Wasser L, Knörr J, Accadbled F, Abid A, Sales De Gauzy J. Arthroscopic FL 33613 (tel, 813-396-9639; fax, 813-396-9195; e-mail, mstein@ treatment of discoid meniscus in children: clinical and MRI results. Or- health.usf.edu). thop Traumatol Surg Res. 2011;97(3):297-303. Am J Orthop. 2013;42(1):E5-E8. Copyright Frontline Medical Com- 8. Rao SK, Sripathi Rao P. Clinical, radiologic and arthroscopic assessment munications Inc. 2013. All rights reserved. and treatment of bilateral discoid lateral meniscus. Knee Surg Sports Traumatol Arthrosc. 2007;15(5):597-601. 9. Okazaki K, Miura H, Matsuda S, Hashizume M, Iwamoto Y. Arthroscopic References resection of the discoid lateral meniscus: long-term follow-up for 16 1. Kramer DE, Micheli LJ. Meniscal tears and discoid meniscus in children: years. Arthroscopy. 2006;22(9):967-971. diagnosis and treatment. J Am Acad Orthop Surg. 2009;17(11):698-707. 10. Hayashi LK, Yamaga H, Ida K, Miura T. Arthroscopic meniscec- 2. Bellisari G, Samora W, Klingele K. Meniscus tears in children. Sports tomy for discoid lateral meniscus in children. J Bone Joint Surg Am. Med Arthrosc. 2011;19(1):50-55. 1988;70(10):1495-1500.

This paper will be judged for the Resident Writer’s Award. AJO DO NOT COPY

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