There are few long-term outcome studies for arthroscopic saucerization. In 2014, Ahn and colleagues38 examined patient-reported outcomes and radiographic changes for 48 knees in pediatric patients treated arthroscopically for a symptomatic discoid meniscus. Patients were treated with partial meniscectomy (22 knees), partial meniscectomy with meniscal repair (18 knees), or subtotal meniscectomy (8 knees). Out of 48 knees evaluated, 45 knees (94%) were rated as “excellent” or “good” at an average 10-year follow-up. However, a significant percentage of patients had evidence of degenerative changes on follow-up radiographs, specifically: 88% of the subtotal meniscectomy group, 39% of the partial meniscectomy with repair group, and 23% in the partial meniscectomy-alone group. This finding suggests that the early appearance of radiographic changes suggestive of OA does not necessarily correlate with the development of knee symptoms in this cohort, although longer-term follow-up of these patients into adulthood and middle age is clearly needed.
Recently, short-term outcomes have been reported for contemporary arthroscopic saucerization of discoid menisci with peripheral rim stabilization performed as deemed necessary at the time of surgery. In 2012, Carter and colleagues39 examined 57 knees that underwent saucerization alone or saucerization with peripheral rim stabilization. At an average follow-up of 15 months, both patient populations had equivalent self-reported outcomes and clinical examination findings. The authors concluded that peripheral stabilization does not negatively affect short-term outcomes if instability is recognized and treated.
Yoo and colleagues40 found equivalent results between patients undergoing saucerization, saucerization with rim stabilization, and subtotal meniscectomy for 100 pediatric knees with an average follow-up of 4.7 years. Subtotal meniscectomy was defined as <3 mm of peripheral rim remaining and was performed when there was severe degeneration or complex tearing of the remnant rim following arthroscopic saucerization. Taken together, these data seem to suggest that short- and mid-term outcomes for pediatric patients treated surgically are generally good in terms of reported clinical function and development of OA, although long-term follow-up studies will be essential for understanding the true impact of surgical interventions.
Shieh and colleagues41,42 investigated risk factors for failed meniscal surgery in 324 menisci from 2008 to 2012, including in 46 discoid saucerization procedures with or without stabilization. At a mean of 40 months, 15% of the discoid saucerization cohort required a revision procedure, with increased odds of revision surgeries in patients who had undergone meniscal tear repair. The most frequent indication of revision surgery was sustaining a meniscal tear during intense physical activity in the first year after the index procedure, and patients underwent either debridement or repair for their revision procedure.
SUMMARY
Discoid meniscus is a rare anatomical meniscal variant characterized by an abnormal “O-like” shape, increased meniscal thickness, disorganization of collagen fibers, and variable absence of peripheral attachments. These morphological changes predispose patients with discoid menisci to increased rates of symptomatic meniscal instability and tearing. An MRI remains the most sensitive imaging modality for the diagnosis of a discoid meniscus, with ≥3 contiguous 5-mm sagittal cuts showing continuity between the anterior and posterior horns indicative of a discoid variant. Surgical treatment for symptomatic discoid menisci has evolved from subtotal meniscectomy to contemporary arthroscopic saucerization techniques with repair of meniscal tears and peripheral stabilization performed as needed. Long-term outcome studies for patients who undergo subtotal or complete meniscectomy reveal an association with osteoarthritic changes of the knee. Short- and mid-term outcome studies for patients who undergo arthroscopic saucerization with or without repair and/or peripheral stabilization are generally good, although reoperation rates have been estimated at 15% in the first 3 to 4 years. Longer-term follow-up, with the inclusion of validated functional outcomes measures, will be essential for understanding the true impact of various surgical interventions over time.