High short-term return to sports rate despite an ongoing healing process after acute meniscus repair in young athletes.

Acute meniscus repair in young athletes is always a challenge due to the long rehabilitation process and time to return to sport (RTS). The purpose was to investigate signal alterations in short-term follow-up after acute meniscus repair on specific magnetic resonance imaging (MRI) scan sequences. It was hypothesized that (1) MRI signal changes over the first postoperative healing phase and represent a continuous healing process and (2) meniscus healing properties correlates with clinical outcomes and RTS. Young athletes with traumatic meniscus lesion and arthroscopic meniscus repair within 6 weeks and available preoperative MRI were enrolled. Clinical examination, outcome scores (IKDC, KOOS, Lysholm Score, Tegner activity score) and RTS were surveyed preoperatively and 6 and 12 weeks and 6 months after surgery. Radiological follow-up examinations were performed 2, 4, 6, 12 weeks and 6 months after operation using a 3T-MRI. Evaluation was based on ISAKOS meniscus classification system, meniscus healing were classified according to Henning's criteria. At final follow-up (FU) 30 patients (28 month, 2 week) with a total of 35 meniscus tears (19 medial, 16 lateral) were included. Clinical scores improved significantly after surgery: IKDC Score (preOP: 39.4 ± 18.5, final FU: 78.8 ± 15.3) KOOS (preOP: 45.7 ± 22.1, final FU: 82.7 ± 12.5) and Lysholm Score (preOP: 42.8 ± 23.7, final FU: 84.4 ± 13.8) (p < 0.01). Tegner activity score showed a steadily increase to 4 (range 3-9) at 6 months but did not reached the pre-injury level of 6 (range 3-9). RTS rate was 100% whereof 44.8% reached their pre-injury level. MRI examination revealed a continuous healing process and menisci were classified as 55.9% healed, 35.3% partially healed and 8.8% non-healed at final FU. This study showed that MRI signal alterations of the meniscus steadily occur within the first 6 months postoperatively. MRI reveals an ongoing healing process at final FU that have to be carefully considered when RTS is discussed with high demanding patients. However, young athletes provide good clinical results and RTS rate even though MRI alterations are still present. Therapeutic study, prospective case series, Level IV.