Many studies have reported on clinical outcomes after meniscal repair, but these studies usually included the patients with and without ACL injury. Only a few studies have specifically targeted cases of meniscal repair with concurrent ACLR. At early follow-up (2 years), high success rates have been reported (90–96 %) [40, 43], whereas long-term studies show a decline in success rates with time [24, 44]. Long-term outcomes after meniscal repair in patients undergoing concurrent ACLR are limited to case series, with failure rates ranging from 0 % to 29 % at a minimum of 5 years of follow-up [24, 28, 38]. A recent systematic review calculated the failure rate of meniscal repair with ACLR to be 26.9 % at 5 years [32]. In addition to these studies, those that have assessed prognostic factors affecting the outcomes of meniscal repair with concomitant ACL injury have been published. Generally, tear location and joint stability are factors that affect meniscal healing [8, 37, 44]. However, other factors such as tear length and pattern, patient age, repair technique, and chronicity of the injury may also affect healing [5, 37, 44].

With respect to tear location, meniscal repair of red-red and red-white tears is associated with acceptable short- and midterm clinical healing rates with or without ACLR. Although limited information regarding meniscal repair in avascular regions exists, white-white tears had a lower rate of complete meniscal healing when evaluated by second arthroscopy than red-red or red-white tears in short-term follow-up studies [2, 8].

In ACL-insufficient knees, microdamage can explain increasing rates of medial meniscal lesions [37]. The rate of secondary meniscectomy after meniscal repair in unstable knees was higher than that in ACL reconstructed knees [38]. Most investigators noted that one of the most important factors for meniscal healing is the restoration of joint stability. This suggests the need to perform ACLR with anatomical tunnel placement in order to restore normal anterior laxity.

In a comparison of clinical outcomes of meniscal repair between ACL reconstructed, insufficient, and intact knees, outcomes for reconstructed knees were better [3, 17, 21, 23, 33]. There are three possible explanations for the improved success of meniscal repair with concurrent ACLR. First, drilling of tibial and femoral tunnels and the associated bleeding may promote a biologically favorable environment for meniscal healing [43]. Second, slower rehabilitation of patients undergoing ACLR promotes a low-force environment for the meniscus. Third, the tear pattern of meniscus with acute ACL rupture may be more amenable to repair [7, 32], whereas injured menisci in intact knees are more commonly degenerative [12, 31].

Although grafts used for ACLR do not significantly influence the failure rate of meniscal repair, the condition of the transplanted graft affects the outcome of the repaired meniscus. Indeed, a large proportion of meniscal failures (27.3 %) are associated with ACL graft failure [44].

Progress has been made recently in surgical strategies for meniscal repair, which have substantially improved clinical outcomes. Yet, some negative prognostic factors exist for meniscal healing in cases of ACLR. Considering the importance of restoring knee joint kinematics for facilitating meniscal healing environment following ACLR, it is likely important to consider anatomical reconstruction of the ACL.