To compare the efficacy of deficient and intact anterior cruciate ligament in treatment of unicompartmental knee arthroplasty(UKA)of the knee joint. Further explored whether the deficiency of the anterior cruciate ligament is one of the contraindications for UKA.

Databases of BioMedical Literature Database, China National Knowledge Infrastructure, WanFang Data, PubMed, Web of Science, Excerpta Medica Database(EMBASE)and Cochrane Library were searched for studies about the case-control literature on ACL-related UKA surgery from inception to April 2022. The literature that using other methods concurrently, no assessment of the ACL, irrelevant to the observation index or not accessed to the full-text were excluded. Two researchers strictly screened and evaluated the literature. The meta-analysis was performed by RevMan 5.4.

Twelve articles were enrolled in this study, including nine articles in English and three articles in Chinese. A total of 3177 knees were investigated, including 665 knees in the ACL deficient group and 2512 knees in ACL intact group. The meta-analysis showed that there was no statistically significant difference in the range of motion of the knee [ mean difference(MD)=-1.40, 95% confidence interval(CI)(-3.08, 0.29)], the rate of revision [ odds ratio(OR)=1.24, 95% CI(0.82, 1.89)], the posterior slope of the tibial implant [ standard mean difference(SMD)=-0.39, 95% CI(-0.51, -0.40)], the Hospital for Special Surgery(HSS)score [ MD=-0.47, 95% CI(-4.33, 3.39)], the Oxford Knee Score(OKS) [ MD=-0.21, 95% CI(-1.42, 1.01)] and the Tenger score [MD=-0.09, 95% CI(-0.39, 0.20)] between the two groups (P>0.05). In the valgus angle of the knee [SMD=-0.39, 95% CI(-0.64, -0.13)], the ACL deficient group was superior to ACL intact group (P =0.003, P < 0.05).

ACL deficiency is defined as that the ligament can not maintain normal tension or be pulled off after being forcibly pulled with a small hook during the operation. The mid-term and long-term efficacy of such patients after the operation is similar to that of the ACL intact group. ACL deficiency may not be one of the contraindications for UKA.