The Effect Of Orbicularis Ligament Repair On The Dislocation Rate Of Hemiplegia Patients After Hemiarthroplasty

Objective:To explore the methods to reduce the dislocation rate after hemiarthroplasty(HA)in patients with femoral neck fractures(FNF)with lower extremity muscle strength≤grade 3.Methods:A retrospective analysis of 278 patients who underwent bipolar hemiarthroplasty for femoral neck fractures in the First Affiliated Hospital of Shandong First Medical University from January 2018 to June 2021.A total of 78 patients who were lost to follow-up(47 cases)and those with postoperative survival time less than 6 months(31 cases)were excluded.200 patients were divided into two groups according to the muscle strength of the affected limbs:group A≥grade 4(145 cases)and group B≤grade 3(55 cases).The two groups were divided into joint capsule protection and repair subgroup A1(n=36),B1(n=23)and unrepaired subgroup A2(n=109)and B2(n=32).The postoperative dislocation rate,Harris hip function score at the last follow-up and postoperative complications were observed in each group.Results:The dislocation rate in group A was significantly lower than that in group B(P=0.014).In the subgroup analysis,there was no significant difference in the dislocation rate between the A1 group and the unrepaired A2 group in the A group with muscle strength>4(P=0.574).The dislocation rate of group B1 repaired by joint capsule in group B with muscle strength ≤ 3 was significantly lower than that in group B2 without repair of joint capsule(P=0.032).The postoperative dislocation rate of group A1 and group B1 was 0%.There was no significant difference in postoperative dislocation rate between group A2 and group B2(P=0.005).In terms of postoperative modified Harris hip score(MHHS),the MHHS of group A with muscle strength>grade 4 was significantly higher than that of group B with muscle strength ≤ grade 3(P<0.001).In subgroup analysis,there was a statistically significant difference between group A1(84.08±7.36)and group B1(66.80±9.22)(P<0.001).Compared with group A2(81.46±9.15)and group B2(63.72±10.73),the difference was statistically significant(P<0.001).There were no significant differences in postoperative complications such as postoperative infection,lower extremity venous thrombosis,periprosthetic fractures,and chronic pain of unknown origin between the subgroups(all P values were greater than 0.05).Conclusion:The repair of orbicular ligament can significantly reduce the dislocation rate of hemiarthroplasty in patients with lower limb muscle strength≤grade 3 femoral neck fracture,and this technique will not increase the postoperative complications.However,the repair of orbicular ligament can’t improve the function of hip joint.