[Comparison of muscle injury between piriformis muscle release and preservation in total hip arthroplasty via supercapsular percutaneously-assisted total hip approach].

Abstract

Objective: To compare the effects of piriformis muscle release versus preservation in total hip arthroplasty (THA) via supercapsular percutaneously-assisted total hip (SuperPATH) approach on muscle injury.

Methods: Forty-nine patients undergoing initial THA via SuperPATH approach between June 2022 and June 2023 were randomly divided into two groups, with 24 patients in trial group and 25 patients in control group. The trial group received piriformis muscle release intraoperatively, whereas the control group underwent muscle preservation. There was no significant difference in baseline data such as gender, age, body mass index, disease type, American Society of Anesthesiologists (ASA) grading, and preoperative muscle infiltration, muscle atrophy, muscle injury serological indicators, Harris score, etc. ( P>0.05). The incision length, operation time, intraoperative blood loss, total blood loss, hospital stay, preoperative and postoperative 1-day muscle injury serological indicators [including creatine kinase (CK) and lactic dehydrogenase (LDH)], and incidence of complications between two groups were recorded. Harris score was used to evaluate the recovery of hip joint function. MRI was used to evaluate the extent of hip muscle injuries (gluteus minimus, gluteus medius, piriformis, obturator internus, quadratus femoris), including tendon integrity, degree of muscle fat infiltration, and degree of muscle atrophy preoperative and 1 year postoperatively.

Results: The operation time, intraoperative blood loss, and total blood loss in the trial group were significantly shorter than those in the control group ( P<0.05). There was no significant difference in the incision length and length of hospital stay between the two groups ( P>0.05). Both groups showed a significant increase in serum CK and LDH levels on postoperative day 1 compared to preoperative levels ( P<0.05), but there was no significant difference between the two groups ( P>0.05). All patients were followed up, the follow-up time for the trial group and the control group was (14.8±2.8) and (15.1±3.0) months, respectively, with no significant difference ( t=-0.400, P=0.691). Incisions healed by first intention in both groups, with 1 case in the trial group and 2 cases in the control group experiencing venous thrombosis in the calf muscle space. There was no complication such as deep vein thrombosis, pulmonary embolism, hip dislocation, prosthesis loosening, or periprosthetic infection in the lower limbs. There was no significant difference in the incidence of complications between the two groups ( P>0.05). At 1 year after operation, both groups of patients showed a significant increase in Harris scores compared to preoperative levels ( P<0.05), but there was no significant difference between the two groups ( P>0.05). Compared with preoperative results, both groups showed significant fat infiltration in the piriformis and obturator muscles at 1 year after operation ( P<0.05), while there was no significant fat infiltration in the gluteus minimus, gluteus medius, and quadratus femoris muscles ( P>0.05). At 1 year after operation, except for the higher incidence of piriformis muscle fat infiltration in the control group compared to the trial group ( P<0.05), there was no significant difference in the incidence of other muscle infiltrations between the two groups ( P>0.05). At 1 year after operation, both groups of piriformis and obturator muscles showed significant muscle atrophy compared to preoperative levels ( P<0.05). The gluteus minimus and gluteus medius showed mild atrophy compared to preoperative levels, while the maximum transverse diameter of the quadriceps muscle slightly increased, but the differences were not significant ( P>0.05). There was no significant difference in the maximum cross-sectional diameter or cross-sectional area changes of each muscle between the two groups ( P>0.05). At 1 year after operation, the continuity of the gluteus medius and quadratus femoris muscles in both groups was intact. Both groups had some patients with incomplete continuity of the piriformis muscle, obturator internus, and gluteus minimus, but the difference was not significant ( P>0.05).

Conclusion: The SuperPATH approach THA may cause injury to the piriformis, gluteus minimus, and obturator internus. The piriformis muscle release does not increase muscle injury, but it can shorten the operation time and reduce bleeding.