Relationship between Perceived Leg Length Discrepancy at One Month and Preoperative Hip Abductor Muscle Elasticity in Patients after Total Hip Arthroplasty

Abstract

Preoperative factors related to perceived leg length discrepancy (PLLD) after total hip arthroplasty (THA) are not well studied. This study aimed to examine the preoperative factors, including hip abductor modulus, related to PLLD one month after THA. Methods: The study included 73 patients diagnosed with osteoarthritis secondary to developmental dysplasia of the hip and a posterior approach to surgery. Multiple logistic regression analysis was performed using the presence or absence of PLLD as the dependent variable and preoperative hip abductor's modulus of elasticity, pain, hip abduction range of motion, hip abductor muscle strength and pelvic obliquity as the independent variable. Additionally, receiver operating characteristic curves were used for the extracted variables for calculating the cutoffs, sensitivity, specificity and area under the curve (AUC) to determine the presence or absence of PLLD. The significance level was set at p<0.05. Results: The hip abductor modulus (odds ratio=1.13; 95% confidence interval=1.06-1.21; p<0.001) was selected as a preoperative factor. The cutoff value to determine the presence or absence of a PLLD was 16.32 kPa. The sensitivity and specificity were 81.8% and 72.5%, respectively, and the AUC was 0.8137. Conclusion: The hip abductor muscle elastic modulus affected PLLD one month after THA. If the preoperative hip abductor elastic modulus is higher than the cutoff value, it may affect the appearance of PLLD at one month postoperatively.

Correlation analysis of clinical outcomes after THA in patients with pelvic skew

“…Standard and standardized imaging can provide good conditions for accurate measurement of bilateral lower limb length and pelvic skew; use a precise planning system to make the preoperative instrumentation preparation more adequate and accurate; do not blindly pursue the use of a higher FO prosthesis during surgery, because postoperative hip pain and function are also closely related to a higher FO [50] ; carefully and adequately check the soft tissue condition and condition of the affected hip joint before surgery, especially the muscle strength and atrophy of the gluteus medius and other adductor muscles, scienti cally assess the soft tissue tension, and can relieve the hip contracture by bone traction before surgery, and make the patient walk more on crutches on the healthy side to reduce the reaction force of the painful hip joint, so as to effectively correct the adductor muscle weakness gait secondary to hip pain, also called Trendelenburg gait; postoperative exercises should be performed to strengthen the contraction function of the hip and lower limb muscles in order to enhance muscle strength, which is more conducive to pelvic balance and functional recovery; intraoperatively, it is necessary to appropriately release the soft tissues, and in more severe Crowe III/IV DDH patients, subxiphoid osteotomy can be performed if necessary, but it is necessary to Della valle et al [51] concluded that unequal lower extremity lengths greater than 1 cm can lead to gait abnormalities and pelvic tilt, and that this increases the risk of prosthetic loosening; Plaass et al [52] concluded that if the patient's lower extremity length is not corrected after THA, the patient's hip function and Harris score will be compromised, and the results will not be as good as if the patient's lower extremity length is not corrected. A Japanese scholar [53] used a shear wave elastography ultrasound system to measure the preoperative hip abductor elasticity coe cient and found that if this elasticity coe cient exceeded a certain threshold value, it would affect the appearance of sensory lower limb inequality within 1 month after surgery. For example, hip abduction and adduction involve different muscles at the same time, and X-rays cannot depict and re ect the three-dimensional trajectory of skeletal muscle geometry, so there is a great limitation to accurately measure the abductor arm.…”