The intraoperative use of a calliper predicts leg length and offset after total hip arthroplasty. Component subsidence influences the leg length

Abstract Background The purpose of total hip arthroplasty (THA) post-surgery and proper physiotherapy is positive recovery for the patient. Consideration is given to hip replacement biomechanics by ensuring no discrepancies in limb length (LL) and a stable prosthesis. Therefore, the patient must have proper preoperative planning and communication and a clear understanding of what to expect. Methods A prospective series of 59 THA operated by a single surgeon via Hardinge approach was studied, using an intraoperative calliper (CAL) to predict the change of LL and offset. We compared the results of the intraoperative changes before and after THA implantation with the reference of these values on anteroposterior x-ray pelvis. The importance of leg length balance and a good offset restoration is questioned, and the effect of component subsidence on leg length is considered. Results The average preoperative leg length discrepancy was −6.0 mm, postoperatively +3.6 mm. There was a strong correlation between the CAL measurements and the values on the x-ray (LL, r=0.873, p<0.01; offset, r=0.542, p