Are physical therapy pain levels affected by surgical approach in total hip arthroplasty? A randomized controlled trial

The main objective of this study was to evaluate the difference in pain levels during postoperative physical therapy pathways in patients who underwent a cement less total hip replacement either through a muscle sparing direct anterior approach (DAA), or the classic trans-gluteal lateral approach (LA). One hundred and twelve (112) patients were randomized into two equal groups. Baseline values of myoglobin levels were acquired prior to surgery and repeated at 6 hours postoperatively as a biomarker for muscle damage. Pain levels during the first passive and consecutive 3 active physical therapy sessions were noted using a visual analogue-numeric scale (VAS). Pain levels were also acquired at 6 weeks, 3 months, 6 months and 1 year, following a 20-meter (65.6 feet) walking test. Postoperative myoglobin (ng/mL) levels were significantly higher (p< 0.05) in the LA group (335.05 +/- 3.54) then the DAA group (237.71 +/- 57.54). Pain levels were significantly lower (p<0.001) in the DAA group for both passive (2.51 +/- 1.45 vs. 4.28 +/- 2.19) and active physical therapy sessions and there was a positive correlation between postoperative myoglobin levels and pain levels until 6 postoperative weeks. There was no significant difference in demographics between the two groups except for gender distribution. The direct anterior approach's main advantage of being a minimally invasive muscle sparing technique is showing a better rehabilitation experience with lower pain levels during passive and active physical therapy when compared to the classic trans-gluteal lateral approach.