Comparison of short-term outcomes of anterolateral supine approach and posterolateral approach for primary total hip arthroplasty: a retrospective study

BACKGROUND: This study aims to evaluate postoperative pain and functional and clinical outcomes of anterolateral supine (ALS) and posterolateral (PL) approaches for primary total hip arthroplasty. MATERIALS AND METHODS: We retrospectively examined the joints of 110 patients who underwent primary total hip arthroplasty (THA). The ALS group was compared with the PL group using the pain visual analog scale (VAS) and narcotic consumption as pain outcomes. Functional outcomes included postoperative range of motion (ROM) of hip flexion, day on which patients could perform straight leg raising (SLR), day on which patients began using a walker or cane, duration of hospital stay, rate of transfer, and strength of hip muscles. Clinical outcomes included pre and postoperative Harris Hip Scores. RESULTS: No significant differences were found in the pain VAS scores or narcotic consumption between the two groups. The PL group could perform SLR earlier than the ALS group (P < 0.01). The ALS group started using a cane earlier (P < 0.01) and had a shorter hospital stay (P < 0.01) than the PL group. Degrees of active ROM of flexion at postoperative day (POD) 1 were significantly lower in the ALS group than in the PL group (P < 0.01). Regarding hip muscle strength, hip flexion was significantly weaker in the ALS group than in the PL group until 1-month POD (P < 0.01). External rotation from 2 weeks to 6 months postoperatively was significantly weaker in the PL group than in the ALS group (P < 0.01). CONCLUSION: The ALS approach was more beneficial than the PL approach because ALS enabled better functional recovery of the strength of external rotation, improved rehabilitation, and involved a shorter hospital stay. LEVEL OF EVIDENCE: Level IV retrospective observational study.