title: Improved Functional Outcomes with Robotic Compared with Manual Total Hip Arthroplasty.
abstract: BACKGROUND
  Functional outcome following total hip arthroplasty (THA) is affected by accurate component positioning and restoration of hip biomechanics. Robotic-assisted THA (rTHA) has been shown to improve accuracy of component positioning, but its impact on functional outcomes has not been demonstrated. The purpose of this study was to compare: 1) operative time; 2) estimated blood loss; 3) postoperative complications; and 4) patient-reported outcome measures (PROMs) between patients who either underwent rTHA or manual THA (mTHA).
  
  
  METHODS
  In this retrospective cohort study, a single-center database was used to identify all patients who underwent primary THA since introduction of rTHA at a large academic medical center. Surgical factors including operative time and estimated blood loss as well as postoperative complications were recorded. Validated PROMs following rTHA (n = 100) were compared with consecutive mTHA cases (n = 100) performed by the same fellowship-trained surgeon at a minimum one-year follow-up (24 ± 6 months). PROMs included the Short-Form 12 Health Survey (SF-12), UCLA activity score (UCLA), Western Ontario and McMaster (WOMAC) Osteoarthritis Index, and modified Harris Hip Score (mHHS). A categorical analysis was performed to determine differences in proportions of patients with mHHS scores of 90 to 100, 80 to 89, 70 to 79, and < 70 points between the two groups. Chi-square and two-tailed t-tests were used to compare categorical and continuous data between cohorts.
  
  
  RESULTS
  Mean operative time was nine minutes longer for the rTHA group compared with the mTHA group (131 ± 23 min vs. 122 ± 29 min, respectively, p = 0.012). Estimated intraoperative blood loss was significantly reduced for the rTHA group when compared to the mTHA group (374 ± 133 mL vs. 423 ± 186 mL, p = 0.035), and there was no difference in overall complication rates between the two groups (p = 0.101). Robotic-assisted THA demonstrated significantly higher mean postoperative mHHS (92.1 ± 10.5 vs. 86.1 ± 16.2, p = 0.002) and mean UCLA scores (6.3 ± 1.8 vs. 5.8 ± 1.7, p = 0.033) compared with mTHA. The difference between pre- and postoperative mHHS scores was statistically significant when comparing rTHA with mTHA (43.0 ± 18.8 vs. 37.4 ± 18.3, p = 0.035). There were no significant differences in SF-12 or WOMAC scores. There was a significantly higher proportion of patients with mHHS scores between 90 to 100 points (75% vs. 61%, p = 0.034) and a lower percentage with scores < 70 points (6% vs. 19%, p = 0.005) in the rTHA cohort compared with the mTHA cohort.
  
  
  CONCLUSIONS
  The rTHA cohort demonstrated significantly higher mean postoperative UCLA scores, higher mean postoperative mHHS scores, and a greater percentage of patients with mHHS of 90 to 100 points compared with mTHA at a minimum one-year follow-up. To our knowledge, this is the first study to demonstrate that robotic-assisted THA leads to improved patient-reported outcomes. The observed improvement in functional outcomes following rTHA is encouraging and warrants additional multi-center studies to determine if these advantages are maintained at longer follow-up intervals.
authors.affiliation: Department of Orthopedics and Rehabilitation, The University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Bukowski
authors.affiliation: Department of Orthopedics and Rehabilitation, The University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Paul
authors.initials: P
authors.lastname: Anderson
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Anton
authors.initials: A
authors.lastname: Khlopas
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Morad
authors.initials: M
authors.lastname: Chughtai
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mont
authors.affiliation: Department of Orthopedics and Rehabilitation, The University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Illgen
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D006801:Humans; D012086:Reoperation; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures; D016896:Treatment Outcome