Accuracy of cup placement compared with preoperative surgeon targets in primary total hip arthroplasty using standard instrumentation and techniques: a global, multicenter study.

BACKGROUND: Acetabular cup positioning in total hip arthroplasty (THA) is closely related to outcomes. The literature has suggested cup parameters defined by the Lewinnek safe zone; however, the validity of such measures is in question. Several studies have raised concerns about the benefits of using the Lewinnek safe zone as a predictor of success. In this study we elected to use prospective surgeon targets as the basis for comparison to see how successful surgeons are positioning their cup using standard instruments and techniques. METHODS: A prospective, global, multicenter study was conducted. Cup positioning success was defined as a composite endpoint. Both cup inclination and version needed to be within 10° of the surgeon target to be considered a success. Radiographic analysis was conducted by a third-party reviewer. RESULTS: In 170 subjects, inclination, target versus actual, was 44.8° [standard deviation (SD 0.9°)] and 43.1° (SD 7.6°), respectively (p = 0.0029). Inclination was considered successful in 84.1% of cases. Mean version, target versus actual, was 19.4° (SD 3.9°) and 27.2° (SD 5.6°), respectively (p < 0.0001). Version was considered successful in 63.4% of cases, and combined position (inclination and version) was considered successful in 53.1%. CONCLUSION: This study shows that with traditional methods of placing the cup intraoperatively, surgeons are only accurate 53.1% of the time compared with a predicted preoperative plan. This study suggests that the inconsistency in cup positioning based on the surgeon's planned target is potentially another important variable to consider while using a mechanical guide or in freehand techniques for cup placement in THA. TRIAL REGISTRATION: This study is registered on ClinicalTrials.gov, NCT03189303.

Early functional recovery outcomes and return to work after primary total hip arthroplasty: a novel patient reported outcomes questionnaire.

PURPOSE: Clinical and patient reported outcomes are often collected before and after the procedure to benchmark and study outcomes for patients. These outcomes and scores are useful for tracking patient outcomes after surgery, however, the fact that these commonly used measures typically provide information about a patient's level of pain and function at a single point in time is a limitation. METHODS: We present early functional recovery and return to work outcomes after primary THA from a novel questionnaire administered in a global, multi-center, prospective clinical study. RESULTS: By 6 and 12 weeks post-op, a large proportion of study subjects were able to perform functional recovery outcomes after their THA: walk without an aid (74%; 94%); drive (76%; 97%); basic activities of daily living (94%; 99%); perform light household duties (91%; 96%); perform moderate-to-heavy household duties (54%; 86%); go up and down a flight of stairs (92%; 99%); put on socks/stockings (77%; 93%); bend down to pick up an object from the floor (87%; 97%); stand up from a chair (96%; 99%); perform leisure recreational activities (54%; 84%); perform primary goal identified pre-THA (69%; 86%). 60% were able to return to work by 12 weeks post-op. These questions showed strong association with the Forgotten Joint Score. CONCLUSION: Excellent patient reported early functional recovery outcomes and satisfaction were observed at 6- and 12-weeks post-op in this cohort and is the first reported data using a novel PRO. CLINICAL TRIAL REGISTRATION: NCT03189303, registered June 14, 2017.

Use of an Automated Surgical Impactor Reduces Femoral Broaching Time in Direct Anterior Approach Total Hip Arthroplasty: Results From a Randomized, Multicenter Study.

Background: Impaction in total hip arthroplasty has typically been conducted using a mallet. A surgical automated impactor has been developed with the goal of reducing surgeon variability, fatigue, and injury. There is also potential to reduce the variability of each impaction step in which automated impaction is used, through reproducible and consistent application of force. Methods: Patients were randomized into either the mallet control group, or the automated impaction study group (1:1 randomization). The primary endpoint analysis was conducted to demonstrate that femoral broaching time (in minutes) with an automated impactor is noninferior to femoral broaching time with manual instruments (mallet) under a noninferiority (NI) margin of 1.25 minutes, with a subsequent test of superiority. A total of 218 patients were randomized and treated (109 in each group). Results: Mean femoral broaching time was 5.8 minutes in the automated impaction study group (automated), and 8.1 minutes in the mallet control group (mallet), a 28.4% reduction (P = .0005). However, there was not a difference in surgery duration between the groups. Three fractures were reported in the mallet group and 1 in the automated group. Conclusions: In this randomized multicenter study, an automated impactor was shown to reduce femoral broaching time in primary total hip arthroplasty, with no increase in fractures, but no decrease in operating room time was noted.