Stepping beyond Counts in Recovery of Total Knee Arthroplasty: A Prospective Study on Passively Collected Gait Metrics.

Advances in algorithms developed from sensor-based technology data allow for the passive collection of qualitative gait metrics beyond step counts. The purpose of this study was to evaluate pre- and post-operative gait quality data to assess recovery following primary total knee arthroplasty. This was a multicenter, prospective cohort study. From 6 weeks pre-operative through to 24 weeks post-operative, 686 patients used a digital care management application to collect gait metrics. Average weekly walking speed, step length, timing asymmetry, and double limb support percentage pre- and post-operative values were compared with a paired-samples t-test. Recovery was operationally defined as when the respective weekly average gait metric was no longer statistically different than pre-operative. Walking speed and step length were lowest, and timing asymmetry and double support percentage were greatest at week two post-operative (p < 0.0001). Walking speed recovered at 21 weeks (1.00 m/s, p = 0.063) and double support percentage recovered at week 24 (32%, p = 0.089). Asymmetry percentage was recovered at 13 weeks (14.0%, p = 0.23) and was consistently superior to pre-operative values at week 19 (11.1% vs. 12.5%, p < 0.001). Step length did not recover during the 24-week period (0.60 m vs. 0.59 m, p = 0.004); however, this difference is not likely clinically relevant. The data suggests that gait quality metrics are most negatively affected two weeks post-operatively, recover within the first 24-weeks following TKA, and follow a slower trajectory compared to previously reported step count recoveries. The ability to capture new objective measures of recovery is evident. As more gait quality data is accrued, physicians may be able to use passively collected gait quality data to help direct post-operative recovery using sensor-based care pathways.

Total hip arthroplasty performed by direct anterior approach - Does experience influence the learning curve?

INTRODUCTION: Proficiency in the direct anterior approach (DAA) as with many surgical techniques is considered to be challenging. Added to this is the controversy of the benefits of DAA compared to other total hip arthroplasty (THA) approaches. Our study aims to assess the influence of experience on learning curve and clinical results when transitioning from THA via posterior approach in a lateral position to DAA in a supine position. METHODS: A consecutive retrospective series of 525 total hip arthroplasty of one senior and six junior surgeons was retrospectively analysed from May 2013 to December 2017. Clinical results were analysed and compared between the two groups and represented as a learning curve. Mean follow up was 36.2 months ± 11.8. RESULTS: This study found a significant difference in complications between the senior and junior surgeons for operating time, infection rate, and lateral femoral cutaneous nerve (LFCN) neuropraxia. A trainee's learning curve was an average of 10 DAA procedures before matching the senior surgeon. Of note, the early complications correlated with intraoperative fractures increased with experience in both groups. Operating time for the senior equalised after 70 cases. Dislocation rate and limb length discrepancy were excellent and did not show a learning curve between the two groups. CONCLUSION: DAA is a safe approach to implant a THA. There is a learning curve and initial supervision is recommended for both seniors and trainees. LEVEL OF EVIDENCE: Retrospective, consecutive case series; level IV.

Transitioning the total hip arthroplasty technique from posterior approach in lateral position to direct anterior approach in supine position-risk factors for acetabular malpositioning and the learning curve.

PURPOSE: Cup positioning is important for optimum hip stability, avoiding component impingement and decreasing both bearing surface wear and revision rate. Transitioning from posterior approach in a lateral position to direct anterior approach (DAA) in a supine presents unique challenges for surgeons. The aim of this study was to examine the learning curve when using standard instrumentation that was not specific to DAA. METHODS: A consecutive retrospective series of 537 total hip arthroplasty by DAA from May 2013 to December 2017. Cup positioning was analysed on radiographs and classified whether inside or outside two safe zones (inclination 30-50° and anteversion 10-30°). The demographic data (age, BMI, gender, neck shaft angle (NSA)), surgeon's dominant side and experience were assessed as risk factors. RESULTS: Eighty per cent of cups (n = 426) were in the combined safe zones. Eighty-eight per cent (n = 470) were in appropriate anteversion and 87% (n = 463) abduction. Two factors that were significant were identified: Cups of left hips operated by right-handed surgeons were more anteverted (OR = 4.06) and more vertical (OR = 2.23); females had a higher anteversion of the cup (OR = 2.42). Obesity, age and NSA were not risk factors for cup malposition. There was a spike of cups too horizontal at the beginning of the experience (OR = 3.86), and no learning curve was observed in the other orientations. CONCLUSION: With our DAA technique using standard instrumentation, there were no risk factors linked to the patient identified for cup malposition. DAA-specific instrumentation is not required to achieve optimum positioning of the cup. Surgeon has to be aware of an excess of abduction at the beginning of his experience and an excess of anteversion and adduction when performing THA on the opposite side of his dominant hand.