Consistency of Acetabular Height in Sequential Bilateral Total Hip Arthroplasty

Background: Achieving appropriate leg length after surgery remains a concern for surgeons performing total hip arthroplasty (THA). The focus of surgeons trying to equalize leg length has been primarily on positioning of the femoral implant. This study evaluates the impact of acetabular height on leg length and its impact on femoral component choices during THA. Methods: We reviewed standing pelvic radiographs of 100 patients who underwent staged bilateral THA by a single surgeon from 2016 to 2019. Leg length discrepancies and acetabular heights were determined from preoperative and postoperative radiographs. The difference between the first and second operative hips was compared at each stage of the procedures. Results were analyzed using paired t-tests. Results: There is a significant increase in mean leg length and acetabular height after both the first and second stages of the procedure. Although there was a small change in average acetabular height for each procedure, height increased or decreased by greater than 5 mm in 44 of 200 cases. Comparing left to right hips after the second surgery disclosed no statistically significant differences in acetabular height or leg length. Conclusion: Acetabular height and leg length changes with each stage of the procedure in sequential bilateral THA. In almost 25% of cases, the acetabular height changed by more than 5 mm. This has significant implications and needs to be considered during preoperative planning as well as operative decision-making. To account for these differences, a THA may require intraoperative acetabular assessment and changes in femoral positioning and sizing to achieve the optimal leg length

Intraoperative Acoustics: Auditory Cues in Hip Reconstructive Surgery

Background: Orthopaedic surgeons rely on visual and tactile cues to guide performance in the operating room (OR). However, there is very little data on how sound changes during orthopaedic procedures and how surgeons incorporate audio feedback to guide performance. This study attempts to define meaningfulchanges in sound during vital aspects of total hip arthroplasty (THA) within the spectrum of human hearing. Methods: 84 audio recordings were obtained during primary elective THA procedures during sawing of the femoral neck, reaming of the acetabulum, acetabular cup impaction, polyethylene liner impaction, femoral broaching, planning of the femoral calcar and press-fit of a porous-coated stem in 14 patients. We graphed changes in frequency intensity across the human spectrum of hearing and sampled frequencies showing differences over time for statistically meaningful changes. Results: Sawing of the femoral neck, polyethylene impaction, and stem insertion showed significant temporal increases in overall sound intensity. Calcar planing showed a significant decrease in sound intensity. Moreover, spectrographic analysis showed that, for each of the critical tasks in THA, there werecharacteristic frequencies that showed maximal changes in loudness. These changes were above the 1 dB change in intensity required for detection by the human ear. Conclusion: Our results clearly demonstrate reproducible sound changes during total hip arthroplasty that are detectable by the human ear. Surgeons can incorporate sound as a valuable source of feedback while performing total hip arthroplasty to guide optimal performance in the OR. These findings can be extrapolated to other orthopaedic procedures that produce characteristic changes in sound. Moreover, it emphasizes the importance of limiting ambient noise in the OR that might make sound changes hard to distinguish. Level of evidence: I