Identifying Reasons for Failed Same-Day Discharge Following Primary Total Hip Arthroplasty

© 2018 Elsevier Inc. Background: As total hip arthroplasty (THA) gains popularity in ambulatory surgery centers, it is important to understand the causes of failed same-day discharge (SDD). The purpose of this study is to (1) identify reasons for an overnight stay among patients selected as candidates for SDD following THA and (2) determine what pre-operative factors are more common among patients who fail SDD. Methods: This is a prospective cohort study of patients undergoing THA who were identified as candidates for SDD (\u3c75 \u3eyears, ambulate without walker, American Society of Anesthesiologists score 1-3, body mass index /m2, and agreed to SDD pre-operatively). The primary outcome was the reason for not discharging home on the same day of surgery. Secondary outcomes included the proportion of patients who failed SDD and any pre-operative patient characteristics that could be linked to failed SDD. Results: Seventy-eight of 106 (74%) patients pre-selected for SDD were successfully discharged per protocol. Of the 28 (26%) patients who failed SDD, the most common reasons for failure were patient preference (12), dizziness or hypotension (8), failure to clear physical therapy (5), urinary retention (2), and pain management (1). There was a higher percentage of patients in the failed SDD group who reported multiple allergies (P = .02), anxiety/depression (P = .24), obstructive sleep apnea (P = .38), and rheumatoid arthritis (P = .02). Conclusion: SDD is a viable option for surgeons interested in rapid recovery THA. In a pool of patients selected for SDD, the main cause of SDD failure was a change in patient preference post-operatively, despite having agreed to SDD pre-operatively and meeting all discharge criteria

Impaction Force Influences Taper-Trunnion Stability in Total Hip Arthroplasty

© 2018 Elsevier Inc. Background: This study investigated the influence of femoral head impaction force, number of head strikes, the energy sequence of head strikes, and head offset on the strength of the taper-trunnion junction. Methods: Thirty titanium-alloy trunnions were mated with 36-mm zero-offset cobalt-chromium femoral heads of corresponding taper angle. A drop tower impacted the head with 2.5J or 8.25J, resulting in 6 kN or 14 kN impaction force, respectively, in a single strike or combinations of 6 kN + 14 kN or 14 kN + 14 kN. In addition, ten 36-mm heads with −5 and +5 offset were impacted with sequential 14 kN + 14 kN strikes. Heads were subsequently disassembled using a screw-driven mechanical testing frame, and peak distraction force was recorded. Results: Femoral head pull-off force was 45% the strike force, and heads struck with a single 14 kN impact showed a pull-off force twice that of the 6 kN group. Two head strikes with the same force did not improve pull-off force for either 6 kN (P =.90) or 14 kN (P =.90). If the forces of the 2 impactions varied, but either impact measured 14 kN, a 51% higher pull-off force was found compared to impactions of either 6 kN or 6 kN + 6 kN. Femoral head offset did not significantly change the pull-off force among −5, 0, and +5 heads (P =.37). Conclusion: Femoral head impaction force influenced femoral head trunnion-taper stability, whereas offset did not affect pull-off force. Multiple head strikes did not add additional stability, as long as a single strike achieved 14 kN force at the mallet-head impactor interface. Insufficient impaction force may lead to inadequate engagement of the trunnion-taper junction

The Bimetric cementless total hip replacement: 7–18 year follow-up assessing the influence of acetabular design on survivorship

The purpose of this study was to evaluate the mid- to long-term survivorship of Bimetric cementless total hip replacement and assess how it is affected by the acetabular design. This was a retrospective analysis of 127 Bimetric cementless total hip replacements in 110 patients with a follow-up of 7–18 years. A single design stem and three different cementless metal-backed acetabular designs were used. Patients were assessed clinically using the Harris hip score and radiologically by independent review of current hip radiographs. There was only one case of aseptic loosening of the femoral stem. The earliest acetabular design showed a high failure rate whilst the latter two designs showed a 96% survivorship at a mean of 9.5 years. We conclude that a combination of the bimetric stem with either of the latter acetabular cup designs has a good mid- to long-term performance