Improved outcomes in patients with positive metal sensitivity following revision total knee arthroplasty.

BACKGROUND: Metal sensitivity as a cause for painful joint replacement has become increasingly prevalent; however, there is a lack of reported clinical outcome data from total knee arthroplasty patients with metal allergies. The purpose of this study was to determine whether patients presenting with a painful total knee arthroplasty with a positive metal sensitivity have improved outcomes following revision to a hypoallergenic implant. METHODS: A retrospective review was conducted for patients that underwent a revision total knee arthroplasty after metal sensitivity testing over a 3-year period from January 1, 2015, to December 31, 2017. Based on the results of sensitivity testing, patients underwent revision total knee arthroplasty to a hypoallergenic component or a standard component. Following revision, patients returned to the clinic at an interval of 6 weeks, 5 months, and 12 months for functional, pain, and satisfaction assessment. Outcomes were compared within and between sensitivity groups. RESULTS: Of the included patients, 78.3% (39/46) were positive for metal sensitivity. The most common metal sensitivity was to nickel (79.5%, 32/39). Both non-reactive and reactive patients significantly improved in range of motion after revision arthroplasty. The reactive group saw a 37.8% decrease in pain at 6 weeks post-revision (p < 0.001) Whereas, the non-reactive group only saw a moderate, non-significant improvement in pain reduction at 6 weeks post-revision (27.0%; p = 0.29). Frequency of pain experienced did not vary significantly between groups. Maximum metal lymphocyte transformation test (LTT) sensitivity score did not correlate with pain level at the time of revision (R2 = 0.02, p = 0.38) or percent improvement after revision (R2 = 0.001, p = 0.81). Overall, all patients reported being very satisfied after revision total knee arthroplasty; there was no difference between positive and negative sensitivity groups (W = 62, p = 0.89). CONCLUSIONS: Patients presenting with a painful knee arthroplasty and positive metal LTT have improved pain scores, walking function, and range of motion following revision to a hypoallergenic component. This study also provides a treatment algorithm for patients presenting with a painful knee replacement, in order to provide effective and timely diagnosis and management.

Catastrophic failure of a dual mobility bearing in a revision total hip arthroplasty.

The following case demonstrates an example of a catastrophic failure of a dual mobility (DM) bearing used in the setting of a revision total hip arthroplasty for an acetabular component with an excessive abduction angle. Currently, in the literature, it has been demonstrated that DM bearings have decreased polyethylene wear at abduction angles up to 65°; however, this has only been shown in in vitro studies. To our knowledge, there have been no reports of in vivo DM bearings that have demonstrated these same results. In this case, a DM bearing was used in a revision surgery with a retained acetabular component that had an abduction angle of approximately 70°-75° which ultimately led to catastrophic polyethylene failure.

Topical Tranexamic Acid Reduces Postoperative Blood Loss in Primary Total Hip and Knee Arthroplasty.

CONTEXT: The purpose of this study was to assess the effectiveness of topical pre-closure application of tranexamic acid (TXA) to reduce postoperative blood loss and blood transfusion rates in primary total hip and knee arthroplasty (THA and TKA) in a private, high-volume orthopedic specialty hospital setting. METHODS: This was a retrospective study examining 140 consecutive patients undergoing primary hip or knee arthroplasty at the sample setting by a single surgeon. The first 70 patients did not receive topical TXA (2 gm./20ml.), the final 70 did receive topical TXA. We compared the postoperative hemoglobin levels of both sample subgroups at postoperative days 1, 2, and 3. RESULTS: Overall, the postoperative hemoglobin levels were significantly higher in the TXA group on postoperative days 1, 2, and 3 (p < 0.05). When patients who underwent THA (n = 70) were investigated separately, the hemoglobin levels were significantly higher on postoperative days 1, 2, and 3 in the group that received TXA. In the TKA group (n = 70), there was not a significantly higher hemoglobin level in patients who received TXA. There were no blood transfusions in the entire study cohort. Possibly due to the more restrictive transfusion criteria employed in this study, the total estimated prospective cost savings from use of TXA was calculated at about $116 per patient. CONCLUSIONS: Based on these results from a high volume orthopedic specialty hospital, pre-closure topical TXA application may prove effective in reducing postoperative blood loss for some patients but have a relatively small impact on cost outcomes.