Modern Day Bicruciate-Retaining Total Knee Arthroplasty: A Short-Term Review of 146 Knees.

BACKGROUND: Bicruciate retaining (BCR) implants were first proposed in the 1960s with the polycentric knee. Given the technical difficulty of implanting these devices, and the mixed results at the time, the BCR concept had stalled, until recently. This study seeks to provide a short-term review of the BCR implant design, describe patient-reported outcomes, and discuss key aspects to ensure successful implantation of the modern-day BCR implant design. METHODS: Between October 2014 and December 2016, the senior author performed 146 primary total knee arthroplasties using BCR implants. Arthritic knees, with minimal soft tissue damage and an intact anterior cruciate ligament, were the general indications used for this cohort. All patients implanted with the BCR device were included in this analysis. One hundred forty-six (100%) BCR knees were available for follow-up at an average of 12 months (range, 1-33 months) postoperatively. RESULTS: Ninety-one percent of respondents reported their knee always or sometime feels normal, with only 9% of respondents reporting their knee never feels normal. Our study reports 94% of patients reported neutral satisfaction or higher, with only 6% of patients reporting dissatisfaction and 1% reported being very dissatisfied. Of all 146 BCR devices implanted, there were 2 (1.4%) revisions and 1 (0.7%) reoperation, a manipulation under anesthesia. CONCLUSION: This is the largest consecutive series of BCR total knee arthroplasties using the modern-day implant design with 1-year follow-up in the United States. The results of our study show great patient-reported satisfaction, function, and short-term outcomes for patients implanted with the new BCR design.

Increasing Liner Anteversion Decreases the Interfacial Strength of Polyethylene Liners Cemented Into Titanium-Alloy Acetabular Shells.

BACKGROUND: Acetabular component positioning during revision total hip arthroplasty can be suboptimal. Cementation of an acetabular liner into a well-fixed acetabular shell can allow surgeons to correct component version and inclination without the need for extensive revision surgery and progressive pelvic bone loss. However, to date, it is unknown what degree of version can be corrected without sacrificing fixation strength of the construct. In this study, cemented liners were biomechanically evaluated at increasing degrees of liner anteversion. METHODS: Twenty-five commercially available liners were cemented into acetabular shells at 0°, 10°, 20°, 30°, and 40° of liner anteversion, relative to the acetabular shell (n = 5 per group). Components were then fixed to a materials testing frame and evaluated via an established lever-out testing protocol. Test data were collected via test frame software for calculation of yield and maximum moments during biomechanical testing. RESULTS: When liners were cemented at 20°, 30°, and 40° of liner anteversion, a significant decrease in maximum fixation moment was found when compared liners cemented at both 0° and 10° (P < .05). A significant negative correlation was noted for both yield and maximum moments and increasing liner angle (r = -0.566; P = .011 and r = -0.604; P = .006, respectively). CONCLUSION: Biomechanical data from our study suggest that a threshold of acceptable anteversion during revision total hip arthroplasty is <20°. However, further studies are warranted to continue evaluation of the potential clinical impact and long-term device performance in this setting.

Cemented femoral stem fixation through the anterior approach has fewer early complications than cementless fixation.

AIMS: To achieve the functional benefits of the direct anterior (DA) approach and the fixation benefits of cemented replacement, this study combined the two techniques posing the following questions: does the limited access of the DA approach adversely affect the cement technique?; and does such a cementing technique reduce the incidence of cementless complications? METHODS: A consecutive series of 341 patients (360 hips) receiving the DA approach between 2016 and 2018 were reviewed. There were 203 cementless stems and 157 cemented stems. Mean age was 75 years (70 to 86) in the cementless group and 76 years (52 to 94) in the cemented group, with 239 (70%) females in the whole series. Femoral complications were compared between the two groups. Mean follow-up was 1.5 years (0.1 to 4.4) for patients in the cementless group and 1.3 years (0.0 to 3.9) for patients in the cemented group. RESULTS: The cementless group had a higher rate of femoral complications (8 vs 0; p = 0.011). There were two loose stems and six fractures, all requiring revision. Fractures occurred a mean 14.5 days (2 to 31) postoperatively and loosening at 189 days and 422 days postoperatively. Femoral cementing can be done using the DA approach safely and reduces the number of complications compared with a contemporary cementless series. CONCLUSION: A higher rate of early fractures and loosening occurred with cementless stems. This was not observed in our cemented stem cohort and cementing was safely accomplished through the DA approach. The modern femoral cementing process with the DA approach does not add to surgical complexity or time, has fewer early complications, and is a safer option for older patients compared to cementless femoral arthroplasties. Cite this article: Bone Joint J 2021;103-B(7 Supple B):33-37.