Minimum 5-Year Outcomes of a Multicenter, Prospective, Randomized Control Trial Assessing Clinical and Radiological Outcomes of Patient-Specific Instrumentation in Total Knee Arthroplasty.

BACKGROUND: Patient-specific instrumentation (PSI) was developed to produce more accurate alignment of components and consequently improve clinical outcomes when used in total knee arthroplasty. We compare radiological accuracy and clinical outcomes at a minimum of 5-year follow-up between patients randomized to undergo total knee arthroplasty performed using PSI or traditional cutting block techniques. METHODS: This multicenter, randomized control trial included patients blinded to the technique 1used. Outcome measures were coronal alignment measured radiologically, Euroqol-5D, Oxford knee score, and International Knee Society Score measured at 1- and 5-year follow-up. RESULTS: At a minimum 5-year follow-up, there were 38 knees in the PSI group and 39 in the conventional instrumentation group for analysis. Baseline demographics and clinical outcome scores were matched between groups. Overall, there was no significant difference in the coronal femoral angle (P = .59), coronal tibial angle (P = .37), tibiofemoral angle (P = .99), sagittal femoral angle (P = .34), or the posterior tibia slope (P = .12) between knees implanted using PSI and those implanted with traditional cutting blocks. On the measurement of coronal alignment, intraobserver reliability tests demonstrated substantial agreement (k = 0.64). Clinical outcomes at both 1-year and 5-year follow-up demonstrated statistically significant and clinically relevant improvement in scores from baseline in both groups, but no difference could be detected between the Euroqol-5D (P = .78), Oxford knee score (P = .24), or International Knee Society Score (P = .86) between the 2 groups. CONCLUSION: This study has shown no additional benefit to PSI in terms of improved alignment or functional outcomes at minimum 5-year follow-up over traditional techniques.

Preventing ceramic liner fracture after Delta ceramic-on-ceramic total hip arthroplasty.

BACKGROUND: The results of total hip arthroplasty (THA) with use of Delta ceramic articulation were successful at medium term follow-up. The use of this newest ceramic has markedly reduced the incidence of ceramic head fractures, but not the incidence of ceramic liner fractures. We tested a hypothesis that the ceramic fractures are prevented by use of a metal shell with 18° inner taper angle and a stem design with a reduced neck geometry. METHODS: We conducted a prospective multicenter study of cementless THA with use of 32/36-mm Delta ceramic bearing, Exceed ABT metal shell and Taperloc stem. We evaluated ceramic fracture, noise, clinical results, radiological changes and survival rate at a minimum of 5-year follow-up. RESULTS: From April 2010 to February 2012, 246 patients (274 THAs) were enrolled. Among them, 224 patients (130 men and 94 women, 250 hips) were followed-up for 5-8 years (mean 6.0 years). Ceramic malseating or fracture did not occur in any patient. Eight patients (8 hips, 3.2%) reported noise. Mean Harris hip score was 84 points at the latest follow-up. All acetabular and femoral components had bone-ingrown stability. Two hips were revised due to recurrent dislocation and periprosthetic fracture. The survival rate was 99.6% at 8 years postoperatively. CONCLUSION: Ceramic fractures can be prevented by a use of (1) 32/36-mm Delta ceramic bearing, (2) metal shell with 18° taper angle, and (2) stem with a reduced neck geometry. However, noise remains a concern of the Delta ceramic bearing. LEVEL OF EVIDENCE: Therapeutic level II.

Accuracy of the newly developed Zimmer Biomet Root Aiming guide in tibial tunnel creation compared with that of conventional guides.

Background/objective: Accurate tibial tunnel creation is crucial for successful transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs). This study aimed to evaluate the accuracy of the newly developed Zimmer Biomet Root Aiming (ZeBRA) guide for transtibial pullout repair of MMPRTs. Methods: This study included 50 patients who underwent transtibial pullout repair using the Unicorn Meniscal Root (UMR) (n = 25) and ZeBRA (n = 25) guides. The expected anatomic centre (AC) and tibial tunnel centre (TC) were assessed using three-dimensional postoperative computed tomography (CT) images. The expected AC was defined as the centre of the circle tangent to the triangular footprint of the MM posterior root. The expected AC and TC on the tibial surface were assessed using the percentage-based posterolateral location on the tibial surface. The absolute distance between the AC and TC (mm) was evaluated. Results: The mean AC location was 76.1% ± 3.1% posterior and 40.8% ± 2.1% lateral, whereas the mean TC location was 76.7% ± 5.3% posterior and 37.2% ± 3.6% lateral using the UMR guide and 75.8% ± 3.1% posterior and 36.5% ± 2.4% lateral using the ZeBRA guide. No significant difference was observed in the absolute distance between the UMR and ZeBRA guides (3.9 ± 1.4 and 3.8 ± 1.3 mm, respectively; p = 0.617). Conclusions: The newly developed ZeBRA guide allows accurate tibial tunnel creation, and its accuracy is comparable to that of the conventional UMR guide. Tibial tunnels were created at optimal positions using both guides, and the choice of the guide would depend on the surgeon's preference.

Biomet stock temporomandibular joint prosthesis: Long-term outcomes of the use of titanium condyles secured with four or five condylar fixation screws.

PURPOSE: The aim of this study was to determine the long-term outcomes following TMJ replacement using the stock Zimmer-Biomet TMJ device. In particular, investigated whether the titanium condylar implant and number of screws used to fixate it to the mandibular ramus had any impact on outcomes. METHODS: Subjects who underwent surgical implantation of a stock Zimmer-Biomet TMJ prosthesis were identified for this retrospective study. All patients received a titanium condylar component secured with four or five screws and ultra-high molecular weight polyethylene (UHMWPE) fossa with no metal reinforcement. Pre- and postoperative pain scores (VAS) and maximum interincisal opening (MIO) data were collected. Additional data included patient demographics, as well as operative, postoperative and follow-up details. Data were analysed with IBM SPSS 2.0 through the use of paired t-tests, and ANOVA and ANCOVA analysis. RESULTS: 190 subjects were identified. Following exclusions, the remaining study population (n = 60) consisted of 58 females and two males with a mean age of 53.5 years at time of surgery. Preoperative VAS and MIO values were 6.08 (SD = 2.24) and 31.88 mm (SD = 7.38 mm), respectively. 90% of the cohort required four screws to fix the prosthetic condylar component in place. After a median follow up of 5.2 years (95% CI: 4.73-5.62 years), with a range of 2-9 years, the VAS was 0.91 (SD = 1.89; p < 0.001) and the MIO was 34.8 mm (SD = X; p = 0.015). Only one device failed over the 9-year study period. CONCLUSION: The results of this study demonstrate good VAS and MIO outcomes following the implantation of a stock Zimmer-Biomet TMJ device. Additionally, good long-term outcomes were obtained with a titanium condylar component, fixed to the mandibular ramus with only four or five screws, and a UHMWPE fossa with no metal reinforcement.