Kinematically aligned total knee arthroplasty (KATKA) was developed to more anatomically align the knee prosthesis to restore the native alignment of the knee and promote physiological kinematics. Even though there are concerns with implant survival, and follow-up at 10 years or more after KATKA has not been reported, there is a negligible incidence of failure of a tibial component at 2 to 9 years. Early clinical results with this technique are encouraging and demonstrate better functional outcomes compared with mechanically aligned TKA (MATKA). The purpose of this study is to perform a systematic review and meta-analysis of the literature to determine whether there are any clinical differences between KATKA and MATKA. The authors conducted a systematic review of the English literature. Five randomized controlled trials (RCTs) which compared clinical outcomes of KATKA and MATKA were finally included. Four RCTs used patient-specific instrument, and one RCT used navigation. Data were extracted and meta-analysis was conducted. KATKA patients had better outcomes: Mean difference between KATKA and MATKA and p-value are presented in brackets after each variable: the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (–12.5; p < 0.0001), Oxford Knee Score (OKS) (2.3; p = 0.030), combined Knee Society Score (C-KSS) (13.1; p < 0.0001), Knee Function Score (KFS) (6.4; p = 0.0070), and postoperative range of motion (ROM) (4.1°; p = 0.0010). There was no significant difference concerning the complication rates which needed reoperations or revision surgery (odds ratio, 1.01; p = 0.99). KATKA components had a more femoral valgus (–1.8°; p < 0.0001), more tibial varus (1.2°; p = 0.0001), and more tibial slope (1.2°; p = 0.0001), all being statistically significantly different. Better clinical outcomes were obtained in KATKA and component placement in KATKA is significantly different from that in MATKA. There was no increase of patients with poor clinical results due to implant position especially for varus placement of tibial component. This systematic review of five RCTs suggests that KATKA is of potential alternative method to MATKA since the risk of revision for tibial loosening is negligible compared with MATKA for the same follow-up period.

Background: Distal radius fracture (DRF) is very common worldwide. In particular, aging countries have numerous patients with DRF, resulting in an urgent need for active preventive measures. As few epidemiological studies have investigated DRF in Japan, we aimed to identify the epidemiological characteristics of patients of all ages with DRF in Japan. Methods: This descriptive epidemiologic study analyzed data obtained from clinical information of patients diagnosed with DRF from January 1, 2011, to December 31, 2020, at a prefectural hospital in Hokkaido, Japan. We calculated the crude and age-adjusted annual incidences of DRF and described the age-specific incidence, injury characteristics (injury location and cause, seasonal differences, and fracture classification), and 1- and 5-year mortality rates. Results: A total of 258 patients with DRF were identified, of which 190 (73.6%) were female and the mean age (standard deviation) was 67.0 (21.5) years. The crude annual incidence of DRF ranged from 158.0 to 272.6 per 100,000 population/year, and the age-adjusted incidence among female patients demonstrated a significant decreasing trend during 2011–2020 (Poisson regression analysis; p = 0.043). The age-specific incidence differed by sex, with peaks at 10–14 years for males and 75–79 years for females. The most common cause of injury was a simple fall in patients > 15 year of age and sports injuries in patients ≤ 15 years of age. DRFs were most frequently sustained outdoors and were more common in the winter season. In patients > 15 years of age, the proportions of AO/OTA fracture types A, B, and C were 78.7% (184/234), 1.7% (4/234), and 19.6% (46/234), respectively, and 29.1% (68/234) of patients received surgical treatment for DRF. The 1- and 5-year mortality rates were 2.8% and 11.9%, respectively. Conclusions: Our findings were mostly consistent with previous global studies. Although the crude annual incidence of DRF was relatively high because of recent population aging, the age-adjusted annual incidence among female patients showed a significant decreasing trend during this decade.

Knee joint distraction (KJD) is a new application of an established technique to regenerate native cartilage using an external fixator. The purpose of this study is to perform a systematic review and meta-analysis of the literature to determine whether KJD is beneficial for knee osteoarthritis and how results compare with established treatments. Studies assessing the outcomes of KJD were retrieved, with three studies (one cohort and two randomized controlled trials), 62 knees, meeting the inclusion criteria. The primary outcome was functional outcome, assessed using a validated outcome score, at 1 year. Secondary outcomes included pain scores, structural assessment of the joint, and adverse events. KJD is associated with improvements in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) from baseline to 1 year as well as reductions in pain scores and improvements in structural parameters assessed radiographically and by magnetic resonance imaging. KJD is not associated with decreased knee flexion, but is associated with a high risk of pin site infection. In patients aged 65 years or under at 1 year, no differences in WOMAC or pain scores was detected between patients managed with KJD compared with high tibial osteotomy or total knee arthroplasty. KJD may represent a potential treatment for knee arthritis, though further trials with longer term follow-up are required to establish its efficacy compared with contemporary treatments. This is a Level I (systematic review and meta-analysis) study. This is a systematic review so ethical approval was waived. ^* Thomas W. Hamilton is the senior co-author of the study.

Kinematically aligned total knee arthroplasty (KATKA) was developed to improve the anatomical alignment of knee prostheses, assisting in restoring the native alignment of the knee and promoting physiological kinematics. Early clinical results were encouraging, showing better functional outcomes than with mechanically aligned total knee arthroplasty (MATKA). However, there have been concerns about implant survival, and follow-up at 10 years or more has not been reported. In addition, randomized controlled trials (RCTs) comparing KATKA with MATKA have reported inconsistent results. The current meta-analysis of RCTs with a minimum of 2 years of follow-up investigated the clinical and radiological differences between KATKA and MATKA. A systematic review of the English language literature resulted in the inclusion of four RCTs. The meta-analysis found no significant difference in any of the following parameters: postoperative range of motion for flexion (mean difference for KATKA − MATKA [MD], 1.7 degrees; 95% confidence interval [CI], −1.4 to 4.8 degrees; p = 0.29) and extension (MD, 0.10 degrees; 95% CI, −0.99 to 1.2 degrees; p = 0.86); Oxford Knee Score (MD, 0.10 points; 95% CI, −1.5 to 1.7 points; p = 0.90); Knee Society Score (MD, 1.6 points; 95% CI, −2.8 to 6.0 points; p = 0.49); and Knee Function Score (MD, 1.4 points; 95% CI, −4.9 to 7.8 points; p = 0.66). In addition, there was no significant difference between KATKA and MATKA in the rate of complications requiring reoperation or revision surgery (odds ratio, 1.01; 95% CI, 0.25–4.09; p = 0.99) or in the length of hospital stay (MD, 1.0 days; 95% CI, −0.2 to 2.2 days; p = 0.092). KATKA did not increase the number of patients with poor clinical results due to implant position, particularly for varus placement of the tibial component. In this meta-analysis based on four RCTs with a minimum of 2 years of follow-up, KATKA were only relevant to cruciate retaining TKA and could not be extrapolated to posterior stabilized TKA. Patient-reported outcome measures with KATKA were not superior to those with MATKA.

Several investigators have developed anterior cruciate ligament reconstructions (ACLR) with remnant tissue preservation (RTP) and have reported better clinical outcomes. However, the effects of RTP remain controversial. To date, no reports have compared both clinical and radiological outcomes of anatomic double-bundle ACLR using the hamstring tendon and outside-in technique with/without RTP. This article evaluates the effectiveness of RTP in ACLR on knee stability and graft maturation. In total, 75 patients with unilateral ACL injury who had undergone anatomic double-bundle ACLR using autografted hamstring tendon either with RTP (Group P, n = 43) or without (Group N, n = 32) were enrolled. Clinical scores, pre- and postoperative side-to-side differences (SSDs) obtained using Telos, radiological evaluations of the grafted tendon using the signal/noise quotient (SNQ) measured using magnetic resonance imaging, and arthroscopic evaluations of the grafted tendon were retrospectively compared between the groups. Postoperative SSDs were smaller in the Group P (0.78 ± 1.90 mm) than in the Group N (1.29 ± 2.18 mm); however, this difference was not significant. Comparing two subgroups of the Group P, the SSD was significantly smaller in those with sufficient remnant coverage (−0.56 ± 1.38 mm) than in those without (1.48 ± 1.77 mm) (p = 0.019), as well as in the Group N patients (p = 0.019). The degree of synovial coverage of the anteromedial (p = 0.0064) and posterolateral (p = 0.032) bundle grafted tendon at the time of second-look arthroscopy was significantly better in the Group P than in the Group N. SNQ values of ACL grafted tendon at proximal (p = 0.049), middle, and distal (p = 0.039) one-third in Group P were better than those in Group N. RTP may enhance synovial coverage and maturation of the grafted tendon. Sufficient remnant tissue coverage may contribute to better knee stability. This is a Level III, retrospective comparative study. This study was performed at Gunma Sports Medicine Research Center, Zenshukai Hospital, Maebashi, Japan. T.T. designed the study and acquired, analyzed, and interpreted data. M.K., K.H., T.O., and K.T. participated in study conception and design and revision of the data and manuscript. All authors read and approved the final manuscript. The Institutional Review Board of the ethics committee of our institution approved this retrospective comparative study. Approval number was 170404. This research involved a retrospective comparative study of electronic medical records and videos collected at the time of ACL reconstruction surgery and second look arthroscopy. Therefore, the ethical committee of our institution waived the requirement for formal written informed consent.