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Purpose: In contrast to total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) is a true resurfacing procedure, as none of the ligaments are replaced or released, and the pre-arthritic leg alignment is the major goal. As such, the alignment of the tibial component plays a crucial role in postoperative knee function and long-term survival. Pinless navigation has shown reliable results in total knee arthroplasty. To the best of our knowledge, the use of pinless navigation has not been investigated for UKA. Therefore, the present study investigated whether implantation of the tibial component in 3° varus, which is closer to the anatomical axis, is feasible with a pinless optical navigation system. Methods: 60 patients with the diagnosis of an unicompartmental arthritis, were eligible for UKA and treated with implantation in 3° varus alignment of the tibial component. Two groups were established. In the treatment group the tibial component was aligned using a pinless navigation technique. In the control group, a conventional extramedullary alignment guide was used. A clinical and radiographic follow up took place within 1 year of operation. Results: 57 Patients were eligible for analysis. No clinical incidents were noted in the follow up period. The desired target value, the position of the tibial component, was accurately achieved with an average of 3° medial inclination using the pinless navigation as well as using the conventional technique. Mean incision to suture time was negligible between the two techniques. The mean suture time was 43.2 min with pinless navigation and 42.7 min with the conventional technique. Conclusions: With pinless navigation in UKA, a method was presented that made it possible to achieve sled prosthesis alignment at the level of a high-volume surgeon. These results were achieved with an irrelevant increase of surgical time and without placement of pins. [ABSTRACT FROM AUTHOR]

High complication rates in total wrist arthroplasty (TWA) still lead to controversy in the medical literature, and novel methods for complication reduction are warranted. In the present retrospective cohort study, we compare the outcomes of the proximal row carpectomy (PRC) method including total scaphoidectomy (n = 22) to the manufacturer's conventional carpal resection (CCR) technique, which retains the distal pole of the scaphoid (n = 25), for ReMotion prosthesis implantation in non-rheumatoid patients. Mean follow-up was 65.8 ± 19.8 and 80.0 ± 28.7 months, respectively. Pre- and postoperative clinical assessment included wrist flexion-extension and radial-ulnar deviation; Disability of Arm, Shoulder, and Hand scores; and pain via visual analogue scale. At final follow-up, grip strength and satisfaction were evaluated. All complications, re-operations, and revision surgeries were noted. Clinical complications were significantly lower in the PRC group (p = 0.010). Radial impaction was detected as the most frequent complication in the CCR group (n = 10), while no PRC patients suffered from this complication (p = 0.0008). Clinical assessment, grip strength measurements, and the log rank test evaluating the re-operation as well as revision function showed no significant difference. All functional parameters significantly improved compared to preoperative values in both cohorts. In conclusion, we strongly recommend PRC for ReMotion prosthesis implantation. [ABSTRACT FROM AUTHOR]

There have been remarkable advances in knee replacement surgery over the last few decades. One of the concerns continues to be the accuracy in achieving the desired alignment. Patient-specific instrumentation (PSI) was developed to increase component placement accuracy, but the available evidence is not conclusive. Our study aimed to determine a PSI system's three-dimensional accuracy on 3D virtual models obtained by post-operative computed tomography. We compared the angular placement values of 35 total knee arthroplasties (TKAs) operated within a year obtained with the planned ones, and we analyzed the possible relationships between alignment and patient-reported outcomes. The mean (SD) discrepancies measured by two experienced engineers to the planned values observed were 1.64° (1.3°) for the hip–knee–ankle angle, 1.45° (1.06°) for the supplementary angle of the femoral lateral distal angle, 1.44° (0.97°) for the proximal medial tibial angle, 2.28° (1.78°) for tibial slope, 0.64° (1.09°) for femoral sagittal flexion, and 1.42° (1.06°) for femoral rotation. Neither variables related to post-operative alignment nor the proportion of change between pre-and post-operative alignment influenced the patient-reported outcomes. The evaluated PSI system's three-dimensional alignment analysis showed a statistically significant difference between the angular values planned and those obtained. However, we did not find a relevant effect size, and this slight discrepancy did not impact the clinical outcome. [ABSTRACT FROM AUTHOR]

Because of preservation of proximal femoral bone stock and minimized soft tissue trauma, short-stem implants are becoming increasingly important in total hip arthroplasty (THA). The postulated advantage regarding the functional outcome has not been verified. We hypothesized an increased abductor muscle strength by the use of a short-stem design. Seventy consecutive patients of a randomized clinical trial were included. Of these, 67 patients met the inclusion criteria after 12 months. Thirty-five patients received a standard straight stem and 32 patients a short-stem femoral component. All surgeries were performed by a modified direct lateral approach. Isometric muscle strength of the hip abductors was evaluated preoperatively 3 and 12 months after surgery. Harris hip score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were evaluated. After three months, there were no differences between the two groups; the abductor force was comparable to the preoperative initial values. After 12 months, a significant increase in muscle strength for the short stem patient group compared to preoperative baseline values was measured (straight-stem THA, 0.09 Nm/kg ± 0.4, p = 0.32; short-stem THA, 0.2 Nm/kg ± 0.3, p = 0.004). Comparison of the 12-month postoperative total HHS and WOMAC revealed no significant differences between both groups. A significant increase in hip abductor muscle strength 12 months after short-stem THA compared to conventional-stem THA was observed. [ABSTRACT FROM AUTHOR]

The German Arthroplasty registry (EPRD) has shown that different prosthesis systems have different rates of secondary patellar resurfacing: four years after implantation, the posterior-stabilized (PS) Vega prosthesis has a 3.2% risk of secondary patellar resurfacing compared to the cruciate-retaining (CR) Columbus prosthesis at 1.0% (both Aesculap AG, Tuttlingen, Germany). We hypothesized that PS implants have increased retropatellar pressure and a decreased retropatellar contact area compared to a CR design, which may lead to an increased likelihood of secondary patellar resurfacing. Eight fresh frozen specimens (cohort 1) were tested with an established knee rig. In addition, a possible influence of the registry-based patient collective (cohort 2) was investigated. No significant differences were found in patient data–cohort 2-(sex, age). A generally lower number of PS system cases is noteworthy. No significant increased patella pressure could be detected with the PS design, but a lower contact area was observed (cohort 1). Lower quadriceps force (100°–130° flexion), increased anterior movement of the tibia (rollback), greater external tilt of the patella, and increasing facet pressure in the Vega PS design indicate a multifactorial cause for a higher rate of secondary resurfacing which was found in the EPRD patient cohort and might be related to the PS' principle function. [ABSTRACT FROM AUTHOR]

Periprosthetic joint infection (PJI) is one of the most common complications in total hip arthroplasty (THA). The influence of bearing material on the risk of PJI remains unclear to date. This registry-based matched study investigates the role of bearing partners in primary cementless THA. Primary cementless THAs recorded in the German Arthroplasty Registry since 2012 with either a ceramic-on-ceramic (CoC) or ceramic-on-polyethylene (CoP) bearings were included in the analysis. Using propensity score matching (PSM) for age, sex, obesity, diabetes mellitus, Elixhauser comorbidity index, year of surgery and head size, we compared the risk for revision for PJI for CoC and CoP. Within the 115,538 THAs (87.1% CoP; 12.9% CoC), 977 revisions were performed due to PJI. There was a significantly higher risk for revision for PJI for CoP compared with CoC over the whole study period (p < 0.01) after 2:1 matching (CoP:CoC) with a hazard ratio of 1.41 (95% confidence interval (CI), 1.09 to 1.80) After 3 years, the risk for revision for PJI was 0.7% (CI 0.5–0.9%) for CoC and 0.9% (CI 0.8–1.1%) for CoP. The risk for revision for all other reasons except PJI did not significantly differ between the two groups over the whole study period (p = 0.4). Cementless THAs with CoC bearings were less likely to be revised because of infection in mid-term follow-up. In the future, registry-embedded studies focusing on long-term follow-up, including clinical data, as well as basic science studies, may give a deeper insight into the influence of the bearing partners. [ABSTRACT FROM AUTHOR]

Due to the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic, a large number of elective knee replacement procedures had to be postponed in both early and late 2020 in most western countries including Germany and the UK. It is unknown how public interest and demand for total knee arthroplasties was affected. Public interest in knee pain, knee osteoarthritis and knee arthroplasty in Germany and the UK was investigated using Google Trend Analysis. In addition, we monitored for changes in patient composition in our outpatient department. As of early March in Germany and of late March in the UK, until the lockdown measures, a 50 to 60% decrease in relative search frequency was observed in all categories investigated compared to the beginning of the year. While public interest for knee pain rapidly recovered, decreased interest for knee osteoarthritis and replacement lasted until the easing of measures. Shortly prior to and during the first lockdown mean search frequency for knee replacement was significantly decreased from 39.7% and 36.6 to 26.9% in Germany and from 47.7% and 50.9 to 23.7% in the UK (Germany: p = 0.022 prior to lockdown, p < 0.001 during lockdown; UK: p < 0.0001 prior to and during lockdown). In contrast, mean search frequencies did not differ significantly from each other for any of the investigated time frames during the second half of 2020 in both countries. Similarly, during the first lockdown, the proportion of patients presenting themselves to receive primary knee arthroplasty compared to patients that had already undergone knee replacement declined markedly from 64.7% to 46.9%. In contrast, patient composition changed only marginally during the lockdown measures in late 2020 in both Germany and the UK. We observed a high level of public interest in knee arthroplasty despite the ongoing pandemic. The absence of a lasting decline in interest in primary knee arthroplasty suggests that sufficient symptom reduction cannot be achieved without surgical care for a substantial number of patients. [ABSTRACT FROM AUTHOR]

Background: A major disadvantage of current spacers for two-stage revision total knee arthroplasty (R-TKA) is the risk of (sub-) luxation during mobilization in the prosthesis-free interval, limiting their clinical success with detrimental consequences for the patient. The present study introduces a novel inverse spacer, which prevents major complications, such as spacer (sub-) luxations and/or fractures of spacer or bone. Methods: The hand-made inverse spacer consisted of convex tibial and concave femoral components of polymethylmethacrylate bone cement and was intra-operatively molded under maximum longitudinal tension in 5° flexion and 5° valgus position. Both components were equipped with a stem for rotational stability. This spacer was implanted during an R-TKA in 110 knees with diagnosed or suspected periprosthetic infection. Postoperative therapy included a straight leg brace and physiotherapist-guided, crutch-supported mobilization with full sole contact. X-rays were taken before and after prosthesis removal and re-implantation. Results: None of the patients experienced (sub-) luxations/fractures of the spacer, periprosthetic fractures, or soft tissue compromise requiring reoperation. All patients were successfully re-implanted after a prosthesis-free interval of 8 weeks, except for three patients requiring an early exchange of the spacer due to persisting infection. In these cases, the prosthetic-free interval was prolonged for one week. Conclusion: The inverse spacer in conjunction with our routine procedure is a safe and cost-effective alternative to other articulating or static spacers, and allows crutch-supported sole contact mobilization without major post-operative complications. Maximum longitudinal intra-operative tension in 5° flexion and 5° valgus position appears crucial for the success of surgery. [ABSTRACT FROM AUTHOR]

Introduction: Total ankle arthroplasty (TAA) is becoming a more frequent treatment option for end-stage ankle osteoarthritis (OA) as outcomes measures are improving. However, there is concern that malalignment of TAA can result in premature failure of the implant. One of the malalignment issues is the talar sagittal malposition. However, a consensus on the significance of the sagittal translation of the talus in TAA is yet to be established. The aim of this study was, therefore, to clarify whether talus OA subluxation is normalized after the implantation of a mobile TAA. Methods: Forty-nine consecutive patients with symptomatic end-stage ankle OA underwent 50 cementless three-component mobile-bearing VANTAGE TAA with 21 right ankles (42%) and 29 left ankles (58%). Clinical and radiographic outcomes were assessed: Clinical variables: American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score (0–100), visual analogue scale (VAS, 0–10), and ankle range of motion (ROM). Radiological variables: medial distal tibial articular angle (mDTAA), anterior distal tibial articular angle (aDTAA) and lateral talar station (LTS). Results: The clinical results showed the mean improvement in AOFAS hindfoot score from 42.12 ± SE 2.42 (Range: 9–72) preoperatively, to 96.02 ± SE 0.82 (Range: 78–100) at a mean follow-up of 12 months, with a highly statistically significant difference (p < 0.00001). Pain score (VAS) was 6.70 ± SE 0.28 (Range 0–10) preoperatively, and 0.26 ± SE 0.12 (Range: 0–3) at 12-month follow-up, with a highly statistically significant difference (p < 0.00001). ROM measurements preoperatively showed a mean of 22.55° ± SE 1.51° (Range: 0–50°), which showed a statistically significant improvement (p < 0.0001) to 45.43° ± SE 1.56° (Range: 25–60°) 12 months postoperatively. The radiological analyses revealed the following results: On the coronal view, the mDTAA preoperatively was 88.61 ± SE 0.70 (Range: 78.15–101.10), which improved to 89.46 ± SE 0.40 (Range: 81.95–95.80) at 12 months (not statistically significant—p = 0.94). On the sagittal view, the preoperative values of the aDTAA showed 82.66 ± SE 0.84 (Range: 70.35–107.47), which improved to 88.98 ± SE 0.47 (Range: 82.83–96.32) at 12 months postoperatively, with a highly statistically significant difference between preoperative and 12-months values (p < 0.00001). The mean LTS values for all patients were 3.95 mm ± SE 0.78 (Range: −11.52 to 13.89) preoperatively and 1.14 mm ± SE 0.63 (Range: −10.76 to 11.75) at 12 months, with a statistically significant difference between preoperative and 12-month follow-up (p = 0.01). The review of the radiological TAA osteointegration at 12 months showed no cases of loosening of the implanted TAAs. Two cases (4%) showed a radiolucency and one case (2%) a cyst on the tibial component; no cases had a change on the talar component. No TAA complication/revision surgeries were documented. Conclusion: In the present study, the lateral talar station of anteriorly subluxated ankles showed a significant improvement, i.e., physiological centralization of the talus, in the postoperative period when a mobile-bearing TAA was performed. The anterior/posterior congruency between the talar component and the mobile polyethylene insert of the mobile-bearing VANTAGE TAA allows the sagittal translation of the talus relative to the flat tibial component, reducing the prosthesis strain and failure. [ABSTRACT FROM AUTHOR]

Surgical risk factors for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) are the subjects of ongoing research. It is unclear if there are specific locations of the surgical area that might act as a pathogen source. Due to the fact that bacterial replication occurs preferably under humid conditions, it was our aim to investigate if irrigation fluid reservoirs on the surgical covers are subject to bacterial colonization. We prospectively observed 40 patients with scheduled aseptic 1-stage TKA revision. At time intervals of 30 min, irrigation samples were tested for microbiological colonization. Additionally, the suction tip was investigated at the end of surgery. Overall, a bacterial detection rate of 25% was found (57/232 samples). Analysis for any positive microbial detection revealed pathogen findings of irrigation fluid in 41.7% of samples after 30 min with a constant increase up to 77.8% after 90 min. Twenty-three percent of suction tips showed bacterial colonization. Coagulase-negative staphylococci, accounting for the majority of PJI, were the predominant pathogens. After an average follow-up of 17 months, no PJI was confirmed. Despite the substantial bacterial load of irrigation fluid, PJI rates were not elevated. Nevertheless, we recommend that irrigation fluid reservoirs should be prevented and not withdrawn by suction. [ABSTRACT FROM AUTHOR]