Collagen Meniscal Scaffold Implantation Can Provide Meniscal Regeneration in Asian Patients with Partial Meniscal Defects: A Prospective Randomized Controlled Study with Three-Dimensional Volume Analysis of the Meniscus.

Background: To date, the efficiency of collagen meniscal scaffold implantation in Asian patients with partial meniscal defects has not been evaluated. In addition, no study has quantitatively analyzed meniscal regeneration using three-dimensional (3D) volume analysis after collagen scaffold implantation. We aimed to compare meniscal regeneration using 3D volume analysis between Asian patients undergoing collagen-based meniscal scaffold implantation after partial meniscectomy and those undergoing only partial meniscectomy. Methods: Nineteen patients who underwent collagen-based meniscal scaffold implantation and 14 who underwent partial meniscectomy were analyzed with a prospective randomized control design for 12 months postoperatively. The demographic characteristics, Kellgren-Lawrence grade, and location of the injury lesion (medial or lateral meniscus) were not significantly different between the groups. Using 3D volume analysis with magnetic resonance imaging (MRI), the meniscus-removing ratio during the operative procedure and the meniscus defect-filling ratio were measured during the 12-month postoperative period. Clinically, the visual analog scale, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score were evaluated. The Whole-Organ Magnetic Resonance Imaging Score (WORMS) and Genovese grade were also evaluated using MRI. Results: In the 3D volume analysis, the average meniscus-removing ratio during surgery was not significantly different between the groups (-9.3% vs. -9.2%, p = 0.984). The average meniscus defect-filling ratio during the postoperative 12-month period was 7.5% in the scaffold group and -0.4% in the meniscectomy group (p < 0.001). None of the clinical results were significantly different between the scaffold and meniscectomy groups at 12 months postoperatively. The average change in the total WORMS score was not significantly different between the groups (0 vs. 1.9, p = 0.399). The Genovese grade of the implanted collagen scaffold did not significantly change during the follow-up period in terms of morphology and size (p = 0.063); however, the grade significantly improved in terms of signal intensity (p = 0.001). Conclusions: Definite meniscal regeneration and stable scaffold incorporation were observed after collagen-based meniscal scaffold implantation in Asian patients during 12 months of follow-up. A long-term follow-up study with a larger cohort is required to determine the advantages of collagenous meniscal scaffold implantation in Asian patients.

Phase 1/2a Study of Rivoceranib, a Selective VEGFR-2 Angiogenesis Inhibitor, in Patients with Advanced Solid Tumors.

Purpose: To report the results from an early-phase study of rivoceranib, an oral tyrosine kinase inhibitor highly selective for vascular endothelial growth factor receptor 2, in patients with advanced solid tumors. Materials and Methods: In this open-label, single-arm, dose-escalating, multicenter three-part phase 1/2a trial, patients had advanced solid tumors refractory to conventional therapy. Part 1 evaluated the safety and pharmacokinetics of five ascending once-daily doses of rivoceranib from 81 mg to 685 mg. Part 2 evaluated the safety and antitumor activity of once-daily rivoceranib 685 mg. Part 3 was conducted later, due to lack of MTD determination in part 1, to evaluate the safety and preliminary efficacy of once-daily rivoceranib 805 mg in patients with unresectable or advanced gastric cancer. Results: A total of 61 patients were enrolled in parts 1 (n=25), 2 (n=30), and 3 (n=6). In parts 1 and 2, patients were white (45.5%) or Asian (54.5%), and 65.6% were male. The most common grade ≥3 adverse events (AEs) were hypertension (32.7%), hyponatremia (10.9%), and hypophosphatemia (10.9%). The overall response rate (ORR) was 15.2%. In part 3, dose-limiting toxicities occurred in 2 out of 6 patients: grade 3 febrile neutropenia decreased appetite, and fatigue. The ORR was 33%. Conclusion: The recommended phase 2 dose of rivoceranib was determined to be 685 mg once daily, which showed adequate efficacy with a manageable safety profile. (NCT01497704 and NCT02711969).

Similar Midterm Outcomes of Total Knee Arthroplasties with Anterior and Posterior Tibial Slopes Performed on Paired Knees at a Minimum Follow-up of 5 Years.

A small posterior tibial slope (PTS) is generally recommended in posterior stabilized (PS) total knee arthroplasty (TKA). An unwanted anterior tibial slope (ATS), which can affect postoperative results, may be created in PS TKA because of the inaccuracy of surgical instruments and techniques, as well as high interpatient variability. We compared midterm clinical and radiographic results of PS TKAs with ATS and PTS performed on paired knees using the same prosthesis. One-hundred-twenty-four patients who underwent TKAs with ATS and PTS on paired knees using ATTUNE posterior-stabilized prostheses were retrospectively reviewed after a minimum follow-up period of 5 years. The mean follow-up period was 5.4 years. The Knee Society Knee and Function scores, Western Ontario and McMaster Universities Osteoarthritis Index, Feller and Kujalar scores, and range of motion (ROM) were evaluated. The preferred TKA out of ATS and PTS was also investigated. The hip-knee-ankle angle, component positions, tibial slope, posterior femoral offset, Insall-Salvati ratio, and knee sagittal angle were measured by radiography. There were no significant differences in the clinical results, including ROM, between TKAs with ATS and PTS preoperatively and at the last follow-up. Regarding patient preference, 58 patients (46.8%) were satisfied with bilateral knees, 30 (24.2%) preferred knees with ATS, and 36 (29%) preferred knees with PTS. There was no significant difference in the rate of preference between TKAs with ATS and PTS (p = 0.539). Except for the postoperative tibial slope (-1.8 vs. 2.5 degrees, p < 0.001), there were also no significant differences in the radiographic results, including the knee sagittal angle, preoperatively and at the last follow-up. The midterm outcomes were similar between PS TKAs with ATS and PTS performed on paired knees at a minimum of 5 years of follow-up. Nonsevere ATS did not affect midterm outcomes in PS TKA with proper soft tissue balancing and the current prosthesis of improved design. However, a long-term follow-up study is required to confirm the safety of nonsevere ATS in PS TKA. LEVEL OF EVIDENCE:: III.

Anatomic femoral tunnel position in medial patellofemoral ligament reconstruction: anterior versus posterior.

BACKGROUND: This study aimed to compare the clinical and radiological outcomes of medial patellofemoral ligament reconstruction (MPFLR) between anatomic femoral tunnel positions at anterior and posterior footprints. METHODS: Fifty-seven patients who underwent MPFLR for patellofemoral instability with anterior or posterior femoral tunnels between 2014 and 2021 with at least 2 years of follow-up were retrospectively analyzed. Based on postoperative images, the femoral tunnel positions anterior to the line connecting the adductor tubercle and medial epicondyle were assigned to the anterior group, group A, and those posterior to the line to the posterior group, group P. Thirty-two patients were included in group A (mean age, 22.4 ± 8.8 years), and another 25 patients were included in group P (mean age, 21.1 ± 6.1 years). The International Knee Documentation Committee (IKDC) subjective score, Lysholm score, Tegner activity score, Kujala score, and complications were evaluated. Radiologically, the Caton-Deschamps index (CDI), patellar tilt angle, and patellofemoral osteoarthritis (PFOA) using the Kellgren-Lawrence (KL) scale were evaluated. The patellofemoral cartilage status according to the International Cartilage Repair Society (ICRS) grade, bone contusion, femoral tunnel enlargement, and MPFL graft signal intensity were also evaluated. RESULTS: All clinical scores significantly improved in both groups (p < 0.01). No differences were noted between the two groups in terms of their preoperative demographic data, postoperative clinical scores (IKDC, Lysholm, Tegner, and Kujala), complications, or radiological findings (CDI, patellar tilt angle, PFOA, bone contusion, femoral tunnel enlargement, and graft signal intensity). The ICRS grade for the medial facet of the patella progressed in group A (30%, p = 0.02) but not in group P (18%, p = n.s.). Additionally, no significant differences were observed in the other compartments of the patellofemoral joint. CONCLUSIONS: The clinical outcomes were significantly improved in both groups; however, MPFLR with anterior femoral tunnel position had worse cartilage status on the medial facet of the patella than the posterior femoral tunnel position. LEVEL OF EVIDENCE: Level III.

Surgical accuracy of coronal and sagittal alignment in conventional closed-wedge high tibial osteotomy after computer-assisted surgery experience.

BACKGROUND: Although intraoperative navigation can improve the surgeon's proficiency, no studies have analyzed postoperative outcomes of high tibial osteotomy (HTO) after computer-assisted surgery (CAS) experience. The present study compared the clinical and radiographic results between conventional and CAS closed-wedge (CW) HTOs after CAS experience. METHODS: Each of the 50 conventional and CAS CW HTOs performed by single surgeon between 2015 and 2017 were included. The surgeon had experience of 140 cases of CAS CW HTOs before the study period. The groups were not different in terms of demographics. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were investigated. Radiographically, the mechanical axis (MA), change in posterior tibial slope angle (PTS), and parallel angle were evaluated. The proportions of inlier groups for the postoperative MA (within valgus 2° ± 3°), change in the PTS (within ± 3°), and parallel angle (< 3°) were compared. RESULTS: There were no significant differences in postoperative clinical results between the conventional and CAS groups. The MA was appropriately corrected in both groups (2.4° versus 2.9°, p = 0.317). The amount of change in PTS was significantly greater in the conventional group (-2.2° versus -0.8°, p = 0.018). The parallel angle was 5.3° in the conventional groups and 3.1° in the CAS group (p = 0.003). The proportion of inlier group was not significantly different in the postoperative MA (72% versus 78%) and change in the PTS (52% versus 66%). The proportion of inlier for the parallel angle was significantly lower in the conventional group (36% versus 60%, p = 0.027). CONCLUSIONS: The surgical proficiency after CAS experience could cover the advantages of an intraoperative navigation in coronal adjustment, not in the sagittal adjustments in CW HTOs. A larger cohort with multiple surgeons in multiple centers would be required to identify the general trend. STUDY DESIGN: Level of evidence III.

Learning curve for robot-assisted knee arthroplasty; optimizing the learning curve to improve efficiency.

The introduction of robot-assisted (RA) systems in knee arthroplasty has challenged surgeons to adopt the new technology in their customized surgical techniques, learn system controls, and adjust to automated processes. Despite the potential advantages of RA knee arthroplasty, some surgeons remain hesitant to adopt this novel technology owing to concerns regarding the cumbersome adaptation process. This narrative review addresses the learning-curve issues in RA knee arthroplasty based on the existing literature. Learning curves exist in terms of the operative time and stress level of the surgical team but not in the final implant positions. The factors that reduce the learning curve are previous experience with computer-assisted surgery (including robot or navigation systems), specialization in knee surgery, high volume of knee arthroplasty, optimization of the RA workflow, sequential implementation of RA surgery, and consistency of the surgical team. Worse clinical outcomes may occur in the early postoperative period, but not in the later period, in RA knee arthroplasty performed during the learning phase. No significant differences were observed in implant survival or complication rates between the RA knee arthroplasties performed during the learning and proficiency phases.

Predictors of Recurrent Flexion Contracture after Total Knee Arthroplasty in Osteoarthritic Knees with Greater Than 15° Flexion Contracture.

Background: This study aimed to analyze the risk factors that predict recurrent flexion contracture (FC) after total knee arthroplasty (TKA) in osteoarthritic knees with FC ≥ 15°. Methods: Data from a consecutive cohort comprising 237 TKAs in 187 patients with degenerative osteoarthritis, preoperative FC ≥ 15°, and a minimum follow-up period of 2 years were retrospectively reviewed. Preoperative FC was corrected intraoperatively from 0° to 5°. The incidence of recurrent FC (FC ≥ 10°) at 2 years postoperatively was investigated. Potential risk factors predicting recurrent FC including age, sex, body mass index, unilateral TKA, severity of preoperative FC, 3-month postoperative residual FC, γ angle, change in posterior femoral offset ratio, and lumbar degenerative kyphosis (LDK) were analyzed using logistic regression analysis. The post-hoc powers for the identified factors were then determined. Results: Forty-one knees (17.3%) with recurrent FC were identified. Risk factors with sufficient power for recurrent FC were unilateral TKA, severity of preoperative FC, residual FC at 3 months postoperatively, and LDK (odds ratios of 3.579, 1.115, 1.274, and 3.096, respectively; p < 0.05; power ≥ 86.1). Conclusions: Recurrent FC can occur in TKAs with the risk factors including unilateral TKA, severe preoperative FC, residual FC at 3 months postoperative, and LDK despite appropriate intraoperative correction. Surgical strategies and rehabilitation protocols used in managing FC should be applied in TKA cases with risk factors for recurrent FC.

Costal chondrocyte-derived pellet-type scaffold-free autologous chondrocyte implantation provided acceptable mid-term outcomes in osteochondral defects with up to 10-mm depth.

PURPOSE: To evaluate clinical, radiographic, and magnetic resonance (MR) results of costal chondrocyte-derived pellet-type scaffold-free autologous chondrocyte implantation (CCP-ACI) in osteochondral defects (ODs) up to 10-mm depth during 5 years of follow-up. METHODS: Ten patients with CCP-ACI performed in ODs with depth up to 10 mm were retrospectively analyzed. The minimum follow-up period was 5 years. The median age was 36.5 (range 20-55) years. The median size and the depth of the OD lesion were 4.25 cm2 (range 2-6) and 7.0 mm (6-9), respectively. Clinically, the International Knee Documentation Committee, Lysholm, and visual analog scale pain scores were evaluated. Radiographically, the hip‒knee‒ankle (HKA) angle and the Kellgren‒Lawrence (K‒L) grade were assessed. On MR imaging, the magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and the defect depth were evaluated. RESULTS: All average clinical scores improved significantly by 1, 2, and 5 years postoperatively. The average HKA angle and the proportion of K‒L grade did not change significantly within 5 years. The median total MOCART scores were 50 (range 45-65), 50 (35-90), 57.5 (40-90), and 65 (50-85) at 6 months, 1 year, 2 years, and 5 years postoperatively, respectively (p = 0.001), with significant improvement at 2 years compared to that at 6 months postoperatively. The signal intensity of the repair tissue and subchondral change significantly improved from 10 (range 10-10) to 12.5 (10-15) (p = 0.036), and from 10 (10-10) to 17.5 (0-20) (p = 0.017), respectively. Significant improvements were seen at 5 years postoperatively for the former and at 2 years postoperatively for the latter. The average depths on MR imaging were 6.7, 6.7, 6.8, 6.6, and 6.6 mm preoperatively and at 6 months, 1 year, 2 years, and 5 years postoperatively with no significant changes (n.s). CONCLUSION: CCP-ACI provided acceptable mid-term outcomes in ODs up to 10-mm in depth without bone grafting despite of no scaffold. The procedure can be one of minimally invasive treatment options for ODs without scaffold-related problems. LEVEL OF EVIDENCE: IV.

The Mediating Effects of Social Networks and Wisdom on the Relationship between Lifestyle Habits and Healthy Aging in Older Adults with Chronic Diseases.

BACKGROUND: The purpose of this study was to analyze the mediating effects of social networks and wisdom on the relationship between lifestyle habits and healthy aging in older adults with chronic diseases. METHODS: Participants were 120 community-dwelling older adults aged 65 and older with at least one chronic disease. Data were collected from elderly people by visiting nursing care worker training centers, senior centers, social gatherings, and home welfare centers in D, G, and S cities, with a questionnaire of lifestyle habits, social networks, wisdom and healthy aging, and general characteristics. RESULTS: There were differences in the degree of healthy aging according to age (F = 3.76, p = 0.026), spousal relationship (t = 3.11, p = 0.002), education (F = 9.08, p < 0.001), number of diseases (F = 8.65, p < 0.001), and economic level (t = -2.45, p = 0.016). The most common diseases among the subjects were hypertension, hyperlipidemia, joint diseases and diabetes mellitus. Social networks (ß = 0.46, p < 0.001) and wisdom (ß = 0.55, p < 0.001) had partial mediating effects (z = 4.15, p < 0.001; z = 5.11, p < 0.001) on the relationship between subjects' lifestyle habits and healthy aging. CONCLUSIONS: To increase the degree of healthy aging of subjects, it is necessary to establish a mediating intervention program that manages to have good lifestyle habits in daily life, increase social networks, and become wise.

Aseptic survival of the 1.5-stage exchange arthroplasty for periprosthetic joint infection was acceptable when using an autoclaved femoral component and a new polyethylene insert.

PURPOSE: To investigate the aseptic survival of 1.5-stage exchange arthroplasty for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). METHODS: Eighty-eight cases of 1.5-stage exchange arthroplasty for PJI without reinfection were retrospectively analysed. The autoclaved femoral component and new polyethylene insert (PE) were implanted using antibiotic mixed cement. The explanted tibial component was not reinserted. The Western Ontario and McMaster Universities Osteoarthritis Index and range of motion were clinically evaluated preoperatively and at the last follow-up (the last time for the implant in situ). Radiographically, hip-knee-ankle angle (HKA) and component positions were measured preoperatively, postoperatively (1 month after the 1.5-stage exchange arthroplasty), and at the last follow-up. The survival rate was analysed using the Kaplan-Meier method, in which failure was defined as reoperation due to aseptic failure. Mean period to failure and failure site were analysed. Factors affecting survival were investigated in terms of demographics and inappropriateness of the postoperative HKA (HKA > 0 ± 3°) and component positions (α angle > 95 ± 3°, ß angle > 90 ± 3°, γ angle > 3 ± 3°, and δ angle > 87 ± 3°). RESULTS: The spacer in-situ time was 3.7 years (0.2-6.4). The clinical results improved hip-knee-ankle significantly at the last follow-up. Radiographically, the average HKA was valgus 0.1° postoperatively. The average α, ß, γ, and δ angles of the postoperative component positions were 95.9°, 90.4°, 3.8°, and 86.7°, respectively. The 1-, 2-, and 5-year postoperative survival rates were 90.9%, 86.4%, and 80.6%, respectively. The mean period to failure was 2.0 years (0.2-5.3). There were 18 cases of aseptic loosening (20.8%), occurring on both the femur and tibial sides in 1 knee, and only on the tibial side in 17 knees. Inappropriate coronal position of the PE (ß angle > 90 ± 3°) was a significant factor affecting survival (odds ratio = 5.491; p = 0.011). CONCLUSION: The aseptic survival of the 1.5-stage exchange arthroplasty was acceptable when using an autoclaved femoral component and new PE. The appropriate coronal position of the PE helps ensure favourable survival of 1.5-stage exchange arthroplasty. LEVEL OF EVIDENCE: IV.

Nonoperative Treatment for Traumatic Partial Graft Rupture After Anterior Cruciate Ligament Reconstruction: A 2-Year Follow-up Study.

Background: There are no studies on the nonoperative treatment of traumatic partial anterior cruciate ligament (ACL) graft rupture. Purpose/Hypothesis: The purpose of this study was to compare the clinical and radiological outcomes and failure rates between nonoperative treatment and revision ACL reconstruction for traumatic partial ACL graft rupture. We hypothesized that the outcomes and failure rates would be comparable and that nonoperative treatment of traumatic partial ACL graft rupture can produce satisfactory outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively evaluated 2114 patients treated for isolated ACL rupture between January 2000 and June 2020. Patients with traumatic partial graft rupture after ACL reconstruction with minimum 2-year follow-up data were included. Patients who met all the following conditions were candidates for nonoperative treatment: (1) Lachman or pivot-shift grade 0 or 1 at 6 months after ACL reconstruction, (2) ACL graft with low to intermediate signal intensity on 1-year postoperative magnetic resonance imaging (MRI), and (3) MRI after reinjury showing definite evidence of trauma, some fibers remaining in continuity of the ACL graft, and no anterior tibial subluxation in the sagittal plane. The patients were divided into 2 groups according to treatment method: nonoperative treatment (group A) and revision ACL reconstruction (group B). Clinical scores, laxity test results, radiological outcomes, and graft failures were compared between the groups. Results: In total, 47 patients had traumatic partial graft rupture (group A, n = 10; group B, n = 37). There were no significant differences between the 2 groups in terms of clinical scores, laxity tests, radiological outcomes, or graft failure. Conclusion: The clinical and radiological outcomes of nonoperative treatment of traumatic partial graft rupture after ACL reconstruction were comparable with those of revision ACL reconstruction. Nonoperative treatment of traumatic partial ACL graft rupture can produce satisfactory outcomes in selected patients.

Corrigendum to "Infection and Instability Increasing the Risk of Patella Baja and Pseudo-Patella Baja after Revision Total Knee Arthroplasty".

[This corrects the article on p. 71 in vol. 15, PMID: 36778990.].

Effects of General Characteristics, Emotional Labor, Empathy Ability, and Wisdom on the Psychological Well-Being of Female Caregivers Visiting the Homes of Vulnerable Care Recipients and the Elderly.

The purpose of this study is to analyze how general characteristics, emotional labor, empathy ability, and wisdom affect the psychological well-being of female caregivers. The research design is a descriptive correlational study. Data were collected using a self-report questionnaire, and analyzed using the SPSS Windows 27.0 program for hierarchical regression analysis. The results showed that there were differences in psychological well-being according to the work experience, education, and monthly income of 129 participants. In the analysis of the factors affecting the participants' psychological well-being, model 1 showed 18.9% explanatory power with educational experience (ß = -0.23, p = 0.012) and monthly income (ß = 0.25, p = 0.007). In model 2, educational experience (ß = -0.23, p = 0.004), monthly income (ß = 0.20, p = 0.017), and emotional labor (ß = -0.41, p < 0.001) were the affecting factors, and the explanatory power increased by 16.1%, showing 35.0% overall. In model 3, educational experience (ß =-0.28, p < 0.001), emotional labor (ß = -0.35, p < 0.001), empathy ability (ß = 0.23, p = 0.001), and wisdom (ß = 0.52, p < 0.001) were the affecting factors, and the explanatory power increased by 36.9%, showing 71.9% overall. To enhance the psychological well-being of the participants, the head of the caregiving center should consider the education and income of caregivers. The center should also operate programs and prepare policies to reduce emotional labor and enhance empathy ability and wisdom.

Additional anteromedial staple fixation prevents changes in the posterior tibial slope in retrotuberosity bi-planar open-wedge high tibial osteotomy.

PURPOSE: To compare the changes in posterior tibial slope (PTS) between retrotuberosity biplane open-wedge high tibial osteotomies (RT-OWHTOs) with and without additional anteromedial staple fixation. METHODS: Seventy-nine and 77 cases of RT-OWHTOs without (Group N) and with (Group S) additional staple fixation, respectively, were retrospectively reviewed. All procedures were performed using a locking spacer plate. Demographics and preoperative knee condition were similar between the groups. Clinically, the Western Ontario and McMaster Universities Arthritis Index and range of motion were evaluated preoperatively and 2 years postoperatively. Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and PTS were evaluated preoperatively and within 2 years postoperatively. Hinge fractures were investigated using computed tomography at 2 weeks postoperatively. PTS loss was defined as the difference between the corresponding values at 2 weeks and 2 years postoperatively. The incidence of PTS failure (PTS loss ≥ ± 3°) was also investigated. RESULTS: The clinical results were not significantly different between groups N and S preoperatively and 2 years postoperatively. There were no significant differences in the MA, MPTA, and PTS between the groups preoperatively and 2 weeks postoperatively; changes in these variables did not differ significantly between the groups. The incidence of hinge fractures, all of which were categorized as Takeuchi type 1, did not differ significantly. PTS loss within 2 years postoperatively was significantly greater in group N than in group S (1.0° vs. 0.1°; p < 0.01). The incidence of the PTS failure was 16.5% (13/79) and 2.6% (2/77) in groups N and S, respectively (p < 0.01). CONCLUSION: Additional anteromedial staple fixation could prevent changes in the PTS in RT-OWHTO. It is a simple method for preventing an increase in the PTS after RT-OWHTO. LEVEL OF EVIDENCE: III.

Infection and Instability Increasing the Risk of Patella Baja and Pseudo-Patella Baja after Revision Total Knee Arthroplasty.

Background: Patella baja with patellar tendon shortening due to traumatic or ischemic injury is a widely known complication after primary total knee arthroplasty (TKA). Pseudo-patella baja may arise from the elevation of the joint line after excessive distal femoral resection. The maintenance of original patellar height is important in revision TKA because postoperative patella baja and pseudo-patella baja can cause inferior biomechanical and clinical results. We investigated the incidence and risk factors of patella baja and pseudo-patella baja after revision TKA. Methods: We retrospectively reviewed data for 180 revision TKAs. Patella baja was defined as a truly low-lying patella with an Insall-Salvati ratio (ISR) of < 0.8 and a Blackburne-Peel ratio (BPR) of < 0.54. Pseudo-patella baja was defined as a relatively low-lying patella compared to the joint line within the normal range of ISR and with a BPR of < 0.54. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. Risk factors increasing the incidence of patella baja and pseudo-patella baja after revision TKA were evaluated using multiple regression analysis. Results: Before revision TKA, 169 knees did not exhibit patella baja or pseudo-patella baja, while 9 knees showed patella baja and 2 knees exhibited pseudo-patella baja. At 2 years after revision TKAs, 25 knees (13.9%) showed patella baja and 23 knees (12.8%) exhibited pseudo-patella baja. Despite no differences in the postoperative WOMAC score between groups with and without patella baja and pseudo-patella baja, the postoperative ROM was significantly smaller in the group with patella baja (113.3°) or pseudo patella baja (110.5°) than in the normal group (122.0°). Infection as the cause of revision TKA increased the risk of patella baja (odds ratio, 10.958; p < 0.001), and instability increased the risk of pseudo-patella baja (odds ratio, 11.480; p < 0.001). Conclusions: Infection and instability resulted in increases in the incidence of patella baja and pseudo-patella baja after revision TKA. Information about the risk factors of patella baja and pseudo-patella baja will help TKA surgeons plan the height of the patella after revision TKA and improve clinical outcomes.

Intraoperative Assessment of Gap Balancing in Total Knee Arthroplasty Using Navigation with Joint Stability Graphs.

The purpose of this study was to assess continuous gaps in the replaced knee throughout the full range of motion (ROM) after total knee arthroplasty (TKA) using a joint stability graph, and to analyze the gap laxity in the mid-flexion range. Ninety-three TKAs were performed using imageless navigation with a joint stability graph. While positioning guides for each respective cut, the surgeon can safely preview the resection's impact for the resulting joint gaps and control the soft tissue balance at the knee flexion of 0° (extension) and 90° (flexion). The gaps between the femoral component and insert were evaluated throughout the full ROM using the joint stability graph. The mechanical axis (MA) and change of joint line height were radiographically evaluated. Posthoc power analyses using a significant α value of 0.05 were performed on the proportion of the mid-flexion instability as a primary outcome to determine whether the sample had sufficient power. The power was determined to be sufficient (100%). The flexion-extension gap differences in each medial and lateral compartment and the mediolateral gap differences in flexion and extension were all ≤3 mm. None of the knees had mid-flexion instability, which is defined by a peak mid-flexion gap that is 3 mm greater than the smaller value of flexion or extension gap. The average MA was well corrected from varus 11.4° to varus 1.0° postoperatively. The proportion of postoperative well-aligned knees (MA ≤ 3°) was 87.1%. The joint line height was well preserved (14.7 vs. 14.8 mm, p = 0.751). The joint stability graph in TKA using the navigation can effectively evaluate the continuous gap throughout the ROM, including the mid-flexion range. Mid-flexion instability was uncommon in primary TKAs with appropriate alignment and proper preservation of the joint line. The Level of evidence for the study is IV.

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle.

PURPOSE: To analyze the incidence of intraoperative mid-flexion laxity using continuous flexion-arc gap assessment, risk factors for mid-flexion laxity, and clinical results in navigation-assisted total knee arthroplasty (TKA). METHODS: Ninety posterior-stabilized TKAs were performed under navigation guidance for patients with degenerative arthritis and varus deformity. Intraoperatively, the gap between the trial femoral component and insert was evaluated in the navigation system with continuous flexion-arc gap assessment. Each medial and lateral gap at flexion (90°) and extension (0°) were made to be less than 3 mm. Mid-flexion laxity was determined when the gap in the flexion range between 15° and 60° was 3 mm or more. The proportion of knees with mid-flexion laxity was investigated. The factors affecting mid-flexion laxity were identified in terms of demographics, preoperative convergence angle, and change in joint line height and posterior femoral offset. The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index were evaluated. RESULTS: There were 31 cases (34.4%) of lateral mid-flexion laxity (average peak mid-flexion gap = 3.7 mm). The other 59 cases did not show mid-flexion laxity. The preoperative convergence angle was the only significant factor affecting lateral mid-flexion laxity (odds ratio = 1.466, p = 0.002). There were no significant differences in the clinical results between the groups with and without mid-flexion laxity. CONCLUSIONS: The continuous flexion-arc gap assessment was useful in evaluating mid-flexion laxity using navigation-assisted TKA. The preoperative convergence angle, reflecting soft-tissue laxity, can be a practical and simple radiographic finding for predicting lateral mid-flexion laxity. LEVEL OF EVIDENCE: IV.

Closed-wedge high tibial osteotomy is more advantageous to maintain the correction than open-wedge high tibial osteotomy in osteopenic patients.

PURPOSE: To compare the incidence of correction loss and survival rate between closed-wedge and open-wedge high tibial osteotomies (CWHTO and OWHTO, respectively) in patients with osteopenic and normal bone. METHODS: Retrospective review was conducted for 115 CWHTOs and 119 OWHTOs performed in osteopenic patients [- 2.5 < Bone mineral density (BMD) T scores ≤ - 1] and 136 CWHTOs and 138 OWHTOs performed in normal patients (BMD T score > - 1) from 2012 to 2019. Demographics were not different between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively). Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS) were evaluated pre- and postoperatively (2 weeks after HTO). The occurrence of hinge fractures was investigated using radiographs taken on the operation day. The correction change was calculated as the last follow-up value minus postoperative MPTA. Correction loss was defined when the correction change was ≥ 3°. The survival rate (failure: correction loss) was investigated. RESULTS: There were no significant differences in the pre and postoperative MA, MPTA, PTS, and value changes between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively); the incidence of unstable hinge fractures also did not differ significantly (CWHTO vs. OWHTO = 7 vs. 7.6% in osteopenic patients; 2.9 vs. 3.6% in normal patients; n.s., respectively). The average correction change (CWHTO = - 0.6°, OWHTO = - 1.3°, p = 0.007), incidence of correction loss (CWHTO = 1.7%, OWHTO = 9.2%, p = 0.019), and 5-year survival rates (CWHTO = 98.3%, OWHTO = 90.8%, p = 0.013) differed significantly in osteopenic patients; there were no significant differences in these results in normal patients (n.s., respectively). CONCLUSION: CWHTO was more advantageous than OWHTO regarding the correction loss in osteopenic patients. Intra- and postoperative care that consider poor bone quality will be required when performing OWHTOs in osteopenic patients. LEVEL OF EVIDENCE: III.

Medial proximal tibial resorption after total knee arthroplasty according to the design of the cobalt chrome tibial baseplate.

PURPOSE: A new tibial baseplate of the cobalt-chrome (CoCr) prosthesis has an enhanced design with additional cement pockets and undersurface with increased roughness compared with the original baseplate. This study aimed to compare the incidence of medial proximal tibial resorption (MPTR) in total knee arthroplasties (TKAs) with the original and new CoCr tibial baseplates. METHODS: Each of 200 posterior stabilized TKAs with the original (Group O) and new (Group N) CoCr tibial baseplates with a minimum follow-up period of 2 years were retrospectively reviewed. The matches were made according to age, sex, body mass index, and severity of varus deformity. The occurrence of MPTR was investigated with a radiograph at 2 years postoperatively. MPTR was categorized as type U (resorption under the tibial baseplate; associated with stress shielding), C (resorption around the penetrated cement under the baseplate; associated with thermal necrosis), and M (resorption on the medial tibial cortex without extension to the baseplate; associated with bony devascularization). RESULTS: The incidence of MPTR was 35% in group O and 24% in group N (p = 0.021) at postoperative 2 years. The U type of MPTR occurred more frequently in group O (26 vs. 15%, p = 0.009). There were no significant differences in the incidence of types C and M MPTR. CONCLUSION: The modified design of the CoCr tibial baseplate affected the incidence of MTPR. The new tibial baseplate was more advantageous in preventing MPTR than the original baseplate in TKAs using the CoCr prosthesis. LEVEL OF EVIDENCE: III.

The Mediating Effect of Self-Efficacy and Coping Strategy in Relation to Job Stress and Psychological Well-Being of Home-Visiting Care Workers for Elderly during the COVID-19 Pandemic.

The purpose of this study was to analyze the mediating effect of self-efficacy and coping strategy in the relationship between job stress and the psychological well-being of care workers. The subjects were 112 home-visiting care workers, and data were collected at four home-visiting nursing centers in a metropolitan city and a small and medium-sized city from July to August 2022. The collected data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation co-efficient, multiple linear regression, and Sobel test. The mean score of psychological well-being was 3.33 ± 0.46 out of a possible 5. The subject's psychological well-being was correlated with self-efficacy (r = 0.64, p < 0.001), problem-solving-focused coping (r = 0.58, p < 0.001), social-support-seeking coping (r = 0.34, p < 0.001), job stress (r = -0.31, p = 0.001), avoidance-focused coping (r = -0.37, p < 0.001). Self-efficacy (Z = -4.92, p < 0.001), problem-solving-focused coping (Z = -2.56, p = 0.010), and avoidance-focused coping (Z = -3.07, p = 0.002) had a mediating effect in the relationship between job stress and psychological well-being of the subjects during the COVID-19 pandemic. Based on these results, the psychological well-being nursing intervention program for home-visiting care workers need to include job stress, problem-solving-focused coping, and avoidance-focused coping.