Enhancing the Unicompartmental Knee Arthroplasty Safety via Finite Element Analysis of Coronary Plane Alignment: A Case Report.

Although Oxford unicompartmental knee arthroplasty is often used to successfully treat patients with knee osteoarthritis isolated at the medial compartment, we present a case of fracture just below the tibial keel caused by either a shift in medial loading position or an increased amount of tibial osteotomy. Finite element analysis was used to determine which factor was more important. First, a 3D-surface model of the patient's tibia and the implant shape were created using computed tomography-Digital Imaging and Communications in Medicine (CT-DICOM) data taken preoperatively. The finite element analysis found that following unicompartmental knee arthroplasty, the cortical stress (normal, 5.8 MPa) on the medial tibial metaphyseal cortex increased as the load point moved medially (3 and 12 mm medially: 7.0 and 10.7 MPa, respectively) but was mild with increased tibial bone resection (2 and 6 mm lower: 6.1 and 6.5 MPa, respectively). Implanting the femoral component more medially than the preoperative plan increases stresses in the medial cortex of the tibia and may cause fractures.

Impact of implant positions in total knee arthroplasty on the postoperative knee kinematics of tibial rotation.

Introduction: In total knee arthroplasty (TKA), the implant positions and knee kinematics, as well as the manifestation of medial pivot motion, play pivotal roles in determining postoperative clinical outcomes. The purpose of the current study was to analyze the correlation between knee kinematics, which was measured during TKA and implant positions derived using computed tomography (CT) examination after TKA. Methods: This study comprised 64 patients (76 knees) who underwent primary TKA between 2015 and 2022. A navigation system was used in TKA procedures, and intraoperative knee kinematics were automatically calculated with it. Utilizing three-dimensional evaluation software, positioning of implants was quantified with CT images taken pre- and post-operatively. Multiple regression analyses were employed to explore the impact of femoral component position (FP) and tibial component position (TP) on knee kinematics, focusing on the extent of tibial rotational motion (TRM) during passive knee motion. Results: FP affected TRM between knee extension and 90° flexion (p = 0.003, 95 % confidence interval [CI]: 0.315-1.384) and between knee extension and full flexion (p = 0.0002, 95 % CI: 0.654-1.844) after TKA. FP in internal rotation positively affected internal TRM after TKA. TP was not associated with TRM. Conclusions: Findings of the current study suggest that FP in internal rotation positively impacts knee kinematics after TKA.

Implications of the diagnosis of locomotive syndrome stage 3 for long-term care.

Objectives: Locomotive syndrome stage 3 (LS3), which has been established recently, may imply a greater need for care than LS stage 0 (LS0), LS stage 1 (LS1), and LS stage 2 (LS2). The relationship between LS3 and long-term care in Japan is unclear. Therefore, this study aimed to examine this relationship. Methods: A total of 531 patients (314 women and 217 men; mean age, 75 years) who were not classified as requiring long-term care and underwent musculoskeletal examinations in 2012 were grouped according to their LS stage. Group L comprised patients with LS3 and Group N comprised those with LS0, LS1, and LS2. We compared these groups according to their epidemiology results and long-term care requirements from 2013 to 2018. Results: Fifty-nine patients (11.1%) were diagnosed with LS3. Group L comprised more patients (50.8%) who required long-term care than Group N (17.8%) (P < 0.001). Group L also comprised more patients with vertebral fractures and knee osteoarthritis than Group N (33.9% vs 19.5% [P = 0.011] and 78% vs 56.4% [P < 0.001], respectively). A Cox proportional hazards model and Kaplan-Meier analysis revealed a significant difference in the need for nursing care between Groups L and N (log-rank test, P < 0.001; hazard ratio, 2.236; 95% confidence interval, 1.451-3.447). Conclusions: Between 2012 and 2018, 50% of patients with LS3 required nursing care. Therefore, LS3 is a high-risk condition that necessitates interventions. Approaches to vertebral fractures and osteoarthritis of the knee could be key.

Femoral trochlear groove cartilage damage after open-wedge high tibial osteotomy is associated with the change in patellar height relative to the femoral condyle.

BACKGROUND: Medial open-wedge high tibial osteotomy (OWHTO) is performed for isolated medial compartment osteoarthritis or osteonecrosis of the knee and correction of varus deformity of the full lower extremity. OWHTO may induce sagittal parameter changes, including these in the tibial posterior slope (TPS), patellar height (PH), and patellofemoral joint problems. This study aimed to identify radiographic parameters associated with patellofemoral cartilage damage after OWHTO. HYPOTHESIS: The patellofemoral joint cartilage worsens after OWHTO and is adversely affected by PH changes. PATIENTS AND METHODS: Twenty patients (25 knees) who underwent primary OWHTO and subsequent implant removal surgery, including second-look arthroscopy for evaluation of the patellofemoral cartilage condition were enrolled. The patients were received 12 to 35 months of postoperative follow-up, and categorized into two groups according to whether patellofemoral cartilage damage worsened. TPS and PH parameters, including the Insall-Salvati, Blackburne-Peel, Caton-Deschamps, and modified Blumensaat (MBI) indices, were measured on lateral knee radiographs. The hip-knee-ankle and medial proximal tibial angles were measured using an anteroposterior radiograph of the full lower extremity. The extent of change from preoperative to postoperative (Δ) was calculated for all indices. RESULTS: Eleven knees (44%) had worsening cartilage conditions in the femoral trochlear groove, with>1-degree of deterioration in the International Cartilage Repair Society grade. The radiographic measure for predicting patellofemoral cartilage deterioration was ΔMBI (95% confidence interval [CI]: 3.53×10-14-0.812, p=0.047). PF cartilage damage tended to progress in ΔMBI<-0.145. The postoperative TPS and HKAA in patients with deterioration in patellofemoral cartilage damage was greater than that in patients without deterioration in patellofemoral cartilage damage (p=0.037 and 0.038, respectively). DISCUSSION: The patellofemoral cartilage damage tends to progress after OWHTO. ΔMBI is a factor for predicting worsening patellofemoral cartilage condition. However, attention should be paid to the excessive posterior slope as high TPS and valgus alignment as valgus HKAA because intraoperative control of MBI is impossible. LEVEL OF EVIDENCE: IV, retrospective study.

Impact of the sagittal spinopelvic and coronal lower extremity alignments on clinical outcomes after medial unicompartmental knee arthroplasty.

Introduction: We evaluated whether the clinical outcomes, including postoperative knee range of motion (ROM), after unicompartmental knee arthroplasty (UKA) were associated with the sagittal spinopelvic parameters and coronal alignment of the full lower extremity. Methods: Forty-two patients (50 knees: six men, seven knees; 36 women, 43 knees) who underwent medial UKA between April 2015 and December 2022 were included. Preoperative radiographic examinations of the index for sagittal spinopelvic alignment included the sagittal vertical axis (SVA), lumbar lordosis, sacral slope (SS), pelvic tilt (PT), and pelvic incidence. The anteroposterior hip-knee-ankle angle (HKAA) was calculated. The relationship of clinical outcomes and the risk of knee flexion angle ≤125° and knee flexion contracture ≥10° 1-year post-UKA with radiographic parameters were evaluated. Results: Preoperative HKA angle affected postoperative knee flexion angle ≤125° (p = 0.017, 95% confidence interval [CI]: 0.473-0.930) in logistic regression analysis. Patients with a knee flexion angle ≤125° had a higher preoperative HKAA (9.8 ± 3.0°), higher SVA (83.8 ± 37.0 mm), and lower SS (23.7 ± 9.0°) than those with a flexion angle >125° (preoperative HKAA: 6.6 ± 4.0°, SVA: 40.3 ± 46.5 mm, SS: 32.0 ± 6.3°) (p = 0.029, 0.012, and 0.004, respectively). PT related to postoperative knee flexion contracture ≥10° (p = 0.010, 95% CI: 0.770-0.965) in the logistic regression analysis. Patients with flexion contracture ≥10° had higher PT (35.0 ± 6.6°) and SVA (82.2 ± 40.5 mm) than those with flexion contracture <10° (PT, 19.3 ± 9.0°; SVA, 42.4 ± 46.5 mm) (p = 0.001 and 0.028, respectively). The postoperative clinical outcome was correlated with the postoperative knee flexion angle and SVA (p = 0.036 and 0.020, respectively). Conclusions: The preoperative HKAA affected postoperative knee flexion angle, and the knee flexion contracture and clinical outcomes post-UKA were associated with PT and SVA, respectively. To predict outcomes for knee ROM and clinical scores after UKA, radiographic examination, including the sagittal spinopelvic parameters and the coronal view of the full lower extremity, is essential.

Evaluation of brain activation related to resting pain using functional magnetic resonance imaging in cynomolgus macaques undergoing knee surgery.

Purpose: Functional magnetic resonance imaging (fMRI) visualizes hemodynamic responses associated with brain and spinal cord activation. Various types of pain have been objectively assessed using fMRI as considerable brain activations. This study aimed to develop a pain model in cynomolgus macaques undergoing knee surgery and confirm brain activation due to resting pain after knee surgery. Methods: An osteochondral graft surgery on the femoral condyle in the unilateral knee was performed on four cynomolgus macaques (Macaca fascicularis). Resting pain was evaluated as changes in brain fMRI findings with a 3.0-T MRI scanner preoperatively, postoperatively, and after postoperative administration of morphine. In the fMRI analysis, Z-values >1.96 were considered statistically significant. Results: Brain activation without stimulation after surgery in the cingulate cortex (3.09) and insular cortex (3.06) on the opposite side of the surgery was significantly greater than that before surgery (1.05 and 1.03, respectively) according to fMRI. After the administration of morphine, activation due to resting pain decreased in the cingulate cortex (1.38) and insular cortex (1.21). Conclusion: Osteochondral graft surgery on the femoral condyle can lead to postoperative resting pain. fMRI can reveal activation in pain-related brain areas and evaluate resting pain due to knee surgery.

Distribution of coronal plane alignment of the knee classification does not change as knee osteoarthritis progresses: a longitudinal study from the Toei study.

PURPOSE: The purpose of this study was to investigate the coronal plane alignment of the knee (CPAK) phenotypes of individuals with knee osteoarthritis (OA) progression. We hypothesized that distributions of CPAK phenotypes would be similar throughout OA progression, despite arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) changing. METHODS: A total of 248 patients (79 men and 169 women) participated in the first study in 2012 and the fifth study in 2020. Patients with progression of knee OA for eight years were included. Knee OA progression was defined as advancement from KL grade 0-2 to KL grade 3 or 4. Alignment parameters, including the aHKA, JLO, hip-knee-ankle angle (HKA), lateral distal femur angle (LDFA), medial proximal tibial angle (MPTA), and joint line convergence angle (JLCA), were measured. Changes in distribution of CPAK classifications and alignment parameters were investigated. Alignment parameters were compared using a paired t-test. Statistical significance was defined as p < 0.05. RESULTS: The study included 48 patients (60 knees). The distributions of all CPAK phenotypes were similar between 2012 and 2020. MPTA (83.7° ± 2.8° vs. 82.3° ± 4.8°, p < 0.01), aHKA (- 3.6° ± 3.8° vs. - 4.9° ± 6.2°, p = 0.01), and JLO (171.1° ± 4.6° vs. 169.5° ± 5.1°, p < 0.01) decreased significantly, and JLCA (1.17° ± 2.2° vs. 3.1° ± 4.7°, p < 0.01) and HKA (4.8° ± 3.9° vs. 8.0° ± 5.4°, p < 0.01) increased significantly. In contrast, LDFA (87.4° ± 3.2° vs. 87.2° ± 3.1°, p = n.s.) did not change significantly. CONCLUSIONS: The CPAK classification system can predict constitutional alignment, even with knee OA progression, and enables surgeons to perform individualized preoperative alignment planning according to knee phenotypes.

Relationship between the Femoral and Tibial Component Positions and Postoperative Knee Range of Motion after Posterior-Stabilized Total Knee Arthroplasty in Varus-Aligned Knees.

This study aimed to evaluate the relationship between the femoral and tibial component positions and postoperative knee range of motion after posterior-stabilized total knee arthroplasty (TKA). Forty-four patients (48 knees in total: 9 men, 9 knees; 35 women, 39 knees) who underwent posterior-stabilized TKA using a navigation system were included. The femoral and tibial component positions were measured from the preoperative and postoperative computed tomography data with three-dimensional evaluation software. We investigated the relationship between the knee range of motion, including extension restriction and maximum flexion angles at 2 years postoperatively, and the femoral and tibial component positions. Patients with knee extension restriction of 10° or more at 2 years postoperatively showed greater posterior flexion position of the tibial component than those with knee extension restriction less than 10° (6.2° and 3.9°, respectively, p=0.018). The postoperative knee flexion angle was positively associated with the internal rotational position of the femoral component (p=0.032, 95% confidence interval: 0.105-2.178). Patients with a knee flexion angle more than 120° at 2 years postoperatively had greater internal rotational position of the femoral component than those with 120° or less (5.2° and 1.5°, respectively, p=0.002). In conclusions, after posterior-stabilized TKA, the postoperative knee extension restriction angle was associated with the posterior flexion position of the tibial component, and the knee flexion angle was positively related to the internal rotational position of the femoral component.

Comparison Between the Simultaneous Reconstructions of the Anterior Talofibular Ligament and Calcaneofibular Ligament and the Single Reconstruction of the Anterior Talofibular Ligament for the Treatment of Chronic Lateral Ankle Instability.

This study aimed to evaluate the procedures of reconstruction surgery for chronic lateral ankle instability. We compared single anterior talofibular ligament reconstruction to simultaneous reconstructions of the anterior talofibular and calcaneofibular ligaments. From 2015 to 2019, 14 consecutive patients diagnosed with chronic lateral ankle instability underwent arthroscopic anterior talofibular ligament reconstruction with or without calcaneofibular ligament reconstruction after conservative treatment. Seven patients underwent single anterior talofibular ligament reconstruction (group AT), and 7 patients underwent simultaneous reconstructions of the anterior talofibular ligament and calcaneofibular ligament (group AC). The Japanese Society for Surgery of the Foot scale scores and Karlsson scores significantly improved in all patients 1 year postoperatively. The radiographic measurement of the talar tilt angle and the talar anterior drawer distance at 1 year after surgery were also significantly improved compared to preoperative values. The postoperative talar tilt angle was significantly greater in group AT (median 6°, range 3°-7°) than that in group AC (median 3°, range 2°-5°; p = .038). The postoperative talar anterior drawer distance, Japanese Society for Surgery of the Foot scale score, and Karlsson score were not significantly different between the 2 groups. We found that although the clinical outcomes after the anterior talofibular ligament reconstruction with or without the calcaneofibular ligament reconstruction for chronic lateral ankle instability were good, instability of the talar tilt angle at 1 year postoperatively in patients who underwent single anterior talofibular ligament reconstruction was greater than that in patients who underwent simultaneous anterior talofibular and calcaneofibular ligament reconstructions.

Prognostic nutritional index as a risk factor for aseptic wound complications after total knee arthroplasty.

BACKGROUND: Patients with malnutrition have a high risk of postoperative complications in total knee arthroplasty (TKA). Previously, serum albumin and total lymphocyte count were considered preoperative nutritional assessment measures. Prognostic nutritional index (PNI) is calculated by a combination of serum albumin and total lymphocyte count. This study aimed to identify the risk factors for postoperative complications after TKA, including preoperative nutritional assessment, and evaluated preoperative PNI as a predictor of postoperative complications. METHODS: One-hundred and sixty patients (234 knees) who underwent primary TKA were enrolled consecutively from 2010 to 2018. The serum albumin (g/dL) and total lymphocyte count (/mm3) were examined within 3 months before TKA; thereafter, the PNI was calculated. Postoperative aseptic wound problems, such as skin erosion and dehiscence within 2 weeks and periprosthetic joint infection after TKA were examined. RESULTS: Periprosthetic joint infections occurred in 14 knees (6.0%). Postoperative aseptic wound problems within 2 weeks were significant risk factors of periprosthetic joint infection (odds ratio; 5.10, 95% confidence interval [CI]; 1.438-18.093, p = 0.012). No significant differences were noted in the patient demographics, such as age, sex, body mass index (BMI), and comorbidities between the positive and negative groups for periprosthetic joint infection, except for the rate of aseptic operative wound problems. Furthermore, postoperative aseptic wound problems were influenced by high BMI (odds ratio; 1.270, 95% CI; 1.111-1.453, p = 0.000) and low PNI (odds ratio; 0.858, 95% CI; 0.771-0.955, p = 0.015). CONCLUSIONS: Preoperative nutritional status, indicated by PNI and BMI, was associated with postoperative wound problems within 2 weeks. Periprosthetic joint infection after TKA was associated with early postoperative aseptic wound problems.

Dependence of knee range of motion on the alignment of femoral and tibial components after medial unicompartmental knee arthroplasty.

INTRODUCTION: This study evaluated the relationship between postoperative knee flexion angles and the position of femoral and tibial components in unicompartmental knee arthroplasty (UKA). MATERIALS AND METHODS: Eighteen patients (a total of 22 knees: three men, four knees; 15 females, 18 knees) who underwent navigation-assisted UKA were included. Pre- and postoperative computed tomography images were applied on 3D software, which were matched and used to calculate the position of femoral and tibial components. Correspondingly, we investigated the relationship between the knee range of motion (ROM) at 1-year postoperative follow-up and the position of femoral and tibial components. RESULTS: At 1-year post-UKA, the knee flexion angle was associated with the posterior flexion angle of tibial components. This particular angle was significantly greater in the group with equal or greater postoperative knee ROM compared to preoperative ROM (5.2 ± 2.1°) than in the group with less postoperative knee ROM compared to preoperative ROM (2.6 ± 1.6°, p < 0.01). There was no significant difference between both groups in the femoral component position, preoperative posterior slope of the medial tibial plateau, change in the pre- to postoperative posterior tibial slope, and postoperative knee society score. CONCLUSION: The posterior flexion angle of the tibial component affected the improvement/deterioration of the postsurgery knee flexion angle in navigation-assisted UKA. For improved outcomes after UKA using navigation systems, surgeons should aim to achieve a 5° to 8° posterior flexion angle of the tibial component.

Association of knee flexion angle after posterior-stabilized total knee arthroplasty with postoperative tibial external position relative to the femur and the extent of tibial internal rotation from knee extension to flexion.

BACKGROUND: This study evaluated the relationship between preoperative and postoperative knee kinematics, moreover, investigated tibial rotational position and the extent of tibial internal rotation from knee extension to flexion as factors to obtain significant knee flexion after total knee arthroplasty (TKA). METHODS: Fifty-four patients (60 knees total; 15 males, 16 knees; 39 females, 44 knees) who underwent posterior-stabilized TKA using a navigation system were included. Intraoperative knee kinematics involving tibial rotational position relative to the femur and the extent of tibial internal rotation were examined at two time points: 1) after landmarks registration (pre-TKA) and 2) after skin closure (post-TKA). The relationship between the knee flexion angle at one year postoperatively and intraoperative tibial rotational position, or the extent of tibial rotation among several knee flexion angles calculated with a navigation system were investigated. RESULTS: The postoperative knee flexion angle was positively associated with the preoperative flexion angle and intraoperative knee kinematics at post-TKA involving tibial external position relative to the femur at knee extension and the extent of tibial internal rotation from extension to 90° of flexion or to maximum flexion. There was a positive relationship between the extent of tibial internal rotation at pre-TKA and that at post-TKA. CONCLUSIONS: The intraoperative kinematics of the extent of tibial internal rotation at post-TKA was influenced by that at pre-TKA. The greater external position of the tibia relative to the femur at knee extension and the greater extent of tibial internal rotation at post-TKA might lead to good knee flexion angle.

Relationship between Knee Osteoarthritis and Spinopelvic Sagittal Alignment in Volunteers over 50 Years of Age.

STUDY DESIGN: Large cohort study of volunteers. PURPOSE: The purpose of this study was to investigate the relationship between the severity of knee osteoarthritis, assessed using the Kellgren-Lawrence (KL) grading scale, and spinopelvic sagittal alignment in older adult volunteers. OVERVIEW OF LITERATURE: The relationship between spinopelvic alignment in the sagittal plane and knee osteoarthritis in the coronal plane is unclear. METHODS: Volunteers over 50 years of age underwent radiographic analysis. Radiographic parameters including pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), thoracic kyphosis, and sagittal vertical axis (SVA) were measured. The the three Scoliosis Research Society-Schwab sagittal modifiers (PT, SVA, PI-LL) were categorized and the KL grade was assessed. Differences in spinopelvic parameters and Oswestry Disability Index (ODI) scores among KL grades were evaluated. RESULTS: A total of 396 volunteers (160 men, 236 women; mean age, 74.4 years) were analyzed. PI-LL and PT in KL4 were significantly higher compared to that in the other KL grades. However, there were no significant group differences in SVA. In women, but not in men, higher frequencies of the worst modifier grade (++) were observed for PI-LL and PT in the KL3 and KL4 groups compared to those for the other KL grades. In women, the ODI score in KL4 was worse compared to that in the other KL grades. CONCLUSIONS: Individuals over 50 years of age with severe knee osteoarthritis had poor lumbo-pelvic sagittal alignment. Moreover, the progression severity of knee osteoarthritis had more impact onstronger relationship with lumbo-pelvic malalignment and disability-related low back pain in women than in men.

Investigation of Factors Affecting the Clinical Results of Arthroscopic Anterior Talofibular Ligament Repair for Chronic Lateral Ankle Instability.

This study aimed to examine the factors affecting the clinical outcomes of anterior talofibular ligament (ATFL) repair surgery with arthroscopy for chronic lateral ankle instability (CLAI). From 2015 to 2018, 18 consecutive patients diagnosed with CLAI after conservative treatment for ≥3 months underwent arthroscopic ATFL repair surgery using the Broström-Gould technique. Clinical scores at 1 year postoperatively on the Karlsson scoring scale (median, 85 points) and the Japanese Society for Surgery of the Foot scale (median, 90 points) were significantly improved compared with preoperative scores (median, 50 and 66 points; p < .001 and <.001, respectively). The median period to start jogging was 2 and 6 months for patients without (n = 11) and with (n = 7) cartilage damage, respectively, showing a significant difference (p = .006). Four patients with cartilage damage could not return to preinjury sports within 1 year after surgery. In the stress radiographs, the talar tilt angle (TTA) significantly improved from a median of 6° preoperatively to a median of 3.5° postoperatively (p = .002). Talar anterior drawer distance (TAD) significantly improved from a median of 6.5 mm preoperatively to a median of 4.1 mm postoperatively (p < .001). There was no significant difference in TTA or TAD between patients without and with cartilage damage. The period to start jogging postoperatively was significantly correlated with postoperative TTA and TAD. It is suggested that the postoperative period to start activities was delayed because of the larger postoperative TTA and TAD. According to our results, the postoperative period to start activities may depend on cartilage damage and instability remaining postoperatively.

A computer simulation study for preserving the tibial posterior slope in open-wedge high tibial osteotomy.

OBJECTIVE: To measure the medial opening gap and examine a technique for preserving the tibial posterior slope (TPS) in open-wedge high tibial osteotomy (OWHTO) using computer-simulated three-dimensional (3D) surgery. MATERIALS AND METHODS: This study included 24 symptomatic knees from 20 patients (7 men and 13 women; mean age, 67.9 years; range 54-89 years). Digital imaging and communications from computed tomography examination were applied to a 3D picture software program, and several anatomical landmarks were registered. Then, computer simulation of OWHTO as a virtual surgery was performed: the correction angle was decided to make the femorotibial angle 170°, and the TPS did not differ between pre- and postplanification. The distance between the proximal and distal cortices of the medial tibia was measured at three points, which were the anterior (AD), posterior (PD), and longest (LD) distance sites in the sagittal plane, using the 3D view, and the ratios of AD/PD and AD/LD were measured. The anteromedial opening gap was compared to the posteromedial gap and the longest distance gap at the osteotomy site. Spearman's rank correlation coefficient test was used in statistical analysis. RESULTS: Mean AD/PD was 0.740 ± 0.051 (range 0.651-0.850), and mean AD/LD was 0.652 ± 0.040 (range 0.571-0.768). The correction angle was not associated with the values of both AD/PD and AD/LD. CONCLUSIONS: Difference in AD/PD and AD/LD between each patient was regarded as a significant variation. Therefore, preoperative planification with 3D computer simulation to measure AD/PD and AD/LD may be helpful to avoid a significant increase in TPS.

Intraoperative bacterial contamination in total hip and knee arthroplasty is associated with operative duration and peeling of the iodine-containing drape from skin.

BACKGROUND: Surgical site infection (SSI) and periprosthetic joint infection are the most important problems after total hip arthroplasty (THA) and total knee arthroplasty (TKA). This study aimed to examine the risk factors for intraoperative bacterial contamination in THA and TKA. METHODS: One hundred and seven hips underwent THA, while 74 knees underwent TKA. After the implant was placed, a swab sample for bacterial culture was collected around the skin incision. At the time of specimen collection, patients were separated into two groups based on whether the iodine-containing drape remained adhered to the skin (group DR) or the iodine-containing drape was peeled off (group ND). Patient characteristics, including age, height, body weight, body mass index, operative duration, intraoperative blood loss, surgical procedures, and condition of the iodine-containing drape, were compared between patients with positive and negative bacterial cultures. RESULTS: In THA, which had a shorter operative duration than TKA (p < 0.001), there was one case of bacterial contamination. In TKA, there were ten cases of positive bacterial contamination, all in group ND. Postoperative SSI occurred in one case. The binomial logistic regression analyses confirmed that TKA [OR 16.562 (95% CI 2.071 to 132.430), p < 0.01] was a high risk factor of bacterial contamination compared to THA and the group ND [OR 0.000 (95% CI 0.000), p < 0.001] had a low risk of bacterial contamination compared to the group DR. In TKAs, operative duration was the risk factor of bacterial contamination [OR 1.026 (95% CI 1.000 to 1.054), p < 0.01]. CONCLUSIONS: Intraoperative bacterial contamination increases in procedures with long operating time and may be suppressed by proper use of an iodine-containing drape.

Muscle recovery at 1 year after the anterior cruciate ligament reconstruction surgery is associated with preoperative and early postoperative muscular strength of the knee extension.

BACKGROUND: The anterior cruciate ligament (ACL) injury often occurs in young athletes, but it also occurs in middle-aged individuals and the elderly during recreational sports activities. Clinical outcomes after the ACL reconstruction depend on postoperative recovery of muscular strength. The current study aimed to evaluate the recovery of knee extension and flexion strength after ACL reconstruction surgery and to examine the relationship between preoperative and postoperative muscle strength by age and the type of graft used. METHODS: From 2007 to 2010, 32 patients (17 men, 15 women; average age, 31 years; range, 14-66 years) who underwent two-bundle ACL reconstruction surgery using hamstrings, i.e., semitendinous and gracilis tendon (STG) graft, and 25 patients (15 men, 10 women; average age, 28 years; range, 15-59 years) who underwent the ACL reconstruction surgery using bone-patellar tendon-bone (BTB) graft were included in this study. The muscular strength of the knee extension and flexion compared to non-injury side was measured by an isokinetic dynamometer at a velocity at 60°/s preoperatively, and postoperative measurements were performed at 6, 9 months, and 1 year after the ACL reconstruction surgery. RESULTS: Covariates that influenced the outcome of the force of knee extension at 12 months were the preoperative muscular strength [p = 0.045, odds ratio (OR): 1.105, 95% confidence interval (CI): 1.002-1.219] and muscular strength at 6 months after surgery (p = 0.040, OR: 1.155, 95% CI: 1.006-1.326). Only muscle strength at 6 months after surgery influenced the outcome of the force of the knee flexion at 1 year after surgery. In sub-analysis, muscular strength of the knee extension and flexion was greater in the STG group than in the BTB group at 6 months after surgery although there was no difference between muscular strength of the knee extension in the STG group and that in BTB group at 1 year. CONCLUSIONS: Recovery of knee extension strength at a year after ACL reconstruction was significantly associated with preoperative muscular strength and muscle recovery at 6 months. Age and graft type might be related to the muscle strength recovery. Preoperative and early postoperative strength training could improve the recovery of knee extension strength, which would support an earlier return to sports after ACL reconstruction.

Investigation of the control of rotational alignment in the tibial component during total knee arthroplasty.

BACKGROUND: In this study, rotational errors that occur in relation to the tibial component of total knee arthroplasty (TKA) were investigated intraoperatively using a CT-free navigation system and postoperative CT images to confirm the correctness of the rotation. METHODS: Forty patients who underwent TKA using the navigation system were examined. These patients were split evenly into two groups, those whose rotational position was confirmed using a mark made manually on the tibia, and those whose rotation was confirmed using the navigation. All patients underwent postoperative CT scanning and were evaluated using the Knee Society Score. RESULTS: With navigation, a significant difference was found between the rotational positions for which we made a keel hole and those for which the tibial component was inserted unguided. After cementing, the rotational position in the group for which a manual mark was used to confirm the rotation differed significantly from the position for the group for which navigation during cementing was used. Although there were four outliers that had rotational errors over 3° after cementing in the manual mark group, there were no outliers in the navigation group. While there was significant difference in the rotational errors of the tibial component on postoperative CT between two groups, the Knee Society Score did not differ between two groups. CONCLUSION: The exact rotation of a tibial component cannot be maintained by simply creating a keel hole. The use of a manual mark resulted in rotational errors of the tibial component and the creation of the outliers. Therefore, it is suggested that the use of a navigation system can reduce the occurrence of such errors.

Intrawound vancomycin powder increases post-operative wound complications and does not decrease periprosthetic joint infection in primary total and unicompartmental knee arthroplasties.

PURPOSE: A frequent reason for revision surgery after total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is periprosthetic joint infection (PJI). The efficacy of intrawound VP in preventing PJI after primary TKA or UKA is rarely reported. The purpose of this study was to investigate the efficacy and side effects of local high-dose VP application to the joint to prevent PJI in TKA and UKA. METHODS: From 2010 to 2017, 166 consecutive patients that underwent primary TKA or UKA were enrolled. Seventy-five patients (92 knees) did not receive VP (control group), while 90 patients (110 knees, VP group) received VP (intrawound, 1 g) before capsule closure during TKA and UKA. Aseptic wound complications, such as skin erosion, wound dehiscence, and prolonged wound healing, were evaluated within 3 months post-operatively. PJI was assessed within a year post-operatively. RESULTS: Seven patients (7.6%) in the control group and five patients (4.5%) in the VP group had PJI. No significant differences existed in the PJI rates between the groups. Aseptic operative wound complications occurred in 4 patients (4.3%) and 13 patients (11.8%), whereas prolonged operative wound healing occurred in 3 patients (3.3%) and 14 patients (12.7%) of patients in the control and VP group, respectively. Operative wound complications were significantly frequent in the VP group. CONCLUSIONS: Intrawound VP administration does not decrease PJI occurrence in primary TKA and significantly causes aseptic wound complications. The use of intrawound VP for the prevention of PJI after primary TKA and UKA is not recommended. LEVEL OF EVIDENCE: Level II.

Lysophosphatidic acid precursor levels decrease and an arachidonic acid-containing phosphatidylcholine level increases in the dorsal root ganglion of mice after peripheral nerve injury.

In the current study, we aimed to analyze the lipid changes in the dorsal root ganglion (DRG) after sciatic nerve transection (SNT) using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). We found that the arachidonic acid-containing phosphatidylcholine (AA-PC), PC(16:0/20:4) largely increased, while PC(16:0/18:1), PC(18:0/18:1) and phosphatidic acid (PA)(36:2) levels largely decreased in the DRG following nerve injury. Previous studies show that the increase in PC(16:0/20:4) was associated with neuropathic pain and that decrease in PC(16:0/18:1), PC(18:0/18:1), and PA(36:2) were due to producing lysophosphatidic acid (LPA), an initiator for neuropathic pain. These results suggest that the lipid changes in DRG after SNT could be the result of changes for the cause of neuropathic pain. Thus, blocking of LPA could be potential for treatment of neuropathic pain.