A formula for instability-related bone loss: estimating glenoid width and redefining bare spot.

PURPOSE: The aim of the study reveals a new intuitive method for preoperatively assessing defect ratio in glenoid deficiency based on the native glenoid width and the bare spot. METHODS: A linear relationship, i.e. the rh formula, between the native glenoid width (2r) and height (h) was revealed by a cadaver cohort (n = 204). To validate the reliability of the rh formula, 280 3D-CT images of intact glenoids were recruited. To evaluate the accuracy of rh formula in estimating glenoid defect, the 65 anterior-inferior defect models were artificially established based on the 3D-CT images of intact glenoids. Moreover, a clinically common anterior-posterior (AP) method was compared with the rh formula, to verify the technical superiority of rh formula. RESULTS: The regression analysis indicated a linear relationship between the width and height of intact glenoid: 2r = 0.768 × h - 1.222 mm (R2 = 0.820, p < 0.001). An excellent reliability was found between the formula prediction and model width (ICC = 0.911, p = 0.266). An excellent agreement was found between the predicted values and model parameters (glenoid width, ICCrh = 0.967, prh = 0.778; defect ratio, prh = 0.572, ICCrh = 0.997). And, it is of higher accuracy compared to the AP method (glenoid width, ICCAP = 0.933, pAP = 0.001; defect ratio, ICCAP = 0.911, pAP = 0.033). CONCLUSION: Applying the cadaver-based formula on 3D-CT scans accurately predicts native glenoid width and redefines bare spot for preoperatively determining glenoid bone loss.

Severe medial osteoarthritis predicts patient dissatisfaction after proximal fibular osteotomy: a mid- to long-term follow-up study.

PURPOSE: This study aimed to investigate postoperative patient satisfaction at mid- to long-term follow-up after proximal fibular osteotomy and to identify risk factors for patient dissatisfaction. METHODS: This was a retrospective cross-sectional study that included 252 knees from 160 osteoarthritis (OA) patients who underwent proximal fibular osteotomy with a follow-up of four to eight years. Patients were categorized into a satisfied group (satisfaction score ≥ 20) or a dissatisfied group (satisfaction score < 20) based on the New Knee Society Score (New KSS). Patient demographics, preoperative pain visual analogue scale (VAS) score, preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Kellgren-Lawrence (K-L) grade, preoperative hip-knee-ankle (HKA) angle, and preoperative medial proximal tibial angle (MPTA) were compared between the two groups. Multiple logistic regression analysis was used to identify risk factors for patient dissatisfaction. RESULTS: Of the 203 knees, 130 (64.0%) were satisfied with their results. Multiple logistic regression analysis demonstrated that severe medial OA (K-L grade = IV) was an independent risk factor for patient dissatisfaction after proximal fibular osteotomy (OR 8.334, 95% CI 3.815-18.206, P < 0.001). CONCLUSION: Our study confirmed that proximal fibular osteotomy was a simple and effective treatment for medial OA patients, and majority of our patients obtained a higher satisfaction rate within mid- to long-term follow-up after surgery. Severe medial OA, however, was an independent risk factor for dissatisfaction.

Novel ideas for the comprehensive evaluation of varus knee osteoarthritis: radiological measurements of the morphology of the lateral knee joint.

BACKGROUND: The lateral anatomical and morphological characteristics of knees with varus knee osteoarthritis (OA) have not received sufficient attention. This study used several radiological parameters to describe the morphological characteristics of the lateral knee with OA to determine whether there are relationships between varus knee OA and parameters such as lateral plateau widening (LPW), proximal fibula curvature (PFC), and fibula height (FH). METHODS: The study retrospectively analyzed 1072 subjects who underwent standard radiography for diagnosing or evaluating symptomatic knee joint disease. The 163 Kellgren and Lawrence (K-L) grades 0 and I knees were categorized into the no-knee-OA group, and the 909 K-L grades II-IV knees were classified into the knee-OA group. Medial proximal tibial angle, joint line convergence angle, hip-knee-ankle angle, LPW, PFC, and FH were measured. T tests and chi-square tests were used to compare each index between the two groups. Binary logistic regression was performed to examine the correlation between indexes and knee OA occurrence. Ordinal logistic analysis, principal component analysis, and multivariable linear regression analysis were performed to examine the correlations between the three lateral parameters and K-L grades and the degree of varus deformity. RESULTS: LPW and PFC were significantly greater and FH was significantly smaller in the knee-OA group than in the no-knee-OA group. LPW, PFC, and FH were correlated with knee OA occurrence. One principal component, named the comprehensive principal component score of varus deformity, was extracted from the three indexes, and the total variance of the principal component interpretation was 76.60%. Ordinal logistics and multivariable linear regression analysis showed that, after adjusting for age and BMI, LPW and PFC were positively correlated with K-L grading and varus deformity. FH was significantly and negatively correlated with K-L grading and varus deformity (all P < 0.05). CONCLUSIONS: Regular morphological changes take place in the lateral knee with varus OA, including lateral dislocation of the tibial plateau, proximal fibula bending, and upward movement of the fibular head. Changes in LPW, PFC, and FH could enable a more comprehensive assessment of varus knee OA occurrence, severity, and deformity. Level of evidence Retrospective Study Level III.

[Analysis of influencing factors of early pain after arthroscopic rotator cuff repair].

Objective: To evaluate the influencing factors that affect early pain after arthroscopic rotator cuff repair. Methods: A clinical data of 592 patients who met the selection criteria and underwent arthroscopic rotator cuff repair between June 2018 and October 2020 were retrospectively analyzed. There were 239 males and 353 females, with an average age of 58.1 years (range, 32-81 years). Before operation and at 3 days, 6 weeks, and 3 months after operation, the pain degree of patients was evaluated by visual analogue scale (VAS) score; and the patients were divided into no pain or mild pain group and moderate to severe pain group according to the postoperative VAS score. Preoperative and intraoperative related factors were included for univariate analysis, including age, gender, body mass index, preoperative VAS score, history of frozen shoulder, history of hypertension, history of diabetes, history of smoking, affected tendons (supraspinatus, infraspinatus, or subscapularis tendon injury), supraspinatus muscle atrophy, fatty infiltration, operation time, degree of rotator cuff tear, number of anchors, and whether to perform acromioplasty. The influencing factors of postoperative pain were screened; further logistic regression was used to conduct multivariate analysis to screen for risk factors. Results: Moderate to severe pain occurred in 440 patients (74.3%) at 3 days after operation, 382 patients (66.2%) at 6 weeks, and 141 patients (23.8%) at 3 months. Multivariate analysis showed that the women, partial-thickness rotator cuff tear, and acromioplasty were risk factors for pain at 3 days after operation ( P<0.05); the women, combined with fatty infiltration, partial-thickness rotator cuff tear, and acromioplasty were the risk factors at 6 weeks ( P<0.05); and the women, combined with fatty infiltration, and partial-thickness rotator cuff tear were risk factors at 3 months ( P<0.05). Conclusion: Among patients undergoing arthroscopic rotator cuff repair, women, those with smaller rotator cuff tears, combined with fatty infiltration, and acromioplasty have more severe pain within 3 months after operation, and attention should be paid to postoperative analgesia in these patients management, providing an individualized approach to rehabilitation, and closer follow-up.

Prognostic factors for medial open-wedge high tibial osteotomy with spacer implantation in patients with medial compartmental knee osteoarthritis.

BACKGROUND: To identify medial open-wedge high tibial osteotomy (MOWHTO) prognostic factors with wedge-shaped spacer implantation (spacer-type MOWHTO) for varus medial compartment knee osteoarthritis. METHODS: Patients who underwent spacer-type MOWHTO between August 2018 and September 2019 were prospectively enrolled in this study. Patients were divided into effective group and invalid group based on the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) score one year postoperatively. The variables assessed at baseline and one year postoperatively including age, sex, body mass index (BMI), Kellgren-Lawrence (K-L) grade, hip-knee-ankle angle (HKAA), medial proximal tibial angle (MPTA), posterior tibial slope angle (PTSA), Blackburn-Peel index (BPI), duration of symptoms, and WOMAC score were compared. Prognostic factors were analyzed using logistic regression, and the corresponding odds ratios were also calculated. RESULTS: A total of 104 patients were enrolled in the study protocol at one year postoperatively. The WOMAC score decreased from 72.39 ± 12.95 at baseline to 20.06 ± 12.96 at one year postoperatively. Univariate analysis revealed that the significant predictors of the WOMAC score were age > 70 years, BMI > 30 kg/m2, K-L grade IV, and pre-HKAA > 10° (P < 0.1 for all). Multivariable logistic regression analysis revealed that age > 70 (OR = 4.861) and K-L grade IV (OR = 6.590) were significantly associated with the higher WOMAC score at one year postoperatively. CONCLUSIONS: Spacer-type MOWHTO is an effective treatment for osteoarthritis with varus deformity. The prognostic factors for spacer-type MOWHTO are age and K-L grade.

Particle separation by a moving air-liquid interface in a microchannel.

Particle separation is an important topic in microfluidic field and has recently gained significant attention in sample preparations for biological and chemical studies. In this paper, a novel particle separation method was proposed. In this method, the particles were separated by the air-liquid interface in a microchannel. The motion of the air-liquid interface was controlled with a syringe pump. Depending on the air-liquid interface speed, the liquid film thickness and the viscous force on particles were changed and the particles were separated by sizes. We observed the separation of 1.01 µm particles from the larger particles when the air-liquid interface speed was less than 11 µm/s, and the separation of both 1.01 µm and 5.09 µm particles from the larger particles when the interface speed was between 11 µm/s and 120 µm/s. When the speed was higher than 120 µm/s, the drag force of the liquid flow generated by the advancing interface on particles was so strong that the flow removed all particles off from the bottom channel wall and there were no particles left behind the advancing interface.