Cross-cultural adaption, validity, and reliability of the Japanese version of the Central Aspects of Pain in the Knee (CAP-Knee-J) questionnaire in patients with knee pain: a validation study.

BACKGROUND: Knee pain is a prominent concern among older individuals, influenced by the central nervous system. This study aimed to translate the Central Aspects of Pain in the Knee (CAP-Knee) questionnaire into Japanese and investigate its reliability and validity in older Japanese individuals with knee pain. METHODS: Using a forward-backward method, CAP-Knee was translated into Japanese, and data from 110 patients at an orthopedic clinic were analyzed. The Japanese version (CAP-Knee-J) was evaluated regarding pain intensity during walking, central sensitization inventory, and pain catastrophizing scale. Statistical analyses confirmed internal validity and test-retest reliability. Concurrent validity was assessed through a single correlation analysis between CAP-Knee-J and the aforementioned measures. Exploratory factor analysis was employed on each CAP-Knee-J item to examine structural validity. RESULTS: CAP-Knee-J showed good internal consistency (Cronbach's α = 0.86) and excellent test-retest reliability (intraclass correlation coefficient = 0.77). It correlated significantly with pain intensity while walking, central sensitization inventory scores, and pain catastrophizing scale scores. Exploratory factor analysis produced a three-factor model. CONCLUSIONS: CAP-Knee-J is a reliable and valid questionnaire for assessing central pain mechanisms specific to knee pain in older Japanese individuals, with moderate correlations with the CSI and weak with the PCS, thus indicating construct validity. This study supports the development of effective knee pain treatments and prognosis predictions.

Comparison of time courses in postoperative functional outcomes between simultaneous bilateral and unilateral total knee arthroplasty with propensity score matching.

INTRODUCTION/OBJECTIVES: No consensus has been reached on which is better in terms of functional outcomes between simultaneous bilateral and unilateral total knee arthroplasty (TKA). As patient characteristics, such as age, sex, and body mass index, have significant effects on functional outcomes after TKA, these factors should be matched before comparisons are made. This study aimed to compare time courses in functional outcomes between simultaneous bilateral TKA and unilateral TKA after matching the patient characteristics. MATERIALS AND METHODS: In this retrospective study, the clinical records of patients admitted to a hospital were reviewed. Of 425 patients, 43 underwent simultaneous bilateral TKA, whereas 382 underwent unilateral TKA. Propensity score matching was performed for age, sex, and body mass index between simultaneous bilateral and unilateral TKA patients. Therapists measured pain intensity, knee extensor strength, and knee-specific functional outcomes by using the new knee society score, including total score, symptoms, patient satisfaction, patient expectations, and functional activities preoperatively and 3 and 12 months postoperatively. Two-way repeated analysis of variance was performed to compare the time courses in functional outcomes between simultaneous bilateral and unilateral TKA. RESULTS: After propensity score matching, 40 patients each for underwent bilateral TKA and unilateral TKA were selected. Knee extensor strength in simultaneous bilateral TKA patients was significantly lower than that in unilateral TKA patients at 3 months postoperatively (p = 0.04). A significant interaction was observed between the effects of time and group on knee extensor strength (F [1, 78] = 3.338; interaction: p = 0.042; η2 = 0.052). No significant interactions were found among the other variables measured. CONCLUSIONS: Patients who underwent simultaneous bilateral TKA should undergo postoperative rehabilitation focused on alleviating delayed recovery in knee extensor strength during the acute phase.

Contralateral knee pain exacerbation after total knee arthroplasty and its impact on functional activity.

INTRODUCTION: The purposes of the present study were to (1) describe the prevalence of contralateral knee pain exacerbation after total knee arthroplasty (TKA), (2) explore the risk factors for pain exacerbation, and (3) verify the association of contralateral knee pain with future functional activity. MATERIALS AND METHOD: We consecutively recruited outpatients with osteoarthritis of both knees who had primary TKA planned. The contralateral knee pain using a Numerical Rating Scale (NRS) and the functional activities subdomain of the new Knee Society Knee Scoring System (KSS) were assessed preoperatively and at 1, 3, and 6 months postoperatively. Among patients with < 5 NRS points preoperatively, we described the frequency of the contralateral knee pain exacerbation, defined as a ≥ 2-point increase from preoperative pain at each postoperative visit. An exploratory analysis was performed to identify preoperative risk factors for contralateral knee pain exacerbation. A linear mixed model was fit to examine the association of the contralateral knee pain with KSS functional activities at subsequent visits. RESULTS: Among 315 patients, 14.6%, 24.1%, and 27.6% of patients experienced contralateral knee pain exacerbation at 1, 3, and 6 months postoperatively, respectively. The identified preoperative risk factors were low quadriceps strength and higher Kellgren-Lawrence grade on the non-operative knee, along with severe pain on the operative knee. The magnitude of the association between contralateral knee pain and worsening KSS functional activities increased with subsequent visits (p for interaction < 0.001). CONCLUSION: The frequency and impact of pain exacerbation on the contralateral knee increase after TKA and should be carefully evaluated for a prolonged period of time.

U-TEST, a simple decision support tool for the diagnosis of sarcopenia in orthopaedic patients: the Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study (SPSS-OK).

We aimed to develop and validate a new simple decision support tool (U-TEST) for diagnosis of sarcopenia in orthopaedic patients. We created seventeen candidate original questions to detect sarcopenia in orthopaedic patients with sarcopenia through expert opinions and a semi-structured interview. To derive a decision support tool, a logistic regression model with backward elimination was applied to select variables from the seventeen questions, age and underweight (BMI < 18·5 kg/m2). Sarcopenia was defined by Asian Working Group for Sarcopenia 2019 criteria. After assigning a score to each selected variable, the sum of scores was calculated. We evaluated the diagnostic performance of the new tool using a logistic regression model. A bootstrap technique was used for internal validation. Among a total of 1334 orthopaedic patients, sixty-five (4·9 %) patients were diagnosed with sarcopenia. We succeeded in developing a 'U-TEST' with scores ranging from 0 to 11 consisting of values for BMI (Underweight), age (Elderly) and two original questions ('I can't stand up from a chair without supporting myself with my arms' (Strength) and 'I feel that my arms and legs are thinner than they were in the past' (Thin)). The AUC was 0·77 (95 % CI 0·71, 0·83). With the optimal cut-off set at 3 or greater based on Youden's index, the sensitivity and the specificity were 76·1 and 63·6 %, respectively. In orthopaedic patients, our U-TEST scoring with two questions and two simple clinical variables can help to screen for sarcopenia.

Disentangling Associations Between Serum Muscle Biomarkers and Sarcopenia in the Presence of Pain and Inflammation Among Patients With Osteoarthritis: The SPSS-OK Study.

BACKGROUND/OBJECTIVE: Reduction of muscle markers, such as creatine phosphokinase (CK), in rheumatic diseases and its association with reduced muscle mass may be of clinical importance in osteoarthritis (OA). Considering the complexity of secondary sarcopenia, clarifying the association between muscle markers and sarcopenia and disentangling the involvement of OA-related conditions are of clinical importance. We investigated the association between serum muscle biomarkers and sarcopenia among patients with OA, considering the presence of pain and inflammation. METHODS: Overall, 1425 patients with knee and hip OA scheduled for joint replacement surgery were included in a single-center cross-sectional study from Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study. Primary outcome was sarcopenia defined by 2 criteria (the Asian Working Group for Sarcopenia and the European Working Group on Sarcopenia in Older People). Pain and inflammation were measured using the numeric rating scale and serum C-reactive protein (CRP) levels, respectively. Associations between the biomarkers (serum CK, aspartate aminotransferase, alanine aminotransferase) and sarcopenia were examined using logistic regression models. RESULTS: Sarcopenia by the Asian Working Group for Sarcopenia criteria was present in 4.0% of patients. In adjusted analyses, sarcopenia was negatively associated with higher serum CK levels, but not with serum aspartate aminotransferase or alanine aminotransferase levels independent of pain score and serum CRP. Neither pain score nor serum CRP level was associated with sarcopenia. Similar results were found when the European Working Group on Sarcopenia in Older People criteria were used. CONCLUSIONS: Serum CK was associated with sarcopenia, suggesting the potential usefulness for sarcopenia detection regardless of pain or inflammation in OA.

Outcomes of total knee replacement with the use of a NexGen MIS Tibial Component (Mini-keel) : a systematic review.

NexGen MIS Tibial Component (Mini-keel) is a tibial component specially developed for minimally invasive surgery in total knee replacement (TKR), and the size limitations of its design and the modular system could affect tibial fixation strength, however, this has not been precisely evaluated thus far. This study aimed to systematically review the literature describing the outcome following TKR with the use of a Mini-keel. Electronic searches of databases were undertaken in July 2019 by two experienced orthopaedic surgeons according to the PRISMA guidelines for literature describing the outcomes of TKR with the use of a Mini-keel. Quality of studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. The initial search found a total of 623 studies from all the databases. Seven studies met all the inclusion criteria and were eligible for critical appraisal and quality assessment. In total, 2,198 cases were included in the systematic review. Thirty-five revision cases due to aseptic loosening were found from the systematic review. Two studies were negative about using a Mini-keel and three studies were positive about it, while the other two studies did not judge the quality of a Mini-keel. There have been conflicting conclusions among studies for the use of a Mini-keel. There remains a paucity of prospective cohort studies between TKRs with the use of a Mini-keel and those with the use of a conventional implant, which makes it difficult to determine the usefulness and reliability of this implant.

Comparison of recovery of mobility and self-efficacy after total knee arthroplasty based on two different protocols: A prospective cohort study.

Objectives: The purpose of this study was to compare the recovery of mobility and self-efficacy following total knee arthroplasty (TKA) between the 5-day and the 28-day protocol. This prospective cohort study was carried out at two hospitals.Methods: In total, 104 patients who underwent TKA were enrolled. The primary outcomes measured were Life Space Assessment (LSA) for mobility and modified-Gait Efficacy Scale (mGES) for self-efficacy. Knee Society Score (KSS) was used to estimate the functional outcomes. These assessments were performed in all patients preoperatively, and at 1, 3, and 6 months postoperatively. After calculating the propensity score using covariates, such as patient characteristics, LSA, mGES, and KSS at baseline, propensity score-adjusted multivariate analysis of covariance (MANCOVA) was performed.Results: MANCOVA revealed significant differences in LSA and mGES, but not in KSS, between the two protocols. The adjusted means of LSA and mGES in the 28-day protocol were significantly greater than those in the 5-day protocol in all the postoperative assessments.Conclusion: Mobility and self-efficacy were greater following the 28-day protocol than the 5-day protocol after TKA. Our findings suggest that the modified treatment procedure for improving mobility and self-efficacy is necessary to introduce the early discharge protocol in Japan.

Diabetes is a Risk Factor for Restricted Range of Motion and Poor Clinical Outcome After Total Knee Arthroplasty.

BACKGROUND: We investigated the effects of diabetes mellitus on knee range of motion, muscle strength, and functional outcome after total knee arthroplasty. METHODS: A total of 20 patients with type 2 diabetes and 20 patients without diabetes matched for age, body mass index, knee range of motion, and muscle strength at baseline participated in this study. We examined knee range of motion and muscle strength and assessed functional activities using the new Knee Society Score questionnaire for each patient 1 month preoperatively and at 6 and 12 months postoperatively. RESULTS: Patients with diabetes had significantly lower knee flexion and smaller improvements in the new Knee Society Score than patients without diabetes. CONCLUSION: Our results suggest that clinicians should treat and monitor patients with diabetes closely to prevent restricted knee range of motion and poorer functional recovery after total knee arthroplasty.

Comparison of Acute-Phase Pain Intensity, Pain Trajectory, and the Number of Analgesics Administered between Total and Unicompartmental Knee Arthroplasties.

We aimed to compare the variables of pain intensity, pain trajectory, and the number of analgesics administered during the acute phase between total and unicompartmental knee arthroplasties. This prospective cohort study recruited 445 patients who planned to undergo knee arthroplasty. Pain intensity was evaluated during hospitalization, and 1 month postoperatively using a numerical rating scale. Pain trajectory (slope and intercept) was calculated using pain intensity data from postoperative days 1 to 4. The number of analgesics administered for worsening pain was monitored during hospitalization. Multiple linear regression analysis with adjustment for potential confounders was conducted to investigate the impact of surgery type on pain variables. Data for 208 and 189 patients who had undergone total and unicompartmental knee arthroplasties, respectively, were included in this study. Pain intensity and pain trajectory were similar between the two surgeries. The number of analgesics administered on postoperative day 3 (p = 0.01) and day 4 (p = 0.03), as well as total number (p = 0.01), were lower for unicompartmental knee arthroplasty than for total knee arthroplasty. Multiple linear regression analysis showed that the type of surgery affected the total number of analgesics administered (ß = - 1.24, p < 0.01, 95% confidence interval: -1.80 to -0.62). This study suggests that pain characteristics observed during the acute phase differ between total and unicompartmental knee arthroplasties. Postoperative pain should be managed, and rehabilitation should be provided at similar levels after the second postoperative day in total and unicompartmental knee arthroplasty patients.

Association between phase angle and functional disability among patients with lumbar spinal stenosis: The SPSS-OK study.

BACKGROUND: Whether the lower phase angle associated with worse physical function is a result of pain and muscle weakness in patients with lumbar spinal stenosis (LSS) is unclear. OBJECTIVE: To evaluate the association between phase angle and back pain-specific disabilities in patients with LSS. METHODS: In this single-center, cross-sectional study, 491 participants with LSS were enrolled. The phase angle and back pain-specific disability were measured using bioelectrical impedance analysis and the Oswestry Disability Index, respectively. General linear models were used to examine associations between phase angle and the Oswestry Disability Index with or without adjustment for age, sex, low back and lower limb pain, numbness in the lower extremities, total fat mass, and lower limb muscle mass. RESULTS: The mean (SD) phase angle was 4.4∘ (1.0∘), and the mean Oswestry Disability Index was 36.1 (14.1) points. Greater phase angles were associated with less Oswestry Disability Index points (p= 0.037) independent of fat mass, low back pain, and hip or lower limb pain. CONCLUSIONS: A lower phase angle was associated with worse functional disability. Low phase angle may be an indicator of functional impairment due to low back pain associated with LSS.

Soft tissue balance measurement in minimal incision surgery compared to conventional total knee arthroplasty.

PURPOSES: Minimal incision surgery (MIS) total knee arthroplasty (TKA) is widely promoted as a possible improvement over conventional TKA, and accurate implantations have recently been reported using navigation systems. However, soft tissue balance during MIS-TKA remains challenging. Therefore, in this report, joint gap (component gap) and ligament balance (varus angle) were assessed during MIS-TKA using a tensor, which enables soft tissue balance assessment with a reduced patellofemoral joint and femoral component in place. METHODS: Results were compared to those of conventional TKA. Posterior stabilized TKA were performed in 50 knees (25 knees: MIS-TKA using quadriceps-sparing approach; 25 knees: conventional TKA using medial parapatellar approach) with varus osteoarthritis. Component gap and varus angle were measured using the tensor with a reduced patellofemoral joint at 0, 10, 45, 90, and 135°. RESULTS: Whereas the component gap in MIS-TKA was significantly larger through the entire arc of flexion compared with conventional TKA, the pattern of joint looseness showed no difference between the two procedures. The varus angle in MIS-TKA was significantly larger than that in conventional TKA at 0, 90, and 135° of knee flexion. CONCLUSIONS: MIS-TKA may lead to ligament imbalance due to the difficulties induced by a limited working space. Understanding this pattern allows surgeons to be able to adjust the soft tissue balance more accurately and thereby expect a better post-operative outcome even in MIS-TKA.

Total knee arthroplasty combined with medial patellofemoral ligament reconstruction for osteoarthritic knee with preoperative valgus deformity and chronic patellar dislocation.

We report a challenging case of a 44-year-old woman who had osteoarthritis in the lateral compartment of her right knee with severe valgus deformity and chronic lateral patellar dislocation. Total knee arthroplasty was performed for the knee. However, persistent patellar dislocation remained during the surgery; and therefore, medial patellofemoral ligament (MPFL) reconstruction was additionally performed at the time of the surgery. Stable patellar tracking was obtained after the MFPL reconstruction; and during the 2-year follow-up, her knee functioned well, and no recurrent patellar dislocation was observed. This clinical case indicates the usefulness of MPFL reconstruction for obtaining stable patellar tracking during total knee arthroplasty when a tendency for lateral patellar dislocation remains.

The associations of phase angle with the structural severity and quadriceps strength among patients with hip osteoarthritis: the SPSS-OK study.

INTRODUCTION/OBJECTIVES: This study examined whether phase angle (PhA) is associated with hip osteoarthritis (HOA) severity and quadriceps strength in patients with HOA. METHOD: A series of 549 patients with HOA, obtained from the Screening for People Suffering Sarcopenia in the Orthopedic cohort of Kobe study, were analyzed. PhA and quadriceps strength were measured using bioelectrical impedance analysis and a handheld dynamometer, respectively. The HOA severity was graded using the Kellgren-Lawrence radiographic scale. We estimated (1) mean differences in PhA by differences in HOA severity and (2) mean differences in quadriceps strength by differences in PhA using general linear models. RESULTS: The patients' mean age was 64.9 years, and 85% were women. A decreasing trend of PhA associated with increasing HOA severity was observed (P for trend < 0.001). PhA was statistically associated with a decrease in HOA grade 4 compared with that associated with HOA grade 1 (mean difference, - 0.40°; 95% confidence interval (CI), - 0.51° to - 0.30°). PhA per leg was associated with greater quadriceps strength per leg independent of age, sex, leg muscle mass, and HOA severity (mean difference per 1° increase, 3.80 Nm; 95% CI, 0.93 to 6.66). There was insufficient evidence of any difference in the association between PhA and quadriceps strength by HOA severity and sex (P for interaction = 0.07 and 0.06, respectively). CONCLUSIONS: PhA gradually decreased with increasing HOA severity, especially in patients with end-stage HOA. Paying close attention to PhA might provide a key to increasing quadriceps strength, regardless of HOA severity. Key Points • PhA gradually decreased with progression of HOA, particularly in patients with end-stage HOA. • PhA was positively associated with quadriceps strength, regardless of HOA severity. • PhA could be one of the indicators of quadriceps strength in patients with HOA.

Knee Flexion Angle Following Total Knee Arthroplasty Relates to a Preoperative Range of Motion of the Hip.

BACKGROUND: Many factors have been reported to affect postoperative range of knee flexion after total knee arthroplasty (TKA); however, no study has reported the impact of preoperative range of motion of the hip to the postoperative flexion angle of the knee thus far. METHODS: Of 38 consecutive patients who underwent posterior-stabilized TKA, we assessed 21 patients after excluding 17 patients who met exclusion criteria. The range of motion of the knee and the hip, age, body-mass index, serum albumin level, HbA1c, Kellgren-Lawrence grade, knee extension strength and radiological femorotibial angle as well as postoperative knee flexion angle at three months were evaluated. The preoperative data and the knee flexion angle at three months after TKA were compared using Spearman's rank correlation coefficient. RESULTS: Knee flexion angle at three months after TKA was positively correlated with preoperative flexion (ρ = 0.616, p = 0.007) and external rotation angle (ρ = 0.576, p = 0.012) of the hip as well as preoperative knee flexion angle (ρ = 0.797, p = 0.001). There were no correlations between postoperative knee flexion angle and other preoperative data. CONCLUSIONS: Patients with restricted flexion and/or external rotation of the hip may have contractures of Gluteus maximus, Gluteus medius and Tensor fasciae latae, which can cause hypertension of iliotibial tract. It may cause decreased internal rotation of the tibia when the knee is flexed, which affects postoperative knee flexion angle, thus limited flexion and/or external rotation of the hip might restrict knee flexion angle following TKA.

Association of objectively measured physical activity with combined bilateral knee and low-back pain in older adults with knee osteoarthritis: A cross-sectional study.

OBJECTIVE: Knee pain (KP) and low-back pain (LBP) are common sites of pain and major public health issues among older adults. We investigated the combined association of bilateral KP and LBP with objectively measured physical activity (PA) among adults with knee osteoarthritis (OA). METHODS: We recruited 150 knee OA adults and measured steps and PA intensity, including sedentary behavior (SB), low PA (LPA), and moderate-to-vigorous PA, using an accelerometer. KP and LBP were measured using a numerical rating scale. They were classified into 4 groups based on the presence of KP and LBP: with the only unilateral KP (UKP), with the combined UKP and LBP (UKP and LBP), with the bilateral KP (BKP), and with the combined bilateral KP and LBP (BKP and LBP). One-way analysis of covariance was performed to compare physical activity variables (intensity or steps) between the four groups. RESULTS: Overall, 126 patients were enrolled. The prevalence of UKP, BKP, UKP and LBP, and BKP and LBP were 29.4%, 23.8%, 18.3%, and 28.6%. The proportion of SB was higher in the BKP and LBP group than in the other groups (F = 6.51, p < 0.01). The proportion of LPA was lower in the BKP and LBP group than in the other groups (F = 6.21, p < 0.01). CONCLUSIONS: The proportions of SB and LPA were significantly worse in knee OA adults with BKP and LBP than in those with UKP. Our findings may be a basis for considering knee OA adults for improving PA.

A Double-Blind, Placebo-Controlled Study of Ultrasound-Guided Pulsed Radiofrequency Treatment of the Saphenous Nerve for Refractory Osteoarthritis-Associated Knee Pain.

BACKGROUND: While the efficacy of pulsed radiofrequency (PRF) for shoulder pain has been demonstrated, its efficacy on the saphenous nerves for knee osteoarthritis (OA)-associated pain has only been reported in observational studies. OBJECTIVES: The aim of this study was to compare saphenous nerve PRF to placebo for knee OA-associated pain. STUDY DESIGN: Patients, practitioners, and outcome assessor-blinded randomized placebo-controlled trial. SETTING: Pain management clinics at 2 hospitals in Japan. METHODS: Patients were randomly allocated to the PRF (n = 37) or placebo group (n = 33). Patients aged 40-85 years with refractory anteromedial knee pain. PRF in the saphenous nerve under ultrasound guidance. The placebo group underwent the same procedure, but with motor stimulation. The primary endpoint was the average pain intensity measured using the visual analog scale (VAS) at the 12-week post-treatment visit; secondary outcomes included the average VAS at 1 and 4 weeks, and pain intensities at rest, in flexion, at standing, and at walking. Other secondary outcomes were knee pain, symptoms, activities of daily living, knee-related quality of life, mobility, range of motion, and adverse events. RESULTS: In the PRF group, the mean VAS score was 52.41 ± 26.17 at 12 weeks, while in the sham group, the mean VAS score was 63.06 ± 27.12 (P < 0.05). There were no significant differences between the groups in any of the secondary outcomes. LIMITATIONS: Patients with comorbidities were excluded from this study. The follow-up time was limited to 12 weeks. CONCLUSIONS: Ultrasound-guided saphenous nerve PRF proved to be effective for at least 12 weeks in patients with knee OA and showed no adverse events.

Structural severity, phase angle, and quadriceps strength among patients with knee osteoarthritis: the SPSS-OK study.

INTRODUCTION/OBJECTIVES: The associations between severity of knee osteoarthritis (KOA) and phase angle (PhA) and between PhA and quadriceps strength in patients with KOA are unclear. This study examined (1) whether the structural severity of KOA affects PhA and (2) whether PhA affects quadriceps strength in patients with KOA. METHOD: Data of 1093 patients with KOA, obtained from Screening for People Suffering Sarcopenia in the Orthopedic cohort of Kobe study, were analyzed. PhA was determined by bioimpedance. Quadriceps strength was measured using a handheld dynamometer. Structural severity of KOA was determined using Kellgren-Lawrence radiographic grading scale. A series of general linear models were fitted to estimate the magnitude of differences in PhA by differences in KOA severity and quadriceps strength by differences in PhA. RESULTS: The mean age of the patients was 72.8 years, and 78% were women. Increasing KOA severity was associated with decreasing PhA, especially in men. In women, only grade 4 KOA was associated with a decrease in PhA (P for interaction = 0.048). PhA per leg was positively associated with quadriceps strength per leg, independent of age, sex, leg muscle mass, pain, and KOA severity (mean difference per 1° increase = 7.54 Nm, 95% confidence interval = 5.51-9.57 Nm). The association between PhA and quadriceps strength differed neither by sex nor by KOA severity (P for interaction = 0.133 and 0.185, respectively). CONCLUSIONS: PhA decreased with increasing KOA severity, and increasing PhA was associated with increasing quadriceps strength. Clinicians should, therefore, evaluate PhA to assess quadriceps strength in patients with KOA. Key Points • PhA gradually decreased with increasing severity of KOA, especially in men. • Increasing PhA was associated with increasing quadriceps strength. • Clinicians should focus on increasing muscle mass and PhA.

Implications of evaluating leg muscle mass and fat mass separately for quadriceps strength in knee osteoarthritis: the SPSS-OK study.

OBJECTIVE: To examine the influence of obesity on quadriceps strength by separately analyzing body mass index (BMI) as fat mass and leg muscle mass in patients with knee osteoarthritis (KOA). METHODS: The Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe (SPSS-OK) study was a single-center cross-sectional study that recruited 906 patients with KOA. Fat mass and leg muscle mass were measured by bio-impedance. Isometric knee extension torque (Nm) was measured as quadriceps strength. A series of general linear models were fitted to estimate the continuous associations of BMI and fat mass with quadriceps strength, with adjustment of confounders. In the fitted models, both BMI and fat mass were treated as restricted cubic spline functions. RESULTS: A continuous, non-linear relationship between BMI and quadriceps strength was found (P = 0.008 for non-linearity). In patients with a BMI of 16-25 kg/m2, increasing quadriceps strength was observed. However, in patients with a BMI of 25-40 kg/m2, quadriceps strength seemed similar. Additionally, an inverted U-shaped relationship between fat mass and quadriceps strength was demonstrated (P = 0.04 for non-linearity). In those with a fat mass of 10-20 kg, increasing quadriceps strength was seen. However, in patients with a fat mass of 20-30 kg, quadriceps strength showed a decreasing trend. Independent of fat mass, leg muscle mass was linearly associated with greater quadriceps strength. CONCLUSION: Our study suggests that there are independent associations between the leg muscle mass, fat mass, and quadriceps strength. It is difficult to easily predict quadriceps strength using only BMI. KEY POINTS: • An increase in body mass index (BMI) up to 25 kg/m2was associated with increasing quadriceps strength. • Quadriceps strength remained almost unchanged among patients with a BMI of > 25 kg/m2. • The association between fat mass and quadriceps strength had an inverted U-shaped relationship, suggesting the importance of the separate assessment of fat mass and muscle mass in patients with knee osteoarthritis, especially those who are overweight or obese.

Importance of knee flexion range of motion during the acute phase after total knee arthroplasty.

BACKGROUND: We investigate the association with knee flexion range of motion (ROM) during the acute phases and that at 12 months after total knee arthroplasty (TKA). We also clarified the cut-off ROM during the acute phases in predicting the goal of knee flexion ROM at 12 months. METHODS: In this retrospective study, 193 patients with knee osteoarthritis (female:144 patients, age:73.2 ± 7.7 years) who underwent unilateral TKA at an orthopedic clinic were recruited. They underwent assessments of knee flexion ROM at 5 days, 1 month, and 12 months after TKA. The goal of knee flexion ROM at 12 months after TKA was set at 120°. Single and logistic-regression analyses were performed with the dependent variables including the outcome of the goal of knee flexion ROM at 12 months, and the independent variables included knee flexion ROM at 5 days and 1 month, separately. We calculated the cut-off ROM at 5 days and 1 month for predicting the goal of knee flexion ROM at 12 months with receiver operating curve analysis. RESULTS: Knee flexion ROM at 5 days and 1 month were significantly associated with the goal of that at 12 months (p < 0.01). The cut-off ROM were 85° at 5 days and 105° at 1 month separately. CONCLUSIONS: Our results suggest the importance of early improvement in knee flexion ROM after TKA, and that at 1 month postoperatively indicates the likelihood of achievement of the goal of knee flexion ROM at 12 months after TKA.

Effect of self-calf massage on the prevention of deep vein thrombosis after total knee arthroplasty: A randomized clinical trial.

OBJECTIVE: Deep vein thrombosis (DVT) is a severe complication after total knee arthroplasty (TKA). Performing self-calf massage may decrease the incidence of DVT. The purpose of this study was to investigate whether self-calf massage is effective for preventing DVT after TKA. METHOD: In all, 165 patients participated in the present study. Patients were randomized to one of two groups: the self-calf massage group or the control group. In the control group, patients started regular physical therapy. In the self-calf massage group, in addition to regular physical therapy, patients were instructed to massage their calf muscles 30 times from the distal to proximal side. This procedure was repeated three times and was completed in 2 mins during the 2 days following TKA. All patients were evaluated for DVT on postoperative day 3 using lower limb vein ultrasonography. RESULTS: The incidence of DVT was significantly lower in the self-calf massage group than in the control group. Self-calf massage was associated with a lower incidence of DVT, whereas age and female sex were risk factors for DVT. CONCLUSION: This study showed that the self-calf massage may be beneficial for the prevention of DVT after TKA.