Role of tear size and tendon degeneration for development of pain in rat models of rotator cuff tear.

BACKGROUND: Rotator cuff tear (RCT) is a frequent etiology of shoulder pain and disability; however, the triggers for the onset and aggravation of pain remain obscure. In this study, we established novel rat RCT models to examine the impact of tear size and tendon degeneration on pain. METHODS: Fifty-five adult male Sprague-Dawley rats were allocated into 4 study groups: large tear (L group, n = 10), small tear (S group, n = 15), small tear with scratching (S+ group n = 15), and sham surgery (Sham group, n = 15). Pain-related behaviors were evaluated by weight distribution of forelimbs during a 5-minute free gait using a dynamic weight-bearing apparatus at 2, 4, 6, and 8 weeks. Calcitonin gene-related peptide (CGRP) expressions in ipsilateral dorsal root ganglion (DRG) neurons of C4, C5, and C6 were evaluated at 4 and 8 weeks. The area of scar tissues around the torn tendon, infiltration of inflammatory cells, and severity of tendon degeneration (modified Bonar score) were histologically assessed at 4 and 8 weeks. Additionally, enzyme-linked immunosorbent assay (ELISA) was conducted to evaluate the levels of cyclooxygenase-2 (COX-2) and nerve growth factor (NGF) expression in torn tendons and surrounding tissues at 4 weeks. RESULTS: The weight distribution ratio (ipsilateral and contralateral side) was significantly decreased in the L and S+ group compared with its baseline and Sham group (P < .05), but the S group showed no significant difference compared with the Sham. The ratio of CGRP-immunoreactive neurons in the DRGs was significantly higher in the L and S+ groups than in the S and Sham groups. The histologic assessment indicated that scar tissue formation was more extensive in the L group than in the S and S+ groups. Still, there was no significant difference between the S and S+ groups. The modified Bonar score was considerably higher in the S+ group than in the S group. Furthermore, ELISA analysis demonstrated no significant disparity in COX-2 levels between the groups; however, NGF levels were substantially higher in the S+ group than in the S and Sham groups. CONCLUSION: The present study provides compelling evidence that large RCT is strongly associated with heightened pain severity in a rat model. Nevertheless, even a small tear can significantly aggravate pain when the torn tendon is degenerated. CGRP upregulation driven by peripheral NGF possibly played a pivotal role in the genesis and exacerbation of pain in small RCT.

Precision of the ultrasonography-integrated tibial extramedullary guide for total knee arthroplasty.

PURPOSE: Precise determination of the tibial mechanical axis in total knee arthroplasty (TKA) requires intraoperative identification of the talus center. We present the ultrasonography-integrated tibial extramedullary guide (USG) that enables real-time visualization of the talus. This study assesses the precision of USG compared to computer-assisted surgery (CAS) and validates the efficacy of USG. METHODS: We evaluated 58 patients (62 knees) who underwent primary TKA retrospectively, categorizing them into USG and CAS groups (31 each). We statistically analyzed demographic data, the preoperative alignment of the tibial plateau to the mechanical axis, the postoperative alignment of the tibial component to planned alignment on 3D-CT, pain visual analog scale, and WOMAC scores. Additionally, the frequency of postoperative outlier from planned alignment over 2° was statistically compared. RESULTS: No significant differences were observed in the preoperative data between the groups. The accuracy (mean deviation from the planned alignment) in both groups was not statistically different. However, in terms of the precision of coronal alignment, the USG group exhibited lower variance than the CAS group in the F-test (F value = 2.76, p = 0.023). Moreover, there were no postoperative deviations beyond 2 degrees in the USG group, in contrast to a 20% outlier frequency in the CAS group (p = 0.024). Concerning the precision of sagittal alignment (variance and deviations over 2°), no statistical differences were identified. CONCLUSION: The USG demonstrated higher precision in the tibial coronal plane than CAS in coronal alignment. Direct identification of the individual talus may enhance precision.

Association between infrapatellar fat pad ultrasound elasticity and anterior knee pain in patients with knee osteoarthritis.

This study investigates whether infrapatellar fat pad (IPFP) elasticity is associated with anterior knee pain in patients with knee osteoarthritis (KOA). The IPFP elasticity of 97 patients with KOA (Kellgren and Lawrence [KL] grades of the femorotibial and patellofemoral joints ≥ 2 and ≤ 2, respectively), aged 46-86 years, was evaluated via shear wave speed using ultrasound elastography. The patients were divided into two groups according to the presence or absence of anterior knee pain. Univariate analyses were used to compare patient age, sex, femorotibial KL grade, magnetic resonance imaging findings (Hoffa, effusion synovitis, bone marrow lesion scores, and IPFP size), and IPFP elasticity between the groups. Multivariate logistic regression analyses were subsequently performed using selected explanatory variables. IPFP elasticity was found to be associated with anterior knee pain in the univariate (p = 0.007) and multivariate (odds ratio: 61.12, 95% CI 1.95-1920.66; p = 0.019) analyses. Anterior knee pain is strongly associated with stiffer IPFPs regardless of the femorotibial KL grade, suggesting that ultrasound elastography is useful for the diagnosis of painful IPFP in patients with KOA.

Association Between Power Doppler Ultrasound Signals and Chronic Pain After Total Knee Arthroplasty: A Cross-Sectional Explorative Study.

Purpose: Some patients experience chronic postsurgical pain (CPSP) after total knee arthroplasty (TKA) despite the absence of clinical or radiographic abnormalities. Postoperative synovitis as a cause of CPSP after TKA has received limited research attention. This study aimed to investigate the relationship between synovitis after TKA and CPSP. Patients and Methods: A total of 111 knees of 85 patients, with at least 1-year post-TKA follow-up, were assessed retrospectively and cross-sectionally. Power Doppler (PD) ultrasonography was used to detect the synovial hypervascularity associated with synovitis. The knee joint was divided into 15 areas, and PD signals were graded semi-quantitatively (0-3) in each area, the sum of which was defined as the total PD score. Clinical information regarding CPSP, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscales, was recorded. The relationship between pain and PD ultrasonography findings was accessed. Patients were divided into two groups (CPSP+ and CPSP- groups) based on pain severity. Clinical information, including PD ultrasonography findings and other possible causes, was compared between the groups. Results: The WOMAC pain subscale was significantly correlated with the total PD score and maximum PD grade (r=0.3977, p<0.0001; r=0.2797, p=0.0029; respectively). The CPSP+ group had a significantly higher maximum PD grade and total PD score than the CPSP- group (median [interquartile range]: 2 [1, 2] vs 1 [1, 2], p=0.0001; 6 [2, 11] vs 2 [1, 4], p=0.0002; respectively). Multiple and logistic regression analyses showed that the total PD score was an independent factor for the WOMAC pain subscale (ß=0.3822, 95% confidence interval [CI]=0.1460, 0.6184, p=0.00176) and CPSP (odds ratio=1.19, 95% CI=1.01, 1.41, p=0.0424). Conclusion: This study indicated a possible association between the total PD score and chronic pain after TKA; however, further studies are needed to corroborate these findings.

Associations of serum leptin levels with intra-articular inflammatory cytokine levels in acute arthritic and nonarthritic knees of mice.

BACKGROUND: The roles of serum leptin in knee joint inflammation are unclear. The objective of this study was to identify any associations of serum leptin level with intra-articular inflammatory cytokine levels in acute arthritic and nonarthritic knees of mice. METHODS: Acute arthritis was induced by intra-articular injection of 2% carrageenan. Three groups (leptin-deficient ob/ob, wild-type (WT) and high-fat diet (HFD)-fed WT) were made. Serum leptin and inflammatory cytokines in the infrapatellar fat pad and synovium were measured before and 24 hr after injection. Affected knee joints were excised for histology 24 hr after injection. RESULTS: The HFD-WT group had significantly higher serum leptin than the ob/ob and WT groups before and after carrageenan injection. The HFD-WT group had significantly higher IL-1? and IL-6 in the infrapatellar fat pad and synovium than ob/ob and WT before injection but significantly lower IL-1?, IL-6 and TNF-? than the ob/ob group at 24 hr. CONCLUSIONS: Hyperleptinemia induced by a HFD is involved in low-grade intra-articular inflammation in nonarthritic knee joints. In contrast, leptin deficiency causes excessive intra-articular inflammation in carrageenan-induced acute arthritis. Leptin alleviates acute arthritis, while chronic hyperleptinemia is involved in low-grade inflammation in normal knee joints. J. Med. Invest. 70 : 54-59, February, 2023.

The effect of postmenopausal osteoporosis on subchondral bone pathology in a rat model of knee osteoarthritis.

This study aimed to investigate the additional effect of ovariectomy-induced osteoporosis (OP) on the pathology of knee osteoarthritis (OA) in a rat meniscectomized model, particularly focusing on subchondral bone changes and pain behaviour. Rats were divided into four groups, sham, OP, OA, OP plus OA, and assessed for histology, osteoclast activity, subchondral bone microstructure, and pain-related behaviour. Rats with OP plus OA had significantly increased calcified cartilage and subchondral bone damage scores, increased densities of subchondral osteoclasts in the weight-bearing area, and more porous subchondral trabecular bone compared with rats with OA. Loss of tidemark integrity was observed most frequently in rats with OP plus OA. The density of subchondral osteoclasts correlated with the calcified cartilage and subchondral bone damage score in rats with OA (OA and OP plus OA). No significant differences in the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) expression ratio in subchondral bone and pain-related behavioural tests were observed between rats with OA and rats with OP plus OA. In rats with OA, coexisting OP potentially aggravated OA pathology mainly in calcified cartilage and subchondral trabecular bone by increasing subchondral osteoclast activity.

Arthroscopic labral repair combined with less invasive open-shelf acetabuloplasty for patients with developmental dysplasia of the hip.

Hip arthroscopy has become widely used for intra-articular lesions, such as labral tears and femoral acetabular impingement. However, its use in patients with developmental dysplasia of the hip (DDH) has been controversial and has historically demonstrated mixed results, as acetabular dysplasia may cause instability due to insufficient bony coverage of the femoral head, thus causing excessive stress on the repaired labrum and cartilage. We devised a combined hip arthroscopic labral repair and a less invasive open-shelf procedure using a small skin incision as an anterolateral portal in hip arthroscopy. This novel procedure may improve the stability of the repaired labrum with a bony covering in a minimally invasive manner. Moreover, the shelf procedure can be performed under direct vision in a comparatively safe and precise manner. In total, 13 hips with DDH underwent the procedure for labral tears. All patients were females, with a mean age of 30 years. The mean follow-up period was 33 months. The mean Harris hip score improved from 74.2 to 93.6, and Oxford Hip score improved from 32.4 to 19.3. According to the Tönnis classification, the grade of arthritis preoperatively was grade 0 for nine hips and grade I for four hips. No radiographic progression of osteoarthritis was observed. It is possible that this novel procedure could be an effective treatment for labral tears with DDH and may prevent the early onset of secondary osteoarthritis. In this technical tip, we describe hip arthroscopic labral repair combined with a less invasive open-shelf acetabuloplasty in further detail.

A Novel Rat Model to Study Postsurgical Pain After Joint Replacement Surgery.

Purpose: The mechanisms underlying chronic postsurgical pain after joint replacement (JR) are complex, and it has been suggested that chronic postsurgical pain can develop as a result of inadequate acute pain management. Few studies have addressed acute pain after JR using specific animal models. This study aimed to develop a novel JR model focused on postsurgical pain assessment and the time course of pain recovery. Materials and Methods: Rats were allocated to the following three groups: sham (joint exposure), joint destruction (JD; resection of the femoral head), and JR (femoral head replacement using an originally developed implant). The time course of postsurgical pain behavior was measured using a dynamic weight-bearing apparatus, along with radiological assessments. The expression of calcitonin gene-related peptide-immunoreactive (CGRP-IR) neurons in the dorsal root ganglion (DRG) was evaluated by immunohistochemistry on days 28 and 42. Results: The ratio of weight-bearing distribution in the JR group gradually recovered from day 14 and reached the same level as that in the sham group on day 42, which was significantly greater than that in the JD group after day 7 (p<0.05). Radiologically, no significant issues were found, except for transient central migration of the implant in the JR group. The percentage of CGRP-IR DRG neurons in the JR group was significantly lower than that in the JD group on day 28 (mean, 37.4 vs 58.1%, p<0.05) and day 42 (mean, 32.3 vs 50.0%, p<0.05). Conclusion: Our novel JR model presented acute postsurgical pain behavior that was successfully recovered to the baseline level at day 42 after surgery. Difference of the pain manifestation between the JR and JD groups could be supported by the expression of CGRP-IR in DRG neurons. This model is the first step toward understanding detailed mechanisms of post-JR pain.

Increased Calcitonin Gene-Related Peptide Expression in DRG and Nerve Fibers Proliferation Caused by Nonunion Fracture in Rats.

PURPOSE: Nonunion bone fracture can be a cause of persistent pain, but the pathophysiology remains largely unknown. The objective of this study was to identify how nonunion affect persistent pain after fracture. Specifically, we evaluated the association of neuropeptide change in dorsal root ganglia (DRG) and nerve proliferation at fracture sites with pain. METHODS: Rat union and nonunion fracture models were created. A piece of latex glove was placed at the fracture site to create a nonunion model. At 6 weeks after surgery, bone healing was assessed using radiography. In addition, the presence of calcitonin gene-related peptide-immunoreactive (CGRP-IR) DRG at the level of L3 and anti-growth associated protein 43-immunoreactive (GAP43-IR) nerve fibers in the scar tissue between the bone fragments were evaluated. Pain-related behavior was assessed using forced treadmill running. RESULTS: In radiological images at 6 weeks after surgery, callus formation was formed continuously between bone fragments in the union models. On the one hand, a clear gap was detected between fragments in nonunion models. The percentage of CGRP-IR DRG cells and the density of GAP43-IR nerve fibers in the scar tissue between the bone fragments in nonunion models was significantly higher than that in union models (p < 0.05). An increase in inflammatory cell infiltrate was observed in scar tissues in the nonunion models. During forced treadmill running, rats in the union model could run significantly longer than those in the nonunion models. CONCLUSION: Increased CGRP expression in DRG cells and abnormal nerve proliferation secondary to prolonged inflammation could lead to persistent pain after bone fracture. In clinical practice, early achievement of bone union may minimize the development of persistent pain after fractures.

A novel mice model of acute flares in osteoarthritis elicited by intra-articular injection of cultured mast cells.

PURPOSE: Mast cells are multifunctional in osteoarthritis (OA), and infiltration of activated mast cells likely contributes to disease severity and progression. However, the detailed mechanisms of action are unclear. The purpose of this study was to elucidate the role of mast cell infiltration in OA at histological level using a new mice model and to investigate pharmacological inhibitory effects of existing mast cell stabilizers in this model. METHODS: Mice were injected intra-articularly with monosodium iodoacetate (MIA 0.5 mg) or PBS on day 0, and PBS, with or without mast cells (MC: 1 × 106 cells) on day 14. They were divided into four groups: OA flare (MIA + MC), OA (MIA + PBS), MC non-OA (PBS + MC), and PBS non-OA (PBS + PBS). In OA flare, the MC stabilizer drug (tranilast: 400 mg/kg/day) or PBS was administered intraperitoneally from days 15 to 21. RESULTS: Histologically, modified Mankin score of the OA flare was significantly higher than that of OA (7.0 [1.8] vs. 3.3 [1.3], P < 0.05), and a larger number of mast cells was observed in OA flare than in OA (34.5 [6.3]/mm2 vs. 27.2 [2.3]/mm2, P < 0.05) on day 22. OA flare also showed acute exacerbation of pain and increased gene expression of pro-inflammatory cytokines and aggrecanase compared with OA. Administration of tranilast to OA flare-up provoked significant improvements in term of histological changes, pain, and gene expression at day 22. CONCLUSION: Our novel model possibly mimics OA flare conditions, which may open a new strategy of disease-modifying treatment for OA, focused on controlling the multiple functions of mast cells.

Comparison of Predisposing Factors Between Pain on Walking and Pain at Rest in Patients with Knee Osteoarthritis.

PURPOSE: Patients with knee osteoarthritis (OA) complain of various types of pain, divided into two main categories: pain on movement and pain at rest. A thorough understanding of pain is essential for managing knee OA; however, few studies have investigated the mechanisms underlying the two different types of pain. This study aimed to clarify the predisposing factors for pain in patients with knee OA with a focus on differences between pain on walking and pain at rest. PATIENTS AND METHODS: This study involved 93 patients, aged 44-90 years, with knee OA, including 74 women. We assessed demographic variables (sex, age, body mass index [BMI], side), visual analogue scale (VAS) score on walking, VAS score at rest, Kellgren and Lawrence (KL) grade on radiograph, synovitis score and bone marrow lesion (BML) score on magnetic resonance imaging, and pressure pain threshold (PPT), and used univariate and multiple regression analyses to investigate factors predisposing patients to pain at rest or pain on walking. RESULTS: In the univariate analyses, we found significant correlations between VAS score on walking and BMI (r=0.31, p<0.01), KL grade (r=0.40, p<0.01), synovitis score (r=0.26, p=0.01), and BML score (r=0.36, p<0.01), whereas VAS score at rest correlated with PPT (r=-0.23, p=0.02) and BMI (r= 0.26, p=0.01). Multiple regression analysis showed that significant explanatory factors for VAS score on walking were BMI (ß=0.22, p=0.03) and KL grade (ß=0.27, p=0.03). By contrast, PPT was the only significant explanatory factor for VAS score at rest (ß=-0.27, p=0.01). CONCLUSION: Predisposing factors were significantly different between pain on walking and pain at rest, indicating that different pain mechanisms exist in the two types of pain. Pain on walking was more strongly associated with mechanical and structural factors, while pain at rest was associated with mechanical hyperalgesia of the knee. CLINICAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registration number; 000041190.

Promising Effect of Visually-Assisted Motor Imagery Against Arthrogenic Muscle Inhibition - A Human Experimental Pain Study.

PURPOSE: Clinically, arthrogenic muscle inhibition (AMI) has a negative impact on functional recovery in musculoskeletal disorders. One possible technique to relieve AMI is motor imagery, which is widely used in neurological rehabilitation to enhance motor neuron excitability. The purpose of this study was to verify the efficacy of visually-assisted motor imagery against AMI using a human experimental pain model. METHODS: Ten healthy volunteers were included. Experimental ankle pain was induced by hypertonic saline infusion into unilateral Kager's fat pad. Isotonic saline was used as control. Subjects were instructed to imagine while watching a movie in which repetitive motion of their own ankle or fingers was shown. H-reflex normalized by the motor response (H/M ratio) on soleus muscle, maximal voluntary contraction (MVC) force of ankle flexion, and contractile activities of the calf muscles during MVC were recorded at baseline, pre-intervention, post-intervention, and 10 minutes after the pain had subsided. RESULTS: Hypertonic saline produced continuous and constant peri-ankle pain (VAS peak [median]= 6.7 [2.1-8.4] cm) compared to isotonic saline (0 [0-0.8] cm). In response to pain, there were significant decreases in the H/M ratio, MVC and contractile activities (P<0.01), all of which were successfully reversed after the ankle motion imagery. In contrast, no significant changes were observed with the finger motion imagery. CONCLUSION: Visually-assisted motor imagery improved the pain-induced AMI. Motor imagery of the painful joint itself would efficiently work for relieving AMI. This investigation possibly shows the potential of a novel and versatile approach against AMI for patients with musculoskeletal pain.

Association of subchondral bone marrow lesion localization with weight-bearing pain in people with knee osteoarthritis: data from the Osteoarthritis Initiative.

BACKGROUND: Subchondral bone marrow lesions (BMLs) detected on MRI in knee osteoarthritis (OA) are associated with knee pain. The prevalence and progression of subchondral BMLs are increased by mechanical knee load. However, associations of subchondral BML location with weight-bearing knee pain are currently unknown. In this study, we aim to demonstrate associations of subchondral BML location and size with weight-bearing knee pain in knee OA. METHODS: We analyzed 1412 and 582 varus knees from cross-sectional and longitudinal Osteoarthritis Initiative datasets, respectively. BML scores were semi-quantitatively analyzed with the MRI Osteoarthritis Knee Score for 4 subchondral regions (median and lateral femorotibial, medial and lateral patellofemoral) and subspinous region. Weight-bearing and non-weight-bearing pain scores were derived from WOMAC pain items. Correlation and negative binomial regression models were used for analysis of associations between the BML scores and pain at baseline and changes in the BML scores and changes in pain after 24-month follow-up. RESULTS: Greater BML scores at medial femorotibial and lateral patellofemoral compartments were associated with greater weight-bearing pain scores, and statistical significance was retained after adjusting for BML scores at the other 4 joint compartments and other OA features, as well as for non-weight-bearing pain, age, sex, and body mass index (BMI) (medial femorotibial; B = 0.08, p = 0.02. patellofemoral; B = 0.13, p = 0.01). Subanalysis revealed that greater medial femorotibial BML scores were associated with greater pain on walking and standing (B = 0.11, p = 0.01, and B = 0.10, p = 0.04, respectively). Lateral patellofemoral BML scores were associated with pain on climbing, respectively (B = 0.14, p = 0.02). Increases or decreases over 24 months in BML score in the medial femorotibial compartment were significantly associated with increases or decreases in weight-bearing pain severity after adjusting for non-weight-bearing pain, age, sex, baseline weight-bearing pain, BMI, and BML at the other 4 joint compartments (B = 0.10, p = 0.01). CONCLUSIONS: Subchondral BML size at the medial femorotibial joint compartment was specifically associated with the severity and the change in weight-bearing pain, independent of non-weight-bearing pain, in knee OA. Specific associations of weight-bearing pain with subchondral BMLs in weight-bearing compartments of the knee indicate that BMLs in subchondral bone contribute to biomechanically induced OA pain.

Chronic postsurgical pain after total knee arthroplasty: A prospective cohort study in Japanese population.

OBJECTIVES: To elucidate the prevalence and risk factors of chronic postsurgical pain (CPSP) after primary total knee arthroplasty (TKA) in Japanese population. METHODS: Consecutive patients undergoing primary TKA in a Japanese tertiary hospital (211 knees) were assessed. CPSP after TKA was defined as moderate to severe pain (VAS >30 mm), either at rest or during walking, one year after surgery. Clinical and radiographic data were compared between CPSP and non-CPSP groups and multivariate logistic regression was used to identify predictors of CPSP. RESULTS: The prevalence of CPSP was 8.8%. CPSP group showed significantly higher preoperative WOMAC subscales (pain, function and stiffness), higher rate of postoperative coronal malalignment (femorotibial angle >178° or <170°) and larger varus angle of tibial component compared with non-CPSP group. Logistic regression analysis revealed that preoperative higher WOMAC pain and postoperative coronal malalignment were independent risk factors of CPSP. In a subgroup analysis of patients with well-aligned TKA, preoperative pain VAS at rest was the only risk factor of CPSP. CONCLUSION: Preoperative severe pain and postoperative coronal malalignment were independent risk factors of CPSP after TKA. Preoperative pain management in patients with severe pain and good coronal alignment after TKA possibly minimize the development of CPSP.

Accuracy of acetabular cup placement using an angle-adjusting alignment guide with laser pointer in total hip arthroplasty.

PURPOSE: To evaluate cup-positioning accuracy in total hip arthroplasty (THA) using a novel angle-adjusting alignment guide with laser pointer and determine whether level of surgical experience affects accuracy of cup placement or not. METHODS: We included 117 hips in 104 patients who underwent THA using the novel guide. We retrospectively reviewed 44 hips in 40 patients who underwent THA before the novel guide was introduced. We compared differences in cup angles between the novel guide group and the conventional guide group as well as the discrepancies in targeted angles between the experienced surgeon group and the inexperienced surgeon group. RESULTS: There were 114/117 hips (97.4%) within the Lewinnek safe zone in the novel guide group and 32/44 hips (72.7%) within the safe zone in the conventional guide group. There were significantly fewer outliers in the novel guide group (p < 0.001). In the experienced surgeon group, the mean absolute errors in inclination and anteversion were 2.0 ± 1.7° and 2.1 ± 2.3°, respectively; which were not significantly different from those in the inexperienced surgeon group (2.3 ± 2.1° and 2.8 ± 2.3°, respectively). CONCLUSION: The novel angle-adjusting alignment guide with laser pointer is a simple tool that provides better accuracy of cup position than that obtained using conventional guides. Accurate cup placement is possible using the novel guide, regardless of surgeons' experience.

Associations of Symptomatic Knee Osteoarthritis With Histopathologic Features in Subchondral Bone.

OBJECTIVE: Subchondral bone and the osteochondral junction are thought to contribute to osteoarthritis (OA) knee pain. We undertook this study to identify osteochondral pathologies specifically associated with symptomatic human knee OA. METHODS: Medial tibial plateau samples from 2 groups of subjects (n = 31 per group) were matched for macroscopic chondropathy scores. The symptomatic chondropathy group had undergone total knee replacement for OA knee pain, at which time specimens of the medial tibial plateau were obtained. The asymptomatic chondropathy group included subjects who died of unrelated illness (specimens were obtained at postmortem examination) and who had not previously sought help for knee pain. OA histopathology, immunoreactivity for nerve growth factor (NGF) and CD68 (macrophages), tartrate-resistant acid phosphatase-positive subchondral osteoclasts, and synovitis were compared between groups. RESULTS: Mankin scores, subchondral bone density, and subchondral CD68-immunoreactive macrophage infiltration were similar between the 2 groups. NGF-like immunoreactivity was found in subchondral mononuclear cells and osteoclasts, as well as in chondrocytes. NGF in osteochondral channels and osteoclast densities in subchondral bone were higher in the symptomatic chondropathy group than in the asymptomatic chondropathy group (P < 0.01 and P = 0.02, respectively), as were synovitis scores (P < 0.01). Osteochondral pathology was not significantly associated with synovitis score. The differences in NGF expression and in osteoclast density remained significant after adjustment for age and synovitis score (P = 0.01 and P = 0.04, respectively). Osteochondral NGF and osteoclast densities, together with synovitis scores, explained ~28% of sample allocation to symptomatic or asymptomatic groups. CONCLUSION: Subchondral pathology was associated with symptomatic knee OA, independent of chondropathy and synovitis. Increased NGF expression in osteochondral channels and increased osteoclast density appear to be key features associated with bone pain in knee OA.

Association between Falls and Balance among Inpatients with Schizophrenia: A Preliminary Prospective Cohort Study.

Falls are adverse events affecting psychiatric inpatients that can lead to external injuries, fractures, and death. However, none have attempted to examine fall-related factors, particularly focused on balance, specifically among inpatients with schizophrenia. The present preliminary study aimed to assess the association between falls and balance in patients with schizophrenia. The authors performed baseline assessments of background factors, postural sway, and maximum step length in 120 patients with schizophrenia hospitalized in the psychiatric ward. A prospective 3-month follow-up was conducted, and participants were divided into a fall or non-fall group according to their history of falls during the follow-up. Variance among individual variables was compared between the fall group and non-fall group using the t-test, Mann-Whitney U test, and chi-square test. A total of 16 participants experienced falls in the 3-month follow-up period (13.3%). Comparative factor analysis revealed significant differences between the fall and non-fall groups in terms of the presence or absence of falls within 3 months before follow-up (p = 0.002) and Romberg quotients for sway length (p = 0.02). These findings suggest that fall history could be considered a predictor of future falls, which could help with fall prevention, and that assessment of visual contribution to postural control using the Romberg quotient could play an important role in fall prevention.

Additional benefit of local infiltration of analgesia to femoral nerve block in total knee arthroplasty: double-blind randomized control study.

PURPOSE: Multimodal analgesia has become an important concept in current pain management following total knee arthroplasty (TKA). However, controversy remains over what is the most accepted combination. In this study, the additional benefits of local infiltration of analgesia to femoral nerve block were evaluated. METHODS: Forty patients were randomly allocated into a combined local infiltration of analgesia and femoral nerve block or femoral nerve block alone group. In the former, analgesic drugs consisting of ropivacaine and dexamethasone were injected into the peri-articular tissues, while the same amount of saline was injected into the femoral nerve block group. The primary outcome measure was the total amount of fentanyl consumption by the patient-controlled analgesia pump during the 48-h post-operative period. RESULTS: A combination of local infiltration of analgesia and femoral nerve block had less total fentanyl consumption and a larger knee ROM at post-operative day 2 than femoral nerve block alone (p < 0.05). C-reactive protein levels in the combined treatment group were significantly lower than the femoral nerve block group at post-operative day 3 (p < 0.01). There was no difference between the two groups, post-operatively, on the visual analogue scale for pain at rest or while walking, quadriceps strength, timed up and go test, circumference of thigh, Knee Society Score, and Western Ontario and McMaster Universities Osteoarthritis Index. CONCLUSION: The addition of local infiltration of analgesia to femoral nerve block promoted post-operative pain relief and the recovery of knee ROM in the early post-operative period. This combination is an effective method for post-operative pain management after TKA. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

Efficacy and Limitations of Conservative Treatment for Painful Patella Partita: Positioning of an Ultrasound-Accelerated Fracture Healing Apparatus.

OBJECTIVE: Generally, painful patella partita is conservatively treated, but the usefulness of a low-intensity pulsed ultrasound (LIPUS) healing apparatus is unclear. The objective of this study was to investigate the usefulness of LIPUS for conservative treatment of painful patella partita. SUBJECTS AND METHODS: The subjects included 17 patients diagnosed with painful patella partita. The subjects were divided into 2 groups: those without pain at 6 months (responsive group) and those with pain that persisted for 6 months or longer (non-responsive group). The reasons for the different responses between the 2 groups were investigated. We evaluated various factors, including age, gender, presence or absence of epiphyseal closure on plain xp at the first examination, Saupe classification, presence or absence of bone union, and type of conservative treatment. The grade of limitation of movement, the presence or absence of instruction on quadriceps femoris muscle stretch, and use of an orthosis and LIPUS were also investigated. RESULTS: The responsive and non-responsive groups consisted of 12 and 5 patients, respectively, and included only male patients. The average age was 13 and 16 years old in the responsive and non-responsive groups, respectively. Epiphyseal closure was present in 1 of the 12 patients in the responsive group and 3 of the 5 patients in the non-responsive group. The Saupe classifications in the responsive and in the non-responsive groups, respectively, were type I in 1 and 2 patients (3 total), type II in 6 and 1 patients (7 total), and type III in 4 and 3 patients (7 total). Bone union was achieved in 10 patients in the responsive group, whereas no patient achieved bone union and 3 patients underwent excision in the non-responsive group. Conservative treatment in the responsive and non-responsive groups, respectively, included prohibition of exercise for 7 and 2 patients (9 total) and instruction on quadriceps femoris muscle stretch for 5 and 2 patients (7 total). In addition, all of the 8 patients wearing an orthosis and 2 patients treated with LIPUS were in the responsive group. DISCUSSION: The findings suggest that painful Saupe type II patella partita can be improved by appropriate conservative treatment before epiphyseal closure. LIPUS may be advantageous for bone union and pain relief.

Chronological changes in functional cup position at 10 years after total hip arthroplasty.

PURPOSE: This study aims to clarify the chronological changes in functional cup position at a minimum follow-up of 10 years after total hip arthroplasty (THA), and to identify the risk factors influencing a significant difference in functional cup position during the postoperative follow-up period. METHODS: We evaluated the chronological changes in functional cup position at a minimum follow-up of 10 years after THA in 58 patients with unilateral hip osteoarthritis. Radiographic cup position was measured on anteroposterior pelvic radiographs with the patient in the supine position, whereas functional cup position was recorded in the standing position. Radiographs were obtained before, 3 weeks after, and every 1 year after surgery. RESULTS: Functional cup anteversion (F-Ant) increased over time, and was found to have significantly increased at final follow-up compared to that at 3 weeks after surgery (p<0.01). The maximum postoperative change in F-Ant was 17.0° anteriorly; 12 cases (21%) showed a postoperative change in F-Ant by >10° anteriorly. Preoperative posterior pelvic tilt in the standing position and vertebral fractures after THA were significant predictors of increasing functional cup anteversion. CONCLUSIONS: Although chronological changes in functional cup position do occur after THA, their magnitude is relatively low. However, posterior impingement is likely to occur, which may cause edge loading, wear of the polyethylene liner, and anterior dislocation of the hip. We believe that, for the combined anteversion technique, the safe zone should probably be 5°-10° narrower in patients predicted to show considerable changes in functional cup position compared with standard cases.