Increased alcohol intake is associated with radiographic severity of knee and hand osteoarthritis in men.

Observational studies have shown controversial associations between alcohol intake and radiographic osteoarthritis (OA). This study investigated whether this association was causal using a Mendelian randomization (MR) study in a population-based cohort in Korean. The study enrolled 2429 subjects (1058 men, 1371 women) from the Dong-gu Study. X-rays of the hand and knee joints were scored using a semi-quantitative grading system to calculate the total score of the hand and knee joints. ALDH2 rs671 genotyping was performed by high-resolution melting analysis. MR instrumental variable analysis and observational multivariable regression analysis were used to estimate the association between genetically predicted alcohol intake and the radiographic severity of OA. Subjects with the G/G genotype had a higher current alcohol intake than those with the G/A and A/A genotypes in both men and women (all P < 0.001). Men with the G/G genotype had higher total knee (P < 0.001) and hand scores (P = 0.042) compared to those with the G/A and A/A genotypes after adjusting for age and body mass index, but not in women. In the observational multivariable regression analysis, each alcohol drink per day in men was associated with increased knee (P = 0.001) and hand joint scores (P = 0.013) after adjustment, but not in women. In our MR analysis, utilizing ALDH2 rs671 genotypes as instrumental variables for alcohol consumption, has shown a significant link between each additional daily alcohol drink and increased radiographic joint severity in men.

Significance of High-Frequency Sonography for the Subclinical Progression of Rheumatoid Arthritis.

OBJECTIVES: This study aims to investigate the use of high-frequency sonography as a tool for detecting inflammatory and destructive changes in the hand and foot joints of patients with early and long-term RA. METHODS: This study employs a prospective cohort design involving 162 patients diagnosed with Rheumatoid arthritis (RA) who meet the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria. Patients were divided into two groups based on disease duration: Group 1 (n = 74) included patients with a disease duration of up to 2 years, or early РА (ERA;), Group 2 (n = 88) consisted of patients with a disease duration exceeding 2 years, or long-term persistent РА (LtRA). All patients underwent a clinical assessment of their joints, as well as radiography and arthrosonography, at the beginning of the study and again at 6 and 12 months later. RESULTS: In the general group of patients, ultrasound examination revealed signs of synovitis in the joints of the hands more frequently (66%) compared with clinical examination (56% by a number of swollen joints [NSJ] and 55% by a number of painful joints [NPJ], P < .01). After 6 months of treatment, 12% of the patients achieved full US remission and 24% achieved partial US remission. CONCLUSIONS: Within the scope of comprehensive RA diagnostics, arthrosonography of the joints of the hands and feet, utilizing a combination of greyscale and power Doppler, may surpass radiography in detecting early RA. This method allows for a more accurate assessment of disease activity and progression rates.

Hand osteoarthritis phenotypes based on a biopsychosocial approach, and their associations with cross-sectional and longitudinal pain.

OBJECTIVE: Hand osteoarthritis (OA) pain is characterized as heterogeneous and multifactorial. Differences in pain may be explained by underlying phenotypes, which have not been previously explored DESIGN: Latent class analysis determined classes of participants with hand OA from the Nor-Hand study baseline examination (2016-17) based on a biopsychosocial framework. Outcomes were hand and overall bodily pain intensity (Numeric Rating Scale, 0-10) at baseline and follow-up (2019-21), The relations of the classes to pain outcomes at baseline, follow-up, and change over time were analysed in separate models by linear regression, using the overall healthiest class as reference. RESULTS: Five classes differing in radiographic hand OA burden and OA burden in the lower extremities by ultrasound, demographic factors, psychosocial burden and pain sensitization was identified. Persons with the least severe OA but higher burden of biopsychosocial factors reported the most hand pain (beta 3.65, 95% CI 2.53, 4.75). Pain was less pronounced in persons with the most severe hand OA but low burden of biopsychosocial factors (beta 1.03, 95% CI 0.41, 1.65). Results were similar for overall bodily pain and at follow-up. Changes in pain were small, but the association between a separate class defined by higher levels of biopsychosocial burden and pain changes was significant. CONCLUSION: The five hand OA phenotypes were associated with pain at baseline and 3.5 years later. The phenotype with the least OA severity, but higher burden of biopsychosocial factors reported more pain than the phenotype with the most severe OA, reflecting the symptom-structure discordance of the hand OA pain experience.

Comparative effectiveness of different placebos and comparator groups for hand osteoarthritis exploring the impact of contextual factors: A systematic review and meta-analysis of randomised trials.

OBJECTIVE: To examine the pain relief effects of comparators (placebos and untreated control groups) in hand osteoarthritis trials and the impact of contextual factors. METHODS: We systematically searched PubMed, EMBASE and CENTRAL from inception to December 26, 2021. We included randomised controlled trials of people with hand osteoarthritis with a placebo or an untreated control group. We assessed the Risk of Bias with Cochrane Risk-of-Bias tool version 2. Each comparator was contrasted with a null-arm, imputed as having a zero change from baseline with the same standard deviation as the comparator. We combined the standardised mean differences with a random effects meta-analysis. The contextual factors' effect was explored in meta-regression and stratified models with pain as the dependent variable. RESULTS: 84 trials (7262 participants) were eligible for quantitative synthesis, of which 76 (6462 participants) were eligible for the stratified analyses. Placebos were superior to their matched null-arms in relieving pain with an effect size of -0.51 (95% confidence interval -0.61 to -0.42), while untreated control groups were not. When analysing all comparators, blinded trial designs and low risk of bias were associated with higher pain relief compared to an open-label trial design and some concern or high risk of bias. CONCLUSION: The placebo response on pain for people with hand osteoarthritis was increased by appropriate blinding and a lower risk of bias assessment. Placebos were superior to a null-arm, while untreated control groups were not. Results emphasise the importance of using appropriate comparators in clinical trials. PROSPERO REGISTRATION ID: CRD42022298984.

The Effectiveness of Exercise-Based Rehabilitation in People With Hand Osteoarthritis: A Systematic Review With Meta-analysis.

OBJECTIVE: To investigate the effectiveness of exercise-based rehabilitation programs compared with nonexercise intervention or no intervention for people with hand osteoarthritis (OA). DESIGN: Intervention systematic review with meta-analysis. LITERATURE SEARCH: We searched 5 databases on July 23, 2023. STUDY SELECTION CRITERIA: We included randomized controlled trials that compared the effectiveness of rehabilitation programs that included an exercise component, with nonexercise intervention or no intervention for people with hand OA. DATA SYNTHESIS: Standardized mean differences (SMDs) were pooled using a random-effects model. The risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool. The certainty of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. RESULTS: Fourteen trials were included in the meta-analysis (n = 1341 participants). In the immediate term (<24 weeks), there was low-certainty evidence of an effect of exercise-based rehabilitation on improving pain (13 trials; SMD = -0.65; 95% CI: -1.06, -0.25), function (11 trials; SMD = -0.35; 95% CI: -0.54, -0.15), and grip strength (14 trials; SMD = 0.21; 95% CI: 0.03, 0.38). There was moderate-certainty evidence of an effect on reducing stiffness (7 trials; SMD = -0.33; 95% CI: -0.51, -0.16). There was low-certainty evidence of no effect on improving pinch strength and quality of life. For the long term (≥24 weeks), there was low-certainty evidence that exercise-based rehabilitation had no additional effect on improving pain, function, and stiffness. CONCLUSION: Exercise-based rehabilitation improved pain, function, stiffness, and grip strength in people with hand OA in the immediate term; the benefits were not maintained in the long term. J Orthop Sports Phys Ther 2024;54(7):1-11. Epub 20 March 2024. doi:10.2519/jospt.2024.12241.

Small Joint Denervation of the Hand and Thumb Base: History, Anatomy, Technique, and Outcomes.

Painful arthritis of the small joints of the hand is a common condition affecting older adults, with distal interphalangeal joint and thumb carpometacarpal joint being the two most common locations. Younger adults may also develop painful arthritis after trauma and with inflammatory arthropathy. Traditional surgical approaches address the structure of the joints with either arthrodesis or arthroplasty with or without an implant. In recent decades, denervation has been reported as an alternative treatment for painful small joints that are mobile and stable. Publications on denervation often report faster surgery and recovery times than traditional surgeries that manipulate the small joint bony structures. This article reviews the history, anatomy, surgical techniques, and outcomes of denervation of the small joints of the hand.

Associations of inflammatory and metabolic biomarkers with incident erosive hand osteoarthritis in the osteoarthritis initiative cohort.

OBJECTIVE: Erosive hand osteoarthritis (eHOA) is a subtype of hand osteoarthritis (OA) that develops in finger joints with pre-existing OA and is differentiated by clinical characteristics (hand pain/disability, inflammation, and erosions) that suggest inflammatory or metabolic processes. METHOD: This was a longitudinal nested case-cohort design among Osteoarthritis Initiative participants who had hand radiographs at baseline and 48-months, and biospecimens collected at baseline. We classified incident radiographic eHOA in individuals with ≥1 joint with Kellgren-Lawrence ≥2 and a central erosion present at 48-months but not at baseline. We used a random representative sample (n = 1282) for comparison. We measured serum biomarkers of inflammation, insulin resistance and dysglycemia, and adipokines using immunoassays and enzymatic colorimetric procedures, blinded to case status. RESULTS: Eighty-six participants developed incident radiographic eHOA. In the multivariate analyses adjusted for age, gender, race, smoking, and body mass index, and after adjustment for multiple analyses, incident radiographic eHOA was associated with elevated levels of interleukin-7 (risk ratio (RR) per SD = 1.30 [95% confidence interval (CI) 1.09, 1.55] p trend 0.01). CONCLUSION: This exploratory study suggests an association of elevated interleukin-7, an inflammatory cytokine, with incident eHOA, while other cytokines or biomarkers of metabolic inflammation were not associated. Interleukin-7 may mediate inflammation and tissue damage in susceptible osteoarthritic finger joints and participate in erosive progression.

Erosive hand osteoarthritis and sarcopenia: data from Osteoarthritis Initiative cohort.

OBJECTIVES: There is no evidence linking specific osteoarthritis (OA) types, such as erosive hand OA (EHOA), with distant generalised changes in muscle composition (sarcopenia), which can potentially be modified. This study pioneers the exploration of the association between EHOA and sarcopenia, both of which are predominantly observed in the older adults. METHODS: Using the Osteoarthritis Initiative cohort, we selected hand OA (modified Kellgren and Lawrence (grade ≥2 in ≥1 hand joint) participants with radiographic central erosions in ≥1 joints (EHOA group) and propensity score-matched hand OA participants with no erosion (non-EHOA group). MRI biomarkers of thigh muscles were measured at baseline, year 2 and year 4 using a validated deep-learning algorithm. To adjust for 'local' effects of coexisting knee OA (KOA), participants were further stratified according to presence of radiographic KOA. The outcomes were the differences between EHOA and non-EHOA groups in the 4-year rate of change for both intramuscular adipose tissue (intra-MAT) deposition and contractile (non-fat) area of thigh muscles. RESULTS: After adjusting for potential confounders, 844 thighs were included (211 EHOA:633 non-EHOA; 67.1±7.5 years, female/male:2.9). Multilevel mixed-effect regression models showed that EHOA is associated a different 4-year rate of change in intra-MAT deposition (estimate, 95% CI: 71.5 mm2/4 years, 27.9 to 115.1) and contractile area (estimate, 95% CI: -1.8%/4 years, -2.6 to -1.0) of the Quadriceps. Stratified analyses showed that EHOA presence is associated with adverse changes in thigh muscle quality only in participants without KOA. CONCLUSIONS: EHOA is associated with longitudinal worsening of thigh muscle composition only in participants without concomitant KOA. Further research is needed to understand the systemic factors linking EHOA and sarcopenia, which unlike EHOA is modifiable through specific interventions.

Ensemble Learning Method for the Continuous Decoding of Hand Joint Angles.

Human-machine interface technology is fundamentally constrained by the dexterity of motion decoding. Simultaneous and proportional control can greatly improve the flexibility and dexterity of smart prostheses. In this research, a new model using ensemble learning to solve the angle decoding problem is proposed. Ultimately, seven models for angle decoding from surface electromyography (sEMG) signals are designed. The kinematics of five angles of the metacarpophalangeal (MCP) joints are estimated using the sEMG recorded during functional tasks. The estimation performance was evaluated through the Pearson correlation coefficient (CC). In this research, the comprehensive model, which combines CatBoost and LightGBM, is the best model for this task, whose average CC value and RMSE are 0.897 and 7.09. The mean of the CC and the mean of the RMSE for all the test scenarios of the subjects' dataset outperform the results of the Gaussian process model, with significant differences. Moreover, the research proposed a whole pipeline that uses ensemble learning to build a high-performance angle decoding system for the hand motion recognition task. Researchers or engineers in this field can quickly find the most suitable ensemble learning model for angle decoding through this process, with fewer parameters and fewer training data requirements than traditional deep learning models. In conclusion, the proposed ensemble learning approach has the potential for simultaneous and proportional control (SPC) of future hand prostheses.

Erosive Hand Osteoarthritis: Recent Advances and Future Treatments.

PURPOSE OF THE REVIEW: Erosive hand osteoarthritis (EHOA) is an aggressive form of hand osteoarthritis that leads to significant disability, and recent data suggests that it is increasing in prevalence. This review provides an update of our current understanding of epidemiology, genetic associations, biomarkers, pathogenesis, and treatment of EHOA, with particular focus on studies published within the last 5 years. RECENT FINDINGS: New studies of EHOA have identified new genetic loci associated with disease, including variants in genes involved in inflammation and bone remodeling. Preclinical studies implicate pathways of innate immunity, including some that may be causal in the condition. Recent novel studies showed that inflammatory features identified by ultrasound and MRI are associated with development of erosive lesions over time on conventional radiography. In the future, these imaging modalities may be useful in identifying patients at risk of adverse outcomes. Promising new findings in genetics, biomarkers, and treatment targets will hopefully allow for future therapeutic options for this debilitating condition.

Association between hyperuricaemia and hand osteoarthritis: data from the Xiangya Osteoarthritis Study.

OBJECTIVE: The pathogenesis of hand osteoarthritis (OA) remains unknown. Hyperuricaemia, which is related to inflammation, may play a role in hand OA, but evidence is lacking. In a large population-based study, we examined the association between hyperuricaemia and hand OA. METHODS: Participants were from the Xiangya OA Study, a community-based observational study. Hyperuricaemia was defined as serum urate >416 µmol/L in men and >357 µmol/L in women. Radiographic hand OA (RHOA) was defined as presence of the modified Kellgren-Lawrence grade ≥2 in any hand joint. Symptomatic hand OA (SHOA) was defined as presence of both self-reported symptoms and RHOA in the same hand. The associations of hyperuricaemia with RHOA or SHOA were examined using generalised estimating equations. RESULTS: Among 3628 participants, the prevalence of RHOA was higher in participants with hyperuricaemia than those with normouricaemia (26.9% vs 20.9%), with an adjusted OR (aOR) of 1.34 (95% CI 1.11 to 1.61). The associations were consistent in men (aOR 1.33, 95% CI 1.01 to 1.74) and women (aOR 1.35, 95% CI 1.05 to 1.74). Hyperuricaemia was mainly associated with bilateral RHOA (aOR 1.54, 95% CI 1.18 to 2.01) but not unilateral RHOA (aOR 1.13, 95% CI 0.89 to 1.45). Prevalence of SHOA was higher, although statistically insignificant, in participants with hyperuricaemia (aOR 1.39, 95% CI 0.94 to 2.07). CONCLUSION: In this population-based study, hyperuricaemia was associated with a higher prevalence of hand OA. Future prospective studies are required to investigate the temporal relationship. TRIAL REGISTRATION NUMBER: NCT04033757.

Total joint arthroplasty versus trapeziectomy in the treatment of trapeziometacarpal joint arthritis: a randomized controlled trial.

The aim of this double anonymized, randomized controlled trial was to determine whether total joint arthroplasty has superior outcomes than trapeziectomy 1 year after surgery for trapeziometacarpal osteoarthritis. A total of 62 women aged 40 years and older, scheduled for surgery for stage II or III osteoarthritis of the trapeziometacarpal joint, were included and randomized to trapeziectomy or total joint arthroplasty. The primary outcome was the total score of the Michigan Hand Outcomes Questionnaire. Secondary outcomes were the Michigan Hand Outcomes Questionnaire subscale scores, Disability of the Arm, Shoulder and Hand Questionnaire, active range of motion, strength, return to work, patient satisfaction and complications. Data were collected at baseline and at 3 and 12 months. At 1 year, we found no superiority of total joint arthroplasty over trapeziectomy regarding the total score of the Michigan Hand Outcomes Questionnaire. The total joint arthroplasty did show a significant advantage in strength and range of motion.Level of evidence: I.

Measuring Arm and Hand Joint Kinematics to Estimate Impairment During a Functional Reach and Grasp Task after Stroke.

BACKGROUND: Current approaches to characterizing deficits in upper limb movements after stroke typically focus either on changes in a functional measure, for example, how well a patient can complete a task, or changes in impairment, for example, isolated measurements of joint range of motion. However, there can be notable dissociations between static measures of impairment versus those of function. OBJECTIVE: We develop a method to measure upper limb joint angles during performance of a functional task and use measurements to characterize joint impairment in the context of a functional task. METHODS: We developed a sensorized glove that can precisely measure select finger, hand, and arm joints while participants complete a functional reach-to-grasp task involving manipulation of a sensorized object. RESULTS: We first characterized the accuracy and precision of the glove's joint angle measurements. We then measured joint angles in neurologically intact participants (n = 4 participants, 8 limbs) to define the expected distribution of joint angle variation during task execution. These distributions were used to normalize finger, hand, and arm joint angles in stroke participants (n = 6) as they performed the task. We present a participant-specific visualization of functional joint angle variance which illustrated that stroke participants with nearly identical clinical scores exhibited unique patterns of joint angle variation. CONCLUSIONS: Overall, measuring individual joint angles in the context of a functional task may inform whether changes in functional scores over recovery or rehabilitation are driven by changes in impairment or the development of compensatory strategies, and provide a quantified path toward personalized rehabilitative therapy.

Patterns of Involvement of the Hand Joints in Classical Rheumatoid Arthritis.

BACKGROUND: Symmetrical involvement of the hand joints is described as characteristic of rheumatoid arthritis (RA). Quantitative data on specific patterns of involvement are lacking. OBJECTIVE: The Brigham Rheumatoid Arthritis Sequential Study was created for observational studies of patients with RA and afforded a unique opportunity to answer these questions. METHODS: Of 1598 subjects in the Brigham Rheumatoid Arthritis Sequential Study cohort, 535 met the following criteria: (1) disease duration of 7 years or greater, (2) seropositive, and (3) hand radiographs available. Patterns in specific hand joints based on physical examination and radiographic findings obtained at entry were identified. The level of symmetry of involvement of the metacarpophalangeal (MCP) and wrist joints was determined, as was the correlation between findings on physical examination and radiographic changes in the hand joints. RESULTS: The prevalence of joint space narrowing and/or erosions in each proximal interphalangeal (PIP) joints ranged between 11% and 18%. Joint space narrowing and/or erosions in the MCPs increased radially from the fifth to the second finger. Swelling and tenderness on physical examination of both the PIPs and MCPs also increased radially although the positive predictive value of physical examination as an indicator of joint damage decreased radially. The wrist was the most common joint involved both by physical examination (67%) and radiographically (70%). The right side was more involved radiographically. Analysis of radiographic changes in individual patients revealed that symmetrical findings in the wrists and MCPs occurred in only 67% of patients. CONCLUSIONS: The study describes the pattern of involvement of the hand joints in patients with long standing RA. Findings of interest include symmetrical involvement in only 67% of patients and a discordancy between physical findings and radiographic changes most marked in the more radial PIP joints.

Serum carboxymethyllysine concentration is associated with erosive hand osteoarthritis.

OBJECTIVE: Carboxymethyllysine (CML) and homocitrulline (HCit) are the products of two non-enzymatic post-translational modifications of protein, a process related to age. We investigated whether serum CML and HCit concentrations were associated with hand osteoarthritis (HOA), especially erosive HOA. DESIGN: Serum CML and HCit were measured by using liquid chromatography coupled with tandem mass spectrometry at inclusion in 386 patients included in the DIGItal Cohort Design (DIGICOD) cohort. We investigated whether serum CML and/or HCit concentrations were associated with erosive HOA or with HOA clinical and radiological features. Moreover, we compared the tissular concentrations of CML and HCit in OA and non-OA cartilage from proximal interphalangeal and metacarpo-phalangeal (MCP) joints from human cadaveric donors. RESULTS: Median (IQR) serum CML concentration was lower in patients with erosive HOA than those with non-erosive HOA (178.7 [157.1-208.8] vs 194.7 [168.9-217.1] µmol/mol Lys, P = 0.002), but median HCit concentration did not differ between the groups (193.9 [162.9-232.0] vs 193.9 [155.9-224.6] µmol/mol Lys). Cartilage HCit and CML concentrations were not correlated with clinical features. Serum CML concentration was higher in OA than non-OA MCPs (7.0 vs 4.0 mmol/mol Lys, P = 0.01). CONCLUSIONS: Serum CML concentration was lower in erosive HOA than non-erosive HOA, and cartilage CML concentration was higher in OA than non-OA cartilage. These results encourage further studies to test whether serum CML could be a new prognostic biomarker in HOA.

The role of ultrasound synovitis scores for patients who are at risk of rheumatoid arthritis.

OBJECTIVES: The development of rheumatoid arthritis (RA) has been classified into 6 phases A-F according to the present risk factors in sequence of genes, environments, autoimmunity, arthralgia and joint swelling. To clarify the ultrasound synovitis scores in at-risk patients (phases C-E) and RA (phase F). METHODS: Patients who had been experiencing hand joint symptoms for at least 6 weeks and asymptomatic patients with positive rheumatoid factor and/or anti-cyclic citrullinated peptide antibodies were enrolled. A 40-joint ultrasonography with semiquantitative synovitis scoring for gray scale (GS) and power Doppler (PD) images was performed. RESULTS: A total of 139 patients were enrolled and classified into non-RA, phase C, phase D, phase E and phase F. Total GS scores in phases C (17.4 ± 7.0), D (16.0 ± 5.4), E (18.5 ± 7.7) and F (21.8 ± 9.1) were higher than those in non-RA (9.8 ± 4.0, P < 0.001). The total PD score in phase F (3.1 ± 4.6) was higher than that in phases C (0.2 ± 0.5), D (0.1 ± 0.4), and E (0.1 ± 0.3), as well as in non-RA (0.0 ± 0.0, P < 0.01). A total GS score ≥14 differentiated patients at risk for RA from patients with non-RA (area under curve [AUC] 0.82), while a total PD score ≥2 differentiated patients with RA from patients at risk for RA (AUC 0.71). CONCLUSION: Total GS score may differentiate patients at risk for RA from non-RA patients, while total PD score may differentiate patients with RA from those who are at risk for RA.

Meta-analysis of erosive hand osteoarthritis identifies four common variants that associate with relatively large effect.

OBJECTIVES: Erosive hand osteoarthritis (EHOA) is a severe subset of hand osteoarthritis (OA). It is unclear if EHOA is genetically different from other forms of OA. Sequence variants at ten loci have been associated with hand OA but none with EHOA. METHODS: We performed meta-analysis of EHOA in 1484 cases and 550 680 controls, from 5 populations. To identify causal genes, we performed eQTL and plasma pQTL analyses, and developed one zebrafish mutant. We analysed associations of variants with other traits and estimated shared genetics between EHOA and other traits. RESULTS: Four common sequence variants associated with EHOA, all with relatively high effect. Rs17013495 (SPP1/MEPE, OR=1.40, p=8.4×10-14) and rs11243284 (6p24.3, OR=1.35, p=4.2×10-11) have not been associated with OA, whereas rs11631127 (ALDH1A2, OR=1.46, p=7.1×10-18), and rs1800801 (MGP, OR=1.37, p=3.6×10-13) have previously been associated with hand OA. The association of rs1800801 (MGP) was consistent with a recessive mode of inheritance in contrast to its additive association with hand OA (OR homozygotes vs non-carriers=2.01, 95% CI 1.71 to 2.37). All four variants associated nominally with finger OA, although with substantially lower effect. We found shared genetic components between EHOA and other OA measures, grip strength, urate levels and gout, but not rheumatoid arthritis. We identified ALDH1A2, MGP and BMP6 as causal genes for EHOA, with loss-of-function Bmp6 zebrafish mutants displaying EHOA-like phenotypes. CONCLUSIONS: We report on significant genetic associations with EHOA. The results support the view of EHOA as a form of severe hand OA and partly separate it from OA in larger joints.