Revision rates of trapeziometacarpal total joint arthroplasty in relation to occupational hand force requirements.

The purpose was to determine revision rates after trapeziometacarpal total joint arthroplasty in working age patients, hypothesizing that higher occupational hand force requirements lead to higher revision rates. We conducted a follow-up study of patients operated 2003-2015. Self-reported job titles at the time of primary surgery were linked with a job exposure matrix to estimate occupational hand force requirements. Time until revision was analysed using Cox regression. The study comprised 222 patients aged 39-65 years (mean 55, SD 6), including 133 patients in the labour market. The median follow-up period was 5 years (interquartile range 4-7) and the overall revision rate was 5/100 person-years. For high versus low occupational hand force requirements, the hazard ratio was 1.5 (95% confidence interval 0.5-4.4). For patients outside the labour market, the hazard ratio was 2.3 (0.9-5.6). Our results did not indicate large effects of high occupational hand force requirements on revision rates.Level of evidence: IV.

Three-dimensional kinematics of shoulder function in stroke patients: Inter- and intra-rater reliability.

BACKGROUND: It is important to monitor progress during rehabilitation of stroke patients. To that end, clinical function tests may be supported by three-dimensional kinematic measures. The aim of this study was to evaluate the inter- and intra-rater reliability of three-dimensional kinematic measures of shoulder movements in stroke patients with reduced shoulder function. METHODS: Seventeen patients were tested in three sessions by two trained raters. Three-dimensional motion capture was performed of the more affected upper extremity and the trunk. Measures of movements of the scapula and humerus related to the trunk, the trunk related to the laboratory, the forearm related to the humerus, and temporospatial measures were obtained during two reach tasks from the Wolf Motor Function Test, ReachLow and ReachHigh. Inter- and intra-rater reliability was quantified with intraclass correlation coefficients (ICC). FINDINGS: In general, range of movements of scapula, shoulder, trunk and elbow and movement time and reach length showed high inter-rater reliability (ICC∞ 0.84-0.98) and intra-rater reliability (ICC∞ 0.75-1.00), A minimum of five trials per task were required to achieve reliable ICC estimates. INTERPRETATION: Selected three-dimensional kinematic measures can be used reliably to evaluate specific movements of the shoulder in stroke patients with reduced shoulder function.

Shoulder function and work disability after decompression surgery for subacromial impingement syndrome: a randomised controlled trial of physiotherapy exercises and occupational medical assistance.

BACKGROUND: Surgery for subacromial impingement syndrome is often performed in working age and postoperative physiotherapy exercises are widely used to help restore function. A recent Danish study showed that 10% of a nationwide cohort of patients retired prematurely within two years after surgery. Few studies have compared effects of different postoperative exercise programmes on shoulder function, and no studies have evaluated workplace-oriented interventions to reduce postoperative work disability. This study aims to evaluate the effectiveness of physiotherapy exercises and occupational medical assistance compared with usual care in improving shoulder function and reducing postoperative work disability after arthroscopic subacromial decompression. METHODS/DESIGN: The study is a mainly pragmatic multicentre randomised controlled trial. The trial is embedded in a cohort study of shoulder patients referred to public departments of orthopaedic surgery in Central Denmark Region. Patients aged ≥18-≤63 years, who still have shoulder symptoms 8-12 weeks after surgery, constitute the study population. Around 130 participants are allocated to: 1) physiotherapy exercises, 2) occupational medical assistance, 3) physiotherapy exercises and occupational medical assistance, and 4) usual care. Intervention manuals allow individual tailoring. Primary outcome measures include Oxford Shoulder Score and sickness absence due to symptoms from the operated shoulder. Randomisation is computerised with allocation concealment by randomly permuted block sizes. Statistical analyses will primarily be performed according to the intention-to-treat principle. DISCUSSION: The paper presents the rationale, design, methods, and operational aspects of the Shoulder Intervention Project (SIP). SIP evaluates a new rehabilitation approach, where physiotherapy and occupational interventions are provided in continuity of surgical episodes of care. If successful, the project may serve as a model for rehabilitation of surgical shoulder patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN55768749.

Total hip replacement due to primary osteoarthritis in relation to cumulative occupational exposures and lifestyle factors: a nationwide nested case-control study.

OBJECTIVE: To investigate the risk of total hip replacement (THR) due to primary osteoarthritis in relation to cumulative occupational mechanical exposures and lifestyle factors. METHODS: Using register information, we identified first-time THR cases within the Danish working population in 2005-2006. For each case, 2 age- and sex-matched controls were drawn. Persons within 2,500 randomly selected case-control sets received a questionnaire about job history, weight at age 25 years, present weight and height, smoking, and sports activities at age 25 years. The job history was combined with a job exposure matrix. Cumulative exposure estimates were expressed according to the pack-year concept of smoking (e.g., cumulative lifting was expressed as ton-years). We used conditional logistic regression for statistical analyses. RESULTS: In total, 1,776 case-control sets (71%) were available for analysis. The adjusted odds ratio (OR) for exposure to ≥20 ton-years was 1.35 (95% confidence interval [95% CI] 1.05-1.74) for men and 1.00 (95% CI 0.73-1.41) for women. Standing/walking and whole body vibration showed no associations. The adjusted OR for body mass index (BMI) ≥30 kg/m(2) at age 25 years was 2.44 (95% CI 1.38-4.32) for men and 5.12 (95% CI 2.30-11.39) for women. The corresponding adjusted ORs for an increase in BMI of ≥10 kg/m(2) since age 25 years were 2.16 (95% CI 1.25-3.70) and 2.46 (95% CI 1.47-4.13). Sports participation showed weak positive associations, while pack-years of smoking showed no associations. CONCLUSION: The results indicated a modest increase in risk of THR in relation to cumulative lifting among men and an increased risk in relation to a high BMI at age 25 years and to a gain in BMI in both sexes.

Lifestyle risk factors for ulnar neuropathy and ulnar neuropathy-like symptoms.

INTRODUCTION: We examined whether lifestyle factors differ between patients with ulnar neuropathy confirmed by electroneurography (ENG) and those with ulnar neuropathy-like symptoms with normal ulnar nerve ENG. METHODS: Among patients examined by ENG for suspected ulnar neuropathy, we identified 546 patients with ulnar neuropathy and 633 patients with ulnar neuropathy-like symptoms. These groups were compared with 2 separate groups of matched community referents and to each other. Questionnaire information on lifestyle was obtained. The electrophysiological severity of neuropathy was also graded. We used conditional and unconditional logistic regression. RESULTS: Responses were obtained from 59%. Ulnar neuropathy was related to smoking, adjusted odds ratio (OR) 4.31 (95% confidence interval [CI] 2.43-7.64) for >24 pack-years. Ulnar neuropathy-like symptoms were related to body mass index ≥30 kg/m(2), OR 1.99 (95% CI 1.25-3.19). Smoking was associated with increased severity of ulnar neuropathy. CONCLUSIONS: Findings suggest that smoking specifically affects the ulnar nerve.

Muscle fatigue in relation to forearm pain and tenderness among professional computer users.

BACKGROUND: To examine the hypothesis that forearm pain with palpation tenderness in computer users is associated with increased extensor muscle fatigue. METHODS: Eighteen persons with pain and moderate to severe palpation tenderness in the extensor muscle group of the right forearm and twenty gender and age matched referents without such complaints were enrolled from the Danish NUDATA study of neck and upper extremity disorders among technical assistants and machine technicians. Fatigue of the right forearm extensor muscles was assessed by muscle twitch forces in response to low frequency (2 Hz) percutaneous electrical stimulation. Twitch forces were measured before, immediately after and 15 minutes into recovery of an extensor isometric wrist extension for ten minutes at 15 % Maximal Voluntary Contraction (MVC). RESULTS: The average MVC wrist extension force and baseline stimulated twitch forces were equal in the case and the referent group. After the fatiguing contraction, a decrease in muscle average twitch force was seen in both groups, but the decrease was largest in the referent group: 27% (95% CI 17-37) versus 9% (95% CI -2 to 20). This difference in twitch force response was not explained by differences in the MVC or body mass index. CONCLUSION: Computer users with forearm pain and moderate to severe palpation tenderness had diminished forearm extensor muscle fatigue response. Additional studies are necessary to determine whether this result reflects an adaptive response to exposure without any pathophysiological significance, or represents a part of a causal pathway leading to pain.

Task-based estimation of mechanical job exposure in occupational groups.

OBJECTIVES: This study examined the validity of a common belief in epidemiology with respect to work-related musculoskeletal disorders, that individual mechanical job exposure is better estimated from tasks performed in the job than from the mean exposure of the occupational group. METHODS: Whole-day recordings of upper trapezius electromyography were obtained from 24 cleaners and 23 office workers. Trapezius activity was analyzed in the level (gap time) and frequency (jerk time) dimensions. On the same day, the job of each person was divided into periods of active work and breaks by means of continuous observations. The bootstrap re-sampling technique was used with this database to compare task-based job exposure estimates with estimates based on the occupational mean. For a particular person, the task-based estimate was obtained by combining the average work and break exposures in the occupation with the personal time proportions of the two tasks in the job. RESULTS: The task-based estimates were, in general, equivalent to, or less correct than, occupation-based estimates for both exposure parameters in both occupations and for individual exposures, as well as for group means. This was the result in spite of significant and consistent exposure differences between work and breaks, in particular among the cleaners. CONCLUSIONS: Even if task exposure contrasts are large, task-based estimates of job exposures can be less correct than estimates based on the occupational mean. Since collecting and processing task information is costly, it is recommended that task-based modeling of mechanical exposure be implemented in studies only after careful examination of its possible benefits.