The effect of age, speed, and arm dominance on shoulder function in untrained men

Effects of age and sex on shoulder biomechanics and relative effort during functional tasks

Age-related decline in muscle strength can compromise shoulder function, which could increase the effort needed to perform activities of daily living (ADLs). The purpose of this cross-sectional study was to determine for the first time the relative shoulder effort during ADLs in healthy young and older adults. Ten healthy young adults and ten healthy older adults were tested for maximal isokinetic torque and on a set of ADL tasks. Using inverse dynamics, the shoulder torques during ADLs were referenced to the maximal isokinetic torque and relative effort was determined. Older compared to younger adults had >40% lower isokinetic shoulder abduction strength. The ratio of peak joint torque during six ADLs over the maximal isokinetic torque, i.e., relative effort, was higher in old (∼52%) compared with young adults (∼22%, p < 0.05). Relative effort in older adults was over 40% in overhead activities and particularly high in abduction and reaching tasks, over 60%. Healthy older compared with younger adults perform most ADL tasks involving the shoulder joint with nearly twice the level of relative effort. The concomitant reductions in maximal shoulder isokinetic torque and increases in relative effort may be related to the high prevalence of musculoskeletal pain and shoulder dysfunction in old age reported in epidemiological studies.

The impacted varus (A2.2) proximal humeral fracture Prediction of outcome and results of nonoperative treatment in 99 patients

BACKGROUND AND PATIENTS: The outcome of the impacted varus proximal humeral fracture has not been described. We present the results of a prospective analysis of 99 such fractures.

RESULTS

This fracture was relatively common in the elderly population and non-operative treatment sometimes resulted in increased varus angulation. Decreased shoulder function was associated with increasing age but not with increasing varus angulation. After nonoperative management the outcome was good, regardless of the degree of varus, 1 year after fracture. Age was the main predictor of outcome. Physiotherapy did not improve outcome.

Minimally displaced proximal humeral fracturesEpidemiology and outcome in 507 cases

We analyzed 507 consecutive minimally displaced proximal humeral fractures and showed that, if the AO classification is used, there is variation in the incidence of minimally displaced fractures in the different AO sub-groups. Patients with Type A minimally displaced fractures are significantly younger than those with Type B or C fractures. 376 patients were followed for 1 year and 88% achieved excellent or good results with nonoperative management. Age was the main determinant of outcome, according to the Neer score and the time taken to return to activities of daily living. Subjectively, older patients felt that the results of treatment were better than the objective measurement of gleno-humeral function would indicate. Many patients with fair or poor results had co-morbidities that prevented a good result. The length of the physiotherapy course affected the outcome at 1 year.

Open screw fixation of large anterior glenoid rim fractures: mid- and long-term results in 29 patients

The aim of this retrospective study was to analyse the clinical, functional and radiographic outcomes of patients sustaining traumatic anterior dislocations of the shoulder in combination with large anterior glenoid rim fractures, treated by open reduction and internal screw fixation (ORIF). Twenty-nine patients with a mean follow-up of 6.5 years (2.5-12 years) were evaluated clinically using the Constant and DASH scores, radiographs in two planes and isokinetic muscle strength measurement (Biodex 3 PRO). Mean age was 41.6 years (17-68 years). There was no case of postoperative re-dislocation. Eight out of 29 patients (27.5%) underwent revision surgery to remove the screws. The mean age- and gender-adjusted Constant score was 93.3% (range 64-102%), and the mean DASH score was 10.1 points (range 0-71 points). On radiological examination, 6 patients had signs of osteoarthritis: Samilson type I (n = 3) and II (n = 3). Significant differences for maximal strength in external rotation and muscular endurance compared to the unaffected side were found (P < 0.035). Twenty-seven patients (93%) were satisfied or very satisfied with the result after surgery. ORIF seems to be a good treatment option in cases of large glenoid rim fractures to avoid re-dislocation in the mid-term. Prospective randomised studies are necessary to compare these findings with those after non-operative or arthroscopic treatment of these injuries.

Percutaneous fixation of displaced proximal humeral fractures: indications based on the correlation between clinical and radiographic results

We evaluated 74 patients with displaced proximal humeral fractures (mean age, 70.9 years) treated with closed reduction and percutaneous pinning. Fractures were classified radiographically following Neer's system, and the quality of reduction was assessed according to Kristiansen and Kofoed. Patients were also evaluated clinically with the Constant scale. Overall, the reduction was good in 72% of fractures, but the probability of obtaining a satisfactory reduction of displaced tuberosities was significantly lower in comparison to the humeral head. Four-part fractures obtained the worst radiographic results. The mean Constant scores were 65.8 +/- 18 points for the injured shoulder and 79.5 +/- 9.1 points for the opposite shoulder. Clinical results correlated with the quality of reduction. Closed reduction and percutaneous pinning should be reserved for 2-part fractures, but the technique can also be used in 3-part fractures in elderly patients, in whom an incomplete reduction can yield satisfactory clinical results.

Volume changes of supraspinatus and infraspinatus muscles after supraspinatus tendon repair: a magnetic resonance imaging study

Muscle volume was measured, by use of magnetic resonance imaging (MRI), as a direct indicator of functional recovery of the supraspinatus and infraspinatus muscles after supraspinatus tendon repair, because atrophy of the supraspinatus and infraspinatus muscles was observed in all patients with a torn supraspinatus tendon. Seventy-three patients who had a cuff tear limited only to the supraspinatus tendon were included in this study. The University of California, Los Angeles score improved significantly after surgery. MRI was carried out before surgery and 6, 12, and 24 months postoperatively in all patients. Muscle volume of the supraspinatus was assessed on images of the oblique coronal plane, and that of the infraspinatus was assessed on images of the axial plane. The width of the supraspinatus muscle did not recover until 6 months postoperatively. Direct measurement of the infraspinatus muscle volume by use of MRI can be a good indicator when evaluating whether the repaired rotator cuffs are actually functioning.

Proximal humeral fractures with minimal displacement treated conservatively

We reviewed 27 patients with a minimally displaced proximal humeral fracture treated conservatively after a mean follow-up of 25 (12-34) months. All fractures had united. Patients were evaluated using the Constant-Murley scoring system, and isokinetic muscle strength was tested using a Cybex dynamometer. Finally, all shoulders were examined ultrasonographically. The mean Constant score for all patients were 81 (54-100). Twenty-three patients had no or only mild pain, while three had moderate and one severe pain necessitating regular use of oral analgesics. Twenty patients were able to perform all activities of daily living, but seven had mild trouble in overhead activities and weight carrying. Only in one patient, the abduction peak torque equalled the one of the opposite shoulder. In all other patients, the peak torque was lower than, and in 14 patients below, 50%. In nine patients, rotator cuff tears were seen at ultrasonography.

Donor Site Morbidity After Serratus Anterior Free Muscular Flap: A Prospective Clinical Study

This study was designed to assess donor site morbidity after using the serratus anterior muscle as a free vascularized flap. The 3 distal slips of the serratus anterior were harvested from 3 dominant and 4 nondominant shoulders of 7 consecutive patients (age range, 36-61 years) to treat chronic osteitis or infected nonunions of the lower limb. Both donor and recipient sites healed primarily in all patients. Six of the 7 patients were enrolled in a postoperative shoulder-strengthening program. Preoperative and 3-month follow-up Constant scores and peak torque values of the operated shoulders were compared using the Wilcoxon matched pairs signed rank test. The pre- and postoperative Constant score were 95% and 93% respectively. Peak shoulder torque for abduction, adduction, flexion, and extension was assessed at both 60 degrees /second and 120 degrees /second. No statistical differences were found between the pre- and postoperative values. At the final follow-up (mean, 17 months), clinical examination revealed no scapular winging in all patients. Six patients answered a self-administered questionnaire to assess function of the shoulder. The average score in the pain domain was 36.3 points (with 40 points meaning free of pain). The average score in the activities of daily living domain was 18.5 of 20 points. The overall satisfaction rate with the donor site was very good in 2 patients and good in 4 patients. In conclusion, removal of the 3 distal slips of the serratus anterior for use as a free vascularized transfer did not impair shoulder function in this group of patients.

Stature, age, and gender effects on reach motion postures

The rapid adoption of software to simulate human reach motions in the design of vehicle interiors and manufacturing and office workstations has required a sophisticated understanding of human motions. This paper describes how more than 3,000 right-arm reaching motions of a diverse group of participants were captured and statistically modeled. The results demonstrate that stature and age have a larger effect than does gender on reach motion postures for motions chosen by the participants while reaching to targets placed throughout a typical automobile interior. We propose that these methods, models, and results can assist the further development of human motion simulation software for ergonomic purposes, such as for the design or evaluation of vehicle interiors or industrial workplaces, to ensure that various population groups are physically accommodated.