Abstract
[Purpose] We characterized the range of rotational motion around the three most used positions in elderly adults and developed an objective index for shoulder joint evaluation. [Participants and Methods] We investigated the range of rotational motion in the first, second, third, and transitional positions in 60 healthy young adults (60 shoulders) and 30 elderly adults (30 shoulders). We also examined changes in rotational range with variations in limb position. [Results] In older adults, the internal rotation range of motion was significantly lower at 30° abduction, 60° abduction, second position, 30° horizontal flexion, and third position. External rotational range of motion in elderly adults was also significantly lower in the first, second, 30° horizontal flexion, 60° horizontal flexion, third, 60° flexion, and 30° flexion positions. [Conclusion] The findings of this study provide objective measures of changes in rotational range of motion associated with different limb positions that may serve as an index for understanding age-related changes in shoulder mobility over time.
Keywords: Range of rotational motion of the shoulder joint, Age-related change, Position
INTRODUCTION
Considering that shoulder joint rotation is involved in all upper limb movements, restrictions in rotation due to contractures after shoulder joint disease can cause various limitations in activities of daily living (ADLs). Throughout our clinical practice, we have experienced many cases with limitations in ADLs associated with restrictions in shoulder joint rotation range of motion but often have difficulty improving rotational motion. Understanding the range of rotational motion and identifying limiting factors are extremely important in advancing physical therapy for patients presenting with limited rotational range of motion. To identify factors limiting rotational range of motion of the shoulder joint, which is covered with soft tissues, such as the joint capsule, muscles, and ligaments that may be limiting factors, therapists measured the range of motion across various positions and examined the condition of the joint based on changes in movement quality according to limb position, such as changes in resistance felt in the final range and how much movement is maintained compared to a reference range of motion. However, changes in resistance is a subjective evaluation that requires examiner experience. Moreover, given that the only known reference ranges of motion are the first (1st) and second (2nd) positions1) specified by the Japanese Orthopedic Association and the Japanese Society of Rehabilitation Medicine, the reference ranges of motion for comparison remains unclear. A previous study investigated the range of rotation in a total of nine positions, including the 1st and 2nd positions, among young healthy adults and clarified the range of rotation in each limb position and the changes in the range of rotation according to limb position2). Previous studies have reported that approximately 20% of elderly patients aged 65 years have shoulder joint disorders and that approximately 5% have movement limitations caused by restrictions in rotational range of motion, such as tethering movements3). Physical therapy based on an understanding of the characteristics of the rotational range of motion is as important in elderly patients as they are in adults. However, the limb-specific shoulder joint rotational range of motion among elderly patients, as well as changes in the rotational range of motion with aging, still remains unclear, complicating its comparison with that in young healthy adults. Therefore, the current study aimed to clarify age-related changes in rotational range of motion in the three most commonly used positions and the limbs in between and use the results for the rotational range of motion in each position as an objective index for shoulder joint evaluation.
PARTICIPANTS AND METHODS
Sixty young healthy adults with 60 shoulders (mean age, 25.7 ± 3.8 years; weight, 61.1 ± 9.5 kg; height, 166.5 ± 8.8 cm) and 30 elderly adults with 30 shoulders (mean age 72 ± 6.8 years, weight 57.2 ± 8.9 kg, height 162.4 ± 6.8 cm) without shoulder joint complaints were included. Participants were recruited via posting posters of research cooperation on a common bulletin board in the community. Before measurements, age, gender, and dominant hand were confirmed, and the presence or absence of a history of trauma to the shoulder, elbow, or wrist joints and the presence or absence of joint instability were evaluated. Patients with a history of injury in the dominant-side shoulder, elbow, or wrist, or those who were tested positive for joint instability were excluded. Measurements were taken at the shoulder joint on the dominant hand side. The dominant hand was defined as the hand primarily used for daily activities. The participants were fully briefed on the content of the experiment, during which they were informed of their ability to withdraw their research consent at any time. Written consent was obtained before any measurements were performed. This study was approved by the International University of Health and Welfare Graduate School Ethics Review Committee (Approval No. 13-64). For measurement postures, the participants were placed in the supine position on a bed to ensure comfort. The following nine measurement positions were used (Fig. 1): 1st, 2nd, and 3rd positions with 90° shoulder flexion (3rd), shoulder abduction 30° (abd30), shoulder abduction 60° (abd60), shoulder horizontal flexion 30° (hf30), horizontal flexion 60° (hf60), shoulder flexion 30° (flex30), and shoulder flexion 60° (flex60). The flexion, abduction, and horizontal flexion angles of each limb position were measured according to the range-of-motion measurement methods prescribed by the Japanese Orthopedic Association and the Japanese Society of Rehabilitation Medicine. All measurements were confirmed by a third party. In setting up each limb position, a goniometer was used to set the angle based on the measurement method of abduction, horizontal abduction, and flexion range of motion. The angle was fixed by a third party to ensure that the participants was in a comfortable state. The rotational range of motion was measured using image analysis software (ImageJ) (Fig. 2). The results for the total rotational range of motion, internal rotational range of motion, and external rotational range of motion in each limb position were then compared between young healthy adults and elderly participants to determine whether significant differences were present. The Mann–Whitney U test for independent samples was used for statistical analysis, with the significance level set at <5%.
Fig. 1.
Measurement position.
Fig. 2.
Measurement method.
RESULTS
Table 1 shows the sex ratio and percentage of dominant hand for young healthy adults and the elderly. Table 2 summarizes the range of motion for each limb position in young healthy adults and elderly adults. Notably, differences were observed in the total range of motion according to limb position, with higher values in the order of abd60 >2nd >hf30 and lower values in the order of 1st <3rd <flex60 in both young healthy adults and elderly participants. The total rotational range of motion at abd60, 2nd, hf30, hf60, 3rd, flex60, and flex30 was significantly lower among elderly participants than among young healthy adults. The elderly participants showed significantly lower values for internal rotation range of motion at the abd30, abd60, 2nd, hf30, and 3rd positions and for external rotation range of motion at the 1st, 2nd, hf30, hf60, 3rd, flex60, and flex30 positions than did the young healthy adults.
Table 1. Participant information.
Healthy adults | Elderly adults | |
Number of participants (n) | 60 | 30 |
Age (years) | 25.7 ± 3.0 | 72 ± 6.8 |
Male (n (%)) | 30 (50.0) | 12 (40.0) |
Female (n (%)) | 30 (50.0) | 18 (60.0) |
Hand dominant, right side (n (%)) | 52 (86.7) | 28 (93.3) |
Hand dominant, left side (n (%)) | 8 (13.3) | 2 (6.7) |
Mean ± SD or number.
Table 2. Range of motion for each limb position in young healthy adults and elderly adults.
Internal rotation range of motion | External rotation range of motion | Total rotation range of motion | |||||||
Healthy adults | Elderly adults | Healthy adults | Elderly adults | Healthy adults | Elderly adults | ||||
1st position | 47.56 ± 8.04 | 48.98 ± 6.64 | 59.09 ± 8.63 | 51.17 ± 12.92 | * | 106.65 ± 12.70 | 100.15 ± 15.68 | ||
abd30 | 61.01 ± 7.29 | 56.26 ± 9.32 | * | 72.56 ± 9.31 | 69.49 ± 13.02 | 133.57 ± 10.86 | 125.76 ± 18.30 | ||
abd60 | 64.28 ± 9.23 | 55.44 ± 14.72 | * | 82.92 ± 9.45 | 78.81 ± 11.19 | 147.20 ± 12.16 | 134.30 ± 19.56 | * | |
2nd position | 47.58 ± 11.90 | 38.84 ± 14.48 | * | 95.66 ± 10.35 | 88.86 ± 12.22 | * | 143.25 ± 12.91 | 127.70 ± 19.99 | * |
hf30 | 38.82 ± 16.68 | 32.31 ± 11.31 | * | 101.23 ± 9.61 | 95.38 ± 10.79 | * | 140.05 ± 20.42 | 127.69 ± 15.53 | * |
hf60 | 28.29 ± 9.68 | 24.77 ± 9.04 | 102.43 ± 8.30 | 95.32 ± 10.25 | * | 130.73 ± 11.79 | 120.09 ± 12.81 | * | |
3rd position | 11.82 ± 5.12 | 7.83 ± 6.38 | * | 104.23 ± 15.47 | 98.65 ± 8.17 | * | 116.05 ± 17.34 | 106.47 ± 8.58 | * |
flex60 | 89.23 ± 10.23 | 86.22 ± 11.99 | 29.35 ± 8.76 | 23.10 ± 10.48 | * | 118.58 ± 13.17 | 109.31 ± 15.67 | * | |
flex30 | 78.04 ± 14.36 | 76.18 ± 12.82 | 45.01 ± 8.27 | 36.12 ± 12.08 | * | 123.06 ± 15.78 | 112.30 ± 18.14 | * |
Mean ± SD. abd30: shoulder abduction 30°; abd60: shoulder abduction 60°; hf30: shoulder horizontal flexion 30°; hf60: horizontal flexion 60°; flex60: shoulder flexion 60°; flex30: shoulder flexion 30°. *p<0.05.
DISCUSSION
The current study aimed to clarify the age-related changes in rotational range of motion in the three most commonly used positions and the limbs in between and determined whether the results could be used as objective indices for shoulder joint evaluation. Our findings revealed significant difference between elderly and young adults in the total range of motion. Positions such as abd60, second position, and hf30 showed higher values in that order, whereas the first, third, and flex60 showed lower values in that order. Furthermore, compared to the young healthy adults, the elderly patients showed limb positions with decreased values in the total range of rotation, internal rotation range of motion, and external rotation range of motion. These differences in total rotational range of motion may be attributed to differences in the loose-packed position (LP), in which the contact surface of the joint surface is small and the tension around the joint is loosened. Given that joint conformity is lowest in the LP, factors affecting joint motion, such as the surrounding tissues, ligaments, and joint capsule, are loose. The limb positions with the highest values for total rotational range of motion were abd60, 2nd, and hf30. Considering that the LP is said to be around 55° in abduction and 30° in horizontal adduction4), the total range of motion was considered to be greater in abd60, 2nd, and hf 30, which are limb positions close to the LP. In contrast, the limb positions with smallest values were the 1st, 3rd, and flex60. Given that these positions are in a horizontal adduction position relative to the LP, the total range of motion of rotation may be small due to the influence of the posterior soft tissues. The same trend was observed in the elderly, suggesting that the total rotational range of motion depends on the positional relationship with the LP even after age-related changes in the range of motion. Regarding age-related changes in the range of gyration, our findings showed that the total range of rotation was significantly lower in the elderly patients than in the young patients across all limb positions except 1st and abd30. Previous studies have reported that age-related organic changes in collagen fibers around the joints decrease its range of motion5) and that the range of shoulder joint rotation also decreases with age, regardless of the presence or absence of disease. In the internal rotation range of motion, the elderly patients showed significantly lower values at the abd30, abd60, 2nd, hf30, and 3rd positions than did the young patients. Studies have shown that internal rotation during horizontal abduction and at 90° abduction stretches the posterior glenohumeral bursa6) and that glenohumeral ligament minor tuberosity attachment fibers and the posterior to inferior glenoid affects internal rotation during abduction7). These findings suggest that the influence of the posterior glenohumeral bursa may cause a decrease in the range of motion in elderly patients. In the external rotation range of motion, the elderly patients showed significantly lower values at 1st, 2nd, hf30, hf60, 3rd, flex60, and flex30 positions than did the young patients. External rotation in the humerolateral position is strongly influenced by the anterior glenohumeral ligament and the coracohumeral ligament7), and reports have shown that shoulder flexion increases the tension in the superior posterior glenohumeral joint8), suggesting that the coracohumeral ligament and glenohumeral joint may decreased the external rotation range of motion in elderly patients. The current study revealed that despite an overall decrease in the total rotational range of motion among the elderly patients, the differences in the total rotational range of motion according to limb position and the characteristics of the change in rotational range of motion according to limb position were similar in both young healthy and elderly adults. Changes in the range of motion with aging differed depending on the limb position and direction of rotation, highlighting the need to measure not only the three representative limb positions or a single direction but also the surrounding positions for a more comprehensive evaluation of the state of the joints. We believe that the results obtained from the current study could be used as objective indices for shoulder joint evaluation and will be useful in capturing changes in rotational range of motion over time among patients. Nonetheless, the current study has some limitations worth noting. First, the relationship between the total range of rotational motion and the LP position was not verified through comparison with the results measured in the LP position. Future studies should therefore verify the relationship between the magnitude of the total rotational range of motion and the positional relationship with LP needs based on the rotational range of motion results with the LP. Second, the scapular angle was not measured during shoulder joint rotation range of motion measurement. Given that shoulder joint rotation is a compound movement involving the scapulothoracic joint, its range of motion may be greatly affected by the scapular angle. Future studies also need to measure the scapular angles at each measurement position to verify differences in the rotational range of motion across different positions. Third, it does not account for gender differences in flexibility. Future research should increase the number of participants and conduct separate analyses for men and women.
Conflict of interest
The authors have no conflicts of interest.
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