Background: Although shoulder hemiarthroplasty (SHA) can improve function in osteoarthritic shoulders, the ability to perform activities of daily living (ADL) may remain impaired. Shoulder surgeons routinely measure parameters such as range of motion, pain, satisfaction and strength. A common subjective assessment of ADL is part of the Constant Score (CS). However, there is limited objective evidence on whether or not shoulder hemiarthroplasty can restore normal range of motion (ROM) in ADL.
Methods: The study included eight consecutive patients (n=8; seven women, one man), who underwent SHA for glenohumeral osteoarthritis. The patients were examined the day before, as well as 6 months and 3 years after shoulder replacement. They were compared with a control group with no shoulder pathology, and shoulder movement was measured with 3D motion analysis using the "Heidelberg Upper Extremity" (HUX) model. Measurements included static maximum values and four ADL.
Results: Comparing the preoperative to the 3-year postoperative static maximum values, there were significant improvements for abduction from 50.5° (SD ± 3 2.4°) to 72.4° (SD ± 38.2°; p=0.031), for adduction from 6.2° (SD ± 7.7°) to 66.7° (SD ± 18.0°; p=0.008), for external rotation from 15.1° (SD ± 27.9°) to 50.9° (SD ± 27.3°; p=0.031), and for internal rotation from -0.6° (SD ± 3.9°) to 35.8° (SD ± 28.2°; p=0.031). There was a trend of improvement for flexion from 105.8° (SD ± 45.7°) to 161.9° (SD ± 78.2°; p=0.094) and for extension from 20.6° (SD ± 17.0°) to 28.0° (SD ± 12.5°; p=0.313). The comparison of the 3-year postoperative ROM between the SHA group and controls showed significant differences in abduction; 3-year postoperative SHA ROM 72.4° (SD ± 38.2°) vs. 113.5° (SD ± 29.7°) among controls (p=0.029). There were no significant differences compared to the control group in adduction, flexion/extension and rotation 3 years after SHA surgery. In performing the ADL, the pre- to the 6-month and 3-year postoperative status of the SHA group resulted in a significant increase in ROM in all planes (p<0.05). Comparing the preoperative to the 3-year postoperative ROM used in ADL, there was an improvement in the flexion/extension plane, showing an improvement trend from preoperative 85°-0°-25° to postoperative 127°-0°-38° (p=0.063). In comparison, controls used a significantly greater ROM during ADL with mean flexion/extension of 139°-0°-63° (p=0.028). For the abduction/adduction plane, ROM improved significantly from preoperative 25°-0°-19° to postoperative 78°-0°-60° (p=0.031). In comparison to controls with abduction/adduction of 118°-0°-37° 3 years postoperative, the SHA group also used significantly less ROM in the abduction/adduction plane (p=0.028).
Conclusion: While SHA improves ROM in ADL in patients with degenerative glenohumeral osteoarthritis, it does not restore the full ROM available for performing ADL compared to controls. 3D motion analysis with the HUX model is an appropriate measurement system to detect surgery-related changes in shoulder arthroplasty.
Keywords: 3D motion analysis; Activity of daily living; Marker-based system; Shoulder hemiarthroplasty; Upper extremity.
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