Motion Patterns in ADLs After Total Shoulder Arthroplasty
Motion Patterns in ADLs After Total Shoulder Arthroplasty
Ten consecutive patients (n = 10; 7 women, 3 men) with a mean age of 65.0 years [SD ± 4.7] and an intact rotator cuff who received TSA for primary glenohumeral osteoarthritis were included in this study. The patients were examined the day before, 6 months and 3 years after shoulder replacement as well. The results of the 6 month follow-up were published in 2010 as 'pilot study'. The initial patient cohort at the 6 month follow-up consisted of 13 patients. During the follow-up period, three patients were lost to follow-up, leaving a total of 10 patients for three year evaluation. The dominant side was involved in four cases, the nondominant in six. Six patients were right-hand, four patients left-hand dominant. The same surgeon performed the surgery in all ten patients at the Shoulder and Elbow Section surgery on in the Orthopaedic and Trauma Surgery Clinic of the University Hospital in Heidelberg. All patients received a cemented convex polyethylene glenoid and a cemented humeral stem (Aequalis® Shoulder; Tornier, Lyon, France). The humeral head was anatomically placed in 20° to 30° of retroversion to the transepicondylar axis of the elbow. According to the classification of Walch et al., there were four A2, three B1, and three B2 glenoids. Inclusion criteria for this study were primary or secondary glenohumeral osteoarthritis. Exclusion criteria for this study were stiff shoulder, neurological and muscular diseases, comorbidity rendering the examination impossible, and in addition, lack of verbal communication, fracture prostheses, bipolar prostheses, and rotator cuff failure.
In all shoulders of the TSA group, a deltopectoral approach was used as described by Neer et al.. In no patient was a rotator cuff tear found. After subscapularis tendon detachment and capsular release, the joint was exposed. In all cases, the intraoperative joint status corresponded with the radiographic findings. The biceps tendon was always dissected close to its glenoid attachment and was tenodesed in the bicipital groove. After placing the implant, the subscapularis tendon was repaired by using three to five nonabsorbable tendon-to-tendon sutures. Drains were removed on the first day after surgery. To protect the reconstructed subscapularis tendon, the arm was placed in internal rotation in a shoulder abduction pillow for 4 weeks. Postoperatively, the shoulder was mobilized passively by a physiotherapist for 6 weeks to 60° of flexion and abduction and 0° of external rotation. Patients were asked to support these movements actively. Free ROM was allowed 6 weeks after surgery.
The control group included 10 subjects (five women and five men; 20 shoulders) who had no shoulder conditions at the time of the examination upon study entry. No surgery was performed on the controls. Matched controls had a mean age of 64 years [SD 7.3]. All controls were right-hand dominant.
All tests for this study were conducted by a single examiner. In accordance with the World Medical Association Declaration, the study protocol was approved by the ethics committee of the Heidelberg medical school (S-305/2007), and informed consent was obtained from all patients and controls. The present study was adhered to the STROBE guidelines. The patients were examined the day before shoulder arthroplasty, 6 months, and 3 years after surgery. The reference data set of the control group was collected once during the first follow-up time of the intervention group. A 12-camera motion analysis system (Vicon 612; Vicon, Lake Forest, USA) operating at 120 Hz was used to observe the motion of the patient. The spatial resolution of the system was about 1 mm. We used the HUX model as described previously by Rettig et al. and applied in some studies. HUX dynamically defines the functional center of rotation of the shoulder joint, the axis of the elbow joint, and also the center of the elbow joint with a skin "marker set" (Figure 1; we received specific consent to publish from the participant in Figure 1) and seven segments (Figure 2): thorax, clavicles, upper arms, and forearms. Sternoclavicular and glenohumeral joint were treated as a ball-and-socket joint, while the elbow was treated as a hinge joint. Translational degrees of freedom were not considered in any of these joints. The subject was prepared by placing four markers on the trunk as recommended by the International Society of Biomechanics for this measurement. In addition, four markers were placed on each forearm: one at the ulnar and one at the radial styloid process of the wrist. The other two were connected with a wand and placed on the ulna close to the elbow joint. After a static trial, the patient was asked to perform separate movements of elbow flexion/extension, shoulder flexion/extension, and shoulder abduction/adduction to determine the shoulder joint position and the location of the elbow joint axis. Specifically, in these shoulder calibration trials the sternoclavicular joint was considered a cardan joint. Technical coordinate systems for the ulna/forearm, humerus, clavicle, and thorax were not extrapolated by optimization methods as was done for marker clusters. Instead, they were grounded directly on marker trajectories, i.e., the direction vectors between them, using cross-products as demonstrated by Chiari et al..
(Enlarge Image)
Figure 1.
Skeletal model with markers and test person sitting on the chair, prepared with the markers for the 3D motion analysis using the HUX model.
(Enlarge Image)
Figure 2.
Localization of the glenohumeral joint chenter of rotation (GHJC) and measurement of an angle in the ab-/adduction plane using the HUX model.
For flexion/extension and abduction/adduction the corresponding angles between the body's long axis and the humerus were accounted for (thoracohumeral angle). The body's long axis is fixed to the thorax-TF; hence, compensatory movement of the thorax can be monitored and distinguished from shoulder movement. To determine the maximum values, the maximum ROM at flexion/extension, abduction/adduction, and also internal and external rotation was dynamically assessed. Angles of flexion/extension and abduction/adduction were expressed as projection angles relative to the proximal anatomical coordinate system. The maximum rotation, defined by the globe convention, was measured at 90° degrees of arm abduction to avoid the singularities of the convention for the hanging arm/arm in neutral position. For this, the subject sat on a stool and was instructed to move his/her arm to the respective maximum position without moving his torso. The recordings of ADLs contained the following motions: "combing the hair (cmb)", "washing the opposite armpit (wsh)", "tying an apron (aprn)", and "taking a book from a shelf (shlf)". Starting from the seated position the subject was asked to carry out these movements by trying not to move the torso. Original position was the static calibration recording and each movement was conducted three times in a row. We calculated an average maximum of the 3 trial maxima. For "combing" the subject held a comb in his/her hand and was asked to move to the forehead for combing from there to the back of the head and finally to go back to the original position. For "washing the opposite axilla" the subject held a washcloth and was asked to move it to the opposite axilla to implement a typical motion of washing there and to return to the original position. For the motion "tying an apron" the subject was asked to move the hand to the back of the torso and then return to the original position. For "taking the book" a height adjustable shelf was used. The height of the shelf was adjusted at forehead level and the book was positioned at the distance of the respective arm length centered to the test person. The subject was then asked to assume the original position place the book in his/her hand, move back to original position with the book, then to put the book back to the shelf and finally to return to the original position without the book. After extracting the motion data using the vicon software (Vicon 612; Vicon, Lake Forest, USA), all calculations were done using Microsoft Excel 2010 software. Statistical analysis was performed using SPSS Version 16.0 (SPSS Inc., Chicago, IL, USA). Group mean values (MV) and standard deviations (SD) were calculated. P values of <0.05 were considered as significant. The distribution of the data was evaluated by using the Shapiro-Wilk test and the homogeneity of variance was assessed using the Levene test. The angle between the long axis of the humerus and the trunk position was determined. The maximum and the minimum angles and the ROM for each task were monitored. The ROMs of the ADL in each plane were compared pre- and postoperative shoulder joint angles were compared by using the Wilcoxon test. As a second outcome measure, differences among these patients and the controls were examined using a Mann–Whitney U test.
Methods
TSA Group
Ten consecutive patients (n = 10; 7 women, 3 men) with a mean age of 65.0 years [SD ± 4.7] and an intact rotator cuff who received TSA for primary glenohumeral osteoarthritis were included in this study. The patients were examined the day before, 6 months and 3 years after shoulder replacement as well. The results of the 6 month follow-up were published in 2010 as 'pilot study'. The initial patient cohort at the 6 month follow-up consisted of 13 patients. During the follow-up period, three patients were lost to follow-up, leaving a total of 10 patients for three year evaluation. The dominant side was involved in four cases, the nondominant in six. Six patients were right-hand, four patients left-hand dominant. The same surgeon performed the surgery in all ten patients at the Shoulder and Elbow Section surgery on in the Orthopaedic and Trauma Surgery Clinic of the University Hospital in Heidelberg. All patients received a cemented convex polyethylene glenoid and a cemented humeral stem (Aequalis® Shoulder; Tornier, Lyon, France). The humeral head was anatomically placed in 20° to 30° of retroversion to the transepicondylar axis of the elbow. According to the classification of Walch et al., there were four A2, three B1, and three B2 glenoids. Inclusion criteria for this study were primary or secondary glenohumeral osteoarthritis. Exclusion criteria for this study were stiff shoulder, neurological and muscular diseases, comorbidity rendering the examination impossible, and in addition, lack of verbal communication, fracture prostheses, bipolar prostheses, and rotator cuff failure.
In all shoulders of the TSA group, a deltopectoral approach was used as described by Neer et al.. In no patient was a rotator cuff tear found. After subscapularis tendon detachment and capsular release, the joint was exposed. In all cases, the intraoperative joint status corresponded with the radiographic findings. The biceps tendon was always dissected close to its glenoid attachment and was tenodesed in the bicipital groove. After placing the implant, the subscapularis tendon was repaired by using three to five nonabsorbable tendon-to-tendon sutures. Drains were removed on the first day after surgery. To protect the reconstructed subscapularis tendon, the arm was placed in internal rotation in a shoulder abduction pillow for 4 weeks. Postoperatively, the shoulder was mobilized passively by a physiotherapist for 6 weeks to 60° of flexion and abduction and 0° of external rotation. Patients were asked to support these movements actively. Free ROM was allowed 6 weeks after surgery.
Controls
The control group included 10 subjects (five women and five men; 20 shoulders) who had no shoulder conditions at the time of the examination upon study entry. No surgery was performed on the controls. Matched controls had a mean age of 64 years [SD 7.3]. All controls were right-hand dominant.
Joint Angle Analysis With the HUX Model
All tests for this study were conducted by a single examiner. In accordance with the World Medical Association Declaration, the study protocol was approved by the ethics committee of the Heidelberg medical school (S-305/2007), and informed consent was obtained from all patients and controls. The present study was adhered to the STROBE guidelines. The patients were examined the day before shoulder arthroplasty, 6 months, and 3 years after surgery. The reference data set of the control group was collected once during the first follow-up time of the intervention group. A 12-camera motion analysis system (Vicon 612; Vicon, Lake Forest, USA) operating at 120 Hz was used to observe the motion of the patient. The spatial resolution of the system was about 1 mm. We used the HUX model as described previously by Rettig et al. and applied in some studies. HUX dynamically defines the functional center of rotation of the shoulder joint, the axis of the elbow joint, and also the center of the elbow joint with a skin "marker set" (Figure 1; we received specific consent to publish from the participant in Figure 1) and seven segments (Figure 2): thorax, clavicles, upper arms, and forearms. Sternoclavicular and glenohumeral joint were treated as a ball-and-socket joint, while the elbow was treated as a hinge joint. Translational degrees of freedom were not considered in any of these joints. The subject was prepared by placing four markers on the trunk as recommended by the International Society of Biomechanics for this measurement. In addition, four markers were placed on each forearm: one at the ulnar and one at the radial styloid process of the wrist. The other two were connected with a wand and placed on the ulna close to the elbow joint. After a static trial, the patient was asked to perform separate movements of elbow flexion/extension, shoulder flexion/extension, and shoulder abduction/adduction to determine the shoulder joint position and the location of the elbow joint axis. Specifically, in these shoulder calibration trials the sternoclavicular joint was considered a cardan joint. Technical coordinate systems for the ulna/forearm, humerus, clavicle, and thorax were not extrapolated by optimization methods as was done for marker clusters. Instead, they were grounded directly on marker trajectories, i.e., the direction vectors between them, using cross-products as demonstrated by Chiari et al..
(Enlarge Image)
Figure 1.
Skeletal model with markers and test person sitting on the chair, prepared with the markers for the 3D motion analysis using the HUX model.
(Enlarge Image)
Figure 2.
Localization of the glenohumeral joint chenter of rotation (GHJC) and measurement of an angle in the ab-/adduction plane using the HUX model.
Maximum Values and ADLs
For flexion/extension and abduction/adduction the corresponding angles between the body's long axis and the humerus were accounted for (thoracohumeral angle). The body's long axis is fixed to the thorax-TF; hence, compensatory movement of the thorax can be monitored and distinguished from shoulder movement. To determine the maximum values, the maximum ROM at flexion/extension, abduction/adduction, and also internal and external rotation was dynamically assessed. Angles of flexion/extension and abduction/adduction were expressed as projection angles relative to the proximal anatomical coordinate system. The maximum rotation, defined by the globe convention, was measured at 90° degrees of arm abduction to avoid the singularities of the convention for the hanging arm/arm in neutral position. For this, the subject sat on a stool and was instructed to move his/her arm to the respective maximum position without moving his torso. The recordings of ADLs contained the following motions: "combing the hair (cmb)", "washing the opposite armpit (wsh)", "tying an apron (aprn)", and "taking a book from a shelf (shlf)". Starting from the seated position the subject was asked to carry out these movements by trying not to move the torso. Original position was the static calibration recording and each movement was conducted three times in a row. We calculated an average maximum of the 3 trial maxima. For "combing" the subject held a comb in his/her hand and was asked to move to the forehead for combing from there to the back of the head and finally to go back to the original position. For "washing the opposite axilla" the subject held a washcloth and was asked to move it to the opposite axilla to implement a typical motion of washing there and to return to the original position. For the motion "tying an apron" the subject was asked to move the hand to the back of the torso and then return to the original position. For "taking the book" a height adjustable shelf was used. The height of the shelf was adjusted at forehead level and the book was positioned at the distance of the respective arm length centered to the test person. The subject was then asked to assume the original position place the book in his/her hand, move back to original position with the book, then to put the book back to the shelf and finally to return to the original position without the book. After extracting the motion data using the vicon software (Vicon 612; Vicon, Lake Forest, USA), all calculations were done using Microsoft Excel 2010 software. Statistical analysis was performed using SPSS Version 16.0 (SPSS Inc., Chicago, IL, USA). Group mean values (MV) and standard deviations (SD) were calculated. P values of <0.05 were considered as significant. The distribution of the data was evaluated by using the Shapiro-Wilk test and the homogeneity of variance was assessed using the Levene test. The angle between the long axis of the humerus and the trunk position was determined. The maximum and the minimum angles and the ROM for each task were monitored. The ROMs of the ADL in each plane were compared pre- and postoperative shoulder joint angles were compared by using the Wilcoxon test. As a second outcome measure, differences among these patients and the controls were examined using a Mann–Whitney U test.