- Email: [email protected]
The reliability of fixed versus handheld dynamometer for shoulder strength testing
e34
2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
when compared with normal data, contrasting with postrehabilitation data, where variability extended beyond the levels displayed in the control group. Conclusions: Based on functional outcomes, this study provides support for conservative rehabilitation in MDI. The dynamic systems theory would suggest that the broader spectrum of EMG variability identified could be associated with the improved function output. Given the associated structural deficits in MDI, it is potentially unreasonable to expect MDI subjects to replicate the activation patterns previously noted in an asymptomatic population. Allowing patients with MDI to move with more than one motor strategy disperses soft tissue loads and diminishes repetitive microtrauma. Clinically, the notion of motor variability could be beneficial when establishing a functional rehabilitation program. Future larger scale EMG studies are needed to generate a more sound understanding of the dynamic systems approach and the relationship of variability with optimal functionality.
(external rotators) to prevent this anterior translation would be counterproductive to the generation of maximum internal rotation torque required during the acceleration phase. Contraction of latissimus dorsi, on the other hand, could prevent anterior translation of the humeral head during the acceleration phase of pitching while contributing to the generation of internal rotation torque. Significantly lower activity in latissimus dorsi would, therefore, result in an inability to produce enough counterbalancing force to prevent pectoralis major and subscapularis from producing some anterior humeral head translation resulting in the symptoms of anterior shoulder instability. These findings have implications for the understanding and rehabilitation of throwers with shoulder instability.
doi:10.1016/j.jsams.2010.10.532
The reliability of fixed versus handheld dynamometer for shoulder strength testing
72
N. Beshay 1,2,∗ , P. Lam 1,2 , G. Murrell 1,2
Subscapularis does not stabilize the glenohumeral joint during throwing C. Boettcher ∗ , K. Ginn, I. Cathers The University of Sydney, Australia During throwing the rotator cuff muscles are considered to function as stabilizers of the shoulder joint as well as accelerators and decelerators of the humerus. However, a recent study examining isometric shoulder rotation in an abducted position indicates that the rotator cuff muscles are unlikely to be performing a stabilizer function in this position. Furthermore, research from this same laboratory has shown that co-contraction of the rotator cuff is not necessary to provide dynamic shoulder stability in all planes of movement. During flexion and extension the rotator cuff muscles contract reciprocally, with infraspinatus and supraspinatus active during flexion and subscapularis active during extension, to prevent anterior and posterior displacement of the humeral head respectively. Past EMG research comparing shoulder muscle activity in normal pitchers and pitchers with anterior instability during the acceleration phase of the pitch demonstrated significantly lower activity in latissimus dorsi in the unstable pitchers with no significant difference in posterior cuff (infraspinatus and supraspinatus) activity levels between normal and unstable groups. These authors were unable to provide a clear explanation for the instability in light of this altered shoulder muscle activity. It is proposed from the results of our recent research that the reduced latissimus dorsi activity may be the cause of anterior instability. That is, both subscapularis and pectoralis major may potentially cause anterior translation of the humeral head during the acceleration phase. Activity in the posterior cuff
doi:10.1016/j.jsams.2010.10.533 73
1 St
George Hospital Orthopaedic Research Institute, Australia 2 The University of New South Wales, Australia Background: Reliable measurements of shoulder strength are important in assessing rotator cuff integrity. Hand-held dynamometry (HHD) is more objective and reliable than the traditional manual muscle test. However, the reliability of HHD may be limited by examiner strength. A fixed strength assessment device may offer a solution to this potential problem. Aim: To determine if a fixed strength assessment device (made by the Orthopaedic Research Institute) is more reliable than HHD when measuring the strength of five shoulder movements (internal rotation, external rotation, abduction-supraspinatus, lift-off and adduction). Materials and methods: Twelve asymptomatic and 11 symptomatic subjects participated in the intra-rater reliability assessment. For each subject, the strength of five shoulder movements was tested three times using HHD and three times using the fixed device by the same examiner. Eleven asymptomatic subjects and 10 symptomatic subjects participated in the inter-rater reliability assessment. Each of three examiners tested the shoulder strength of each subject, once using HHD and once using the fixed device. Intraclass correlation coefficients (ICCs) were calculated to assess reliability and Bland-Altman plots were constructed to identify any associations between subject strength and reliability of measurements. Results: Average ICC values for intra-rater testing for all five movements were 0.97 for asymptomatic subjects and 0.94 for symptomatic subjects using the fixed strength device. When tested with HHD, average ICC values were 0.95 and 0.94 respectively. Average ICC values during inter-rater testing for all five movements was 0.93 for asymptomatic subjects
2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
e35
and 0.92 for symptomatic subjects using the fix strength device and 0.89 and 0.93 for HHD. The inter-rater reliability of HHD dropped to 0.83 when the subject’s supraspinatus strength was greater than 100 N. Conclusion: HHD is a reliable method of measuring shoulder strength in the clinical setting. However, when several examiners are testing the supraspinatus strength of stronger subjects, stabilising the dynamometer provides more reliable results.
der and may help explain the often severe pain in frozen shoulder.
doi:10.1016/j.jsams.2010.10.534
D. Biggs ∗ , B. Haviv, E. Dolev, M. Haber, L. Mayo
74
Central West Orthopaedics and Sports Injuries, Australia
Expression of neuronal markers in frozen shoulder C. Xu 1 , F. Bonar 2 , G. Murrell 1,∗ 1 St
George Hospital Orthopaedic Research Institute, Australia 2 Douglas Hanley Moire Pathology, Australia Frozen shoulder is a condition characterized by pain and loss of motion of the shoulder. It was first described by Codman in 1934, however the aetiology of this disease remains unclear and our understanding of the pathogenesis, and why it is so painful is undetermined. The aim of this study was to evaluate the innervation pattern of the synovium and capsule of frozen shoulder. Methods: Following ethics approval shoulder capsular samples were collected from patients undergoing arthroscopic shoulder capsular release for frozen shoulder (n = 8). Control capsular samples were collected from patients undergoing rotator cuff repair (n = 10). Clinical symptoms were recorded. Tissue samples were analysed using histological staining, and immunohistochemical analysis using antibodies against a general nerve marker (protein gene product 9.5, PGP9.5), a nerve growth marker (growth associated protein 43, GAP43), a nerve growth factor receptor p75, an endothelial cell marker (CD34). Results: The capsular tissue of patients with frozen shoulder was red and thick at arthroscopy. Morphological analysis showed synovial and subsynovial oedema with hypercellularity and hypervascularity. The increased vascularity was confirmed by strongly positive CD34 immunostaining. Increased expression of nerve growth factor receptor p75 was also found in frozen shoulder samples compared to controls. The presence of PGP9.5-positive and GAP43-positive nerves was significantly higher in frozen shoulder samples (2.8 ± 0.2 and 2.4 ± 0.4 per field) than in the controls (1.6 ± 0.3 and 1.3 ± 0.3 per field; p < 0.01 and p < 0.05). Conclusion: To our knowledge this is the first time significantly increased expression of nerve growth factor receptor and new nerve fibres have been found in the shoulder capsular tissue of patients with frozen shoulder compared with those without a frozen shoulder. The increased expression of nerve growth factor receptor and new nerves in the capsular tissue suggest that the in-growth of new nerves to the shoulder capsule is an important event in the pathogenesis of frozen shoul-
doi:10.1016/j.jsams.2010.10.535 75 Arthroscopic rotator cuff repair: Clinical outcome of 606 patients
During the last decade arthroscopic repair has evolved to become common practice in the surgical treatment of symptomatic rotator cuff tendon tears. This paper reports the results of a consecutive series of patients who underwent arthroscopic rotator cuff repair surgery. All patients were independently assessed pre and post operatively utilizing the UCLA scoring system. All procedures were performed by a single surgeon, with a minimum of one year follow-up. Operative details were noted, including patient age, tear size, type of repair performed and concomitant procedures performed. Overall, 87% of patients had a good-excellent result. The results were found to be independent of tear size, tear configuration and concomitant procedures performed. This prospective study is one of the largest series of arthroscopic rotator cuff repairs reported. According to our results, 87% of patients who underwent arthroscopic rotator cuff repair have maintained good clinical outcomes up to 8 years after surgery. doi:10.1016/j.jsams.2010.10.536 76 A comparative study of arthroscopic and open rotator cuff repair outcomes of 400 patients followed for two years or longer J. Walton ∗ , G. Murrell St George Hospital Orthopaedic Research Institute, Australia Introduction: Open surgery is regarded as the gold standard for RCR although arthroscopic surgery also both provides excellent results for patients in need of rotator cuff repair (RCR). Arthroscopic RCR is less invasive but is thought to require a longer operative time and to result in less secure repairs more prone to re-tear. We performed an outcomes study of 400 patients repaired by a single surgeon – 200 with open RCR or 200 with arthroscopic RCR – to test the hypothesis that open RCR provides superior outcomes to arthroscopic RCR. Methods: For this study, patients attended clinic pre-operatively and on four post-operative occasions, completing a pain and function questionnaire and receiving a systematic shoulder assess-
2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
when compared with normal data, contrasting with postrehabilitation data, where variability extended beyond the levels displayed in the control group. Conclusions: Based on functional outcomes, this study provides support for conservative rehabilitation in MDI. The dynamic systems theory would suggest that the broader spectrum of EMG variability identified could be associated with the improved function output. Given the associated structural deficits in MDI, it is potentially unreasonable to expect MDI subjects to replicate the activation patterns previously noted in an asymptomatic population. Allowing patients with MDI to move with more than one motor strategy disperses soft tissue loads and diminishes repetitive microtrauma. Clinically, the notion of motor variability could be beneficial when establishing a functional rehabilitation program. Future larger scale EMG studies are needed to generate a more sound understanding of the dynamic systems approach and the relationship of variability with optimal functionality.
(external rotators) to prevent this anterior translation would be counterproductive to the generation of maximum internal rotation torque required during the acceleration phase. Contraction of latissimus dorsi, on the other hand, could prevent anterior translation of the humeral head during the acceleration phase of pitching while contributing to the generation of internal rotation torque. Significantly lower activity in latissimus dorsi would, therefore, result in an inability to produce enough counterbalancing force to prevent pectoralis major and subscapularis from producing some anterior humeral head translation resulting in the symptoms of anterior shoulder instability. These findings have implications for the understanding and rehabilitation of throwers with shoulder instability.
doi:10.1016/j.jsams.2010.10.532
The reliability of fixed versus handheld dynamometer for shoulder strength testing
72
N. Beshay 1,2,∗ , P. Lam 1,2 , G. Murrell 1,2
Subscapularis does not stabilize the glenohumeral joint during throwing C. Boettcher ∗ , K. Ginn, I. Cathers The University of Sydney, Australia During throwing the rotator cuff muscles are considered to function as stabilizers of the shoulder joint as well as accelerators and decelerators of the humerus. However, a recent study examining isometric shoulder rotation in an abducted position indicates that the rotator cuff muscles are unlikely to be performing a stabilizer function in this position. Furthermore, research from this same laboratory has shown that co-contraction of the rotator cuff is not necessary to provide dynamic shoulder stability in all planes of movement. During flexion and extension the rotator cuff muscles contract reciprocally, with infraspinatus and supraspinatus active during flexion and subscapularis active during extension, to prevent anterior and posterior displacement of the humeral head respectively. Past EMG research comparing shoulder muscle activity in normal pitchers and pitchers with anterior instability during the acceleration phase of the pitch demonstrated significantly lower activity in latissimus dorsi in the unstable pitchers with no significant difference in posterior cuff (infraspinatus and supraspinatus) activity levels between normal and unstable groups. These authors were unable to provide a clear explanation for the instability in light of this altered shoulder muscle activity. It is proposed from the results of our recent research that the reduced latissimus dorsi activity may be the cause of anterior instability. That is, both subscapularis and pectoralis major may potentially cause anterior translation of the humeral head during the acceleration phase. Activity in the posterior cuff
doi:10.1016/j.jsams.2010.10.533 73
1 St
George Hospital Orthopaedic Research Institute, Australia 2 The University of New South Wales, Australia Background: Reliable measurements of shoulder strength are important in assessing rotator cuff integrity. Hand-held dynamometry (HHD) is more objective and reliable than the traditional manual muscle test. However, the reliability of HHD may be limited by examiner strength. A fixed strength assessment device may offer a solution to this potential problem. Aim: To determine if a fixed strength assessment device (made by the Orthopaedic Research Institute) is more reliable than HHD when measuring the strength of five shoulder movements (internal rotation, external rotation, abduction-supraspinatus, lift-off and adduction). Materials and methods: Twelve asymptomatic and 11 symptomatic subjects participated in the intra-rater reliability assessment. For each subject, the strength of five shoulder movements was tested three times using HHD and three times using the fixed device by the same examiner. Eleven asymptomatic subjects and 10 symptomatic subjects participated in the inter-rater reliability assessment. Each of three examiners tested the shoulder strength of each subject, once using HHD and once using the fixed device. Intraclass correlation coefficients (ICCs) were calculated to assess reliability and Bland-Altman plots were constructed to identify any associations between subject strength and reliability of measurements. Results: Average ICC values for intra-rater testing for all five movements were 0.97 for asymptomatic subjects and 0.94 for symptomatic subjects using the fixed strength device. When tested with HHD, average ICC values were 0.95 and 0.94 respectively. Average ICC values during inter-rater testing for all five movements was 0.93 for asymptomatic subjects
2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
e35
and 0.92 for symptomatic subjects using the fix strength device and 0.89 and 0.93 for HHD. The inter-rater reliability of HHD dropped to 0.83 when the subject’s supraspinatus strength was greater than 100 N. Conclusion: HHD is a reliable method of measuring shoulder strength in the clinical setting. However, when several examiners are testing the supraspinatus strength of stronger subjects, stabilising the dynamometer provides more reliable results.
der and may help explain the often severe pain in frozen shoulder.
doi:10.1016/j.jsams.2010.10.534
D. Biggs ∗ , B. Haviv, E. Dolev, M. Haber, L. Mayo
74
Central West Orthopaedics and Sports Injuries, Australia
Expression of neuronal markers in frozen shoulder C. Xu 1 , F. Bonar 2 , G. Murrell 1,∗ 1 St
George Hospital Orthopaedic Research Institute, Australia 2 Douglas Hanley Moire Pathology, Australia Frozen shoulder is a condition characterized by pain and loss of motion of the shoulder. It was first described by Codman in 1934, however the aetiology of this disease remains unclear and our understanding of the pathogenesis, and why it is so painful is undetermined. The aim of this study was to evaluate the innervation pattern of the synovium and capsule of frozen shoulder. Methods: Following ethics approval shoulder capsular samples were collected from patients undergoing arthroscopic shoulder capsular release for frozen shoulder (n = 8). Control capsular samples were collected from patients undergoing rotator cuff repair (n = 10). Clinical symptoms were recorded. Tissue samples were analysed using histological staining, and immunohistochemical analysis using antibodies against a general nerve marker (protein gene product 9.5, PGP9.5), a nerve growth marker (growth associated protein 43, GAP43), a nerve growth factor receptor p75, an endothelial cell marker (CD34). Results: The capsular tissue of patients with frozen shoulder was red and thick at arthroscopy. Morphological analysis showed synovial and subsynovial oedema with hypercellularity and hypervascularity. The increased vascularity was confirmed by strongly positive CD34 immunostaining. Increased expression of nerve growth factor receptor p75 was also found in frozen shoulder samples compared to controls. The presence of PGP9.5-positive and GAP43-positive nerves was significantly higher in frozen shoulder samples (2.8 ± 0.2 and 2.4 ± 0.4 per field) than in the controls (1.6 ± 0.3 and 1.3 ± 0.3 per field; p < 0.01 and p < 0.05). Conclusion: To our knowledge this is the first time significantly increased expression of nerve growth factor receptor and new nerve fibres have been found in the shoulder capsular tissue of patients with frozen shoulder compared with those without a frozen shoulder. The increased expression of nerve growth factor receptor and new nerves in the capsular tissue suggest that the in-growth of new nerves to the shoulder capsule is an important event in the pathogenesis of frozen shoul-
doi:10.1016/j.jsams.2010.10.535 75 Arthroscopic rotator cuff repair: Clinical outcome of 606 patients
During the last decade arthroscopic repair has evolved to become common practice in the surgical treatment of symptomatic rotator cuff tendon tears. This paper reports the results of a consecutive series of patients who underwent arthroscopic rotator cuff repair surgery. All patients were independently assessed pre and post operatively utilizing the UCLA scoring system. All procedures were performed by a single surgeon, with a minimum of one year follow-up. Operative details were noted, including patient age, tear size, type of repair performed and concomitant procedures performed. Overall, 87% of patients had a good-excellent result. The results were found to be independent of tear size, tear configuration and concomitant procedures performed. This prospective study is one of the largest series of arthroscopic rotator cuff repairs reported. According to our results, 87% of patients who underwent arthroscopic rotator cuff repair have maintained good clinical outcomes up to 8 years after surgery. doi:10.1016/j.jsams.2010.10.536 76 A comparative study of arthroscopic and open rotator cuff repair outcomes of 400 patients followed for two years or longer J. Walton ∗ , G. Murrell St George Hospital Orthopaedic Research Institute, Australia Introduction: Open surgery is regarded as the gold standard for RCR although arthroscopic surgery also both provides excellent results for patients in need of rotator cuff repair (RCR). Arthroscopic RCR is less invasive but is thought to require a longer operative time and to result in less secure repairs more prone to re-tear. We performed an outcomes study of 400 patients repaired by a single surgeon – 200 with open RCR or 200 with arthroscopic RCR – to test the hypothesis that open RCR provides superior outcomes to arthroscopic RCR. Methods: For this study, patients attended clinic pre-operatively and on four post-operative occasions, completing a pain and function questionnaire and receiving a systematic shoulder assess-