Shoulder Motion Analysis During Codman Pendulum Exercises.

PURPOSE: To quantify shoulder motion during Codman pendulum exercises. METHODS: Shoulder kinematics were analyzed in 17 healthy volunteers using a validated biomechanical model coupling patient-specific imaging and motion capture. Participants were instructed to perform medio-lateral, antero-posterior and circular pendulum exercises. Glenohumeral (GH), scapulothoracic (ST), thoracohumeral (TH) ROM and overall exercise amplitude were calculated for each sequence. Linear regression analyses were carried out to determine association between different components of shoulder motion. RESULTS: Mean overall exercise amplitude was 40.59±11.24° (range, 25.38 to 70.25°) for medio-lateral exercises, 46.5±22.02° (range, 20.68 to 100.24°) for antero-posterior exercises, and 20.28±7.13° (range, 10.9 to 35.49°) for circular exercises. Mean GH and ST involvement remained minimal, ranging from 6.74 to 13.81°, and 1.5° to 5.12°, respectively. There was no significant correlation between overall exercise amplitude and GH (R = 0.31, p = 0.01) or ST ROM (adjusted R2 = 0.57, p < 0.001), but a moderate correlation with TH ROM (R = 0.73, p < 0.001). CONCLUSION: This study demonstrates that Codman pendulum exercises depend mainly on truncal movement and produce very little movement in the GH and ST joints. Although they may be a safe way to promote early general stretching of the upper limb, they may be of limited further use in restoring passive shoulder ROM. CLINICAL RELEVANCE: This study quantifies motion during frequently administered shoulder rehabilitation exercises and shows that they do not produce significant movement in the shoulder. Their use in restoring passive range of motion is thus questionable.

Altered stress induced by partial transection of the infraspinatus tendon leads to perlecan (HSPG2) accumulation in an ovine model of tendinopathy.

Perlecan is a widely distributed, heparan sulphate proteoglycan with roles in the sequestration of FGFs, PDGF, VEGF through which it promotes cell proliferation and matrix production. Perlecan also stabilises extracellular matrices through interaction with a diverse range of matrix components. This study examined the distribution of perlecan in an ovine partial transection tendinopathy model. In normal tendon, perlecan was immunolocalised to small blood vessels in intrafascicular regions in the tendon-bone and muscle-tendon attachments and to linear arrays of oval shaped tenocytes in the tendon mid-region. Partial transection in the mid-tendon region significantly increased perlecan accumulation within the fascicles, in granulation tissue filling the transection site and in the tendon-bone and tendon-muscle attachments. The accumulation of perlecan in the transected tendon and its known roles in matrix stabilisation and cell proliferation indicate possible roles in tendon remodelling and repair. Perlecan domain-1 has been used as a growth factor delivery vehicle for FGF-2, BMP-2 and BMP-7 in regenerative medicine but has yet to be evaluated in infraspinatus tendon repair. A better understanding of perlecan's contributions to pathobiological processes in remodelling tendon may be useful in such regenerative strategies in the future.

Photoelastic comparison of strains in the underlying glenoid with metal-backed and all-polyethylene implants.

An alteration in the stress and strain environment following arthroplasty is believed to lead to bone remodeling, which can trigger implant loosening and subsequent failure. Bone remodeling, while well-studied in hip arthroplasty, has received less attention in total shoulder replacement. This study examines differences in strain states between intact glenoids and following replacement with an uncemented metal backed keeled component and a cemented all polyethylene pegged component with the same articular geometry, using the photoelastic method. Strain measurements were taken in glenoids before and after implantation under 4 loading conditions corresponding to 4 abduction angles: 0 degrees, 30 degrees, 60 degrees, and 90 degrees. Shear strains increased at most locations following reconstruction with both of the implants. Uncemented, keeled metal backed implants produced areas of higher cortical shear strains compared to cemented, all PE pegged implants.

Proteoglycan 4 downregulation in a sheep meniscectomy model of early osteoarthritis.

Osteoarthritis is a disease of multifactorial aetiology characterised by progressive breakdown of articular cartilage. In the early stages of the disease, changes become apparent in the superficial zone of articular cartilage, including fibrillation and fissuring. Normally, a monolayer of lubricating molecules is adsorbed on the surface of cartilage and contributes to the minimal friction and wear properties of synovial joints. Proteoglycan 4 is the lubricating glycoprotein believed to be primarily responsible for this boundary lubrication. Here we have used an established ovine meniscectomy model of osteoarthritis, in which typical degenerative changes are observed in the operated knee joints at three months after surgery, to evaluate alterations in proteoglycan 4 expression and localisation in the early phases of the disease. In normal control joints, proteoglycan 4 was immunolocalised in the superficial zone of cartilage, particularly in those regions of the knee joint covered by a meniscus. After the onset of early osteoarthritis, we demonstrated a loss of cellular proteoglycan 4 immunostaining in degenerative articular cartilage, accompanied by a significant (p < 0.01) decrease in corresponding mRNA levels. Early loss of proteoglycan 4 from the cartilage surface in association with a decrease in its expression by superficial-zone chondrocytes might have a role in the pathogenesis of osteoarthritis.

Regional assessment of articular cartilage gene expression and small proteoglycan metabolism in an animal model of osteoarthritis.

Osteoarthritis (OA), the commonest form of arthritis and a major cause of morbidity, is characterized by progressive degeneration of the articular cartilage. Along with increased production and activation of degradative enzymes, altered synthesis of cartilage matrix molecules and growth factors by resident chondrocytes is believed to play a central role in this pathological process. We used an ovine meniscectomy model of OA to evaluate changes in chondrocyte expression of types I, II and III collagen; aggrecan; the small leucine-rich proteoglycans (SLRPs) biglycan, decorin, lumican and fibromodulin; transforming growth factor-beta; and connective tissue growth factor. Changes were evaluated separately in the medial and lateral tibial plateaux, and were confirmed for selected molecules using immunohistochemistry and Western blotting. Significant changes in mRNA levels were confined to the lateral compartment, where active cartilage degeneration was observed. In this region there was significant upregulation in expession of types I, II and III collagen, aggrecan, biglycan and lumican, concomitant with downregulation of decorin and connective tissue growth factor. The increases in type I and III collagen mRNA were accompanied by increased immunostaining for these proteins in cartilage. The upregulated lumican expression in degenerative cartilage was associated with increased lumican core protein deficient in keratan sulphate side-chains. Furthermore, there was evidence of significant fragmentation of SLRPs in both normal and arthritic tissue, with specific catabolites of biglycan and fibromodulin identified only in the cartilage from meniscectomized joints. This study highlights the focal nature of the degenerative changes that occur in OA cartilage and suggests that altered synthesis and proteolysis of SLRPs may play an important role in cartilage destruction in arthritis.

Should acute anterior dislocations of the shoulder be immobilized in external rotation? A cadaveric study.

The high recurrence rate associated with anterior shoulder dislocations may reflect inadequate healing of a Bankart lesion when the arm is immobilized in internal rotation. The effect of external rotation (ER) of the humerus on the glenoid-labrum contact of Bankart lesions was examined in 10 human cadaveric shoulders. The contact force between the glenoid labrum and the glenoid was measured in 60 degrees of internal rotation, neutral rotation, and 45 degrees of ER in 10 human cadaveric shoulders. No detectable contact force was found with the arm in internal rotation. The contact force increased as the arm passed through neutral rotation and reached a maximum at 45 degrees of ER. The contact force returned to 0 g when the arm was returned to neutral rotation. The mean contact force at 45 degrees of ER was 83.5 g. External rotation significantly increases the labrum-glenoid contact force and may influence the healing of a Bankart lesion.

What is the role of joint replacement surgery?

Now into the fourth decade of widespread clinical acceptance and use, joint replacement surgery has had a major impact on the preservation of physical independence and general health in the ageing population. However, today's data are tomorrow's history. Rather than tell clinicians and patients what they might expect today from yesterday's procedure, this chapter surveys the role of joint replacement in the treatment of degenerative disease, assesses the associated fiscal burden on society and notes the significant gaps in our current knowledge. Strategies and approaches for future study are critically reviewed.

Internal fixation of symptomatic os acromiale: a series of twenty-six cases.

Twenty-six patients who presented to our shoulder service with a symptomatic meso-os acromiale were reviewed. All had been initially treated for impingement symptoms. Nonoperative treatment had failed in all patients. One patient had also undergone an arthroscopic acromioplasty without benefit. The diagnosis of symptomatic os acromiale was made on the basis of radiographs and point tenderness over the acromion coupled with signs of rotator cuff pathology. We assessed these patients after treatment by internal fixation and bone grafting. Fixation was achieved with either K-wires or screws and tension banding with either wire or suture. Fifteen patients had associated rotator cuff tears. The clinical and radiologic results are reported. The rate of union was 96% (25/26), and 24 of 26 patients (92%) were satisfied with their results. The mean time to union was 4 months. There were two postoperative fractures. Eight patients (thirty-one percent) had postoperative pain that was subsequently relieved by wire or screw removal. Seventeen patients had concomitant rotator cuff tears. Eleven cuff tears were repaired, and six were irreparable. One of these six was extensively debrided. We conclude that open reduction-internal fixation of the symptomatic meso-acromion yields satisfactory results, and with the exception of hardware discomfort necessitating removal, minimal complications arise in the majority of cases.

Regional antibiotic prophylaxis in elbow surgery.

In this study we describe a technique for the delivery of regional antibiotic prophylaxis in patients undergoing elbow surgery and compare tissue antibiotic concentrations achieved by this technique with those achieved by standard systemic intravenous prophylaxis. We collected bone and fat samples from patients undergoing elective elbow surgery who had received regional antibiotic prophylaxis and measured the tissue antibiotic concentration. For comparison, we measured the antibiotic concentration in bone and fat samples taken from patients undergoing elective shoulder surgery who had received systemic prophylaxis. Mean tissue antibiotic concentrations were significantly higher in the regional antibiotic group (bone, 1484 microg/g vs 35.8 microg/g; fat, 1422.7 microg/g vs 10.7 microg/g; P <.05). No adverse effects were encountered with regional antibiotic delivery. The delivery of regional antibiotic prophylaxis in elbow surgery achieves higher tissue antibiotic concentrations than those achieved with standard systemic delivery. This technique may help reduce the risk of perioperative infection in elbow surgery.

Biomechanical analysis of five fixation techniques used in glenohumeral arthrodesis.

BACKGROUND: The purpose of the present study is to compare five fixation techniques in shoulder fusion. The most common complications resulting from shoulder fusion, non-union and unacceptable arm position, might reflect a failure to achieve rigid fixation during the surgical procedure. METHODS: Twenty-five shoulder fusions were carried out on human cadaveric specimens using the following techniques: screw fixation, external fixation, external fixation supplemented with screw fixation, single plate fixation and double plate fixation. Each specimen was tested on a servohydraulic machine to determine stiffness. RESULTS: There was a statistically significant difference in bending and torsional stiffness between all five fixation techniques. Normalized bending (B) and torsional stiffness (T), in descending order, were: double plate (B = 1.00, T = 1.00), single plate (B = 0.77, T = 0.89), external fixation with screws (B = 0.68, T = 0.74), external fixation alone (B = 0.40, T = 0.53), and screws alone (B = 0.13, T = 0.26). CONCLUSION: The risk of the most common complications resulting from shoulder fusion might be minimized if these biomechanical findings are applied to surgical decision making.

Role of community diagnostic ultrasound examination in the diagnosis of full-thickness rotator cuff tears.

BACKGROUND: Diagnostic ultrasound examination has become the most commonly used investigation in Australia for diagnosing rotator cuff tears. The authors felt that the results of such investigations were often inaccurate in their clinical practices. METHODS: The diagnostic ultrasound findings in 336 cases were compared to arthrography, and in 225 cases findings at surgery. RESULTS: A very poor accuracy rate of 0.38 was found for diagnostic ultrasound examination. The sensitivity was 0.24 and specificity was 0.61. CONCLUSIONS: Extreme caution is recommended in the use of diagnostic ultrasound, as currently practised in a general community setting, in diagnosing full-thickness rotator cuff tears.

Outcome of rotator cuff repair.

From 710 consecutive open rotator cuff repairs by a single surgeon, the results of 667 were available for detailed analysis. Patient-assessed outcomes and the ability to perform specific activities of daily living, employment, and recreation were correlated with independent nonstructural variables including age, sex, workers' compensation status, and revision surgery status. The study shows that patient self-assessment of satisfaction is very high, with 87.5% of all respondents pleased overall. Detailed assessment is provided of certain subgroups that are more likely to report worse results after surgery. These include patients on workers' compensation, those undergoing revision surgery, and those younger than 55 years of age. Information presented here may be useful during preoperative counseling for rotator cuff repairs, to ensure realistic patient expectations.

Structural factors affecting the outcome of rotator cuff repair.

A retrospective review of 667 rotator cuff tears analyzed structural factors that might influence outcome. Tear size was not found to be an indicator of likely patient satisfaction, and concomitant rupture of the biceps tendon did not prejudice the outcome. In this first reported study of the influences of delamination disease and the surgical manner in which it is treated, it was found that at least when treated by interlaminar curettage before repair, cuff delamination did not appear to prejudice patient satisfaction. The study also found that tendon-to-tendon and tendon-to-bone repairs fared equally well, as judged by the criteria used here.