Massive irreparable rotator cuff tears: how to rebalance the cuff-deficient shoulder.

In its natural state, the shoulder is unbalanced in both the vertical and horizontal planes because the deltoid is stronger than the rotator cuff muscles and the internal rotator muscles are stronger than the external rotator muscles. With aging, this muscle imbalance can become worse, leading to tendon wear, irreversible fatty infiltration of the rotator cuff muscles, and upward migration of the humeral head. Most shoulders with tendon wear are functional and asymptomatic. A traumatic event (such as a fall onto the upper limb) can lead to rotator cuff tearing and a shoulder that becomes symptomatic and nonfunctional. Symptomatic massive irreparable rotator cuff tears present in one of four recognizable patterns depending on the muscular imbalance that occurs and the symptoms that are present: painful loss of active elevation, with conserved muscle balance; isolated loss of active elevation, with loss of vertical muscle balance; isolated loss of external rotation, with loss of horizontal muscle balance; and combined loss of elevation and external rotation, with loss of vertical and horizontal muscle balance. Assessing the plane of shoulder muscle imbalance is a key feature in the decision-making process. Classifying and understanding these tears allows surgeons to select the correct treatment (conservative measures, arthroscopic techniques, reverse shoulder arthroplasty, or tendon transfers) to restore shoulder balance and function.

Specialisation of extracellular matrix for function in tendons and ligaments.

Tendons and ligaments are similar structures in terms of their composition, organisation and mechanical properties. The distinction between them stems from their anatomical location; tendons form a link between muscle and bone while ligaments link bones to bones. A range of overlapping functions can be assigned to tendon and ligaments and each structure has specific mechanical properties which appear to be suited for particular in vivo function. The extracellular matrix in tendon and ligament varies in accordance with function, providing appropriate mechanical properties. The most useful framework in which to consider extracellular matrix differences therefore is that of function rather than anatomical location. In this review we discuss what is known about the relationship between functional requirements, structural properties from molecular to gross level, cellular gene expression and matrix turnover. The relevance of this information is considered by reviewing clinical aspects of tendon and ligament repair and reconstructive procedures.

Revision surgery of reverse shoulder arthroplasty.

BACKGROUND: There is limited knowledge regarding revision of reverse shoulder arthroplasty (RSA). This study assesses reasons for failure in RSA and evaluates the outcomes of revision RSA. MATERIALS AND METHODS: Between 1997 and 2009, 37 patients with RSA had revision surgery. Clinical and radiologic examinations performed preoperatively and at 3 months, at 6 months, and then annually postoperatively were analyzed retrospectively. Patients were reviewed with a minimum 2-year follow-up. RESULTS: The most common causes for RSA revision were prosthetic instability (48%); humeral loosening, derotation, or fracture (21%); and infection (19%). Only 2 patients (3%) had to be reoperated on for glenoid loosening. More than 1 re-intervention was performed in 11 patients (30%) because of recurrence of the same complication or appearance of a new complication. Underestimation of humeral shortening and excessive medialization were common causes of recurrent prosthetic instability. Proximal humeral bone loss was found to be a cause for humeral loosening or derotation. Previous surgery was found as a potential cause of low-grade infection. At a mean follow-up of 34 months, 32 patients (86%) had retained the RSA whereas 2 patients (6%) had undergone conversion to humeral hemiarthroplasty and 3 (8%) to a resection arthroplasty. The mean Constant score in patients who retained the RSA increased from 19 points before revision to 47 points at last follow-up (P < .001). CONCLUSIONS: Even if revision may lead to several procedures in the same patient, preservation or replacement of the RSA is largely possible, allowing for a functional shoulder. Full-length scaled radiographs of both humeri are recommended to properly assess humeral shortening and excessive medialization before revision.

Reversed shoulder arthroplasty with modified L'Episcopo for combined loss of active elevation and external rotation.

HYPOTHESIS: In patients with a rotator cuff-deficient shoulder, a combined loss of active elevation and external rotation (CLEER) can occur when both the infraspinatus and teres minor muscles are absent. A reverse shoulder arthroplasty (RSA) can restore active elevation in these patients but cannot restore active external rotation because there are no other external rotator cuff muscles. We hypothesized that a modified L'Episcopo procedure (latissimus dorsi [LD] and teres major [TM] transfer) with a simultaneous RSA would restore shoulder function and activities of daily living (ADLs). MATERIALS AND METHODS: Seventeen consecutive patients (mean age, 71 years) with CLEER underwent this combined procedure through a single deltopectoral approach and were prospectively monitored for at least 12 months. All patients had severe cuff tear arthropathy and advanced atrophy or fatty infiltration of the infraspinatus/teres minor muscles on preoperative magnetic resonance imaging or computed tomography scans. The patients were immobilized in 30 degrees of abduction and external rotation for 6 weeks postoperatively before starting rehabilitation. RESULTS: Mean active elevation increased from 74 degrees preoperatively to 149 degrees postoperatively (+75 degrees ), and external rotation increased from -21 degrees to 13 degrees (+34 degrees ). Patient satisfaction, subjective shoulder value, Constant-Murley scores and ADLs all improved significantly. DISCUSSION & CONCLUSIONS: In patients with CLEER, the association of RSA with LD/TM transfer restores active elevation and external rotation. The combined procedure, performed in the same session through a deltopectoral approach, is indicated in a selected subgroup of patients with a rotator cuff-deficient shoulder and an absent or atrophied infraspinatus/teres minor muscles. Our technique is easier to perform than the two-incision procedure and appears to avoid problems such as extensive scarring, adhesions and axillary nerve lesions. Transferring both the LD and TM, rather than the LD alone, results in better active external rotation.

Tendons and ligaments are anatomically distinct but overlap in molecular and morphological features--a comparative study in an ovine model.

Tendons and ligaments are similar in composition but differ in function. Simple anatomical definitions do not reflect the fact individual tendons and ligaments have unique properties due to their adaptation to a specific role. The patellar tendon is a structure of particular clinical interest. A null hypothesis was declared stating that the patellar tendon is not significantly different in terms of matrix composition and collagen fibril diameter to other tendons. The lateral and medial collateral ligaments (LCL, MCL), anterior and posterior cruciate ligaments (ACL, PCL), together with the long digital extensor, superficial digital extensor, and patellar tendons (LDET, SDFT, PT) were harvested from three cadaveric ovine hindlimbs. The extracellular matrix was assessed in terms of water, collagen, and total sulphated glycosaminoglycan (GAG) content. The organization of the collagen component was determined by an ultrastructural analysis of collagen fibril diameter distributions, together with values for the collagen fibril index (CFI) and mass-average diameter (MAD). There were significant differences between ligaments and tendons. The PT had a bimodal collagen fibril diameter distribution with CFI 72.9%, MAD 202 nm, water content 53.1%, GAG content 2.3 microg/mg, and collagen content 73.7%, which was not significantly different from the other tendons. The results of this study support the null hypothesis suggesting that the patellar tendon is similar to other tendons and demonstrate that tendons have different characteristics to ligaments.