The rotator cuff-deficient arthritic shoulder: diagnosis and surgical management

The influence of shoulder arthrodesis on the function of the upper limb in adult patients after a brachial plexus injury: a systematic literature review with elements of meta-analysis

Based on the literature, 294 shoulder arthrodeses after brachial plexus injury in adults were assessed, mostly male; the mean age of the patients was 33 years, and the mean follow-up time was 5.5 years. The most common cause of injury was a traffic accident, especially on a motorcycle.

Arthrodesis position ranged from 15 to 40 degrees of flexion, 15 to 60 degrees of abduction, and 0 to 50 degrees of internal rotation with the predominance of position by the 30-30-30 rule. Plates, screws, and external fixation were used for stabilization. The complication rate was at the level of 28%, the most common complication being delayed union or nonunion.

Active movements of flexion and abduction averaged 61 and 56 degrees, respectively, while reaching the hand to the mouth, front pocket, and buttock was feasible for 69%, 71%, and 38%, respectively, after surgery. Shoulder pain was present in 77% of patients, and 28% experienced no relevant pain reduction after surgery. The subjective satisfaction rate was 82% based on significant improvement and satisfaction reported by patients after arthrodesis.

Arthrodesis of the shoulder, in adult patients after brachial plexus palsy, can reduce shoulder pain, increase stability, and result in a range of motion that increases the possibility of carrying out everyday activities. This affects the high level of subjective patient satisfaction after surgery.

Cite this article: EFORT Open Rev 2021;6:797-807. DOI: 10.1302/2058-5241.6.200114

Reverse shoulder arthroplasty: Functional results in rotator cuff arthropathy

Objective  To evaluate the functional results of patients submitted to reverse shoulder arthroplasty for the treatment of rotator cuff arthropathy refractory to conservative treatment. Methods  A retrospective study of 20 patients (21 shoulders), 17 women (81%) and 3 men (19%), underwent a reverse shoulder arthroplasty between October 2012 and September 2017, for a rotator cuff arthropathy treatment, operated by a single surgeon in a single center. The patients were assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) score, the Short-Form (36) Health Survey (SF-36), the visual analogue scale (VAS) of pain rating, and the University of California - Los Angeles (UCLA) score. The mean age at surgery was of 66 years old (range: 55 to 83 years old). The duration of symptoms before surgery was of ∼ 2.5 years (range: 12 months to 6 years). The mean follow-up was of 42.4 months (range: 19 to 56.7 months). Results  The mean postoperative scores were 18.2 points in DASH; 2 points in EVA, of which 16 (77%) corresponded to mild pain, 4 (18%) to moderate pain, and 1 (5%) to severe pain; 29 points in UCLA, of which 6 patients presented a regular result (28%), 10 patients a good result (48%), and 5 patients an excellent result (24%); and 63 points in the SF-36. The complications were four cases of notching, one case of acromial fracture due to stress, and one case of postoperative infection. Conclusions  Reverse arthroplasty of the shoulder presents good functional results in the evaluated scores, providing a significant improvement in the quality of life of the patients.

Anatomical and biomechanical framework for shoulder arthroplasty rehabilitation

This article provides an anatomical and biomechanical framework for the postoperative management and progression of treatment for shoulder arthroplasty. The clinical relevance of normal shoulder anatomy, biomechanics, and pathomechanics related to this surgery is emphasized to provide the reader with an understanding of the rationale for treatment. We review the rehabilitation implications of surgical indications and technique for both traditional total shoulder arthroplasty and reverse total shoulder arthroplasty procedures with an emphasis on biomechanical considerations. Relevant factors that affect rehabilitation outcomes are discussed along with supporting evidence from the literature. Principles to guide and progress treatment are highlighted with a discussion on return to sports with the ultimate objective of providing a comprehensive approach for successful rehabilitation.

Influence of rotator cuff tears on glenohumeral stability during abduction tasks

One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1628-1635, 2016.

Evaluation of the acromiohumeral distance by means of magnetic resonance imaging umerus

Objective

To demonstrate the relationship between the size, degree of retraction and topography of rotator cuff injuries and the degree of rise of the humeral head, and to evaluate the influence of gravity, using magnetic resonance imaging (MRI).

Methods

We evaluated 181 shoulder MRIs from 160 patients aged over 45 years, between November 2013 and July 2014. The patients were divided into two groups: one control (no lesion or partial damage to the rotator cuff); and the other with complete tears of the rotator cuff. We measured the acromiohumeral distance in the sagittal plane, and established the shortest distance between the apex of the head and the acromion.

Results

In this study, 96 examinations on female patients (53.04%) and 58 on male patients (46.96%) were evaluated. The mean age was 63.27 years: in the control group, 61.46; and in the group with injuries, 65.19. From analysis on the measurements of the subacromial space, we observed significantly higher values in the control group (7.71 mm) than in the group with injuries (6.99). In comparing the control group with some specific subgroup, i.e. posterosuperior (6.77), anteroposterior-superior (4.16) and retraction Patte III (5.01), we confirmed the importance of topography and degree of retraction in relation to the rise of the humeral head.

Conclusion

The rise of the humeral head was directly related to the size, degree of retraction and topography of the rotator cuff injuries, with greater degrees of rise in cases of superior and posterior lesions and anteroposterior-superior (massive) lesions. The assessment using MRI was not influenced by the force of gravity.

Low-term results from non-conventional partial arthroplasty for treating rotator cuff arthroplasthy

OBJECTIVE

To evaluate the evolution of the functional results from CTA(®) hemiarthroplasty for surgically treating degenerative arthroplathy of the rotator cuff, with a mean follow-up of 5.4 years.

METHODS

Eighteen patients who underwent CTA(®) partial arthroplasty to treat degenerative arthroplathy of the rotator cuff between April 2007 and June 2009 were reevaluated, with minimum and mean follow-ups of 4.6 years and 5.4 years, respectively. Pre and postoperative parameters for functionality and patient satisfaction were used (functional scale of the University of California in Los Angeles, UCLA). All the patients underwent prior conservative treatment for 6 months and underwent surgical treatment because of the absence of satisfactory results. Patients were excluded if they presented any of the following: previous shoulder surgery; pseudoparalysis; insufficiency of the coracoacromial arch (type 2 B in Seebauer's classification); neurological lesions; or insufficiency of the deltoid muscle and the subscapularis muscle.

RESULTS

With a mean follow-up of 5.4 years, 14 patients considered that they were satisfied with the surgery (78%); the mean range of joint motion for active elevation improved from 55.8° before the operation to 82.0° after the operation; the mean external rotation improved from 18.9° before the operation to 27.3° after the operation; and the mean medial rotation remained at the level of the third lumbar vertebra. The mean UCLA score after the mean follow-up of 5.4 years was 23.94 and this was an improvement in comparison with the preoperative mean and the mean 1 year after the operation.

CONCLUSION

The functional results from CTA(®) hemiarthroplasty for treating rotator cuff arthroplasty in selected patients remained satisfactory after a mean follow-up of 5.4 years.

Long-term results of shoulder hemiarthroplasty in patients with rheumatoid arthritis

Rheumatoid arthritis affecting the shoulder is typically associated with destruction of the glenohumeral joint and rotator cuff impairment, which can result in severe glenoid erosion. Following hemiarthroplasty, severe glenoid erosion has also frequently been observed. The authors' aim was to retrospectively evaluate the outcome of cemented shoulder hemiarthroplasty in patients with rheumatoid arthritis. The authors performed 45 cemented hemiarthroplasties in 36 patients with rheumatoid arthritis involving the shoulder as well as associated rotator cuff compromise between 1995 and 2008. All patients were analyzed radiologically and clinically using patient-reported outcome measures. Mean±SD visual analog pain scale score was 3±2. Mean±SD Constant score was 55±16. Mean±SD validated Dutch version of the Disabilities of the Arm Shoulder and Hand (DASH) score was 42±19. No radiograph showed loosening of the implant at follow-up. One patient needed an arthrotomy and capsulotomy because of persistent pain and limited range of motion. Tissue cultures taken during this second operation were negative for infection. No major revision surgery was necessary within the follow-up period. Cemented hemiarthroplasty is a viable treatment option for glenohumeral arthritis in patients with rheumatoid arthritis. Long-term results show acceptable results and low complication rates in this case series for this specific group. A randomized, controlled trial comparing hemiarthroplasty, total shoulder arthroplasty, and reverse shoulder arthroplasty is necessary to draw definite conclusions in this specific patient population.

Reverse shoulder arthroplasty

The reverse shoulder arthroplasty is considered to be one of the most significant technological advancements in shoulder reconstructive surgery over the past 30 years. It is able to successfully decrease pain and improve function for patients with rotator cuff-deficient shoulders. The glenoid is transformed into a sphere that articulates with a humeral socket. The current reverse prosthesis shifts the center of rotation more medial and distal, improving the deltoid's mechanical advantage. This design has resulted in successful improvement in both active shoulder elevation and in quality of life.

Reconstruction of massive uncontained glenoid defects using a combined autograft-allograft construct with reverse shoulder arthroplasty: preliminary results

BACKGROUND

This report documents our experiences with a new technique for reconstructing massive uncontained defects of the glenoid with reverse total shoulder arthroplasty.

MATERIALS AND METHODS

We use a modified deltopectoral approach to perform the combined allograft-autograft construct glenoid reconstruction. We make use of a peripherally seated cortical allograft acting as a sleeve bushing to provide a stable ring under compression in which to house impacted cancellous autograft centrally for early incorporation and in-growth with the long-peg Aequalis (Tornier, Saint-Ismier Cedex, France) reverse total shoulder arthroplasty baseplate.

RESULTS

Our case series now comprises 10 patients with postoperative follow-up of up to 36 months. We report the first 5 patients here, all of whom have more than 12 months of follow-up. Computed tomography scanning demonstrates incorporation of the graft as early as 6 months. None of these patients have had loosening, implant failures, dislocations, periprosthetic fractures, or infections. One patient sustained an acromial stress fracture that was successfully treated nonoperatively, and 1 patient has nonprogressive grade I notching.

CONCLUSION

The hybrid graft glenoid reconstruction is a useful and versatile technique in the setting of massive uncontained defects of the glenoid and permits the implantation of a reverse total shoulder arthroplasty. We believe this technique is reproducible and uses materials that are both readily available and familiar.

Rotator cuff tear arthropathy: evaluation, diagnosis, and treatment: AAOS exhibit selection

Rotator cuff tear arthropathy encompasses a broad spectrum of pathology, but it involves at least three critical features: rotator cuff insufficiency, degenerative changes of the glenohumeral joint, and superior migration of the humeral head. Although many patients possess altered biomechanics of the glenohumeral joint secondary to rotator cuff pathology, not all patients develop rotator cuff tear arthropathy, and thus the exact etiology of rotator cuff tear arthropathy remains unclear. The objectives of this manuscript are to (1) review the biomechanical properties of the rotator cuff and the glenohumeral joint, (2) discuss the proposed causes of rotator cuff tear arthropathy, (3) provide a brief review of the historically used surgical options to treat rotator cuff tear arthropathy, and (4) present a treatment algorithm for rotator cuff tear arthropathy based on a patient's clinical presentation, functional goals, and anatomic integrity.

Muscle degeneration in rotator cuff tears

Rotator cuff tears are among the most common injuries seen by orthopedic surgeons. Although small- and medium-sized tears do well after arthroscopic and open repair, large and massive tears have been shown to develop marked muscle atrophy and fatty infiltration within the rotator cuff muscles. These pathologic changes have been found to be independent predictors of failed surgical repair with poor functional outcomes. To understand the pathophysiology of rotator cuff disease, we must first develop an understanding of the changes that occur within the cuff muscles themselves. The purpose of this review is to summarize the molecular pathways behind muscular degeneration and emphasize new findings related to the clinical relevance of muscle atrophy and fatty infiltration seen with rotator cuff tears. Understanding these molecular pathways will help guide further research and treatment options that can aim to alter expression of these pathways and improve outcomes after surgical repair of massive rotator cuff tears.

Rotator cuff deficient arthritis of the glenohumeral joint

Rotator cuff deficient arthritis of the glenohumeral joint, especially cuff tear arthropathy, has proved a challenging clinical entity for orthopaedic surgeons ever since Charles Neer originally detailed the problem in 1983. Understanding has improved regarding the pathophysiology and pathomechanics underlying cuff tear arthropathy. Surgical reconstruction options can lead to excellent outcomes for patients afflicted with these painful and functionally limited shoulders. Humeral hemiarthroplasty and reverse total shoulder arthroplasty have jumped to the forefront in the treatment of cuff tear arthropathy. As studies continue to look at the results of these procedures in cuff tear arthropathy, existing indications and treatment algorithms will be further refined. In this article the history and pathophysiology of cuff tear arthropathy are reviewed. Additionally, the clinical findings and results of surgical reconstruction are discussed.

Observations on retrieved humeral polyethylene components from reverse total shoulder arthroplasty

HYPOTHESIS

Analyses of polyethylene components retrieved at revision of total knee, hip, and shoulder replacements have been used to study the effect of design, patient, and surgical factors on initial implant performance, but no studies have reported similar types of findings in retrieved humeral polyethylene components in reverse total shoulder arthroplasty. Our hypothesis is that while the conforming surface of the humeral polyethylene may predispose it to surface wear modalities, as seen in total hip arthroplasty, the presence of clinical instability may also increase the occurrence of focal contact stresses leading to subsurface fatigue failure.

MATERIALS AND METHODS

Fourteen humeral polyethylene components were retrieved from revision surgery at a single institution. Each polyethylene was analyzed for 9 modes of damage in each of 4 quadrants into which the bearing surface was divided. For each implant, the most recent radiographs before removal were scored using an adapted radiolucency score, and glenosphere positioning was measured.

RESULTS

Despite the short mean length of implantation (0.46 ± 0.5 years), scratching and abrasion were seen in 14 and 13 components, respectively, followed by third-body debris and pitting. The modes of damage observed were most severe in the inferior quadrant of the humeral polyethylene. Scapular notching, glenoid, and humeral radiolucencies were prevalent on preoperative radiographs, but their long-term significance has not yet been elucidated. Increased glenosphere inclination was associated with decreased superior and total glenoid radiolucency, along with total polyethylene wear scores.

DISCUSSION

Promising early, functional results with the use of reverse total shoulder arthroplasty has led to the increased expansion of its use, but high complication and revision rates continue to raise concerns regarding implant longevity. The presence of a clinical, adduction deficit may predispose patients to inferior quadrant polyethylene wear.

CONCLUSIONS

Impingement of the humeral polyethylene at the lateral edge of the scapula leads to inferior quadrant wear and associated polyethylene failure, and implant instability may predispose the components to fatigue wear mechanisms. Analysis of retrieved humeral polyethylene components, along with patient, design, and surgical factors, provide important information on the causes of component failure.

Short-term results after reversed shoulder arthroplasty (Delta III) in patients with rheumatoid arthritis and irreparable rotator cuff tear

The purpose of this study was to describe the outcome after reversed Delta III shoulder prosthesis in patients with rheumatoid arthritis (RA) and irreparable rotator cuff tear. Fifteen patients (17 joints) were prospectively analysed using the Constant-Murley score (CS). Comprehensive outcome measure was carried out by means of four widely used questionnaires as well as clinical and radiographic examinations at an average of 24.3 months postoperatively. The CS improved significantly from 19 to 59.5 points. The mental (MSC) and physical (PCS) component summary score of the Short Form 36 (SF-36) reached 108% and 77%, respectively, while the DASH (Disabilities of the Arm, Shoulder, and Hand) was 58% of a comparative norm population. Remaining deficits were documented by SPADI (Shoulder Pain and Disability; 54.4 points) and ASES (clinical and patient-orientated American Shoulder and Elbow Surgeons; 84.3 and 61.3 points, respectively). No radiological signs of loosening were found, but scapular notching occurred in four cases. Reversed arthroplasty provides a substantial improvement of shoulder function in patients with RA. The high incidence of notching is of concern.

Cuff tear arthropathy: current trends in diagnosis and surgical management

Massive tears of the rotator cuff resulting in arthritis of the glenohumeral joint remain a difficult challenge. Although cuff tear arthropathy (CTA) has been recognized for more than 150 years, a treatment strategy with uniformly satisfactory outcomes remains elusive, partly due to the difficulty in defining CTA in the literature. Most studies combine true CTA, rheumatoid arthritis, and massive rotator cuff tears under the CTA diagnosis. Determining outcomes from these studies is difficult. Hemiarthroplasty and total shoulder arthroplasty have led to pain relief, but the high rate of glenoid component loosening after total shoulder arthroplasty is a concern, and active range of motion remains limited after hemiarthroplasty. There is increasing interest in the use of a constrained or reverese total shoulder arthroplasty to treat this complex process, with promising early results. This review article studies current trends in the diagnosis and management of arthritis due to massive cuff tears and CTA.

Latissimus dorsi transfer to restore external rotation with reverse shoulder arthroplasty: a biomechanical study

In patients with pseudoparesis of the shoulder resulting from irreparable rotator cuff tears, reverse shoulder arthroplasty (RSA) can restore active elevation, but external rotation remains less predictable. Latissimus dorsi transfer (LDT) has been shown to be effective in restoring external rotation in patients with posterosuperior tears of the rotator cuff. The aim of this study is to determine the capacity of the LDT to restore external rotation in combination with RSA and to investigate the mechanical advantage produced by 3 different insertion sites. A biomechanical model was created using a reverse total shoulder prosthesis with 3 different transfer insertions. Moment arms were measured for 2 static positions and 1 motion of the humerus. The moment arm analysis showed that LDT can improve active external rotation in the setting of a reverse prosthesis. An insertion site on the posterior side of the greater tuberosity (adjacent to the teres minor insertion) produced a greater external rotation moment arm.

Pulsed radiofrequency applied to the suprascapular nerve in painful cuff tear arthropathy

The purpose of this study was to assess the efficacy of pulsed radiofrequency (PRF) applied to the suprascapular nerve for pain relief in medically unfit patients with painful cuff tear arthropathy. Twelve patients with chronic shoulder pain due to cuff tear arthropathy were recruited. The mean age was 68 years (range, 60-83 years). The suprascapular nerve was targeted at the suprascapular notch with PRF. The patients were assessed with the Oxford score, Constant score, and visual analog scale (VAS) pain score before ablation and 3 and 6 months after ablation. Statistical analysis was undertaken by use of the Friedman test. Ten patients showed improvement in the VAS score (P = .24) and Constant score (P = .005) and eleven in the Oxford score (P = .001). There was a deterioration in the VAS scores between 3 and 6 months, suggesting that the benefits were starting to wear off with time (P > .05). We conclude that PRF may be a useful therapeutic adjunct in patients with painful, end-stage rotator cuff tear arthropathy who are medically unfit for surgery.

Hemiarthroplasty for the rotator cuff-deficient shoulder

BACKGROUND

Hemiarthroplasty is a common treatment for cuff tear arthropathy and glenohumeral arthritis associated with a massive tear of the rotator cuff; however, to our knowledge, long-term outcomes and preoperative factors affecting results have not been reported.

METHODS

Thirty-four shoulders in thirty-one patients with cuff tear arthropathy or a massive rotator cuff tear with glenohumeral arthritis underwent hemiarthroplasty at an average age of seventy-two years. Outcomes in all patients were evaluated by direct physical examination and according to the limited goals criteria of Neer et al. at a mean of 3.7 years postoperatively. In twenty-five shoulders, long-term outcomes were measured with use of the American Shoulder and Elbow Surgeons (ASES) scoring system and follow-up data were obtained at a mean of ten years (range, four to sixteen years) postoperatively.

RESULTS

Twenty-six of thirty-four shoulders satisfied the limited goals criteria described by Neer et al. The mean active forward elevation improved from 78 degrees preoperatively to 111 degrees postoperatively (p < 0.001). The mean active external rotation improved from 15 degrees preoperatively to 38 degrees postoperatively (p < 0.0001). One patient with a history of four failed rotator cuff repairs had anterosuperior instability develop after surgery. The mean final total ASES score was 67 points (range, 35 to 100 points). Of the sixteen shoulders in patients who could actively elevate the arm to >or=90 degrees preoperatively, fourteen achieved satisfactory results according to the limited goals criteria of Neer et al. Patients who could actively elevate the arm to 90 degrees had significantly better function (mean ASES function score, 31 compared with 23 points; p = 0.05), pain relief (mean ASES pain score, 48 compared with 30 points; p = 0.002), and higher total ASES scores (mean, 80 compared with 54 points; p < 0.001) than the patients who were unable to actively elevate the arm to 90 degrees .

CONCLUSIONS

Hemiarthroplasty can provide good long-term results in rotator cuff-deficient patients with glenohumeral arthritis. Patients who have preoperative forward elevation of >or=90 degrees benefit the most. A low complication rate can be expected for this procedure.

Biomechanical comparison of component position and hardware failure in the reverse shoulder prosthesis

There has been renewed interest in reverse shoulder arthroplasty for the treatment of glenohumeral arthritis with concomitant rotator cuff deficiency. Failure of the prosthesis at the glenoid attachment site remains a concern. The purpose of this study was to examine glenoid component stability with regard to the angle of implantation. This investigation entailed a biomechanical analysis to evaluate forces and micromotion in glenoid components attached to 12 polyurethane blocks at -15 degrees, 0 degrees, and +15 degrees of superior and inferior tilt. The 15 degrees inferior tilt had the most uniform compressive forces and the least amount of tensile forces and micromotion when compared with the 0 degrees and 15 degrees superiorly tilted baseplate. Our results suggest that implantation with an inferior tilt will reduce the incidence of mechanical failure of the glenoid component in a reverse shoulder prosthesis.

Rehabilitation following total shoulder arthroplasty

Total shoulder arthroplasty (TSA) is a standard operative treatment for a variety of disorders of the glenohumeral joint. Patients, who have continued shoulder pain and loss of function in the presence of advanced joint pathology, despite conservative management, are often managed by undergoing a TSA. The overall outcomes that are reported after surgical intervention are quite good and appear to be primarily determined by the underlying pathology and the tissue quality of the rotator cuff. The current Neer protocol for postoperative TSA rehabilitation is widely used and based on tradition and the basic science of soft tissue and bone healing. The purpose of this paper is to review the indications for TSA, focusing on the underlying pathologies, and to describe the variables that impact the rehabilitation program of individuals who have had a TSA. A postoperative TSA rehabilitation protocol and algorithm, founded on basic science principles and tailored toward the specific clinical condition, are presented.

Management of irreparable rotator cuff tears and glenohumeral arthritis

Glenohumeral arthritis with irreparable rotator cuff tears remain a difficult entity to treat. Varied causes include rotator cuff tear arthropathy, osteoarthritis, or rheumatoid arthritis with irreparable cuff tear. Common symptoms are progressive pain and dysfunction. Physical examination may reveal pain, crepitance, rotator cuff weakness, and loss of motion and function. Radiographs may reveal varying degrees of osteophyte formation, sclerotic bone, superior humeral head migration, and bony erosion. Additional imaging modalities may reveal cuff tear size, retraction, atrophy, and fatty infiltration. Failure of nonoperative management may lead to operative intervention. Rotator cuff repair or reconstruction may help prevent progression of tears and future arthritic changes. In patients with moderate to severe glenohumeral arthritis and irreparable rotator cuff tears, hemiarthroplasty is currently the procedure of choice. For patients with severe cuff dysfunction or loss of coracoacromial arch, or for patients who require revision, the reverse shoulder prosthesis may offer a treatment option. Future management continues to be defined with additional study.

Shoulder prostheses treating cuff tear arthropathy: a comparative biomechanical study

Painful cuff tear arthropathy (CTA) affects the independence of the elderly. Surgical treatment often consists of joint replacement, the functional outcome of which remains variable. Knowledge of the biomechanical properties of the different prosthetic designs can guide the orthopaedic surgeon in the choice of implant to predict its clinical result. A 3-D computer model of the glenohumeral joint is used to analyse the moment of the deltoid muscle in the scapular plane. A geometrical 3-D ball-and-socket model of the shoulder joint was used to calculate (1) the angle-force relationships, (2) the moment arm of the deltoid muscle and (3) the moment of the deltoid muscle components, for increasing degrees of arm elevation in the scapular plane. In this 3-D model, a clinical thoraco-scapular rhythm analysis was implemented, based on measurements in normal subjects, patients treated with an anatomical prosthesis and patients treated with an inversed delta III prosthesis. These data were compared for 10 different prosthetic treatment options.

RESULTS

Muscle angle-force curves show a favourable slope in non-anatomical prosthetic designs, where the centre of rotation of the glenohumeral joint is medialized, the deltoid muscle is elongated and the humeral shaft is lateralized. On the contrary, anatomical prosthetic designs do not perform well in this computer analysis.

CONCLUSIONS

From a biomechanical point of view, a shoulder prosthesis which medializes the centre of rotation, lengthens the deltoid muscle and increases the deltoid lever arm, results in a significantly more powerful abduction of the shoulder, despite complete loss of rotator cuff function.

RELEVANCE

This study explains why a successful functional outcome can be expected in CTA with a reversed prosthesis.

Preoperative factors associated with improvements in shoulder function after humeral hemiarthroplasty

BACKGROUND

The relationship between the characteristics of the shoulder that can be determined before humeral hemiarthroplasty and the functional improvement after surgery is not known. The goal of this study was to test the hypothesis that the functional outcome of this procedure correlated significantly with factors that are identifiable preoperatively.

METHODS

The study group included seventy-one shoulders in sixty-eight patients undergoing hemiarthroplasty, performed by the same surgeon, for diagnoses other than acute fracture. The mean age of the patients was sixty-one years (range, thirty to eighty-three years). The results were characterized in terms of the change in self-assessed shoulder function and general health status at an average of forty-nine months (range, twenty-four to 142 months) after surgery.

RESULTS

The preoperative absence of erosion of the glenoid was associated with greater improvement in shoulder function and level of comfort after hemiarthroplasty (p < 0.001). Shoulders that had not had previous surgery had greater functional improvement than did those that had previous surgery (p = 0.012). Shoulders with an intact rotator cuff showed significantly (p < 0.5) greater improvement in the ability to lift weight above shoulder level after hemiarthroplasty (p <0.5). With regard to diagnoses, shoulders with rheumatoid arthritis, capsulorrhaphy arthropathy, and cuff tear arthropathy had the least functional improvement, whereas those with osteonecrosis (p = 0.0004) and with primary (p = 0.02) and secondary degenerative joint disease (p = 0.03) had the greatest improvement. Patient age and gender did not significantly affect the outcome.

CONCLUSIONS

These results suggest that the functional improvement following humeral hemiarthroplasty is related to factors that are identifiable before surgery. These data may be of benefit in preoperative discussions with patients who have a shoulder disorder and are considering treatment with hemiarthroplasty.

Radiographic evaluation of osteoarthritis

Osteoarthritis is the most widespread form of arthritis in the United States. Classically, osteoarthritis has been grouped into primary and secondary types. Primary or idiopathic osteoarthritis is believed to be a sequela of altered biomechanical stresses across joints in susceptible individuals. Secondary osteoarthritis is a consequence of underlying cartilage damage, such as from preceding inflammatory arthritis, metabolic abnormality, or injury. The radiographic hallmark of osteoarthritis is asymmetric loss of cartilage space. Osteophytosis bony eburnation, subchondral cysts, and eventual subluxation follow. Osteoporosis and erosions are not usual features of this disease.

Surface pretreatments for medical application of adhesion

Medical implants and prostheses (artificial hips, tendono- and ligament plasties) usually are multi-component systems that may be machined from one of three material classes: metals, plastics and ceramics. Typically, the body-sided bonding element is bone. The purpose of this contribution is to describe developments carried out to optimize the techniques, connecting prosthesis to bone, to be joined by an adhesive bone cement at their interface. Although bonding of organic polymers to inorganic or organic surfaces and to bone has a long history, there remains a serious obstacle in realizing long-term high-bonding strengths in the in vivo body environment of ever present high humidity. Therefore, different pretreatments, individually adapted to the actual combination of materials, are needed to assure long term adhesive strength and stability against hydrolysis. This pretreatment for metal alloys may be silica layering; for PE-plastics, a specific plasma activation; and for bone, amphiphilic layering systems such that the hydrophilic properties of bone become better adapted to the hydrophobic properties of the bone cement. Amphiphilic layering systems are related to those developed in dentistry for dentine bonding. Specific pretreatment can significantly increase bond strengths, particularly after long term immersion in water under conditions similar to those in the human body. The bond strength between bone and plastic for example can be increased by a factor approaching 50 (pealing work increasing from 30 N/m to 1500 N/m). This review article summarizes the multi-disciplined subject of adhesion and adhesives, considering the technology involved in the formation and mechanical performance of adhesives joints inside the human body.

Bipolar hemiarthroplasty for chronic rotator cuff tear arthropathy

Massive rotator cuff tears associated with glenohumeral arthritis are currently an unsolvable clinical entity. We review our series of 14 patients with rotator cuff tear arthropathy (RCTA) who underwent a bipolar prosthesis of the shoulder. The average follow up was 27.8 months (range, 24-48 months), and the average age was 71 years (range, 57-84 years). Of these 14 patients, 9 were men and 5 women. None of these patients had undergone previous shoulder surgery, and all patients underwent conservative treatment that failed to improve their symptoms or range of motion. Preoperatively, the average active forward flexion was 30 degrees, active external rotation was 10 degrees, and the American Shoulder and Elbow Society (ASES) score was 25 points. Postoperatively, the average active forward flexion improved to 88 degrees, active external rotation increased to 37 degrees, and the ASES score improved to 80 points. Of the 14 patients, 12 stated that they had no pain with activities of daily living. Two patients continued to have moderate pain in everyday activity.

Bone destruction, upward migration, and medialisation of rheumatoid shoulder: a 15 year follow up study

OBJECTIVE

To evaluate bone destruction, upward migration, and medialisation of the glenohumeral (GH) joint in a cohort of 74 patients with seropositive and erosive rheumatoid arthritis followed up prospectively.

METHODS

At the 15 year follow up 148 shoulders were radiographed by a standard method. Bone destruction in the GH joint was examined from the radiographs by four methods, of which three measured the migration and one the remodelling of the humeral head. The distances from the greater tuberosity of the humeral head to the coracoid process (medialisation distance (MD)) and to the articular surface of the humeral head (GA) have been previously developed to evaluate the preoperative offsets of the arthritic GH joint. Medial displacement index (MI) and upward migration index (UI) have been recently developed to evaluate the destructive pattern of the rheumatoid GH joint. Destruction of the GH joints was assessed by the Larsen method on a scale of 0 to 5. The relation between the measurements and the grade of destruction of the GH joints was examined. UI was compared with our previous measurements of the subacromial space.

RESULTS

Both the MI and the UI had a negative correlation with the GH joint destruction (Larsen grade), r=-0.49 (95% CI -0.36 to -0.60) and r=-0.58 (95% CI -0.46 to -0.68). The UI correlated significantly with the subacromial space, r=0.90 (95% CI 0.86 to 0.93). The mean MI and UI measurements of the non-affected joints were within the reported normal variation. The mean MD collapsed between Larsen grades 4 (83.0 mm) and 5 (65.5 mm). The morphology of the humeral head began to flatten and erode from the grade 3 onwards and medial head destruction was detected at grade 5.

CONCLUSIONS

Medialisation seems to be preceded by upward migration of the humeral head, indicating rotator cuff damage. Symptomatic Larsen grade 3 shoulders should be intensively followed up by clinical and radiological means. If a total shoulder arthroplasty is considered, an orthopaedic consultation is worthwhile at a sufficiently early stage (Larsen 3 and 4), when soft tissue structures responsible for function are still in proper condition and timing of the operative procedure can be well planned.