Design of an electrospun tubular construct combining a mechanical and biological approach to improve tendon repair.

Hand tendon injuries represent a major clinical problem and might dramatically diminish a patient's life quality. In this study, a targeted solution for flexor tendon repair was developed by combining a mechanical and biological approach. To this end, a novel acrylate-endcapped urethane-based polymer (AUP) was synthesized and its physico-chemical properties were characterized. Next, tubular repair constructs were developed using electrospinning of the AUP material with incorporated naproxen and hyaluronic acid (i.e. anti-inflammatory and anti-adhesion compounds, respectively), and with a tubular braid as mechanical reinforcement. Tensile testing of the repair constructs using ex vivo sheep tendons showed that the developed repair constructs fulfilled the required mechanical properties for tendon repair (i.e. minimal ultimate stress of 4 MPa), with an ultimate stress of 6.4 ± 0.6 MPa. Moreover, in vitro biological assays showed that the developed repair tubes and the incorporated bioactive components were non-cytotoxic. In addition, when equine tenocytes and mesenchymal stem cells were co-cultured with the repair tubes, an increased production of collagen and non-collagenous proteins was observed. In conclusion, this novel construct in which a mechanical approach (fulfilling the required mechanical properties) was combined with a biological approach (incorporation of bioactive compounds), shows potential as flexor tendon repair application. Graphical abstract.

Prevalence and risk factors of scapular stress fracture after reverse shoulder arthroplasty: a multicentric retrospective study.

PURPOSE: Scapular stress fracture (sSF) is a difficult complication to treat after reverse total shoulder arthroplasty (RSA). The aim of this study was to identify the prevalence and possible risk factors in a large population. METHODS: A total of 2165 RSAs that were implanted between January 2006 and October 2017 in five hospitals were evaluated. Within this cohort, sSF was radiologically confirmed. Age, gender, surgical indication and hospital of treatment were determined for the entire cohort. A matched 3:1 case-control study was then performed to investigate several clinical and surgical variables. RESULTS: sSF occurred in 3.1% (63 patients), with a median time interval of five months post-operative [IQR = 9, range: (1-79)]. Within the entire cohort, females (OR = 2.99) and rotator cuff arthropathy (RCA) (OR = 2.79) were more prone to this complication. Age had little influence (OR = 1.03). After exclusion, fifty-five eligible cases were matched to 165 controls based on hospital, gender, age and surgical indication. After univariable analysis, significance was obtained for osteopenia (P = 0.037), osteoporosis (P = 0.032), surgical approach (P = 0.002) and peri-operative acromioclavicular (AC) joint surgery (P = 0.035). Multivariate analysis demonstrated that osteopenia (OR = 3.94), osteoporosis (OR = 2.85) and a deltopectoral approach (OR = 3.70) were independent risk factors. CONCLUSION: According to our findings, older women with poor bone quality and a history of RCA suffered more frequently from sSF. Anterolateral approach during surgery was a surgical protective factor, possibly due to the mobilization of the acromioclavicular joint. Although this study indicates who is at risk for sSF, further investigation for prevention of sSF in these patients is necessary.

Shoulder arthroplasty for glenohumeral osteoarthritis: results from a comprehensive survey in Belgium and the Netherlands.

The purpose of this survey in Belgium and the Netherlands was to assess treatment variation in glenohumeral osteoarthritis between experienced and less experienced orthopedic surgeons, and to investigate perioperative treatment after shoulder arthroplasty in a large group of orthopedic surgeons. Orthopedic surgeons specialized in shoulder surgery were invited to complete a survey between November 2013 and February 2015. Seventy-one percent of the approached surgeons com-pleted the survey. Less experienced surgeons (< 6 years) and surgeons from the Netherlands find patient characteristics (e.g. smoking p=0.01) more relevant than more experienced surgeons (≥ 6 years) and surgeons from Belgium. Less experienced surgeons will less likely (p=0.001) perform resurfacing arthroplasty compare to experienced surgeons. The less and the experienced surgeons use similar indications for a reverse shoulder arthroplasty regarding age limit and cuff arthropathy without osteoarthritis. Less experienced surgeon will more likely (p=0.003) prescribe a low molecular weight heparin during the hospital stay after a shoulder arthroplasty. In this survey, we found a decrease in the use of resurfacing arthroplasty and a strong increase in the use of reverse shoulder arthroplasty. Besides, there is little consensus concerning pre-operative planning, patient characteristics, surgical technique, and patient reported outcome measures. Level of evidence: IV.

Improving the surface properties of an UHMWPE shoulder implant with an atmospheric pressure plasma jet.

Insufficient glenoid fixation is one of the main reasons for failure in total shoulder arthroplasty. This is predominantly caused by the inert nature of the ultra-high molecular weight polyethylene (UHMWPE) used in the glenoid component of the implant, which makes it difficult to adhesively bind to bone cement or bone. Previous studies have shown that this adhesion can be ameliorated by changing the surface chemistry using plasma technology. An atmospheric pressure plasma jet is used to treat UHMWPE substrates and to modify their surface chemistry. The modifications are investigated using several surface analysis techniques. The adhesion with bone cement is assessed using pull-out tests while osteoblast adhesion and proliferation is also tested making use of several cell viability assays. Additionally, the treated samples are put in simulated body fluid and the resulting calcium phosphate (CaP) deposition is evaluated as a measure of the in vitro bioactivity of the samples. The results show that the plasma modifications result in incorporation of oxygen in the surface, which leads to a significant improved adhesion to bone cement, an enhanced osteoblast proliferation and a more pronounced CaP deposition. The plasma-treated surfaces are therefore promising to act as a shoulder implant.

The morphometric anatomy of the delto-fulcral triangle: A 3D CT-based reconstruction study.

This study introduced the new delto-fulcral triangle (DFT), the first anatomical model of its kind. As seen from the orthopaedician's supraspinatus-outlet view, the antero-superior point of the coracoid process along with the lateral- and posterior-most acromial landmarks form the boundaries of the DFT. Since these osseous scapular landmarks accounted for both dynamic and static stabilisers of the glenohumeral joint, knowledge of the anatomical features of the DFT may prove beneficial to the orthopaedic surgeon. This study thus aimed to investigate the morphometry of the new DFT. The bony surfaces of one-hundred and sixty-nine (n = 169) normal and pathological (Omarthrosis and Cuff-Tear Arthropathy) shoulders from the hospital's CT scan database were reconstructed (Mimics®: Materialise, Leuven, Belgium). Statistical significance was observed between all three groups for Side 2 (LACPF: distance between most lateral and most posterior points of the acromion) and angles α (angle between sides 1 and 3) and ß (angle between sides 1 and 2) of the DFT. It was postulated that although pathological cases present with a smaller lateral acromial distance (LACPF), their lateral acromion landmark is more posteriorly placed from the scapular plane than that of a normal case. As the aspects of the morphometric anatomy of the DFT presented with levels of statistical significance, it may provide a means to evaluate the anatomy of normal and pathological cases. Additionally, the three osseous scapular landmarks that create the DFT are clearly visualised and palpable, therefore they are easily reproducible from both X-ray images and CT scans.

Arthroscopic treatment of the young degenerative shoulder joint ; is there a role for interpositioning arthroplasty ?

We evaluate our experience with arthroscopic interpositioning arthroplasty as a treatment of the young degenerative shoulder joint. Between 2007 and 2009 ten patients were treated with either a dermal allograft or a meniscal allograft. In seven patients the graft failed and within 13 months these were revised to a total shoulder arthroplasty. Three patients are still satisfied after 7 to 8 years follow-up. Biologic resurfacing of the glenoid may have a role in the management of glenohumeral arthritis in the young and active patient, but the optimal graft and pathology still need to be defined.

Heterotopic ossification after reverse total shoulder arthroplasty.

AIMS: Heterotopic ossification (HO) occurs after arthroplasty, especially total hip arthroplasty. In this study we describe the incidence, evolution, morphology and clinical consequences of HO following reverse shoulder arthroplasty. PATIENTS AND METHODS: This is a single-centre retrospective study of 132 consecutive patients who received a Delta III or Delta Xtend reverse total shoulder arthroplasty between 2006 and 2013 for the treatment of cuff tear arthropathy. There were 96 women and 36 men. Their mean age at the time of surgery was 69 years (49 to 89) and the mean follow-up was 36 months (12 to 84). The incidence, evolution, morphology and clinical consequences of HO using the Constant-Murley score (CS) were analysed. A modified Brooker classification of HO of the hip was used. RESULTS: HO was seen in 39 patients (29.5%). A total of 31 of these patients (81.6%) began to develop HO by three months post-operatively. According to the Hamada classification, 11 patients had grade 1a, eight had grade 1b, six had grade 1c and 14 had grade 2 HO. The HO evolved over a mean of 8.3 months (3 to 21). Patients with HO had a lower mean CS at three (p = 0.017), six (p < 0.001) and 12 months (p < 0.001) post-operatively. HO was not associated with notching (p = 0.675). CONCLUSION: HO after reverse shoulder arthroplasty is a non-progressive condition without long-term clinical consequences. Only grade 2 HO is clinically relevant with a negative effect on the function of the shoulder during its development. Cite this article: Bone Joint J 2016;98-B:1215-21.

Parameters influencing glenoid loosening.

INTRODUCTION: There is a lack of organization in existing studies on the outcome and complications of total shoulder arthroplasty. As a result, it is difficult to gain substantial evidence regarding the rate and risk factors for the occurrence of glenoid loosening which remains the most common cause of prosthetic failure. To improve the quality of future studies, an agreement should exist on definitions of glenoid loosening and on the potential risk factors. AREAS COVERED: Reviewing the literature, loosening can be defined as the appearance of radiolucent lines, radiological loosening, clinical loosening and revision as the end stage. Three different categories of influencing parameters can be distinguished: implant related, patient related and surgeon related. Expert commentary: The aim of this review is to organize the available knowledge on glenoid failure, as well as to describe the gaps so that it will constructively contribute to the debate on how to prevent glenoid failure in the anatomic total shoulder arthroplasty.

Reversed shoulder arthroplasty as treatment for late or ancient chronic glenohumeral dislocation.

Chronic glenohumeral dislocation is a rare entity and several treatment options have been proposed. The aim of this study is to report the long-term follow-up of the reversed shoulder arthroplasty in patients with chronic glenohumeral dislocation. A retrospective analysis of all patients between January 2002 and December 2012 that were treated with a reversed shoulder arthroplasty for chronic anterior glenohumeral dislocations was performed. Pre-operative CT evaluation of the bone loss and fatty degeneration of the rotator cuff muscles was performed. Pre- and postoperative Constant-Murley score was evaluated. 6 patients (4 males and 2 females) with anterior glenohumeral dislocations were evaluated. Average age was 73 years (between 65-86 years). The average time of dislocation was 18 weeks (between 4 and 52 weeks). Average time of follow-up was 39 months (between 12 and 90 months). The CM improved from 33 (between 17 and 45) pre-op to 76 postop (between 55 and 89). No postoperative complications were observed. Reversed shoulder arthroplasty gives good results in case of chronic glenohumeral dislocation.

Evaluation of prominence of straight plates and precontoured clavicle plates using automated plate-to-bone alignment.

Hardware prominence after plate fixation for clavicle fracture is a common complication. The aim of the study was to perform a 3D analysis of the prominence of different types of superior clavicle plates. An automated fitting of 3 straight and 10 precontoured plates was performed on 52 3D-CT-scan reconstructed cadaver clavicles. The mean and maximum bone-plate distance and maximum prominence was significant higher with the straight plates compared to the precontoured plates. The mean and maximum boneplate distance was significant higher with the precontoured DePuy-Synthes plates compared to the precontoured Acumed plates but when evaluating the maximum prominence there was no significant difference between the most commonly used 8-holes plates. To conclude, precontoured plates of the clavicula diminish significantly hardware prominence. There exists a difference in hardware prominence between different brands of precontoured plates but this difference is limited and in most cases not significant.

Reversed Revised: What to do when it goes wrong?

UNLABELLED: Reversed total shoulder arthroplasty (RTSA) has well known indications and good to excellent results are described in the literature. When the arthroplasty fails however, revision remains a technical challenge with many questions unanswered. To analyse retrospectively and consecutively the indications and results of primary RTSA-revision. All patients that underwent revision RTSA between 2004 and 2009 were included. Indications for surgery, surgical details and clinical evaluation with the preand postoperative Constant-score (CS) were analyzed. 37 Revisions (37 patients) of RTSA were analysed with an average follow up of 41.2 months (24-84). Indications were infection (23), glenoid loosening (9), instability (2) malpositioning (2) and suprascapular nerve irritation (1). 25 patients obtained a one-stage conversion to a new reversed prosthesis; 4 patients obtained a two-stage revision; 8 patients got a megahead prosthesis. No difference in reinfection rate is seen between one- and two stage techniques. An overall lower CS is seen for the mega-head prosthesis. CONCLUSIONS: The main indication for revision was infection. Revision of RTSA to a new reversed prosthesis is to prefer even when several procedures are necessary in one patient. When this is impossible, a mega-head prosthesis is to consider and gives reasonable results.

One-stage revision for patients with a chronically infected reverse total shoulder replacement.

We retrospectively reviewed 11 consecutive patients with an infected reverse shoulder prosthesis. Patients were assessed clinically and radiologically, and standard laboratory tests were carried out. Peroperative samples showed Propionbacterium acnes in seven, coagulase-negative Staphylococcus in five, methicillin-resistant staphylococcus aureus in one and Escherichia coli in one. Two multibacterial and nine monobacterial infections were seen. Post-operatively, patients were treated with intravenous cefazolin for at least three days and in all antibiotic therapy was given for at least three months. Severe pain (3 of 11) or severe limitation of function (3 of 11) are not necessarily seen. A fistula was present in eight, but function was not affected. All but one patient were considered free of infection after one-stage revision at a median follow-up of 24 months, and without antibiotic treatment for a minimum of six months. One patient had a persistent infection despite a second staged revision, but is now free of infection with a spacer. Complications included posterior dislocation in one, haematoma in one and a clavicular fracture in one. At the most recent follow-up the median post-operative Constant-Murley score was 55, 6% adjusted for age, gender and dominance. A one-stage revision arthroplasty reduces the cost and duration of treatment. It is reliable in eradicating infection and good functional outcomes can be achieved.

Shoulder prostheses treating cuff tear arthropathy: a comparative biomechanical study.

UNLABELLED: 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.

About the variability of the shape of the glenoid cavity.

The morphology of the glenoid cavity is highly variable, and no consensus exists regarding how to classify the different forms. We examined 98 dry scapulae to identify a common morphological entity and to define reproducible bony references of the glenoid cavity. The glenoid cavities were photographed perpendicularly in a standardized fashion. The bony peripheral rim was studied on these two-dimensional images, defined by randomly chosen points in order to define one or more circles. This study showed that only the peripheral rim of the inferior quadrants of the articular surface was found to be located on a circle ( P=0.926) with a radius of 12.8 mm (SD 1.3 mm). Defining the center of this circle appeared to be more reliable (ICC 0.98) than determining the middle point of the longitudinal axis (0,0) between the most cranial and most caudal points, defined as Saller's line (ICC 0.89). The distance of the center of this projected circle to the middle point of Saller's line had a unimodal distribution, suggesting the existence of only one glenoid cavity morphotype. We then investigated the relationship between the center of the circle and the area of subchondral bone thickening under the bare spot, the so-called tubercle of Assaki. Ten phenolized cadaveric glenoid cavities were examined with computed tomography. A circle was projected on the first image showing the bony peripheral rim, and this circle was copied on the consecutive slices until the tubercle of Assaki came across. The center of the circle was located within the area of the tubercle of Assaki, in all but one specimen. To investigate the clinical implications of this finding, the cadaver specimens were used to compare the position of the center of the circle with the postulated center of implantation according to the literature, and to the reference guide for a commonly used total shoulder prosthesis. The center of the circle was consistently situated more distal than the postulated center of the guide (mean 5.5 mm, range 4-8 mm) and the middle point of the glenoid cavity (mean 2 mm, range 1-3 mm). These findings could offer a reproducible point of reference for the glenoid cavity in osseous anthropometry and a valuable reference in shoulder replacement surgery, and might help in the definition of osseous glenohumeral instability.

Consequences of deltoid muscle elongation on deltoid muscle performance: a computerised study.

BACKGROUND: The deltoid muscle plays an important role in normal shoulder function. Knowledge of the position of the glenohumeral rotational centre and of the deltoid muscle length is essential to understand optimal placement of a total shoulder prosthesis. OBJECTIVE: This study is designed to analyse the effect of deltoid muscle elongation on shoulder joint function. DESIGN: A three-dimensional model of the glenohumeral joint with deltoid muscle analysis in the scapular plane. METHODS: A geometrical three-dimensional ball-and-socket model of the shoulder joint was developed. From dry bones, the position of the origins and insertions of the three parts of the deltoid muscle relative to the calculated centre of rotation of the humeral head was defined. The position and the direction of the muscle force working lines relative to this humeral centre were calculated using former measurements and CT-data of the deltoid. Muscle length-tension data were applied to obtain angle-force relationships. The model was used to calculate the angle-force relationships, the moment arm and the moment of the deltoid muscle components for successive arm elevation angles in the scapular plane. These data were compared to those of a theoretical situation assuming a 10% elongation of the muscle. RESULTS: Muscle angle-force curves show a more favourable slope after moderate (10%) deltoid muscle elongation. Elongating the muscle by changing the distance between the humeral rotation point and the deltoid insertion along the humeral axis does not affect moment arms. The moments of the deltoid muscle forces themselves, however, seem more adapted to elevation in the scapular plane. The deltoid maximal moment exceeds the arm-weight moment by about 40% instead of being approximately equal, and that the maximum is situated around 100 degrees of elevation. CONCLUSIONS: From a biomechanical point of view, stretching the deltoid muscle by 10% seems to result in a significantly more favourable position in case of shoulder elevation at 90 degrees of abduction in the scapular plane in a centred glenohumeral joint. RELEVANCE: This model suggests that a 10% elongation of the deltoid muscle, the most important shoulder abductor, improves its ability to elevate the arm. If properly implemented, this observation can be very important in the treatment and early rehabilitation of rotator-cuff-insufficient shoulders treated by a specific total shoulder replacement design.

[Results of an inverted shoulder prosthesis after resection for tumor of the proximal humerus]. / Résultats d'une prothèse d'épaule inversée après résection pour tumeur de l'humérus proximal.

PURPOSE OF THE STUDY: Treatment of primary bone tumors of the proximal humerus is a major challenge, both in terms of oncological cure and limitation of functional handicap. Extracorporal radiation and reimplantation have provided satisfactory results for the treatment of bone tumors and the inverted shoulder prosthesis has be found to be effective in treating rotator cuff deficiency. We therefore assessed patients treated with a combination of these two treatments in order to search for a better functional outcome. MATERIAL AND METHODS: Conservative resection of the tumor with reconstruction using an inverted shoulder prosthesis was performed in six patients with a tumor of the proximal humerus of type Ia or Ib in the Malawer classification or type S3-S4-S5 in the Musculoskeletal Tumor Society classification. Patients whose tumor involved the deltoid or the glenohumeral joint were not considered for this procedure. The series included four men and two women (4 left and 2 right shoulders) aged 51 years on the average at the time of surgery. RESULTS: Mean follow-up was 12 months. The mean age- and sex-adjusted Constant score was 74% (70-85%). The patients were generally satisfied and were able to continue their daily activities. There were two displacements, one of which was diagnosed immediately and reduced without anesthesia. An abduction pad was worn for six months after reduction. The post-operative period was uneventful. No local recurrence has been observed. DISCUSSION: Our results compared favorably with other therapeutic options for resection-reconstruction reported in the literature: functional outcome was better and more predictable, at least in the short term; oncological results were satisfactory although the follow-up is short, particularly for the three primary malignant tumors. It is known however that the long-term oncology result depends on the quality of the resection and the efficacy of the extracorporeal radiation. Shoulder motion outcome was the least satisfactory in patients who experienced peri-operative complications. We were unable to find any relation between less satisfactory functional outcome and the number of surgical procedures for local recurrence before extracorporeal radiation and arthroplasty (deltoid dystrophy). Normal deltoid function appeared to be crucial for optimal functional outcome with this prosthesis which allows sacrifice of the rotators. The rate of complications was low and recovery of active shoulder movement was more rapid. Despite the short-term nature of these results, and despite the risk of loosening, the inverted shoulder prosthesis appears to be an interesting therapeutic option for these patients.

Revision of shoulder replacement with a reversed shoulder prosthesis (Delta III): report of five cases.

The authors report on their experience in revision total shoulder arthroplasty using the Delta III shoulder prosthesis, a reversed constrained prosthesis which is known to give good functional results in the rotator cuff-deficient shoulder. It was implanted in patients with a failed total or hemishoulder prosthesis. The Constant-Murley score was used to assess the functional outcome. The preliminary results achieved in four patients (one bilaterally) are discussed and compared with the results of other treatments. After two years follow-up, the Constant-Murley score has improved from 14/100 preoperatively to 62/100 postoperatively. Although these initially good functional results may be temporary and loosening may occur over the longer term, the authors recommend the Delta III shoulder prosthesis as an alternative solution for revision shoulder arthroplasty.

Examination of the back using the Bunnell scoliometer in a Belgian school population around puberty.

The present study was designed to determine whether quantified clinical measurement of the back would provide arguments supporting a biomechanical cause of adolescent idiopathic scoliosis (AIS). Two hundred ninety-two healthy girls (9 to 16 years) and 191 healthy boys (11 to 18 years) were examined clinically with the use of the Bunnell scoliometer. The inter- and intraobserver measurement error was determined. The accuracy of the Bunnell scoliometer as a biomorphological measurement method is good (variation coefficient +/- 10%). The measurement error is not influenced by the site of the rib hump or the type of scoliosis, but by the magnitude of the deformity to be measured. The present study confirms that the threshold for differentiating a physiological from a pathological gibbosity is 5 degrees C, as advanced by Bunnell (1984). The Bunnell measurement shows no statistically significant differences between boys and girls, although the standard deviation of the measurement in the declive segment is larger in girls. In all spinal segments measured, the scoliometer values show the same evolution in the boys and girls of the various age groups. Although the larger standard deviation in the declive segment in girls favors the existence of a physiological scoliosis, the present study shows no evolution in the various spinal segments for the age groups studied, and therefore does not substantiate the biomechanical etiopathogenic theories for the development of AIS.

Deaths following ingestion of a cardiotoxic plant in Kampuchean children in Thailand.

Twenty-seven Khmer children at a refugee camp in Thailand developed vomiting and diarrhea after ingestion of the seeds of the plant Erythrophleum succirubrum Gagnep. Two children died of cardiac arrest. Ingestion of seed of Erythrophleum species that contain digitalis-like alkaloids causes fatal epidemics of poisoning in children as well as livestock.