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.

Radial head fractures.

The shape and size of the radial head is highly variable but correlates to the contralateral side. The radial head is a secondary stabilizer to valgus stress and provides lateral stability. The modified Mason-Hotchkiss classification is the most commonly used and describes three types, depending on the number of fragments and their displacement. Type 1 fractures are typically treated conservatively. Surgical reduction and fixation are recommended for type 2 fractures, if there is a mechanical block to motion. This can be done arthroscopically or open. Controversy exists for two-part fractures with >2 mm and <5 mm displacement, without a mechanical bloc as good results have been published with conservative treatment. Type 3 fractures are often treated with radial head replacement. Although radial head resection is also an option as long-term results have been shown to be favourable. Radial head arthroplasty is recommended in type 3 fractures with ligamentous injury or proximal ulna fractures. Failure of primary radial head replacement may be due to several factors. Identification of the cause of failure is essential. Failed radial head arthroplasty can be treated by implant removal alone, interposition arthroplasty, revision radial head replacement either as a single stage or two-stage procedure.

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.

Predictors of shoulder degeneration in the Kwazulu-Natal population of South Africa / Indicadores de la degeneración del hombro en la poblacion Kwazulu/Natal de Sudáfrica

SUMMARY: The critical shoulder angle and acromion index are conventional radiological tools employed as predictors of shoulder degeneration. As they represent the static components of glenohumeral stability, the scapulo-humeral geometry and underlying subacromial tissue appear as the resultant cause-effect factors. Consequently, the purpose of this study was to investigate the critical shoulder angle and acromion index as interrelated parameters within the South African population. The measurement of both biomechanical parameters was conducted on two-hundred and sixty (n = 260) true AP radiographs. This was a cross-sectional study that also incorporated the demographic representation of the population group which was analysed accordingly. The mean values recorded for both the critical shoulder angle (36.31±5.84º) and acromion index (0.74±0.13) suggested rotator cuff arthropathy. The results confirmed the theories of Nyffeler et al. (2006) and Moor et al. (2012) who alluded to glenoid inclination and the acromial coverage over the humeral head. A significant proportionality correlation, verified by a P value of 0.000, was established between the acromion index and critical shoulder angle which may assist to differentiate between normal asymptomatic shoulders and those with cuff disease. Furthermore, these predictors of shoulder degeneration may present as a preventative tool against tear progression.

RESUMEN: El ángulo crítico del hombro y el índice acromial son herramientas radiológicas convencionales empleadas como indicadores de la degeneración del hombro. Debido a que representan los componentes estáticos de la estabilidad glenohumeral, la geometría escápulo-humeral y el tejido subacromial subyacente aparecen como los factores causa-efecto resultantes. En consecuencia, el propósito de este estudio fue investigar el ángulo crítico del hombro y el índice acromial como parámetros interrelacionados dentro de la población sudafricana. La medición de ambos parámetros biomecánicos se realizó en 260 radiografías antero-posteriores (AP). Se realizó un estudio transversal que también incorporó la representación demográfica del grupo de la población que fue analizada. Los valores medios registrados tanto para el ángulo crítico del hombro (36,31 ± 5,84º) como para el índice del acromión (0,74 ± 0,13) sugirieron una artropatía del manguito rotador. Los resultados confirmaron las teorías de Nyffeler et al. (2006) y Moor et al. (2012) que aludían a la inclinación glenoide y a la cobertura acromial sobre la cabeza humeral. Se estableció una correlación de proporcionalidad significativa, verificada por un valor de P de 0,000, entre el índice acromial y el ángulo crítico del hombro, lo que puede ayudar a diferenciar entre los hombros asintomáticos normales y aquellos con enfermedad del manguito rotador. Además, estos predictores de degeneración del hombro pueden ser útiles como una herramienta preventiva contra la progresión del desgarro.

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.

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.

The wrist hyperflexion and abduction of the thumb (WHAT) test: a more specific and sensitive test to diagnose de Quervain tenosynovitis than the Eichhoff's Test.

De Quervain's disease has different clinical features. Different tests have been described in the past, the most popular test being the Eichhoff's test, often wrongly named as the Finkelstein's test. Over the years, a misinterpretation has occurred between these two tests, the latter being confused with the first. To compare the Eichhoff's test with a new test, the wrist hyperflexion and abduction of the thumb test, we set up a prospective study over a period of three years for a cohort of 100 patients (88 women, 12 men) presenting spontaneous pain over the radial side of the styloid of the radius (de Quervain tendinopathy). The purpose of the study was to compare the accuracy of the Eichhoff's test and wrist hyperflexion and abduction of the thumb test to diagnose correctly de Quervain's disease by comparing clinical findings using those tests with the results on ultrasound. The wrist hyperflexion and abduction of the thumb test revealed greater sensitivity (0.99) and an improved specificity (0.29) together with a slightly better positive predictive value (0.95) and an improved negative predictive value (0.67). Moreover, the study showed us that the wrist hyperflexion and abduction of the thumb test is very valuable in diagnosing dynamic instability after successful decompression of the first extensor compartment. Our results support that the wrist hyperflexion and abduction of the thumb test is a more precise tool for the diagnosis of de Quervain's disease than the Eichhoff's test and thus could be adopted to guide clinical diagnosis in the early stages of de Quervain's tendinopathy.

A cadaveric study of the structural anatomy of the sternoclavicular joint.

Pathologies of the sternoclavicular (SC) joint are infrequent and effective management is often hindered by a limited understanding of the anatomy. In this study, we did macroscopic evaluations of the ligaments, the intra-articular disc, and the articulating surfaces of 25 SC joints. After removal of the joint capsule, the articulating surfaces of the sternal end of clavicle and the sternum were evaluated and the intra-articular disc was macroscopically examined. The anterior SC ligament covered the intra-articular disc, which divided the joint into a clavicular and a sternal part. A thin capsule, relatively lateral and medial from the anterior SC ligament, covered the two intra-articular parts. This means that the anterior SC ligament can be used as a landmark to enter into clavicular or sternal part of the SC joint. Posteriorly, there was a thick capsule without soft-spot or clear posterior SC ligament. Only the antero-inferior surface of the sternal end of every clavicle was covered by cartilage. Of the intra-articular discs 56% were incomplete. All of these incomplete discs displayed a central hole with signs of degeneration and fraying. This was associated with increased cartilage degeneration at the clavicular side. By experimental design (past and present), it would seem reasonable to assume that the incomplete types are caused by degeneration and are not developmental.