Clinical and radiographic long-term outcomes of hemiarthroplasty for complex proximal humeral fractures

BACKGROUND

Hemiarthroplasty (HA) is a treatment option for complex proximal humeral fractures not suitable for conservative treatment or open reduction-internal fixation. Long-term outcomes using a large-metaphyseal volume prosthesis in the management of proximal humeral fractures have not been reported thus far.

METHODS

Between 2006 and 2010, 41 patients with proximal humeral fractures were treated with HA at our institution (average age, 62 years; age range, 38-85 years). Nine patients underwent revision surgery, 3 were lost to follow-up, and 7 died unrelated to the index surgical procedure. Twenty-two patients were reviewed clinically and radiographically after a mean period of 10.4 years (range, 9-13 years).

RESULTS

Of the 9 HA failures, 7 occurred within the first 2 postoperative years: 2 patients had infections and 5 had greater tuberosity nonunions or malunions. The other 2 patients underwent revision for rotator cuff deficiency >5 years after initial surgery. Among the patients available for final follow-up, the implant survival rate was 71% (22 of 31 patients). At final follow-up, these patients showed a mean relative Constant score of 76% (range, 49%-96%), mean active elevation of 116° (range, 60°-170°), and mean external rotation of 28° (range, 0°-55°). The majority had good or excellent internal rotation, with internal rotation to the 12th thoracic vertebra in 13 patients (59%) and to the eighth thoracic vertebra in 7 (31%). The mean Subjective Shoulder Value was 76% (range, 40%-100%). Clinical outcomes did not significantly deteriorate over a period of 10 years, except for flexion (P < .001) and internal rotation (P = .002). On analysis of greater tuberosity healing, 1 patient had a nonunion and 10 patients (45%) had a malunion, whereas the greater tuberosity had healed in an anatomic position in 12 patients (55%). Patients with a displaced malunion of the greater tuberosity did not have inferior clinical results at last follow-up. Only 2 patients showed glenoid erosion, and in no patients could stem loosening be identified at final follow-up.

CONCLUSION

The revision rate following large-metaphyseal volume HA to treat a proximal humeral fracture was 29% after 10 years postoperatively, with failure within 2 years largely related to greater tuberosity nonunion or malunion and failure later related to rotator cuff insufficiency. Patients with a retained implant showed good clinical and radiographic long-term results, without relevant deterioration over time even when the greater tuberosity healed in a nonanatomic position.

Anterior deltoid muscle reflection using a deltopectoral approach is safe and does not influence outcome of reverse shoulder arthroplasty

BACKGROUND

The deltopectoral approach is well accepted for shoulder arthroplasty procedures. The extended deltopectoral approach with detachment of the anterior deltoid from the clavicle allows increased joint exposure and can protect the anterior deltoid from traction injury. The efficacy of this extended approach has been demonstrated in anatomical total shoulder replacement surgery. However, this has not been shown in reverse shoulder arthroplasty (RSA). The primary aim of this study was to evaluate the safety of the extended deltopectoral approach in RSA. The secondary aim was to evaluate the performance of the deltoid reflection approach in terms of complications, surgical, functional and radiological outcomes up to 24 months post-surgery.

METHODS

A prospective non-randomized comparative study was performed between January 2012 and October 2020 including 77 patients in the deltoid reflection group and 73 patients in the comparative group. Decision for inclusion was based on patient and surgeon factors. Complications were recorded. Patients were followed up for at least 24 months to evaluate their shoulder function and ultrasound evaluation. Functional outcome measures included the Oxford Shoulder Score (OSS), Disabilities of the Arm, Shoulder and Hand (DASH) score, American Shoulder Elbow Surgeons score (ASES), pain intensity (VAS 0-100), range of motion (forward flexion (FF), abduction (AD), and external rotation (ER)). A regression analysis was performed to evaluate any factors of influence on the VAS.

RESULTS

There were no significant differences in the rate of complications between the two groups (14.5% in the deltoid reflection group and 13.8% in the comparative group, p=0.915). Ultrasound evaluation was available in 64 (83.1%) patients, and no proximal detachment was observed. In addition, there were no significant differences in functional outcome measures both preoperatively and at 24 months post-surgery between the groups on Mean VAS pain, OSS, DASH, ASES, FF, ABD, and ER. Adjustment for possible confounders in a regression model indicated that only prior surgery significantly influenced the VAS pain (p=0.031, 95%CI 0.574 - 11.67) after surgery. Deltoid reflection (p=0.068), age (p=0.466), sex (p=0.936), glenoid graft (p=0.091), prosthesis manufacturer (p=0.382) and preop VAS score (p=0.362) were not of influence.

DISCUSSION

Results of this study show an extended deltopectoral approach for RSA is safe. Selected reflection of the anterior deltoid muscle improved exposure and prevents anterior deltoid muscle injury followed by re-attachment. Patients had similar functional scores preop and at 24 months compared to a comparative group. Furthermore, ultrasound evaluation showed intact re-attachments.

Joint-line medialization after anatomical total shoulder replacement requires more rotator cuff activity to preserve joint stability

BACKGROUND

The biomechanical effects of joint-line medialization during shoulder surgery are poorly understood. It was therefore the purpose of this study to investigate whether medialization of the joint line especially associated with total shoulder arthroplasty leads to changes in the rotator cuff muscle forces required to stabilize the arm in space.

METHODS

A validated computational 3-D rigid body simulation model was used to calculate generated muscle forces, instability ratios, muscle-tendon lengths and moment arms during scapular plane elevation. Measurements took place with the anatomical and a 2 mm and 6 mm lateralized or medialized joint line.

RESULTS

When the joint line was medialized, increased deltoid muscle activity was recorded throughout glenohumeral joint elevation. The rotator cuff muscle forces increased with medialization of the joint line in the early phases of elevation. Lateralization of the joint line led to higher rotator cuff muscle forces after 52° of glenohumeral elevation and to higher absolute values in muscle activity. A maximum instability ratio of >0.6 was recorded with 6 mm of joint-line medialization.

CONCLUSION

In this biomechanical study, medialization and lateralization of the normal joint line during total shoulder arthroplasty led to substantial load changes on the shoulder muscles used for stabilizing the arm in space. Specifically, medialization does not only lead to muscular shortening but also to increased load on the supraspinatus tendon during early arm elevation, the position which is already most loaded in the native joint.

Supracondylar Humeral Fractures: An Audit of the Frequency of Bi-columnar Fixation and Intra-articular Wire Placement

Introduction For supracondylar humeral (SCH) fractures, biomechanical studies suggest the most stable wire configuration achieves bi-columnar fixation. Achieving medial column fixation using lateral-entry-only wires may require an intracapsular entry point. The aim of this study was to identify the rate of bi-columnar fixation achieved in our department when treating SCH fractures with percutaneous wire fixation. A secondary aim was to identify the rate of placement of an intra-articular wire. Further aims were to examine if failure to achieve bi-columnar fixation was associated with an increased loss of fixation and whether the placement of an intra-articular wire resulted in any cases of deep infection or septic arthritis. Material and methods All Gartland type 3 supracondylar humeral fractures, June 2014 to December 2016, were retrospectively identified. Intra-operative films were reviewed to determine bi-columnar fixation and the presence/absence of an intra-articular wire. Loss of reduction requiring revision and post-operative infections were determined from the electronic patient record. Results Of 49 supracondylar fractures identified, 42 were fixed with lateral-entry only wires (24 with two wires and 18 with three wires), and seven were fixed with medial/lateral cross wires (four with one lateral wire, two with two wires, and one with three wires). Bi-columnar fixation was achieved in 41/49 cases (84%). All cases where bi-columnar fixation was not achieved were fixed with lateral-entry-only wires. One out of 49 fractures (2%) required the revision of fixation at 10 days due to loss of reduction. In this case, the initial fixation was with two lateral-entry-only wires, without bi-columnar fixation. An intra-articular wire was present in 44 out of 49 cases (90%). One out of 49 cases (2%) had a superficial wound infection. There were no cases of deep infection or septic arthritis. Conclusion In our department, the rate of bi-columnar fixation was high and, in this group, no cases required revision fixation. One of eight cases judged to not have bi-columnar fixation initially, required revision due to loss of fixation. We contend that bi-columnar fixation generally achieves a stable wire configuration even using lateral-entry-only wires for SCH fractures. The rate of intra-articular wire placement was high; however, infection rates were low with no cases of septic arthritis.

Osteoblast response to disordered nanotopography

The ability to influence stem cell differentiation is highly desirable as it would help us improve clinical outcomes for patients in various aspects. Many different techniques to achieve this have previously been investigated. This concise study, however, has focused on the topography on which cells grow. Current uncemented orthopaedic implants can fail if the implant fails to bind to the surrounding bone and, typically, forms a soft tissue interface which reduces direct bone contact. Here, we look at the effect of a previously reported nanotopography that utilises nanodisorder to influence mesenchymal stromal cell (as may be found in the bone marrow) differentiation towards bone and to also exert this effect on mature osteoblasts (as may be found in the bone). As topography is a physical technique, it can be envisaged for use in a range of materials such as polymers and metals used in the manufacture of orthopaedic implants.

Femoro Patella Vialla patellofemoral arthroplasty: An independent assessment of outcomes at minimum 2-year follow-up

AIM: To determine outcomes using the Femoro-Patella Vialla (FPV) arthroplasty and if there is an ideal patient for this implant.

METHODS: A total of 41 FPV patellofemoral joint replacements were performed in 31 patients (22 females, 9 males, mean age 65 years). Mean follow-up was 3.2 years (minimum 2 years). Radiographs were reviewed preoperatively and postoperatively. We assessed whether gender, age, previous surgery, patella atla or trochlear dysplasia influenced patient satisfaction or patient functional outcome.

RESULTS: The median Oxford Knee Score was 40 and the median Melbourne Patellofemoral Score was 21 postoperatively. Seventy-six percent of patients were satisfied, 10% unsure and 14% dissatisfied postoperatively. There was no radiological progression of tibiofemoral joint arthritis, using the Ahlback grading, in any patient. One patient, who was diagnosed with rheumatoid arthritis postoperatively, underwent revision to total knee replacement. There were no intraoperative lateral releases and no implant failures. Gender, age, the presence of trochlear dysplasia, patella alta or bilateral surgery did not influence patient outcome. Previous surgery did not correlate with outcome.

CONCLUSION: In contrast to the current literature, the FPV shows promising early results. However, we cannot identify a subgroup of patients with superior outcomes.

Actinobacillus hominis osteomyelitis: First reported case in the English language medical literature

Introduction:

Actinobacillus hominis is currently a rarely reported pathogen. It has previously been associated with respiratory tract infections and bacteraemia in debilitated patients. However, under-reporting may occur due to misidentification by commonly used laboratory bacterial identification systems. This case is, to the best of our knowledge, the first reported case of A. hominis osteomyelitis in the English language medical literature.

Case presentation:

A 37-year-old male presented with a painful foot. He had no previous foot problems, history of injury or animal contact. Osteomyelitis was confirmed by magnetic resonance imaging (MRI), and blood cultures were positive for Gram-variable bacilli. The organism was identified initially as Pasteurella pneumotropica by the local routine diagnostic laboratory and as a Pasteurella species by the UK National Reference Laboratory (Colindale, London, UK), using standard operating procedures at the time. It was finally identified as an A. hominis using 16S rRNA gene sequence analysis. Difficulties in the accurate identification of this organism remain current, as other biochemical identification systems have also resulted in misidentifications. The patient refused admission and intravenous antibiotics. He was successfully treated using an 8-week course of oral ciprofloxacin and amoxicillin based on antibiotic disc susceptibility testing resulting in clinical, serological and radiological resolution.

Conclusion:

Laboratories should maintain a high index of suspicion for A. hominis as several commonly used bacterial identification systems may not accurately identify the organism. Colonial morphology and absence of animal contact should prompt consideration of this organism in appropriate clinical situations. Oral ciprofloxacin and amoxicillin treatment was successful in this case.

Scanning electron microscopical observation of an osteoblast/osteoclast co-culture on micropatterned orthopaedic ceramics

In biomaterial engineering, the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. On contact with an implant, bone marrow-derived mesenchymal stromal cells demonstrate differentiation towards bone forming osteoblasts, which can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics. The purpose of this study was to establish a co-culture of bone marrow-derived mesenchymal stromal cells with osteoclast progenitor cells and to observe the response to micropatterned zirconia toughened alumina ceramics with 30 µm diameter pits. The aim was to establish whether the pits were specifically bioactive towards osteogenesis or were generally bioactive and would also stimulate osteoclastogenesis that could potentially lead to osteolysis. We demonstrate specific bioactivity of micropatterns towards osteogenesis, with more nodule formation and less osteoclastogenesis compared to planar controls. In addition, we found that that macrophage and osteoclast-like cells did not interact with the pits and formed fewer full-size osteoclast-like cells on the pitted surfaces. This may have a role when designing ceramic orthopaedic implants.

Primary arthroscopic stabilization for a first-time anterior dislocation of the shoulder. A randomized, double-blind trial

BACKGROUND

Anterior dislocation of the glenohumeral joint in younger patients is associated with a high risk of recurrence and persistent functional deficits. The aim of this study was to assess the efficacy of a primary arthroscopic Bankart repair, while controlling for the therapeutic effects produced by the arthroscopic intervention and joint lavage.

METHODS

In a single-center, double-blind clinical trial, eighty-eight adult patients under thirty-five years of age who had sustained a primary anterior glenohumeral dislocation were randomized to receive either an arthroscopic examination and joint lavage alone or together with an anatomic repair of the Bankart lesion. Assessment of the rate of recurrent instability, functional outcome (with use of three scores), range of movement, patient satisfaction, direct health-service costs, and treatment complications was completed for eighty-four of these patients (forty-two in each group) during the subsequent two years.

RESULTS

In the two years after the primary dislocation, the risk of a further dislocation was reduced by 76% and the risk of all recurrent instability was reduced by 82% in the Bankart repair group compared with the group that had arthroscopy and lavage alone. The functional scores were also better (p < 0.05), the treatment costs were lower (p = 0.012), and patient satisfaction was higher (p < 0.001) after arthroscopic repair. The improved functional outcome appeared to be mediated through the prevention of instability since the functional outcome in patients with stable shoulders was similar, irrespective of the initial treatment allocation. The patients who had a Bankart repair and played contact sports were also more likely to have returned to their sport at two years (relative risk = 3.4, p = 0.007).

CONCLUSIONS

Following a first-time anterior dislocation of the shoulder, there is a marked treatment benefit from primary arthroscopic repair of a Bankart lesion, which is distinct from the so-called background therapeutic effect of the arthroscopic examination and lavage of the joint. However, primary repair does not appear to confer a functional benefit to patients with a stable shoulder at two years after the dislocation.

Structural principles and amorphouslike thermal conductivity of Na-doped Si clathrates

The postulated low thermal conductivity and the possibility of altering the electronic conductivity of metal-doped clathrates with semiconducting host elements have stimulated great interest in exploring these compounds as promising thermoelectric materials. The electronic and thermal properties of the prototypical Na xSi (46) system are studied in detail here. It is shown that, despite the fact that the Na/Si clathrate is metallic, its thermal conductivity resembles that of an amorphous solid. A theoretical model is developed to rationalize the structural stability of the peculiar structural topology, and a general scheme for rational design of high efficiency thermoelectric materials is presented.