International Orthopaedics

A clavicle hook plate is a simple and effective method for treating acromioclavicular dislocation and distal clavicle fractures. However, subacromial osteolysis and peri-implant fractures are complicated for surgeons to manage. This study uses finite element analysis (FEA) to investigate the post-implantation biomechanics of clavicle hook plates with different hook angles. This FEA study constructed a model with a clavicle, acromion, clavicle hook plate, and screws to simulate the implantation of clavicle hook plates at different hook angles (90°, 95°, 100°, 105°, and 110°) for treating acromioclavicular joint dislocations. This study investigated the biomechanics of the acromion, clavicle, hook plate, and screws. A smaller hook angle increases the stress on the middle third of the clavicle. A larger hook angle increases the force exerted by the clavicle hook plate on the acromion. The screw at the most medial position on the plate generated the highest stress. The highest stress on the implanted clavicle hook plate was on the turning corner of the hook. A clavicle hook plate with different hook angles may induce different biomechanical behaviors in the clavicle and acromion. Orthopedic surgeons must select a suitable clavicle hook plate based on the anatomical structure of each patient.

The aim of this study was to determine whether or not detaching the biceps tendon from the glenoid after tenodesis performed with the inclusion of the biceps in the rotator cuff suture results in an improved outcome. From 1999 to 2001, 22 patients had an arthroscopic rotator cuff repair and associated biceps tendon lesions that were repaired with two new arthroscopic techniques of tenodesis incorporating the biceps tendon in the rotator cuff suture. Patients were randomised into one of two groups: tenodesis without tenotomy (group 1) and tenodesis with tenotomy (group 2). Preoperative and postoperative functions were assessed by means of a modified UCLA rating scale and shoulder ROM. The mean follow-up period was 47.2 months (range 36– 59). In group 1 (tenodesis without tenotomy), eight patients had an excellent postoperative score and three a good postoperative score. The UCLA rating system used for evaluation showed a statistically significant improvement from the preoperative average rating of 10.5 (5–15) to the postoperative average score of 33 (29–35) (P<0.05). In group 2 (tenodesis with tenotomy), the UCLA rating system used for evaluation showed a statistically significant improvement from the preoperative rating of 11.1 to the postoperative score of 32.9 (P<0.05). No statistically significant difference in the total UCLA scores was found when comparing the repairs performed with or without tenotomy. Follow-up results with regard to ROM were not different between the two groups, and the range of motion was improved in all measured directions. In this series, every patient qualified as having good to excellent results according to the UCLA score. This study suggests that there is no difference between detaching and not detaching the biceps after including it in the repair.

Tendinopathy is a major complication of diet-induced obesity. However, the effects of a high-fat diet (HFD) on tendon have not been well characterised. We aimed to determine: [1] the impact of a HFD on tendon properties and gene expression; and [2] whether dietary transition to a control diet (CD) could restore normal tendon health. Sprague–Dawley rats were randomised into three groups from weaning and fed either a: CD, HFD or HFD for 12 weeks and then CD thereafter (HF-CD). Biomechanical, histological and structural evaluation of the Achilles tendon was performed at 17 and 27 weeks of age. Tail tenocytes were isolated with growth rate and collagen production determined. Tenocytes and activated THP-1 cells were exposed to conditioned media (CM) of visceral adipose tissue explants, and gene expression was analysed. There were no differences in the biomechanical, histological or structural tendon properties between groups. However, tenocyte growth and collagen production were increased in the HFD group at 27 weeks. There was lower SOX-9 expression in the HFD and HF-CD groups at 17 weeks and higher expression of collagen-Iα1 and matrix metalloproteinase-13 in the HFD group at 27 weeks. THP-1 cells exposed to adipose tissue CM from animals fed a HFD or HF-CD had lower expression of Il-10 and higher expression of Il-1β. In this rodent model, a HFD negatively altered tendon cell characteristics. Dietary intervention restored some gene expression changes; however, adipose tissue secretions from the HF-CD group promoted an increased inflammatory state in macrophages. These changes may predispose tendon to injury and adverse events later in life.

The Vancouver Classification System (VCS) for assessing periprosthetic femoral fractures has become universally accepted. The Unified Classification System (UCS) has expanded upon and updated the VCS and applied treatment principles to all periprosthetic fractures. However, periprosthetic femoral fractures accompanied by stem fracture after hip arthroplasty were not classifiable under the original VCS or the UCS. Our new fracture pattern is based on the periprosthetic femoral fracture as well as stem fracture after hip arthroplasty, and its treatment is dependent upon the stability of the proximal portion of the fractured femoral prosthesis. We believe that our new fracture pattern, a supplement to the VCS and UCS, is useful in the establishment of a therapeutic strategy for periprosthetic femoral fractures.

Unicompartmental changes in the knee of a young athlete remains a difficult and controversial problem in orthopaedics. Excessive premature loading of articular cartilage, most often the result of a knee injury, has been shown to result in increased degenerative changes and pain in the younger patient. Instability may also contribute to the degeneration of cartilage and must therefore be considered in the treatment of osteoarthritis in the young adult. High tibial osteotomy has been described as a treatment option for malalignment in the older, less active adult and has shown promising results in a younger, more active population. Osteotomies for instability are more controversial and should be considered in more complex injury patterns.

Coronal shear fractures of the distal humerus involving the capitellum and trochlea are rare injuries. Internal fixation with headless compression screws provides a stable construct facilitating early mobilisation. Our study aimed to identify the key determinants of both radiological and functional outcomes of patients with distal humerus coronal shear fractures treated with internal fixation. A retrospective analysis of 61 patients with distal humerus coronal shear fractures who were treated surgically was done. Demographics, fracture morphology, time to surgery, operative details such as surgical approach and implant used, quality of reduction, time to union, and associated complications from hospital records. Radiological outcomes were assessed using plain radiographs, and the functional outcomes were by Oxford Elbow Score (OES) and Mayo Elbow Performance Index (MEPI). Patients with anatomical reduction of the fracture had better functional outcomes and range of motion. The presence of posterior comminution of capitellum resulted in poorer outcomes (p = 0.03). Delayed presentation did not alter the outcome when the anatomical reduction was achieved. Myositis ossificans was noted in nine patients and non-union in five patients. Two patients developed avascular necrosis of the capitellum and arthritis of the elbow joint. Anatomical reduction and posterior comminution are the two key determinants of the functional outcome in these coronal shear fractures of the distal humerus. Early mobilisation following a stable fixation is crucial in achieving a good outcome.

The aim of the study was to compare primary total hip arthroplasty (THA) implantations between different countries in terms of THA number per inhabitant, age, and procedure type and to compare the survival curve including all THAs using hip arthroplasty registers. THA registers were compared between different countries with respect to the number of primary implantations per inhabitant and age, procedure type and survival curve. We performed a literature search for all national hip arthroplasty registers providing annual reports for 2009 or, if not available, a more recent period. The data from these reports were analysed in terms of number, age distribution and procedure type of primary THAs and survival curves. We identified nine hip arthroplasty registers, which comprised sufficient data to be included. A large variation was found in the annual number of primary THA implantations per inhabitant. The procedure type varied greatly as well, e.g. in Sweden 67 % are cemented THAs whereas in Emilia-Romagna (Italy) 89 % are cementless THAs. This study revealed large differences in terms of the annual number of primary THAs per inhabitant and primary THA procedure type across countries. These data can be used to rank local primary THA implantations within an international context.