Osteoarthritis (OA) is a major cause of suffering for millions of people. Investigating the disease directly on humans may be challenging. The aim of the present study is to investigate the advantages and limitations of the animal models currently used in OA research. The animal models are divided into induced and spontaneous. Induced models are further subdivided into surgical and chemical models, according to the procedure used to induce OA. Surgical induction of OA is the most commonly used procedure, which alters the exerted strain on the joint and/or alter load bearing leading to instability of the joint and induction of OA. Chemical models are generated by intra-articular injection of modifying factors or by systemically administering noxious agents, such as quinolones. Spontaneous models include naturally occurring and genetic models. Naturally occurring OA is described in certain species, while genetic models are developed by gene manipulation. Overall, there is no single animal model that is ideal for studying degenerative OA. However, in the present review, an attempt is made to clarify the most appropriate use of each model.

Recurrent dislocation, subluxation and functional instability due to patellofemoral pain might be present in 30 % to 60 % of patients managed non-operatively for posttraumatic patella instability. Disruption of the capsule, medial patella retinaculum and/or vastus medialis obliquus have been associated with recurrent patella instability but recently the medial patellofemoral ligament (MPFL) has been recognised as the most important ligamentous stabiliser preventing lateral dislocation of the patella. Many nonanatomical surgical techniques for the treatment of recurrent patellar dislocation have been described in the literature. These procedures alter the pre-morbid patella mechanics by several principles, including the release of tight lateral ligaments, tensioning of loose medial structures and distal realignment of the extensor mechanism or a combination of these. Very few address the principle site of pathology in patella dislocation, i.e., the torn MPFL. The outcomes are inconsistent and many studies have reported recurrent dislocations and patellofemoral pain and arthritis in up to 40 %. We describe a simple technique of MPFL reconstruction using a single hamstring tendon graft which is passed through the medial intermuscular septum at the adductor's magnus insertion and is fixed to the superomedial pole of the patella. A comprehensive review of the existing techniques of MPFL reconstruction using semitendinosus tendon autografts is also provided.

Avulsion of the tibial tuberosity is a rarely reported fracture. It is mainly considered as an athletic injury accounting for less than 3% of all epiphyseal lesions. In this study, we hypothesized that the use of tension band wiring as a supplement of the internal fixation for the avulsion fractures of the tibial tuberosity would lead the adolescent athletes to a more effective rehabilitation program and an earlier resumption of their previous activity level. Ten patients were treated in our department over a period of 11 years (1985-1995). Operative treatment was thought necessary for all our cases due to tibial tuberosity displacement. Open reduction and internal fixation in combination with tension band wiring was used. The result in all cases was that the reduction was maintained intact and the fracture united. The functional results were excellent, and all patients returned to their previous athletic activities. Our conclusion is that the combination of internal fixation and tension band wiring for avulsion fractures of the tibial tuberosity seems to be more effective and advantageous than conservative or other surgical methods. Avoiding the need of external support and allowing early joint motion, the method described prevents serious quadriceps atrophy, allowing the young athletes to return earlier to their previous sport activities.

Data suggest anabolic steroids may enhance production of bioartificial tendons and rotator cuff tendon healing in vitro. More research is necessary before such clinical use is recommended.

In prophylactic stages salmon calcitonin seemed to inhibit the progression of osteoarthritis by increasing the layers of hyaline cartilage, restoring the cellular metabolism, and decreasing the volume of osteophytes. In therapeutic stages, the hormone had a healing effect by decreasing the subchondral cysts, regenerating the hyaline cartilage and restoring cellular metabolism. Both macroscopic and histological findings of this study supported the biochemical results of previous studies showing the therapeutic effect of calcitonin on osteoarthritis.