Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis.

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

[Femoroacetabular impingement: rehabilitation and return to sport]. / Rééducation des conflits fémoro-acétabulaires et retour au sport.

Femoroacetabular impingements (FAI) are quite frequent among young athletes. An early detection is essential in order to prevent more labral and cartilage damage. Conservative treatment should not focus on forcing the full range of motion but on restoring a good muscle balance around the joint and a better lower limb dynamic stability and control. The patient should be educated to master the end of hip range of motion during his activities. If the outcome is not satisfactory, a surgical treatment is offered. The post-operative treatment protocol is tailored to the type of repair, following several stages, from neuromuscular control to strengthening up to the return to sport. FAI prevention should be more studied in order to protect the hip of the growing athlete.

[Athletic pubalgia and hip impingement]. / Pubalgie et confit fémoro-acétabulaire.

Athletic pubalgia is a painful and complex syndrom encountered by athletes involved in pivoting and cutting sports such as hockey and soccer. To date, there is no real consensus on the criteria for a reliable diagnostic, the different investigations, and the appropriate therapy. Current literature underlines intrinsic and extrinsic factors contributing to athletic pubalgia. This review article reports upon two novelties related to the issue: the importance and efficience of prevention program and the association of femoro-acetabular impingement with the pubalgia.

[Deleterious effects of smoking on the musculoskeletal system]. / Effets délétéres du tabagisme sur l'appareil musculo-squelettique.

Tobacco smoking has important negative effects on the musculoskeletal system: decrease of bone mineral density, increase of the risk of injury, illness, and perioperative complications such as fracture-healing complications and wound complications. Orthopaedic surgeons should inform all patients of the increased risks associated with active smoking in the perioperative period and should encourage them to quit smoking four to eight weeks in advance of the proposed procedure.

[Return to sport after anterior cruciate ligament reconstruction]. / Retour au sport après reconstruction du ligament croisé antérieur.

Despite continuous advances in techniques for anterior cruciate ligament reconstruction (ACLR), return to play (RTP) after surgery remains a challenge. More than one-third of the patients are unable to return to their preinjury sport level, for most because of a fear to sustain another injury. And when a RTP is attempted, up to 20% will tear their graft and a similar % will sustain an ACL tear on the opposite side. We believe that these failures result from an incomplete recovery. Based on a literature review and on our experience, we suggest 6 objective criteria to allow a safer RTP. They rely on laxity, strength, neuromuscular function, and psychological evaluations. Rehabilitation after ACLR should focus on the deficits identified by these tests and on they specific needs of the sport that the athlete plans to return to.

[Autologous chondrocyte implantation for focal cartilage lesions: state of the art in 2007]. / Implantation de chondrocytes autologues pour les lésions cartilagineuses focales: le point en 2007.

Autologous chondrocyte implantation (ACI) is a frequently used procedure for full-thickness cartilage lesions in the knee joint. However, to date, there are just a few prospective, randomized clinical studies and most publications are case series on small and heterogenic cohorts with short-term follow-up. To date, ACI is a surgical treatment option for single traumatic lesions on the distal femur in young active subjects with a recent lesion. Lesion size should be between 3 and 8 cm2, < 6 mm in depth, tidemark preserved without penetration of the subchondral bone. Absolute contraindications for ACI include osteoarthrosis, kissing lesions, lesions size greater than 10 cm2 or deeper than 8 mm, ligament instability, partial or total meniscectomy, axis malalignment > 5. Further studies are mandatory to determine the precise indications to the technique and to show its superiority on the established treatment of chondral lesions.

[Plasticity of striated skeletal muscle: training effect and perspectives]. / Plasticité du muscle strié squelettique: effet de l'entraînement et perspectives.

The muscle's wide array of functional characteristics is mediated by the existence of fiber types, differing one from the other in terms of contractile and metabolic protein isoforms content. Numerous classification systems have evolved, describing the muscle's physical, architectural and metabolic characteristics. Nevertheless, it appears that those characteristics assemble in more or less independent modules, excluding the development of a generalized classification of muscle fiber types. The discovery of several mechanisms allowing for the muscle to adapt to training or other changes opens new interventional perspectives regarding sport performances, as well as the maintenance of an adequate musculature in patients.

[Patella dislocation]. / La luxation de la rotute.

Patella dislocation is a classical injury affecting teenagers. In 2/3 of cases, it occurs in sports activities. It is often a benign trauma which happens in a patello-femoral dysplasia context, leading to dislocation and reccurence if nothing is done to correct the defaults. Radiographic and scanner examinations allow to measure the dysplasia parameters and think about its correction. With MRI documentation, capsulo-ligamentous and cartilaginous lesions can be identified and their surgical repair can be discussed. When the dislocation occurs in a normal anatomical context, conservative therapy is still indicated.

Use of muscle cells to mediate gene transfer to the bone defect.

Segmental bone defects and nonunions are relatively common problems facing all orthopaedic surgeons. Osteogenic proteins, i.e., BMP-2, can promote bone healing in segmental bone defects. However, a large quantity of the human recombinant protein is needed to enhance the bone healing potential. Cell mediated gene therapy in the bone defect can allow a sustained expression of the osteogenic proteins and further enhance bone healing. Muscle cells can be easily isolated and cultivated, and they are known to be an efficient gene delivery vehicle to muscle and nonmuscle tissues. Furthermore, they are capable of transforming into osteoblasts when stimulated by BMP-2. Thus, the utilization of muscle cells as the gene delivery vehicle to a bone defect would be an important step in establishing a less invasive treatment for non-unions and segmental bone defects. Muscle cells were transduced when the adenoviral-lacZ vector and injected into the bone defect and the muscles surrounding the defect. Expression of the marker gene was visualized 7 days after the injection, both macroscopically and microscopically, using lacZ histochemistry. The lacZ expressing cells in the defect tissue were also stained for desmin, a muscle specific marker, indicating the presence of muscle cells that have fused into myofibers in this nonmuscle bone defect area. With successful myoblast mediated gene delivery into the segmental bone defect, future experiments would focus on delivering viral vectors expressing osteogenic proteins to eventually improve bone healing postinjury.

Direct-, fibroblast- and myoblast-mediated gene transfer to the anterior cruciate ligament.

The anterior cruciate ligament (ACL) has poor capabilities of healing. Maturation or "ligamentization" of the ACL following autograft or allograft reconstruction has been found slow and remains under investigation. In vitro and in vivo studies have shown that platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), and epidermal growth factor (EGF) have the potential to improve ligament healing. Gene therapy approaches may represent a new alternative in delivering these specific growth factors to the ACL. The aim of this study was to investigate the feasibility of three different gene therapy approaches (direct-, fibroblast-, and myoblast-mediated gene transfer) to the ACL. Rabbit myoblasts and ACL-fibroblasts were transduced with 5 x 10(7) recombinant adenoviral particles carrying the LacZ reporter gene (MOI = 50). Myoblasts and fibroblasts (1 x 10(6)) were each injected into the right ACL of 10 adult rabbits; direct injection of 5 x 10(7) adenoviral particles was performed in 10 other rabbits. The left side was used as sham. The beta-galactosidase production was revealed using the LacZ histochemical technique. The transduced fibroblasts and myoblasts were found in the ligament tissue and in the synovial tissue surrounding the ACL at 4, 7, 14, and 21 days postinjection. The myoblasts fused and formed myotubes in the ligament. The direct approach also allowed the transfer of the marker gene in the ligament at 4, 7, 21, and 42 days postinjection. X-gal staining revealed no expression of beta-galactosidase in the sham ligament. The presence of cells expressing the marker gene in the ACL opens up the possibility of delivering proteins (i.e., PDGF, TGF-beta, and EGF) capable of improving ACL healing and graft maturation. Furthermore, engineered myoblasts may mediate and accelerate the intraligament neovascularization. This new technology based on gene therapy and tissue engineering may allow a persistent expression of selected growth factors to enhance ACL healing following injury.

Development of approaches to improve the healing following muscle contusion.

Muscle injuries are a challenging problem in traumatology, and the most frequent occurrence in sports medicine. Muscle contusions are among the most common muscle injuries. Although this injury is capable of healing, an incomplete functional recovery often occurs, depending on the severity of the blunt trauma. We have developed an animal model of muscle contusion in mice (high energy blunt trauma) and characterized the muscle's ability to heal following this injury using histology and immunohistochemistry to determine the level of muscle regeneration and the development of scar tissue. We have observed a massive muscle regeneration occurring in the first 2 wk postinjury that is subsequently followed by the development of muscle fibrosis. Based on these observations, we propose that the enhancement of muscle growth and regeneration, as well as the prevention of fibrotic development, could be used as approach(es) to improve the healing of muscle injuries. In fact, we have identified three growth factors (bFGF, IGF-1, and NGF) capable of enhancing myoblast proliferation and differentiation in vitro and improving the healing of the injured muscle in vivo. Furthermore, the ability of adenovirus to mediate direct and ex vivo gene transfer of beta-galactosidase into the injured site opens possibilities of delivering an efficient and persistent expression of these growth factors in the injured muscle. These studies should help in the development of strategies to promote efficient muscle healing with complete functional recovery following muscle contusion.

Myoblast-mediated gene transfer to the joint.

Several genetic and acquired pathologic conditions of the musculoskeletal system, such as arthritis and damage to ligament, cartilage, and meniscus, may be amenable to gene therapy. Even though ex vivo gene transfer with synovial cells has been shown to deliver genes encoding for anti-arthritic proteins into the rabbit knee joint, its success has been limited by a transient transgene expression. In this study, data were investigated regarding the use of muscle cells as an alternative gene-delivery vehicle to the joint in newborn rabbit and adult severe combined immunodeficiency mice. We demonstrated that myoblasts were transduced more efficiently than synovial cells with use of the same adenoviral preparation in vitro. After intra-articular injection, the engineered muscle cells adhered to several structures in the joint, including the ligament, capsule, and synovium. In addition, myoblasts fused to form many post-mitotic myotubes and myofibers at different locations of the joint of the newborn rabbit 5 days after the injection. In the knee of the adult mouse, myoblasts fused and expressed the reporter gene for at least 35 days after the injection. The presence of post-mitotic myofibers in the knee joint raises the possibility of long-term expression of the secreted protein. Currently, numerous tissues in the joint (ligament, meniscus, and cartilage) have poor intrinsic healing capacity and frequently need surgical corrections. A stable gene-delivery vehicle to the joint producing proteins that ameliorate these different musculoskeletal conditions may change the clinical implications of these pathologies.

Subtalar subluxation in ballet dancers.

Ankle injuries frequently occur in dancers. Among these injuries, only a few cases of talar subluxation have been reported in the literature. In our series, we diagnosed and treated 25 subtalar subluxations over a 1-year period in the Ballet Béjart Lausanne company. The subluxations occurred after a grand plie on pointes or at the landing of a jump on demi-pointes, without any mechanism of ankle sprain. The dancer usually noted a sudden and sharp pain in the talonavicular joint and hindfoot with a feeling of "forward displacement" of the foot. At palpation, the talonavicular ligament, the anterior talofibular ligament, and the posteromedial part of the subtalar joint were painful. A limitation of the ankle extension and a clear hypomobility of the subtalar joint were noted. Under the effect of shearing forces on the midtarsal joint, a posteromedial subtalar subluxation occurred. Treatment consisted of a manipulation that reduced the subluxation. Continuous taping, which locks the talonavicular joint in the anterior direction, was recommended for 6 weeks. Dancing could be resumed in a swimming pool after 2 weeks, and on the ground after 3 to 4 weeks. We found that subluxation could recur, and that it could eventually become chronic.

Current trends in anterior cruciate ligament reconstruction. Part II. Operative procedures and clinical correlations.

Surgical management of the anterior cruciate ligament-deficient knee has evolved from primary repair to extracapsular augmentation to anterior cruciate ligament reconstruction using biologic tissue grafts. The technique of anterior cruciate ligament reconstruction has improved over the last few decades with the aid of knowledge gained from basic science and clinical research. The biology and biomechanics of anterior cruciate ligament reconstruction were analyzed in the previously published first part of this article. In this second part, current operative concepts of anterior cruciate ligament reconstruction as well as clinical correlations are discussed. The latest information regarding anterior cruciate ligament reconstruction is presented with a goal of demonstrating the correlation between the application of basic science knowledge and the improvement of clinical outcomes.

Suturing versus immobilization of a muscle laceration. A morphological and functional study in a mouse model.

Muscle laceration remains a difficult problem for orthopaedic surgeons. Despite many studies related to the muscle's ability to regenerate after muscle degeneration, very few reports are available regarding structural and functional recovery after skeletal muscle laceration. We developed an animal model of muscle laceration in mice, where the gastrocnemius muscles were reproducibly transected. We compared the effect of a surgical repair versus a short period of immobilization (5 days) on the muscle healing. The natural course of muscle recovery was monitored at several points after injury using histologic, immunohistochemical, and functional testing. In the injured muscle, we observed a high number of regenerating myofibers and development of fibrotic scar tissue. Suturing the lacerated muscle immediately after injury promoted better healing of the injured muscle and prevented the development of deep scar tissue in the lacerated muscle; conversely, immobilization resulted in slower muscle regeneration and the development of a large area of scar tissue. Tetanus strength 1 month after injury was 81% of control muscles for the sutured muscles, 35% for the lacerated muscles with no treatment, and 18% for the immobilized muscles. Based on this study, suturing a muscle laceration with a modified Kessler stitch results in the best morphologic and functional healing.

Growth factors improve muscle healing in vivo.

Injury to muscles is very common. We have previously observed that basic fibroblast growth factor (b-FGF), insulin growth factor type 1 (IGF-1) and nerve growth factor (NGF) are potent stimulators of the proliferation and fusion of myoblasts in vitro. We therefore injected these growth factors into mice with lacerations of the gastrocnemius muscle. The muscle regeneration was evaluated at one week by histological staining and quantitative histology. Muscle healing was assessed histologically and the contractile properties were measured one month after injury. Our findings showed that b-FGF, IGF and to a less extent NGF enhanced muscle regeneration in vivo compared with control muscle. At one month, muscles treated with IGF-1 and b-FGF showed improved healing and significantly increased fast-twitch and tetanus strengths. Our results suggest that b-FGF and IGF-1 stimulated muscle healing and may have a considerable effect on the treatment of muscle injuries.