Impingement syndrome

Pathologies de l'épaule du lanceur, du nageur, du pratiquant de sports de raquette : les lésions du tendon de la coiffe des rotateurs, en rapport avec un syndrome d'empiètement

Compression etiology in tendinopathy

Recent studies have emphasized that the etiology of tendinopathy is not as simple as was once thought. The etiology is likely to be multifactorial. Etiologic factors may include some of the traditional factors such as overuse, inflexibility, and equipment problems; however, other factors need to be considered as well, such as age-related tendon degeneration and biomechanical considerations as outlined in this article. More research is needed to determine the significance of stress-shielding and compression in tendinopathy. If they are confirmed to play a role, this finding may significantly alter our approach in both prevention and in treatment through exercise therapy. The current biomechanical studies indicate that certain joint positions are more likely to place tensile stress on the area of the tendon commonly affected by tendinopathy. These joint positions seem to be different than the traditional positions for stretching exercises used for prevention and rehabilitation of tendinopathic conditions. Incorporation of different joint positions during stretching exercises may exert more uniform, controlled tensile stress on these affected areas of the tendon and avoid stresshielding. These exercises may be able to better maintain the mechanical strength of that region of the tendon and thereby avoid injury. Alternatively, they could more uniformly stress a healing area of the tendon in a controlled manner, and thereby stimulate healing once an injury has occurred. Additional work will have to prove if a change in rehabilitation exercises is more efficacious that current techniques

Knee Stability Following Anterior Cruciate Ligament Rupture and Surgery: The Contribution of Irreducible Tibial Subluxation

Background: Knee stability after anterior cruciate ligament reconstruction is generally determined by measuring total anteroposterior tibial motion. In spite of a decrease in excessive anteroposterior tibial motion after anterior cruciate ligament reconstruction, problems can still develop. In the present study, we sought to define the tibiofemoral relationship more accurately with use of stress radiographs of human knees after anterior cruciate ligament rupture and after anterior cruciate ligament reconstruction. Methods: A previously described radiographic technique was used to evaluate the position of the tibia relative to the femur with the application of an anteriorly directed tibial force and subsequently with the application of a posteriorly directed tibial force. Tibial position and total tibial translation were calculated from these radiographs. In addition, KT-1000 measurements were obtained. Three groups of patients were studied: Group 1 included twenty-eight patients with an untreated anterior cruciate ligament rupture, Group 2 included nineteen patients who had undergone a clinically successful anterior cruciate ligament reconstruction, and Group 3 included twenty-five control subjects with normal knees. Results: KT-1000 testing showed that the average side-to-side differences in Group 1 (5.8 mm) and Group 2 (2.7 mm) were significantly different from that in Group 3 (0.8 mm) (p \u3c 0.01 and p \u3c 0.05, respectively). Stress radiographs showed that the average total tibial translation in Group 1 (9.8 mm) was significantly different from those in Group 2 (5.6 mm) and Group 3 (4.3 mm) (p \u3c 0.05 and p \u3c 0.001, respectively). Within Group 1, knees with radiographic signs of osteoarthritis were more stable, with an average total tibial excursion of 6.8 mm. The improved stability of the reconstructed knees in Group 2 and the osteoarthritic knees in Group 1 was not entirely the result of decreased anterior tibial translation; it was, in part, due to an irreducible anterior subluxation of the tibia. A posteriorly directed stress in these knees did not reduce the tibia to the anatomic position relative to the femur; the osteoarthritic knees in Group 1 were 9.9 mm short of full reduction and the knees in Group 2 were 3.1 mm short of full reduction (p \u3c 0.01) Conclusions: Irreducible tibial subluxation can be present in the knee following surgical reconstruction of the anterior cruciate ligament. Osteoarthritic changes following an untreated anterior cruciate ligament rupture are also associated with uncorrectable tibial subluxation along with a decrease in instability. The irreducible tibial subluxation could explain why osteoarthritic changes still may develop in stable, reconstructed knees in spite of the improved stability. Currently used arthrometric measurements, such as KT-1000 scores, do not measure this phenomenon. Level of Evidence: Therapeutic study, Level III-2 (retrospective cohort study)

Biomechanics and pathophysiology of overuse tendon injuries: ideas on insertional tendinopathy

Tendons behave viscoelastically and exhibit adaptive responses to conditions of increased loading and disuse. High-resolution, real-time ultrasound scanning confirms the applicability of these findings in human tendons in vivo. In addition, recent biomechanical studies indicate that strain patterns in tendons may not be uniform, as tendons show stress-shielded areas and areas subjected to compressive loading at the enthesis. These areas correspond to the sites where tendinopathic characteristics are typically seen. This indicates that some tendinopathies may, paradoxically, be considered as 'underuse' lesions despite the common beliefs that they are overuse injuries. Classic inflammatory changes are not frequently seen in chronic athletic tendon conditions and histopathology features in tendinopathic tendons are clearly different from normal tendons, showing an exaggerated dysfunctional repair response. Tendinopathies are traditionally considered overuse injuries, involving excessive tensile loading and subsequent breakdown of the loaded tendon. Biomechanical studies show that the strains within the tendons near their insertion site are not uniform. If the material properties are similar throughout the tendon, forces transferred through the insertion site preferentially load the side of the tendon that is usually not affected initially in tendinopathy. In that case, the side affected by tendinopathy is generally 'stress shielded'. Thus, the presence of differential strains opens the possibility of alternative biomechanical explanations for the pathology found in these regions of the tendon. The traditional concept of tensile failure may not be the essential feature of the pathomechanics of insertional tendinopathy. Certain joint positions are more likely to stress the area of the tendon commonly affected by tendinopathy. Incorporating different joint position exercises may exert more controlled stresses on these affected areas of the tendon, possibly allowing better maintenance of the mechanical strength of that tendon region and, therefore, prevent injury. Such exercises could stress a healing area of the tendon in a controlled manner and thus stimulate healing once an injury has occurred. Additional work is needed to prove whether such principles should be incorporated in current rehabilitation techniques

Intramedullary screw fixation of Jones fractures: analysis of failure

La fracture de Jones est une fracture par arrachement de la base du 5ème métatarsien. Le but de cette étude est de determiner les causes des échecs des thérapies chirurgicales, chez 15 athlètes, dont 6 sont des athlètes de haut niveau