Tibiofemoral contact biomechanics following meniscocapsular separation and repair

Meniscocapsular separations are often seen in knees with other intra-articular pathology. The consequences of these tears with regard to knee contact mechanics are currently unknown, and the biomechanical advantages of repair have not been measured. We hypothesize that tears to the meniscocapsular junction will cause an increase in tibiofemoral contact pressure and a decrease in contact area, with a return to more normal conditions after repair. 10 fresh-frozen cadaver knees each underwent 10 cycles of axial compressive loading in full extension under three different testing conditions: intact, meniscocapsular separation, and repair. A pressure sensor matrix was inserted into the medial joint space and used to measure magnitude and location of contact pressure and area. Mean contact pressure increased from 0.80±0.17 MPa in the intact knee to 0.88±0.19 MPa with separation, with a decrease to 0.78±0.14 MPa following repair. Peak pressures followed a similar trend with 2.59±0.41, 3.03±0.48, and 2.84±0.40 MPa for the same three groups, respectively. While none of the changes seen was statistically significant, even these small changes would potentially create degenerative changes at the articular surface over prolonged (i. e., months or years) standing, walking, and activity in the unrepaired state.

Diagnosis and treatment of shoulder injuries in the throwing athlete: the role of thermal-assisted capsular shrinkage

The treatment of the throwing athlete is complex. Many factors enter into the decision regarding the nature and timing of appropriate intervention. Because of the nature of the mechanical aspects of the throwing motion, increased external rotation (overrotation) is often necessary to throw at a highly competitive level. This increased motion is associated with acquired increased glenohumeral laxity which, by itself, is generally not problematic. However, in the athlete with an overuse-type shoulder injury such as a SLAP lesion or a partial-thickness undersurface tear of the rotator cuff (internal impingement), it is perhaps the increase in glenohumeral laxity that allows such pathology to occur. A careful history and physical examination are important to determine the nature of the injury and the amount of laxity that may be present. Currently, we believe that addressing the capsular laxity arthroscopically at the same time that the intra-articular pathology is addressed is the best form of treatment for these athletes, and affords them the best chance of returning to competition at the same or higher level. Obviously, further follow-up is necessary to determine the long-term results of such treatment.

Vascular pathology in the throwing athlete

Vascular pathology in the upper extremity of a throwing athlete comprises a spectrum of serious disorders apt to threaten the patient's career and the viability of the involved parts. Such pathology includes digital vessel thrombosis, proximal thrombosis with distal embolization, vessel aneurysm, and vessel compression, such as in thoracic outlet syndrome and quadrilateral space syndrome. This article provides a description of vascular disorders prone to result from sports activities and a review of published data relevant to throwing athletes. Recognition of vascular compromise as a cause for dead arm syndrome or painful digital dysfunction among athletes is essential to prevent the grave consequences of progressive ischemia.

Chance fracture after pedicle screw fixation. A case report

STUDY DESIGN

A case of a Chance fracture through an instrumented pedicle is presented. The radiographic and intraoperative findings and management of this complication are reported.

OBJECTIVE

To increase awareness of the complications of transpedicular screw fixation and to suggest a form of management of this unusual complication.

SUMMARY OF BACKGROUND DATA

To the authors' knowledge, this is the first reported case of such a vertebral fracture occurring after pedicle screw fixation.

METHODS

A 44-year-old man with athetoid cerebral palsy and a progressive thoracic kyphosis sustained a Chance fracture at the caudal end of the segmental instrumentation construct.

RESULTS

Surgical intervention, including fracture reduction and extension of the instrumented fusion to the pelvis, provided effective restoration of physiologic sagittal alignment.

CONCLUSION

Chance fracture after pedicle screw fixation can be successfully managed with surgical intervention.