Rehabilitation after anterior cruciate ligament (ACL) reconstruction has focused over the past decade on closed kinetic chain (CKC) exercises due to presumably less strain on the graft than with isokinetic open kinetic chain exercises (OKC); however, recent reports suggest that there are only minor differences in ACL strain values between some CKC and OKC exercises. We studied anterior knee laxity, thigh muscle torque, and return to preinjury sports level in 44 patients with unilateral ACL; group 1 carried out quadriceps strengthening only with CKC while group 2 trained with CKC plus OKC exercises starting from week 6 after surgery. Anterior knee laxity was determined with a KT-1000 arthrometer; isokinetic concentric and eccentric quadriceps and hamstring muscle torque were studied with a Kin-Com dynamometer before and 6 months after surgery. At an average of 31 months after surgery the patients answered a questionnaire regarding their current knee function and physical activity/sports to determine the extent and timing of their recovery. No significant differences in anterior knee laxity were noted between the groups 6 months postsurgery. Patients in group 2 increased their quadriceps torque significantly more than those in group 1, but no differences were found in hamstring torque between the groups. A significantly higher number of patients in group 2 (n = 12) than in group 1 (n = 5) returned to sports at the same level as before the injury (P < 0.05). Patients from group 2 who returned to sports at the same level did so 2 months earlier than those in group 1. Thus the addition of OKC quadriceps training after ACL reconstruction results in a significantly better improvement in quadriceps torque without reducing knee joint stability at 6 months and also leads to a significantly higher number of athletes returning to their previous activity earlier and at the same level as before injury.

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The rehabilitation of knee injuries involving the anterior cruciate ligament (ACL) is controversial. This paper describes strain in the normal and reconstructed ACL during a series of passive and active tests of knee flexion with and without varus, valgus, and axial rotation torques on the tibia. Strain in the human knee ACL was significantly different depending on whether the knee flexion angle was changed passively or via simulated quadriceps contraction. The knee joint capsule was found to be important for strain protection of the ACL. Quadriceps activity did not strain the normal or reconstructed ACL when the knee was flexed beyond 60 degrees, but significantly strained the tissue from 0 to 45 degrees of knee flexion. Immobilization may not protect the ACL if isometric quadriceps contractions are allowed to occur. Properly placed reconstructions exhibited strain behavior which closely followed the anteromedial band of the ACL.

These data suggest that antibodies directed against the gamma2 chain of laminin-5 can identify cervical lesions with invasive capacity and thus may be useful as a sensitive marker of early invasion.

SummaryTo study the effects of standardized mental stress (arithmetic and the Stroop color word test) on plasma coagulation and fibrinolysis, blood samples were obtained before, during, and after 20 minutes of mental stress from 10 healthy, non-smoking young males aged 22 to 30 years. Reactions were compared with those observed during physical exercise and infusion of adrenaline. Both von Willebrand factor antigen and factor VIII coagulant activity increased significantly in response to mental stress (95 ± 28 vs 123 + 56%; p <0.05 and 125 ±54 vs 217 ± 170%; p <0.05, respectively). There was also a significant increase of factor VII coagulant activity (86 ± 31 vs 108 + 51%; p <0.05). Furthermore, mental stress caused an activation of the fibrinolytic system with an elevation of tissue plasminogen activator activity and tissue plasminogen activator antigen (0.80 ± 0.48 vs 1.23 ± 0.96 IU/ml; p = 0.076 and 4.38 ± 1.87 vs 5.78 ± 2.58 IU/ml; p <0.01). Fibrinogen concentration increased during stress (1.95 ± 0.29 vs 2.11 ± 0.27 g/1; p <0.05). Similar but more pronounced responses were observed during exercise and adrenaline infusion. Parallel to the increases in coagulation and fibrinolytic factors there were significant increases in heart rate, and systolic and diastolic blood pressure. It is concluded that mental stress has significant effects on plasma coagulation and fibrinolysis, and that it could thus affect important risk factors for cardiovascular disease.

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Twenty-three patients with stress fractures of the femoral neck were followed up at an average of 6.5 years after the injury. There were 16 recreational athletes and seven elite athletes. Most injuries (N = 15) occurred during running. The diagnosis was confirmed within 3 to 104 weeks (mean, 14 weeks) after the initial onset of symptoms. Sixteen of the patients were treated with internal fixation, the remaining seven were treated conservatively. Seven patients (30%) developed complications requiring major surgery. Five of these patients had Type 3 fractures (displaced) and four had been treated with internal fixation initially. The remaining two patients had Type 1 fractures (endosteal or periosteal callus without an overt fracture line); one was treated operatively and the other conservatively. Three patients developed avascular necrosis and two were treated by hip replacement. The third patient was treated with arthrodesis. Three refractures and one pseudarthrosis were treated by osteotomy. At followup, all elite athletes stated that they had to end their career as a result of the injury. Results were rated by the ability of the athlete to return to sports. There were 9 bad or fair results, 13 good, and 1 excellent result. No difference in activity level or subjective rating was observed between the surgically and conservatively treated group either preinjury or postinjury. The most important factor influencing the complication rate seems to be the type of fracture. The high incidence of displaced fractures (Type 3) could speculatively be caused by undiagnosed tension side stress fractures. If so, the delay in correct diagnosis may be disastrous. However, we could only objectively observe this in one of our cases.

A new mechanism for continued sac expansion based on aneurysm sac hygroma is proposed. Measurement of attenuation may be of diagnostic value. It is further proposed that local hyperfibrinolysis/coagulation may promote rebleeding, liquefaction, and continued expansion analogous to the chronic subdural hematoma.