The role of the scapula.

The scapular musculature is often neglected in designing a rehabilitation protocol for the shoulder. Weakness of the scapular stabilizers and resultant altered biomechanics could result in: 1) abnormal stresses to the anterior capsular structures of the shoulder, 2) increased possibility of rotator cuff compression, and 3) decreased performance. This article presents known facts about the biomechanics of the scapula and surrounding muscles and suggests methods for evaluation of scapular muscle weakness. Exercise techniques to maximally strengthen the scapular musculature are also described. As our ability to document strength of these muscles improves, we will be able to determine the effect of scapular strengthening on improving symptoms related to impingement and instability. Scapular strengthening exercises are usually nonstressful to the rotator cuff and are easily implemented into a rehabilitation program for the shoulder.

Simultaneous high tibial osteotomy and ACL reconstruction for combined genu varum and symptomatic ACL tear.

This article reviews the subjective, objective, functional, and radiographic results of five patients with symptomatic anterior cruciate instability, genu varum, and varus rotational instability treated by sequential high tibial osteotomy and anterior cruciate ligament reconstruction at one operative procedure. The average patient age was 27 years (range: 21 to 35), and the average follow up was 2.5 years (range: 2 to 3). All patients had symptomatic instability with anterior tibia subluxation, which was documented by KT-1000 testing. All patients also had a varus alignment clinically and radiographically with medial compartment pain. Postoperatively, the medial compartment pain was improved, and instability episodes were eliminated. Side to side differences (KT-1000--manual maximum) were reduced to 3.1 mm. There were no complications. The instability episodes were eliminated, and functional levels were improved in all patients. We concluded that, for this select group of patients, simultaneous extremity realignment and ligament stabilization will effectively manage both conditions without compromising the results of either procedure.

In vivo measurement of anterior tibial translation using continuous passive motion devices.

Early motion protocols following anterior cruciate reconstruction often use continuous passive motion devices. There is concern that these devices may induce undesired anterior translation of the tibia and resulting graft stretching or rupture. This study measured the amount of anterior tibial translation that occurred during one cycle in 10 different brands of continuous passive motion devices. Five patients with ACL deficient knees participated in this study. Anterior translation was recorded by using an electrogoniometer with four degrees of freedom (Knee Signature System). Anterior translation measurements were also recorded for a 20 pound Lachman test in these same five patients using the Knee Signature System. Two of the devices showed anterior translation measurements that approached the recorded 20 pound Lachman values. These two devices had a high calf bar for the primary support of the leg. The results indicate that, when using a continuous passive motion device for early postoperative management of the reconstructed ACL in a patient, use of a calf-supporting type of continuous passive motion could induce an undesired strain of the healing graft.

Comparison of anterior laxity measurements in anterior cruciate deficient knees with two instrumented testing devices.

We measured anterior tibial displacements in 21 anterior cruciate ligament deficient patients using two instrumented testing devices, the KT-1000 and the KSS. A comparison of values obtained from testing was done using statistical analysis. The two tests common to both devices were the 20 lb pull and the manual maximum. The involved normal (I-N) values showed that there was no significant difference between the two devices for both the manual maximum and the 20 lb force level. There was also no significant difference between devices for the manual maximum absolute values. The significant difference between the absolute values for the 20 lb force level is probably due to the different testing techniques for both devices. When testing with the KSS, the patella remains free; testing with the KT-1000 requires that the examiner maintain pressure to hold the patella down. The manual maximum absolute values showed no significant difference because the testing techniques for both devices were identical. Comparable data for both devices are the I-N values for the 20 lb and manual maximum values.

Toxicity and immunosuppressive activity of binary combinations of 2'-deoxycoformycin and 2'-deoxyadenosine.

Treatment of mice with 2'-deoxycoformycin (dCf) for 5 days produced inhibition of spleen and lymph node adenosine deaminase (E. C. 3.5.4.4) activity but no hematologic toxicity or weight loss. A 64-fold elevation of erythrocyte dATP was observed. However, if mice were injected with 2'-deoxyadenosine (AdR) in combination with dCf, weight loss, hematologic toxicity, and liver cell necrosis occurred. These mice had a severe blood coagulation defect and a 73-fold elevation of plasma alanine transaminase activity, plasma prealbumin became undetectable, and erythrocyte dATP levels were elevated 1500-fold. Death during treatment appeared to be from acute liver failure since bone marrow toxicity was only detected following termination of treatment. These effects were not seen in mice receiving adenosine in combination with dCf. dCf, either alone or in combination with AdR, inhibited the contact sensitization to oxazalone in mice. The inhibition was associated with signs of systemic toxicity which were more pronounced in the combination-treated groups. If dATP is the toxic metabolic accumulated in the malignant cells of patients treated with dCf, we propose that AdR supplementation of treatment should be considered with extreme caution since severe damage to normal tissues might result.

The clinical pharmacology of the adenosine deaminase inhibitor 2'-deoxycoformycin.

2'-deoxycoformycin (2'-dCF; Pentostatin), a stoichiometric inhibitor of mammalian adenosine deaminase (ado deaminase), exhibits immunosuppressive and antilymphocytic activity in animal test systems. A clinical pharmacology/phase I study of 2'-dCF administered as a single agent has been completed (18 patients). Dose levels ranged from 0.1 mg/kg X 1 to 0.25 mg/kg/day X 5; ado deaminase and 2'-dCF were measured spectrophotometrically. Plasma decay curves were bi-exponential (alpha and beta t 1/2 values about 1 and 10 h respectively). Recovery of unchanged 2'-dCF from urine (48 h) was 32%--48% of the administered drug. Major toxic manifestations were lymphocytopenia (all patients) and urate nephropathy (1 patient, with subsequent patients in the series receiving allopurinol, 300 mg/day). Three partial responses were seen in seven patients with acute lymphocytic leukaemia receiving 0.25 mg 2'-dCF/kg/day X 5.