Isokinetic and functional shoulder outcomes after arthroscopic capsulolabral stabilization.

INTRODUCTION: Shoulder stability is secured by dynamic and static stabilizers. Rotator cuff is responsible for dynamic stabilization. In cases of shoulder instability their activity is disturbed. Capsulolabral repair restores mainly static stabilization. This surgery treatment technique of shoulder instability was first described by Bankart in 1923. His idea, with further modifications, is commonly used up to this day. Evaluation of muscle shoulder recovery after stabilization should be one of the important criteria to allow patient to return to sport and work. However, not much isokinetic assessment after capsulolabral repair was described. The aim of this study were the following: the comparative assessment of the shoulder rotatory strength in patients following arthroscopic capsulolabral repair of unilateral anterior traumatic instability and clinical assessment with comparison of pre and post-operative results. MATERIAL AND METHODS: Forty-five patients, 14 women and 31 men, with an average follow-up of 4.4 years were tested bilaterally for internal and external rotation strength at four angular velocities. ASES and UCLA tests were collected before and after surgery. RESULTS: The values of peak moment and muscle power parameters were slightly lower for an operated shoulder in comparison to a healthy shoulder for the external rotation. Total work parameter in external rotation was significantly lower for the operated shoulder in comparison to the non-operated side. The internal/external muscle group balance was lower for the operated shoulder in comparison to reference values in the women group. Furthermore, both ASES and UCLA scores were significantly higher after operation. CONCLUSIONS: After arthroscopic capsulolabral shoulder stabilization, slight differences in isokinetic evaluation, especially in external shoulder rotation, occur. It affects rotators muscle balance. In functional evaluation significant improvement in shoulder function occurs.

The outcome of open elbow arthrolysis: comparison of four different approaches based on one hundred cases.

PURPOSE: The aim of this study was to evaluate the results of elbow arthrolysis according to the surgical approach, durability after arthrolysis and the severity of contracture. METHODS: The study includes a cohort of 100 consecutive patients treated in our institution between 1986 and 2008. The indication for surgery was loss of mobility. This was the result of fractures, dislocation, simultaneous fracture/dislocation or other non-traumatic causes. All patients underwent open elbow release via one of four approaches (42 lateral, 44 medial, six combined medial-lateral and eight posterior). They were clinically evaluated at a minimum of 24 months after arthrolysis. RESULTS: The average ranges of elbow extension, flexion and arc of motion had increased significantly at the follow up, respectively, by 20°, 16° and 36°. No significant difference was found with regard to surgical approach. However, we noticed significant deterioration of intra-operative average extension and arc of motion (AOM) over the follow up period, respectively, by 13° and 14°. The number of patients with AOM of 100° or more increased from three patients preoperatively to 28 postoperatively. CONCLUSIONS: Open elbow arthrolysis is a successful method of treatment of elbow contracture. Results are durable, but there is some postoperative deterioration of extension gained during surgery. We may anticipate that at the final stage we shall obtain an average of 86% of intra-operative arc of motion. Patients with the most severe contractures have the best gains.

PNUTS (phosphatase nuclear targeting subunit) inhibits retinoblastoma-directed PP1 activity.

Protein phosphatase type 1 catalytic subunit (PP1c) is a serine/threonine phosphatase involved in the dephosphorylation of many proteins in eukaryotic cells. It associates with several known targeting or regulatory subunits that directly regulate PP1c activity toward specific substrates. The recently identified Phosphatase Nuclear Targeting Subunit (PNUTS) binds to PP1c and inhibits PP1 activity toward phosphorylase a. One of the substrates of PP1c has been shown to be the cell cycle regulatory protein, Retinoblastoma (pRb). In this study, we show that PNUTS dissociates from PP1c under mildly hypoxic cell growth conditions that lead to an increase of PP1c activity toward pRb. We developed an assay that measures pRb-directed PP1c activity and show that a GST-PNUTS fusion protein inhibits phosphatase activity toward pRb when using PP1c from cell lysates, GST-PP1c, or purified PP1c. These studies suggest that PNUTS is involved in the regulation of PP1c activity toward pRb.

Hypoxia stimulates p16 expression and association with cdk4.

Exposure of CV-1P cells to hypoxic conditions causes cell proliferation inhibition concomitant with the accumulation of pRb in the hypophosphorylated, growth suppressive form. This is in part due to inhibition of pRb-directed cdk4 and cdk2 activity. In this study we attempted to elucidate the mechanism by which cdk4 is inactivated under hypoxic conditions. After 18 h of hypoxia, CV-1P cells are inhibited from progressing from G(1) phase into the S phase of the cell cycle. This occurs in conjunction with dephosphorylation of serine-795, which is a putative substrate of cdk4. The amounts of cdk4, cdk6, and the D type cyclins are not affected by 18 h of hypoxia. The levels of cdki p16, p18, p19, and p57 under aerobic or hypoxic conditions were analyzed and although the levels of most cdki are unaffected by hypoxic conditions, the level of p16 increases significantly by 18 h of hypoxia. The mechanism by which cdk4 activity is inhibited under hypoxic conditions may be mediated through p16 association with cdk4. Immunoprecipitation analysis shows that p16 binds to cdk4 under hypoxic conditions but does not in cells maintained under aerobic conditions. Thus p16 may be involved in hypoxia-induced growth inhibition.