Urinary retention and the role of indwelling catheterization following total knee arthroplasty.

INTRODUCTION: We aimed to investigate the rate of urinary retention after knee arthroplasty, the various factors involved in predicting those at risk for retention and to assess the impact of retention and catheterization on joint sepsis. MATERIALS AND METHODS: A retrospective review was conducted of all available case notes of patients undergoing total knee arthroplasty in a consecutive 2-year period (2000-2002). Adequate data was available for 142 patients. RESULTS: 142 patients underwent total knee arthroplasty. 19 patients were catheterized preoperatively for monitoring urine output. 123 patients were not catheterized. Urinary retention occurred in 19.7% (28/142). The mean day of catheterization for retention was 0.66. The mean duration of catheterization in patients developing retention was 3.58 days and was 3 days in the patients catheterized pre- or perioperatively. Deep joint sepsis occurred in 2.1% (3/142)--only one had been catheterized and that was preoperatively. No case of infection had urinary retention or had a symptomatic urinary tract infection. The only factors predicting those at significant risk of retention following knee arthroplasty was a past medical history of urinary retention (p = 0.049) and postoperative morphine requirement (p = 0.035). No patients required urological surgical intervention at mean follow up of 1.97 years. CONCLUSIONS: This study supports the use of indwelling urinary catheterization for patients developing urinary retention after total knee arthroplasty.

Urinary retention and the role of indwelling catheterization following total knee arthroplasty

INTRODUCTION: We aimed to investigate the rate of urinary retention after knee arthroplasty, the various factors involved in predicting those at risk for retention and to assess the impact of retention and catheterization on joint sepsis. MATERIALS AND METHODS: A retrospective review was conducted of all available case notes of patients undergoing total knee arthroplasty in a consecutive 2-year period (2000-2002). Adequate data was available for 142 patients. RESULTS: 142 patients underwent total knee arthroplasty. 19 patients were catheterized preoperatively for monitoring urine output. 123 patients were not catheterized. Urinary retention occurred in 19.7 percent (28/142). The mean day of catheterization for retention was 0.66. The mean duration of catheterization in patients developing retention was 3.58 days and was 3 days in the patients catheterized pre - or perioperatively. Deep joint sepsis occurred in 2.1 percent (3/142) - only one had been catheterized and that was preoperatively. No case of infection had urinary retention or had a symptomatic urinary tract infection. The only factors predicting those at significant risk of retention following knee arthroplasty was a past medical history of urinary retention (p = 0.049) and postoperative morphine requirement (p = 0.035). No patients required urological surgical intervention at mean follow up of 1.97 years. CONCLUSIONS: This study supports the use of indwelling urinary catheterization for patients developing urinary retention after total knee arthroplasty.

Tethering of the platelet-derived growth factor beta receptor to G-protein-coupled receptors. A novel platform for integrative signaling by these receptor classes in mammalian cells.

Here we provide evidence to show that the platelet-derived growth factor beta receptor is tethered to endogenous G-protein-coupled receptor(s) in human embryonic kidney 293 cells. The tethered receptor complex provides a platform on which receptor tyrosine kinase and G-protein-coupled receptor signals can be integrated to produce more efficient stimulation of the p42/p44 mitogen-activated protein kinase pathway. This was based on several lines of evidence. First, we have shown that pertussis toxin (which uncouples G-protein-coupled receptors from inhibitory G-proteins) reduced the platelet-derived growth factor stimulation of p42/p44 mitogen-activated protein kinase. Second, transfection of cells with inhibitory G-protein alpha subunit increased the activation of p42/p44 mitogen-activated protein kinase by platelet-derived growth factor. Third, platelet-derived growth factor stimulated the tyrosine phosphorylation of the inhibitory G-protein alpha subunit, which was blocked by the platelet-derived growth factor kinase inhibitor, tyrphostin AG 1296. We have also shown that the platelet-derived growth factor beta receptor forms a tethered complex with Myc-tagged endothelial differentiation gene 1 (a G-protein-coupled receptor whose agonist is sphingosine 1-phosphate) in cells co-transfected with these receptors. This facilitates platelet-derived growth factor-stimulated tyrosine phosphorylation of the inhibitory G-protein alpha subunit and increases p42/p44 mitogen-activated protein kinase activation. In addition, we found that G-protein-coupled receptor kinase 2 and beta-arrestin I can associate with the platelet-derived growth factor beta receptor. These proteins play an important role in regulating endocytosis of G-protein-coupled receptor signal complexes, which is required for activation of p42/p44 mitogen-activated protein kinase. Thus, platelet-derived growth factor beta receptor signaling may be initiated by G-protein-coupled receptor kinase 2/beta-arrestin I that has been recruited to the platelet-derived growth factor beta receptor by its tethering to a G-protein-coupled receptor(s). These results provide a model that may account for the co-mitogenic effect of certain G-protein-coupled receptor agonists with platelet-derived growth factor on DNA synthesis.

Lessons to be learned: a case study approach: metastatic bronchogenic carcinoma presenting as a gluteal abscess.

It is well known that bronchogenic carcinoma frequently metastasises to the bony skeleton, but it is most unusual for it to present in the form of a musculoskeletal abscess. Presented here is the case report of a patient with what appeared initially to be a right sided gluteal abscess and which turned out to be the metastasis from a bronchogenic carcinoma. The Magnetic Resonance Image (MRI) scan carried out proved to be very helpful in arriving at a probable clinical diagnosis; however, it was histopathological studies of the abscess wall itself that ultimately gave the definitive diagnosis. We believe that this may represent one of the first documented cases in which on MRI scan has been used to confirm the presence of a gluteal abscess.

Dispensing surgical gloves onto the open surgical gown pack does not increase the bacterial contamination rate.

In implant surgery air and surface contamination have become important factors in post-operative wound infection. We established the rate of contamination of surgical gown packs and found that dropping gloves onto the open gown pack prior to scrubbing had no effect on it. Ninety-six contact plates were used for this study, which was carried out during clean orthopaedic operations in one operating room. The overall rate of contamination was 65%. Most of the contaminants were skin commensals. The rate of contamination was 67% when gloves were dropped onto the gown pack compared with 63% when opened and presented to the scrubbed and gowned theatre staff. However this difference was statistically not significant. The high rate of contamination was probably due to the gown packs having been left opened for too long. This delay arose because each gown pack had three gowns and would have been avoided if single gown packs had been used.

Displaced bucket handle tears of the medial meniscus masking anterior cruciate deficiency.

Traditionally, anterior cruciate ligament (ACL) injuries have been difficult to diagnose in the Casualty Department. Studies have shown that the anterior drawer test has a poor sensitivity both in acute and chronic ACL deficient knees [4, 6, 9]; thus, more emphasis has been placed on the pivot shift and Lachman tests [3]. We report four cases of proven ACL rupture where clinical examination revealed an absent pivot shift and a near normal Lachman test following a displaced bucket handle tear of the medial meniscus. This finding has been reproduced in cadaver studies, and we conclude that if the history strongly suggests an ACL injury and examination reveals a stable knee, then the dual pathology of medial meniscus tear and ACL rupture should be suspected.

Irreducible isolated dislocation of the radial head in a skeletally mature teenager. A case report.

Isolated dislocation of the radial head is an uncommon injury. This injury has been reported in children; in the skeletally mature it is extremely rare. An irreducible dislocation has been previously reported in a young child, but no case has to date been reported in an adult. The present case is reported to demonstrate this rare injury and to suggest a possible explanation for the cause of the irreducibility.