Techniques of exposure for the stiff total knee

Primary and revision total knee arthroplasty have become common orthopaedic procedures. The operating surgeon, at times, may be faced with a difficult surgical case due to soft tissue contractures or bone deformities. A review of multiple surgical techniques using soft tissue releases and osteotomies are presented including their potential complications. Although these techniques are aimed at the atypical operative case, the operating surgeon may utilize them for ‘routine’ exposures as well. Importance is focused on the functional integrity of the knee extensor mechanism.     

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.      

Analgesic effects of botulinum toxin A: a randomized, placebo-controlled clinical trial

Postoperative pain in children with spastic cerebral palsy (CP) is often attributed to muscle spasm and is difficult to manage using opiates and benzodiazepines. Adductor-release surgery to treat or prevent hip dislocation in children with spastic CP is frequently performed and is often accompanied by severe postoperative pain and spasm. A double-blinded, randomized, placebo-controlled clinical trial of 16 patients (mean age 4.7 years) with a mainly spastic type of CP (either diplegic or quadriplegic in distribution) was used to test the hypothesis that a significant proportion of postoperative pain is secondary to muscle spasm and, therefore, might be reduced by a preoperative chemodenervation of the target surgical muscle by intramuscular injection of botulinum toxin A (BTX/A). Compared with the placebo, BTX/A was found to be associated with a reduction in mean pain scores of 74% (P<0.003), a reduction in mean analgesic requirements of approximately 50% (P<0.005), and a reduction in mean length of hospital admission of 33% (P<0.003). It was concluded that an important component of postoperative pain in the patient population is due to muscle spasm and this can be managed effectively by preoperative injection with BTX/A. These findings may have implications for the management of pain secondary to muscle spasm in other clinical settings.     

Changing Methods of Imaging the Common Bile Duct in the Laparoscopic Cholecystectomy Era in Western Australia: Implications for Surgical Practice

OBJECTIVE: To assess changes in the use of endoscopic retrograde cholangiopancreatography (ERCP), intraoperative cholangiography (IOC), and surgical exploration of the common bile duct (CBD) associated with the introduction of laparoscopic cholecystectomy (LC). SUMMARY BACKGROUND DATA: The optimal strategy for dealing with potential stones of the CBD during LC remains controversial. METHODS: The authors conducted a population-based study of all cases of cholecystectomy (20,084) in Western Australia in the periods before, during, and after the introduction of LC (1988-1994). Index admissions were linked to previous or subsequent admissions for ERCP. Factors associated with ERCP were analyzed by multivariate regression models. RESULTS: Between 1988 and 1994, admissions for ERCP almost doubled, whereas the use of IOC decreased from 71% to 51%. Different trends were found for open and laparoscopic procedures. Exploration of the CBD declined because of the infrequent use of this procedure in LC. Preoperative ERCP was significantly more common in older patients and men; the reverse was found for IOC. There was an adjusted 3.5-fold increase in preoperative ERCP both during and after the introduction of LC. The adjusted odds ratios for IOC were 0.48 and 0.52 for these periods. CONCLUSIONS: The introduction of LC was associated with increasing reliance on ERCP to image the CBD and a decrease in the use of IOC. These changes were observed in both LC and open cholecystectomy. They suggest that the use of ERCP before cholecystectomy has partly replaced IOC for visualization of the CBD for suspected stones. Although more than 40% of patients undergoing LC had IOC, surgeons appear to be reluctant to perform surgical exploration of the CBD when stones are present. Savings in terms of both complications and cost can be expected if preoperative ERCPs performed for suspicion of uncomplicated CBD stones are replaced by IOC.     

Ovine forestomach matrix biomaterial is a broad spectrum inhibitor of matrix metalloproteinases and neutrophil elastase

Proteases play a critical role in the ordered remodelling of extracellular matrix (ECM) components during wound healing and tissue regeneration. However, the usually ordered proteolysis is compromised in chronic wounds due to over‐expression and high concentrations of matrix metalloproteinase's (MMPs) and neutrophil elastase (NE). Ovine forestomach matrix (OFM) is a decellularised extracellular matrix‐based biomaterial developed for tissue regeneration applications, including the treatment of chronic wounds, and is a heterogeneous mixture of ECM proteins and proteoglycans that retains the native structural and functional characteristics of tissue ECM. Given the diverse molecular species present in OFM, we hypothesised that OFM may contain components or fragments that inhibit MMP and NE activity. An extract of OFM was shown to be a potent inhibitor of a range of tissue MMPs (IC₅₀s = 23 ± 5 to 115 ± 14 µg/ml) and NE (IC₅₀ = 157 ± 37 µg/ml), and was more potent than extracts prepared from a known protease modulating wound dressing. The broad spectrum activity of OFM against different classes of MMPs (i.e. collagenases, gelatinases and stromelysins) may provide a clinical advantage by more effectively addressing the protease imbalance seen in chronic wounds.