Bariatric Surgery Prior to Total Joint Arthroplasty, Does it Decrease the Risk of Obesity Related Perioperative Complications?

PURPOSE OF REVIEW: The purpose of this review paper is to provide an overview of the relationship between obesity, osteoarthritis, arthroplasty outcomes, and the potential use of bariatric surgery to improve these outcomes. RECENT FINDINGS: Unfortunately, the findings in the currently available literature evaluating the role of bariatric surgery prior to arthroplasty surgery largely rely on retrospective data and their results are somewhat conflicting. Future prospective studies are needed to further evaluate whether or not bariatric surgery prior to arthroplasty surgery may be of benefit for patients. Additional research is needed to identify other methods to minimize complications that obese patients are particularly prone to developing following arthroplasty surgery.

Nerve injury after primary total knee arthroplasty.

There is controversy about the incidence of and predisposing factors to the development of peripheral nerve palsy after total knee arthroplasty (TKA). In this study, 19 patients with a documented neurologic complication were identified after a retrospective review of 1,476 primary TKAs performed between January 1970 and December 1998 at the New York Presbyterian Hospital at Columbia University, for an overall incidence of 1.3%. Contrary to previously published data, valgus deformity, flexion contracture, the use of postoperative epidural anesthesia, the prolonged use of pneumatic tourniquets, and preexisting neuropathy were not associated with the development of peripheral neuropathy after TKA based on our data. A larger percentage of rheumatoid knees experienced a neurologic injury than was expected, however. No other significant risk factors for peripheral neuropathy after TKA were identified based on data from our patients. Immediately after discovery of the nerve palsy, conservative treatment was employed for each of our patients. All patients showed at least a partial recovery at the end of follow-up, with most experiencing a complete recovery from symptoms.

Effect of increasing temperature on the properties of four bone cements.

This investigation uses a laboratory model to evaluate the effects of a heated femoral stem on the biomechanical properties of four common acrylic bone cements. American Society for Testing Materials dog bone shaped acrylic cement specimens made at four test temperatures, 0 degree C, 23 degrees C, 37 degrees C and 50 degrees C, were tested for modulus, ultimate tensile strength, fracture toughness, and percent porosity. Fatigue strength was tested in Simplex P at 23 degrees C and 37 degrees C. The data allow direct comparison among four cement brands at each of the four temperature conditions. No adverse changes of the mechanical properties were found for any cement at any temperature. Modulus, fracture toughness, and fatigue strength were unaffected by increased temperature. Ultimate tensile strength increased in Simplex P and Zimmer Osteobond but was unaffected for Zimmer Regular and Palacos R cements. Percent porosity was related to temperature changes inversely in all brands studied, except for Palacos R which consistently had low porosity, unaffected by temperature variation. Fatigue strength of Simplex P was unaffected by heating to 37 degrees C. Based on this laboratory model, heating of the femoral stem could save time without sacrificing mechanical properties of acrylic bone cement.