Panagiotis Koulouvaris

Epidemiology of Anterior Cruciate Ligament Reconstruction: Trends, Readmissions, and Subsequent Knee Surgery

BACKGROUND Anterior cruciate ligament reconstruction is widely accepted as the treatment of choice for individuals with functional instability due to anterior cruciate deficiency. There remains little information on the epidemiology of anterior cruciate ligament reconstruction with regard to adverse outcomes such as hospital readmission and subsequent knee surgery. We sought to identify the frequency of anterior cruciate ligament reconstruction, the rates of subsequent operations and readmissions, and potential predictors of these outcomes. METHODS The Statewide Planning and Research Cooperative System (SPARCS) database, a census of all hospital admissions and ambulatory surgery in New York State, was used to identify anterior cruciate ligament reconstructions performed between 1997 and 2006. Patients with concomitant pathological conditions of the knee were included. The patients were tracked for hospital readmission within ninety days after the surgery and for subsequent surgery on either knee within one year. The risks of these outcomes were modeled with use of age, sex, comorbidity, hospital and surgeon volume, and inpatient or outpatient surgery as potential risk factors. RESULTS We identified 70,547 anterior cruciate ligament reconstructions, with an increase from 6178 in 1997 to 7507 in 2006. Readmission within ninety days after the surgery was infrequent (a 2.3% rate), but subsequent surgery on either knee within one year was much more common (a 6.5% rate). Patients were at increased risk for readmission within ninety days if they were over forty years of age, sicker (e.g., had a preexisting comorbidity), male, and operated on by a lower-volume surgeon. Predictors of subsequent knee surgery included being female, having concomitant knee surgery, and being operated on by a lower-volume surgeon. Predictors of a subsequent anterior cruciate ligament reconstruction included an age of less than forty years, concomitant meniscectomy or other knee surgery, and surgery in a lower-volume hospital. CONCLUSIONS The rate of anterior cruciate ligament reconstruction has increased in frequency. Also, while anterior cruciate ligament reconstruction appears to be a safe procedure, the risk of a subsequent operation on either knee is increased among younger patients and those treated by a lower-volume surgeon or at a lower-volume hospital.

The Central Role of Wear Debris in Periprosthetic Osteolysis

Periprosthetic osteolysis remains the leading complication of total hip arthroplasty, often resulting in aseptic loosening of the implant, and a requirement for revision surgery. Wear-generated particular debris is the main cause of initiating this destructive process. The purpose of this article is to review recent advances in our understanding of how wear debris causes osteolysis, and emergent strategies for the avoidance and treatment of this disease. The most important cellular target for wear debris is the macrophage, which responds to particle challenge in two distinct ways, both of which contribute to increased bone resorption. First, it is well known that wear debris activates proinflammatory signaling, which leads to increased osteoclast recruitment and activation. More recently, it has been established that wear also inhibits the protective actions of antiosteoclastogenic cytokines such as interferon gamma, thus promoting differentiation of macrophages to bone-resorbing osteoclasts. Osteoblasts, fibroblasts, and possibly lymphocytes may also be involved in responses to wear. At a molecular level, wear particles activate MAP kinase cascades, NFκB and other transcription factors, and induce expression of suppressors of cytokine signaling. Strategies to reduce osteolysis by choosing bearing surface materials with reduced wear properties (such as metal-on-metal) should be balanced by awareness that reducing particle size may increase biological activity. Finally, although therapeutic agents against proinflammatory mediators [such as tumor necrosis factor (TNF)] and osteoclasts (bisphosphonates and molecules blocking RANKL signaling) have shown promise in animal models, no approved treatments are yet available to osteolysis patients. Considerable efforts are underway to develop such therapies, and to identify novel targets for therapeutic intervention.

Relationship Between Perioperative Urinary Tract Infection and Deep Infection After Joint Arthroplasty

Surgical wound infection is a serious and potentially catastrophic complication after joint arthroplasty. Urinary tract infection is a common infection that creates a potential reservoir of resistant pathogens and increases patient morbidity. We asked whether treated preoperative and postoperative urinary tract infections are risk factors for deep joint infection. We examined the medical records of 19,735 patients. The minimum had joint infections develop. Of these, three had preoperative and four had postoperative urinary tract infections. The majority of bacteria were not enteric. The bacteria in the two types of infections were not identical. Control subjects were randomly selected from a list of patients matched with patients having infections. Of these, eight had preoperative and one had postoperative urinary tract infections. We found no association between the preoperative urinary tract infection (odds ratio, 0.341; 95% confidence interval, 0.086–1.357) or postoperative urinary tract infection (odds ratio, 4.222; 95% confidence interval, 0.457–38.9) and wound infection. Only one of the 58 patients with wound infections had a urinary tract infection with the same bacteria in both infections. Given the infection rate was very low (0.29%), the power of the study was only 25%. Although limited, the data suggest patients with urinary tract infections had no more likelihood of postoperative infection. We believe treated urinary tract infection should not be a reason to delay or postpone surgery.Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Distal Femoral Shortening in Total Hip Arthroplasty for Complex Primary Hip Reconstruction. A New Surgical Technique

Successful total hip arthroplasty (THA) in congenital dislocated hips demands anatomical reduction in the normal center of rotation without overstretching the sciatic nerve and without excessive compression or abnormal forces across the joint. Proximal femoral and subtrochanteric shortening osteotomy has been described for THA for the treatment of dislocated hips. However, these osteotomies are demanding, associated with deformation of femoral canal and nonunion, and may increase the femoral stem stress. This study reports excellent results in 24 patients with a new surgical technique that combines THA with a distal femoral shortening in severely deformed hips using customized components.

Incidence of Heterotopic Ossification in Patients Receiving Radiation Therapy following Total Hip Arthroplasty

Heterotopic ossification (HO) is a frequent complication of hip surgery. In this study the incidence of HO is analyzed in high risk patients who received radiation therapy (RT) after total hip replacement (THA) with regular and miniposterolateral hip approach. Two hundred and thirty five high risk patients received a single dose of 700 rad after THA. The incidence of HO was 15.7%. The incidence of HO in the high risk subgroup with the miniincision was lower (5.7%) but not significantly different (). Hypertrophic osteoarthritis was demonstrated to be the consistent predisposing factor for HO formation ().