Infection should be in the differentia for any painful total hip or knee. A thorough history and physical, complete set of radiographs and appropriate labs including C-reactive protein and erythrocyte sedimentation rate are essential in the initial evaluation. Ancillary tests such as aspiration and nuclear imaging may be helpful in unclear cases or when labs are concerning for infection. It is essential that all antibiotics are discontinued several weeks prior to gram stain and culture, if possible, to reduce the number of false negative test results. Classifying infection into acute versus late infection aids in the treatment plan. For acute infections presenting within 2 to 4 weeks of symptom onset, irrigation and debridement with polyethylene liner exchange and retention of components may be possible. When attempting component retention, thorough debridement and rapid treatment of the infection prior to the accumulation of any biofilm is paramount for a successful outcome. Other important prognostic factors to consider include the virulence of the microorganism as well as the immune status of the host. Despite expeditious management, irrigation and debridement of acute total hip and knee infections frequently leads to recurrent infection. Thus, patients should be counseled accordingly. Further management may be needed following an initial attempt at component retention. These options include resection arthroplasty with or without re-implantation, long term antibiotic suppressive therapy, arthrodesis and even above the knee amputation in rare circumstances. For chronic infections, a successful outcome depends on several factors including the baseline health status of the patient, implant removal with a thorough debridement followed by culture specific antibiotic treatment. Furthermore, methods of monitoring for persistent infection include following laboratory values such as the C-reactive protein, erythrocyte sedimentation rate, and cultures from joint aspirations. Whether to perform a direct exchange versus a delayed revision arthroplasty for chronic total hip and knee infections can be debated. Several published series have reported successful outcomes with single stage procedures when patients are carefully selected. However, the majority of chronic infections in the United States are treated with two stage resection, since this method has consistently provided the highest cure rates, with many current studies demonstrating >90% success.

Cartilage injuries are frequently recognized as a source of significant morbidity and pain in patients with previous knee injuries. The majority of patients who undergo routine knee arthroscopy have evidence of a chondral defect. These injuries represent a continuum of pathology from small, asymptomatic lesions to large, disabling defects affecting a major portion of one or more compartments within the knee joint. In comparison to patients with osteoarthritis, individuals with isolated chondral surface damage are often younger, significantly more active, and usually less willing to accept limitations in activities that require higher impact. At the present time, a variety of surgical procedures exist, each with their unique indications. This heterogeneity of treatment options frequently leads to uncertainty regarding which techniques, if any, are most appropriate for patients. The purpose of this review is to describe the workup and discuss the management techniques for cartilage injuries within the adult knee.

Total knee arthroplasty (TKA) performed in knees with mild or moderate intraarticular deformity often can be resolved with careful ligament balancing and bone resection. However, extra-articular deformity may require an osteotomy to safely create rectangular flexion and extension gap balance. In these challenging situations, restoring the mechanical axis through intra-articular bone resection and soft tissue releases alone can lead to excessive bone loss and ligament instability. We report a case of TKA with combined femoral and tibial osteotomies in a post-polio patient with extra-articular deformities. Although a few small case studies have been previously published in the literature, specific details regarding this procedure are lacking. Our objective is to provide a detailed surgical technique and to review the indications for extra-articular osteotomies performed during TKA. [J Knee Surg. 2009;22:21-26.]

High tibial osteotomy can provide 10 to 15 years of consistent pain relief and improved function for most patients with unicompartmental knee arthritis. However, some studies have reported less predictable results, with deteriorating survivorship after 10 years of follow-up. Therefore, it is paramount to carefully select patients and to understand that technical errors during surgery often lead to poor outcomes. It is well established that obese patients, as well as undercorrected osteotomies, often lead to early failure, with rapid degeneration of the arthritic compartment. Although many surgical techniques describing high tibial osteotomies have been previously published, most techniques share similar surgical principles. What differentiates our technique from others is the mode of harvesting local autograft bone to fill our osteotomy site. For several years, a specialized harvester has been used to obtain distal femoral cancellous bone. This technique is simple, efficient, reproducible, and safe. This article reviews the novel technique for opening wedge high tibial osteotomies.[J Knee Surg. 2008;21:80-84.]

Corynebacterium pseudodiphtheriticum is a normal inhabitant of the upper respiratory tract and is rarely thought of as a true pathogen. Although this microorganism has been associated with respiratory complications, a few case reports have demonstrated its ability to cause orthopedic infections. A recent review of the literature was performed regarding this specific bacteria and its association with bone and joint infection. To the author's knowledge, the current case is the first reported case of chronic osteomyelitis from Corynebacterium pseudodiphtheriticum after arthroscopic knee surgery. Isolation of this bacterial species on routine microbial cultures has been proven to be challenging in prior studies. In the current case, difficulty isolating this bacterial species on routine cultures led to a significant delay in diagnosis, which ultimately resulted in end-stage joint destruction. Treatment of the infection was accomplished using a 2-stage total knee arthroplasty technique, with the initial placement of an articulated, antibiotic-loaded spacer followed by a subsequent conversion to total knee arthroplasty. This case serves as a useful reminder that clinically subtle infections can occur after minor orthopedic surgery. Surgeons must remain vigilant to render a timely diagnosis and avoid severe sequelae that can result from an undetected pathogen after arthroscopic surgery.