Effect of Vertical or Beveled Chondral Defect Creation on Rim Deformation and Contact.

OBJECTIVE: To determine biomechanical effects of knee cartilage defect perimeter morphology based on cartilage strain and opposing subchondral bone contact. DESIGN: Articular cartilage defects were created in 5 bovine femoral condyles: group 1, 45° inner bevel with 8-mm rim; group 2, vertical with 8-mm rim; and group 3, 45° outer bevel with 8-mm base. Samples were placed into a custom-machined micro-computed tomography tube and subjected to 800 N of axial loading. DICOM data were used to calculate cartilage thickness 4 and 6 mm from the center, distance between tibial cartilage surface and femoral subchondral bone, and contact width between tibial cartilage and subchondral bone. Strain 4 mm from the center and both absolute and change in distance (mm) to subchondral bone were compared between groups 1 and 2 using paired t tests. Strain at 6 mm and distance changed, loaded distance, and contact width (mm) were compared between groups using the Friedman test with post hoc analysis using Wilcoxon signed rank test. RESULTS: No significant differences in rim strain were noted between groups 1 and 2 at 4 mm ( P = 0.10) and between groups 1, 2, and 3 at 6 mm ( P = 0.247) from the defect center. The loaded distance was significantly different between groups 1 and 3 ( P = 0.013). No significant change in distance to the subchondral bone was found between groups ( P = 0.156). The difference in subchondral bone contact area approached but did not reach significance ( P = 0.074). CONCLUSION: When debriding focal articular cartilage defects, establishment of an inner bevel decreases tissue deformation and contact with opposing subchondral bone.

Meniscal allograft transplantation: preoperative assessment, surgical considerations, and clinical outcomes.

The purpose of this review is to characterize the preoperative assessment of meniscal allograft transplantation (MAT) candidates, to detail MAT surgical techniques, and to evaluate current clinical outcome data on MAT. The MAT candidate is typically less than 50 years old and has a history of knee injury, previous meniscus surgery, and persistent pain. Physical exam generally reveals knee pain with joint line tenderness with normal radiographs and magnetic resonance imaging demonstrating the postmeniscectomized state. There are several common surgical techniques used for transplantation, with fixation achieved through sutures, bony fixation, or a combination of the two. Concomitant procedures such as anterior cruciate ligament reconstruction, osteotomy, and other cartilage procedures are commonly performed. The available short- and long-term studies of clinical outcomes of MAT are variable and difficult to effectively compare due to heterogeneity of the study population and available treatment techniques. In addition, there are no published randomized controlled trials. However, recent reviews and cohort studies of clinical outcomes following MAT have shown that whether performed in isolation or performed with concomitant articular cartilage, realignment, or soft tissue reconstruction procedures MAT outcomes have been acceptable with the majority of studies reporting improved clinical outcomes regardless of the scoring system employed. MAT has proven to be a safe and effective technique in reducing knee pain and improving function in the symptomatic meniscal deficient knee. Evaluation of long-term clinical outcomes is necessary as is evaluation of meniscal replacement alternatives.

Considerations for the use of platelet-rich plasma in orthopedics.

The use of platelet-rich plasma (PRP) is expanding to numerous medical fields, including orthopedic surgery and sports medicine. The popularity of this new treatment option has prompted a rapid increase in research endeavors; however, the differences in application technique and the composition of PRP have made it difficult to compare results or make any firm conclusions regarding efficacy. The purpose of this article is twofold. First, to recommend details that should be provided in basic science and clinical PRP studies to allow meaningful comparisons between studies which may lead to a better understanding of efficacy. Second, to provide an understanding of the different PRP preparations and their clinical relevance. There are biochemical rationales for the use of PRP because it addresses several aspects of the healing process, including cell proliferation and tissue matrix regeneration, inflammation, nociception, infection, and hemostasis, all of which will be addressed. Given the current understanding of the importance the composition of PRP plays in tissue regeneration, it is likely that our future understanding of PRP will dictate 'customizing' the PRP preparation to the specific pathology of interest. The potential complications following PRP use are minor, and thus it appears to be a safe treatment option with a variety of potentially beneficial effects to injured musculoskeletal tissues.