Anatomical and Radiographic Characterization of the Lateral Patellofemoral Ligament of the Knee.

The purpose of the current study was to describe the femoral and patellar insertions of the lateral patellofemoral ligament (LPFL) and to determine their location relative to known anatomic and radiographic landmarks. In this descriptive laboratory study, 10 cadaveric knees were dissected, and the patellar and femoral insertions of the LPFL were identified. Each specimen was examined radiographically. The average center of the femoral insertion of the LPFL was calculated in reference to radiographic landmarks.

Fibrocartilaginous metaplasia and neovascularization of the anterior cruciate ligament in patients with osteoarthritis.

INTRODUCTION: The anterior cruciate ligament (ACL) prevents the anterior translocation and medial rotation of the tibia against the femur. It is typically composed of dense regular connective tissue (DRCT), small amount of loose connective tissue, little vasculature, and few nerve endings. The objective of the current study was to evaluate the details of histological changes in ACLs of patients with clinically diagnosed osteoarthritis (OA). MATERIALS AND METHODS: The ACLs of six patients undergoing total knee replacement because of OA (OA group) were compared with 16 normal ACLs from cadavers (control). The ACLs were analyzed for tissue composition and number of blood vessels across the full length and thickness of the ligament. Percentages for areas of DRCT, fibrocartilage, degenerative tissue, and vasculature were calculated. Tissue composition and relative number of blood vessels were compared between groups. RESULTS: The proportion of DRCT to non-DRCT was significantly smaller in the OA group than the control group (p < .001); non-DRCT included degenerative connective tissue and fibrocartilage. The number of blood vessels to area was greater in the OA group than the control group (p = .002). Six of control (37.5%) and five of OA ACLs (83%) showed areas of calcification. CONCLUSIONS: These results indicate that inflammatory processes contributing to OA in the knee cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, calcification, and formation of fibrocartilage-like tissue inside the ligament. These changes make ligament-retaining total knee arthroplasty a less beneficial option for knee repair.

The feasibility of randomized controlled trials for early arthritis therapies (Earth) involving acute anterior cruciate ligament tear cohorts.

Osteoarthritis (OA) is a leading cause of disability for which disease-modifying treatments are lacking. Anterior cruciate ligament (ACL) tear provides opportunities to study potential interventions from the initiation of heightened OA risk at the time of injury. This institutional review board (IRB)-approved prospective cross-sectional study (level of evidence: 2) was performed to test the hypothesis that adequate sample sizes of ACL-injured subjects to support randomized controlled trials (RCT) of early intervention strategies can be achieved. A total of 307 ACL-injured patients were entered into the database from 3-month collection periods at 7 clinical sites, with 65 subjects aged 18 to 30 years passing the inclusion/exclusion criteria. From sites that were IRB approved to ask, 89 of 96 (93%) subjects were willing to participate in an RCT. Extrapolating the 3-month data to a 1-year recruitment period would potentially yield 242 subjects aged 18 to 30 years willing to undergo randomization. This study shows that adequate sample sizes to perform RCT of early intervention strategies in ACL-injured cohorts comprising healthy young adults ages 18 to and 30 without prior joint injuries can be achieved within 1 to 2 years through recruitment at 5 to 7 orthopaedic sports medicine practices. Continued development of ACL-tear cohorts will provide the clinical base to critically evaluate new diagnostic and therapeutic strategies that can help transform clinical care of OA from palliation to prevention.

Extra-articular synovial fluid extravasation following operative fixation of an osteochondral fracture of the patella.

Osteochondral fracture of the patella following a lateral patellar dislocation can be treated with operative and nonoperative techniques that are dictated by the clinical presentation. In the presence of large fragments following acute fractures, arthroscopic retrieval and fixation are advocated, whereas smaller displaced fragments may be removed and discarded as loose bodies. Several methods of fixation exist for osteochondral fractures of the patella, including the use of cannulated and noncannulated screws.This article describes a case of an elite competitive swimmer who sustained a lateral patellar dislocation with a large osteochondral fracture of the patella that was treated with open reduction and fixation using absorbable cannulated screws in an inside-out fashion. In the early postoperative period, the patient developed a symptomatic synovial fluid fistula through a cannulated screw to the prepatellar space. The diagnosis of this condition was made clinically and confirmed with noncontrast magnetic resonance imaging 6 weeks postoperatively. The symptoms of pain, skin erythema, and swelling were self-limited and eventually resolved with observation, allowing the athlete to return to his previous activity level. Magnetic resonance imaging 3 years postoperatively showed the complete resolution of the fluid extravasation. Extra-articular synovial fluid extravasation is as a rare complication following routine knee arthroscopy, accounting for 3.2% of the complications. This article describes a rare, self-limited complication following open fixation of an osteochondral fracture of the patella.

Effects of dexamethasone on the functional properties of cartilage explants during long-term culture.

BACKGROUND: Intact articular cartilage tissue is used clinically in the form of osteochondral allografts and experimentally as explants in modeling the physiologic behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. HYPOTHESIS: By carefully modulating the preservation environment, it may be possible to preserve osteochondral allograft tissue over the long term while maintaining its original mechanical and biochemical properties. STUDY DESIGN: Controlled laboratory study. METHODS: In this study, juvenile bovine, mature bovine, and canine cartilage explants were cultured in chemically defined media with or without supplementation of dexamethasone for up to 4 weeks. RESULTS: The mechanical properties and biochemical content of juvenile bovine explants cultured in the presence of dexamethasone were significantly enhanced after 2 weeks in culture and remained stable with sustained cell viability thereafter. In contrast, the mechanical properties and biochemical content of juvenile bovine explants cultured in the absence of the dexamethasone significantly decreased after 2 weeks of culture. The mechanical and biochemical content of mature bovine and canine explants were not significantly affected by the presence of dexamethasone and maintained initial (day 0) mechanical and biochemical properties throughout the entire culture period with or without supplementation of dexamethasone. CONCLUSION: These results suggest that juvenile and mature cartilage explants respond differently to dexamethasone. The functional properties of juvenile cartilage explants can be maintained in vitro through the addition of dexamethasone to culture media. Functional properties of mature cartilage can be preserved for at least 4 weeks in culture regardless of the presence of dexamethasone. CLINICAL RELEVANCE: Biochemical and biomechanical properties of osteochondral allograft tissue may be enhanced by the addition of dexamethasone to culture media. These findings may translate to longer shelf life of preserved osteochondral allograft transplantation tissue and increased clinical availability of grafts.

Unique treatment regimen for effort thrombosis in the nondominant extremity of an overhead athlete: a case report.

OBJECTIVE: To advise athletic trainers on the potential for effort thrombosis to occur in nonthrowing athletes and to underscore the importance of early recognition and treatment. BACKGROUND: An 18-year-old offensive lineman presented with a 1-day history of diffuse shoulder pain with no specific history of injury; swelling and erythema involved the entire left upper extremity. He was immediately referred to the team physician, who suspected deep vein thrombosis and sent the athlete to an imaging center. Duplex ultrasound was obtained on the day of presentation, and he was admitted to the hospital that evening. DIFFERENTIAL DIAGNOSIS: Deep vein thrombosis, thoracic outlet syndrome, shoulder tendinitis. TREATMENT: Anticoagulation with heparin was administered at the hospital, and he was sent home the next day on subcutaneous enoxaparin sodium, followed by a 5-mg daily dose of oral warfarin sodium. Oral anticoagulants were continued for a total of 4 weeks. The athlete began upper body lifting and was released 5 weeks postinjury to gradually return to football without restrictions. UNIQUENESS: Effort thrombosis is typically seen in the dominant arm of athletes, and the current treatment protocol calls for thrombolysis or surgical intervention. This athlete, whose position required repeated elevation of his arms in forward flexion, sustained the injury in his nondominant arm, was treated with anticoagulation only, and had a full return to football. At 18-month follow-up, he had no recurrence of symptoms. CONCLUSIONS: Early recognition and treatment of athletes with effort thrombosis is paramount to a successful clinical outcome and prompt return to play.

Concomitant meniscal allograft transplantation and autologous chondrocyte implantation: minimum 2-year follow-up.

BACKGROUND: Although recent studies have shown intermediate-term success of both meniscal allograft transplantation (MAT) and autologous chondrocyte implantation (ACI) performed separately, there have been no peer-reviewed studies focused prospectively on the combined procedure. By potentially reestablishing a compartment contact area closer to normal, MAT may allow a more optimal environment for ACI by reducing stress (stress =force/unit area). On the other hand, the literature suggests that MAT alone in the presence of extensive chondrosis performs poorly. Restoring the articular cartilage may allow the MAT to perform more similarly to series with nearly normal articular cartilage. HYPOTHESIS: Performed concomitantly, ACI and MAT will result in significant improvements in knee function as measured by functional scoring scales and visual analog pain scales. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Preoperative and postoperative comparisons of Browne modified Cincinnati functional levels, Lysholm, visual analog rest and maximum pain, and satisfaction scores were recorded. Thirty-six total procedures were performed between 1999 and 2004. RESULTS: Of the 36 patients entering the series, 29 had >2-year evaluation and scores. Four patients were recorded as failures before the 2-year follow-up and required revision surgery. Three patients were lost to follow-up. A total of 21 medial and 8 lateral MAT/femoral condyle ACIs were performed. Sixteen of 29 patients had concomitant procedures performed, including tibial tuberosity osteotomy, anterior cruciate ligament reconstruction, and high tibial osteotomy. Patients demonstrated statistically significant improvement in the standardized outcome surveys, visual analog pain, and satisfaction scores. The Browne Cincinnati (Patient and Clinician, respectively) showed an improvement from 3.9 (standard deviation [SD], 1.5) and 4.0 (SD, 1.4) preoperatively to 6.3 (SD, 1.9) postoperatively for both. The Lysholm also showed an improvement from 57.7 (SD, 16.2) preoperatively to 77.7 (SD, 19.3) postoperatively. There were no significant differences noted in any of the subgroups (medial vs lateral, isolated vs concomitant, or unipolar vs bipolar). CONCLUSION: At a minimum of 2-year follow-up, MAT in combination with ACI demonstrates improvement in both symptoms and knee function. However, the improvements are less than literature-reported outcomes of either procedure performed in isolation.

Assessment of cellular, biochemical, and histologic effects of bipolar radiofrequency treatment of canine articular cartilage.

OBJECTIVE: To assess the cellular, biochemical, and histologic effects of bipolar radiofrequency-generated heat on canine articular cartilage. SAMPLE POPULATION: Articular cartilage explants (n = 72) from 6 canine cadavers and cultured articular chondrocytes from 5 canine cadavers. PROCEDURE: Cartilage explants were randomly assigned to receive no treatment or treatment with focal (3 seconds) or diffuse bipolar radiofrequency. Following treatment, methylene blue permeability assay was performed (n = 12) and remaining samples (60) were cultured. Immediately and 5, 10, and 20 days after treatment, cultured explants were assessed for glycosaminoglycan (GAG) and collagen contents, type II collagen and matrix metalloproteinase (MMP)-13 immunoreactivity, and modified Mankin histologic scores. Liquid culture media were collected every 4 days and GAG content measured. Additionally, cultured chondrocytes were exposed for 3 seconds to media preheated to 37 degrees, 45 degrees, or 55 degrees C. Cell viability was determined via 2 different assays immediately and 24 hours after treatment. RESULTS: Radiofrequency-treated cartilage had reduced permeability and considerable histologic damage, compared with control samples; most treated samples had reduced collagen II staining and increased MMP-13 immunostaining. Compared with other treatments, less GAGs were released from cartilage after diffuse radiofrequency treatment throughout the study period. Cell viability was significantly different between controls and cells treated at 55 degrees C immediately and 24 hours after heat treatment. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, bipolar radiofrequency treatment had detrimental effects on normal articular cartilage cells and extracellular matrix with probable long-term clinical consequences. The usefulness of radiofrequency for treatment of osteoarthritic articular cartilage requires further investigation.

Bipolar and monopolar radiofrequency treatment of osteoarthritic knee articular cartilage: acute and temporal effects on cartilage compressive stiffness, permeability, cell synthesis, and extracellular matrix composition.

The cellular, biochemical, biomechanical, and histologic effects of radiofrequency-generated heat on osteoarthritic cartilage were assessed. Articular cartilage explants (n=240) from 26 patients undergoing total knee arthroplasty were divided based on Outerbridge grade (I or II/III) and randomly assigned to receive no treatment (controls) or monopolar or bipolar radiofrequency at 15 or 30 W. Both potentially beneficial and harmful effects of radiofrequency treatment of articular cartilage were noted. It will be vital to correlate data from in vitro and in vivo study of radiofrequency thermal chondroplasty to determine the clinical usefulness of this technique.

Surfactant wound irrigation for the treatment of staphylococcal clinical isolates.

Deep wound infection involving an implanted biomaterial is a devastating complication in orthopaedic surgery. Two-thirds of such infections are monomicrobial and the most commonly isolated bacteria in human osteomyelitis and orthopaedic device infection are Staphylococcus aureus and Staphylococcus epidermidis. The purpose of the current study was to examine the effectiveness of the previously reported sequential surfactant irrigation protocol against human-isolated clinical strains of Staphylococcus aureus and Staphylococcus epidermidis in the rat model of orthopaedic implant contamination. The infectivity rate of human-isolated clinical strains of Staphylococcus aureus in a contaminated complex orthopaedic wound was reduced effectively by a sequential surfactant irrigation protocol. Also, in this model, the infectivity of Staphylococcus epidermidis was reduced by normal saline irrigation alone when compared with no irrigation. Therefore, the sequential surfactant irrigation protocol may represent an effective method of wound irrigation in monomicrobial Staphylococcus aureus orthopaedic implant contamination, and normal saline irrigation may suffice in cases of monomicrobial Staphylococcus epidermidis contamination. Additional studies are necessary to determine the clinical use of surfactant irrigation.