Does the lateral intercondylar ridge disappear in ACL deficient patients?

The aim of this study was to determine whether there is a difference in the presence of the lateral intercondylar ridge and the lateral bifurcate ridge between patients with sub-acute and chronic ACL injuries. We hypothesized that the ridges would be present less often with chronic ACL deficiency. Twenty-five patients with a chronic ACL injury were matched for age and gender to 25 patients with a sub-acute ACL injury. The lateral intercondylar ridge and lateral bifurcate ridge were scored as either present, absent, or indeterminate due to insufficient visualization by three blinded observers. The kappa for the three observers was .61 for the lateral intercondylar ridge and .58 for the lateral bifurcate ridge. The lateral intercondylar ridge was present in 88% of the sub-acute patients and 88% of the chronic patients. The lateral bifurcate ridge was present in 48% of the sub-acute and 48% of the chronic patients. This matched-pairs case-control study was unable to show a difference in the presence of the femoral bony ridges between patients with acute and chronic ACL injuries. The authors would suggest looking for the ridges as a landmark of the native ACL insertion site during ACL reconstruction in both acute and chronic ACL injuries.

Arthroscopic evaluation of radiofrequency chondroplasty of the knee.

BACKGROUND: Considerable debate exists over the use of radiofrequency-based chondroplasty to treat partial-thickness chondral defects of the knee. This study used second-look arthroscopy to evaluate cartilage defects previously treated with bipolar radiofrequency-based chondroplasty. HYPOTHESIS: Partial-thickness articular cartilage lesions treated with bipolar radiofrequency-based chondroplasty will show no progressive deterioration. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: One hundred ninety-three consecutive patients underwent bipolar radiofrequency-based chondroplasty over 38 months; 15 (25 defects treated with bipolar radiofrequency-based chondroplasty) underwent repeat arthroscopy for recurrent or new injuries. Time from the initial to repeat arthroscopy ranged from 0.7 to 32.7 months. At both procedures, the location, size, grade, and stability of lesions were evaluated, recorded, and photographed arthroscopically. RESULTS: At the initial procedure, 25 lesions treated using bipolar radiofrequency-based chondroplasty ranged from 9 to 625 mm2 (mean, 170.2 +/- 131.2 mm2; median, 120 mm2); at second look, lesion size was 9 to 300 mm2 (mean, 107.7 +/- 106.7 mm2; median, 100 mm2). At second look, 3 (12%) demonstrated unstable borders with damage in the surrounding cartilage that appeared to be progressive. Eight (32%) lesions were unchanged in size. Eight (32%) demonstrated partial filling with stable repair tissue, and 6 (24%) demonstrated complete filling with stable repair tissue. Lesions in the tibiofemoral compartments showed better response to radiofrequency chondroplasty than did those within the patellofemoral joint (P < .05). CONCLUSION: Only 3 of 25 lesions demonstrated progression. More than 50% showed partial or complete filling of the defect. Bipolar radiofrequency chondroplasty is an effective way to treat partial-thickness cartilage lesions; however, long-term effects of this treatment on cartilage remain unknown.

Distraction arthroplasty.

Few joint-preserving surgical options exist for the patient who has ankle arthritis refractory to conservative measures. Therefore, continuous effort is afforded to the development of additional treatment options for such patients. Distraction arthroplasty has been proposed as one of these options for the patient in whom fusion or joint replacement is not appropriate. Although the mechanism of action remains unknown, the reports of several researchers support the potential beneficial effects that can be obtained from joint distraction arthroplasty in the severely osteoarthritic ankle. Furthermore, the studies published to date suggest that these effects may not only persist for years but also improve as time progresses during the first several years after treatment. Although additional laboratory studies are needed to understand the biochemical and biomechanical effects of distraction, additional prospective clinical studies are also needed to further understand its efficacy and appropriate patient population. The data thus far suggests that joint distraction arthroplasty may be a viable alternative treatment to arthrodesis and replacement for the young patient who has a congruent, painful, mobile, arthritic ankle joint.

Tissue engineered cartilage integration to live and devitalized cartilage: a study by reflectance mode confocal microscopy and standard histology.

This study investigated the in vivo formation of engineering cartilage within living or devitalized cartilage discs using reflectance mode confocal microscopy and conventional light microscopy. Pig articular chondrocytes were suspended in fibrin glue and placed between two cartilage discs. Four experimental groups were prepared: in groups 1 and 2, the cell-hydrogel composite was placed between two live or between two devitalized cartilage discs, respectively; in groups 3 and 4, acellular fibrin glue was placed between two live or between two devitalized cartilage discs, respectively. Samples were implanted in the back of nude mice and analyzed after 2, 5, and 8 weeks. Results showed that engineered cartilage seems to grow more homogenously when the cell-seeded gel was placed between devitalized cartilages than when it was placed between live cartilage matrices. Confocal microscopy provides valuable information on the integration of tissue-engineered cartilage with native tissue and could be useful for nondestructive imaging in vivo.

Producing a flexible tissue-engineered cartilage framework using expanded polytetrafluoroethylene membrane as a pseudoperichondrium.

BACKGROUND: Both native and engineered cartilage is brittle and fractures easily without perichondrium. The aim of this study was to understand the role of the perichondrium and try to enhance the flexible properties of tissue-engineered cartilage using expanded polytetrafluoroethylene (ePTFE) membrane as a pseudoperichondrium. METHODS: The study was conducted in two phases. In phase I, native swine auricular cartilage of different thicknesses was studied by histologic evaluation and failure testing. Next, isolated perichondrium was bonded to native cartilage slices using fibrin glue or Dermabond and tested to failure. In phase II, swine auricular chondrocytes were suspended in fibrin glue. The chondrocyte-fibrin glue composites were then bound to expanded polytetrafluoroethylene membrane in two trilaminar configurations: In group EC-1, the membrane was in the center, whereas it was on the surfaces in group EC-2. Specimens were implanted into nude mice for 4 weeks, 8 weeks, 12 weeks, and 8 months and subjected to histologic evaluation and failure testing. RESULTS: In phase I, the results demonstrated that perichondrium securely bonded to the cartilage plays an important role in maintaining the flexible nature of elastic cartilage. In phase II, failure testing revealed that specimens in group EC-1 (expanded polytetrafluoroethylene core) were fractured during bending and destroyed after torsion, whereas those in group EC-2 (cartilage core) returned to their original shape without fracturing even after rigorous torsion. Histologic analysis demonstrated that transplanted chondrocytes penetrated into the microporous structure of expanded polytetrafluoroethylene and created a bond to it. CONCLUSION: It is possible to engineer flexible cartilage using expanded polytetrafluoroethylene as a pseudoperichondrium.

Cell-based therapy for meniscal repair: a large animal study.

BACKGROUND: The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously. HYPOTHESIS: Cell-based therapy is able to repair a lesion in the swine meniscus. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the avascular portion of the left medial meniscus of 4 pigs. Autologous chondrocytes were seeded onto devitalized allogenic meniscal slices and were secured inside the lesion with two sutures. Identical incisions were created in 12 other pigs, which were used as three separate control groups: 4 animals treated with an unseeded scaffold, 4 were simply sutured, and 4 were left untreated. Meniscal samples were collected after 9 weeks, and the samples were analyzed grossly, histologically, and histomorphometrically. RESULTS: Gross results showed bonding of the lesion margins in the specimens of the experimental group, whereas no repair was noted in any of the control group specimens. Histological and histomorphometrical analysis showed multiple areas of healing in the specimens of the experimental group. CONCLUSIONS: This study demonstrated the ability of seeded chondrocytes to heal a meniscal tear. CLINICAL RELEVANCE: Cell-based therapy could be a potential tool for avascular meniscus repair.