Biomedical subjects

Hyunchul Jo

Publications and source records attributed to Hyunchul Jo.

5 recordsLinked to original sources

PubMed2004

Effects of dehydroepiandrosterone on articular cartilage during the development of osteoarthritis.

OBJECTIVE: To investigate the in vivo effects of dehydroepiandrosterone (DHEA) on knee joints during the development of experimentally induced osteoarthritis (OA). METHODS: Twenty-two mature NZW rabbits underwent bilateral anterior cruciate ligament transection (ACLT) and received 0.3-ml intraarticular injections of DHEA (at a concentration of 100 microM in phosphate buffered saline) and control solution in the right and left knees, respectively, beginning 4 weeks after ACLT and continuing once weekly for 5 weeks. All animals were killed 9 weeks after surgery, and the knee joints were assessed by gross morphologic, histologic, histomorphometric, and biochemical methods. RESULTS: Gross morphologic inspection following India ink application showed that the right femoral condyles, which received DHEA, demonstrated less severe cartilage damage than did the contralateral condyles. The thickness, area, and roughness of the DHEA-treated femoral condyles provided evidence of a cartilage-protecting effect of DHEA following ACLT. These results were supported by gene expression analysis. Messenger RNA expression of a proinflammatory cytokine, interleukin-1beta, and catabolic enzymes, matrix metalloproteinases 1 and 3, was reduced in the cartilage of the DHEA-treated knee joints, and expression of tissue inhibitor of metalloproteinase 1 was increased. CONCLUSION: Results of the present study demonstrate a cartilage-protecting effect of DHEA during the development of OA following ACLT in a rabbit model.

Animals↗

PubMed2004

Outcome of anterior cruciate ligament reconstruction using quadriceps tendon autograft.

PURPOSE: The purpose of this study was to determine the outcome of anterior cruciate ligament (ACL) reconstruction using a quadriceps tendon autograft. TYPE OF STUDY: A case series of patients who had received arthroscopic ACL reconstructions using quadriceps tendon autograft was retrospectively evaluated. METHODS: Sixty-seven ACL reconstructions were evaluated at a mean of 41 months (range, 27 to 49 months). Clinical assessment was made using a modified Lysholm score, documentation of International Knee Documentation Committee (IKDC), the anterior knee pain questionnaire of Shelbourne and Trumper, and by KT-2000 arthrometric analysis. Isokinetic strength testing and radiographic assessments were also performed. RESULTS: Arthrometric analysis showed that 63 knees (94%) were graded A or B with a median laxity of 2 mm postoperatively. The Lysholm score improved postoperatively from 71 to 90 ( P < or = .05). Extension peak torque of the quadriceps muscle recovered to 82% and 89% of that of the contralateral knee at 180 degrees/second at 1 year and 2 years after surgery, respectively. The patellar position in terms of congruence angle and Insall-Salvati ratio did not show any significant change. Only 4 patients complained of moderate pain on kneeling and 1 patient complained of harvest-site tenderness. CONCLUSIONS: ACL reconstruction using a quadriceps tendon autograft showed satisfactory results with reduced donor-site morbidities. The quadriceps tendon can be a reliable source of graft, and is comparable to bone-patellar tendon-bone or hamstring tendon in ACL reconstruction. LEVEL OF EVIDENCE: Level IV, Case Series (no, or historical, control group).

Adolescent↗

PubMed2003

Tibial tunnel area changes following arthroscopic anterior cruciate ligament reconstructions with autogenous patellar tendon graft.

We investigated radiographic changes in tibial tunnel area after ACL reconstructions with autogenous patellar tendon grafts on anteroposterior and lateral radiographs over 3 years. Fifty patients followed up for at least 1 year were included in the study. Radiographs were taken on the day of surgery and 3, 6, 9, 12, 24, and 36 months postoperatively. Tibial tunnels on both radiographs were divided into proximal, middle, and distal one-third. The area of each one-third and the greatest diameter of the tibial tunnel on both radiographs was measured using an image-processing software. According to the tunnel area changes, the shape of tibial tunnel was classified into one of four shapes; cylinder, mallet, reverse bottle, and reverse triangle. The correlations between area, diameter and shape of the tunnel, and clinical variables including arthrometer measurement and clinical score were determined. The areas of each one-third of the tibial tunnels on lateral radiographs was always greater than that on anteroposterior radiographs, although the diameters on the two radiographs did not differ significantly. The area of proximal one-third largest and that of distal one-third smallest on both radiographs at any time point. The enlargement and reduction occurred within 3 months and tended to continue for 9 months. Thereafter the tunnel change stabilized on both radiographs. The most common shape of the enlarged tunnels was cylindrical on anteroposterior radiographs reverse triangle on lateral radiographs. No negative effects of enlarged area, diameter, or tunnel shape on clinical results were found in our study.

Adolescent↗

PubMed2003

Analysis of initial fixation strength of press-fit fixation technique in anterior cruciate ligament reconstruction. A comparative study with titanium and bioabsorbable interference screw using porcine lower limb.

We performed a controlled laboratory study to evaluate the initial fixation strength of press-fit technique. Forty porcine lower limbs were used and divided into four groups according to the method of fixation; group 1 (press-fit+1.4 mm), in which the diameter difference between the bone plug and the femoral tunnel was 1.4 mm; group 2 (press-fit+1.4 mm, 30 degrees), in which the diameter difference was the same with group 1, but the tensile loading axis was 30 degrees away from the long axis of the femoral tunnel; group 3 (titanium), in which a titanium interference screw was used for fixation; group 4 (bioabsorbable), in which a bioabsorbable interference screw was used for fixation. The graft in the press-fit group was harvested with a hollow oscillating saw with inner diameter of 9.4 mm to obtain consistent and completely circular shape of the bone plug. The femoral tunnel with diameter of 8 mm was drilled at the original ACL insertion. Following the bone plug insertion into the femoral tunnel and applying a preload of 20 N, the specimen underwent 500 loading cycles between 0 and 2 mm of displacement. Thereafter the specimen was loaded to failure. There was no fixation site failure during the cyclic loading test. Significant differences in the stiffness, linear load, or failure mode among the groups were not found. The average ultimate failure load of group 1 and group 2 were not significantly different from those of group 3 and group 4. The press-fit groups demonstrated sufficient fixation strength for the rehabilitation and interference screw groups. The completely circular shape of the bone plug and increased diameter difference between the bone plug and the femoral tunnel seemed to contribute to the strong fixation.

Animals↗

PubMed2003

Posterolateral reconstruction using split Achilles tendon allograft.

Injury to the cruciate ligaments of the knee commonly occurs in association with posterolateral instability, which can cause severe functional disability including varus, posterior translation, and external rotational instability. Failure to diagnose and treat an injury of the posterolateral corner in a patient who has a tear of the cruciate ligament can also result in the failure of the reconstructed cruciate ligament. Unlike isolated posterior cruciate ligament injury, there seems to be a consensus of opinion that injury to the posterolateral corner, whether isolated or combined, is best treated by reconstructing the posterolateral corner along with the coexisting cruciate ligament injury, if combined. Commonly proposed methods of reconstructing the posterolateral corner have focused on the reconstruction of the popliteus, the popliteofibular ligament, and the lateral collateral ligament. We introduce a new technique for reconstructing the posterolateral corner using a split Achilles tendon allograft. Our method reasonably addresses the several pitfalls in the reconstruction of the posterolateral corner, including (1) concurrent reconstruction of important posterolateral structures, (2) regaining the isometry of the lateral collateral ligament, (3) repositioning the reconstructed popliteus into its original position, and (4) providing a secure fixation method.

Achilles Tendon↗