Yoon-Seok Youm

Modified Transtibial Versus Anteromedial Portal Technique in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Femoral Tunnel Position and Clinical Results

Background: Although several studies have compared a conventional transtibial technique with an anteromedial (AM) portal technique for single-bundle (SB) anterior cruciate ligament (ACL) reconstruction, no study to date has investigated whether the modified transtibial technique results in the femoral tunnel being in a similar anatomic position and produces similar clinical outcomes with those of the AM portal technique. Purpose: To compare the clinical outcomes and femoral tunnel position of SB ACL reconstruction using a modified transtibial technique (creating a femoral tunnel with varus and internal rotation of the tibia as well as modification of the tibial tunnel orientation) with those of SB ACL reconstruction using an AM portal technique. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 40 patients (40 knees) who underwent arthroscopic SB ACL reconstruction were included in this study. Patients were randomized using a computer-generated sequence into 2 groups: 20 patients by the modified transtibial technique (group 1) and 20 patients by the AM portal technique (group 2). Clinical evaluations included the 2000 International Knee Documentation Committee (IKDC) subjective knee score, Lysholm knee score, Tegner activity scale, Lachman test, pivot-shift test, 2000 IKDC knee examination, and KT-1000 arthrometer measurement. Three-dimensional computed tomography scans were analyzed according to the quadrant method, and the obliquity of the femoral tunnels in the coronal and sagittal planes and the size of the tunnel orifice were measured. Results: All clinical parameters improved significantly after SB ACL reconstruction, with no between-group differences. The mean distance of the femoral tunnel center location from the posterior condylar surface (0.8% difference; P = .167) and from the Blumensaat line (2.1% difference; P = .067) was similar in groups 1 and 2. The mean coronal obliquity of the femoral tunnel was significantly lower in group 1 than in group 2 (42.5° ± 6.1° vs 49.3° ± 7.2°, respectively; P = .001), but the mean sagittal obliquity was similar between the 2 groups (41.9° ± 6.1° vs 43.3° ± 5.4°, respectively; P = .303). The mean area of the tunnel orifice was significantly greater in group 1 than in group 2 (11.6 ± 1.4 × 9.2 ± 1.6 mm vs 10.3 ± 1.1 × 9.1 ± 1.4 mm, respectively; P = .013). Conclusion: The modified transtibial technique for SB ACL reconstruction showed good clinical results and anatomic placement of the femoral tunnel, similar with those of the AM portal technique.

3D CT analysis of femoral and tibial tunnel positions after modified transtibial single bundle ACL reconstruction with varus and internal rotation of the tibia.

INTRODUCTION We analyzed the location of femoral and tibial tunnels by three-dimensional (3D) CT reconstruction images after modified transtibial single bundle (SB) anterior cruciate ligament (ACL) reconstruction, creating a femoral tunnel with varus and internal rotation of the tibia. MATERIAL AND METHODS Data from 50 patients (50 knees) analyzed by 3D CT after modified transtibial SB ACL reconstructions were evaluated. 3D CT images were analyzed according to the quadrant method by Bernard at the femur and the technique of Forsythe at the tibia. RESULTS The mean distance of the femoral tunnel center locations parallel to the Blumensaats line was 29.6%±1.9% along line t measured from the posterior condylar surface. The mean distances perpendicular to the Blumensaats line were 37.9%±2.5% along line h measured from the Blumensaats line. At the tibia, the mean anterior-to-posterior distance for the tunnel center location was 37.8%±1.2% and the mean medial-to-lateral distance was 50.4%±0.9%. DISCUSSION The femoral and tibial tunnels after modified transtibial SB ACL reconstruction creating a femoral tunnel with varus and internal rotation of the tibia (figure-of-4 position) were located between the anatomical anteromedial and posterolateral footprints.

Relation Between Mucoid Degeneration of the Anterior Cruciate Ligament and Posterior Tibial Slope

PURPOSE The purpose was to analyze the association between posterior tibial slope (PTS) and mucoid degeneration of the anterior cruciate ligament (ACL). METHODS From October 1999 to May 2010, 84 arthroscopies were performed in 82 patients (18 men and 64 women) with mucoid degeneration of the ACL. The mean patient age was 53 years (range, 25 to 75 years). In addition to this patient group (group I), the study included a control group without mucoid degeneration of the ACL that was randomly matched for age, sex, body mass index, left or right side, and associated lesions (group II). For each group, the diagnosis was made by use of magnetic resonance imaging and arthroscopy, and a plain lateral radiograph was used to measure the PTS. RESULTS The mean PTS was 13.5° ± 2.6° (range, 8.2° to 19.5°) in group I and 9.4° ± 2.5° (range, 4.8° to 15.5°) in group II. The mean PTS in group I was significantly greater than that in group II (P < .001). For group I, the mean PTS of the involved knee was significantly greater than that of the uninvolved contralateral knee (P = .044). There were no differences according to age, sex, left or right side, body weight, and body mass index (P > .05). CONCLUSIONS Mucoid degeneration of the ACL was found to be associated with an increased PTS. The patients with mucoid degeneration of the ACL had a greater mean PTS than matched control patients (13.5° v. 9.4°, P < .001). LEVEL OF EVIDENCE Level III, diagnostic study of nonconsecutive patients without consistently applied gold standard.

Migration of Polyethylene Fixation Screw After Total Knee Arthroplasty

Duracon (Howmedica, Rutherford, NJ) posterior stabilized total knee system has a snap fit locking mechanism of a tibial polyethylene, including an additional locking screw for further fixation of polyethylene. We report 13 cases of locking screw migration from tibial component after Duracon posterior stabilized primary total knee arthroplasty. Among 13 knees, screw migration in 10 asymptomatic cases was incidentally detected during regular follow-up, and they were just observed in the outpatient clinic. Only 3 knees had moderate pain, swelling, and instability, and revision was done on 2 of 3 knees.

Mucoid Degeneration of Both ACL and PCL

Unlike meniscal tears and chondral defects, the mucoid degeneration of the anterior cruciate ligament (ACL) is a rare cause of knee pain and there have been no case reports of mucoid degeneration of both the ACL and the posterior cruciate ligament (PCL). A 48-year-old-male patient presented with knee pain and limitation of motion. The patients magnetic resonance imaging, arthroscopic findings, and pathologic diagnosis confirmed a clinical diagnosis of mucoid degeneration of both the ACL and the PCL. The symptoms disappeared after arthroscopic partial excision of the ACL and PCL.

Can We Use the Posterior Condylar Off set as a Predictive Factor for Overhang of the Implant in Total Knee Arthroplasty

Purpose We tried to demonstrate whether the posterior condylar offset (PCO, the distance from the femoral diaphysis posterior cortex to the posterior condylar margin) and ratio (PCOR, dividing PCO by the maximum antero-posterior diameter of the distal femur) could be used as predictive factors for overhang of the implants or using gender implants in total knee arthroplasty (TKA). Materials and Methods One hundred and one women who underwent TKA using NexGen® (LPS) implants, were analyzed prospectively. After distal femoral resection, the mediolateral (ML) width was measured at four points (anterior, distal anterior, distal posterior and posterior) and compared with the ML width of the implant. The aspect ratio (AR, ML/AP ratio) and anterior/distal posterior ML width (Ant/DP) were calculated. Preoperative radiographic PCO and PCOR were measured. Differences of PCO, PCOR, AR and Ant/DP according to the size were analyzed and correlations between PCO, PCOR and AR were also analyzed. The patients were classified into two groups according to the presence of overhang, and differences of each parameter were compared between the two groups. Results The size of the implant was positively correlated PCO, not significantly correlated with PCOR, and negatively correlated with AR and Ant/DP. PCO and PCOR and AR showed no correlation with each other. PCO and PCOR were not significantly different between the two groups. However, AR and Ant/DP were statistically low in the group with overhang. Conclusions Preoperative radiographic PCO or PCOR could not be used as a predictive factor for overhang of the implants or using gender implants in TKA.

The expression of vascular endothelial growth factor and Syndecan-4 in cartilage from osteoarthritic knees

Previous studies support the important role of vascular endothelial growth factor (VEGF) and syndecan-4 in the pathogenesis of osteoarthritis (OA). Both VEGF and syndecan-4 are expressed by chondrocytes and both are involved in the regulation of matrix metalloproteinase-3, resulting in the activation of aggrecanase II (ADAMTS-5), which is essential in the pathogenesis of OA. However, the relationship between VEGF and syndecan-4 has not been established. As a pilot study, we assayed the expression of VEGF and syndecan-4 in cartilage samples and cultured chondrocytes from osteoarthritic knee joints and analysed the relationship between these two factors. Specimens were collected from 21 female patients (29 knees) who underwent total knee replacement due to severe medial OA of the knee (Kellgren-Lawrence grade 4). Articular cartilage samples, obtained from bone and cartilage excised during surgery, were analysed and used for chondrocyte culture. We found that the levels of expression of VEGF and syndecan-4 mRNA did not differ significantly between medial femoral cartilage with severe degenerative changes and lateral femoral cartilage that appeared grossly normal (p = 0.443 and 0.622, respectively). Likewise, the levels of expression of VEGF and syndecan-4 mRNA were similar in cultured chondrocytes from medial and lateral femoral cartilage. The levels of expression of VEGF and syndecan-4 mRNAs were significantly and positively correlated in cartilage explant (r = 0.601, p = 0.003) but not in cultured chondrocytes. These results suggest that there is a close relationship between VEGF and syndecan-4 in the cartilage of patients with OA. Further studies are needed to determine the exact pathway by which these two factors interact in the pathogenesis of OA.

Relationship between Mucoid Degeneration of the Anterior Cruciate Ligament and Posterior Tibial Slope in Patients with Total Knee Arthroplasty

Purpose The purpose was to analyze the relationship between posterior tibial slope (PTS) and mucoid degeneration of the anterior cruciate ligament (ACL) in patients with total knee arthroplasty. Materials and Methods Four hundred and twenty-four patients (24 males and 400 females; 636 knees) who received total knee arthroplasty for osteoarthritis were included. Their mean age was 68.9 years (range, 48 to 88 years). The patients were classified into three groups according to the status of ACL; normal ACL group (group I), mucoid degeneration of ACL group (group II) and ruptured or absent ACL group (group III). Plain lateral radiographs were used to measure the PTS and the values were compared among groups. Results There were no significant differences with regard to gender, age and left-to-right side ratio among groups (p>0.05). The mean PTS was 9.9° (range, 0.6° to 20.1°) in group I (161 knees), 10.8° (range, 0.2° to 21.8°) in group II (342 knees) and 12.3° (range, 2° to 22.2°) in group III (133 knees), which showed significant differences (p<0.001). Conclusions The patients with mucoid degeneration of the ACL and those with ruptured or absent ACL had greater PTS than those with normal ACL. These findings suggest that an increased PTS may be one of the causative factors for mucoid degeneration of the ACL.

Synovial fluid levels of TWEAK and matrix metalloproteinase 1 in patients with osteoarthritis, and associations with disease severity:

Purpose: This study assessed the levels of soluble tumor necrosis factor–like weak inducer of apoptosis (TWEAK) and matrix metalloproteinase 1 (MMP-1) in the synovial fluid from osteoarthritic knees to determine their role as well as the relationship between these levels and the severity of osteoarthritis (OA). Methods: Synovial fluid was obtained from 44 knees of 40 patients. The Kellgren–Lawrence (KL) grade was measured using radiograph. The concentration of TWEAK and MMP-1 in the synovial fluid was assessed by enzyme-linked immunosorbent assay. The underlying inflammatory factors (erythrocyte sedimentation rate and C-reactive protein) were also measured. We analyzed the correlation between the factors measured. In addition, the samples were subdivided into three groups according to OA severity using the KL grade, and the differences in TWEAK and MMP-1 levels between groups were analyzed. Results: The TWEAK and MMP-1 levels in the synovial fluid showed a positive correlation with each other. The TWEAK and MMP-1 levels were compared between the three groups according to the KL grade, and the levels showed a significant difference. A post hoc test demonstrated that the group with advanced OA showed a lower concentration of both factors when compared to groups with early OA. Conclusion: The concentration of TWEAK and MMP-1 in the synovial fluid were relatively high in the early stage of OA, and the levels decreased as the OA progressed.

Bilateral Hypoplasia of the Medial and Lateral Menisci

Hypoplasia of the meniscus is a very rare congenital abnormality, with only a few cases reported to date. A 9-year-old girl visited our hospital due to lateral knee pain following a hyperextension injury to the left knee. Magnetic resonance imaging showed hypoplasia of the medial and lateral menisci, as well as a posterior horn tear of the lateral meniscus, in both knee joints. To our knowledge, this is the first report of a patient with hypoplasia of the medial and lateral menisci in both knee joints.