Clinical features and prognosis of discoid medial meniscus.

PURPOSE: To evaluate the clinical manifestations and the outcome of surgical treatment of discoid medial meniscus. METHODS: Records of 13 patients with discoid medial meniscus were retrospectively reviewed for their epidemiology, clinical manifestations, operation methods, treatment outcome and radiographic characteristics. RESULTS: The 13 cases of discoid medial meniscal injury took up 1.5 ‰ of the overall meniscal injuries treated at our institute during the 44-year period. Patients presented with knee pain (13 patients), giving away (10 patients), swelling (9 patients) and snapping (9 patients). The most common physical signs were medial joint line tenderness (13 patients) and positive McMurray test (11 patients). Ten patients required total meniscectomy. There were excellent short-term results: the median Tegner score was 7, and the mean Lysholm score was 94.8 ± 2.4 at two-year follow-up. However, the long-term outcome was not as good with degenerative changes in the medial compartment of all the involved knees. CONCLUSION: The discoid medial meniscus is extremely rare. The clinical signs and symptoms of discoid medial meniscal injuries are similar to those of any other meniscal injury. No Wrisberg-ligament type abnormality was found. Meniscectomy for discoid medial meniscus produced promising short-term results and deteriorating long-term results with secondary degeneration of cartilage in the medial compartment. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Comparative study of the biological characteristics of mesenchymal stem cells from bone marrow and peripheral blood of rats.

Mesenchymal stem cells (MSCs) from adult exhibit self-renewal and multilineage differentiation capacities, making the MSCs promising candidates for cell therapy and tissue engineering. Although bone marrow (BM) is the most universal source of MSCs, other tissues may also contain MSCs. Peripheral blood (PB), in particular, arises as the most attractive source of MSCs due to easy accessibility and noninvasive procedure. However, it is not certain that PB-MSCs have the equal biological characteristics to those of BM-MSCs. The purpose of this study was to compare the biological characteristics between BM-MSCs and PB-MSCs. We adopted granulocyte colony-stimulating factor combined with CXCR4 antagonist AMD3100 to stimulate MSCs to release into blood circulation of the rats. PB-MSCs were obtained from mobilized PB and expanded in long-term culture. BM-MSCs were isolated from the femur and tibia medullary canal of the same rats by density gradient centrifugation. After cell expansion in vitro, cell surface markers and multipotentiality analysis were performed to identify MSCs. Apoptosis resistance to H(2)O(2)-induced apoptosis, proliferation kinetics, cellular senescence, and karyotype analysis were measured to compare the biological characteristics of PB-MSCs and BM-MSCs. PB-MSCs with the typical adherent fibroblast-like morphology were similar to that of BM-MSCs. Both PB-MSCs and BM-MSCs were positive for CD44 and CD90, and negative for CD34 and CD45. They both exhibited trilineage differentiation potential and expressed lineage-specific genes. Although the BM-MSCs showed stronger osteogenic and adipogenic differentiation, PB-MSCs displayed a more chondrogenic capacity. Further, BM-MSCs have greater proliferation ability. Apoptosis resistance and cellular senescence were similar in MSCs derived from both sources. The results of our study demonstrate that PB-MSCs have similar biological characteristics to those of BM-MSCs despite certain minor differences, suggesting PB as a possible alternative source for MSCs.

Computed tomographic measurement of gender differences in bowing of the sagittal femoral shaft in persons older than 50 years.

Surgeons do not give enough weight to the effects of bowing of the sagittal femoral shaft in total knee arthroplasty (TKA), which can result in damage to the cortex, fractures, or malalignment of the femoral component. To determine gender differences in bowing, we used spiral computed tomography to scan the femurs of 26 men and 47 women older than 50 years who required TKA. Skeletal extraction of the total sagittal femoral shaft from computed tomographic images was done by a matrix laboratory. The extracted curves were evenly divided into 3 sections. Comparison of the curvature on different sections of the same side of the femur showed that the distal third was significantly bowed. In addition, the curvature of the distal third was significantly larger in women than in men. Such morphological characteristics put forward new requirements in how intramedullary guide rods are used in TKA.

The position of the posterolateral bundle femoral tunnel during arthroscopic double-bundle anterior cruciate ligament reconstruction: a cadaveric study.

PURPOSE: The purpose was to find a simple guideline to help establish accurate positioning of the posterolateral bundle (PLB) femoral bone tunnel during double-bundle anterior cruciate ligament reconstruction by measuring the distance between the center of the PLB femoral footprint to the shallow and the deep articular cartilage borders of the lateral wall of the intercondylar notch. METHODS: The femoral insertions of the anteromedial bundle and PLB of the anterior cruciate ligament were dissected in 22 male cadaveric knees, aged 25 to 45 years. By use of the intercondylar notch as the landmark, the distances between the center of the PLB femoral footprint and the shallow and the deep articular cartilage borders of the lateral wall of the intercondylar notch were measured with the knees flexed at 90°. The measured data (mean ± standard deviation) were evaluated and compared. RESULTS: The center of the PLB was positioned 8.60 ± 1.52 mm and 8.65 ± 1.54 mm from the shallow and the deep cartilage borders of the lateral wall of the intercondylar notch, respectively (P = .95). The distance between the center of the PLB footprint to the low cartilage border of the lateral intercondylar wall was 5.05 ± 0.76 mm. CONCLUSIONS: The findings suggest that the position of the center of the PLB femoral footprint is at the middle of the line joining the shallow and the deep borders of the femoral cartilage. CLINICAL RELEVANCE: Surgeons can use our results as a guideline and use the PLB footprint remnant as a reference at the same time to locate the femoral PLB tunnel in a simple, easy, and repeatable way.

Diagnostic values of 3 methods for evaluating meniscal healing status after meniscal repair: comparison among second-look arthroscopy, clinical assessment, and magnetic resonance imaging.

BACKGROUND: The main diagnostic methods for evaluating repaired menisci include second-look arthroscopy, clinical assessment, and magnetic resonance imaging (MRI). None of the previous studies applied all 3 methods for each consecutive case nor made any systematic comparison among them. PURPOSE: This study was undertaken to compare the diagnostic values of the 3 different methods in an attempt to propose suggestions for evaluating meniscal healing results. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Eighty-one patients (89 menisci), with a mean age of 25.4 years (standard deviation [SD], 7.7; range, 15-50 years), underwent arthroscopic meniscal repair, including 65 medial menisci and 24 lateral menisci. Follow-up evaluation for each meniscus included clinical assessment, second-look arthroscopy, and postoperative MRI, with a mean follow-up time of 25.4 months (SD, 6.0; range, 17.4-48.3 months). Defined criteria for unhealed meniscus were any symptoms such as joint-line tenderness, swelling, locking, or positive McMurray test for clinical assessment; cleft or instability on second-look arthroscopy; and grade 3 signal intensity shown at the repaired site on postoperative MRI. RESULTS: Seventy-seven menisci were confirmed completely healed by second-look arthroscopy, with a total healing rate of 86.5%. Clinical assessment found 63 menisci healed, with a clinical healing rate of 70.8% (sensitivity, 58.3%; specificity, 75.3%; accuracy, 73.0%). By using the second-look arthroscopy as the standard, the sensitivity, specificity, and accuracy, respectively, were calculated for MRI in 5 sequences: sagittal T1: 91.7%, 58.4%, 62.9%; sagittal proton density (PD): 83.3%, 40.3%, 46.1%; sagittal T2: 58.3%, 89.6%, 85.4%; coronal PD: 75.0%, 74.0%, 74.2%; and coronal T2: 41.7%, 98.7%, 91.0%. CONCLUSION: Second-look arthroscopy was the most dependable way to determine meniscal healing. Clinical assessment had obvious limitations in diagnosing healed menisci. On MRI examination, T2-weighted sequences had obviously higher specificity and accuracy, while PD and T1 had higher sensitivity. The diagnostic value could be improved by a combined application of different sequences.

Second-look arthroscopic evaluation of the articular cartilage after primary single-bundle and double-bundle anterior cruciate ligament reconstructions.

BACKGROUND: Several reports have shown the progression of articular cartilage degeneration after anterior cruciate ligament (ACL) reconstruction. No report has been published about the cartilage comparing changes after single-bundle (SB) and double-bundle (DB) ACL reconstructions. The purpose of this study was to evaluate the articular cartilage changes after SB and DB ACL reconstructions by second-look arthroscopy. METHODS: Ninety-nine patients who received arthroscopic ACL reconstruction were retrospectively reviewed at an average of 14 months after reconstruction, 58 patients underwent SB ACL reconstruction and 41 patients underwent DB ACL reconstruction. Hamstring tendon autografts were used in all patients. Second-look arthroscopy was done in conjunction with the tibial staple fixation removal at least one year after the initial ACL reconstruction. Arthroscopic evaluation and grading of the articular cartilage degeneration for all patients were performed at the initial ACL reconstruction, and at the second-look arthroscopy. RESULTS: The average cartilage degeneration at the patellofemoral joint (PFJ) was found significantly worsened after both SB and DB ACL reconstructions. This worsening were not seen at medial tibiofemoral joint (TFJ) and lateral TFJ. Grade II cartilage damage was the most common. At second-look arthroscopy, the average patellar cartilage degeneration was 1.14 ± 0.14 (at first look 0.52 ± 0.11) for the SB group, and 1.22 ± 0.15 (at first look 0.56 ± 0.12) for the DB group. The average trochlear cartilage degeneration was 1.05 ± 0.16 (at fist look 0.10 ± 0.06) and 0.66 ± 0.17 (at fist look 0.17 ± 0.09), respectively. The average patellar cartilage degeneration showed no significant difference in both groups. However, the average trochlea cartilage degeneration in DB group was significantly less than in SB group. CONCLUSIONS: Patellofemoral cartilage degeneration continued to aggravate after ACL reconstruction. DB ACL reconstruction could significantly decrease the trochlea cartilage degeneration compared with SB ACL reconstruction.

Proliferation and apoptosis property of mesenchymal stem cells derived from peripheral blood under the culture conditions of hypoxia and serum deprivation.

BACKGROUND: The proliferation and apoptosis property of mesenchymal stem cells derived from peripheral blood (PB-MSCs) were investigated under hypoxia and serum deprivation conditions in vitro so as to evaluate the feasibility for autologous PB-MSCs applications in cartilage repair. METHODS: MSCs were mobilized into peripheral blood by granulocyte colony stimulating factor (G-CSF) and AMD3100. The blood samples were collected from central ear artery of rabbits. Adhered cells were obtained by erythrocyte lysis buffer and identified as MSCs by adherence to plastic, spindle shaped morphology, specific surface markers, differentiation abilities into osteoblasts, adipocytes and chondroblasts in vitro under appropriate conditions. MSCs were cultured in four groups at different oxygen tension (20% O2 and 2% O2), with or without 10% fetal bovine serum (FBS) conditions: 20% O2 and 10% FBS complete medium (normal medium, N), 20% O2 and serum deprivation medium (D), 2% O2 and 10% FBS complete medium (hypoxia, H), 2% O2 and serum deprivation (HD). Cell proliferation was determined by CCK-8 assay. Apoptosis was detected by Annexin V/PI and terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) staining. RESULTS: Spindle-shaped adherent cells were effectively mobilized from peripheral blood by a combined administration of G-CSF plus AMD3100. These cells showed typical fibroblast-like phenotype similar to MSCs from bone marrow (BM-MSCs), and expressed a high level of typical MSCs markers CD29 and CD44, but lacked in the expression of hematopoietic markers CD45 and major histocompatibility complex Class II (MHC II). They could also differentiate into osteoblasts, adipocytes and chondroblasts in vitro under appropriate conditions. No significant morphological differences were found among the four groups. It was found that hypoxia could enhance proliferation of PB-MSCs regardless of serum concentration, but serum deprivation inhibited proliferation at the later stage of culture. Apart from that, hypoxia or serum deprivation could promote the apoptosis of PB-MSCs after 48 hours; the effect was stronger when these two conditions combined together. Furthermore, the effect of serum deprivation on apoptosis was stronger compared with that of hypoxia. CONCLUSIONS: PB-MSCs possess similar phenotypes as BM-MSCs. Their differentiation and proliferation abilities make them a new source of seed cells for ischemia-related cell therapy and tissue engineering in the field of the articular cartilage repair.