An older age, a longer duration between injury and surgery, and positive pivot shift test results increase the prevalence of articular cartilage injury during ACL reconstruction in all three compartments of the knee in patients with ACL injuries.

PURPOSE: To investigate factors that influence the prevalence of articular cartilage injury in patients with anterior cruciate ligament (ACL) injury. METHODS: This multicentre study included patients with ACL injury. Logistic regression analysis was conducted to identify factors that influence the prevalence of cartilage injury during ACL reconstruction. RESULTS: A total of 811 patients were enrolled. The factors that significantly influenced the prevalence of cartilage injury were age (odds ratio [OR], 1.04; P = 0.000), a positive pivot shift test result (OR, 1.43; P = 0.021), medial meniscal injury (OR, 2.55; P = 0.000), and delayed surgery (≥ 12 months) (OR, 2.52; P = 0.028) in the medial compartment of the knee; age (OR, 1.05; P = 0.000), subjective grades of apprehension during the pivot shift test (OR, 1.46; P = 0.010), lateral meniscal injury (OR, 1.98; P = 0.003), femoro-tibial angle (FTA) (OR, 0.92; P = 0.006), and delayed surgery (≥ 12 months) (OR, 2.63; P = 0.001) in the lateral compartment; and age (OR, 1.06; P = 0.000), body mass index (OR, 1.07; P = 0.028), a positive pivot shift test result (OR, 1.60; P = 0.018), FTA (OR, 0.90; P = 0.006), and delayed surgery (≥ 12 months) (OR, 3.17; P = 0.008) in the patellofemoral compartment. CONCLUSION: An older age, a longer duration between injury and surgery, and a positive pivot shift test result were positively associated with the prevalence of cartilage injury in three compartments in patients with ACL injuries. Early ACL reconstruction is recommended to prevent cartilage injury. LEVEL OF EVIDENCE: Level III.

A prospective study of 3-day versus 2-week immobilization period after anterior cruciate ligament reconstruction.

BACKGROUND: Aggressive early rehabilitation is recommended after reconstruction of the anterior cruciate ligament (ACL) using a patellar tendon-bone graft. However, rehabilitation after reconstruction of ACL using the multistranded hamstring is controversial. In this study, we compared the clinical results of 3-day immobilization after reconstruction of ACL using the multistranded hamstring, with those of 2-week immobilization prospectively. METHODS: A total of 30 consecutive patients with ruptured ACL underwent single-socket ACL reconstruction. 10 male and 5 female patients (mean age of 29.2+/-10.0 years) were prospectively randomized for a 3-day immobilization period, and 6 male and 9 female patients (mean age of 27.3+/-10.9 years) were randomized for a 2-week immobilization period. We measured the anterior laxity with a KT-2000 arthrometer, joint position sense, and thigh muscle strength at 3, 6 and 12 months after surgery. RESULTS AND CONCLUSIONS: There were no statistically significant differences between the two groups. We concluded that the post-operative 3-day immobilization period is preferable to the longer 2-week period in our rehabilitation program from the viewpoint of psychological load to the patients and the duration of hospitalization after ACL reconstruction using multistranded hamstring tendons.

In vitro cartilage formation using TGF-beta-immobilized magnetic beads and mesenchymal stem cell-magnetic bead complexes under magnetic field conditions.

We evaluated the efficacy of transforming growth factor (TGF)-beta-immobilized magnetic beads for chondrogenesis in vitro using a mesenchymal stem cell (MSC) delivery system and an external magnetic force (EMF). MSCs isolated from the bone marrow of Sprague Dawley rats were mixed with carboxyl group-combined magnetic beads (Ferri Sphere 100C) coated with anti-rat CD44 mouse monoclonal antibodies. TGF-beta3 (10 and 1 ng/mL) was attached magnetically to such other Ferri Sphere 100C beads via an amide bond formed between a primary amino group on the TGF-beta3 and the carboxyl groups on the surface of the beads. MSC-magnetic bead complexes were centrifuged to form a pellet and cultured in chondrogenic differentiation medium (CDM) supplemented with either 10 or 1 ng/mL TGF-beta-immobilized magnetic beads (10 or 1 ng/mL TGF-beta-immobilized magnetic bead groups) or in CDM supplemented with 1 or 10 ng/mL TGF-beta (1 or 10 ng/mL TGF-beta group). TGF-beta-immobilized magnetic beads were gathered effectively under an EMF. Chondrogenesis was achieved from the MSC-magnetic bead complexes in the presence of 1 ng/mL TGF-beta-immobilized magnetic beads.

The role of the synovium in repairing cartilage defects.

The purpose of this study was to examine the role of the synovium in the transitional zone between the articular cartilage and the synovial membrane in cartilage repair and the relationship between the origin of the repaired cartilage and the grafted synovium. We used 8-week-old Sprague Dawley (SD) rats and green fluorescent protein (GFP) transgenic rats. In study 1, a full-thickness cartilage defect was created at the medial condyle of the femur, and the synovium 5 x 5 mm extending up to the cartilage defect was resected in the left knee (cartilage defect without synovium group) but not resected in the right knee (cartilage defect with intact synovium group). In study 2, after the creation of a full-thickness cartilage defect and resection of the synovium, the synovium of the GFP rats was transplanted into the unilateral knee (cartilage defect with transpl.synovium group). At 2, 4, 6, and 8 weeks after surgery, we evaluated the repaired tissue in cartilage defects histologically and immunohistochemically, and the expression of aggrecan and type II collagen in the repaired tissue was also investigated using reverse transcriptase-polymerase chain reactions (RT-PCR). At 6 and 8 weeks after surgery, the defect was filled with cartilage-like tissue in cartilage defect with intact synovium group and cartilage defect with transpl.synovium group, but not in cartilage defect without synovium group. GFP positive cells were observed in the repaired tissue and the expression of aggrecan and type II collagen was found in cartilage defect with transpl.synovium group. We concluded that the synovium in the transitional zone between the articular cartilage and the grafted synovial membrane invades the cartilage defects where the cells could be detected as GFP-positive cells. Those cells may take part in the repair and may induce chondrogenesis.

The long-term results of meniscus transplantation for articular cartilage defects in the knee joint.

The purpose of this study was to examine the long-term clinical results of meniscus transplantation for articular cartilage defects in the knee joint. The type of study was case series. From October 1990 to June 1995, eight cases underwent allogenic or autogenic meniscus transplantations for articular cartilage defects, and seven cases were available for follow-up evaluations. The age at surgery ranged from 14 to 42 years of age (average 22.5). In one case, transplantation of tissue-engineered cartilage was performed due to pain 5 years after surgery. The other six cases were followed up for 8-13 years (average 10.1). The size of the cartilage defect ranged from 1.0 to 6.3 cm2 (average 2.8 cm2). Patients were evaluated with the Lysholm score and MR images. We also performed arthroscopic examinations in three cases at the final evaluation. This study leads to the conclusion that meniscus transplantation for articular cartilage damage is not comparable to autologous chondrocyte transplantation. Two cases showed a good clinical outcome but the tissue remained as fibrocartilage tissue in the long-term.