Good healing potential of patellar chondral defects after all-arthroscopic autologous chondrocyte implantation with spheroids: a second-look arthroscopic assessment.

PURPOSE: To report second-look arthroscopic assessment after all-arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage defects at the patella. METHODS: A second-look arthroscopy after all-arthroscopic ACI using chondrospheres® (ACT3D) was performed in 30 patients with 30 full-thickness retropatellar cartilage defects. The mean time from ACI to second-look arthroscopy was 14.9 ± 16.3 (6-71) months. The quality of cartilage regeneration was evaluated by the International Cartilage-Repair Score (ICRS)-Cartilage Repair Assessment (CRA). RESULTS: Eleven lesions (36.7%) were classified as CRA grade I (normal) and 19 lesions (63.3%) as grade II (nearly normal). Concerning the degree of defect repair, 25 lesions (83.3%) were repaired up to the height of the surrounding articular retropatellar cartilage. Five lesions (16.7%) showed 75% repair of defect depth. The border zone was completely integrated into the surrounding articular cartilage shoulder in 28 lesions (93.3%) and demarcated within 1 mm in 2 lesions (6.7%). Macroscopically and by probing, 12 lesions (40%) had intact smooth surface, 17 lesions (56.7%) had fibrillated surface and 1 lesion (3.3%) had small, scattered fissures. A negative correlation was found between the overall repair assessment score and the defect size (r2 = - 0.430, p = 0.046) and between integration into border zone and defect size (r2 = - 0.340, p = 0.045). A positive correlation was found between macroscopic appearance and age (r2 = + 0.384, p = 0.036). CONCLUSIONS: All-arthroscopic ACI using chondrospheres® (ACT3D) for full-thickness retropatellar articular cartilage defects proved to be reproducible and reliable. The advantage of the procedure is that it is minimal invasive. Arthroscopic second-look demonstrated a high grade of normal or nearly normal cartilage regeneration. Although statistically significant differences were not observed, larger defect size and younger age may compromise the result of overall repair. LEVEL OF EVIDENCE: III.

The evaluation of degeneration of posterior cruciate ligament using CT Hounsfield unit in knee osteoarthritis.

BACKGROUND: Posterior cruciate ligament (PCL) degeneration is often seen in knee osteoarthritis (OA); however, there is no established method for its evaluation. The purpose of this study is to investigate whether the Hounsfield unit (HU) using computed tomography (CT) could be a useful scale to evaluate the degeneration of PCL in knee OA. METHODS: Knee OA treated with total knee arthroplasty (21 patients, 21 knees) and non-osteoarthritic knees (21 patients, 21 knees) were retrospectively observed and studied. All PCLs in the knees were analyzed using CT. The PCL in the sagittal section was divided into three regions: proximal, middle, and distal sections. The HU value of the PCL at each area was measured. In osteoarthritic knees, tissues from the PCL were collected and histologically graded. The correlation between the radiological classification by Kellgren and Lawrence and the histological grade was analyzed. The average CT HU values for each degenerative grade were also calculated and compared. RESULTS: The HU values in OA and non-OA were 70.7 and 88.4 HU (p < 0.05) at the proximal region, 75.7 and 85.3 HU (p < 0.05) in the central region, and 82.3 and 86.5 HU (p > 0.05) in the distal region, respectively. The degeneration of PCL was graded as follows: one, three, and 17 mild, moderate, and severe cases at the proximal portion, and 16, 4, and one mild, moderate, and severe cases at the distal portion, respectively. The radiological classification and the grade of degeneration were not correlated in either the proximal (r = 0.047, p = 0.84) or the distal (r = - 0.21, p = 0.35) portions. The HU value was 84.5, 72.1, and 70.6 HU for mild, moderate, and severe grades, respectively (mild versus moderate: p < 0.05, mild versus severe: p < 0.05, moderate versus severe: p > 0.05). CONCLUSIONS: In knee OA, a lower HU value in the PCL indicates the progression of degeneration. The CT HU value could be a useful measurement to predict the grade of PCL degeneration.

Increase in medial meniscal extrusion in the weight-bearing position observed on ultrasonography correlates with lateral thrust in early-stage knee osteoarthritis.

BACKGROUND: Lateral thrust is known to be risk factors for knee osteoarthritis progression. Medial meniscus extrusion is also known to be risk factors for knee osteoarthritis progression; moreover, the amount of change in medial meniscus extrusion from non-weight bearing to weight bearing is an important factor for the progression of knee osteoarthritis. This study aimed to investigate the correlation between lateral thrust and the change in medial meniscus extrusion. METHODS: In total, 44 knees from 44 patients (mean age, 68.9 years) with knee osteoarthritis were divided into two groups according to the Kellgren-Lawrence grade: early-stage osteoarthritis (Kellgren-Lawrence = 2) and severe osteoarthritis (Kellgren-Lawrence = 3 or 4). The lateral thrust during gait, represented as the lateral acceleration peak immediately after heel strike, was recorded by an inertial sensor. The amount of change in medial meniscus extrusion, which was the difference between weight-bearing (unipedal standing) and non-weight-bearing (supine) conditions, was evaluated using ultrasonography. RESULTS: The mean value of the lateral acceleration peak in the severe osteoarthritis group was higher than that of the early-stage osteoarthritis group (p < 0.05). The non-weight-bearing and weight-bearing medial meniscus extrusion in the severe OA group were significantly higher than those of the early-stage osteoarthritis group (p < 0.001). However, the amount of change in medial meniscus extrusion in severe osteoarthritis group was significantly lower than in the early-stage osteoarthritis group (p < 0.05). The amount of change in medial meniscus extrusion showed a significant correlation with the lateral acceleration peak in the early-stage osteoarthritis group (r = 0.56, p < 0.001). On the other hand, there was no significant correlation in the severe osteoarthritis group. CONCLUSION: The lateral thrust shows a positive correlation with the amount of change in medial meniscus extrusion by weight bearing in patients with early-stage knee osteoarthritis.

Intraoperative Kinematics in Posterior Cruciate Ligament Retaining Total Knee Arthroplasty Using Different Inserts.

We analyzed the intraoperative kinematics of total knee arthroplasty (TKA) using a navigation system to investigate the influence of different inserts on kinematics. This was a retrospective observational study. The Vanguard individualized design (33 patients, 33 knees) XP and anterior-stabilized (AS) inserts were used in TKA for osteoarthritis. Kinematic data were intraoperatively recorded. The range of motion, tibiofemoral rotational angle, anteroposterior translation of the femur, and varus-valgus laxity were compared between the two inserts (XP vs. AS). There was no significant difference in the range of motion (extension: XP, 3.7° ± 3.3° vs. AS, 3.8° ± 3.3°, p = 0.84; flexion: XP, 138.1° ± 10.2° vs. AS, 139.0° ± 13.3°, p = 0.73). With the AS insert, the tibia was gradually internally rotated as the knee was flexed. At maximum extension, the internal rotation was smallest with AS (XP 6.5° ± 4.0° vs. AS 5.1° ± 3.4°, p = 0.022), which was also associated with smaller anterior femoral translation (maximum extension: XP, 14.1 ± 4.8 mm vs. AS, 11.3 ± 4.7 mm, p = 0.00036; 30°: XP, 23.7 ± 5.6 mm vs. AS, 20.7 ± 5.1 mm, p = 0.000033; 45°: XP, 24.4 ± 4.9 mm vs. AS, 23.2 ± 4.5 mm, p = 0.0038). The AS was associated with a lower varus-valgus laxity (30° XP 4.1° ± 3.4 vs. AS 3.3° ± 2.7°, p = 0.036; 60°: XP, 3.2° ± 3.0° vs. AS, 2.4° ± 3.3°, p = 0.0089). The AS insert facilitated sequential tibiofemoral rotation with varus-valgus stability in mid-flexion without restricting the range of motion.

The endoplasmic reticulum stress transducer old astrocyte specifically induced substance positively regulates glial scar formation in spinal cord injury.

To investigate the relationship between endoplasmic reticulum (ER) stress mediated by old astrocyte specifically induced substance (OASIS) and astrogliosis in spinal cord injury (SCI). SCI models were established using adult male mice deficient for OASIS and C57BL/6 (wild-type mice) mice. After SCI, recovery and astrogliosis were examined in the mice at specific time points using functional and histological methods. After SCI, functional recovery was better in the OASIS-deficient mice than in the wild-type mice. OASIS deletion did not inhibit astrocyte migration but reduced the excessive accumulation of N-cadherin-expressing reactive astrocytes that formed the glial scar around the injury site. In addition, OASIS deletion increased the number of serotonin-positive axons in spinal cord regions caudal to the injury site. These findings suggested that the OASIS-mediated ER stress response inhibits the repair of the injured spinal cord by promoting the development of N-cadherin-expressing reactive astrocytes that form glial scars following injury. OASIS deletion inhibited the development of N-cadherin-positive reactive astrocytes that form glial scars and promoted axon growth and functional recovery after SCI. These results suggest that the ER stress response mediated by OASIS could be a new target in the treatment of SCI.

Characteristic morphology of the proximal tibiofibular joint in patients with discoid lateral meniscus.

BACKGROUND: Patients with discoid lateral meniscus (DLM) are prone to meniscal injuries related to its shape and abnormal mobility. The anatomical joint inclination of the proximal tibiofibular joint (PTFJ) can also affect joint movement in knee motion. However, an association between PTFJ morphology and DLM remains unclear. The purpose of this study was to investigate the morphology of the PTFJ on MRI and how this differs between patients with and without DLM. MATERIALS AND METHODS: Fifty-eight patients with DLM and 58 age-matched controls (normal meniscus) were included in this study. Slices from preoperative MRI sagittal images that clearly showed the PTFJ were used for measurements. The angle between the PTFJ and the perpendicular line of the fibula axis was measured as the inclination angle, and patients were classified as horizontal-type (<20°) or oblique-type (>20°). The inclination angle was also compared among patients with open and closed epiphysis in both groups to assess the effect of age. RESULTS: Patients in the horizontal-type PTFJ group frequently had DLM. Before epiphyseal closure, most patients had a horizontal-type PTFJ, with or without DLM. However, in older patients with a closed epiphysis, most with a normal meniscus had an oblique-type PTFJ, and those with DLM retained the horizontal-type joint. CONCLUSION: The horizontal-type PTFJ was significantly associated with DLM, and patients with DLM tended to retain a horizontal-type PTFJ after epiphyseal closure. In contrast, in patients with a normal meniscus, the PTFJ may change from a horizontal-type to an oblique-type PTFJ in line with bone maturity.