Clinical and Magnetic Resonance Imaging Outcomes After Human Cord Blood-Derived Mesenchymal Stem Cell Implantation for Chondral Defects of the Knee.

Background: There is a paucity of literature reporting clinical and magnetic resonance imaging (MRI) outcomes after allogeneic umbilical cord blood-derived mesenchymal stem cell (UCB-MSC) implantation for chondral defects of the knee. Purpose: To report clinical and MRI outcomes after UCB-MSC implantation for chondral lesions of the knee. Study Design: Case series; Level of evidence, 4. Methods: Inclusion criteria were patients aged between 40 and 70 years with focal chondral lesions of grade 3 or 4 on the medial femoral condyle, defect sizes >4 cm2, and intact ligaments. Exclusion criteria were patients who required realignment osteotomy or who had a meniscal deficiency, ligamentous instability, or a concomitant full-thickness chondral defect in the lateral or patellofemoral compartment. A mixture of human UCB-MSCs and sodium hyaluronate was implanted into the chondral defect through mini-arthrotomy. MRI at 1-year follow-up was performed to evaluate repaired cartilage hypertrophy. Repaired cartilage thickness was measured, and hypertrophy was classified as grade 1 (<125%), grade 2 (<150%), or grade 3 (<200%). Patient-reported outcomes (PROs; International Knee Documentation Committee, visual analog scale for pain, and Western Ontario and McMaster Universities Osteoarthritis Index) were evaluated preoperatively and at 1, 2, and 3 years postoperatively. Repaired cartilage hypertrophy was evaluated for a correlation with PRO scores. Results: Enrolled were 85 patients with a mean age of 56.8 ± 6.1 years and a mean chondral defect size of 6.7 ± 2.0 cm2. At follow-up, a significant improvement in all PRO scores was seen compared with preoperatively (P < .001 for all). MRI at 1-year follow-up demonstrated that 28 patients had grade 1 repaired cartilage hypertrophy, 41 patients had grade 2, and 16 patients had grade 3. MRI performed in 11 patients at 2 years after surgery indicated no difference in repaired cartilage hypertrophy between the 1- and 2-year time points. The grade of repaired cartilage hypertrophy did not correlate with PRO scores. Conclusion: Clinical outcomes improved significantly at short-term follow-up after UCB-MSC implantation. Although all patients showed repaired cartilage hypertrophy, it did not correlate with clinical outcomes.

Accuracy of the Arthroscopic Location of the Center of the Anterior Horn During Lateral Meniscal Allograft Transplantation.

Background: Anatomic placement of the meniscal allograft is imperative to achieve satisfactory outcomes after meniscal allograft transplantation (MAT). Few studies have reported on the accuracy of the provisional location of the center of the anterior horn of the lateral meniscus (AHLM). Hypothesis: The authors hypothesized that the provisional center would not coincide with the anatomic center of the AHLM. Study Design: Descriptive laboratory study. Methods: Tibial plateaus were retrieved from 93 consecutive patients who underwent total knee arthroplasty. A complete radial cut was made 2 cm lateral to the insertion of the AHLM on the retrieved tibial plateau. While moving the stump of the anterior horn with forceps, the center of the insertion was determined, and a Kirschner wire (provisional wire) was drilled into the location. The insertion area of the AHLM was dissected carefully, and the periphery of the insertion area of the anterior horn was marked. Another Kirschner wire (anatomic wire) was drilled into the center of the dissected anterior horn. The resected tibial plateau was positioned so that the longitudinal line of the tibial plateau was aligned on a plastic ruler. The distance between the provisional and anatomic wires was measured by a digital caliper along the longitudinal and vertical axes. Results: The mean distance between the provisional and anatomic wires was 2.5 ± 1.2 mm. The provisional wire in 14 patients (15%) was placed at the anatomic center. In 36 patients (39%), the provisional wire was drilled anterolateral to the anatomic center, and in 18 patients (19%), the wire was drilled anteromedial to the anatomic center. In 21 patients (23%), the provisional wire was located within 2 mm of the anatomic center, and in 62 patients (67%), the wire was located within 3 mm of the anatomic center. Conclusion: The provisional wire was located a mean of 2.5 mm from the anatomic center, and only 23% of patients had wires that were located within 2 mm of the anatomic center. In 39% of patients, the provisional wire was drilled anterolateral to the anatomic center. This finding needs to be considered during lateral MAT. Clinical Relevance: Without dissection of the AHLM, the determination of the anatomic center of the anterior horn is not accurate during lateral MAT.

An Increased Lateral Femoral Condyle Ratio in Addition to Increased Posterior Tibial Slope and Narrower Notch Index Is a Risk Factor for Female Anterior Cruciate Ligament Injury.

PURPOSE: To investigate the relationship between the lateral femoral condyle ratio (LFCR) among osseous morphologic characteristics of the knee and anterior cruciate ligament (ACL) injury in female patients. METHODS: Inclusion criteria were female patients (ACL group, n = 59) undergoing primary ACL reconstruction from 2012 to 2018. Control female patients (control group, n = 58) were matched by age, height, and body mass index to ACL group. They had no meniscal or ligament tear, and no trochlear dysplasia on magnetic resonance imaging. The LFCR, notch width index (NWI), and posterior tibial slope (PTS) were measured and compared between the ACL and control groups. For each risk factor, the receiver operating characteristic curve and the area under the curve and its 95% confidence interval (CI) was calculated to determine the cutoff for detecting increased risk of ACL injury. RESULTS: The LFCR was significantly larger in the knees in the ACL group than in the control group (P = .001). The NWI was significantly smaller and the PTS was significantly larger in the knees in the ACL group than in the control group (P = .000, P = .000, respectively). The NWI (odds ratio [OR] 1.41; P = .000) was the most significant factor, followed by the PTS (OR 1.29; P = .003) and the LFCR (OR 1.26; P = .001). The area under the curve (0.67, 95% CI 0.58-0.77) for the LFCR had a sensitivity of 66% and specificity of 66% to predict an ACL injury. The cutoff of 63.9 was associated with an increased risk for ACL injury (OR 3.71; 95% CI 1.73-7.95). CONCLUSIONS: An increased LFCR was associated with female ACL injury. The LFCR, NWI, and PTS are predictive risk factors for an ACL injury. These findings need to be considered for clinician in identifying female patients at risk for an ACL injury. LEVEL OF EVIDENCE: III, retrospective comparative prognostic trial.

Lateral Capsular Stabilization in Lateral Meniscal Allograft Transplantation.

BACKGROUND: Stabilization of the lateral capsule to the tibial plateau may decrease midbody extrusion after lateral meniscal allograft transplantation (MAT). However, there is a paucity of literature reporting on postoperative magnetic resonance imaging (MRI) findings after lateral capsular stabilization (LCS) at the time of lateral MAT. PURPOSE/HYPOTHESIS: The purpose was to describe MRI findings after LCS and compare postoperative extrusion between isolated lateral MAT and lateral MAT with LCS. It was hypothesized that allograft extrusion would be reduced after MAT with LCS but that the stabilized capsule would increase the risk of tears to the capsule or allograft. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Included were patients who underwent lateral MAT with 6-month follow-up MRI. Concomitant LCS was performed for patients with redundant lateral capsule displaced from the lateral tibial plateau as evident on coronal MRI or arthroscopic examination (MAT+LCS group); otherwise, patients underwent MAT only (isolated MAT group). The Lysholm score, Tegner score, and lateral joint space on radiographs were compared between the 2 groups at 2 years postoperatively, and the stabilized lateral capsule and allograft were evaluated using 6-month follow-up MRI. Extrusion, rotation, and position of the allograft bridge were compared between the 2 groups. Regression analysis was performed to identify factors predictive of degree of extrusion. RESULTS: There were 10 patients in the MAT+LCS group and 13 patients in the isolated MAT group. No significant differences were found between groups in preoperative patient characteristics or postoperative Lysholm score, Tegner score, lateral joint space, or MRI parameters. Postoperative extrusion was not related to obliquity angle, position of the bony bridge, or presence of LCS. In the MAT+LCS group, 1 patient showed a tear of the lateral capsule and a radial tear of the allograft, and 3 patients had a meniscocapsular separation at the midbody of the allograft. In the isolated MAT group, 1 patient had a peripheral tear at the midbody, but there was no tear of the allograft in the other patients. CONCLUSION: LCS did not decrease extrusion of lateral meniscal transplantation, but it can lead to increased risk for graft or capsule tear.