Editorial Commentary: Increased Lateral Femoral Condyle Ratio, Increased Posterior Tibial Slope, and Narrow Notch Width Are all Risk Factors for Anterior Cruciate Ligament Tear, and Anterior Cruciate Ligament Graft Tear.

Bony risk factors for anterior cruciate ligament (ACL) injuries have been investigated during past 2 decades. Deep posterior femoral condylar depth, measured by the lateral femoral condyle ratio, influences anterolateral instability and the graft survival following ACL reconstructions. Before planning of revision ACL reconstruction, other bony risk factors, including the posterior tibial slope and intercondylar notch width, should be carefully evaluated to protect the ACL graft.

Tibial-sided Anterolateral Ligament Injuries Are Associated With Poor Healing and Residual Pivot Shift Testing After Anterior Cruciate Ligament Reconstruction.

PURPOSE: To investigate whether tibial-sided anterolateral ligament (ALL) injuries are associated with poor healing and residual pivot shift. METHODS: Patients who underwent anterior cruciate ligament reconstructions within postinjury 6 weeks from January 2008 to March 2021 were included. They had concomitant ALL injury confirmed by preoperative magnetic resonance imaging (MRI) and were followed for a minimum of 20 months. Preoperative ALL injury was graded by the Muramatsu classification, and postoperative ALL healing were graded by a modification of the Lee classification (good, partial, and nonvisualized). The patients were allocated to an improved group (IG) and an unimproved group (UG) on the basis of a comparison of pre- and postoperative MRI. ALL tear site, postoperative knee stability, Lysholm score, and Tegner activity scale (patient-reported outcomes [PROs]) were compared between the 2 groups. RESULTS: In total, 128 patients were enrolled; 94.5% patients achieved the minimal clinically important difference for PROs, respectively. The ALL was torn at the femoral side in 46.9% patients, at midsubstance in 31.2.%, and at tibial side in 21.9%, Preoperatively, 86 (67.2%) patients had a partial tear, and 42 (32.8%) patients had a complete tear. On the basis of the postoperative MRI appearances, 38 (29.7%) and 90 (70.3%) patients were allocated to the IG and UG, respectively. The tibial-side tears were significantly frequent in the UG (P = .032). Pivot shift showed a significantly greater incidence in the UG than IG (P = .004). Lachman test and PROs did not differ between the 2 groups. CONCLUSIONS: Tibial-sided ALL tears occurred in 18.7% of the UG compared with 3.2% of the IG, and 45.6% of the UG had a postoperative grade 1 or 2 pivot shift compared with 15.8% of the IG. Percentages of patients with the minimal clinically important difference for PROs did not differ between the 2 groups. However, the clinical relevance is limited by a high transfer bias. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Editorial Commentary: Determinants of Outcome After Repair of Knee Medial Meniscus Posterior Root Tear Are Multifactorial.

Medial meniscus posterior root tears alter tibiofemoral contact, leading to medial knee osteoarthritis. Repair can restore kinematics and biomechanics. Female sex, age, obesity, high posterior tibial slope, varus malalignment >5°, and Outerbridge grade ≥3 chondral lesions in the medial compartment are associated with risk for medial meniscus posterior root tears and poor healing after repair. Extrusion, degeneration, and tear gap may increase tension across the repair site, resulting in poor outcome.

Combined Anterolateral Ligament and Anterior Cruciate Ligament Injury Is Associated With Increased Lateral Femoral Condyle Ratio.

PURPOSE: to investigate the association between the lateral femoral condylar ratio (LFCR), the posterior tibial slope (PTS), and injury of the anterolateral ligament (ALL). METHODS: Inclusion criteria were patients with acute anterior cruciate ligament (ACL) tear after noncontact injury during sports from October 1997 to May 2021. The LFCR and PTS were measured, and injury of the ALL was evaluated. Patients were divided into 2 groups: isolated ACL tear (isolated group) and combined ACL with ALL tear (combined group). The LFCR and PTS were compared between the isolated and combined groups. For each risk factor, the receiver operating characteristic curve, the area under the curve (AUC), and its 95% confidence interval (CI) were calculated to determine the cutoff for detecting increased risk of ALL injury. RESULTS: There were 83 patients in the isolated group and 176 patients in the combined group. Demographics of the 2 groups did not differ significantly. The LFCR was significantly larger in the combined group than in the isolated group (P = .000). The PTS did not differ between the two groups (P = .405). The LFCR (odds ratio [OR] = 1.58; P = .000) was a significant factor. Age, body mass index, and PTS were not associated with an ALL injury. The AUC (0.79; 95% CI, 0.74-0.85) for the LFCR had a sensitivity of 73% and specificity of 76% to predict an ALL rupture. The calculated cutoff of 64.5 was associated with an increased risk for ALL rupture (OR = 8.65; 95% CI, 4.73-15.81) when compared with the isolated group. CONCLUSIONS: An increased LFCR was associated with the ALL injury. However, increased PTS was not associated with ALL injury. These findings need to be considered for clinicians in treating ACL tear patients at risk for an ALL injury. LEVEL OF EVIDENCE: III, retrospective comparative prognostic trial.

Editorial Commentary: Knee Preoperative Medial Laxity May Result in Overcorrection or Varus Recurrence After Open-Wedge High Tibial Osteotomy.

The long-term results of high tibial osteotomy (HTO) depend mainly on postoperative alignment. However, under- or overcorrection can occur during and after surgery. Biomechanically, excessive overcorrection after HTO can potentially lead to unfavorable knee kinematics and increased shear stress at the joint surface. Fine tuning of the medial soft tissue during open wedge HTO is necessary for a satisfactory limb alignment.

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.

Comparison of Postoperative Tunnel Widening After Hamstring Anterior Cruciate Ligament Reconstructions Between Anatomic and Nonanatomic Femoral Tunnels.

PURPOSE: To evaluate the effect of the location of the femoral tunnel on 3-dimensional (3D) computed tomography (CT) upon the postoperative tunnel widening after anterior cruciate ligament (ACL) reconstructions. METHODS: Inclusion criteria were patients who underwent hamstring ACL reconstructions using an adjustable-loop cortical suspension device, underwent 3D CT at the day after surgery, and were followed for a minimum of 2 years after surgery. Exclusion criteria were patients with combined ligament injury and reinjury after reconstruction. Using 3D CT, the center of the femoral tunnel aperture was located on a standardized grid system. The center of the ACL footprint was defined from the literature. The femoral tunnel location was classified as anatomic if it located within 2 standard deviations of the center position. If it was outside the 2 standard deviations, the tunnel was classified as nonanatomic. The patients were divided into either anatomic or nonanatomic groups. Femoral tunnel angles on both sagittal and coronal planes were measured. Both femoral and tibial tunnels measured on anteroposterior and lateral radiographs at immediate postoperative day and at 2 years after surgery. Postoperative knee stability and patient-reported outcomes were evaluated. RESULTS: There were 37 patients in anatomical group and 52 patients in nonanatomical group among enrolled 87 patients. There were no differences in demographics between the 2 groups. There were no differences in the femoral tunnel angles and postoperative tunnel widening between the 2 groups. A higher position correlated to the femoral tunnel widening at 2 years postoperatively. Postoperative knee stability and patient-reported outcomes showed no statistically significant differences between the 2 groups. CONCLUSIONS: There was no significant difference in postoperative tunnel widening or clinical outcomes between anatomic and nonanatomic femoral tunnel location after hamstring ACL reconstructions. A higher position correlated to the femoral tunnel widening at 2 years postoperatively. LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

Human umbilical cord blood-derived mesenchymal stem cell implantation for osteoarthritis of the knee.

INTRODUCTION: This study aimed to investigate the clinical outcomes after human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation for medial compartment (MC) osteoarthritis of the knee. MATERIALS AND METHODS: Inclusion criteria were patients older than 60 years, with a kissing lesion of the MC, a full-thickness chondral defect ≥ 4 cm2 of the medial femoral condyle (MFC), and a varus deformity ≥ 3° on a long cassette scanogram. The mean age was 64.9 ± 4.4 years and the mean chondral defect of the MFC was 7.2 ± 1.9 cm2. A mixture of sodium hyaluronate and hUCB-MSC was implanted into the chondral defect and a high tibial osteotomy was performed in all patients. International Knee Documentation Committee (IKDC), visual analog scale (VAS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were evaluated preoperatively and 1 year and 2 years postoperatively. Cartilage regeneration was evaluated in 14 (56%) patients by second-look arthroscopy at 1 year postoperatively. RESULTS: Twenty-five patients underwent hUBC-MSC implantation. IKDC, VAS, and WOMAC scores at 1 year and 2 years improved significantly compared to preoperative scores. These scores at 1 year and 2 years were not significantly different between the body mass index (BMI) < 25 group and BMI ≥ 25 group. However, the < 65-year-old group showed superior IKDC scores at 1 year and 2 years and VAS score at 2 years than the ≥ 65-year-old group. Younger age and larger size of the chondral defect were associated with a significantly greater improvement in IKDC, VAS and WOMAC scores at 2 years. Second-look arthroscopy demonstrated International Cartilage Repair Society-Cartilage Repair Assessment grade I in six (42.9%) patients and grade II in eight (57.1%). CONCLUSIONS: hUCB-MSC implantation regenerated cartilage satisfactorily and showed satisfactory clinical outcomes in patients older than 60 years who had MC osteoarthritis.

Radiologic and Clinical Outcomes After Hamstring Anterior Cruciate Ligament Reconstruction Using an Adjustable-Loop Cortical Suspension Device With Retensioning and Knot Tying.

PURPOSE: To report magnetic resonance imaging (MRI) findings and clinical outcomes after anterior cruciate ligament reconstruction using an adjustable-loop device (ALD) with retensioning and knot tying. METHODS: The inclusion criteria were patients who underwent hamstring anterior cruciate ligament reconstruction using an ALD with retensioning and knot tying between May and December 2015 and were followed up for a minimum of 2 years. The exclusion criteria were patients with combined ligament injury, revision surgery, or reinjury after reconstruction. After initial tightening of the adjustable loop, retensioning and knot tying were performed and the graft was fixed at the tibia. Multiplanar reformatted images of 3-T MRI scans were obtained on the immediate postoperative day and at 6 months after surgery to measure the gap between the top of the graft and the top of the femoral tunnel (i.e., tunnel-graft gap). Differences in the tunnel-graft gap between the immediate postoperative day and 6 months after surgery (i.e., gap difference) were calculated and correlated with knee stability and functional outcomes. RESULTS: Thirty-six patients were enrolled in this study. The mean tunnel-graft gap was 2.1 ± 2.8 mm on the immediate postoperative day and 4.6 ± 3.5 mm at 6 months after surgery (P < .001). The mean gap difference was 2.5 ± 2.0 mm. The mean KT-1000 measurement was 1.5 ± 2.2 mm, and mean Lysholm score and Tegner activity scale score were 93.6 ± 5.5 and 5.6 ± 1.5, respectively. The gap difference correlated negatively with the follow-up Lysholm score (P = .004); however, knee stability and the Tegner activity scale score were not correlated. CONCLUSIONS: Although the ALD was secured by retensioning and knot tying, MRI showed that the graft was not fully inserted in some patients and the tunnel-graft gap increased at 6 months' follow-up. The increase in the tunnel-graft gap did not correlate with knee stability or the Tegner activity scale score but correlated negatively with the Lysholm score. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Anatomic Tunnel Placement Is Not Feasible by Transclavicular-Transcoracoid Drilling Technique for Coracoclavicular Reconstruction: A Cadaveric Study.

PURPOSE: To evaluate the feasibility of anatomic tunnel placement by a transclavicular-transcoracoid drilling technique and with reference to the coracoclavicular ligaments' insertional anatomy and their orientations. METHODS: We used 12 fresh-frozen human cadaveric shoulders (6 matched pairs; mean age, 70 years; age range, 51-82 years) to simulate intraoperative tunnel placement with the transclavicular-transcoracoid drilling technique. After both the conoid and trapezoid ligaments were identified, two 2.5-mm guide pins were inserted from the clavicle to the coracoid, passing the centers of the clavicular and coracoid insertions of the conoid and the trapezoid ligaments, in a collinear fashion to the orientation of both ligaments. The entry point of the drill at the clavicle and the exit point at the coracoid undersurface, as well as the tunnel orientations, were measured. Complications due to the procedure, including a breach of the bone cortex of the clavicle and/or coracoid process, were recorded. RESULTS: The transclavicular-transcoracoid drilling technique for anatomic conoid ligament tunnel placement resulted in a medial cortical breach at the coracoid process in 6 of 12 shoulders. In the remaining 6 shoulders without a breach, the distance of the exit point from the medial cortex of the inferior coracoid process was only 3.6 ± 4.3 mm. For anatomic trapezoid ligament tunnel placement, no medial cortex breaching at the coracoid process occurred. However, the distance of the exit point was 3.1 ± 4.2 mm, indicating an eccentric location to the medial cortex of the coracoid process, similar to the conoid ligament. CONCLUSIONS: This cadaveric study showed that anatomic tunnel placement by the transclavicular-transcoracoid drilling technique would not be feasible without breaching or almost breaching the medial cortex of the coracoid process. CLINICAL RELEVANCE: The transclavicular-transcoracoid drilling technique for CC ligament reconstruction may not reproduce the anatomy of the CC ligaments but may place the coracoid process at high risk of fracture during tunnel placement.

Comparison of the insertion of the posterior horn of the lateral meniscus: discoid versus non-discoid.

PURPOSE: The purpose of this study was to compare the insertion sites of the posterior horn between discoid and non-discoid lateral meniscus using magnetic resonance imaging (MRI). METHODS: Two hundred and twenty-seven patients who had MRI scans before surgery and underwent arthroscopy were enroled in this study. A coronal view showing the narrowest width of the midbody of the lateral meniscus was chosen to measure the widths of the entire tibial plateau and the midbody of the lateral meniscus. Considering the ratio of the meniscal width to the tibial plateau width, the patients were divided into non-discoid, incomplete discoid, and complete discoid groups. On a coronal view accurately showing the insertion of the posterior horn of the lateral meniscus, a distance between the peak of the lateral tibial eminence and the centre of the insertion of the posterior horn, and a width of the lateral tibial plateau between the lateral edge of the tibial plateau and the peak of the lateral tibial eminence were measured. RESULTS: The insertion centre of the posterior horn was located more medially in the incomplete and complete discoid groups than in the non-discoid group (p = 0.003, 0.010, respectively). When individual differences in the knee size were corrected, the insertion centre of the posterior horn in the incomplete discoid and complete discoid groups was located more medially than in the non-discoid group (p = 0.009, 0.003, respectively). CONCLUSION: The insertion centre of the posterior horn of the lateral meniscus is located more medially to the apex of the lateral tibial eminence in the discoid group than in the non-discoid group. This finding needs to be considered for an accurate position of the posterior horn of lateral meniscus during the lateral meniscal allograft transplantation. LEVEL OF EVIDENCE: IV.

Loss of reduction and complications of coracoclavicular ligament reconstruction with autogenous tendon graft in acute acromioclavicular dislocations.

BACKGROUND: This study was conducted to report loss of reduction and complications after single-tunnel coracoclavicular (CC) ligament reconstruction with autogenous semitendinosus tendon graft for acute acromioclavicular (AC) joint dislocations. METHODS: This retrospective study included patients with acute, unstable AC dislocations (surgery within 6 weeks after trauma). We excluded patients with chronic injury and distal clavicle fractures with CC ligaments disruption. We measured the CC distance on anteroposterior radiographs of both clavicles, preoperatively, immediately postoperatively, and at the final follow-up visit. We evaluated clinical outcomes using the American Shoulder and Elbow Surgeons Shoulder Assessment and the University of California, Los Angeles Shoulder Rating Scale scores and perioperative complications. RESULTS: There were 30 patients (27 men and 3 women) with mean age of 41 years (range, 19-70 years). The mean follow-up period was 31 months (range, 12-186 months). Mean CC distance was 15.5 ± 3.7 mm (84% ± 14% of the contralateral shoulder) preoperatively, 8.9 ± 2.6 mm (9% ± 40%) immediately postoperatively (P < .001), and 10.6 ± 3.3 mm (24% ± 39%) at the final assessment (P < .001), showing an increase of the CC distance during the follow-up. Loss of reduction (defined as >25% increase of CC distance) developed in 14 patients (47%), and complications occurred in 6 patients (20%), including 3 distal clavicle fractures through the tunnel. Final clinical scores were significantly lower in patients with complications (27 vs. 33 of the University of California, Los Angeles assessment [P < .001] and 81 vs. 95 of the American Shoulder and Elbow Surgeons Shoulder assessment [P < .001]). CONCLUSION: In acute AC joint dislocation, single-tunnel CC ligament reconstruction using autogenous tendon graft resulted in loss of reduction rate of 47% and a complication rate of 20%. The development of complications adversely affected clinical outcomes.

The Accuracy of the Lateral Tibial Spine as a Landmark for Lateral Meniscal Allograft Transplantation.

PURPOSE: To determine a relationship between the direction of the guide pin for the keyhole in the lateral meniscus (LM) transplantation and the line connecting the centers of both horns of the LM. METHODS: Forty-four resected tibial plateaus during total knee arthroplasty were used for anatomical and radiological evaluations. The inclusion criterion was medial compartment osteoarthritis. Exclusion criteria were osteoarthritic changes, meniscal tear, and previous fracture in the lateral compartment. Resected tibial plateaus were positioned so that the anterior and posterior parts of the lateral tibial spine (LTS) were overlapped accurately on fluoroscopic anteroposterior view. A wire (Pin-F) was drilled along the peak of the LTS. The insertion area of anterior and posterior horns of the LM was dissected carefully. The periphery and the center of the insertion area of both horns were marked. Another wire (Pin-A) was drilled along a line connecting the centers of both horns. An axial radiograph was taken for each prepared tibial plateau. A longitudinal line was drawn along each wire, and the angle between the 2 wires was measured using the imaging software. If the Pin-F was externally rotated relative to the Pin-A, the angle was designated as positive, and if the Pin-F was internally rotated, the angle was designated as negative. RESULTS: The mean angle between Pin-F and Pin-A was -7.4° ± 9.6°. Thirty-three (75%) Pin-Fs were fixed in an internally rotated position, and 11 (25%) were fixed in an externally rotated position. CONCLUSIONS: The direction of most guide pins drilled along the LTS was not coincident with the line connecting the centers of both horns of the LM. CLINICAL RELEVANCE: The axis of the LTS is not a reliable marker for the trough in the LM allograft transplantation.

Suture versus FasT-Fix all-inside meniscus repair at time of anterior cruciate ligament reconstruction.

PURPOSE: To compare meniscal healing and functional outcomes after all-inside meniscal repair between sutures and meniscal fixation devices. METHODS: Sixty patients with a tear within the red-red or red-white zones of the posterior horn of the medial or lateral meniscus in conjunction with an anterior cruciate ligament (ACL) tear were included in this study. Meniscal repairs were performed with sutures in 35 patients and the FasT-Fix device (Smith & Nephew Endoscopy, Andover, MA) in 25 patients concomitantly with hamstring ACL reconstruction. Postoperative evaluations included Lysholm knee score, Tegner activity scale, Lachman and pivot-shift tests, and KT-1000 arthrometer (MEDmetric, San Diego, CA) testing. Follow-up magnetic resonance imaging (MRI) scans were obtained postoperatively for all patients to evaluate meniscal healing. RESULTS: The mean follow-up period was 47.2 months. In the suture group, 31 patients (86.1%) were asymptomatic and 4 (13.9%) were symptomatic. In the FasT-Fix group, 20 patients (80%) were asymptomatic and 5 (20%) were symptomatic. Postoperative functional evaluation and knee stability showed no statistically significant difference between the 2 groups. Follow-up MRI showed that 26 menisci (74.3%) were healed, 3 menisci (8.6%) were partially healed, and 6 menisci (17.1%) were not healed in the suture group. In the FasT-Fix group, 15 menisci (64%) were healed, 7 menisci (24%) were partially healed, and 3 menisci (12%) were not healed. Follow-up MRI showed no statistically significant difference between the 2 groups. In the FasT-Fix group, follow-up MRI showed a newly developed cyst posterior to the medial meniscus in 2 patients. A new tear anterior to the previous tear was found in 1 patient. In the suture group, follow-up MRI showed no cysts or new tears. CONCLUSIONS: All-inside meniscal repairs using either sutures or the FasT-Fix device showed satisfactory results in patients with concomitant hamstring ACL reconstruction. There was no statistically significant difference in meniscal healing evaluated by MRI and functional outcomes between the 2 techniques. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Association of Increased Lateral Femoral Condylar Ratio With Lateral Meniscus Posterior Root Tear in Noncontact ACL Injury.

Background: In the setting of anterior cruciate ligament (ACL) injury, lateral meniscus posterior root tears (LMPRTs) are less readily diagnosed on preoperative magnetic resonance imaging (MRI). Therefore, to predict LMPRTs in ACL injuries, it is necessary to understand the risk factors associated with them. Purpose/Hypothesis: The purpose of this study was to investigate the association of lateral femoral condylar ratio (LFCR) with LMPRTs in ACL injuries. It was hypothesized that an increased LFCR would be associated with LMPRTs in noncontact ACL injuries. Study Design: Cohort study; Level of evidence, 3. Methods: Enrolled were consecutive patients who underwent primary acute (<6 weeks from injury) ACL reconstruction after noncontact injury and had LMPRT confirmed on preoperative MRI and arthroscopically (combined group; n = 62) as well as patients who underwent isolated acute ACL reconstruction (isolated group; n = 80) who were matched to the combined group by age, height, and body mass index (BMI). All patients underwent surgery between January 1999 and November 2021. LFCR and posterior tibial slope (PTS) were measured and compared between the isolated and combined groups. The area under the receiver operating characteristic curve (AUC) was calculated to determine the cutoff for detecting increased risk of LMPRTs. Results: The demographic characteristics of the 2 groups did not differ significantly, nor did the PTS. The LFCR was a significant factor (odds ratio [OR], 1.23; P = .001) associated with LMPRT. Patient age, height, BMI, and PTS were not associated with LMPRT. The AUC (0.66; 95% CI, 0.57-0.75) for LFCR had a sensitivity of 39% and specificity of 90% to predict LMPRT. The calculated cutoff associated with an increased risk for LMPRT when compared with the isolated group was 67.0% (OR, 4.98; 95% CI, 2.10-11.79). Conclusion: Increased LFCR was associated with the presence of LMPRTs in patients with acute ACL injuries. The LFCR may provide surgeons with additional information regarding the risk of having a concomitant LMPRT when planning ACL reconstructions.

Bone Morphological Characteristics as Risk Factors for Anterior Cruciate Ligament Injury: Comparison Between Contact and Noncontact Injury.

Background: Altered bone morphologies are considered risk factors for noncontact anterior cruciate ligament (ACL) injuries. Purpose/Hypothesis: This study aimed to investigate bone morphological characteristics as risk factors for ACL tears in contact injuries and compare these factors with those for noncontact ACL injuries. We hypothesized that altered bone morphologies would also be risk factors for contact ACL injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Enrolled were patients who underwent primary ACL reconstructions between January 2000 and December 2021 within 6 weeks after injury. Patients in the ACL group were classified according to injury mechanism (contact vs noncontact). During the same period, a control group of patients matched by age, height, and body mass index to the ACL group was selected. The lateral femoral condylar ratio (LFCR), notch width index (NWI), and lateral posterior tibial slope (PTS) were measured. Measured parameters were compared between the control, contact, and noncontact groups using analysis of variance. Results: There were 86 patients in the control group, 102 patients in the contact ACL group, and 105 patients in the noncontact ACL group. The demographic characteristics of the 3 groups did not differ significantly. The contact group had significantly higher LFCRs and lower NWIs compared with the control group (P < .001 and P = .001, respectively). The noncontact group had significantly higher LFCRs and PTSs and lower NWIs compared with the control group (P = .031; P < .001; and P < .001, respectively). The noncontact group had significantly higher PTSs and lower NWIs compared with the contact group (P = .003 and P =.014, respectively). In the contact group, the LFCR, PTS, and NWI were significant risk factors for ACL tears (odds ratio [OR], 1.25 [P < .001]; OR, 1.16 [P = .008]; and OR, 1.27 [P = .001], respectively), and in the noncontact group, the PTS and NWI were significant risk factors for ACL tears (OR, 1.20 [P < .001]; OR, 1.59 [P < .001], respectively). Conclusion: Altered bone morphological characteristics of the knee were found to be risk factors for ACL tears in contact injuries as well as noncontact injuries. Altered morphology has a more significant effect in noncontact ACL injuries.

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.

Erratum to "Clavicular Tunnel Complications after Coracoclavicular Reconstruction in Acute Acromioclavicular Dislocation: Coracoid Loop versus Coracoid Tunnel Fixation".

[This corrects the article on p. 128 in vol. 14, PMID: 35251550.].

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.