Does the anteromedial plate position affect proximal screw length and worsen the clinical outcomes in medial opening wedge high tibial osteotomy?

BACKGROUND: During medial opening wedge high tibial osteotomy (MOWHTO), sometimes the plate tends to be positioned anteromedially. The plate position can affect the length of the proximal screw, which significantly affects stability after osteotomy. Therefore, research on the correlation among plate position, screw length, and clinical outcomes is needed. METHODS: This retrospective review examines 196 knees in 175 patients who underwent MOWHTO from May 2012 to December 2018, for symptomatic medial compartment osteoarthritis with a varus alignment of > 5°. We evaluated the anteroposterior plate position, length of proximal screw, and postoperative computed tomography (CT). We reviewed patients' clinical outcome scores, presence of lateral hinge fracture, neurovascular complications, and infection. The correlation among proximal plate position, proximal screw length, and clinical outcomes was evaluated using Pearson's correlation analysis. A subgroup analysis by screw angle (> 48 ° or < 48 °) was also performed using chi-square test and Student t-test. RESULTS: The mean proximal plate position was 16.28% (range, 5.17-44.74) of the proximal tibia's anterior-to-posterior distance ratio, and the proximal screw length averaged 63.8 mm (range, 44-80 mm). Proximal posteromedial plate position and proximal screw length were significantly correlated (r2 = 0.667, P < .001), as were screw angle and length (r2 = 0.746, P < .001). Medial plating (< 48°) can use a longer proximal screw; nevertheless, no significant difference occurred in clinical outcomes between the two groups. Also, no differences occurred in complication rate, including hinge fracture. CONCLUSION: With more medially positioned plating during MOWHTO, we can use longer proximal screws. However, there was no significant difference in clinical outcomes and the incidence of lateral hinge fractures regardless of plate position and screw length.

Single Bundle Anterior Cruciate Ligament With Anterolateral Ligament Reconstruction Yields Similar Clinical and Radiographic Results at Minimum 2-Year Follow-Up Versus Double Bundle Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Controlled Trial.

PURPOSE: To compare the clinical, radiographic, and second-look arthroscopic outcomes between double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (DB group) and combined single-bundle (SB) ACL and anterolateral ligament (ALL) reconstruction (SB + ALL group) by a prospective randomized controlled trial. METHODS: From May 2019 to June 2020, 84 patients were enrolled in this study. Among them, 10 were lost to follow-up. Thirty-six and 38 patients were successfully allocated to the DB (mean follow up 27.3 ± 4.2 months) and SB + ALL groups (27.2 ± 4.5 months), respectively. The preoperative and postoperative Lachman test, pivot shift test, anterior translation on stress radiographs, KT-2000 arthrometer, Lysholm score, International Knee Documentation Committee score, and Tegner activity score were evaluated and compared. Graft continuity was evaluated using postoperative magnetic resonance imaging (MRI) (32 and 36 patients underwent MRI in the DB and SB + ALL groups at 7.4 ± 3.2 and 7.5 ± 2.9 months after surgery, respectively), and second-look examinations (second-look examination and tibial screw removal were performed concomitantly when patients (1) had tibial screw-related irritation or (2) needed the screws removed, 28 and 23 patients underwent examinations in the DB and SB + ALL groups at 24.0 ± 6.8 and 24.9 ± 8.1 months after surgery, respectively). All measurements were compared between the groups. RESULTS: Postoperative clinical outcomes significantly improved in both groups. (All variables showed P < .001) No statistically different outcomes were found between the 2 groups. Additionally, postoperative graft continuity on MRI and second-look examinations were not different between the 2 groups. CONCLUSIONS: The DB and SB + ALL groups showed similar postoperative clinical, radiographic, and second-look arthroscopic outcomes. Both groups showed excellent postoperative stability and clinical outcomes compared with the preoperative measurements. LEVEL OF EVIDENCE: Level II, randomized controlled trial.

The Comparison of Clinical Outcomes in Elderly (≥75 Years) and Non-Elderly (<75 Years) Patients with Acute Cholangitis Due to Choledocholithiasis.

Background and Objectives: Acute cholangitis may be fatal, particularly in elderly patients. According to the Tokyo Guidelines 2018, those aged ≥75 years are classified as moderate (Grade II) severity. However, it has not been established whether age itself is the deciding factor of poor outcomes. We studied the impact of old age (≥75 years) on the mortality and morbidity of acute cholangitis due to choledocholithiasis. Materials and Methods: We retrospectively examined 260 patients with calculous acute cholangitis who had undergone biliary drainage. Patients were divided into two groups: elderly (≥75 years) and non-elderly (<75 years). We aimed to compare organ dysfunction, in-hospital mortality, intensive care unit (ICU) hospitalization, and the severity of acute cholangitis. Results: Of 260 patients, 134 (51.5%) were in the elderly group and 126 (48.5%) were in the non-elderly group. The mean age was 72.3 ± 14.4 years, and 152 (58.5%) were men. The elderly patients showed a higher incidence of shock (12.7% vs. 4.8%, p = 0.029), respiratory dysfunction (7.5% vs. 0%, p = 0.002), and renal dysfunction (8.2% vs. 0.8%, p = 0.006) than the non-elderly patients. The overall in-hospital mortality rate was 2.7%, with no significant differences between the elderly and the non-elderly (4.5% vs. 0.8%, p = 0.121). The incidence of severe acute cholangitis was significantly higher in the elderly group (26.9% vs. 9.5%, p < 0.001). However, there was no significant difference in the rates of ICU hospitalization (9.7% vs. 4%, p = 0.088) and lengths of hospital stay (LOS) (8.3 d vs. 7.1 d, p = 0.086). Conclusions: No difference was observed in the in-hospital mortality, ICU hospitalization, or LOS between the elderly (≥75 years) and the non-elderly (<75 years) with calculous acute cholangitis. However, severe acute cholangitis was significantly more frequent in elderly patients.

Anterior cruciate ligament remnant-preserving and re-tensioning reconstruction: a biomechanical comparison study of three different re-tensioning methods in a porcine model.

BACKGROUND: With the developments in the arthroscopic technique, anterior cruciate ligament (ACL) remnant-preserving reconstruction is gradually gaining attention with respect to improving proprioception and enhancing early revascularization of the graft. To evaluate the mechanical pull-out strength of three different methods for remnant-preserving and re-tensioning reconstruction during ACL reconstruction. METHODS: Twenty-seven fresh knees from mature pigs were used in this study. Each knee was dissected to isolate the femoral attachment of ACL and cut the attachment. An MTS tensile testing machine with dual-screw fixation clamp with 30° flexion angle was used. The 27 specimens were tested after applying re-tensioning sutures with No. 0 polydioxanone (PDS), using the single stitch (n = 9), loop stitch (n = 9), and triple stitch (n = 9) methods. We measured the mode of failure, defined as (1) ligament failure (longitudinal splitting of the remnant ACL) or (2) suture failure (tearing of the PDS stitch); load-to-failure strength; and stiffness for the three methods. Kruskal-Wallis test and Mann-Whitney U-test were used to compare the variance of load-to-failure strength and stiffness among the three groups. RESULTS: Ligament failure occurred in all cases in the single stitch group and in all but one case in the triple stitch group. Suture failure occurred in all cases in the loop stitch group and in one case in the triple stitch group. The load-to-failure strength was significantly higher with loop stich (91.52 ± 8.19 N) and triple stitch (111.1 ± 18.15 N) than with single stitch (43.79 ± 11.54 N) (p = 0.002). With respect to stiffness, triple stitch (2.50 ± 0.37 N/mm) yielded significantly higher stiffness than the other methods (p = 0.001). CONCLUSIONS: The results suggested that loop stitch or triple stitch would be a better option for increasing the mechanical strength when applying remnant-preserving and re-tensioning reconstruction during ACL reconstruction.

Editorial Commentary: Posterolateral Malposition of the Cortical Hinge During Medial Open-Wedge High Tibial Osteotomy Increases Posterior Tibial Slope: Incomplete Posterior Osteotomy May Shift the Hinge From Lateral to Posterolateral.

Medial open-wedge high tibial osteotomy is an established treatment option for relatively young patients with medial-compartment osteoarthritis and varus deformity. This procedure is mainly focused on correcting coronal malalignment; however, it inevitably affects the posterior tibial slope (PTS) in the sagittal plane. The alteration of the PTS significantly affects knee stability and kinematics. When medial open-wedge high tibial osteotomy is performed, incomplete osteotomy of the posterior cortex could lead to a cortical hinge shift from the lateral side to the posterolateral side, which indicates the alteration of the axial hinge axis. In this case, there is a risk of an increasing PTS. In addition, incomplete posterior cortex osteotomy can lead to a lateral hinge fracture.

Femoral Tunnel Widening After Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Autograft Produces a Small Shift of the Tunnel Position in the Anterior and Distal Direction: Computed Tomography-Based Retrospective Cohort Analysis.

PURPOSE: To determine whether the femoral tunnel position remains in an anatomical footprint after tunnel widening and shifting. METHODS: Patients who underwent unilateral double-bundle anterior cruciate ligament reconstruction with hamstring autograft and performed computed tomography scan evaluation at the time of 5 days and 1 year postoperatively were included in this retrospective cohort study. Three-dimensional models of the femur and femoral tunnels were reconstructed from computed tomography scan data. The location of the tunnel center and tunnel margins in the anatomical coordinate system, and the mean shifting distance of tunnel center and margin were measured with image analysis software during the period. The change of tunnel center location in Bernard quadrant was confirmed if the tunnel center remained within the boundaries of anatomical position after tunnel widening. RESULTS: A total of 56 patients satisfied the inclusion criteria. The mean shifting distance of AM and PL tunnel centers were 1.7 ± 0.9 mm and 1.6 ± 0.6 mm. The Tunnel margin of the anteromedial (AM) and posteromedial (PL) tunnels were shifted to 2.5 ± 1.3 mm and 2.6 ± 1.4 mm in the anterior direction, and 1.4 ± 0.9 mm and 1.0 ± 0.7 mm in the distal direction, respectively. Among the anatomical located tunnel, 97% (32/33) and 87.1% (27/31) of AM and PL tunnel centers remained in a range of anatomical footprint. The tunnel center was shifted from the anatomical position into a nonanatomical position in 3% (1/33) of the AM tunnel and 12.9% (4/31) of PL tunnel after tunnel widening. The tunnel location which shifted nonanatomically were relatively anterior and distal position. CONCLUSIONS: Tunnel widening shifts the tunnel position to the anterior and distal direction, which could change the initial tunnel position. Nevertheless, the majority of tunnel positions remained in the anatomical position after tunnel widening and shifting. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Remnant-Tensioning Single-Bundle Anterior Cruciate Ligament Reconstruction Provides Comparable Stability to and Better Graft Vascularity Than Double-Bundle Anterior Cruciate Ligament Reconstruction in Acute or Subacute Injury: A Prospective Randomized Controlled Study Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

PURPOSE: To compare the clinical, second-look arthroscopic, magnetic resonance imaging (MRI), and dynamic-contrast-enhanced MRI (DCE-MRI) findings between remnant-tensioning single-bundle (RT-SB) and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR). METHODS: Sixty-seven patients with acute or subacute anterior cruciate ligament (ACL) injury were randomized to undergo RT-SB or DB ACLR. Twenty-six patients in the RT-SB group and 28 in the DB group were evaluated using stability tests (Lachman test, pivot-shift test, and KT-2000 arthrometer) and multiple clinical scores. One year postoperatively, all 54 patients underwent MRI for evaluation of graft continuity and graft signal/noise quotient and DCE-MRI for the calculation of normalized area under the curve (nAUC) as a marker of graft vascularity. Among them, 41 patients underwent second-look arthroscopy for the evaluation of graft continuity, graft tension, and synovialization. The results were compared between the 2 groups. RESULTS: At the minimum 2-year follow-up (28.7 ± 6.4 months), the stability tests, clinical scores, second-look arthroscopic findings, and MRI findings were not significantly different between the groups. However, the mean nAUC values on DCE-MRI for the ACL graft were significantly higher in the RT-SB group than those in the DB group in all 3 zones (nAUCproximal, P = .005; nAUCmiddle, P = .021; nAUCdistal, P = .027; and nAUCaverage, P = .008). CONCLUSION: For acute or subacute ACL injury, the RT-SB ACLR showed an outcome comparable to that of DB ACLR in terms of knee stability, clinical scores, MRI findings, and second-look arthroscopic findings. Moreover, RT-SB ACLR showed better graft vascularity 1 year postoperatively than DB ACLR using DCE-MRI. LEVEL OF EVIDENCE: II, prospective randomized controlled trial.

Revision Anterior Cruciate Ligament Reconstruction After Primary Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: A Case Series of 40 Patients.

PURPOSE: To evaluate the surgical methods according to the status of tunnels at the time of revision anterior cruciate ligament reconstruction (ACLR) and to evaluate clinical outcomes of revision ACLR in patients who underwent primary ACLR with the anatomic 4-tunnel double-bundle (DB) technique. METHODS: A total of 487 patients who underwent primary anatomic DB ACLR from April 2010 to July 2016 were retrospectively reviewed, and among those knees, the patients who underwent revision ACLR were included in the study. The patients with concomitant posterior cruciate ligament injuries were excluded. Forty patients (40 knees) were identified and enrolled. The surgical methods were reviewed. The range of motion, objective laxity using KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score after revision ACLR were compared with those after primary ACLR in the same patient using paired t-test with Bonferroni correction. RESULTS: The timing of reinjury after primary ACLR and mean interval between primary and revision ACLR were 18 months (range 1.5-80 months) and 24 months (range 4-82 months), respectively. Among 40 patients, 38 patients (95%) underwent 1-stage revision with the DB technique using pre-existing tunnels without compromised positioning of the grafts, and the other 2 patients (5%) underwent 2-stage revision. The postrevision range of motion, KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score were 137 ± 7°, 2.4 ± 1.2 mm, 91.4 ± 5.8, 98.9 ± 2.2, 78.6 ± 11.5, and 5.5 ± 1.2, respectively, and did not show any differences from those after primary ACLR. CONCLUSIONS: In the revision setting after primary anatomic DB ACLR, most of the cases could be managed with 1-stage revision with DB technique using pre-existing tunnels, and the objective laxity and clinical scores after revision DB ACLR were comparable with those after primary DB ACLR. LEVEL OF EVIDENCE: Case series, Level IV.

Microfractures Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial.

PURPOSE: The purpose of this study was to evaluate the clinical efficacy and safety of treating patients with a cartilage defect of the knee with microfractures and porcine-derived collagen-augmented chondrogenesis technique (C-ACT). METHODS: One hundred participants were randomly assigned to the control group (n = 48, microfracture) or the investigational group (n = 52, C-ACT). Clinical and magnetic resonance imaging (MRI) outcomes were assessed 12 and 24 months postoperatively for efficacy and adverse events. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) assessment was used to analyze cartilage tissue repair. MRI outcomes for 50% defect filling and repaired tissue/reference cartilage (RT/RC) ratio were quantified using T2 mapping. Clinical outcomes were assessed using the visual analogue scale (VAS) for pain and 20% improvement, minimal clinically important difference (MCID), and patient acceptable symptom state for Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee score. RESULTS: MOCART scores in the investigation group showed improved defect repair and filling (P = .0201), integration with the border zone (P = .0062), and effusion (P = .0079). MRI outcomes showed that the odds ratio (OR) for ≥50% defect filling at 12 months was statistically higher in the investigation group (OR 3.984, P = .0377). Moreover, the likelihood of the RT/RC OR becoming ≥1 was significantly higher (OR 11.37, P = .0126) in the investigation group. At 24 months postoperatively, the OR for the VAS 20% improvement rate was significantly higher in the investigational group (OR 2.808, P = .047). Twenty-three patients (52.3%) in the control group and 35 (77.8%) in the investigation group demonstrated more than the MCID of KOOS pain from baseline to 1 year postoperatively, with a significant difference between groups (P = .0116). CONCLUSION: In this multicenter randomized trial, the addition of C-ACT resulted in better filling of cartilage defect of the knee joint. LEVEL OF EVIDENCE: Level Ⅰ, Multicenter Randomized Controlled Trial.

Difference in joint line convergence angle between the supine and standing positions is the most important predictive factor of coronal correction error after medial opening wedge high tibial osteotomy.

PURPOSE: Coronal correction errors after medial opening wedge high tibial osteotomy (MOWHTO) occasionally occur even with the assistance of navigation. The purpose of the present study was to determine the navigation accuracy in MOWHTO and to identify factors that affect the coronal correction error after navigation-assisted MOWHTO. METHODS: A total of 114 knees treated with navigation-assisted MOWHTO were reviewed retrospectively. Mechanical axis (MA) on standing radiograph and medial proximal tibial angle (MPTA) were measured preoperatively and at 6 months postoperatively, and the differences (ΔMA and ΔMPTA) were calculated. Joint line convergence angle (JLCA) on supine and standing radiographs was measured preoperatively, and their difference (ΔJLCA) was calculated. To assess the navigation accuracy, ΔMA and ΔMPTA were compared with the coronal correction by navigation (ΔNMA) using intraclass correlation coefficients (ICCs). Univariable and multivariable regression analyses were used to identify factors that affect coronal correction discrepancy (ΔMA - ΔNMA). RESULTS: The reliability of navigation was good in terms of bony correction (ICC between ΔNMA and ΔMPTA, 0.844) and fair in terms of MA correction (ICC between ΔNMA and ΔMA, 0.706). The mean coronal correction discrepancy was 2.0° ± 2.4°. In the multivariable analysis, ΔJLCA was shown to be a predictive factor of coronal correction discrepancy (unstandardized coefficient, 1.026; R2, 0.470). CONCLUSION: Navigation in MOWHTO provided reliable information about bony correction; however, MA tended to be overcorrected. The difference in JLCA between the supine and standing radiographs was the most important preoperative factor that predicted the coronal correction discrepancy after MOWHTO. In patients with larger ΔJLCA, each degree of ΔJLCA should be subtracted from the planned amount of correction angle when preoperative planning is performed using standing radiographs. LEVEL OF EVIDENCE: IV.

Partial meniscectomy does not affect the biomechanics of anterior cruciate ligament reconstructed knee with a lateral posterior meniscal root tear.

PURPOSE: The purpose of this study was to determine the effects of a lateral meniscus posterior root tear, partial meniscectomy, and total meniscectomy on knee biomechanics in the setting of anterior cruciate ligament (ACL) reconstruction. METHODS: Thirteen fresh-frozen cadaver knees were tested with a robotic testing system under an 89.0-N anterior tibial load at full extension (FE), 15°, 30°, 60° and 90° of knee flexion and a simulated pivot-shift loading (7.0 Nm valgus and 5.0 Nm internal tibial rotation) at FE, 15° and 30° of knee flexion. Anterior tibial translation (ATT) and the in-situ force of ACL graft under the different loadings were measured in four knee states: (1) ACL reconstruction with intact lateral meniscus (Intact meniscus), (2) ACL reconstruction with lateral meniscal posterior root tear (Root tear), (3) ACL reconstruction with lateral posterior partial meniscectomy (Partial meniscectomy) and (4) ACL reconstruction with total lateral meniscectomy (Total meniscectomy). RESULTS: Under anterior tibial loading, compared with an intact meniscus, root tear significantly increased ATT at 15° and 30° of knee flexion (p < 0.05) and partial meniscectomy had almost same increased ATT as with root tear at any knee flexion between FE and 90°. Under simulated pivot-shift loading, total meniscectomy increased ATT compared with intact meniscus, root tear, partial meniscectomy at FE (p < 0.05). CONCLUSION: Under anterior tibial and simulated pivot-shift loading, partial meniscectomy has no significant effect on the stability of ACL-reconstructed knee with lateral meniscal posterior root tear, while total meniscectomy increased laxity at less than 30° of knee flexion. Clinically, in cases of irreparable meniscal root tears or persistent pain a partial meniscectomy can be considered in the setting of ACL reconstruction.

Preoperative latent medial laxity and correction angle are crucial factors for overcorrection in medial open-wedge high tibial osteotomy.

PURPOSE: This study aimed to determine which preoperative factors affect the postoperative change in the joint line convergence angle (JLCA) by preoperatively quantifying soft tissue laxity. METHODS: Thirty-four patients who underwent medial open-wedge high tibial osteotomy (HTO) with a navigation were analysed. The JLCA change after HTO was calculated using standing long-bone anteroposterior radiographs taken preoperatively and 6 months postoperatively. Latent soft tissue laxity was defined as the amount of soft tissue that can be extended to valgus or varus from the weight-bearing position, and calculated by subtracting the JLCA on weight-bearing standing radiographs from that on stress radiographs. Multiple linear regression was performed to determine the preoperative factors that statistically correlated with the postoperative JLCA change. RESULTS: In multiple linear regression, JLCA change had a statistically significant correlation with latent medial laxity (R = 0.6) and a statistically borderline significant correlation with correction angle (R = 0.2). These imply that the postoperative JLCA change increased by 0.6° per 1° increase in latent medial laxity, and increased by 0.2° per 1° increase in correction angle. Latent medial laxity was the most crucial factor associated with postoperative JLCA changes. CONCLUSION: The JLCA change could be larger in patients with large latent medial laxity or severe varus deformity requiring a large correction, which could lead to unexpected overcorrection in HTO. Postoperative JLCA change should be considered in preoperative surgical planning. Target point shifting within the hypomochlion point could be a strategy to prevent overcorrection, especially in patients with large latent medial laxity. LEVEL OF EVIDENCE: Level IV.

Predictive Factors for Patellofemoral Degenerative Progression After Opening-Wedge High Tibial Osteotomy.

PURPOSE: To identify risk factors for patellofemoral degenerative progression after opening-wedge high tibial osteotomy (HTO) and to investigate the effect of patellofemoral degeneration on the patellofemoral specific patient-reported outcomes. METHODS: Between March 2010 and June 2016, 94 knees (86 patients) underwent hardware removal with second-look arthroscopy at 21.4 months after opening-wedge HTO with first-look arthroscopy (mean follow-up duration, 49.8 months). Predictive factors for patellofemoral degeneration, including demographics, preoperative and postoperative mechanical axis (MA) of the lower limb (positive and negative MA indicating varus and valgus, respectively), tibial slope, and modified Blackburne-Peel ratio, were evaluated. Patients were divided into the progression and nonprogression groups according to their patellofemoral degenerative progression from first to second arthroscopy. Clinical outcomes, including the Kujala score and Knee Injury and Osteoarthritis Outcome Score, and radiographic outcomes were compared between the 2 groups. RESULTS: Postoperative MA (adjusted odd ratio, 0.62; P < .001) was the most significant predictive factor for progressive change in the patellofemoral joint (Rn2 = 0.31). Twenty-eight knees (30%) showed patellofemoral degenerative progression. Mean postoperative Kujala score (progression group 60.5 vs nonprogression group, 72.3; P = .005) and Knee Injury and Osteoarthritis Outcome Score scales (except for the symptom subscale) were lower in the progression group. Postoperative MA was significantly more corrected in the progression group (progression group -5.1° ± 2.7° vs nonprogression group -2.4° ± 2.3°; P < .001). CONCLUSIONS: Postoperative MA, which might be related to overcorrection, is correlated with patellofemoral degenerative progression after opening-wedge HTO. Patients with patellofemoral degenerative progression showed inferior patient-reported outcomes. LEVEL OF EVIDENCE: Level IV, case series with subgroup analysis.

A Comparative Biomechanical Study of Femoral Cortical Suspension Devices for Soft-Tissue Anterior Cruciate Ligament Reconstruction: Adjustable-Length Loop Versus Fixed-Length Loop.

PURPOSE: To determine whether there are differences between adjustable-length loop and fixed-length loop devices in terms of the amount of displacement, temporal pattern of displacement, and ultimate failure load when tested using 4,500 cycles of sinusoidal loading with high loads (100-400 N). METHODS: Two cortical suspension devices with a fixed- or adjustable-length loop were tested. For our comparisons, a 20-mm fixed-length loop device and a fixed-length loop device with the same loop length were used. Comparisons between the devices used both a device-only model (DOM) and a device-bone-soft-tissue graft construct model (CM). RESULTS: In the DOM, the adjustable-length loop device showed weaker mechanical properties. Mean cumulative peak displacement was 1.91 mm for the adjustable-length loop device and 0.74 mm for the fixed-length loop device (P = .001). The displacement of the adjustable-length loop device increased between 1,000 and 4,500 cycles; in contrast, that of the fixed-length loop device reached a plateau. However, there was never displacement greater than 3 mm. In addition, the adjustable-length loop device showed a weaker ultimate failure load (925 N vs 1,410 N, P = .001). In the CM, the difference in cumulative peak displacement between the 2 groups decreased and did not reach statistical significance. The displacement of both devices showed a similar pattern. In addition, there was no difference in ultimate failure load between the 2 groups. CONCLUSIONS: There was no significant difference in terms of total displacement, temporal pattern of displacement, and ultimate failure load between the 2 devices in the CM, which is the more clinically relevant model. Furthermore, even in the DOM, the difference in total displacement was small and did not reach a clinically meaningful level. Therefore, both devices can be used effectively during anterior cruciate ligament reconstruction with soft-tissue graft. CLINICAL RELEVANCE: Both femoral cortical suspension devices with adjustable- and fixed-length loops can be used with similar mechanical properties during anterior cruciate ligament reconstruction.

Comparison of Tibiofemoral Contact Mechanics After Various Transtibial and All-Inside Fixation Techniques for Medial Meniscus Posterior Root Radial Tears in a Porcine Model.

PURPOSE: To compare tibiofemoral contact mechanics after fixation for medial meniscus posterior root radial tears (MMPRTs). METHODS: Seven fresh knees from mature pigs were used. Each knee was tested under 5 conditions: normal knee, MMPRT, pullout fixation with simple sutures, fixation with modified Mason-Allen sutures, and all-inside fixation using Fastfix 360. The peak contact pressure and contact surface area were evaluated using a capacitive sensor positioned between the meniscus and tibial plateau, under a 1,000-N compression force, at different flexion angles (0°, 30°, 60°, and 90°). RESULTS: The peak contact pressure was significantly higher in MMPRTs than in normal knees (P = .018). Although the peak contact pressure decreased significantly after fixation at all flexion angles (P = .031), it never recovered to the values noted in the normal meniscus. No difference was observed among fixation groups (P = .054). The contact surface area was significantly lower in MMPRTs than in the normal meniscus (P = .018) and increased significantly after fixation at all flexion angles (P = .018) but did not recover to within normal limits. For all flexion angles except 60°, the contact surface area was significantly higher for fixation with Mason-Allen sutures than for fixation with simple sutures or all-inside fixation (P = .027). At 90° of flexion, the contact surface area was significantly better for fixation with simple sutures than for all-inside fixation (P = .031). CONCLUSIONS: The peak contact pressure and contact surface area improved significantly after fixation, regardless of the fixation method, but did not recover to the levels noted in the normal meniscus after any type of fixation. Among the fixation methods evaluated in this time 0 study, fixation using modified Mason-Allen sutures provided a superior contact surface area compared with that noted after fixation using simple sutures or all-inside fixation, except at 60° of flexion. However, this study had insufficient power to accurately detect the differences between the outcomes of various fixation methods. CLINICAL RELEVANCE: Our results in a porcine model suggest that fixation can restore tibiofemoral contact mechanics in MMPRT and that fixation with a locking mechanism leads to superior biomechanical properties.

Three-Dimensional Bio-Printed Scaffold Sleeves With Mesenchymal Stem Cells for Enhancement of Tendon-to-Bone Healing in Anterior Cruciate Ligament Reconstruction Using Soft-Tissue Tendon Graft.

PURPOSE: To investigate the efficacy of the insertion of 3-dimensional (3D) bio-printed scaffold sleeves seeded with mesenchymal stem cells (MSCs) to enhance osteointegration between the tendon and tunnel bone in anterior cruciate ligament (ACL) reconstruction in a rabbit model. METHODS: Scaffold sleeves were fabricated by 3D bio-printing. Before ACL reconstruction, MSCs were seeded into the scaffold sleeves. ACL reconstruction with hamstring tendon was performed on both legs of 15 adult rabbits (aged 12 weeks). We implanted 15 bone tunnels with scaffold sleeves with MSCs and implanted another 15 bone tunnels with scaffold sleeves without MSCs before passing the graft. The specimens were harvested at 4, 8, and 12 weeks. H&E staining, immunohistochemical staining of type II collagen, and micro-computed tomography of the tunnel cross-sectional area were evaluated. Histologic assessment was conducted with a histologic scoring system. RESULTS: In the histologic assessment, a smooth bone-to-tendon transition through broad fibrocartilage formation was identified in the treatment group, and the interface zone showed abundant type II collagen production on immunohistochemical staining. Bone-tendon healing histologic scores were significantly higher in the treatment group than in the control group at all time points. Micro-computed tomography at 12 weeks showed smaller tibial (control, 9.4 ± 0.9 mm2; treatment, 5.8 ± 2.9 mm2; P = .044) and femoral (control, 9.6 ± 2.9 mm2; treatment, 6.0 ± 1.0 mm2; P = .03) bone-tunnel areas in the treated group than in the control group. CONCLUSIONS: The 3D bio-printed scaffold sleeve with MSCs exhibited excellent results in osteointegration enhancement between the tendon and tunnel bone in ACL reconstruction in a rabbit model. CLINICAL RELEVANCE: If secure biological healing between the tendon graft and tunnel bone can be induced in the early postoperative period, earlier, more successful rehabilitation may be facilitated. Three-dimensional bio-printed scaffold sleeves with MSCs have the potential to accelerate bone-tendon healing in ACL reconstruction.

The clinical and radiological results of individualized surgical treatment depending on pathologic abnormalities in recurrent patellar dislocation: low recurrence rate, but unintended patella baja.

PURPOSE: To evaluate the clinical and radiological outcomes and chondral lesion change using individualized surgery for recurrent patellar dislocation. METHODS: A total of 31 knees with recurrent patellar dislocation underwent surgery depending on individual pathologic abnormalities. Pathologic abnormalities including medial laxity, lateral tightness, increased tibial tuberosity (TT)-to-trochlear groove distance (>20 mm), and patella alta (Caton-Deschamps ratio >1.2) were evaluated in each patient. The abnormalities were corrected through medial patellofemoral ligament reconstruction, TT distalization, TT anteromedialization, and lateral retinacula release. The mean follow-up period was 33 months. RESULTS: There was one recurrent case (3.2%), requiring additional surgery. The mean Kujala scores were significantly (P = 0.002) improved from 75.8 (SD 12.4) to 84.6 (SD 13.1). Tegner scores were significantly improved from 3.7 (range 1-9) to 5.4 (range 2-9) (P < 0.001), as were and visual analogue scale pain scores from 4.7 (SD 2.5) to 2.6 (SD 2.2) (P = 0.001). Caton-Deschamps ratio was significantly decreased from 1.1 (SD 0.2) to 0.9 (SD 0.1) (P < 0.001), regardless of TT distalization. Chondral lesions of the patella and trochlear groove were improved or maintained in 57.1 and 71.4% of patients, respectively. CONCLUSION: Individualized surgery in recurrent patellar dislocation was effective and safe with a low recurrence rate. However, the possibility of unintended patella baja, which might be related to post-operative anterior knee pain, should be considered. LEVEL OF EVIDENCE: IV.

Steeper posterior tibial slope correlates with greater tibial tunnel widening after anterior cruciate ligament reconstruction.

PURPOSE: To investigate the correlation between posterior tibial slope (PTS) and tibial tunnel widening after anterior cruciate ligament reconstruction (ACL-R). METHODS: Twenty-five patients underwent anatomic single-bundle ACL-R using quadriceps tendon autograft. Six months after surgery, each patient underwent high-resolution computed tomography (CT). Tibial tunnel aperture location was evaluated using a grid method. Medial and lateral PTS (°) was measured based on a previously described method. To evaluate tibial tunnel widening, cross-sectional area (CSA) of the tibial tunnel beneath the aperture was measured using CT axial slice. Nominal elliptical area was calculated using the diameter of a dilator during the surgery and the angle between the axial slice and the tunnel axis. Percentage of tunnel widening (%) was determined by dividing the CSA by the nominal area. Pearson correlation coefficient was used to explore the association between medial/lateral PTS and tibial tunnel widening (P < 0.05). RESULTS: Location of tibial tunnel aperture was 29.8 ± 6.3% in anterior-posterior direction, and 45.7 ± 2.1% in medial-lateral direction. Medial and lateral PTS were 3.7° ± 2.5° and 4.9° ± 2.4° respectively. Tibial tunnel widening was 97.2 ± 20.3%. Tibial tunnel widening was correlated with medial PTS (r = 0.558, P = 0.004) and lateral PTS (r = 0.431, P = 0.031). CONCLUSION: Steeper medial and lateral PTS correlated with greater tibial tunnel widening. The clinical relevance is that surgeons should be aware that PTS may affect tibial tunnel widening after ACL-R. Thus, subjects with steeper PTS may need to be more carefully followed to see if there is greater tibial tunnel widening, which might be important especially in revision ACL-R. LEVEL OF EVIDENCE: III.

Diagnosis of Internal Derangement of the Knee: Volume Isotropic Turbo Spin-Echo Acquisition MRI With Fat Suppression Versus Without Fat Suppression.

OBJECTIVE: The purpose of this study was to compare 3D volume isotropic turbo spin-echo acquisition (VISTA) MRI with and without fat suppression for use in evaluating ligaments, menisci, and cartilage. MATERIALS AND METHODS: Two radiologists retrospectively and independently reviewed 71 MRI studies. Each study consisted of 3D intermediate-weighted VISTA images with fat suppression and without fat suppression. The presence of tears of the anterior cruciate and posterior cruciate ligaments, tears of the medial and lateral menisci, and cartilaginous defects was evaluated. Arthroscopic surgical findings were used as the standard of reference. Statistical analysis was performed to calculate the sensitivity, specificity, and accuracy of the two methods. RESULTS: Mean specificity and accuracy for medial meniscal tears were significantly higher with VISTA (specificity, 95.0%; accuracy, 94.4%) than with fat-suppressed VISTA (FS-VISTA) (specificity, 81.3%; accuracy, 85.9%), and the difference was statistically significant (specificity, p = 0.003; accuracy, p = 0.004). Mean specificity for cartilaginous defects was also significantly higher with VISTA than with FS-VISTA (99.1% vs 96.8%, p = 0.039). There were no other significant differences between the two methods. CONCLUSION: Three-dimensional VISTA MRI has higher specificity than FS-VISTA imaging for evaluation of medial meniscal tears and cartilaginous defects.

Paradoxical tunnel enlargement after ACL reconstruction with hamstring autografts when using ß-TCP containing interference screws for tibial aperture fixation- prospectively comparative study.

BACKGROUND: Tibial aperture fixation with a bioabsorbable interference screw is a popular fixation method in anterior cruciate ligament reconstruction (ACLR). An interference screw containing ß-tricalcium phosphate (ß-TCP) to improve bony integration and biocompatibility was recently introduced. This study aims to compare the clinical outcomes and radiological results of tunnel enlargement effect between the 2 bioabsorbable fixative devices of pure poly-L-lactic acid (PLLA) interference screws and ß-TCP-containing screws, for tibial interference fixation in ACLR using hamstring autografts. METHODS: Eighty consecutive patients who had undergone double-bundle ACLR between 2011 to 2012 were prospectively reviewed and randomly divided into two groups based on the type of tibial interference screw: 28 were assigned to the pure PLLA screw group (Group A), while the other 29 were assigned to the ß-TCP-containing screw fixation group (Group B). Clinical evaluations and radiological analyses were conducted in both groups with a minimum 2- year follow-up. RESULTS: There was no significant difference in subjective or objective clinical outcome between the 2 groups. In radiological analyses, the use of a ß-TCP-containing screw reduced tunnel widening in the portion of the tunnel with screw engagement compared to the pure PLLA screw, while the use of a ß-TCP-containing screw resulted in greater tunnel enlargement in the proximal portion of the tunnel without screw engagement than use of a pure PLLA screw. CONCLUSION: Use of a ß-TCP-containing interference screw in tibial aperture fixation reduced tunnel enlargement in the vicinity of the screw, whereas greater enlargement occurred proximal to the screw end relative to use of a pure PLLA interference screw. These paradoxical enlargements in use of ß-TCP containing screws suggest that for reducing tunnel enlargement, the length of the interference screw should be as fit as possible with tunnel length in terms of using soft grafts. LEVEL OF EVIDENCE: II, Prospectively comparative study. TRIAL REGISTRATION: Retrospectively registered with ClinicalTrials.gov. (NCT02754674) , Date of trial registration: February 10, 2016.