Comprehensive evaluation of magnetic resonance imaging sequences for signal intensity based assessment of anterior cruciate ligament healing following surgical treatment.

Normalized signal intensity (SI) obtained from magnetic resonance imaging (MRI) has been used to track anterior cruciate ligament (ACL) postoperative remodeling. We aimed to assess the effect of MRI sequence (PD: proton density-weighted; T2: T2-weighted; CISS: constructive interference in steady state) on postoperative changes in healing ACLs/grafts. We hypothesized that CISS is better at detecting longitudinal SI and texture changes of the healing ACL/graft compared to the common clinical sequences (PD and T2). MR images of patients who underwent ACL surgery were evaluated and separated into groups based on surgical procedure (Bridge-Enhanced ACL Repair (BEAR; n = 50) versus ACL reconstruction (ACLR; n = 24)). CISS images showed decreasing SI across all timepoints in both the BEAR and ACLR groups (p < 0.01), PD and T2 images showed decreasing SI in the 6-to-12- and 12-to-24-month postoperative timeframes in the BEAR group (p < 0.02), and PD images additionally showed decreasing SI between 6- and 24-months postoperation in the ACLR group (p = 0.02). CISS images showed texture changes in both the BEAR and ACLR groups, showing increases in energy and decreases in entropy in the 6-to-12- and 6-to-24-month postoperative timeframes in the BEAR group (p < $\lt $ 0.04), and increases in energy, decreases in entropy, and increases in homogeneity between 6 and 24 months postoperation in the ACLR group (p < 0.04). PD images showed increases in energy and decreases in entropy between 6- and 24-months postoperation in the ACLR group (p < 0.008). Finally, CISS was estimated to require a smaller sample size than PD and T2 to detect SI differences related to postoperative remodeling.

Instrument-based anterolateral rotatory laxity assessment of the knee has a high intra-observer and inter-observer reliability: a systematic review.

IMPORTANCE: A reliable evaluation of anterolateral rotatory instability in the anterior cruciate ligament (ACL) deficient knee is important to help surgeons determine which patients might need concurrent anterolateral augmentation procedures. OBJECTIVE: The purpose of this study was to systematically review studies that assess the intra-observer and inter-observer reliability of instruments used to measure anterolateral rotatory laxity of the knee. EVIDENCE REVIEW: A comprehensive literature review was conducted according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, using PubMed, Embase, Scopus, and Google Scholar databases for original, English-language studies evaluating the reliability of objective or instrument-based anterolateral rotatory laxity of the knee until October 31, 2022. Reliability data were extracted from text, tables, and figures. FINDINGS: Twelve studies, with patients between the ages of 14-63 years, were included. The instruments used to measure anterolateral rotatory knee laxity included inertial sensors (n â€‹= â€‹9), magnetic resonance imaging (n â€‹= â€‹1), and navigation systems (n â€‹= â€‹2). The global intra-observer intraclass correlation coefficient for these devices was between 0.63 and 0.97, and the global inter-observer reliability was between 0.63 and 0.99. CONCLUSION AND RELEVANCE: Instrument-based anterolateral rotatory knee laxity assessment has moderate to good intra- and inter-observer reliability. Evaluating anterolateral instability in ACL-deficient knees with these devices could help in decision-making when considering anterolateral augmentation. LEVEL OF EVIDENCE: IV.

A modified triple tibial osteotomy for management of canine cranial cruciate ligament disease: retrospective assessment of 309 procedures (2017-2020).

CASE HISTORY: Medical records from a single referral hospital (Animal Referral Hospital, Sinnamon Park, Australia) of dogs treated with modified triple tibial osteotomy (TTO) for management of cranial cruciate ligament (CrCL) disease from June 2017 to June 2020 were reviewed. Modifications to the originally described TTO procedure included a modified wedge angle calculation and performing the tibial osteotomies without the use of pre-drilled guide holes. CLINICAL FINDINGS: A total of 253 dogs met the inclusion criteria. Two dogs were excluded, leaving 251 dogs that had undergone 309 procedures for assessment, and data from these, including complications, were reviewed. Complete, partial competent, and partial incompetent rupture of the cranial cruciate ligament was identified in 202/309 (65.4%), 79/309 (25.6%), and 28/309 (9.1%) stifles, respectively. Medial meniscal injury was identified in 207/309 (67.0%) stifles at the time of initial surgery. TREATMENT AND OUTCOME: Fifty-eight dogs had bilateral procedures, including both single-session and staged surgeries, and 48 of these were available for analyses. The modifications to the TTO procedure described herein resulted in a median wedge angle of 21° and a median post-operative tibial plateau angle of 5.8°. Tibial compression testing following surgery indicated elimination of cranial tibial thrust in all stifles in this series. The most common intra-operative complication was tibial tuberosity fracture (15/309; 4.9%). Minor post-operative complications occurred in 37/309 (12.0%) procedures, with infection being the most common (27/309; 8.7%). Major post-operative complications occurred in 9/309 (2.9%) procedures. The intra- and post-operative complication rates for dogs undergoing bilateral single-session TTO were both 8.3% (2/24). The intra- and post-operative complication rates for dogs undergoing bilateral staged TTO were both 4.2% (1/24). The low number of complications for both the bilateral single-session and bilateral staged TTO groups precluded statistical analysis. All complications resolved uneventfully as determined by the attending surgeon. CLINICAL RELEVANCE: The modified TTO technique described here was safe and effective for the management of canine CrCL disease in the dogs included in the case series. Findings of this study suggest that, with careful case selection, the modified TTO may be performed as a bilateral single-session procedure in dogs with concurrent bilateral cranial cruciate ligament disease. Future studies analysing the effects of these modifications on stifle biomechanics would be beneficial. ABBREVIATIONS: CrCL: Cranial cruciate ligament; SSI: Surgical site infection; TPA: Tibial plateau angle; TPLO: Tibial plateau levelling osteotomy; TTA: Tibial tuberosity advancement; TTO: Triple tibial osteotomy.

Instantaneous center of rotation in the canine femorotibial joint: Ex vivo assessment of a tool to evaluate joint stabilization surgeries.

Cranial cruciate ligament rupture is a common cause of femorotibial joint instability in the dog. Numerous techniques including several tibial osteotomies have been described for stabilization, but there is no current consensus on the best method. The instantaneous center of rotation (ICR) can aid investigations of pathological joint movement, but its use is problematic in the femorotibial joint due to combined rotation and translation during flexion and extension. Using fluoroscopic images from an earlier cadaveric study of canine joint stability, an interpolation method was used to create repeatable rotational steps across joint situations, followed by least squares approximation of the ICR. The ICR in intact joints was located mid-condyle but displaced significantly (P < 0.001) proximally following cranial cruciate ligament transection and medial meniscal release. Individual joints appear to respond differently to destabilization. Triple tibial osteotomy partially restored ICR location during early movement from flexion to extension. Joint instability significantly altered the proportions of rolling and gliding movement at the joint surface (P < 0.02), which triple tibial osteotomy partially improved. While triple tibial osteotomy restores joint stability ex vivo and clinically, normal biomechanics of the joint are not restored. The methods described here may prove useful for comparison of osteotomy techniques for stabilization of the cranial cruciate ligament deficient femorotibial joint in dogs.

3D assessment of graft malposition after ACL reconstruction: Comparison of native and 11o'clock ligament orientations.

BACKGROUND: Femoral tunnel malposition makes up the majority of technical failures for ACL reconstructive surgery. The goal of this study was to develop adolescent knee models that accurately predict anterior tibial translation when undergoing a Lachman and pivot shift test with the ACL in the 11o'clock femoral malposition (Level of Evidence: IV). METHODS: FEBio was used to build 22 subject-specific tibiofemoral joint finite element representations. To simulate the two clinical tests, the models were subject to loading and boundary conditions established in the literature. Clinical, historical control data were used to validate the predicted anterior tibial translations. RESULTS: A 95% confidence interval showed that with the ACL in the 11o'clock malposition, the simulated Lachman and pivot shift tests produced anterior tibial translations that were not statistically different from the in vivo data. The 11o'clock finite element knee models resulted in greater anterior displacement than those with the native (approximately 10o'clock) ACL position. The difference in anterior tibial translation between the native and 11o'clock ACL orientations was statistically significant. CONCLUSION: Clinically, by understanding the impact that ACL orientation has in anterior tibial displacement biomechanics, surgical interventions can be improved to prevent technical errors from occurring. The integration of this methodology into surgical practice not only allows for anatomical visualization prior to surgery, but also creates the opportunity to optimize graft placement, thus improving post-surgical outcomes.

Diagnostic value of DECT-based colored collagen maps for the assessment of cruciate ligaments in patients with acute trauma.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of third-generation dual-source dual-energy CT (DECT) color-coded collagen reconstructions for the assessment of the cruciate ligaments compared to standard grayscale image reconstruction. METHODS: Patients who underwent third-generation dual-source DECT followed by either 3-T MRI or arthroscopy of the knee joint within 14 days between January 2016 and December 2021 were included in this retrospective study. Five radiologists independently evaluated conventional grayscale DECT for the presence of injury to the cruciate ligaments; after 4 weeks, readers re-evaluated the examinations using grayscale images and color-coded collagen reconstructions. A reference standard for MRI was provided by a consensus reading of two experienced readers and arthroscopy. Sensitivity and specificity were the primary metrics of diagnostic performance. RESULTS: Eighty-five patients (mean age, 44 years ± 16; 50 male) with injury to the ACL or PCL (n = 31) were ultimately included. Color-coded collagen reconstructions significantly increased overall sensitivity (94/105 [90%] vs. 67/105 [64%]), specificity (248/320 [78%] vs. 215/320 [67%]), PPV (94/166 [57%] vs. 67/162 [39%]), NPV (248/259 [96%] vs. 215/253 [85%]), and accuracy (342/425 [81%] vs. 282/425 [66%]) for the detection of injury to the anterior cruciate ligament (all parameters, p < .001). For injury to the posterior cruciate ligament, diagnostic accuracy increased for complete tears (p < .001). Color-coded collagen reconstructions achieved superior diagnostic confidence, image quality, and noise scores compared to grayscale CT (all parameters, p < .001) and showed good agreement with MRI examinations. CONCLUSIONS: DECT-derived color-coded collagen reconstructions yield substantially higher diagnostic accuracy and confidence for assessing the integrity of the cruciate ligaments compared to standard grayscale CT in patients with acute trauma. KEY POINTS: • Color-coded collagen reconstructions derived from dual-energy CT yield substantially higher diagnostic accuracy and confidence for the assessment of the cruciate ligaments compared to standard grayscale CT in patients with acute trauma. • Color-coded collagen reconstructions demonstrate good agreement with MRI for the assessment cruciate ligament injury. • Dual-energy CT may serve as a readily available screening approach for patients with acute trauma to the knee when injury to the cruciate ligaments is suspected.

Outcome and owner assessment after single-session bilateral tibial plateau leveling osteotomy in 127 dogs.

Objective: To retrospectively evaluate complication rates following bilateral tibial plateau leveling osteotomy (TPLO) as well as owner assessment of outcomes and post-operative management. Methods: Medical records of dogs presenting with bilateral cranial cruciate ligament (CCL) disease that underwent single-session bilateral TPLO from 2015 to 2019 in 1 referral practice were retrospectively reviewed. A non-validated questionnaire was sent to the owners to assess their ability to cope during the rehabilitation period, as well as procedure outcome. Results: In total, 127 dogs were included for analysis. The overall complication rate was 16.5% (minor complication rate 9.4% and major complication rate 10.2%). Of the 50 owners that answered the questionnaire, 31 (62%) did not need to use sling support at home at any time and 10 (20%) used sling support for < 1 wk. Furthermore, only 1 owner indicated that they would not choose to do a bilateral TPLO surgery again. Clinical significance: Bilateral single-session TPLO surgery performed by an experienced surgeon had a similar outcome and complication rate to that of unilateral TPLO surgery. Most owners reported that postoperative care of their dog was not difficult.

Résultats et évaluation par le propriétaire après une ostéotomie bilatérale de nivellement du plateau tibial e n une seule séance chez 127 chiens. Objectif: Évaluer rétrospectivement les taux de complications après une ostéotomie bilatérale de nivellement du plateau tibial (TPLO) ainsi que l'évaluation par le propriétaire des résultats et de la prise en charge postopératoire. Méthodes: Les dossiers médicaux des chiens présentant une pathologie bilatérale du ligament croisé crânien (CCL) ayant subi une TPLO bilatérale en une seule séance de 2015 à 2019 dans une pratique de référence ont été examinés rétrospectivement. Un questionnaire non validé a été envoyé aux propriétaires pour évaluer leur capacité à faire face pendant la période de réhabilitation, ainsi que le résultat de la procédure. Résultats: Au total, 127 chiens ont été inclus pour l'analyse. Le taux global de complications était de 16,5 % (taux de complications mineures 9,4 % et taux de complications majeures 10,2 %). Sur les 50 propriétaires qui ont répondu au questionnaire, 31 (62 %) n'ont pas eu besoin d'utiliser une écharpe à domicile à tout moment et 10 (20 %) ont utilisé une écharpe pendant < 1 semaine. De plus, un seul propriétaire a indiqué qu'il ne choisirait pas de refaire une chirurgie bilatérale TPLO. Signification clinique: La chirurgie TPLO bilatérale en une seule séance réalisée par un chirurgien expérimenté a eu un résultat et un taux de complications similaires à ceux de la chirurgie TPLO unilatérale. La plupart des propriétaires ont déclaré que les soins postopératoires de leur chien n'étaient pas difficiles.(Traduit par Dr Serge Messier).

Loaded open-kinetic-chain exercises stretch the anterior cruciate ligament more than closed-kinetic-chain exercises: In-vivo assessment of anterior cruciate ligament length change.

BACKGROUND: Usage of open-kinetic-chain (OKC) or closed-kinetic-chain (CKC) exercises during rehabilitation planning after anterior cruciate ligament (ACL) reconstruction has been debated for decades. However, the ACL elongation pattern during different rehabilitation exercises at different loadings remains unclear. OBJECTIVES: This study aimed to determine the effects of OKC and CKC exercises on the length of ACL anteromedial bundle (AMB) and posterolateral bundle (PLB) to provide biomechanical support for making rehabilitation schedules. DESIGN: Laboratory Descriptive Study. METHOD: Eighteen healthy volunteers were asked to perform two OKC motions, including non-weight-bearing and 10 kg loaded seated knee extension (OKC-0, OKC-10), as well as two CKC motions, including box squat (BS) and deep single-legged lunge (Lunge). Techniques of 2D-to-3D image registration and 3D ligament simulation were used to quantify length changes of ACL. RESULTS: The motion which led to the least and most ACL elongation were OKC-0 and OKC-10, respectively. The AMB and PLB were significantly longer in OKC-10 than those in OKC-0 during 0-60° and 0-55° of knee flexion (p < 0.01). Compared with reference length, the AMB and PLB were stretched during 0-30° and 0-10° respectively during OKC-10. During CKC exercises, the AMB and PLB were also stretched from 0 to 25°and 0-5°, respectively. Additionally, no significant difference was found in the length change of ACL bundles between BS and lunge. CONCLUSIONS: OKC-0 may be safe for the rehabilitation program after ACL reconstruction, and loaded exercises shall be applied when restricted with >30° in early-stage rehabilitation.

Después de una cirugía de ligamento cruzado anterior, ¿cuándo puedo manejar? Evaluación postoperatoria de habilidades de conducción y de reacción de frenado / After anterior cruciate ligament surgery, when can I drive? Postoperative assessment of driving skills and braking reaction

Introducción: La mayoría de las personas que se someten a una reconstrucción del LCA están en edad de conducir, por lo tanto, es importante saber cuándo es seguro para el paciente reanudar la conducción. El objetivo de este trabajo es evaluar de manera prospectiva cuándo los pacientes recuperan las habilidades de manejo y de reacción de frenado después de la reconstrucción primaria de LCA, y compararlos con un grupo control de voluntarios sanos. Materiales y métodos: estudio prospectivo de una serie de pacientes que se sometieron a reconstrucción primaria del LCA utilizando injerto semitendinoso y recto interno. Se excluyeron pacientes en los que se empleó otro tipo de injerto o se les realizó otro gesto quirúrgico y laborales. Se evaluó la capacidad de volver a manejar de manera segura a las 2-3 semanas y a las 4-5 semanas postoperatorias mediante test de reacción simple y de resistencia a la monotonía, y se compararon los resultados con un grupo control de voluntarios sanos. Resultados: en total fueron ciento sesenta y seis pacientes, treinta fueron casos y ciento treinta y seis, controles. Se hallaron diferencias significativas (p = 0.03) entre los casos y controles en las pruebas realizadas tempranamente en cuanto a la aprobación, y no, de los test. Según el promedio en segundos obtenido en cada test realizado, se observan diferencias significativas en el primera prueba de resistencia a la monotonía (p = 0.0001) a favor del grupo control. Discusión: de acuerdo a la prueba de reacción simple y al test a la monotonía evaluados en nuestro trabajo, los pacientes que se someten a reconstrucción del LCA con autoinjertos de ST-RI están en condiciones de manejar un automóvil luego de las 4-5 semanas de la cirugía

Introduction: Most people who undergo ACL reconstruction are of driving age, it is important to know when it is safe for the patient to resume driving. The objective of this work was to prospectively evaluate when patients recover driving skills and brake reaction skills after ACL reconstruction and compare them with a control group of healthy volunteers. Materials and methods: prospective study of a series of patients who underwent primary ACL reconstruction using semitendinosus and medial rectus graft. Patients in whom another type of graft was used, or another surgical and labor gesture was performed, were excluded. The ability to return to driving safely at 2-3 weeks and 4-5 weeks postoperatively was evaluated using the simple reaction and resistance to monotony tests, and the results were compared with a control group of healthy volunteers.Results: a total of 166 patients, 30 are cases and 136 controls. Significant differences (p = 0.03) were found between cases and controls in the tests carried out early in terms of passing and not passing the tests. The relationship according to the average in seconds obtained in each test carried out, significant differences are observed in the first test of resistance to monotony (p = 0.0001) in favor of the control group. Discussion: according to the simple reaction test and the monotony test evaluated in our study, patients who undergo ACL reconstruction with ST-RI autografts are able to drive a car 4-5 weeks after surgery

Assessment of Ligament Viscoelastic Properties Using Raman Spectroscopy.

Injuries to the ligaments of the knee commonly impact vulnerable and physically active individuals. These injuries can lead to the development of degenerative diseases such as post-traumatic osteoarthritis (PTOA). Non-invasive optical modalities, such as infrared and Raman spectroscopy, provide means for quantitative evaluation of knee joint tissues and have been proposed as potential quantitative diagnostic tools for arthroscopy. In this study, we evaluate Raman spectroscopy as a viable tool for estimating functional properties of collateral ligaments. Artificial trauma was induced by anterior cruciate ligament transection (ACLT) in the left or right knee joint of skeletally mature New Zealand rabbits. The corresponding contralateral (CL) samples were extracted from healthy unoperated joints along with a separate group of control (CNTRL) animals. The rabbits were sacrificed at 8 weeks after ACLT. The ligaments were then harvested and measured using Raman spectroscopy. A uniaxial tensile stress-relaxation testing protocol was adopted for determining several biomechanical properties of the samples. Partial least squares (PLS) regression models were then employed to correlate the spectral data with the biomechanical properties. Results show that the capacity of Raman spectroscopy for estimating the biomechanical properties of the ligament samples varies depending on the target property, with prediction error ranging from 15.78% for tissue cross-sectional area to 30.39% for stiffness. The hysteresis under cyclic loading at 2 Hz (RMSE = 6.22%, Normalized RMSE = 22.24%) can be accurately estimated from the Raman data which describes the viscous damping properties of the tissue. We conclude that Raman spectroscopy has the potential for non-destructively estimating ligament biomechanical properties in health and disease, thus enhancing the diagnostic value of optical arthroscopic evaluations of ligament integrity.

Bone plug fixation in anterior cruciate ligament reconstruction: A clinical and radiological assessment of graft-tunnel integration.

BACKGROUND: The decision regarding graft choice and fixation in anterior cruciate ligament (ACL) reconstruction remains controversial. Free cylindrical bone plugs have been used successfully as graft fixation method. However, some concerns continue to exist regarding how well these plugs integrate with the bony walls of the tunnel. The aim of this study was to assess osteo-integration of free cylindrical bone plugs and to evaluate its effect on the clinical outcomes of the procedure. METHODS: From January 2015 to December 2017, 30 patients (21-40 years old) with torn ACL were operated on and followed up for 24 months after surgery. All patients were assessed clinically (International Knee Documentation Committee score (IKDC) and Tegner-Lysholm knee scoring system), instrumentally (KT 1000 and Rolimeter), and radiologically (X-ray, computed tomography and magnetic resonance imaging). Young active patients with torn ACL were included while those with previous ligamentous injury and/or surgery were excluded. RESULTS: All bone grafts showed solid bone healing after 6 months of surgery; incorporation was 'good to excellent' (tibial side: 66.6%; femoral side: 86.6%). There was no correlation between age or time interval and graft incorporation. Positive correlation was shown between tibial and femoral graft incorporation within the same patient. Only one patient was abnormal in our final objective IKDC scores (graded C). The mean side-to-side difference with KT 1000 and Rolimeter was 1.9 and 1.8, respectively. CONCLUSION: Free cylindrical bone plugs could be used safely for hamstring tendon graft fixation; it enhances graft tunnel integration within the first 6 months and yields comparable clinical outcomes whilst avoiding the potential hazards of foreign hardware implants.

Varus stress MRI in the refined assessment of the posterolateral corner of the knee joint.

Magnetic resonance imaging (MRI) is commonly used to assess traumatic and non-traumatic conditions of the knee. Due to its complex and variable anatomy, the posterolateral corner (PLC)-often referred to as the joint's dark side-remains diagnostically challenging. We aimed to render the diagnostic evaluation of the PLC more functional by combining MRI, varus loading, and image post-processing in a model of graded PLC injury that used sequential transections of the lateral collateral ligament, popliteus tendon, popliteofibular ligament, and anterior cruciate ligament. Ten human cadaveric knee joint specimens underwent imaging in each condition as above, and both unloaded and loaded using an MR-compatible device that standardized loading (of 147 N) and position (at 30° flexion). Following manual segmentation, 3D joint models were used to computationally measure lateral joint space opening for each specimen, configuration, and condition, while manual measurements provided the reference standard. With more extensive ligament deficiency and loading, lateral joint spaces increased significantly. In conclusion, varus stress MRI allows comprehensive PLC evaluation concerning structural integrity and associated functional capacity. Beyond providing normative values of lateral compartment opening, this study has potential implications for diagnostic and surgical decision-making and treatment monitoring in PLC injuries.

Morphometric assessment of the medial collateral ligament of the canine stifle joint.

OBJECTIVE: The study provides a morphometric assessment of the medial collateral ligament (MCL) of the canine stifle joint. STUDY DESIGN: Eighty-six stifle joints were collected from 43 canine cadavers and dissected to free them of soft tissue and expose the collateral ligaments. The MCL insertion sites were identified with Chinese ink on intact stifle joints and also marked with radiopaque paste after removal of the MCL. Mediolateral photographs and radiographs of each stifle joint were taken after MCL was removed for morphometric assessment. Measurements were taken in two groups: a group of Beagles (group 1), and a group composed of different breeds (group 2). RESULTS: In all stifle joints, the MCL had an hourglass shape. It inserted in the distal femur and the proximal tibia, and was also intimately attached to the medial meniscus and more loosely to the proximal tibial epiphysis in its central portion. The MCL tibial insertion (TI) site had the largest surface area. Its proximal and distal position relative to the tibial plateau was located at 8.24 ± 1.17% and 15.54 ± 1.50% respectively of the total tibial length in group 1, and at 8.86 ± 1.93% and 15.53 ± 2.11% respectively, of the total tibial length in group 2. These values were not statistically different. CONCLUSION: The MCL of the canine stifle joint has an insertion site on the femur and on the tibia and is also attached on the medial meniscus. The location of the MCL TI site seems to be relatively homogeneous in dogs.

Conservative nonsurgical treatment for cranial cruciate ligament disease can be an effective management strategy in cats based on validated owner-based subjective assessment in some cases.

OBJECTIVE: To describe long-term outcomes of cats managed medically for cranial cruciate ligament disease (CCLD) via a validated owner-based questionnaire. ANIMALS: 18 client-owned cats. PROCEDURES: Retrospective review of medical records at 2 tertiary referral hospitals was conducted for records of cats diagnosed with CCLD for which medical management was pursued. History, physical examination findings, and medical management strategies were recorded. Owner follow-up was obtained via phone call or an email correspondence interview using a 2-part questionnaire. Part 1 consisted of 5 multiple-choice questions evaluating short-term outcomes following initiation of medical management. Part 2 assessed long-term outcomes via the validated Feline Musculoskeletal Pain Index-short form metrology instrument. RESULTS: Mean follow-up time was 66.5 ± 46.7 months (range, 7 to 154 months). Medical management included oral analgesics, activity restriction, and joint supplements. Of the 18 cats, 13 (72%) were always able to bear weight or became weight bearing within a week following initiation of medical management, and 15 (83%) were reportedly clinically normal within 3 months of initiating medical management, with complete resolution of lameness occurring in less than 2 months in 12 of those cats. Long term, 17 of the 18 (94%) owners reported they felt that their cat had a good to excellent outcome with medical management. The mean Feline Musculoskeletal Pain Index-short form score of all cats was 0.29 ± 0.53 (range, 0 to 2.13). CLINICAL RELEVANCE: Based on owner follow-up, conservative, nonsurgical management of CCLD can be an effective and appropriate management strategy for some cats; however, some may be best treated with surgical stabilization.

Ligamentization of the reconstructed ACL differs between the intraarticular and intraosseous regions: A quantitative assessment using UTE-T2* mapping.

BACKGROUND: The purpose of this study was to prospectively observe the trends of ultrashort echo time (UTE)-T2* values for the intraarticular and intraosseous regions of reconstructed anterior cruciate ligaments from 6 to 12 months after anterior cruciate ligament reconstruction by using UTE-T2* mapping, and to investigate the changes and differences over time in each region. METHODS: Ten patients underwent UTE-T2* mapping of the operated knee at 6, 9, and 12 months after anterior cruciate ligament reconstruction. The UTE-T2* values of intraarticular and intraosseous regions of reconstructed anterior cruciate ligaments at 6, 9, and 12 months postoperatively were statistically compared. RESULTS: The UTE-T2* values of the intraarticular region at 6 months postoperatively were significantly higher than those at 9 and 12 months. There were no significant differences in the UTE-T2* values at 6, 9, and 12 months postoperatively in the intraosseous region. At 6 months postoperatively, the UTE-T2* values of the intraarticular region were significantly higher than those of the intraosseous region. The UTE-T2* values of the intraosseous region at the tibia were significantly lower than those of the other sites at any postoperative time point. CONCLUSIONS: According to UTE-T2*mapping-based findings, histological maturation of reconstructed ACLs is faster in the intraosseous region than in the intraarticular region. In particular, the intraarticular region is still undergoing rapid histologic changes at 6 months postoperatively, and its tissue structure is less substantial than normal. The findings of this study may provide clues to determine the optimal timing for safe return to sports in terms of ligamentaization of reconstructed ACLs.

Anterior cruciate ligament foot plate anatomy: 3-dimensional and 2-dimensional MRI evaluation with arthroscopy assessment in a subset of patients.

OBJECTIVES: ACL reconstruction tunnel location is an important predictor for outcomes after surgery. The aim was to establish 3D and 2D MRI radiological measurements for native ACL tibial footprint that can provide information to facilitate pre-operative planning for anatomical graft placement. The measurements were also correlated in a subset of patients on arthroscopy. METHODS: Retrospective evaluation of a consecutive series of knee MRIs with both 2D and 3D MR imaging was performed in 101 patients with 43 men and 66 women and ages 39.5 ± 11.9 years. Two measurements were obtained, tibial to ACL and intermeniscal ligament to ACL (T-ACL) and (IM-ACL), respectively. In a cohort of 18 patients who underwent knee arthroscopy, the T-ACL and IML-ACL distances were also determined by an orthopedic surgeon using a standard scale. ICC, Pearson correlation, and Bland-Altman plot were generated. RESULTS: For readers 1 and 2, the mean differences between 2D and 3D measurements of T-ACL and IM-ACL were 1.17 and 1.03 mm and 0.65 and 0.65 mm, respectively. The 2D measurements of T-ACL and IM-ACL were larger than the 3D measurements for both readers. The inter-reader reliability was excellent on 2D (0.81-0.96) and fair to excellent on 3D MRI (0.59-0.90). The mean arthroscopic IML-ACL was closer to that of 3D MRI compared to 2D MRI. The mean arthroscopic T-ACL was closer to 2D MRI than 3D MRI. CONCLUSIONS: Both 2D and 3D MRI show inter-reader reliability with small inter-modality mean differences in the measurements from the tibial or inter-meniscal ligament margins. KEY POINTS: • The mean differences between 2D and 3D measurements of tibia-ACL and intermeniscal ligament-ACL are small (< 1.2 mm). • As compared to arthroscopy, the mean T-ACL and IML-ACL were closer to measurements from 2D and 3D MRI, respectively. • Both 2D and 3D MRI can be reliably used to delineate ACL foot plate anatomy.

Automatic segmentation model of intercondylar fossa based on deep learning: a novel and effective assessment method for the notch volume.

BACKGROUND: Notch volume is associated with anterior cruciate ligament (ACL) injury. Manual tracking of intercondylar notch on MR images is time-consuming and laborious. Deep learning has become a powerful tool for processing medical images. This study aims to develop an MRI segmentation model of intercondylar fossa based on deep learning to automatically measure notch volume, and explore its correlation with ACL injury. METHODS: The MRI data of 363 subjects (311 males and 52 females) with ACL injuries incurred during non-contact sports and 232 subjects (147 males and 85 females) with intact ACL were retrospectively analyzed. Each layer of intercondylar fossa was manually traced by radiologists on axial MR images. Notch volume was then calculated. We constructed an automatic segmentation system based on the architecture of Res-UNet for intercondylar fossa and used dice similarity coefficient (DSC) to compare the performance of segmentation systems by different networks. Unpaired t-test was performed to determine differences in notch volume between ACL-injured and intact groups, and between males and females. RESULTS: The DSCs of intercondylar fossa based on different networks were all more than 0.90, and Res-UNet showed the best performance. The notch volume was significantly lower in the ACL-injured group than in the control group (6.12 ± 1.34 cm3 vs. 6.95 ± 1.75 cm3, P < 0.001). Females had lower notch volume than males (5.41 ± 1.30 cm3 vs. 6.76 ± 1.51 cm3, P < 0.001). Males and females who had ACL injuries had smaller notch than those with intact ACL (p < 0.001 and p < 0.005). Men had larger notches than women, regardless of the ACL injuries (p < 0.001). CONCLUSION: Using a deep neural network to segment intercondylar fossa automatically provides a technical support for the clinical prediction and prevention of ACL injury and re-injury after surgery.

Use of Blumensaat's line for assessment of cranial tibial subluxation in dogs with cranial cruciate ligament deficiency.

BACKGROUND: This study aimed to determine whether Blumensaat's line, a consistently present radiographic feature delineating the peak of the femoral intercondylar fossa, could be used to assess for cranial tibial subluxation in canine stifles with cranial cruciate ligament disease. METHODS: Thirty sequential, neutrally positioned, standing-angle stifle radiographs were taken from dogs presenting to a specialist referral centre for treatment of cruciate ligament disease. Thirty similarly positioned radiographs of healthy canine stifles were used as a control group. The radiographs were anonymised and submitted to blinded observers for measurement of the tibial plateau angle, patella tendon angle, Blumensaat's line length and the length of Blumensaat's line cranial to the tibial mechanical axis. RESULTS: Finding that the tibial mechanical axis intersects Blumensaat's line cranial to its midpoint, as a marker of cranial tibial subluxation, had a positive predictive value of 76% for subsequent surgical identification of cruciate ligament disease. CONCLUSIONS: Tibial cranial subluxation is detectable and quantifiable radiographically using the intersection of the tibial mechanical axis and Blumensaat's line. Once quantified, this measurement could be used both as a radiographic marker of cruciate ligament disease and to adjust tibial osteotomy procedures to minimise the risk of under advancement of the tibial tuberosity resulting in a persistently unstable stifle.