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Background: The pivot-shift test has become more consistent and reliable and is a meaningful outcome measurement after anterior cruciate ligament reconstruction (ACLR)., Purpose/hypothesis: The purpose of this investigation was to assess patient-reported outcomes (PROs) and the quantitative pivot shift (QPS) preoperatively, at time zero immediately after anatomic ACLR, and after 24 months as well as the relationship between PROs and the QPS. It was hypothesized that anatomic ACLR would restore rotatory stability measured by the pivot-shift test and that QPS measurements would be positively correlated with PROs., Study Design: Cohort study; Level of evidence, 2., Methods: The ACL-injured and contralateral uninjured knees from 89 of 107 (83.2%) enrolled patients at 4 international centers were evaluated using a standardized pivot-shift test. Tibial acceleration was assessed with an inertial sensor, and lateral compartment translation was measured using an image analysis system preoperatively, at time zero immediately postoperatively, and at follow-up after 2 years. PROs were assessed at 12 and 24 months postoperatively with the International Knee Documentation Committee (IKDC) subjective knee form, Cincinnati Knee Rating System (CKRS), Marx activity rating scale, and activity of daily living score (ADLS)., Results: The mean patient age at surgery was 27 years (range, 15-45 years). A positive pivot shift preoperatively (side-to-side difference in tibial acceleration, 2.6 ± 4.0 m/s 2 ; side-to-side difference in anterior tibial translation, 2.0 ± 2.0 mm) was reduced at time zero postoperatively (side-to-side difference in tibial acceleration, -0.5 ± 1.3 m/s 2 ; side-to-side difference in anterior tibial translation, -0.1 ± 1.0 mm). All PROs improved from preoperatively to final follow-up at 24 months: from 56.5 to 85.5 points for the IKDC ( P = .0001), from 28.8 to 32.4 points for the CKRS ( P = .04), from 11.2 to 7.9 points for the Marx ( P < .0001), and from 75.7 to 91.6 points for the ADLS ( P < .0001). Neither preoperative nor time zero postoperative rotatory laxity assessed by the pivot-shift test correlated with PROs at 24-month follow-up. A graft retear was observed in 4 patients (4.5%) within 2 years of follow-up., Conclusion: Anatomic ACLR resulted in significantly improved and acceptable PROs at 2-year follow-up and a low failure rate. Anatomic ACLR restored QPS measurements of anterior tibial translation and tibial acceleration to those of the contralateral knee immediately after surgery while still under anesthesia, but there was no correlation between the QPS preoperatively or at time zero after ACLR and PROs at 2-year follow-up., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study was funded by an International Society for Arthoscopy, Knee Surgery and Orthopedic Sports Medicine/Orthopedic Research and Eduction Foundation research grant (No. 708661). J.J.I., Y.H., and V.M. are codevelopers of the image analysis system used in this study; at the moment, the system is not on the market and not producing revenue. R.K. has received grants from Smith & Nephew, Zimmer Biomet, Stryker, and Johnson & Johnson; consulting fees from Medacta, Arthrex, Japan Tissue Engineering, and Hirosaki Life Science Innovation; and speaking fees from Arthrex, Smith & Nephew, Zimmer Biomet, Johnson & Johnson, and Japan Tissue Engineering. V.M. has received consulting fees and speaking fees from Smith & Nephew. A.S. has received grant support from Arthrex and Stryker; educational support from Arthrex, Mid-Atlantic Surgical Systems, and Smith & Nephew; and hospitality payments from Stryker. J.M.B. has received grant support from Arthrex and educational support from Arthrex, Smith & Nephew, and Mid-Atlantic Surgical Systems. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Background: It is still uncertain how surgical reconstruction of the anterior cruciate ligament (ACL) is able to restore rotatory laxity of the involved joint. The desired amount of restraint applied by the ACL graft, as compared with the healthy knee, has not been fully clarified., Purpose: To quantify the ability of single-bundle anatomic ACL reconstruction using hamstring tendons in reducing the pivot-shift phenomenon immediately after surgery under anesthesia., Study Design: Case series; Level of evidence, 4., Methods: An inertial sensor and image analysis were used at 4 international centers to measure tibial acceleration and lateral compartment translation of the knee, respectively. The standardized pivot-shift test was quantified in terms of the side-to-side difference in laxity both preoperatively and postoperatively with the patient under anesthesia. The reduction in both tibial acceleration and lateral compartment translation after surgery and the side-to-side difference were evaluated using the Wilcoxon signed-rank test. Alpha was set at P < .05., Results: A total of 107 patients were recruited for the study, and data were available for 89 patients. There was a statistically significant reduction in quantitative rotatory knee laxity between preoperatively (inertial sensor, 2.55 ± 4.00 m/s 2 ; image analysis, 2.04 ± 2.02 mm) and postoperatively (inertial sensor, -0.54 ± 1.25 m/s 2 ; image analysis, -0.10 ± 1.04 mm) between the involved and healthy joints, as measured by the 2 devices ( P < .001 for both). Postoperatively, both devices detected a lower rotatory laxity value in the involved joint compared with the healthy joint (inertial sensor, 2.45 ± 0.89 vs 2.99 ± 1.10 m/s 2 , respectively [ P < .001]; image analysis, 0.99 ± 0.83 vs 1.09 ± 0.92 mm, respectively [ P = .38])., Conclusion: The data from this study indicated a significant reduction in the pivot shift when compared side to side. Both the inertial sensor and image analysis used for the quantitative assessment of the pivot-shift test could successfully detect restoration of the pivot shift after anatomic single-bundle ACL reconstruction. Future research will examine how pivot-shift control is maintained over time and correlation of the pivot shift with return to full activity in patients with an ACL injury., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This work was supported by a grant from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine and the Orthopaedic Research and Education Foundation (grant No. 708661). S.Z. is a consultant for Smith & Nephew and DePuy. V.M. is a consultant for Smith & Nephew, has grants/grants pending from Mid-Atlantic Surgical, and receives educational support from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Purpose: The objective of the present study was to correlate macroscopic and microscopic anatomy of the lateral capsule of the knee joint with high-quality magnetic resonance imaging (MRI), with a hypothesis that a distinct lateral capsular ligament would be inconsistently observed via surgical dissection and that high-quality MRI imaging would correlate to findings from dissection., Methods: Ten fresh-frozen human cadaveric knee specimens were utilized for this study. MRI of each knee was obtained pre- and post-dissection. The lateral knee was dissected and analysed for the presence or absence of a discrete capsular thickening or an independent ligamentous structure. A musculoskeletal radiologist analysed the pre- and post-dissection MRI. Subsequently, two specimens with positive lateral capsular thickening were prepared for histology., Results: On macroscopic dissection, none of the ten specimens were found to have a discrete lateral capsular ligament. A palpable macroscopic thickening of the lateral capsule was identified in 4/10 specimens. MRI analysis revealed a 2-4 mm thickening of the central third of the lateral capsule in 3/10 specimens. On histological analysis, the lateral capsular thickening demonstrated properties similar to both capsule and ligament., Conclusions: In fresh-frozen cadaveric specimens, macroscopic and MRI evaluation of the lateral capsule of the knee revealed variations in morphology without consistent capsuloligamentous anatomy and specifically no discrete lateral capsular ligament. Further investigation in the form of clinical and mechanical relevance of the lateral capsular structures is of paramount importance before limited anatomical data can be utilized to drive clinical decision-making and patient care.

Objective: To ascertain the coronal angles for the femoral and tibial tunnels that provide the best postoperative result from anterior cruciate ligament (ACL) reconstruction surgery, through assessing the variables of the IKDC and Lysholm-Tegner questionnaires and the hop test., Methods: Sixteen patients with a single unilateral ACL injury who underwent this surgery between 24 and 36 months earlier were evaluated. They were divided into four groups in which the tibial and femoral tunnel angles were greater than or less than 65° in the coronal plane., Results: The results demonstrated that a more vertical angle for the tibial tunnel (72°) and a more horizontal angle for the femoral tunnel (60°), with valgus alignment of 12° correlated with the best values for the variables studied. This may indicate that the long-term results from this surgery are excellent., Conclusion: A more horizontal femoral angle and a more vertical tibial angle produced better assessments in the tests that were applied and in the functional results evaluated.

Unlabelled: The pivot shift test is the only physical examination test capable of predicting knee function and osteoarthritis development after an ACL injury. However, because interpretation and performance of the pivot shift are subjective in nature, the validity of the pivot shift is criticized for not providing objective information for a complete surgical planning for the treatment of rotatory knee laxity. The aim of ACL reconstruction was eliminating the pivot shift sign. Many structures and anatomical characteristics can influence the grading of the pivot shift test and are involved in the genesis and magnitude of rotatory instability after an ACL injury. The objective quantification of the pivot shift may be able to categorize knee laxity and provide adequate information on which structures are affected besides the ACL. A new algorithm for rotational instability treatment is presented, accounting for patients' unique anatomical characteristics and objective measurement of the pivot shift sign allowing for an individualized surgical treatment., Level of Evidence: V.