The position of the femoral insertion has a great influence on the laxity of the knee joint after ACLR, especially for rotational laxity.
To compare the effects of different femoral tunnel positions on knee stability after arthroscopic anterior cruciate ligament reconstruction (ACLR).
The clinical outcomes of 165 patients after autograft ACLR were analyzed retrospectively. The patients were separated into three groups according to the position of the femoral tunnel, as follows: low center (LC) group, 53 patients; high center (HC) group, 45 patients; and high anteromedial (HAM) group, 67 patients. The side-to-side differences (SSDs) in anteroposterior knee laxity measured using a KT-2000 arthrometer and the pivot shift test (PST) pre- and postoperatively were compared among the three groups and analyzed.
After 5 years postoperatively, the SSD in the anteroposterior knee laxity in the three groups was significantly decreased postoperatively compared with preoperatively in knees; meanwhile, the negative PST rate was significantly increased in the three groups. The postoperative SSD in anteroposterior knee laxity was significantly increased in the HC group compared with the LC and HAM groups (1.5 ± 1.3 VS 1.0 ± 1.1 VS 1.0 ± 1.0, P<0.05). The negative postoperative PST rate was higher in both the LC and HAM groups than in the HC group (84.9% VS 91.0% VS 71.1%, P<0.05), and there was no significant difference in the negative PST rate between the LC and HAM groups (84.9% VS 91.0%, P>0.05). The negative postoperative PST rate was significantly higher in the HAM group than in the LC and HC groups for patients with a high degree of laxity preoperatively (31.3% VS 3.3% VS 14.4%, P>0.05).
Patients in HAM group showed better control over anteroposterior laxity, rotational laxity, and subjective knee function compared to other groups post operation. Therefore, the HAM point is the closest to the I.D.E.A.L point concept, and is recommended as the preferred location for the femoral tunnel in ACLR.

OBJECTIVE: To describe the technique of primary repair of medial collateral ligament (MCL) insufficiency using a screw and rectangular spiked washer in a case series of 14 patients.
METHODS: Fourteen patients undergoing MCL repair by a screw and rectangular spiked washer during TKA between March 2018 and March 2019 were retrospectively reviewed. Among them, half injuries were avulsion of the femoral origin, and the other half were MCL laxity. There were 12 women and two men included in the study, with an average age of 63.6 years (range, 49-79 years) at the time of surgery. This series were followed up with a focus on range of motion (ROM), coronal alignment, Hospital for Special Surgery (HSS) knee scores, their subjective sense of joint instability, and related complications. At the last follow-up, function of the MCL was assessed by manually applying a valgus stress to the knee at both 0° and 30° of knee flexion.
RESULTS: The mean follow-up time for all patients was 15.6 months (range, 13-20 months). Repair of the MCL was successful in all patients. ROM improved from a mean of 70.7° ± 35.1° before surgery to 103.9° ± 6.8° at latest follow-up (P = 0.001). All patients were able to perform a half squat easily, but none were able to do full squatting. The mean preoperative HSS score was 43.6 ± 13.4 and increased to a mean of 85.6 ± 3.8 postoperatively (P < 0.001). The femorotibial angle improved from a mean of -3.22° ± 9.47° before surgery to a mean of 5.16° ± 3.14° at the final follow-up (P = 0.006). At the time of final follow-up, no patient required revision and manipulation under anesthesia following the index arthroplasty. No radiolucencies or migration were observed in association with the knee prostheses. No displacement of the screw and rectangular spiked washer was found. There were no clinical complications. No patient reported subjective instability of the knee. Upon physical examination, no patient was found to have laxity in the coronal plane in either 30° of flexion or full extension.
CONCLUSIONS: The screw and rectangular spiked washer is a simple and effective method for treating MCL sufficiency in TKA, and a study with a larger cohort and extended follow-up is requisite to claim its role in preventing coronal instability and component failure.

BACKGROUND: Biomechanical measurement tools have been developed and widely used to precisely quantify knee anterior-posterior laxity after anterior cruciate ligament (ACL) injury. However, validated objective device to document knee rotational laxity, though being developed by different researchers, are not yet widely used in the daily clinical practice. A new biomechanical device was developed to quantify knee internal and external rotations.
METHODS: The reliability of the new biomechanical device which measures knee rotations were tested. Different torques (1-10Nm) were applied by the device to internally and externally rotate human cadaveric knees, which were held in a flexion angle of 30°. The rotations were measured by the device in degrees. There were two independent testers, and each tester carried out three trials. Intra-rater and inter-rater reliability were quantified in terms of intraclass correlation (ICC) coefficient among trials and between testers. The device was verified by the comparison with a computer assisted navigation system. ICC was measured. Mean, standard deviation and 95% confident interval of the difference as well as the root mean square difference were calculated. The correlations were deemed to be reliable if the ICC was above 0.75.
RESULTS: The intra-rater and inter-rater reliability achieved high correlation for both internal and external rotation, ranged from 0.959 to 0.992. ICC between the proposed meter and the navigation system for both internal and external rotation was 0.78. The mean differences were 2.3° and 2.5° for internal and external rotation respectively.
CONCLUSIONS: A new knee rotational laxity meter was proposed in this study. Its reliability was verified by showing high correlation among trials. It also showed good correlation to a gold standard of measurement. It might be used to document knee rotational laxity for various purposes, especially after ACL injury, after further validation of the device in human subjects.

OBJECTIVE: Treatment of posterolateral corner (PLC) injury in the multiligament-injured knee is still controversial. The aim of this study was to investigate the clinical outcome of acute or sub-acute surgical repair of Type 1 and 2 PLC peel-off lesions in a multiligament setting.
METHODS: Mini-open direct repair of the PLC was performed in 13 patients. Combined PCL, ACL and MCL injuries were simultaneously managed. Telos valgus and varus stress radiographs at 30° of flexion with 150 N load were used to investigate medial and lateral joint opening. Posterior stress radiograph with 150 N load was used to investigate the function of the PCL. External rotational laxity was assessed with a dial test at 30° of knee flexion, and photographs were taken to measure angles. Anterior displacement was examined using the manual maximum test performed with a KT-1000 arthrometer.
RESULTS: A statistically significant reduction between pre- and postoperative laxity values was achieved for every test. Particularly, lateral joint opening side-to-side difference reduced from 10.3 ± 4.0 to 1.0 ± 3.2 mm and external rotation reduced from 15 ± 8° to 0° ± 6° more than that of the contralateral uninjured knee. The medial joint opening side-to-side difference reduced from 11.5 ± 5.6 to 2.6 ± 2.7 mm in the 7 patients surgically managed for MCL lesion. The anterior tibial displacement side-to-side difference reduced from 14.0 ± 5.0 to 3.0 ± 5.0 mm in the 9 patients surgically managed for ACL lesion. The posterior tibial translation side-to-side difference reduced from 11.1 ± 5.1 to 4.4 ± 3.9 mm in the 11 patients treated for PCL lesion.
CONCLUSIONS: The main finding of the current study is that acute repair of Type 1 and 2 PLC peel-off injury proved to be an effective procedure to restore PLC function in a multiligament-injured knee. These data enabled the current literature with an effective treatment option to face such a complex and various scenarios such as multiligament-injured knee.
METHODS: IV.

OBJECTIVE: Radiofrequency (RF) shrinkage is used in anterior cruciate ligament (ACL) reconstruction. The present study investigated the therapeutic effects of RF on ACL relaxation and the probable influencing factors.
METHODS: Patients with ACL relaxation were included. Participants were randomly divided into two groups: a treatment group, in which patients were treated with RF shrinkage (RF group); a control group, in which patients received conventional surgical treatment. Thermal shrinkage was performed on ACL using an ArthroCare® CAPSure® wand. Lysholm scores, proprioceptive testing and Tegner activity scores were evaluated before and after treatment (at 6 and 12 months).
RESULTS: A total of 38 patients were included. The mean ± SD Lysholm score of those in the RF group at 12 months\' post-treatment was significantly higher than in controls. The angle of deviation of the knee joint in RF group was significantly larger than in the control group at 6 months\' post-treatment.
CONCLUSIONS: RF shrinkage treatment for ACL laxity could improve knee scores, and may affect proprioception and recovery of activity after surgery.