Multiclass Support Vector Machine improves the Pivot-shift grading from Gerdy's acceleration resultant prior to the acute Anterior Cruciate Ligament surgery.

INTRODUCTION: Rotatory laxity acceleration still lacks objective classification due to interval grading superposition, resulting in a biased pivot shift grading prior to the Anterior Cruciate Ligament (ACL) reconstruction. However, data analysis might help improve data grading in the operative room. Therefore, we described the improvement of the pivot-shift categorization in Gerdy's acceleration under anesthesia prior to ACL surgery using a support vector machine (SVM) classification, surgeon, and literature reference. METHODS: Seventy-five patients (aged 30.3 ± 10.2 years, and IKDC 52.0 ± 16.5 points) with acute ACL rupture under anesthesia prior to ACL surgery were analyzed. Patients were graded with pivot-shift sign glide (+), clunk (++), and (+++) gross by senior orthopedic surgeons. At the same time, the tri-axial tibial plateau acceleration was measured. Categorical data were statistically described, and the accelerometry and categorical data were associated (α = 5%). A multiclass SVM kernel with the best accuracy trained by orthopedic surgeons and assisted from literature for missing data was compared with experienced surgeons and literature interval grading. The cubic SVM classifier achieved the best grading. RESULTS: The intra-group proportions were different for each grading in the three compared strategies (p < 0.001). The inter-group proportions were different for all comparisons (p < 0.001). There were significant (p < 0.001) associations (Tau: 0.69, -0.28, and -0.50) between the surgeon and SVM, the surgeon and interval grading, and the interval and SVM, respectively. CONCLUSION: The multiclass SVM classifier improves the acceleration categorization of the (+), (++), and (+++) pivot shift sign prior to the ACL surgery in agreement with surgeon criteria.

A Balanced Arthroscopic Debridement of the Inner Layer of the Knee Retinaculum Increases the Tibiofemoral Joint Space Width.

INTRODUCTION: Traditional techniques can enlarge the medial tibiofemoral joint space width (JSW) for meniscal repairs, but a remnant ligament laxity may be developed. Alternatively, the debridement of the inner retinaculum layer may result in a balanced JSW without causing extra-ligament damage (retinaculum layers II and collateral ligament). PURPOSE: The purpose of this study was to determine whether a concentric arthroscopic debridement of the inner retinaculum layer increases the tibiofemoral JSW in patients with meniscal injuries. Secondarily, we determine whether the increase in JSW is symmetrical between compartments and describe the rate of complications and patient satisfaction. METHOD: Twenty middle-aged (15 male and five female) patients diagnosed with acute meniscal injury aged 36 ± 12 years were enrolled. The patients were submitted to an arthroscopic debridement of the inner layer of the knee retinaculum for both the medial and lateral compartments. The tibiofemoral JSW was measured intra-articularly using a custom instrument. A two-way ANOVA for repeated measures was used to compare the JSW. A Bland-Altman analysis and test-retest analysis were performed. RESULTS: The JSW increased following the debridement of the inner retinaculum layer, for both the medial and lateral compartments (p < 0.001). No complications were identified, and the patients were satisfied with the intervention. The minimal detectable change and bias of the custom instrument were 0.06 mm and 0.02 mm, respectively. CONCLUSION: The debridement allows a clinically important (>1 mm) symmetric tibiofemoral JSW enlargement. The technique suggests favoring the diagnosis of meniscus injuries and manipulating arthroscopic instruments without secondary complications after one year.

Achilles Tendon Allograft Preparation Technique for Anterior Cruciate Ligament Reconstruction: A Technical Note.

Several factors associated with graft preparation for the surgery of the anterior cruciate ligament (ACL) like the wrong thawed, prophylaxis, bone cuts, excessive bone removal as well as positioning problems like a tunnels-graft mismatch, insufficient harvesting of the donor's tendon, size graft limitations (length and diameter), uncontrolled rotation of graft in their longitudinal axis, over or under tensioned graft, fixation mistakes, bone defects, secondary arthrofibrosis or morbidity of the donor site, and others factors importantly affect the outcomes of the ACL surgery. In this sense, the Achilles tendon Allograft is an advantageous technique where many of the previous limitation factors described can be controlled during an appropriate preparation. However, to obtain the maximum potentialities of the graft a detailed knowledge of the preparation is required. Hence, we aimed to describe how to prepare the Achilles tendon Allograft to control the graft's length and diameter, bone removal, and fixation requirements.

Intraoperative pivot-shift accelerometry combined with anesthesia improves the measure of rotatory knee instability in anterior cruciate ligament injury.

PURPOSE: The knee stiffness acquired following an Anterior Cruciate Ligament (ACL) injury might affect clinical knee tests, i.e., the pivot-shift maneuver. In contrast, the motor effects of spinal anesthesia could favor the identification of rotatory knee deficiencies prior to ACL reconstruction. Hence, we hypothesized that the intra-operative pivot-shift maneuver under spinal anesthesia generates more acceleration in the lateral tibial plateau of patients with an injured ACL than without. METHODS: Seventy patients with unilateral and acute ACL rupture (62 men and 8 women, IKDC of 55.1 ± 13.8 pts) were assessed using the pivot-shift maneuver before and after receiving spinal anesthesia. A triaxial accelerometer was attached to the skin between Gerdys' tubercle and the anterior tuberosity to measure the subluxation and reduction phases. Mixed ANOVA and multiple comparisons were performed considering the anesthesia and leg as factors (alpha = 5%). RESULTS: We found a higher acceleration in the injured leg measured under anesthesia compared to without anesthesia (5.12 ± 1.56 m.s- 2 vs. 2.73 ± 1.19 m.s- 2, p < 0.001), and compared to the non-injured leg (5.12 ± 1.56 m.s- 2 vs. 3.45 ± 1.35 m.s- 2, p < 0.001). There was a presence of significant interaction between leg and anesthesia conditions (p < 0.001). CONCLUSIONS: The pivot-shift maneuver performed under anesthesia identifies better rotatory instability than without anesthesia because testing the pivot-shift without anesthesia underestimates the rotatory subluxation of the knee by an increased knee stiffness. Thus, testing under anesthesia provides a unique opportunity to determine the rotational instability prior to ACL reconstruction.

Lateral Extra-articular Tenodesis: A Technique With an Iliotibial Band Strand Without Implants.

The main goal in anterior cruciate ligament reconstruction (ACLR) should be to restore normal knee biomechanics so the chances of failure decrease. The persistence of knee instability after ACLR goes from 0.7% to 20%. Several factors have been identified and studied, but there are some selected cases in which it seems that without adding lateral extra-articular tenodesis (LET) it is not possible to control rotational instability. Data exist supporting that LET could reduce pivot shift (PS), without losing flexion/extension range of motion nor adding risk of osteoarthritis. Recently, LET has been used in addition to ACLR to add restriction to internal tibial rotation forces, and different authors have shown their techniques to achieve this task. Also, biomechanical studies have compared different techniques for LET procedures. This article aims to describe our technique performing a modified Macintosh LET as an addition to ACLR in selected patients who require extra internal tibial rotation control. This is a reproducible, easy to learn, and inexpensive procedure in terms that only a high resistance suture is needed and not any other implant, such as a stapler, anchors, or screws, reducing the risk of tunnel coalition.