Intraoperative kinematic analysis of posterior stabilized total knee arthroplasty with asymmetric helical post-cam design.

PURPOSE: To investigate intraoperative kinematics during passive flexion using a surgical navigation system for knees undergoing posterior stabilized (PS) total knee arthroplasty (TKA) with an asymmetric helical post-cam design using navigation system. METHODS: In total, 45 knees with both pre- and postoperative kinematic data available were included in the study. Intraoperative kinematic measurements were performed during the course of surgery using the software incorporated in the navigation system. Measurements were performed at the following two time points: (1) before TKA procedure and (2) after TKA implantation. Among the kinematic parameters studied, anterior/posterior translation and axial rotation during flexion were subjected to the analysis. RESULTS: Before surgery, physiologic anterior/posterior translational pattern of the tibia during flexion (rollback of the femur) was found in only 15.6% of the knees. After TKA implantation, postoperative kinematic measurement showed no significant change in the tibial translational during knee flexion. Similarly, with regard to rotation, non-physiologic external tibial rotation in early flexion was observed in the majority of the knees before surgery, and this abnormal kinematic pattern remained after the TKA procedure. CONCLUSIONS: The intraoperative three-dimensional motion analysis using a navigation system showed that the physiologic kinematic pattern (anterior translation and internal rotation of the tibia during flexion) of the knee was distorted in osteoarthritic knees undergoing TKA. The abnormal kinematic pattern before surgery was not fully corrected even after implantation of the PS TKA designed to induce natural knee motion; however, no clear relationship between the intraoperative kinematic pattern and knee flexion angle at one year was demonstrated, and the effect of knee kinematics on postoperative knee function and patient's satisfaction is still unclear.

Local Infiltration Analgesia Versus Continuous Femoral Nerve Block in Pain Relief After Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Although both local infiltration analgesia (LIA) and continuous femoral nerve block (FNB) are common analgesic modalities for pain relief after total knee arthroplasty (TKA), we are aware of no parallel-group, randomized controlled trial that has solely compared the efficacy of LIA and continuous FNB. METHODS: We conducted a prospective, 2-arm, parallel-group, randomized controlled trial involving patients scheduled for TKA. A total of 45 patients were randomly assigned to either the LIA or the continuous FNB group. Except for the analgesic modality, perioperative managements were identical in both groups. The primary outcome was postoperative pain score at rest 1 day after surgery, measured using a 100-mm visual analog scale. RESULTS: Patients in the LIA group had a significantly lower visual analog scale score at rest 1 day after surgery than those in the continuous FNB group (34 ± 10 vs 42 ± 13 mm; P = .028). The opioid consumption during the initial 24 hours was significantly lower in the LIA group (12 ± 4 vs 16 ± 7 mg; P = .031). There were no differences in the rate of complications between the groups. CONCLUSION: LIA was associated with better pain relief with a comparable complications rate for patients undergoing TKA than FNB. We recommend LIA for pain relief after TKA.

Evaluation of the Anterior Cruciate Ligament Injury Risk During a Jump-Landing Task Using 3-Dimensional Kinematic Analysis Versus the Landing Error Scoring System.

Background: The Landing Error Scoring System (LESS) has been utilized on the field or in the clinic to identify patients with an increased risk for anterior cruciate ligament (ACL) injuries; however, its validity and efficacy have not been fully confirmed. Purpose: To assess the efficacy of the LESS in identifying the ACL injury risk by examining the correlation between the LESS score and motion patterns on 3-dimensional kinematic analysis. Study Design: Controlled laboratory study. Methods: The jump-landing motion was analyzed for 16 female basketball or badminton players who volunteered to participate in the study. All study participants were aged 19 or 20 years. The sequence of motion was evaluated with the LESS, while kinematic data were simultaneously acquired with a 3-dimensional motion analysis system utilizing the point cluster method. The correlation between the LESS score and knee kinematics was statistically analyzed. Results: When a LESS score ≥6 was defined to be a risk factor for ACL injuries, 7 of the 16 participants (43.8%) were found to exhibit risky motion patterns. Significant correlations were noted between the LESS score and knee valgus (r = 0.87; P < .0001) and internal tibial rotation (r = 0.57; P = .02) at landing. By contrast, a substantial variability was present in knee flexion, showing no correlation with the LESS score. Conclusion: Significant correlations were found between the LESS score and knee valgus and internal tibial rotation during a jump-landing task. Clinical Relevance: The LESS can be regarded as an effective measure to identify risky motion patterns that may increase the likelihood of ACL injuries.

The Effectiveness of Intramedullary Screw Fixation Using the Herbert Screw for Fifth Metatarsal Stress Fractures in High-Level Athletes.

BACKGROUND: Intramedullary screw fixation is the most common operative procedure used for treatment of fifth metatarsal stress fractures in athletes. However, the optimal implant in intramedullary screw fixation is still being investigated. PURPOSE: To review experiences with intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures in high-level athletes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The authors retrospectively analyzed 37 high-level athletes (Tegner activity score ≥7) who underwent intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures between August 2005 and August 2017. The minimum follow-up period of the patients was 2 years. In assessing the surgical results, time to obtain bone union, time to return to original level of sport participation, and treatment failures/complications were reviewed. Additionally, the effect of intraoperative plantar gap widening caused by the screw insertion was analyzed. The surgical results of the 2 groups, the no-gap group (intraoperative plantar gap widening, <1 mm) and the gap group (intraoperative plantar gap widening, ≥1 mm), were compared, while correlations between intraoperative plantar gap widening and the surgical results were statistically analyzed. RESULTS: Bone union and return to the original sport were attained in all patients without treatment failures/complications such as delayed union, nonunion, or refracture. The mean time to obtain bone union was 10.1 weeks, and the mean time to return to sport was 10.9 weeks. In comparing the no-gap group (n = 16) and the gap group (n = 21), no significant differences in the time to obtain bone union (P = .392) or to return to sport (P = .399) were noted. Additionally, there was no correlation between intraoperative plantar gap widening and the time to obtain bone union (r = 0.131; P = .428) or to return to sport (r = 0.160; P = .331). CONCLUSION: The use of the Herbert screw for intramedullary screw fixation to treat fifth metatarsal stress fractures in high-level athletes provided satisfactory results enabling all the athletes to return to the original sport without treatment failures/complications. Additionally, intraoperative plantar gap widening does not affect the surgical results using this technique.

Double threaded screw fixation for bilateral stress fracture of the medial malleolus.

An 18-year-old college basketball player presented with continued ankle pain. A radiographic examination showed bilateral medial malleolus stress fractures. Considering the prolonged history and refractory nature of this injury, surgery was adopted as a treatment option. At surgery, the fracture site was percutaneously fixed using two cannulated double threaded screws. Surgery for each side was sequentially performed two months apart. Prompt bony healing was attained after surgery, and the patient could return to his previous sports level six months after the first surgery without subsequent recurrence.