Safety and Efficacy of Early Rehabilitation With Assistance From a Single-Joint Hybrid Assistive Limb in Patients With Total Knee Arthroplasty: A Randomized Controlled Clinical Pilot Study.

Background This study aimed to evaluate the safety and effectiveness of knee exercise within four hours after total knee arthroplasty (TKA) using a single-joint hybrid assistive limb (HAL-SJ). Materials and methods This pilot single-blind randomized controlled trial included participants who underwent TKA for osteoarthritis and were randomly allocated to the early rehabilitation (n = 14) or control rehabilitation (n = 16) group. Knee rehabilitation exercises using the HAL-SJ began within four hours postoperatively in the early group and seven days after surgery in the control group. Knee circumference, range of motion (ROM), pain, muscle strength, and extension lag were assessed before and one and two weeks after surgery. Results Circumferences at 1 and 10 cm from the upper edge of the patella did not differ between the groups before surgery or one week postoperatively. The extension lag and knee flexion ROM after one week were significantly better in the early intervention group than in the control group. However, the quadriceps and hamstring isometric knee strength and pain scores did not differ between the groups at one and two weeks postoperatively. HAL-SJ-related complications were not reported. Conclusion Rehabilitation knee exercises using the HAL-SJ within four hours after TKA improved extension lag and knee flexion ROM without exacerbating knee swelling and pain.

Limited preoperative knee extension in anterior cruciate ligament reconstruction using a hamstring tendon affects improvement of postoperative knee extensor strength.

PURPOSE: This study aimed to determine the factors affecting knee extensor strength 6 months after anterior cruciate ligament (ACL) reconstruction using autograft hamstring tendon. METHODS: 144 patients who could undergo regular follow-up after ACL reconstruction were divided into 2 groups: those with greater than 90% (Group A: n = 95) and less than 85% (Group B: n = 49) isokinetic knee contraction at 60°/s 6 months post-ACL reconstruction. Basic information, injury status, limited preoperative knee extension, and knee extensor strength at 3 and 6 months postoperatively were compared between the groups. Multivariate logistic analysis was performed and included variables that showed statistically significant differences between the groups in the univariate analysis. In addition, the cut-off value for the limb symmetry index (LSI) at 3 months postoperatively needed to exceed an LSI of 90% at 6 months postoperatively was calculated using the receiver operating characteristics curve. RESULTS: Age, preoperative waiting period, limited preoperative knee extension, and knee extensor strength at 3 months postoperatively were significantly different between the two groups. The multivariate logistic analysis showed that all the variables affected the improvement in knee extensor strength at 6 months postoperatively. Limited preoperative knee extension was the most significant factor (odds ratio: 15.1, 95% confidence interval: 2.57-118.56, p < 0.01). The LSI cut-off value at 3 months postoperatively was 72.0%. CONCLUSION: Key factors in achieving the necessary knee extensor strength criteria for return to sports at 6 months post-ACL reconstruction include addressing limited preoperative knee extension and achieving an LSI ≥ 72% in knee extensor strength at 3 months postoperatively. LEVEL OF EVIDENCE: Level III.

Outcome comparison of femoral nerve block and adductor canal block during anterior cruciate ligament reconstruction: adductor canal block may cause an unexpected decrease in knee flexor strength at 6 months postoperatively.

INTRODUCTION: Peripheral nerve blocks are frequently used in anterior cruciate ligament (ACL) reconstruction. While femoral nerve block (FNB) has been associated with knee extensor strength reduction in the early postoperative period, no consistent view of knee extensor strength several months after ACL reconstruction exists. This study aimed to compare the impact of intraoperative FNB and adductor canal block (ACB) during ACL reconstruction on knee extensor strength at 3 and 6 months postoperatively. MATERIALS AND METHODS: This retrospective study included 108 patients divided into FNB (70 patients) and ACB (38 patients) groups based on their postoperative pain management methods. Knee joint extensor and flexor strength were measured at 3 and 6 months postoperatively, using BIODEX at angular velocities of 60°/s and 180°/s. From these results, peak torque, limb symmetry index (LSI), peak knee extensor torque (time to peak torque and angle of peak torque), hamstrings-to-quadriceps (HQ) ratio, and amount of work were computed for two-group comparison. RESULTS: There were no statistically significant differences in peak torque, LSI of knee extensor strength, HQ ratio, and amount of work between the two groups. However, maximum knee extension torque at 60°/s occurred significantly later in the FNB than in the ACB group at 3 months postoperatively. Additionally, the LSI of the knee flexor at 6 months postoperatively was significantly lower in the ACB group. CONCLUSIONS: In ACL reconstruction, FNB may delay the time to peak torque for knee extension at 3 months postoperatively, which is likely to improve over the treatment course. In contrast, ACB may result in unexpected loss of knee flexor strength at 6 months postoperatively and should be considered with caution. LEVEL OF EVIDENCE: Level III.

Non-use of intra-articular drain after anterior cruciate ligament reconstruction does not affect postoperative knee pain and muscle strength on early period.

Introduction: This study aimed to determine the effect of using an intra-articular drain after anterior cruciate ligament (ACL) reconstruction on early postoperative pain, range of motion (ROM), muscle strength, and complications. Materials and methods: Between 2017 and 2020, of the 200 consecutive patients who underwent anatomical single-bundle ACL reconstruction, 128 patients underwent primary ACL reconstruction with hamstring tendons and were evaluated for postoperative pain and muscle strength at 3 months postoperatively. Sixty-eight patients who received intra-articular drain before April 2019 were classified as group D and 60 patients without an intra-articular drain after ACL reconstruction after May 2019 were classified as group N. Patient background, operative time, postoperative pain, number of additional analgesics used, presence of intra-articular hematoma, ROM at 2, 4, and 12 weeks postoperatively, extensor and flexor muscle strength at 12 weeks postoperatively, and perioperative complications were compared between the two groups. Results: The postoperative pain at 4 h after surgery was significantly greater in group D than in group N although no significant difference was found in the pain felt in the immediate postoperative period and at 1 day and 2 days postoperatively and in the number of additional analgesics used. No significant difference in the postoperative ROM and muscle strength was noted between the two groups. Six patients with intra-articular hematomas in group D and four patients in group N needed puncture by 2 weeks postoperatively, and no significant difference was found between the two groups. Conclusion: Postoperative pain was greater at 4 h postoperatively in group D. Furthermore, the intra-articular drain did not affect muscle strength, ROM, and complications on the early postoperative period. The usefulness of intra-articular drain after ACL reconstruction was considered low. Level of Evidence: Level IV.

Differences in collagen types in the semitendinosus, quadriceps, and patellar tendons: A report using samples from an 11-year-old patient.

BACKGROUND: This study aimed to determine the differences in the proportions of types I and type III collagen in the semitendinosus tendon (ST), quadriceps tendon (QT), and patellar tendon (PT), which are frequently used as autografts for anterior cruciate ligament (ACL) reconstruction. METHODS: Orthopedic surgeons diagnosed habitual dislocation of the left patella and surgically treated an 11-year-old boy. Medial patellofemoral ligament reconstruction, medial patellar tibial ligament reconstruction, and arthroscopic lateral release were performed simultaneously. Tissue samples obtained during treatment that were no longer necessary were used as samples for this study. The samples were fixed, paraffin-embedded, and immunostained for type I and type III collagen. Stained samples were observed under a confocal microscope and evaluated visually and quantitatively to determine the percentages of type I and type III collagen. RESULTS: Visually, the ST had a higher percentage of type III collagen than the PT and QT. The QT and PT were similar in appearance; both consisted mostly of collagen type I. Quantitative evaluation using images showed that the PT comprised 100% type I collagen. The QT comprised 1% type III collagen. The ST comprised 34% type III collagen. CONCLUSION: In this patient, the QT and PT had higher percentages of type I collagen, which is considered physically strong. Type III collagen, which is considered physically weak, was most common in the ST. These factors may be associated with the high re-injury rates after ACL reconstruction using the ST for physically immature patients.

Anterior cruciate ligament reconstruction with ultrasound-guided femoral nerve block does not adversely affect knee extensor strength beyond that seen with intravenous patient-controlled analgesia at 3 and 6 months postoperatively.

BACKGROUND: This study aimed to investigate the effect of anterior cruciate ligament (ACL) reconstruction with an ultrasound-guided femoral nerve block (FNB) on knee extensor strength weakness 3 and 6 months, and graft rupture in the 1 year following ACL reconstruction. METHODS: One hundred and seven patients who underwent ACL reconstruction were included in this retrospective study. The patients were divided into two groups stratified by the method of postoperative pain management. The FNB group included 66 patients, and there were 41 patients in the intravenous patient-controlled analgesia (iv-PCA) group. The isokinetic peak torque of knee flexor and extensor was measured preoperative, 3 and 6 months after ACL reconstruction. Muscle strength measurements were performed using the BIODEX dynamometer at a velocity of 60°/s and 180°/s. Peak torque of knee extensor and flexor strength, estimated pre-injury capacity (EPIC), body weight ratio (BW), and graft rupture incidence were compared between the two groups. RESULTS: There were no statistically significant differences in the knee extensor and flexor strength for all items at 3 and 6 months after ACL reconstruction. There was also not a statistically significant difference in the graft rupture incidence between the two groups: FNB group was two patients, 3.0% vs. iv-PCA group was one patient, 2.4% (p = 0.86). CONCLUSION: ACL reconstruction with ultrasound-guided FNB does not affect knee extensor strength at 6 months, nor graft rupture at 1 year postoperatively.

The effect of gracilis tendon harvesting in addition to semitendinosus tendon harvesting on knee extensor and flexor strength after anterior cruciate ligament reconstruction.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction using hamstring tendons may involve harvesting of the gracilis tendon in addition to the semitendinosus tendon (ST) depending on the size of the ST graft. However, the effect of gracilis harvesting in addition to ST harvesting on muscle strength, such as the hamstring-to-quadriceps (HQ) ratio, remains unclear. Hence, this study aimed to investigate the effect of gracilis harvesting on subsequent knee muscle strength. MATERIALS AND METHODS: Eighty-two patients who underwent ACL reconstruction were included in this retrospective study. They were divided into the following two groups depending on the tendon graft used for ACL reconstruction: the ST group (41 patients) and the semitendinosus tendon/gracilis tendon (STG) group (41 patients). The isokinetic peak torque of the knee extensor and flexor was measured using a BIODEX dynamometer at a velocity of 60°/s and 180°/s, respectively, 3 and 6 months after ACL reconstruction. The groups were compared in terms of the limb symmetry index (LSI) and HQ ratio. RESULTS: The significant difference in the knee flexor of the LSI at 6 months after ACL reconstruction was as follows: ST group, 120.3 ± 28.3 vs STG group, 105.6 ± 19.0 (p < 0.01) at 60°/s and ST group, 122.9 ± 35.2 vs STG group, 106.2 ± 24.6 (p = 0.02) at 180°/s. There were significant differences in the HQ ratio at 180°/s as follows: ST group, 0.67 ± 0.15 vs STG group, 0.60 ± 0.13 (p < 0.01) at 3 months and ST group, 0.67 ± 0.13 vs STG group, and 0.59 ± 0.12 (p < 0.01) at 6 months after ACL reconstruction. CONCLUSIONS: Gracilis tendon harvesting may contribute to a decrease in knee flexor strength and HQ ratio with fast contraction. Thus, the need for gracilis tendon harvesting in ACL reconstruction should be carefully considered. LEVEL OF EVIDENCE: III.