High initial graft tension increases external tibial rotation on the axial plane after anatomical anterior cruciate ligament reconstruction

Initial graft tension affects patellofemoral alignment during anatomical anterior cruciate ligament reconstruction

BACKGROUND

This study aimed to evaluate the effects of the differences in initial graft tension (IGT) on patellofemoral alignment in the axial plane after anatomical anterior cruciate ligament reconstruction (ACLR).

METHODS

A total of 102 patients who underwent primary anatomical ACLR using a bone-patellar-tendon-bone autograft were enrolled. The grafts were fixed with maximum manual force at full knee extension (higher graft tension; H group) and with 5-20 N at 20° knee flexion which corresponded to 80 N at full knee extension (lower graft tension; L group) pulls in 39 and 63 patients, respectively. All patients underwent computed tomography of the bilateral knee joints with knee extension 1 week postoperatively. The patellofemoral alignment (sulcus angle, lateral trochlear inclination angle, lateral patellofemoral angle (LPFA), condylar-patellar angle (CPA) (lateral facet, patellar tilt), congruence angle, and bisect offset index) on the axial computed tomography images were evaluated, and the side-to-side differences (SSDs) between the injured knee and the contralateral knee were calculated.

RESULTS

Congruence angle SSD was remarkably higher in the H group than in the L group (3.8 ± 4.7 vs. 0.4 ± 5.7, P < 0.01). Furthermore, the LPFA SSD and CPA (patellar tilt) SSD were significantly higher in the H group (-1.8 ± 3.1 vs. -0.4 ± 2.7, P = 0.04 and -1.6 ± 2.8 vs. -0.3 ± 2.7, P = 0.04, respectively).

CONCLUSIONS

A higher IGT during anatomical ACLR induces a lateral shift and tilt of the patella against the femur immediately after surgery compared with the lower IGT.

Postoperative quadriceps weakness and male sex are risk factors for patellofemoral articular cartilage lesions after anatomical anterior cruciate ligament reconstruction

PURPOSE

Patellofemoral (PF) compartment cartilage lesions are a frequent problem after anterior cruciate ligament (ACL) reconstruction. This study aimed to determine the factors that influence PF cartilage lesions after anatomical ACL reconstruction.

METHODS

This study enrolled a total of 114 patients who did not manifest PF compartment cartilage lesions during anatomical ACL reconstruction and underwent second-look arthroscopy 18 months postoperatively. Arthroscopy using the International Cartilage Repair Society (ICRS) classification was used to assess cartilage lesions. The correlation between surgical findings, radiographic factors, and clinical factors and change of ICRS grade was analysed. Multivariate regression analysis was conducted to reveal the independent risk factors for PF cartilage lesions among patients' demographic data and parameters that correlated with the change of ICRS grade in the correlation analyses.

RESULTS

ICRS grade changes in PF cartilage were significantly correlated with age, sex, quadriceps strength at 1 year postoperatively, hamstrings strength at pre- and 1 year postoperatively, and single leg hop test at 1 year postoperatively. However, no significant correlation was found between the time between injury and surgery, posterior tibial slope angle, pre- and postoperative Tegner activity scale, graft type, initial graft tension, meniscus injury, meniscus injury treatment, pre- and postoperative range of motion, anteroposterior laxity and preoperative quadriceps strength, and the change in ICRS grade. Multivariate regression analysis revealed male (P = 0.019) and quadriceps strength weakness at 1 year postoperatively (P = 0.009) as independent risk factors for PF cartilage lesions.

CONCLUSIONS

Quadriceps strength weakness 1 year after ACL reconstruction and males were correlated with a new PF cartilage lesion after anatomical ACL reconstruction, with no significant correlation between bone-patellar tendon-bone autograft, initial graft tension, or extension deficit and new PF cartilage lesion. Rehabilitation that focuses on quadriceps strength after ACL reconstruction is recommended to prevent new PF cartilage lesions.

LEVEL OF EVIDENCE

Level IV.

High initial graft tension is a post-operative risk factor for high UTE T2* value of the graft 6 months after anterior cruciate ligament reconstruction

BACKGROUND

To evaluate the risk factor of "ligamentization" using the ultrashort echo time (UTE)-T2* imaging.

METHODS

Fifty-nine patients (23 males and 36 females, age of 21.9 ± 10.6 years old) who underwent anterior cruciate ligament (ACL) reconstruction with hamstring tendon were evaluated. The UTE T2* values of the reconstructed ACL at 6 months postoperatively were calculated. Circular regions of interest (5-10 mm²) were set at the proximal, mid-substance, and distal regions of the reconstructed ACL. The UTE T2* values of the entire reconstructed ACL were calculated as the average of these three points. Patients were divided into high (27 knees) and low (32 knees) UTE T2* groups by calculating whether their UTE T2* values were greater than the median of the UTE T2* values of all patients. Risk factors for high UTE T2* values were evaluated. Clinical outcomes were compared between the two groups.

RESULTS

There were no significant differences in any measured parameters and clinical outcomes between the two UTE T2* groups. Logistic regression analysis revealed that graft tension was a significant risk factor for patients with high UTE-T2* values (P = 0.047, odds ratio [OR] = 2.285). The UTE-T2* values of the 20 N graft tension using the Tension loc system were significantly lower than those of the 40 N using double-spike plate (DSP) with screws at each site and the 30 N using the Tension loc system at the distal site.

CONCLUSIONS

Higher graft tension was an independent risk factor for high UTE T2* values of the reconstructed ACL.

An Efficient Needleless Grasping Suture Technique for Graft Preparation in Anterior Cruciate Ligament Reconstruction

Objective

Several needleless techniques have been developed to outcome the inherent disadvantages of the traditional needle stitching technique for graft preparation, such as tendon damage through the needle, time consumption, and the potential risk of needlestick injury. The purpose of the present study is to compare the graft preparation time and the biomechanical performance between an efficient needleless technique and the traditional needle stitching technique for graft preparation in anterior cruciate ligament reconstruction (ACLR).

Methods

The time required to perform a complete suture on 20 hamstring tendons during ACLRs was measured. The grafts from one side were prepared using the needle stitching technique. The grafts from the other side used the needleless grasping suture technique. For the second part of the study, 12 fresh-frozen porcine flexor tendons were divided into two groups using two techniques and were mounted in an electric tensile test system. Each group was pretensioned to 100 N to simulate the maximum initial graft tension. The suturing state of sutures and graft (intact and damaged) and the load-elongation curve were recorded for each group. A Student’s t-test was used to compare the means of the two groups.

Results

In operation, the needleless grasping suture technique group (19.8 ± 4.8, range: 13.5–32.9 s) was significantly faster (p &lt; 0.05) than the needle stitching technique group (52.7 ± 12.7, range: 36.0–87.5 s). The state of sutures in each group was intact. The mean elongation was 11.75 ± 1.38 (range: 9.47–12.99) mm and 10.59 ± 1.02 (range: 9.12–11.76) mm in the needleless stitching technique group and the needle grasping suture technique group, respectively. There was no statistically significant difference in the elongation between the two groups (p &gt; 0.05).

Conclusion

The needleless grasping suture technique was a convenient and efficient method for graft preparation in ACLR.