Comparison of Graft Length Changes During Knee Motion Among 5 Different Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction Approaches: A Biomechanical Study

Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

Tendon and ligament injuries, prevalent requiring surgical intervention, significantly impact joint stability and function. Owing to excellent mechanical properties and biochemical stability, Nondegradable synthetic materials, including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE), have demonstrated significant potential in the treatment of tendon and ligament injuries. These above materials offer substantial mechanical support, joint mobility, and tissue healing promotion of the shoulder, knee, and ankle joint. This review conclude the latest development and application of nondegradable materials such as artificial patches and ligaments in tendon and ligament injuries including rotator cuff tears (RCTs), anterior cruciate ligament (ACL) injuries, and Achilles tendon ruptures.

Rotational Stability of the Knee in a Comparative Study of Anterior Cruciate Ligament Reconstruction Using the Double-Bundle and Single-Bundle Techniques

BACKGROUND

The purpsose of this study was to evaluate the biomechanical outcomes of patients who underwent ACL reconstruction either with the DB or SB technique. We hypothesized that the DB technique would provide better rotation control of the knee following ACL reconstruction.

METHODS

The study included seventy-five participants (26 DB, 22 SB, and 27 healthy volunteers). Only cases with at least one year of postoperative follow-up were included. The participants performed three different demand tasks: walk task, walk and change direction, and stair descent and change direction, which was tracked using a three-dimensional 4-camera optoelectronic system. The following kinematic data were analyzed: tibial rotation amplitude and maximal internal and external rotation. Knees with ACL reconstruction were compared to contralateral knees with intact ACL and healthy knees. Clinical outcomes were determined using the subjective and objective International Knee Documentation Committee (IKDC) questionnaire and a manual arthrometer (KT 1000).

RESULTS

Both surgical groups exhibited similar clinical outcomes (mean subjective IKDC 91 SB vs. 90 DB, P=0.815; KT 1000 difference: 2mm in both groups, P=0.772). The vertical component of the ground force reaction revealed no differences between the surgical and control groups (P>0.05). Tibial rotation amplitude and maximal internal and external rotation were similar between the control, SB, and DB groups in all three different demand tasks (P>0.05).

CONCLUSION

ACL reconstruction using either the SB or DB technique can restore rotational control to the level of a healthy knee. No clinical or functional differences were found between the SB and DB surgical options.

Intraarticular lengths of double-bundle grafts can change during knee flexion: Intraoperative measurements in anatomic anterior cruciate ligament reconstructions

BACKGROUND

The lengths of the anteromedial bundle (AMB) and posterolateral bundle (PLB) change during knee motion in double-bundle anterior cruciate ligament (ACL) reconstruction. However, the actual intraarticular graft length would be affected by the bone tunnel position and tunnel creation angle during ACL reconstruction. The aim of this study was to investigate the intraarticular length change of the AMB and PLB in patients who underwent anatomic double-bundle ACL reconstruction.

HYPOTHESIS

We hypothesized that the PLB would show a more dynamic length change pattern than the AMB during knee flexion at ACL reconstruction.

METHODS

Thirty-two patients (16 men and 16 women) who had isolated ACL injuries with intact menisci were investigated. Anatomic double-bundle ACL reconstructions were performed using semitendinosus tendon autografts at a mean age of 30.6 years. The graft and tunnel lengths were measured intraoperatively. Intraarticular graft lengths and length changes were calculated at 0° and 90° of knee flexion during ACL reconstruction. Intraoperative data were collected prospectively, and analyses were performed retrospectively.

RESULTS

The intraarticular length of the AMB at 0° of knee flexion was 28.1±5.5mm. At 90° of knee flexion, the AMB intraarticular length decreased to 25.6±4.8mm. The intraarticular length of the PLB decreased to 17.7±4.6mm at 90° of knee flexion compared to 22.0±4.2mm at 0° of knee flexion. Changes in the intraarticular graft length during knee flexion were detected more in the PLB (4.1mm) than in the AMB (2.0mm, p=0.01).

DISCUSSION

This study demonstrated that the intraarticular length change of the PLB during knee motion was larger than that of the AMB in anatomic double-bundle ACL reconstructions with semitendinosus tendon autografts and suspensory femoral fixation devices.

LEVEL OF EVIDENCE

IV; retrospective cohort study.

New insights in anterior cruciate ligament morphology: implications for anterior cruciate ligament reconstruction surgeries

The frequency of injury of anterior cruciate ligament (ACL), the importance of anatomy in surgical repair and potential of the injured ACL to predispose to osteoarthritis necessitates the need for understanding its precise anatomy. Available studies have focussed on tunnel positioning and hence attachment site of the ligament. Few studies which have focussed on morphology reflect ambiguities in size, fibre bundle, number and disposition. Since a near anatomical repair of the ACL is the treatment of choice, the present study was planned to describe the morphology of ACL. Twenty-two ACL (11 right and 11 left) isolated from knee joints of collection of adult embalmed lower limbs were utilised for the study. The ACL morphology and morphometry were studied for footprints and fibre bundles. Three distinct bundles of differing lengths constitute a spiral ACL complex. These bundles are positioned as- intermediate with posteromedial and anterolateral flanking in respective positions. The tibial and femoral footprints are paw-shaped and oval respectively. Tibial footprints are approximately 2.5 times larger in area than the femoral footprints. The unique morphology of ACL vis a vis its spiralization, and its mechanical advantage of in terminal extension and conjunct rotation of knee (which are peculiarly human trait) are discussed. It is recommended to utilize the concept of spiralization and differing bundle length in ACL surgeries to achieve the favourable clinical outcome.

Flexion deformity and laxity as a function of knee position at the time of tensioning of rigid anatomic hamstring ACL grafts

Background

Anatomic ACL grafts routinely display the anisometric length-tension behaviour seen in the native ligament with maximum length in full knee extension. Recent improvements in hamstring graft preparation and fixation have improved graft rigidity to the point where total graft lengthening after implantation may be less than 1 mm. Despite this it remains common practice to fix these grafts in a knee flexed position.

Methods

Nineteen participants underwent all-inside ACL reconstruction with optimally preconditioned 4 strand semitendinosus grafts using bi-cortical adjustable suspensory loop fixation. Using a computer navigation system, baseline measures of anisometricity, extension range, and tibial rotation were made. The graft was tensioned and provisionally fixed with the knee flexed 5° beyond its anisometric point and extension range recorded. The graft was then definitively fixed with the knee fully extended and extension range and tibial rotation recorded again. Anterior laxity measurements were made pre-operatively and postoperatively using a manual arthrometer and compared to those from the contralateral limb.

Results

Fixing the graft with the knee flexed produced a mean FD of 10.9° (p < 0.0001) and fixing in extension restored full extension (p = 0.661). Fixing in extension restored anterior laxity at 30° (p = 0.224) and at 90° (p = 0.668). There were very strong correlations between post-operative and control extension range (r = 0.931, p < 0.0001) and anterior laxity and 30° (r = 0.830, p < 0.0001) measures. Constraint of tibial internal rotation increased by 2.9° during the pivot-shift (p < 0.001) and increased with pivot shift grade (r = 0.474, p = 0.040).

Conclusion

Fixing rigid anatomic hamstring grafts in a knee flexed position routinely produces a flexion deformity. Tensioning and fixing grafts with the knee fully extended restores full extension and anterior laxity at 30° and 90°. Rotational constraint is significantly improved and correlates with the pivot-shift grade.

Clinical relevance

Rigid anatomic grafts should be tensioned and fixed with the knee fully extended.