Effect of tibial insertion site for lateral suture stabilization on the kinematics of the cranial cruciate ligament deficient-stifle during early, middle and late stance: an in vitro study

Ex vivo biomechanical investigations of combined extra- and intracapsular stabilization in canines with cranial cruciate ligament deficiency

Intracapsular reconstruction (ICR) has long been recommended as a treatment for cranial cruciate ligament deficiency (CCLD) in dogs, but it has fallen out of favor due to its inferior long-term functional outcomes. These outcomes may be attributed to the poor stiffness and strength of the graft in the early period before ligamentization is completed. Additional placement of extracapsular sutures to mechanically protect the graft during the ligamentization process may be a viable method to address this problem. However, the biomechanical effect of this combined surgical approach remains unknown. This study aimed to evaluate the 3D kinematics of the CCLD stifle in dogs in response to ICR and combined extra- and intracapsular reconstruction (CEICR). Twelve hindlimbs were collected from nine cadavers of mature dogs. The limbs were tested using a custom-made testing apparatus that reproduces their sagittal plane kinematics during the stance phase. Four statuses of stifle joints were tested, namely, (a) cranial cruciate ligament (CCL) intact; (b) CCLD; (c) CCLD stifle stabilized by CEICR; and (d) CCLD stifle stabilized by ICR only. Three-dimensional stifle kinematics at the 5 instances of the stance phase were measured with an optoelectronic system. The results showed that ICR marginally corrects the increased adduction, internal rotation, and caudodistal stifle joint center displacement that occur as a result of CCLD. CEICR led to better restoration of the stifle kinematics, especially with respect to the internal rotation and cranial translation stabilities. Furthermore, CEICR only resulted in minor excessive restraints on other motion components. The findings indicated that the additional lateral fabellotibial suture offers immediate stability to the stifle, consequently lowering the risk of graft over-elongation in the short term postoperatively. Considering the propensity for the extracapsular suture to degrade over time, further in vivo studies are warranted to explore the long-term effects of the CEICR procedure.

Ex vivo biomechanical evaluation of extracapsular stabilization with quasi-isometric points in canine cranial cruciate ligament-deficient stifles

BACKGROUND

Cranial cruciate ligament (CCL) disease is one of the most common causes of lameness in dogs. The extracapsular stabilization (ECS) utilizing bone anchors and monofilament nylon leader was an alternative treatment for CCL-deficient (CCLD) dogs. However, the biomechanical response of the canine stifle to such a surgical repair strategy in conjunction with the use of recently reported quasi-isometric anchoring points remains unclear. The objectives of the study were to evaluate the mobility and stability of CCL-intact, CCLD, and CCLD stifles repaired with ECS at two different pairs of quasi-isometric points (quasi-IPs).

METHODS

Twelve stifle specimens from 7 dogs underwent mobility and stability tests under 4 different conditions, namely, CCL-intact, CCLD, and ECS-repaired at 2 different pairs of quasi-IPs (referred to as ECS-IP1 and ECS-IP2). The mobility tests evaluated 6 degrees-of-freedom stifle kinematics during flexion and extension. The stability tests involved cranial drawer and tibial internal rotation (IR) tests at various stifle opening angles and quantifying the cranial tibial translation (CTT) and tibial IR angles under constantly applied loadings.

RESULTS

The ECS repaired at quasi-IPs was shown to restore cranial instability of the stifles with averaged CTT magnitudes < 1.4 mm. During the tibial IR test, the ECS treatments resulted in significantly less tibial IR compared to those in intact CCL stifles. The mobility tests showed similar results.

CONCLUSION

The 2 chosen pairs of quasi-IPs were shown to effectively correct the excessive CTT caused by CCLD stifles, whereas the excessive tibial external rotation in comparison to those of intact stifles should be considered for its subsequent influence on joint alignment and the contact pressure applied to the stifle joint.

Comparison of Two Stifle Exploratory Methods Using Mini-Arthrotomy for Diagnosis of Canine Medial Meniscal Pathology: An Ex Vivo Study

OBJECTIVE

 The main aim of this study was to compare the accuracy of stifle exploratory using either a stifle distractor (SD method) or a combination of Hohmann and Senn retractors (HS method) for diagnosing canine medial meniscal tears in cranial cruciate ligament-deficient stifles.

STUDY DESIGN

 Fifteen pairs of canine cadaveric pelvic limbs were used and cranial cruciate ligament were transected in all stifles. Paired limbs were then randomly assigned to one of five groups based on the tears created in the caudal pole of the medial meniscus: no tear, peripheral detachment, or a variation in three vertical longitudinal tears. A craniomedial mini-arthrotomy was performed by two observers and diagnosis of the medial meniscal status was made utilizing the HS and SD methods. Correct diagnosis of the meniscal tear was compared for both methods and observers.

RESULTS

 Correct diagnoses were made using the HS and SD methods in 24/30 and 24/30 cases for observer 1 respectively; and in 17/30 and 19/30 cases for observer 2 respectively. There was no significant difference in the correct diagnosis of meniscal tears within each observer between the two methods.

CONCLUSION

 Both HS and SD methods have equal accuracy for the diagnosis of canine medial meniscal pathology for a board-certified surgeon. Unassisted surgeons using the SD method for the evaluation of the medial meniscus are at no diagnostic disadvantage compared with assisted surgeons utilizing the HS method.

Three-dimensional kinematic evaluation of lateral suture stabilization in an in vitro canine cranial cruciate deficient stifle model

The impact of surgical correction of cranial cruciate ligament rupture (CCLR) on 3D kinematics has not been thoroughly evaluated in dogs. The success of current techniques remains limited, as illustrated by suboptimal weightbearing and progression of osteoarthritis. The inability to restore the stifle's 3D kinematics might be a key element in understanding these suboptimal outcomes. The objective of this study was to evaluate the impact of lateral suture stabilization (LSS) on the 3D kinematics of the canine stifle joint. We hypothesized that LSS would not restore 3D kinematics in our model. Ten cadaveric pelvic limbs collected from large dogs (25-40 kg) were tested using a previously validated apparatus that simulates gait. Three experimental conditions were compared: (a) intact stifle; (b) unstable stifle following cranial cruciate ligament transection (CCLt) and (c) CCLt stabilized by LSS. Three-dimensional kinematics were collected through 5 loading cycles simulating the stance phase of gait and curves were analyzed using a Wilcoxon signed-rank test. LSS restored baseline kinematics for the entire stance phase for cranial and lateromedial translation, flexion, and abduction. It restored distraction over 90% of the stance phase. Internal rotation was limited, but not restored. This in vitro study had limitations, as it used a simplified model of stifle motion and weight-bearing. The results of this study report that LSS can restore physiologic 3D kinematics largely comparable to those of healthy stifles. Suboptimal outcome in patients following CCLR stabilization by LSS may therefore result from causes other than immediate postoperative abnormal 3D kinematics.

Titanium-Alloy Anchoring System as a Suitable Method of Extracapsular Repair

Objective: To characterize the effect of a titanium-alloy anchoring system (TAS) on the motion of the cranial cruciate ligament (CrCL) deficient stifle. To compare the motion with the TAS to that of the CrCL-intact and CrCL-deficient stifle.

Study Design: Each canine pelvic limb was mounted in a loading jig under 30% body weight. Motion data was collected using an electromagnetic tracking system at stifle angles of 125°, 135°, and 145° with the CrCL-intact, CrCL-deficient and the TAS applied.

Results: Total translation of the CrCL-deficient stifle following the TAS was reduced, but remained greater than the CrCL-intact stifle at angles of 125°, 135°, and 145°. Internal rotation of the TAS groups was greater than the CrCL-intact group at 145°, but not 125° and 135°. Varus motion of the TAS group was decreased compared to the CrCL-deficient group, but increased compared to the CrCL-intact group at angles of 125°, 135°, and 145°.

Conclusion: Total translation and internal rotation of the CrCL-deficient stifle following the TAS differed from that of the CrCL-intact stifle. However, the TAS reduced total translation and internal rotation of the tibia relative to the femur in the CrCL-deficient stifle to levels that may yield clinically acceptable results.

Investigation of a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament-deficient stifle joints in adult cattle

OBJECTIVE

To evaluate a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament (CCL)-deficient stifle joints in adult cattle.

SAMPLE

13 cadaveric bovine stifle joint specimens.

PROCEDURES

In the first of 3 study phases, the most isometric points on the distal aspect of the femur (distal femur) and proximal aspect of the tibia (proximal tibia) were determined from measurements obtained from lateromedial radiographs of a stifle joint specimen maintained at angles of 135°, 90°, 65°, and 35°. During phase 2, 800-lb-test monofilament nylon leader line was cut into 73-cm-long segments. Each segment was secured in a loop by use of 2, 3, or 4 crimping sleeves such that there were 12 replicates for each construct. Each loop was distracted to failure at a constant rate of 1 mm/s. Mean force at failure and elongation and mode of failure were compared among the 3 constructs. During phase 3, bone tunnels were created in the distal femur and proximal tibia at the isometric points identified during phase 1 in each of 12 CCL-deficient stifle joint specimens. The 3-sleeve construct was applied to each specimen. Specimens were distracted to failure at a constant rate of 1 mm/s.

RESULTS

Among the 3 constructs evaluated, the 3-sleeve construct was considered optimal in terms of strength and amount of foreign material. In phase 3, all replicates failed because of suture slippage.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of 800-lb-test monofilament nylon leader line as a prosthesis might be a viable alternative for extracapsular stabilization of CCL-deficient stifle joints in adult cattle. Further in vivo studies are necessary.

Treatment of cranial cruciate ligament rupture in the feline stifle

Objective: To determine whether a lateral suture placed with bone anchors between quasi-isometric points in a cat is superior to a standard fabella-tibial suture for the stabilization of cranial cruciate ligament (CrCL) rupture compared to an intact stifle joint.

Study design: Biomechanical cadaveric study.

Methods: Six stifle joints with intact cruciate ligaments from three skeletally mature cats were placed in a loading mounting set and tested with axial loads of 20N and 60N at three different joint angles (75°,130° and 160°). The procedure was repeated with a transected CrCL; a stabilized stifle joint after a combination of three lateral suture techniques (fabella-tibial suture technique [SFT]; femoro-tibial suture technique 1 [FTS-1] and femoro-tibial suture technique 2 [FTS-2]). Radiographic examination of the relative position of the tibia to the fixed femur was compared.

Results: Stabilization of the stifle joint with lateral sutures had comparable stability to the intact specimens in the cranio-caudal direction (p = 0.2) but not in the proximo- distal direction for the SFT (p = 0.04) and FTS-2 technique (p = 0.03). There was no significant difference between the three stabilization techniques (p >0.05).

Clinical significance: Lateral sutures placed with bone anchors at quasi-isometric points performed better than SFT and FTS-2 in stabilizing the feline stifle after CrCL rupture in the proximo-distal plane. Biomechanical stability in the cranio-caudal plane after placement of a lateral suture across the feline stifle was similar to the intact CrCL.

Tensions generated in a lateral fabellotibial suture model. Comparison of methods of application of tension, fixation of tension and suture material

OBJECTIVES

To compare suture tension on a simulated lateral fabellotibial suture model using various methods of application of tension, fixation, and suture materials.

METHODS

Veterinarians constructed simulated lateral fabellotibial suture constructs on a tying stand with a force sensor. Participants used combinations of 45 kg test monofilament nylon, metric 7 braided polyethylene, crimps, crimper, or knots, with their choice of instruments to secure the constructs. The tension in completed constructs was measured and comparisons were made between nylon and polyethylene, the use of crimps compared to knots, and the use of a mechanical distractor compared to hand tightening techniques. A value of p <0.05 was considered significant.

RESULTS

Fifty-eight veterinarians created 72 lateral suture constructs. Final tensions generated ranged from 1.4-171.0N. The median tension of nylon sutures (43.9N ± 44.7N) was significantly greater than polyethylene sutures (9.5 N ± 19.6N). The median tension of constructs secured with crimps (62.8N ± 42.4N) was significantly greater than constructs secured with knots (11.8 N ± 14.8N). The mechanical distractor generated significantly higher median tension (78N ± 50.4N), compared to methods without the device (18.6 N ± 25.1N).

CLINICAL SIGNIFICANCE

There was a large variability in the tension generated in simulated lateral fabellotibial constructs. Veterinarians who used nylon, crimps, and the mechanical tensioner generated constructs with greater tensions.