Extra-articular stabilization of the cranial cruciate deficient stifle with anchor systems

Comparison of Extracapsular Stabilization Techniques Using an Ultrasonically Implanted Absorbable Bone Anchor (Weldix) after Cranial Cruciate Ligament Rupture in Cats-An In Vitro Study

Simple Summary

One reason for lameness in cats is the rupture of the cranial cruciate ligament. This ligament is located in the stifle joint and contributes to its stabilization during excessive forward movement and internal rotation of the tibia. One method for the surgical treatment of cranial ligament rupture is the placement of an extracapsular suture. Different materials and methods of suture fixation have been used in dogs and cats. This study investigated the use of a novel polylactide absorbable bone anchor that was implanted with ultrasound technology for suture fixation and compared this with suture fixation alone and fixation with a nonabsorbable bone anchor using an ex vivo modified limb-press model. For evaluation, distance measurements on radiographs were performed and the angles between defined bony structures were calculated. The acquired measurements accounted for both craniocaudal and mediolateral movements, and the results showed that the absorbable anchor could neutralize excessive movement within the stifle joint in two of three measurements and seems to be a good alternative to well-known surgical methods.

Abstract

Background: This study evaluated joint stability after surgical repair of cranial cruciate ligament (CrCL)-deficient stifle joints in cats using a novel absorbable polylactide bone anchor in an ex vivo model. Methods: Thirty-six hindlimbs from cats with intact (G_i group) and transected CrCLs were treated with fabellotibial suture alone (G_FW group), suture combined with an absorbable polylactide bone anchor (G_WD group), or suture combined with a nonabsorbable bone anchor (G_FT group), positioned in a limb press with predefined joint angles (stifle joint: 120 ± 5°; hock joint: 120 ± 5°) and loaded with 10%, 20%, and 30% of body mass (BM). Predefined points were measured on lateral radiographs and with a coordinate measurement machine. Distances on radiographs (mm) were measured and angles (°) were calculated to represent the craniocaudal movement and the internal rotation of the tibia. Results: There were no differences for craniocaudal movement between G_i and G_FW or G_FT, but for G_WD regarding angle measurement at 30% BM. For internal rotation, there was no significant difference between G_i and G_FW or G_WD, but for G_FT. Conclusion: The used absorbable polylactide bone-anchor was able to stabilize the stifle joint regarding internal rotation and craniocaudal movement as calculated from distance measurements.

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.

Outcome Following Surgical Correction of Grade 4 Medial Patellar Luxation in Dogs: 47 Stifles (2001–2012)

Grade 4/4 medial patellar luxation (MPL) is a complex disease of the canine stifle that often requires surgical realignment of the patella to resolve clinical lameness. Outcome following surgery remains poorly described. Medical records were retrospectively reviewed for surgical correction of grade 4 MPL. Signalment and exam findings, surgical procedures performed, complications, and clinical outcome were reported. Data was statistically analyzed for association with major complication occurrence and unacceptable function following surgery. Forty-seven stifles from 41 dogs were included. The surgical procedures most frequently utilized for patellar realignment were the combination of femoral trochleoplasty, tibial tuberosity transposition, and joint capsule modification. Median in-hospital veterinary examination was performed at 69 days (range 30–179 days) following surgery. Full function was reported for 42.6% of cases (n=20). Acceptable function was reported for 40.4% of cases (n=19). Unacceptable function was reported for 17% of cases (n=8). The overall complication rate was 25.5% (n=12), with revision surgery for major complications required in 12.8% of cases (n=6). Corrective osteotomies were associated with major complications (P < 0.001). In general, pelvic limb function improves following surgical correction of grade 4 MPL; however, a return to full function should be considered guarded.