Biomechanics of tibial plateau leveling of the canine cruciate-deficient stifle joint: a theoretical model

OBJECTIVE: To evaluate the effect of tibial plateau leveling on the biomechanics of the canine stifle. STUDY DESIGN: Analysis of a 3-dimensional (3-D) anatomically accurate theoretical model of the canine stifle. METHODS: A 3-D, 3-segment mathematical model of the normal canine stifle was modified to simulate the effect of rotation of the tibial plateau during tibial plateau leveling osteotomy (TPLO). The model examined the normal stifle, the stifle with a tibial plateau angle (TPA) of 0 degrees, and the stifle with a TPA of 5 degrees. Analysis of the models at 10 consecutive equally spaced positions during the stance phase yielded data such as ligament forces and joint reaction forces at each position. RESULTS: Rotation of the tibial plateau to a TPA of 0 degrees almost eliminates forces in the cranial cruciate ligament (CCL) throughout the stance phase. Rotation to a TPA of 5 degrees did not, however, substantially decrease the load in the CCL. Both procedures increased the load in the caudal cruciate ligament (CaCL). CONCLUSIONS: Cranial tibial thrust (CTT) is converted into caudal tibial thrust when the TPA is 0 degrees ; however, rotating the plateau to a TPA of 5 degrees does not eliminate the CTT. CLINICAL RELEVANCE: The TPLO procedure performed as currently recommended (rotating the tibial plateau to a TPA of 5 degrees) may not eliminate the CTT, but only reduce it. Both TPLO procedures evaluated here were found to increase the load in the CaCL.     

Effect of 9 mm tibial tuberosity advancement on cranial tibial translation in the canine cranial cruciate ligament-deficient stifle

Objective— To assess the effect of 9 mm tibial tuberosity advancement (TTA) on cranial tibial translation (CTT) in a cranial cruciate ligament (CCL)-deficient canine stifle model.
Study Design— In vitro cadaveric study.
Animals— Canine pelvic limbs (n=12).
Methods— Each stifle was placed in a jig at 135° with a simulated quadriceps force and tibial axial force. CTT distance was measured with the CCL intact (iCCL), transected (tCCL), and after performing TTA using a 9 mm cage.
Results— Mean CTT for iCCL was 0.42 mm, 1.58 mm after severing the CCL, and 1.06 mm post-TTA. The tCCL CTT measured without any quadriceps force was 2.59 mm. Differences between the intact and tCCL ( P <.0001) and tCCL and TTA ( P =.0003) were significant. The difference between the tCCL with and without the quadriceps force was not significant ( P =.0597).
Conclusions— These data confirm that TTA does reduce CTT in tCCL stifles in this model. The CTT noted was less than that noted clinically. The addition of a simulated quadriceps force to a CCL-deficient stifle before a TTA, by itself, may not significantly lessen CTT.
Clinical Relevance— Whereas this in vitro model demonstrated that TTA reduced CTT in canine stifles with CCL transected, the model limitations preclude extrapolation to the effect of TTA in a live dog.     

Effect of tibial tuberosity advancement on cranial tibial subluxation in canine cranial cruciate-deficient stifle joints: an in vitro experimental study

OBJECTIVE: To evaluate the effect of tibial tuberosity advancement (TTA) on tibiofemoral shear force as reflected by measurement of cranial tibial subluxation (CTS) and patella tendon angle (PTA) in the canine cranial cruciate ligament (CrCL) deficient stifle joint. STUDY DESIGN: In vitro cadaver study. ANIMALS: Canine cadaveric hind limbs (n=10). METHODS: CTS and PTA were evaluated from lateral radiographic projections in axially loaded intact CrCL stifle joints, after transection of the CrCL, at a maximally advanced tibial tuberosity position, and at a critical point position. A custom-designed hinge plate allowed alteration of the tibia to tibial tuberosity distance (Ti-TT) under axial load. Digitized radiographic images were used to quantify CTS, PTA, and Ti-TT. Comparisons within groups were made using 1-way repeated measures ANOVA. A post hoc Tukey's HSD test was used to determine post-ANOVA pair-wise comparison within these groups. Significance was set at a value of P<.05. RESULTS: CTS occurred after CrCL transection, which was significantly different from the intact position (P<.01). Subsequent stability of the stifle joint was obtained by advancing the tibial tuberosity. In the maximally advanced tibial tuberosity position, caudal tibial thrust was generated resulting in caudal tibial subluxation that was significantly different from the transected CrCL position (P<.01) and from the intact CrCL position (P<.01). Despite a stable joint, there was slight CTS at the critical point position, which was significantly different from the intact CrCL position (P<.05). The PTA at the maximally advanced position was significantly different from the intact, critical point and reference 90 degrees PTAs (P<.01). The PTA at the critical point position was significantly different from the intact and maximally advanced tibial tuberosity PTAs (P<.01), but not different (P>.05) from the reference 90 degrees PTA. CONCLUSION: We demonstrated that advancement of the tibial tuberosity neutralized cranial tibial thrust, and converted cranial tibial thrust into caudal tibial thrust. Neutralization of tibiofemoral shear forces occurred at a PTA of 90.3+/-9.0 degrees. CLINICAL RELEVANCE: TTA can effectively change the magnitude and direction of the tibiofemoral shear force, and thus may be used to prevent craniotibial translation in a CrCL deficient stifle joint.     

Arthroscopy of the canine stifle

Arthroscopy is presented as a safe, non-invasive diagnostic technique in dogs with knee-joint lesions. Equipment, procedure, and indications are briefly described. Advantages and disadvantages are summarized.     

Arthroscopy of the canine stifle

Summary

Athroscopy is presented as a safe, non‐invasive diagnostic technique in dogs with knee‐joint lesions. Equipment, procedure, and indications are briefly described. Advantages and disadvantages are summarized.     

Effect of tibial plateau leveling on stability of the canine cranial cruciate-deficient stifle joint: an in vitro study

OBJECTIVE: To evaluate the effect of tibial plateau leveling on joint motion in canine stifle joints in which the cranial cruciate ligament (CCL) had been severed. STUDY DESIGN: In vitro cadaver study. ANIMALS: Six canine cadaver hind legs. METHODS: Radiographs of the stifle joints were made to evaluate the tibial plateau angle with respect to the long axis of the tibia. The specimens were mounted in a custom-made testing device to measure cranio-caudal translation of the tibia with respect to the femur. An axial load was applied to the tibia, and its position was recorded in the normal stifle, after transection of the CCL, and after tibial plateau leveling. Further, the amount of caudal tibial thrust was measured in the tibial plateau leveled specimen while series of eight linearly increasing axial tibial loads were applied. RESULTS: Transection of the CCL resulted in cranial tibial translation when axial tibial load was applied. After tibial plateau leveling, axial loading resulted in caudal translation of the tibia. Increasing axial tibial load caused a linear increase in caudal tibial thrust in all tibial plateau-leveled specimens. CONCLUSIONS: After tibial plateau leveling, axial tibial load generates caudal tibial thrust, which increases if additional axial load is applied. CLINICAL RELEVANCE: Tibial plateau leveling osteotomy may prevent cranial translation during weight bearing in dogs with CCL rupture by converting axial load into caudal tibial thrust. The amount of caudal tibial thrust seems to be proportional to the amount of weight bearing.     

Surgical treatment of canine stifle disruption using a novel extracapsular articulated stifle stabilizing implant

A 5-year-old Labrador retriever mixed breed dog was presented for an acute non-weight-bearing left hind limb lameness. A stifle disruption was diagnosed. The patient was treated using a novel extracapsular articulated stifle stabilizing implant (Simitri™). Twelve weeks after surgery the patient had full range of motion of the affected stifle and had begun to return to pre-injury activity. This is the first reported case of this condition being surgically managed successfully in this manner.     

Arthritis of the canine stifle joint.

A survey of cadaver material was undertaken in order to determine the prevalence of arthritis of the canine stifle joint. One hundred and fifty unselected cadavers were obtained from veterinary practices for this purpose, and their stifle joints were radiographed and dissected to discover abnormalities. Thirty-one dogs (20 per cent) had stifle arthritis and in all except one the lesions were characteristic of osteoarthritis. In the exceptional case infection was the cause. A mechanical derangement was present in 20 of the 54 affected joints, in the form of rupture of the anterior cruciate ligament (10), meniscal tears (9) and patellar dislocation (1). The cause of the arthritis in the other 33 joints is unknown.     

Osteochondritis dissecans of the canine stifle joint

In fourteen dogs with osteochondritis dissecans of the stifle joint the lesion was found in the articular cartilage of the medial condyle of the femur in six and the lateral condyle in eight. Both stifle joints were affected in eight dogs and in two of these, both Wolfhounds, the shoulder joints were also affected. Ten dogs were treated surgically and three by conservative means. The results of treatment are discussed.     

Evaluation of the triple tibial osteotomy. A new technique for the management of the canine cruciate-deficient stifle.

The triple tibial osteotomy (TTO) is a technique which combines the features of tibial tuberosity advancement and wedge osteotomy for the treatment of complete and partial cruciate ligament injuries in dogs. In this paper, the technique is described and the results of a prospective study of 64 consecutive cases are presented. TTO provided a satisfactory clinical outcome in a very high percentage of cases. The technique is relatively easy to learn and has a low post-operative complication rate.     

Multiple ligamentous injuries of the canine stifle joint: a study of 12 cases

Multiple ligamentous injuries of the canine stifle are uncommon. In this study, they affected mainly adult, male, working or sporting dogs and occurred secondary to severe trauma, or where chronic joint infection had weakened the supporting structures. Rupture of the cranial cruciate, caudal cruciate and lateral collateral ligaments was the most common injury observed and this occurred after catching the limb in a fence or gate. Reconstruction of the collateral and cranial cruciate ligaments, and careful repair of damaged menisci and joint capsule, was an effective method of treatment for medium- and large-size dogs. Reconstruction of the caudal cruciate ligament and postoperative limb support was not found to be essential. All dogs with subluxated stifles had good to excellent limb function with minimal loss of mid-thigh circumference or stifle joint range of motion at follow-up. Less favourable results were achieved where there was stifle joint luxation with extensive disruption to secondary joint restraints.     

Association of meniscal injury to joint space width on standard tibial plateau leveling osteotomy lateral radiographic projections of the canine stifle

Up to 70% of dogs with cranial cruciate ligament tears have concurrent meniscal injury, and these injuries can increase the risk of developing osteoarthritis and persistent lameness. Studies assessing joint space width on knee radiographs in people have indicated associations between joint space width and meniscal injuries. The aim of this prospective analytical study was to determine if there was an association between stifle joint space width on three different radiographic projections (the standard tibial plateau leveling osteotomy projections and a standing lateral projection) and meniscal injuries identified at surgery in dogs. There was a significant association between dogs with a meniscal tear and the corresponding joint space width on standard tibial plateau leveling osteotomy lateral radiographic projections (P‐value = .0028). Based on receiver operator characteristic curve analysis, joint space widths measuring less than 3.43 mm may indicate a meniscal tear, with a corresponding 89.5% specificity and 40.5% sensitivity in dogs weighing 31 kg. Joint space narrowing is seen with meniscal tears in dogs, and radiography may be a noninvasive way to identify meniscal tears prior to surgery.     

Radiographic features of a lateral extracapsular wire suture in the canine cranial cruciate deficient stifle

Radiographs of 74 dogs (84 stifles) presented with a cranial cruciate ligament rupture and surgically treated using a lateral extracapsular wire (LEW) were reviewed. A strand of orthopaedic wire was surgically placed caudally around the lateral fabella and through a predrilled hole in the tibial crest. At six week follow-up, the LEW was broken at least once in 26 of 33 stifles, predominantly in the area of the lateral fabella. In five stifles, the LEW had slipped off the fabella and was displaced distally along the gastrocnemius muscle. Six months after surgery, the LEW was often broken at several sites. LEW migration was rare. Osteolysis and sclerosis at the site of LEW penetration through the tibial crest occurred in about two-thirds of the stifles examined.     

Location of the instantaneous center of joint rotation in the normal canine stifle

Locations of 3 instantaneous centers of joint rotation (ICR) were found in the stifles of 6 healthy dogs. A novel algorithm, verified by computer simulation, was used to determine ICR from radiographs. Comparisons of ICR locations were made between flexion and extension, between left and right limbs, and between living and dead dogs, using analysis of variance. All stifles were examined for evidence of lesions, but all were normal. The normal location of the ICR in the stifle is near the joint surface, indicating that there is a predominantly rolling type of motion. As the limb flexes, the ICR moves caudally; as the limb extends, the ICR moves cranially. Significant differences in ICR position were not found between left and right limbs or between living and dead dogs. The average ICR position was significantly more caudal during extension than it was during flexion. Knowing the normal ICR position is a preliminary to diagnosing joint abnormalities, using the ICR.     

Changes in the canine stifle joint following rupture of the anterior cruciate ligament

Sixty–four dogs with rupture of the anterior cruciate ligament in one or both stifle joints were referred to the Royal Veterinary College, London for treatment. Details of the pathological changes in the joints were recorded at the time of open surgery in fifty–seven and these changes are discussed. A post–mortem examination was made on one dog and the joint lesions were studied more closely.     

The canine stifle joint II. Medial luxation of the patella

A method of assessment of cases of medial luxation of the patella for deciding the type of surgical intervention is described. The results of treatment of the cases after such an assessment indicate that, if there is no gross distortion and no deviation of the tibial tuberosity, simple lateral capsular overlap gives a satisfactory return of function, even in cases of irreducible patellar luxation.
Résumé. Les auteurs décrivent une méthode propre à évaluer les luxations médiales de la rotule en vue de déterminer la nature de l'intervention chirurgicale à pratiquer. Les résultats thérapeu-tiques obtenus sur la base de cette évaluation portent à conclure que, sauf grave déformation ou déviation de la tubérosité du tibia, le simple chevauchement capsulaire latéral permet de rétablir un état fonctionnel satisfaisant, měme dans les cas de luxation rotulaire irréductible.
Zusammenfassung. Es wird eine Methode zur klinischen Beurteilung von Fällen einer medialen Luxation der Patella zwecks Entscheidung über die Art des erforderlichen chirurgischen Eingriffs beschrieben. Die Behandlungsergebnisse in den Fällen nach einer solchen Beurteilung zeigen, dass beim Fehlen einer makroskopischen Verformung und einer Abweichung der Tuberositas tibiae die einfache laterale Kapselüberlappung eine zufriedenstellende Rückkehr der Funktion selbst in Fällen nicht reduzierbarer patellarer Luxation ergibt.     

The effect of stifle angle on cranial tibial translation following tibial plateau leveling osteotomy: an in vitro experimental analysis

This study was designed to determine the ability of tibial plateau leveling osteotomy (TPLO) to eliminate cranial tibial translation (CTT) through a loaded range of motion. Twenty-four large-breed canine cadaver limbs were compared. Each limb was placed in a custom designed jig at 120° of stifle extension under an axial load of 20% body weight. A force of approximately 10 N/s mimiced the action of the quadriceps muscle and allowed the limb to move from 120° to maximal extension. Positional data were acquired using electromagnetic motion-tracking sensors. Each limb was tested under normal, cranial cruciate ligament (CrCL)-deficient, and TPLO-treated conditions. Cranial tibial translation significantly increased after transection of the CrCL. The TPLO failed to normalize CTT within the CrCL deficient stifle; however, values trended towards intact values throughout the range of motion. The TPLO was more effective at higher angles of flexion. These altered biomechanics may help explain the continued progression of osteoarthritis in TPLO repaired stifles. This loaded model may serve as a method for future evaluation of other surgical techniques.     

The surgical significance of the blood supply of the canine stifle joint

The blood supply of the stifle joint was investigated in ten fresh dog cadavers using injections of Micropaque into the aorta and subsequent radiographic examination. The relevance of the blood supply to surgical intervention and the repair of injuries is discussed.