A Review of Extra-Articular Prosthetic Stabilization of the Cranial Cruciate Ligament-Deficient Stifle C

Review Article © Schattauer 2011 167 A review of extra-articular prosthetic stabilization of the cranial cruciate ligament-deficient stifle C. A. Tonks; D. D. Lewis; A. Pozzi University of Florida, Comparative Orthopaedics Biomechanics Laboratory, Department of Small Animal Clinical Sciences, Gainesville, Florida, USA Introduction (17, 18). The screw-home mechanism is a Keywords term used to describe the cranial (gliding) Cranial cruciate ligament, extra-articular, Cranial cruciate ligament (CrCL) insuffi- and external rotation (sliding) motion the lateral circumfabellar-tibial suture ciency is a common cause of hindlimb tibia undergoes relative to the femur as the Summary lameness in dogs that can precipitate me- stifle is extended (19). This phenomenon, Extra-articular prosthetic stabilization tech- niscal injury and inevitably incites osteoar- which has been comprehensively described niques have been used as a method of stabi- thritis (OA) of the stifle (1, 2). Adult, large in the human knee, is also thought to occur lization of the cranial cruciate ligament breed dogs are most frequently affected by in the dog’s stifle (17–21). (CrCL)-deficient stifle for decades. During CrCL insufficiency with Rottweilers, New- Multiple studies have evaluated the ef- foundlands, and American Staffordshire fects of CrCL insufficiency on stifle bio- extra-articular prosthetic stabilization, the prosthesis is anchored to the femur and Terriers being over represented breeds mechanics, kinematics, and gait (21–25). (3–5). Although the risk for CrCL insuffi- Cranial cruciate ligament deficiency alters tibia, and tensioned in the attempt to resolve femorotibial instability. The position of the ciency increases with age,many large breed stifle and hindlimb kinematics resulting in anchor points of the prosthesis is crucial for dogs sustain CrCL insufficiency in young cranial tibial translation, increased internal restoring a normal range of joint motion and adulthood (3–5). Cranial cruciate ligament rotation and adduction of the tibia es- mitigating alterations in prosthesis tension insufficiency in dogs is most commonly pecially during the stance phase of the gait due to progressive, mid-substance, patho- cycle (22, 23). Gait and kinematics analysis during motion. Recently developed techniques offer several innovations with poten- logical ligamentous failure (6).Despite nu- of dogs with unilateral transection of the tial advantages such as bone-to-bone fix- merous investigations, the aetiopathogen- CrCL did not reveal any improvement in ation, prosthetic materials with better mech- esis of CrCL insufficiency in dogs remains cranial tibial translation or coronal plane unknown (7–13). Dogs with unilateral instability over a two-year study period anical properties, and improved isometry of the anchor points. Whether these inno- CrCL insufficiency have a 37% incidence of (23). The kinematic changes that occur in vations provide clinically superior results to developing CrCL insufficiency in the the CrCL-deficient stifle alter loading of the the traditional techniques such as lateral contralateral stifle within a year of the in- articular cartilage and this has been postu- circumfabellar-tibial suture techniques has itial diagnosis of the initial ligament failure lated to be an initiating factor in the devel- yet to be determined. (14). Cranial cruciate ligament insufficien- opment of OA (22–24, 26). Studies map- cy can also occur as a result of a traumatic ping articular contact pressures and dis- injury, but traumatic CrCL rupture is less tribution have shown alterations in peak Correspondence to: common and typically unilateral (15). and mean pressures as well as in contact Dr. Antonio Pozzi, DMV, MS, Diplomate ACVS The CrCL has a complex structure and is area in cadaveric stifles following CrCL Department of Small Animal Clinical Sciences composed of fibre bundles organized into transection (27–29). In addition, abnormal College of Veterinary Medicine two distinct bands: the smaller cranio- kinematics alter surface velocity and in- University of Florida PO Box 100126 medial band which remains taut in both ex- crease the plowing friction, which has been Gainesville, Florida 32610 tension and flexion, and the larger caudo- recently proposed as another mechanism United States lateral band which is taut in extension and to explain the relationship between abnor- Phone: +1 352 392 2226 lax in flexion (6, 16, 17). The CrCL func- mal articular surface interaction and the Fax: +1 352 392 6125 E-Mail: [email protected] tions to stabilize the stifle by preventing hy- development and progression of OA (21). perextension, cranial tibial translation, and Restoration of normal stifle kinematics and Vet Comp Orthop Traumatol 2011; 24: 167–177 doi:10.3415/VCOT-10-06-0084 excessive internal tibial rotation (16). The contact mechanics should be a primary ob- Received: June 3, 2010 CrCL also guides the stifle through its glid- jective of CrCL insufficiency treatment Accepted: December 22, 2010 ing and sliding motion, which is classically (25). The multiplanar motion of the stifle Pre-published online: March 3, 2011 described as the screw-home mechanism coupled with the complex structure and Vet Comp Orthop Traumatol 3/2011 168 C. Tonks et al.: Extra-articular prosthetic stabilization function of the CrCL, make optimal treat- cient stifle in dogs and to offer some per- technique, but in essence, it was the first ment of CrCL insufficiency problematic spective as to the rationale behind the effi- true circumfabellar technique (42). Flo’s and challenging (16, 19, 30). cacy of these described techniques. modified retinacular imbrication tech- Dogs suffering from CrCL insufficiency nique involved placement of both medial can be managed either with or without sur- and lateral circumfabellar-tibial sutures gery. Non-surgical management involves History (42). The sutures were anchored around activity modification, body weight man- the fabellae in the gastrocnemius muscles agement, and administration of analgesic The original extra-articular prosthetic stabi- and passed through a hole drilled in the ti- and anti-inflammatory drugs (31). Non- lization procedure described by Childers bial tuberosity (42). Securing the prosthesis surgical management can result in im- was a lateral retinaculum imbrication tech- in the proximal tibia was a novel concept, as provement of lameness in some dogs (31). nique performed by placing a series of catgut all previous techniques described using the In one study evaluating the efficacy of non- sutures in a Lembert pattern in the lateral patellar tendon as the cranial suture an- surgical management of dogs with CrCL fascia of the stifle (38). Pearson modified this chorage point. The location of the hole in insufficiency, 83% of dogs weighing less technique by adding a second layer of Lem- the tibial tuberosity was described as 6 mm than 15 kg had improvement of lameness; bert sutures to the lateral fascia as well as a distal to the proximal insertion point of the whereas, lameness improved in only 13% of series of medial imbrication sutures (39). patellar tendon and 6 mm caudal to the dogs weighing greater than 15 kg (31). Pearson advocated using heat-sterilized cranial surface of the tibial tubercle (42). An array of surgical techniques intend- medium-weight, synthetic, non-absorbable The stability afforded by the circumfabellar ed to address CrCL insufficiency have been suture material (39). An experimental study sutures was augmented by a suture placed described including intra-articular stabili- comparing Pearson’s extra-articular stabili- through the lateral fabellar fascia and then zation, extra-articular stabilization, and ti- zation technique and Paatsama’s intra-ar- passed just lateral to the patella to act as an bial osteotomy techniques (32–60). Intra- ticular stabilization technique found better imbrication suture (42). articular stabilization techniques utilize clinical and post-mortem results with the Six years later, Gambardella et al. pro- autografts, allografts, xenografts, and syn- extra-articular stabilization technique (32, posed a circumfabellar technique that in- thetic materials to replace the incompetent 39, 62). In 1970, a major advancement was cluded one lateral circumfabellar suture and CrCL (32–37). Extra-articular stabilization made by DeAngelis and Lau with the publi- two sutures placed through the lateral collat- techniques are predicated on transiently re- cation of the description of extra-articular eral ligament with all three sutures passing straining abnormal stifle motion until suf- stabilization by the placement of two Da- through the patellar tendon as the cranial ficient joint adaptation occurs to provide cron sutures or stainless steel wires in the lat- anchorage points (43). In 1990, Brinker et al. functional stability and improved limb eral retinacular tissues immediately caudo- described a modification of Flo’s technique, function (44). Tibial osteotomy techniques proximal to the fabella in the lateral head of called the three-in-one technique, in which alter tibial, and therefore stifle, con- the gastrocnemius muscle (40). The sutures medial and lateral circumfabellar sutures formation to restore functional stability to were also placed through the lateral third of were placed as Flo had described with the ex- the CrCL-deficient stifle (53–59). the patellar tendon just proximal to the in- ception that medial and lateral fascial imbri- Two categories of extra-articular stabili- sertion on the

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