Volume 50 | Issue 1 Article 7

1988 Stifle njurI ies in the Canine Jadid Johnson Iowa State University

Robert Radasch Iowa State University

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Recommended Citation Johnson, Jadid and Radasch, Robert (1988) "Stifle nI juries in the Canine," Iowa State University Veterinarian: Vol. 50 : Iss. 1 , Article 7. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol50/iss1/7

This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Stifle Injuries in the Canine

Jadid Johnson, BS * Robert Radasch, DVM **

Introduction observation, palpation of the affected stifle may Stifle injuries are the most common cause for rear begin. The joint is gently flexed and extended sever­ limb lameness in the adult dog. The recognition al times with the palm ofone hand over the crani­ and treatment ofthese injuries is an imponant pan al aspect ofthe joint to detect crepitation, grating, of any small animal pra~tice. This anicle will dis­ clicking, or snapping. The areas lateral to the troch­ cuss the diagnosis and various methods for repair lear ridges are palpated for smoothness or rough­ of stifle disorders. ness. Ifthe condyles appear thick or rough, this may 4 Cruciate ligament injuries are the most common indicate the presence of osteophytes. lesion in the stifle joint of the dog. Although the Cruciate Ligament Abnormalities cranial cruciate ligament is most often injured, rup­ Drawer movement, defined as craniocaudal in­ ture of either the cranial or caudal cruciate results stability of the stifle, is indicative of cruciate in instability and predisposes the joint to degener­ ligament abnormalities. Except in young puppies, ative changes.! Meniscal injury usually occurs with there is no drawer movement in normal dogs. Even panial or complete tearing ofthe cranial or caudal the slightest amount indicates some form ofpathol­ 2 cruciates. Injuries to the collateral ligaments ofthe ogyexists.4 To palpate for drawer movement, the stifle are not common. The most common injury examiner stands caudal to the animal which is involves the medial collateral ligament and is usual­ positioned in lateral recumbency with the stifle ly seen in conjunction with cranial cruciate ligament opposite the one to be palpated closest to the table. rupture and damaged medial meniscus. This trilogy The index fmger ofone hand is placed on the prox­ of knee injuries is called the "unhappy triad".3 imal end of the patella while the thumb is placed When both collateral ligaments are ruptured, both over the lateral fabellar region. The index finger of cruciates are ruptured also and the diagnosis is one the other hand is placed on the tibial crest and the of a "total knee".3 Traumatic patellar luxation is thumb is positioned caudal to the fibular head. The a relatively rare injury and is almost always a medial leg is flexed slightly and the femur held steady while luxation.! Patellar fractures and patellar ligament the tibia is pushed cranially and caudially. Drawer ruptures are also rarely encountered in the dog. 1 motion should be tested in both extension and flex­ ion. Caudal drawer movement is often difficult to Diagnosis distinguish from cranial drawer. However, a sud­ Veterinarians often encounter patients with a his­ den cessation of cranial drawer movement occurs tory of lameness or pain of unknown origin. In a when an intact cranial cruciate becomes taut. With hospital environment, excitement and apprehen­ cranial cruciate rupture, the cessation is not abrupt.4 sion often seem to cause a chronic lameness to disappear or painful maneuvers to go unnoticed. Memscal Injury History, observation, palpation and proper radio­ graphy are all imponant in assessing the patient. Meniscal injuries are best diagnosed by direct in­ One of the first tasks is to walk and trot the spection ofthe joint. However, a pathologic menis­ animal observing any gait abnormalities. If lame­ cus may be suspected ifa meniscal click is palpated ness is not apparent, having the animal gait in tight or heard during flexion or extension and drawer circles may elucidate abnormalities. After gait manipulations of the stifle. 5

*Dr. Johnson is a 1987 graduate of the College of Veterinary Medicine at Iowa State University. Collateral Ligament Instability **Dr. Radasch is an adjunct instructor in the Department of Veterinary Clinical Sciences at Iowa State University. To test for collateral ligament insufficiency, the 16 The Veten'nary Student limb is held in extension and varus and valgus posterior displacement of the tibia on the femur stresses are applied to the joint. In the case ofmedial (posterior drawer). collateral ligament rupture, the medial aspect ofthe In general, the bulk of the cranial cruciate liga­ joint will open when a valgus stress is applied. With ment is tight in extension and loose in flexion, while lateral collateral ligament rupture, the lateral aspect the bulk of the caudal cruciate is loose in exten­ ofthe joint will open when a varus stress is applied. 3 sion and tight in flexion. 6 Because the cranial cru­ ciate ligament is tight in extension it is the primary The Cruciate Ligaments check against hyperextension of the stifle. As stated previously, cruciate ligament injuries are the most common lesion in the stifle joint of Mechanism Of Injury the dog. The cruciate ligaments play an imponant As mentioned, the cranial cruciate ligament pre­ role in maintaining the stability ofthe stifle through vents anterior displacement of the tibia on the the functional range ofmotion. Rupture ofone or femur, limits internal rotation of the tibia on the both cruciates results in severe instability and pre­ femur, and prevents hyperextension of the stifle. disposes the joint to degenerative changes. The The most common mechanism of injury of the cruciate ligaments are dynamic structures and their cranial cruciate ligament is sudden rotation of the anatomy and spatial relationship are directly relat­ stifle with the joint in 20 to 50 degrees offlexion. l ed to their function as constraints ofjoint motion. 1 As the cranial cruciate ligament tries to limit In order to understand the mechanism of injury internal rotation of the tibia, it becomes wound and rationale behind repair techniques, it is neces­ excessively tight and is subject to trauma from the sary to understand their anatomy and function in lateral femoral condyle. Clinically, this injury occurs relation to joint motion. when an animal makes a sudden turn on the weight-bearing rear limb. Anatomy and Function With hyperextension ofthe stifle, the cranial cru­ The cranial cruciate ligament is attached to a fossa ciate ligament is the first structure subject to injury. on the posterior aspect of the medial side of the This type ofinjury occurs when an animal steps into lateral femoral condyle. It courses cranially, medi­ a hole while running. Extreme hyperextension of ally and distally across the intercondylar fossa and the stifle damages the caudal cruciate only secondary attaches to the cranial intercondyloid area of the to rupture of the cranial cruciate ligament. tibia. The caudal cruciate ligament is attached to Rupture ofthe caudal cruciate ligament alone is a fossa on the ventral aspect of the lateral side of rare and is usually associated with severe trauma or the medial femoral condyle. It passes caudodistally dislocation ofthe stifle. 1 Direct trauma ofthe tibia to the medial aspect of the popliteal notch of the is an anteroposterior direction may cause the caudal tibia. The caudal cruciate ligament lies medial to cruciate ligament to rupture. Also, persistant stifle and crosses the cranial cruciate ligament. During instability due to other ligament damage may lead flexion, the ligaments twist on each other. rupture of the caudal cruciate ligament. As the stifle is flexed, the femoral and fibular attachments ofthe lateral collateral ligaments move closer together and the ligament begins to relax. Cruciate Ligament Repair This allows posterior displacement of the lateral It has been established that rupture of either femoral condyle on the tibial plateau and results cruciate ligament results in joint instability which in internal rotation of the tibia on the femur. 1 leads to progressive degenerative changes within the Conversely, as the knee is extended the lateral col­ joint. It is for this reason that cruciate ligament lateral ligament tightens and the lateral femoral injuries should be repaired. Through the years there condyle moves anteriorly causing external rotation have been many developments in the surgical repair ofthe tibia. 1 The twisting ofthe cruciate ligaments ofthe cruciate ligaments. Although there are many during flexion limits the amount of internal rota­ repair techniques currently in use, the method tion of the tibia. If either cruciate ligament chosen depends on surgeon preference and techni­ ruptures, there will be an abnormal increase in the cal ability. Surgical techniques can be divided into amount of internal rotation. two basic categories; intraarticular and extraarticular The primary function of the cruciate ligaments procedures. Intraanicular techniques utilize either is to maintain anteroposterior stability ofthe stifle. autogenous or synthetic graft material to replace the The cranial cruciate ligament limits forward dis­ cruciate ligament. Extraanicular techniques stabi­ placement of the tibia on the femur (anterior lize the joint by tightening extraarticular structures. drawer) while the caudal cruciate ligament limits Regardless ofthe method chosen, the joint should

Vol. 50, No. 1 17 be opened so that the torn ends of the ligament suture is pre-placed around the fabella and through can be removed and the menisci examined. In all a hole in the tibial crest. The lateral suture is tight­ methods or repair, the limb is post operatively ened first to externally rotate the tibia to limit placed in a modified Robert-Jones bandage and internal rotation. The medial suture is then tight­ protected from stress for two weeks. ened. Together, the two sutures act as a sling to prevent anterior drawer motion. Extraarticular Repairs Although there are many techniques for extra­ Posterior Capsulorrhaphyl articular repair, the basic principle is the same. The The posterior capsulorrhaphy technique provides lateral joint tissues are tightened in an antero­ both medial and lateral support to the stifle. posterior direction in order to eliminate drawer Following a medial anhrotomy, the joint is explored movement. This is usually accomplished by plac­ and the capsule closed routinely. The posterior ing imbrication sutures on the lateral aspect ofthe sanorius muscle is transected at its insertion and joint which also decreases the tendency for internal advanced to the proximal aspect ofthe patellar ten­ rotation of the tibia. don where it is sutured with absorbable suture material. The lateral aspect of the joint is then Capsular Imbrication approached and the joint capsule identified. A This technique, developed in 1966 by Childers small incision is made in the posterolateral joint cap­ uses multiple Lembert sutures placed 5 mm apart sule parallel to the joint line. This incision is closed in the lateral joint capsule. The sutures are tight­ with two imbrication mattress sutures. Next the ened with the limb in extension which creates a biceps tendon and fascia lata are plicated over the longitudinal fold in the lateral parapatellar area. If patellar tendon with interrupted sutures that are anterior drawer is still present an additional layer tied while the joint is in extension. Thus, the ofLambert sutures is placed over the original one. posterolateral joint capsule is tightened to limit This procedure tightens the joint capsule in an rotational instability. Anteroposterior instability anteroposterior direction to eliminate drawer and is checked by the medial and lateral muscle internal rotation of the tibia. This technique is advancements. reported to work well in cats and smaller dogs. Fibular Head Transposition1o Lateral Suture TechniqueS This technique involves moving the fibular head into a cranial position which alters the orientation This procedure utilizes a standard lateral ofthe lateral collateral ligament to prevent cranial approach to the stifle. An arthrotomy is performed drawer and minimize internal rotation ofthe tibia. to remove the torn cruciate ligament and inspect A lateral anhrotomy is used to inspect the joint for the menisci. Following closure of the arthrotomy, pathology and remove the torn ends ofthe cranial a single mattress suture of heavy (0, #1, or #2) cruciate ligament. Following closure of the joint nonabsorbable suture material is placed on the later­ capsule, the lateral retinaculum is separated from al aspect ofthe joint. The suture material is passed the joint capsule and retracted caudally to expose around the lateral fabella and then through and the attachment of the cranial tibial muscle to the back through the patellar ligament just proximal tibia and fibula. A small incision is made in the to its insertion on the tibial tuberosity. The leg is connective tissue between the peroneus longus placed in a functional position and the suture tight­ muscle and the cranial tibial muscle. The muscle ened. Ifdrawer movement is still present after place­ bellies are separated by blunt dissection. Anteriorly, ment ofthe first suture, additional sutures may be the cranial tibial muscle and long digital extensor placed parallel and as close as possible to the first tendon are bluntly elevated from the tibia using suture. If the patellar ligament is damaged and a periosteal elevator. Posteriorly, the peroneus won't suppon the imbrication suture, a drill hole longus muscle is incised at its attachment to the can be placed in the tibial crest and the suture tibia, leaving its attachment to the fibula intact. passed through it. The fibular head and attached lateral collateralliga­ ment are palpated. A scalpel is used to incise the Modification ofthe Lateral Retinacu1ar hnbrication9 cranial and caudal fibular ligaments completely A modification of the lateral retinacular imbri­ freeing the fibula from the tibia. cation technique involves the use of a single Two holes are drilled in the tibial crest cranial imbrication suture placed on the medial as well as to the fibular head. A loop of 18 gauge orthopedic lateral aspect of the joint. In this technique, each wire is passed through the holes such that the ends

18 The Veterinary Student of the wire emerge laterally from beneath the graft is cut transversely and the graft dissected free craniolateral tibial musculature. A Steinmann pin from underlying tissues. It remains attached distally. is directed through the caudal half of the fibular A 5/32 to 3/16 inch hole is drilled transversely head and the fibula transposed cranially with the through the tibial tubercle near the tibial plateau. tibia in full external rotation. With the stifle in a The proximal end of the facial strip is passed neutral position the pin is seated into the tibia. The through the hole so that the graft is transferred to wire is looped around the pin in a figure 8 and the medial side of the tibia. The graft is pulled into tightened sufficiently to eliminate cranial drawer the medial anhrotomy through the fat pad into the and minimize internal tibial rotation. The lateral joint. retinaculum is closed using a vertical vest-over-pants Lateral to the joint, the biceps is retracted to imbrication. This technique is reponed to give per­ expose the lateral fabella. A curved hemostat is formance equal or superior to other techniques for inserted into the femoral-fabellar ligament, pushed reconstructing the cruciate deficient stifle. 10 forward through the caudal joint capsule into the In all instances, extraanicular procedures treat the intercondylar space. The tips of the hemostat are instability resulting from cranial cruciate ligament manipulated lateral to the caudal cruciate ligament rupture by tightening extraarticular tissues. Tight­ then cranially so they can be seen in the joint. The ening ofthe extraanicular tissues places additional graft is grasped by the hemostat and pulled cau­ constraints on normal joint motion. It is thought dally through the joint and over-the-top of the that while these constraints are well tolerated by lateral femoral condyle. With the leg in a functional smaller dogs «30 lbs), the larger dogs generate position, traction is applied to t.he gra...ft to elLrninate sufficient force to overcome these constraints. 1 This drawer movement. Once drawer is eliminated, the may explain the inconsistent results observed in graft is sutured to the tissues over the lateral femoral larger breed dogs in which extraarticular techniques condyle. have been used. 1 The medial arthrotomy is now ready to be closed. The insertion of the caudal belly of the sartorius Intraarticular Repairs is partially detached from the tibia and sutured to Intraanicular techniques for cranial cruciate the patellar ligament along with the joint capsule ligament repair involve the recreation of an intra­ and medial fascia as far proximally as the patella. articular structure in the approximate orientation From this point proximally, the sartorius is not of the normal cranial cruciate ligament. Current included in the rest of the medial closure. intraarticular techniques use fascia lata or patellar The lateral fascial incision is then closed. Because tendon grafts. Other materials have been used with a strip of fascia was removed, the biceps femoris less success. is slightly advanced and the lateral retinaculum tightened. A suture of size 2 to 4 absorbable The Four-in-One Over-the-Top Techniquell material is placed from the lateral fabella to the This technique is similar to the Over-the-Top distal patellar ligament. It is tied tightly to eliminate procedure developed by Arnoczky, however, it has any remaining drawer. This suture protects the graft been modified to be technically easier. for a few weeks. The rest of the closure is routine. A medial arthrotomy is performed to remove Four procedures have been performed to stabi­ ligament fragments and inspect the menisci. A 1 1ize the joint. Advancement ofthe caudal sartorius to 1.5 cm graft of the fascia lata is isolated from and biceps muscles to create caudal traction on the the lateral aspect ofthe joint and remains attached tibia; fabellar-patellar ligament suture to temporar­ at the junction of the patellar ligament with the ily prevent anterior drawer motion; and fascia lata tibial tubercle. The strip is fashioned by incising graft to replace the cruciate ligament. the fascia lata just lateral to the patellar ligament from the tibial tubercle extending proximally, a few Over-the-Top Technique1! millimeters lateral to the patella. The caudal edge This technique developed by Arnoczky is iden­ ofthe strip is formed by incising 1 to 1.5 cm caudal tical to the previous one except for the preparation and parallel to the first incision. Both incisions are of the graft. It can also be modified to include continued proximally using scissors such that the advancement of the caudal sartorius and biceps length of the graft is 2 1/2 to 3 times the distance muscles, and the placement of a fabellar to patel­ from the tibial tubercle to the midpatalla. Prox­ lar ligament suture. imally the caudal cut follows the cranial border of The graft is prepared by incising the patellar the biceps femoris muscle while the cranial cut is ligament longitudinally at the junction ofthe mid­ parallel to the caudal cut. The proximal end ofthe dle and medial thirds of its width from the tibial

Vol. 50, No. 1 19 tubercle to the patella. The incision is extended stifle positioned at the standing angle. Routine proximally over the patella where it is directed closure is performed and exercise severely restrict­ proximal-laterally into the fascia lata. The incision ed for three weeks, then gradually increased. proximal to the patella should be 1 to 1 112 times the ~~~ce from the patella to the tibial tuberosity. The Menisci An InCISIon parallel to the first is then made stan­ While primary injury to the menisci is rare, ing at the medial border of the patellar ligament meniscal injuries secondary to cruciate or collateral and extending proximally. The proximal end ofthe ligament rupture are common. 3 The most frequent graft is cut transversely, then dissected free from the injury involves the medial meniscus, cranial cruci­ deeper tissues distally to the patella. An osteotome ate ligament and/or the medial collateral ligament. or saw is used to remove an anteromedial wedge Meniscal damage may be acute or degenerative and of the patella with the attached graft. The rest of usually involves the posterior and medial ponions the procedure is the same as the previous one. of the medial meniscus. 3 Both ofthe "over-the-top" techniques result in a graft which almost perfectly mimics the normal Anatomy And Function ligament. The fascial strip becomes vascularized, The menisci are two semilunar fibrocanilaginous then undergoes fibroplasia and reorganization of discs that are interposed between the tibial plateau collagen to resemble a normal ligament. 11 This process takes five to six months, thus the graft is and the femoral condyles. Both menisci are attached at some risk during this time. The leg should be to the tibia by cranial and caudal ligaments. The lateral meniscus is also attached to the caudal sur­ placed in a modified Roben-Jones bandage for two weeks post-operatively. Activity should be restrict­ face ofthe femur. The medial meniscus appears to ~d to leash exercise early, then may be gradually be more immobile due to an attachment to the Increased toward the end of the healing period. medial collateral ligament. The inner or axial por­ tion ofthe menisci are essentially avascular with only Rupture Of The Caudal Cmciate Ligament the abaxial border being vascular and therefore, As discussed previously, isolated rupture of the capable of a healing response. Meniscal functions caudal cruciate ligament is rare. Most cases are due ~nclude ~rotecting anicular surfaces, relieving the to severe trauma and accompanied by rupture of 1ncong~1tybetween the femur and tibia by acting the cranial cruciate and medial collateral ligaments. as elastIC and moveable washers, and aid in lubri­ In this situation, medial meniscal injuries are com­ cation of the joint. 3 mon. Although it has been suggested that the Mechanism Of Injury caudal cruciate is not functionally significant, repairs Meniscal injury is usually secondary to cranial should be attempted because experimental sever­ cmici~te ligament rupture and only rarely diagnosed i~g of the ligament leads to degenerative joint as ~ 1solated tear. Men~scal injury has been repon­ dIsease. 11 The use ofextraanicular imbrication has ed 1? up t~ 73 o~ of stifles operated for repair of pr~ven effective ~ smaller dogs and cats. 1 No really cran1~ cruc1~te hgament rupture. ~ The instability satisfactory techn1que exists for large, active dogs. assoc1ated wlt~ rupture ofthe cranial cruciate liga­ A medial or lateral arthrotomy is combined with ment res~lts 1n abnormal compressive, shearing, an approach to the medial and lateral caudal com­ and rotat10nal forces on the meniscus. The medial partments of the stifle. ll Fragments of ligament meniscus is relatively immobile, and the caudal are excised and a meniscectomy performed when body ?~comes wedges be~een the femoral condyle indicated. The joint capsule is sutured and collateral and tlb1al plateau result1ng in either a longitudi­ ligament repairs made if needed. Nonabsorbable nal or bucket-handle tear through the caudal body.~ imbrication sutures are placed in the caudomedial Transverse me~iscal tear may occur secondary to and caudoloteral aspects of the joint capsule in a abnormal rotat10nal forces due to cranial cruciate venical fashion. ll A mattress suture of size 0-4 ligament injury. ~ Other types ofmeniscal tears have nonabsorbable material is placed in the medial half been categorized and reponed, however, they are of the proximal patellar ligament and directed ~e~s common. T~e lateral meniscus is only rarely caudodistally where it is passed around the head 1nJured because 1t is more mobile than the medial of the fibula. 11 A mattress suture is also placed meniscus. It therefore does not easily become from the lateral half of the proximal patellar liga­ trapped between the femoral condyle and tibial ment to a hole drilled through the caudomedial plateau. comer ofthe tibia. 11 These mattress sutures are tied As mentioned earlier, tentative diagnosis of tightly enough to eliminate drawer motion with the meniscal injury may be made based on preopera-

20 The Veterinary Student tive examination and the presence of a "meniscal medial collateral ligament is the prime stabilizer of click". Positive diagnosis of meniscal injury is the medial aspect ofthe joint. It acts with the cranial usually made following arthrotomy and exploration cruciate ligament and joint capsule to neutralize of the joint. valgus (lateral) angulation of the tibia. 3 The lateral collateral ligament extends from the Treatment lateral femoral epicondyle to the head ofthe fibula. There is a great deal of controversy concerning It is taut in extension but relaxes during flexion to the treatment of injured menisci. It has been allow internal rotation of the tibia. 3 The lateral demonstrated that tears of the periphery of the collateral ligament along with the popliteal tendon, meniscus, or tears extending to the periphery will cruciate ligaments, and joint capsule, serve to limit heal. 5 However, tears that are limited to the car­ varus (medial) angulation of the tibia. 3 Because tilage will not heal due to the avascular nature of there is more support to the lateral aspect of the the cartilage. joint, rupture of the lateral collateral ligament is Surgical treatment of meniscal tears consist of less common than rupture of the medial collateral either a partial or total meniscectomy. Following ligament. arthrotomy and inspection of the menisci, the en­ tire meniscus can be removed by severing the cranial Mechanism Of Injury tibial ligament, retracting the meniscus, and The collateral ligaments are strong and require separating the meniscus from the joint capsule and tremendous force to rupture. The medial collateral medial collateralligaIllent. FL.,ally, the caudal tibial ligarnent is usually ruptured with a severe valgus ligament is carefully severed.s The advantages of stress or external rotation ofthe tibia. 3 The cruciate total meniscectomy include clinical improvement, ligaments and menisci are usually also damaged the potential for regeneration of replacement tis­ with this type of force. sue, and the fact that no tears of the menisci are In young animals, avulsion fracture of the inadvertently left behind. The disadvantages appear ligamentous attachments are more common than to be the potential for degenerative joint disease rupture of the ligament, since the ligament is which has been a sequella to total meniscectomy. S stronger than its bony attachment. 3 In older Partial meniscectomy is the removal of the animals the forces may also damage bony com­ damaged portion ofa meniscus. The procedure will ponents ofthe joint. Thus, with collateral ligament vary depending on the location of the injury. The injuries, radiographs are necessary to rule out bony advantage of partial meniscectomy is that normal pathology. meniscal tissue is left in place to protect the articu­ Treatment lar canilage. Partial meniscectomy has been shown to produce less degenerative articular cartilage Complete rupture of the collateral ligaments changes than does total meniscectomy.s Disadvan­ should be repaired surgically. Although partial tears tages include the possibility of missing pathology will heal with rest and immobilization, complete ofthe meniscus, iatrogenic laceration ofthe menis­ tears rarely heal sufficiently to provide normal 3 cus, and the absence ofany regenerative changes. 3 function. Repair is directed at restoring normal function of the ligament by primary repair or The Collateral Ligaments prosthetic replacement. Damage to the collateral ligaments ofthe canine Avulsion of the collateral ligament from its stifle occur infrequently. The most common injury attachment is best treated by reattachment of the involves the medial collateral ligament and is seen avulsed ponion. In the case of a bony avulsion, a in conjunction with cranial cruciate ligament rup­ small lag screw or Kirshner wires are used to reattach ture and damaged medial meniscus. the bone fragment. 3 Ifno bone is avulsed with the ligament, the ligament can be reattached by using Anatomy and Function a screw with a spiked washer. 3 The washer allows The collateral ligaments are essential to normal for a firm grip on the ligament as it is compressed joint function. They restrain the joint to help pre­ against the bone. vent excessive movement when varus, valgus and Ruptures of the midponion of a collateralliga­ rotational stresses are applied. 3 ment can be sutured using a Bunnell or mattress The medial collateral ligament extends from the suture pattern of stainless stell of nylon. 3 Follow­ medial epicondyle of the femur to the medial ing this, bone screws are placed at the exact femoral border ofthe tibia. It remains taut throughout the or tibial origin of the ligament and a figure eight range ofmotion but is most taut in extension. 3 The pattern oforthopedic wire or Teflon-coated dacron

Vol. 50, No. 1 21 is passed around the screws and tied tight with the 3. Arnoczky SP, Tarvin GB, Vasseur P: Surgery of the Stifle - The Menisci and Collateral Ligaments (Part limb in a functional position. 3 With lateral col­ III). Compendium on Continuing Education 1980; lateral ligament rupture, the figure 8 is passed 8:394-399. around a femoral screw and through a drill hole in 4. Brinkner WO, Piermattei DL, Flo GL: Physical Exam the fibular head. It is imponant that the suture for Lameness. In: Small AnimalOrthopedics andFrac­ material is not overtightened as this may eliminate ture Treatment. Philadelphia: WB Saunders Co. 1983; 212-218. nearly all motion in the stifle. 11 5. Hulse DA, Shires PK: The Meniscus: Anatomy, Func­ Ifprimary repair ofthe collateral ligament is not tion, and Treatment. Compendium on Continuing feasible, prosthetic reconstruction in the above man­ Education 1983; 9:765-774. ner is indicated. While this will not last for a great 6. Arnoczky SP, Marshall]L: The Cruciate Ligaments of length of time, it will provide stability until scar the Canine Stifle: An anatomical and Functional Analysis. Am]. Vet Res 1977; 11:1807-1814. tissue can form and provide some suppon to the 7. Knecht CD: Evolution of Surgical Techniques for joint. 3 Cruciate Ligament Ruprure in Animals.]Am Animal In all cases ofreconstruction, the limb is immobi­ Hosp Assoc 1976; 12:717-724. lized in a Thomas splint or modified Roben-Jones 8. Gambardella PC, Wallace L], Cassidy F: Lateral Surure bandage for at least three weeks, followed by a Technique for Management of Anterior Cruciate Liga­ ment Rupture in Dogs. A Retrospective Study.]Am gradual return to full exercise. Anim Hosp Assoc 1981; 17:33-38. 9. Flo GL: Modification of the Lateral Retinacular Imbrication Technique for Stabilizing Cruciate Liga­ ment Injuries. ] Am Anim Hosp Assoc 1975; REFERENCES 11:570-576. 10. Smith GK, Torg ]S: Fibular Head Transposition for 1. Arnoczky SP: Surgery of the Stifle - The Cruciate Repair of Cruciate-Deficient Stifle in the Dog.] Am Ligaments (Part I). Compendium on Continuing Vet Med Assoc 1985; 187:375-383. Education 1980; 2:106-115. 11. Brinkner WO, Piermattei DL, Flo GL: Diagnosis and 2. Flo GL, DeYound D], Tvedten H,]ohnson L: Classi­ Treatment of Orthopedic Conditions of the Hind fication ofMeniscal Injuries in the Canine Stifle Based Limb. In: Small Animal Orthopedics and Fracture Upon Gross Pathological Appearance.] Am Anim Treatment. Philadelphia: WB Saunders Co, Hosp Assoc 1983; 19:325-334. 1983;306-325.

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22 The Veterinary Student