Lecture 7-VCS80630-2023 Stifle Part 1 PDF

DISEASES OF STIFLE PART 1 Dr. Sarah Malek VCS 80630- Small Animal Surgery Fall 2023 LEARNING OBJECTIVES • Describe the structures in the stifle joint and their contribution to stifle stability • Describe the causes, types and general pathophysiology of cranial cruciate ligament (CrCL) rupture in d...

DISEASES OF STIFLE PART 1 Dr. Sarah Malek VCS 80630- Small Animal Surgery Fall 2023 LEARNING OBJECTIVES • Describe the structures in the stifle joint and their contribution to stifle stability • Describe the causes, types and general pathophysiology of cranial cruciate ligament (CrCL) rupture in dogs • Outline the diagnostic work up and differential diagnoses for CrCL rupture • Describe the tests for evaluating stifle stability (i.e., cranial drawer and tibial thrust) and what they each test for • Outline the strategies for medical management of CrCL tear and how they compare to surgical intervention STIFLE MOTION Range of motion • Flexion-extension (~140◦) • Internal-external rotation (mild) • Valgus-varus (minimal) Stabilizers of stifle • Femoral condyles • Muscles • Ligaments • Menisci STIFLE ANATOMY LIGAMENTS Femorotibial ligaments (n=4) • • • • Cranial cruciate ligament (CrCL) Caudal cruciate ligament (CdCL) Medial collateral ligament (MCL) Lateral collateral ligament (LCL) Meniscal ligaments (n=6) • Intermeniscal (cranially) • Meniscotibial (cranial, caudal) per meniscus • Meniscofemoral (lateral meniscofemoral) Patellofemoral (n=2) • Medial and lateral Patellotibial (n=1) • Patella ligament (better known as patella tendon) STIFLE ANATOMY MENISCI Medial and lateral menisci • Fibrocartilage, C-shaped disks Both have strong tibial attachments • Medial meniscus • Attached to MCL and joint capsule • Lateral meniscus • Attachment to femur Role: Hoop stress protection • Converts compressive forces to radial forces • Radial force is resisted by circumferential fibers FUNCTION OF MENISCI Load bearing • 40-70% across the joint Load distribution/shock absorption • “Hoop stress” protection Increasing femorotibial congruity • Joint stability Damage results in partial to complete loss of function STIFLE ANATOMY LIGAMENTOUS STABILIZERS Prevent hyperextension • MCL and LCL • CrCL • CdCL Prevent hyperflexion • MCL Prevent excess varus and valgus • MCL (anti-valgus) • LCL (anti varus) • CrCL and CdCL against both Prevent cranial tibial translation • CrCL • Craniomedial(CrM) band taut in flexion and extension • Caudolateral (CdL) band taut in extension Prevent caudal tibial translation • CdCL Prevent external rotation • MCL + LCL Prevent internal rotation • MCL + LCL • CrCL+ CdCL COMMON STIFLE PATHOLOGIES • Traumatic • Fractures • Ligamentous injuries • MCL,LCL CrCL, CdCL • Meniscal injuries • Tendon injuries • Deranged stifle • Patella luxation • Non-traumatic • Degenerative CrCL rupture • Meniscal injuries • Patella luxation • Developmental disease • OC/OCD of distal femoral condyles • Angular limb deformities • Infectious • Osteomyelitis • Septic joint • Neoplastic • Osseous > non-osseous • +/- pathologic fractures • Immune-mediated arthritis CRANIAL CRUCIATE LIGAMENT DISEASE FUNCTION OF CRCL Prevent hyperextension • MCL and LCL • CrCL • CdCL Prevent hyperflexion • MCL Prevent excess varus and valgus • MCL (anti-valgus) • LCL (anti varus) • CrCL and CdCL against both Prevent cranial tibial translation • CrCL • Craniomedial(CrM) band taut in flexion and extension • Caudolateral (CdL) band taut in extension Prevent caudal tibial translation • CdCL Prevent external rotation • MCL + LCL Prevent internal rotation • MCL + LCL • CrCL+ CdCL CLINICAL SIGNIFICANCE Loss of CrCL function = joint instability • • • • Cranial translation of tibia Excessive internal rotation Excessive hyperextension Mild effect on excess valgus and varus Clinical lameness Development of osteoarthritis (OA) Financial implications • Surgical and medical costs CLASSIFICATION OF CRCL DISEASE Etiopathogenesis • Traumatic • Immature and adult patients differ • Degenerative • Most common form in adults • Progressive degeneration of unknown cause Extent of tear • Partial • Complete TRAUMATIC CRCL TEAR Immature patient • Under 12 months old • Mild to severe trauma • Excessive hyperflexion or hyperextension • Types • Avulsion fracture of CrCL insertion • Avulsion fracture of CrCL origin • Midbody ligamentous tear Mature patient • No avulsion • High impact trauma in healthy ligament • Mild to moderate trauma in degenerative ligament TRAUMATIC STIFLE INJURY Deranged stifle (stifle luxation) • Cats and dogs of any age • Traumatic • Damage to 2 or more joint stabilizers • MCL>LCL • CrCL • CdCL • Concurrent injuries • meniscal damage, patella luxation, fractures, etc. • Treatment: Stabilization of joint DEGENERATIVE CRCL TEAR PREDISPOSITION Mature dog (>4 year-old) Medium-large breed dogs Genetic predisposition Gender • Male=female • Effect of hormones debated; intact versus neutered Obesity • Mechanical and biological effects DEGENERATIVE CRCL TEAR PREDISPOSITION Joint conformation • Steep tibial plateau angle (TPA) TPA: angle between tibial plateau and line perpendicular to mechanical axis of tibia Presence of unilateral CrCL rupture • ~50% chance of tear in contralateral stifle within a year DEGENERATIVE CRCL TEAR HISTORY Severity • Acute • Chronic • Acute on chronic • Chronic on acute Lameness • Mild to severe Response to previous medical management • Variable • Incomplete resolution CRCL TEAR CLINICAL SIGNS Orthopedic examination • Lameness +/- muscle atrophy • Pain on stifle extension > flexion • +/- medial buttress • Joint fibrosis medially • Hard, non-painful • Joint effusion Cr Medial Buttress Cd No Buttress CRCL TEAR: ORTHOPEDIC EXAM Stifle stability tests • Test in both stifle flexion and extension • Isolated craniomedial band tear is missed in extension • Cranial drawer • Cranial tibial thrust Pain on extension of hip • Referred pain from extended stifle • +/- concurrent hip pathology https://veteriankey.com CRCL TEAR: ORTHOPEDIC EXAM Video available on Brightspace; Supplementary material ADDITIONAL DIAGNOSTIC TESTS? CrCL tear is a clinical or intraoperative diagnosis Radiography • OA • Exclusion of other pathologies Arthroscopy/arthrotomy • Confirmation of diagnosis and therapeutic intervention Arthrocentesis • Exclusion of other pathologies FATE OF STIFLE WITH CRCL RUPTURE? OA • Pain • Mobility impairment • Poor quality of life Chronic pain side effects • Central sensitization Predisposition to meniscal tear Increased loading of contralateral limb • Increased risk of contralateral CrCL rupture? TREATMENT OPTIONS Medical • Stability via periarticular fibrosis Surgical • None to moderate OA • Stifle stabilization techniques • Severe OA • Total knee replacement • Stifle arthrodesis • Amputation? See lecture on amputation and salvage procedures TREATMENT OPTIONS PARTIAL VERSUS COMPLETE CRCL TEARS Clinical signs = need for intervention Early stabilization irrespective of degree of tear • Preserves remnants • Reduces risk of meniscal damage • Reduces mechanical joint damage MEDICAL MANAGEMENT Activity restriction (6-8 weeks) Rehabilitation • +/- orthoses Weight management Pain management with NSAIDs • First 2 weeks • Try discontinuation after 2 weeks Recheck at 2, 4 and 8 weeks ACTIVITY AND REHABILITATION Restricted activity • 6-8 weeks; promoting joint fibrosis Rehabilitation goals • Muscle strengthening • Increasing joint mobility • Weight loss Balancing immobilization and maintenance of joint mobility ORTHOSES IN MEDICAL MANAGEMENT Orthosis: Single, rigid or semi-rigid device used to support a body part • Custom-made or ready to use orthoses? • Body shape, dog size, design • Cost and labor • Complications • Pressure sores • Refitting requirements • Inadequate periarticular fibrosis PAIN MANAGEMENT For acute inflammatory phase and OA No impact on stability Non-steroidal anti-inflammatory drugs (NSAIDs) • +/- others: Tramadol, codeine, gabapentin Acute phase • Opioid; rarely needed MEDICAL MANAGEMENT CANDIDATES Before and after surgery • Pending weight loss Need for delay in surgery • Obese patients; pending weight loss • Systemic or local infection • e.g., Urinary tract infection, pyoderma Poor candidates for stifle stabilization • High anesthetic risks • Severe OA • Financial constraints SURGICAL TREATMENT IN MATURE DOGS Extracapsular techniques • Passive and dynamic stability Osteotomy techniques • Dynamic stability only Intra-articular CrCL reconstruction • Biologic or synthetic grafts • Not recommended at this time MEASURES OF TREATMENT SUCCESS Clinical stifle stability tests • Cranial drawer: passive stability • Cranial tibial thrust: dynamic stability Radiographic evaluation • Metallic implants Long-term function • Mobility of joint • Resolution or decrease in lameness Level of need for long-term medical management EXTRACAPSULAR TECHNIQUES Lateral fabellotibial suture • Nylon leader lines • Secured with knots or metal crimps Anchor and bone tunnel-based sutures • Braided non-absorbable suture Treatment goal • Neutralize • Passive and dynamic cranial tibial translation • Excessive internal rotation • Short term stability relies on suture • Long term stability relies on periarticular fibrosis EXTRACAPSULAR TECHNIQUES POSTOPERATIVE CARE Pain management • 7-10 days Activity restriction • 6-8 weeks Rehabilitation • Conservative approach starting after 4 weeks Postoperative rechecks • 2 weeks • Incision check • 6-8 weeks • Check stability • Radiographs only if metallic implants present Both cranial drawer and tibial thrust must be negative OSTEOTOMY TECHNIQUES Tibia-based osteotomies Most common techniques • Tibial plateau leveling osteotomy (TPLO) • Tibial tuberosity advancement (TTA) • Cranial closing wedge osteotomy (CCWO) • CORA-based leveling osteotomy (CBLO) Treatment goal • Neutralize: dynamic cranial tibial translation • Dynamic stability relies on new orientation of joint TIBIAL OSTEOTOMIES Most common Tibial plateau leveling osteotomy (TPLO) • Rotation of the proximal segment reduces TPA • Better outcomes compared to TTA Tibial tuberosity advancement (TTA) • Tibial crest cranially advanced to make joint forces parallel to the patella tendon TPLO TPLO TTA TTA TIBIAL OSTEOTOMIES Additional techniques • Cranial closing wedge osteotomy (CCWO) • CORA-based leveling osteotomy (CBLO) • Combination of TPLO and CCWO • Very steep TPA cases CCWO CCWO CBLO TPLO+ CCWO OSTEOTOMY TECHNIQUES POSTOPERATIVE CARE Pain management • 7-10 days Activity restriction • 8-12 weeks Rehabilitation • Conservative approach starting after 2 weeks Postoperative rechecks • 2 weeks • incision check • Every 6-8 weeks • Check stability • Radiography for osteotomy healing and implant stability Only cranial tibial thrust must be negative TREATMENT OPTIONS IMMATURE PATIENT Early diagnosis is key Expedited surgical intervention Presurgical management • Activity restriction (crate) • Pain management • NSAIDs • Restrict activity Surgical options • Stabilization of avulsed fragment • Proximal epiphysiodesis to improve TPA • Repair of tear and stabilization of joint during healing TREATMENT OPTIONS IMMATURE PATIENT Stabilization of avulsed fragment • screw/pins Repair of ligament tear • Rarely possible due to size and timing Proximal tibial epiphysiodesis • Stunts growth plate cranially • Reduced TPA • Alleviates dynamic instability • Later stabilization may be needed • OA can still progress OSTEOTOMY TECHNIQUES IMMATURE DOGS Proximal osteotomies interfere with growth plates • Proximal tibial • Tibial tuberosity Premature, irregular closure of growth plates • Growth deformities • Clinical concern? Solution • Proximal partial tibial epiphysiodesis • Delay repair until growth plate closure • CBLO or CCWO CBLO CCWO OSTEOTOMIES VERSUS EXTRACAPSULAR Osteotomy techniques Extracapsular techniques • Advantages • Advantages • Better clinical outcome • More success in lean and small dogs • Faster return to function • $$ • Disadvantages • Technically simpler • $$$ • Dynamic and passive stability • Some complications can be catastrophic • Disadvantages • Dynamic stability only • Higher risk of failure • Heavier dogs • Larger breeds • Inferior clinical outcomes BILATERALLY AFFECTED CASES Single session bilateral versus staged bilateral procedures? • Patient • Ambulatory status • Body mass index • Size • Degree of compliance • Owner • Degree of compliance • Understanding of increased risks Preference: Staged > Single Session SMALL DOGS AND CATS Small and toy breed dogs • Functional outcome as important • Higher TPA than medium/large breed dogs Cats • CrCL rupture less common • Most cases are traumatic Surgical options • Osteotomy techniques • TPLO, TTA, CBLO • Extracapsular techniques SURGICAL VERSUS MEDICAL MANAGEMENT Comparison of outcome success rate and limb function Time Since Treatment Initiation Surgery + Post-Op Medical Management Medical Management Only Week 12 67.7% 92.6% 75% 47.1% 33.3% 63.6% Week 24 Week 52 CONCURRENT ANOMALIES IN STIFLE Meniscal tear Patella luxation • Medial (MPL) • Lateral (LPL) Osteochondral lesions Angular limb deformities • Femur • Tibia CONCURRENT STIFLE ANOMALIES Medial > lateral meniscal tears • Diagnosis via arthroscopy > arthrotomy • Debridement of damaged portion Meniscal release? • Falling out of favor • Damage to function of menisci • Missing tears not treated by release CONCURRENT STIFLE ANOMALIES Correction is possible • Single session procedures • Staged procedures Can be simple or complex Assessment by boarded surgeon is critical TAKE HOME MESSAGES • CrCL rupture is a common stifle pathology that is mostly degenerative in etiology • Early recognition of CrCL rupture is critical particularly in immature patients • CrCL deficient stifles benefit more from surgical stabilization • Medical management plays an important role as as an adjunctive treatment regiment in CrCL deficient stifles • Small breed dogs and cats are candidates for similar treatment approaches as large breed dogs • Concurrent anomalies of CrCL deficient stifles contributing to stifle instability need to be recognized and addressed if needed