Fracture management in cats represents a significant portion of feline orthopedic cases encountered in veterinary practice. The femur is the most commonly fractured bone in cats, representing 33-38% of all feline fractures.
Overview and Clinical Importance
Fracture management in cats represents a significant portion of feline orthopedic cases encountered in veterinary practice. The femur is the most commonly fractured bone in cats, representing 33-38% of all feline fractures. Feline fractures typically result from high-velocity trauma such as road traffic accidents, falls from height (high-rise syndrome), or dog bite wounds. Understanding proper fracture assessment, classification, and management principles is essential for achieving optimal patient outcomes.
Critical Concept: Cats are NOT small dogs when it comes to orthopedics. Important anatomical and physiological differences exist, including relatively thicker periosteum in young cats (approximately twice that of adult cats), smaller bone size limiting implant choices, and unique anatomical features such as the caudofemoralis muscle and supracondylar foramen.
| Classification |
Description and Clinical Significance |
| Open vs Closed |
Open: Bone communicates with external environment through skin wound. Closed: Skin intact. Open fractures carry higher infection risk and may require staged repair. |
| Complete vs Incomplete |
Complete: Bone completely separated. Incomplete: Greenstick (one cortex intact) or fissure fracture. Greenstick fractures in young cats may heal with cage rest alone. |
| Simple vs Comminuted |
Simple: Two fragments. Comminuted: Three or more fragments. Comminuted fractures require biological/bridging fixation approaches. |
| Fracture Line |
Transverse: Perpendicular to long axis. Oblique: Angled (greater than 30 degrees). Spiral: Rotational injury pattern. Short oblique fractures amenable to compression plating. |
| Anatomical Location |
Diaphyseal (shaft), Metaphyseal (flared region), Epiphyseal (articular end), Physeal (growth plate). Location determines surgical approach and implant selection. |
Fracture Classification
Basic Fracture Terminology
Understanding proper fracture terminology is essential for accurate documentation, communication, and treatment planning.
Salter-Harris Classification of Physeal Fractures
The Salter-Harris classification system is essential for describing fractures involving the growth plate (physis) in skeletally immature animals. In cats, physeal fractures are common, with the distal femur and distal tibia being frequently affected locations.
High-YieldRemember Salter-Harris types with the mnemonic "SALTR" - Separation (Type I), Above (Type II), Lower (Type III), Through (Type IV), Rammed/crushed (Type V). Types I and II are most common in cats, representing approximately 80% of feline physeal fractures.
| Type |
Description |
Clinical Notes |
| Type I |
Fracture through physis only (Separation) |
Common in capital femoral physis. Good prognosis. May be difficult to see radiographically if minimally displaced. |
| Type II |
Through physis + metaphyseal fragment (Above) |
Most common type overall. Distal femoral physeal fractures typically Type I or II. Good prognosis with proper fixation. |
| Type III |
Through physis + epiphyseal fragment (Lower) |
Articular involvement. Requires anatomical reduction. Higher risk of growth disturbance. |
| Type IV |
Through metaphysis, physis, and epiphysis (Through) |
Articular involvement. Must achieve anatomical reduction. Highest risk of growth disturbance and premature physeal closure. |
| Type V |
Crush injury to physis (Rammed) |
Rare. Often diagnosed retrospectively when premature physeal closure occurs. Poor prognosis for continued growth. |
Feline Fracture Epidemiology
Common Fracture Locations
NAVLE TipWhen you see a cat with suspected femoral fracture on NAVLE, remember: Femoral fractures ALWAYS require surgical stabilization (except greenstick in very young kittens). External coaptation (casts/splints) is NOT appropriate for femoral fractures due to inability to immobilize the hip joint.
| Bone |
Frequency |
Key Clinical Considerations |
| Femur |
33-38% of all fractures |
Most common. NOT amenable to casting. Risk of quadriceps contracture with delayed repair. Surgical stabilization required. |
| Tibia |
10-20% of all fractures |
Distal fractures often open. Higher complication rate (infection, delayed union, non-union). Limited soft tissue coverage distally. |
| Pelvis |
Common |
93% have multiple pelvic injuries. Monitor pelvic canal narrowing (greater than 45% = obstipation risk). Sacroiliac luxation most common. |
| Humerus |
5-13% of all fractures |
Supracondylar foramen unique to cats (contains median nerve and brachial artery). Avoid during pin/screw placement. |
| Radius/Ulna |
Less common |
Distal physeal damage can cause angular limb deformity due to paired bone growth disruption. |
Diagnostic Approach
Initial Assessment
Feline fractures typically result from high-velocity trauma, making concurrent injuries common. The initial focus must be on stabilization of major body systems (cardiovascular, respiratory, neurological) before addressing orthopedic injuries.
Assessment Priorities (in order)
- Cardiovascular assessment: Heart rate, pulse quality, mucous membrane color, CRT, blood pressure
- Respiratory assessment: Respiratory rate/effort, auscultation, pulse oximetry. Thoracic trauma present in 17% of cats with limb fractures
- Neurological assessment: Brief neuro exam BEFORE opioid administration (mentation, gait, withdrawal reflexes, deep pain)
- Pain management: Administer appropriate analgesia as a matter of urgency
- Orthopedic examination: Once patient stabilized - assess all limbs for swelling, crepitus, instability, pain
Diagnostic Imaging
Radiography remains the primary diagnostic modality for fracture assessment. Proper positioning under sedation or general anesthesia is essential for accurate interpretation.
Radiographic Requirements
- Orthogonal views (two perpendicular views) are essential for all suspected fractures
- Thoracic radiographs should be obtained in all trauma cases due to high incidence of concurrent thoracic injury
- Include joints above and below the suspected fracture site
- For proximal femoral fractures: obtain BOTH ventrodorsal extended-leg AND frog-leg views (fractures may be visible on only one view)
- Include measurement marker for accurate implant sizing
High-YieldFor proper lateral femur positioning, femoral condyles should be superimposed. On craniocaudal view: patella centered in trochlear sulcus, approximately 50% of lesser trochanter visible medially, and intercondylar notch walls appear as parallel lines.
| Fracture Type |
Reconstruction Approach |
Preferred Fixation |
| Articular fractures |
MUST be anatomically reconstructed |
Lag screws, K-wires, small plates |
| Simple transverse/oblique |
CAN and SHOULD be reconstructed |
Compression plating, lag screws with neutralization plate |
| Comminuted |
NOT amenable to reconstruction |
Bridging plate, plate-rod, ESF, interlocking nail |
Fracture Treatment Options
Treatment Decision Framework
Treatment selection depends on fracture type, location, patient age, and whether the fracture can be anatomically reconstructed.
Internal Fixation Methods
Bone Plates
Bone plates are the most versatile and commonly used fixation method for feline long bone fractures. The 2.4 mm plating system is highly appropriate for most cat femoral fractures, with 2.7 mm plates considered for larger cats.
Plate Application Modes
- Compression: Fracture fragments compressed together. Load shared between bone and plate. For simple, reconstructable fractures.
- Neutralization: Lag screw achieves compression; plate protects from bending/torsion. For oblique/spiral fractures.
- Bridging: No interfragmentary compression. Plate takes all load. For comminuted, non-reconstructable fractures.
Intramedullary (IM) Pins
Critical Point: IM pins as SOLE fixation are NOT recommended for feline femoral fractures. They resist bending but NOT rotational forces. Complications include pin migration, fissure formation, and non-union.
Appropriate uses of IM pins: Combined with plate (plate-rod construct) to reduce plate strain and increase construct strength, or combined with external skeletal fixator (tied-in ESF).
External Skeletal Fixation (ESF)
ESF provides fracture stabilization using percutaneous transfixation pins connected to an external frame. Particularly useful for open fractures, comminuted fractures, and fractures below the elbow/stifle.
NAVLE TipESF complications occur in approximately 19% of feline cases, with the femur (50%), tarsus (35%), and radius/ulna (33%) having highest complication rates. Superficial pin tract infection and implant failure are most common complications.
| Plate Type |
Characteristics |
Best Applications |
| DCP |
Dynamic Compression Plate. Oval holes allow eccentric screw placement for compression. |
Simple transverse fractures where interfragmentary compression desired |
| LCP |
Locking Compression Plate. Threaded holes accept locking screws. Functions as internal fixator. |
Comminuted fractures, osteoporotic bone, biological bridging |
| VCP |
Veterinary Cuttable Plate. Stackable, cuttable, accepts multiple screw sizes (1.5-2.7mm). |
Versatile, cost-effective option. Cannot compress transverse fractures. |
Regional Fracture Management
Femoral Fractures
The femur is divided into three regions for fracture classification: proximal (head, neck, greater trochanter, subtrochanteric), diaphyseal (shaft), and distal (supracondylar, physeal, condylar).
Tibial Fractures
Tibial fractures account for 10-20% of all feline fractures. The majority are mid- to distal diaphyseal fractures. Key considerations include: higher complication rates (infection, delayed union, non-union), limited soft tissue coverage distally, and high incidence of open fractures at distal locations.
Treatment Options
- Plate fixation: ORIF with plate alone or plate-rod. Orthogonal plating via MIPO approach.
- External skeletal fixation: Type I, Type II, or circular-linear hybrid ESF. Excellent for open/contaminated fractures.
- IM pins: Must be combined with plate or ESF. Insert normograde (retrograde causes patellar tendon impingement in cats).
High-YieldThe feline fibula is very thin and does NOT contribute to weight bearing. However, it IS important for stifle and tarsal joint stability as it serves as attachment for lateral collateral ligaments. Usually both tibia and fibula are fractured together.
Pelvic Fractures
Pelvic fractures are common in cats following trauma. 93% of cats have multiple pelvic injuries, with sacroiliac fracture-luxation being most common. Treatment decisions based on: pelvic canal narrowing, weight-bearing axis involvement, and neurological status.
| Type |
Configuration |
Applications |
| Type I |
Unilateral, uniplanar. Half-pins exit one skin surface only. |
Femur, humerus (where body wall limits bilateral access). Often with tied-in IM pin. |
| Type II |
Bilateral. Full pins exit both skin surfaces. |
Radius/ulna, tibia. More rigid than Type I. |
| Tied-in ESF |
Type I ESF combined with IM pin incorporated into connecting bar. |
Excellent for comminuted femoral fractures. Increases construct rigidity. |
Complications of Fracture Repair
Quadriceps Contracture
Quadriceps contracture is a devastating complication characterized by progressive stifle hyperextension and muscle fibrosis. It most commonly occurs following distal femoral fractures, particularly in young animals.
Risk Factors
- Young age (immature animals at highest risk)
- Delayed fracture repair
- Mid-diaphyseal and distal femoral fractures
- Extensive muscle contusion or laceration
- Limb immobilization in extension
Prevention and Treatment
Prevention: Early fracture repair (do not delay unnecessarily), early passive range of motion exercises, appropriate analgesia to encourage limb use.
Treatment: Surgical release of adhesions between quadriceps and femur, dynamic flexion apparatus to maintain stifle flexion, intensive physiotherapy. Early intervention critical - irreversible muscle fibrosis occurs over time.
High-YieldQuadriceps contracture is characterized by stifle hyperextension, inability to flex the stifle, and genu recurvatum posture. If you see a young cat with recent femoral fracture history presenting with stiff hindlimb held in extension, think quadriceps contracture immediately!
Other Complications
| Fracture Location |
Treatment Options |
Special Considerations |
| Capital physeal/Femoral neck |
2 parallel K-wires (preferred). Lag screw with anti-rotational K-wire (large adults). FHO if non-repairable. |
Minimize vascular damage. May occur in cats older than 12 months due to delayed physeal closure from early neutering. |
| Greater trochanter avulsion |
Pin and tension band wire (most common). Lag screw. Small bone plate. |
Often concurrent with hip luxation. Frequently missed - careful radiographic assessment required. |
| Diaphyseal - Simple |
Compression plate (DCP/LCP). Interlocking nail. Lag screw with neutralization plate. |
2.4 mm plates appropriate for most cats. Aim for 3 bicortical screws per fragment minimum. |
| Diaphyseal - Comminuted |
Bridging plate. Plate-rod construct. Tied-in ESF. Interlocking nail. |
Biological approach - preserve blood supply. Do NOT attempt anatomical reconstruction. |
| Distal physeal |
Crossed K-wires (most common). Rush pins. Small plates. |
Usually Salter-Harris Type I or II. Higher risk of quadriceps contracture. Prompt repair essential. |
Bone Healing and Postoperative Care
Expected Healing Times
Recommended Radiographic Follow-up
- Patients up to 3 months of age: 4 weeks postoperatively
- Patients 3-12 months of age: 6 weeks postoperatively
- Patients greater than 12 months of age: 8 weeks postoperatively
- Highly comminuted fractures: Up to 10 weeks postoperatively
Postoperative Care Principles
- Activity restriction: Cage rest or small room confinement until radiographic evidence of healing
- Analgesia: Multimodal approach - NSAIDs (meloxicam), gabapentin (5-10 mg/kg PO q8-12h), buprenorphine
- Physical rehabilitation: Passive range of motion, massage to reduce swelling, encourage early weight bearing
- Bandage care (if applicable): Regular changes, monitor for pressure sores, constriction
- ESF pin tract care: Daily cleaning, monitor for excessive discharge or loosening
| Surgical Indications |
Conservative Management |
Prognosis |
| Pelvic canal narrowing greater than 45%
Weight-bearing axis disruption (ilium, acetabulum, sacroiliac)
Inability to ambulate
Nerve impingement
Bilateral injuries |
Minimal displacement
Non-weight-bearing axis fractures
Pelvic canal continuity maintained
Successful in approximately 75% of cases |
Generally good with appropriate treatment
Cage rest 2-8 weeks required
Pelvic canal narrowing greater than 45% increases obstipation/megacolon risk |
| Complication |
Risk Factors |
Management |
| Osteomyelitis |
Open fractures, contamination, poor surgical technique, implant loosening |
Culture/sensitivity, appropriate antibiotics, debridement, implant removal if loose |
| Delayed union |
Inadequate fixation, excessive motion, poor blood supply, comminution |
Extended healing time expected. Continued activity restriction. Re-evaluate fixation. |
| Non-union |
Severe motion/instability, infection, poor blood supply |
Revision surgery with more rigid fixation, bone grafting |
| Malunion |
Poor reduction, implant failure, inappropriate fixation |
Corrective osteotomy if functionally significant |
| Premature physeal closure |
Physeal damage from trauma or surgery, implants crossing physis |
Angular limb deformity possible. May require corrective surgery. |
| Patient Category |
Expected Healing Time |
| Immature cats (less than 3 months) |
3-5 weeks (clinical union) |
| Young cats (3-12 months) |
4-6 weeks (clinical union) |
| Adult cats (greater than 12 months) |
6-10 weeks (clinical union) |
| Comminuted fractures |
Up to 10-12 weeks |