High-quality radiographs are the foundation of TPLO planning and post-operative assessment. The tibial plateau angle (TPA) measurement that determines plate size, osteotomy arc, and rotation amount depends entirely on image quality.

A poorly positioned radiograph produces inaccurate TPA measurements, which can lead to undercorrection, overcorrection, or incorrect implant selection.

Understanding what makes a TPLO radiograph diagnostically reliable is essential for any veterinary professional involved in TPLO cases.

Quick answer: A diagnostic TPLO lateral radiograph requires: stifle and hock at approximately 90 degrees; tibia and fibula superimposed throughout; femoral condyles superimposed; the entire tibia visible; and the beam centered over the stifle. Femoral condyle non-superimposition is the most common cause of TPA measurement error.

Key takeaways

• Limb positioning is the single most important variable for TPA accuracy: limb positioning affects the appearance of anatomic landmarks used for TPA determination
• The femoral condyles must be superimposed on the lateral view: MDPI research confirms 3 mm non-superimposition produces 90.6% of measurements within 1 degree of true TPA; error increases substantially beyond 3 mm
• The stifle and hock should both be at approximately 90 degrees for the lateral view: this is required for accurate tibial plateau angle measurement
• Sedation is recommended: a sedated dog allows accurate limb placement without motion artifact; an unsedated dog in pain cannot maintain the required positioning
• The TPA averages 23 to 29 degrees in most dogs: some small breeds average higher; dogs with TPA over 30 degrees may be poor candidates for extracapsular repair or TTA
• Post-operative TPA target is 5 to 6.5 degrees: achieving this angle eliminates cranial tibial thrust; post-operative radiographs confirm whether the target was achieved

Why radiograph quality matters for TPLO

TPLO planning is based entirely on the pre-operative lateral stifle radiograph. From this image, the surgeon:

• Measures the TPA (tibial plateau angle)
• Selects the appropriate osteotomy saw blade radius
• Plans the rotation amount needed to achieve the target post-operative TPA (5 to 6.5 degrees)
• Selects the implant size (plate and screw dimensions)

A 2-degree error in TPA measurement from a poorly positioned radiograph can result in a plate one size too small or large, or an osteotomy rotation that undercorrects or overcorrects the joint.

Today's Veterinary Practice confirms: a well-positioned lateral stifle radiograph is essential for accurate diagnostic interpretation and TPA measurement; correct tibial alignment is most important for TPA measurement.

The lateral (mediolateral) projection

This is the critical image for TPA measurement.

Patient positioning

Body position: the dog is placed in lateral recumbency with the limb of interest (affected stifle) closest to the table. The limb is extended slightly away from the body.

Stifle angle: the stifle is positioned at approximately 90 degrees of flexion.

Hock angle: the hock (tarsus) is positioned at approximately 90 degrees of flexion.

Cave Vet Specialists confirms: ensure the stifle and hock are collimated into the area of interest; keep the leg in a natural position; place an appropriate-sized plate under the limb.

Femoral condyles: both femoral hemicondyles should be precisely superimposed. This is the most technically demanding aspect of lateral stifle radiography. To achieve superimposition, the opposite limb is elevated with foam wedges or a triangular positioning aid to allow the limb of interest to lie flat and parallel to the table.

Cave Vet Specialists confirms: place the non-interest limb onto wedges to tilt the limb of interest centrally; place a triangular wedge or sandbag on the opposite side.

Tibia-fibula superimposition: the tibia and fibula should be superimposed throughout their full length. If the tibia and fibula are not superimposed, the tibia is rotated relative to the plate -- and this same rotation is captured in the TPA measurement.

What to include

The radiograph must include the entire tibia from the tibial plateau (top) to at least the distal metaphysis (ideally the entire bone).

Today's Veterinary Practice confirms: the x-ray beam should be centered over the stifle joint with collimation to include the entire tibia.

The most common positioning errors

Femoral condyle non-superimposition: the most frequent and most impactful error. Caused by the hindquarters tilting, the contralateral limb not elevated sufficiently, or the dog being unsedated and shifting position.

The MDPI Animals research quantified the impact: 3 mm of non-superimposition produces about 1 degree of TPA error; errors increase substantially beyond 3 mm.

Tibial rotation: the tibia is internally or externally rotated relative to the true mediolateral plane. This occurs when the hock is not held in a natural position. Rotation changes the apparent slope of the tibial plateau and produces a falsely high or low TPA.

Today's Veterinary Practice confirms: the tibia can easily be rotated with CCL injury even when the femur appears straight.

Incomplete tibia: if the distal tibia is cut off by collimation, the surgeon cannot assess the full tibial axis -- which is required for TPA measurement.

The caudocranial (CrCd or AP) projection

The caudocranial view assesses limb alignment, varus and valgus deformity, and tibial torsion. It is a standard part of the pre-operative TPLO radiograph set.

Patient positioning

The dog is placed in sternal recumbency or dorsal recumbency with the affected limb extended caudally (toward the x-ray plate). The stifle and hock should be visible.

Rita Leibinger confirms: the AP projection must have the stifle and tarsus included for the attending surgeon to assess limb alignment.

DVM360 confirms: on the caudocranial view, the medial margin of the tuber calcis should align with the center of the distal tibia, confirming the absence of tibial torsion.

Calibration for surgical planning

When radiographs will be used for surgical planning (plate size selection), a calibration marker must be placed at the same level as the stifle joint.

This allows the surgeon to scale the digital image to real-world measurements.

Rita Leibinger confirms: image calibration does not alter TPA measurement (the angle is size-independent), but it enables radiographs to be used for surgical plate-size planning.

Post-operative radiographs

After TPLO, radiographs are taken:

• Immediately post-surgery: to confirm osteotomy position, plate position, screw placement, and achieved post-operative TPA
• At 6 to 8 weeks: to assess early bone healing and callus formation
• At 12 weeks: to confirm bone union before lifting activity restrictions

What a good post-operative radiograph shows

• Post-operative TPA of approximately 5 to 6.5 degrees
• No screws violating the joint space
• Plate in correct medial position on the tibia
• Osteotomy gap that is progressively narrowing on follow-up films (callus formation)

Warning signs on post-operative radiographs

• Screw tip in the joint space (requires removal of that screw)
• Plate migration from original position
• Peri-implant radiolucent halos (suggests implant loosening or infection)
• Osteotomy gap not narrowing by 8 weeks (suggests delayed union or infection)

For the TPA measurement guide, see what causes TPLO surgery in dogs. For post-operative complications, see 15 common complications after TPLO surgery.

For the plate infection guide, see TPLO plate infection signs and treatment. For bone healing information, see TPLO bone healing time in dogs.

Frequently asked questions

Does the dog need to be sedated for TPLO radiographs?

Sedation is strongly recommended and preferred. An unsedated dog -- particularly one in pain from CCL disease -- cannot maintain the precise positioning required for accurate TPA measurement.

Even minor position changes between preparation and exposure produce significant error. Sedation allows the technician to position the limb correctly and hold it in place without the dog shifting.

Why does the hock position matter for the lateral view?

The hock angle affects the position of the tibia relative to the table and the imaging plate.

When the hock deviates from approximately 90 degrees, the tibia is either elevated or depressed at the distal end, which changes the apparent angle of the tibial plateau.

This error is captured in the TPA measurement.

What is a normal TPA range and when should TPLO be recommended?

Today's Veterinary Practice confirms the average TPA in most dogs is 23 to 29 degrees. Some small breeds have higher averages.

Dogs with TPA greater than 30 degrees may be poor candidates for extracapsular repair or TTA.

TPLO is appropriate for dogs of all TPA values -- the procedure specifically corrects whatever TPA angle the dog presents with.

Can the same radiograph be used for both diagnosis and surgical planning?

Yes, if it is of adequate quality and includes a calibration marker.

Diagnostic-only radiographs taken without a calibration marker can confirm CCL disease and measure TPA, but cannot be used for plate-size surgical planning.

Including a calibration marker at the time of acquisition allows a single radiograph to serve both purposes.

What happens if the TPA is measured incorrectly pre-operatively?

If the pre-operative TPA is underestimated, the surgeon may under-rotate the osteotomy and fail to reach the target 5 to 6.5 degree post-operative TPA.

This results in residual cranial tibial thrust and potentially ongoing instability. If overestimated, overcorrection is possible.

This underscores why positioning accuracy at the time of radiography is critical -- errors propagate through the entire surgical plan.

Resources

• Cave Vet Specialists. Tips for TPLO Radiographs. cave-vet-specialists.co.uk
• Today's Veterinary Practice. Cruciate Disease: How and Why to Measure Tibial Plateau Angle. todaysveterinarypractice.com
• MDPI Animals. The Effect of Femur Positioning on Measurement of Tibial Plateau Angle. ncbi.nlm.nih.gov
• Rita Leibinger. TPLO Surgical Technique. leibinger.vet

Returning an agility dog to sport after TPLO surgery requires more than standard recovery. The standard 8 to 12 week bone healing protocol restores a dog to normal household function.

Returning to agility -- a high-impact sport involving jumping, sharp turns, weave poles, and contact obstacles -- requires a further 4 to 6 months of structured conditioning on top of that foundation.

Quick answer: Most agility dogs return to training 7 to 9 months post-TPLO. The Balanced Dog confirms 80% returned before 9 months (average 7.5 months). Bone healing at 8 to 12 weeks is the starting point. Return to sport requires muscle symmetry, pain-free movement, and a graduated protocol with vet clearance.

Key takeaways

• The return-to-agility timeline averages 7 to 9 months: The Balanced Dog confirms 80% returned before 9 months, average 7.5 months; 3 to 6 months reflects light training, not full competition
• Bone healing at 8 to 12 weeks is the starting point, not the endpoint: high-impact agility may require 4 to 6 more months; healed bone does not mean rebuilt muscle
• Agility-specific demands require agility-specific conditioning: jumping, tight turns, weave poles, and contacts generate forces far greater than walking; the dog must be conditioned for these before returning
• All dogs with agility return goals need a return-to-sport protocol: it adds sport-specific movement, progressive jumping, and fitness benchmarks beyond the standard recovery protocol
• Veterinary clearance at each phase is non-negotiable: vet or surgeon clearance is required before resuming training; no benchmark should be self-assessed
• Not all dogs will reach pre-surgery performance: most regain significant function but some need training changes to reduce joint stress

Why agility is a higher bar than normal recovery

Normal TPLO recovery targets return to household mobility: walking, light running, stairs, and play. Agility sport involves:

• Jumping: impact forces on landing of 2 to 3 times body weight
• Tight turns at speed: high lateral shear forces on the stifle
• Weave poles: rapid lateral flexion and extension
• Contact obstacles (A-frame, dog walk, teeter): climbing and controlled descent under dynamic loading

Each of these demands requires not just healed bone but fully rebuilt muscle, coordinated neuromuscular control, and joint proprioception. These take months to restore after TPLO.

SustainableVet.org confirms: dogs in sports or agility should reintroduce jumps and running only after veterinary clearance; swimming or uphill walking maintains muscle tone during the conditioning phase.

The return-to-sport timeline

Phase 1: bone healing (weeks 0 to 12)

Standard TPLO recovery. Strict confinement, graduated leash walking, and passive range-of-motion exercises. No running, jumping, or agility activity of any kind.

Radiographic bone healing is confirmed at the 8 to 12 week recheck. This is the gate that opens Phase 2.

Phase 2: rebuilding foundation fitness (months 3 to 5)

After bone healing is confirmed, the focus shifts to rebuilding the muscle mass and neuromuscular coordination that atrophied during the restriction period.

Activities during Phase 2:

• Progressive leash walking with duration increasing weekly
• Hydrotherapy (underwater treadmill) for muscle building without joint impact
• Hill walking (controlled inclines) to load the hip extensors and stifle stabilizers
• Balance and proprioception work (wobble boards, cavaletti poles)
• Core strengthening exercises

TPLO Info confirms: overall return to agility takes around 3 to 6 months; this period of rebuilding is what fills the gap between bone healing and sport re-entry.

Phase 3: sport-specific conditioning (months 5 to 7)

Once the dog has rebuilt baseline fitness, sport-specific conditioning begins. This is distinct from the standard recovery protocol.

Activities:

• Controlled jumping starting very low (4 inches for a dog that jumps 24 inches in competition) and increasing progressively over 6 to 8 weeks
• Slow figure-8 work and curved running to restore stifle lateral mechanics
• Individual weave pole work at slow speed before full weave sequence
• Contact obstacle approach and exit work at slow, controlled speed
• Video gait assessment to identify any asymmetry or compensation patterns

Petcarepartners.co confirms: most vets suggest a waiting period of 4 to 6 months for running and fetch; for agility, add a further structured sport-specific phase on top of this.

Phase 4: return to full competition (months 7 to 9+)

Full competition resumption follows veterinary clearance of the sport-specific conditioning phase. The criteria for clearance include:

• Pain-free movement through full range of stifle motion
• Muscle symmetry (thigh circumference equal bilaterally)
• Confident single-leg weight bearing during agility-specific movements
• No lameness following a full practice session
• Surgeon clearance based on physical and radiographic assessment

The Balanced Dog confirms: it typically takes 7 to 9 months to return to sport; 80% of dogs returned to agility before 9 months with a good rehabilitation and return-to-sport program.

Factors that affect the return timeline

Dog's age: younger dogs (under 4 years) typically rebuild muscle faster than older dogs. Senior dogs may take 10 to 12 months or longer.

Dog's pre-surgical fitness: well-conditioned sport dogs with strong baseline muscle mass rebuild faster than deconditioned dogs. Body condition score at the time of surgery matters.

Adherence to the restriction protocol: dogs that were overactive during weeks 1 to 6 may have developed micro-complications or delayed healing that shifts the timeline.

Concurrent meniscal tear: dogs that had a meniscal tear treated at the time of TPLO may need additional time, particularly if a late meniscal tear occurs during the return-to-sport phase.

Bilateral CCL disease: dogs with CCL rupture on the second side during or after recovery for the first require the full protocol on the second side before bilateral agility work resumes.

SustainableVet.org confirms: average recovery time to agility is about seven months; some dogs start controlled activity at six months, while others take up to two years.

Using a certified canine rehabilitation therapist

For agility dogs, professional rehabilitation is strongly recommended rather than a home-only protocol. Certified canine rehabilitation practitioners (CCRPs) provide:

• Biomechanical gait analysis to detect compensatory movement patterns before return to sport
• Underwater treadmill protocols calibrated to the specific demands of agility
• Sport-specific functional testing to determine readiness
• Individualized return-to-sport programs

The Balanced Dog confirms: surgery is just the start; a good-quality rehabilitation and return-to-sport program is instrumental in giving the dog the best chance at returning to competitive agility.

For the recovery timeline, see what to expect after TPLO surgery in dogs. For physical therapy timing, see when to start physical therapy after TPLO surgery.

For recovery exercises, see TPLO recovery exercises for dogs. For the failure rate overview, see TPLO failure rate in dogs.

Frequently asked questions

My agility dog had TPLO 6 months ago and is moving well. Can she start jumping?

Six months is within the average return-to-sport window but requires veterinary assessment before starting jumping.

The criteria -- muscle symmetry, pain-free full range of motion, confident single-leg weight bearing -- must be met and confirmed by your vet or rehabilitation therapist before any jumping begins.

Do not self-assess readiness.

Will my dog ever compete at the same level as before TPLO?

Many dogs do return to pre-injury competitive levels, especially those with strong pre-surgical conditioning and an excellent rehabilitation program.

SustainableVet.org confirms most dogs regain significant function and can participate in agility, though not all will reach pre-injury performance levels. The Balanced Dog study confirms 80% returned before 9 months.

Should I lower my dog's jump height after TPLO?

Discuss with your vet. Some dogs perform best at a jump height one level below their pre-surgery height to reduce cumulative joint loading. Others return to their full height without adjustment.

This is an individual decision based on the dog's age, size, arthritis level, and post-recovery movement quality.

Can I use a FitPaws or conditioning equipment at home?

Yes -- proprioception and balance equipment (wobble boards, FitPaws equipment, balance pads) is appropriate during Phase 2 and Phase 3 under the direction of your rehabilitation therapist.

These tools help rebuild the neuromuscular coordination needed for agility-specific movements. Always use on non-slip flooring.

What happens if my dog tears the other CCL during agility return?

Bilateral CCL disease is common (30 to 40% of dogs develop it). If the second stifle becomes symptomatic during the return-to-agility phase, the rehabilitation program pauses and the second stifle is assessed.

The return-to-agility timeline resets based on the second surgery date. Most dogs with bilateral TPLO can still return to agility.

Resources

• The Balanced Dog. Returning to Dog Agility After TPLO Surgery. the-balanced-dog.com
• TPLO Info. Can You Resume Dog Agility Training After TPLO Surgery? tploinfo.com
• SustainableVet. When Can Dogs Resume Agility Training Post-TPLO? sustainablevet.org
• ACVS. Cranial Cruciate Ligament Disease. acvs.org

A seroma is one of the most common soft tissue complications after TPLO surgery in dogs.

Finding a soft lump under the skin near the surgical site is alarming, but in most cases it is a benign finding that resolves with strict rest and time.

Understanding the difference between a seroma and a more serious complication helps you respond appropriately.

Quick answer: A seroma is clear serum fluid under the TPLO incision, not an infection. Small seromas resolve in 1 to 3 weeks with rest; larger ones need sterile aspiration. Call your vet if the swelling is hot, fast-growing, or producing discharge.

Key takeaways

• A seroma is clear serum fluid under the skin — not an infection; a benign accumulation from disrupted blood and lymphatic vessels
• Excessive activity is the leading preventable cause: unnecessary movement produces more fluid and enlarges the seroma
• Small seromas resolve with strict rest in 1 to 3 weeks: the lymphatic system reabsorbs the fluid without intervention
• Large seromas may need needle aspiration: a sterile outpatient procedure by your vet; never drain at home
• Warm packs twice daily help reabsorption: 10 minutes of warmth twice daily is recommended for established seromas
• A seroma that becomes warm, red, painful, or produces discharge needs immediate vet attention it may have become infected

What is a seroma?

Vetinfo explains that a seroma is a swelling resulting from the accumulation of fluid under the skin.

It is made of serous fluid (blood plasma without most of the cells), so it is usually watery with a slight pink tinge rather than dark blood or cloudy infected fluid.

After TPLO surgery, the osteotomy site and surrounding soft tissues leave behind a space between tissue layers called dead space where fluid from disrupted capillaries and lymphatics can collect.

The fluid pools there before the body's healing processes close the space.

Seromas feel soft, fluctuant (squishy), and move under finger pressure. They are usually not painful when small and are not warm to the touch.

These features distinguish them from infections, which are typically warm, firm, painful, and may produce purulent discharge.

What causes seromas after TPLO?

Excessive activity

This is the most important and most preventable cause. Vetinfo confirms that seromas occur when a dog is active immediately after surgery instead of remaining inactive during recovery.

Every unnecessary step disrupts the tissue planes that need to approximate and seal, producing more fluid.

The surgeon Dr.

Matt confirms on JustAnswer that the best way to reduce seromas is to restrict activity as much as possible at least 8 weeks of restricted activity after TPLO is recommended.

Dead space at the surgical site

TPLO surgery involves significant soft tissue dissection around the proximal tibia. Closing this space with sutures reduces but does not eliminate dead space.

Any gap between tissue layers fills with fluid before normal healing closes it.

Surgical drainage

In some cases, surgical drains are placed during the procedure to allow fluid to escape rather than collect.

Not all surgeons routinely place drains some reserve them for dogs considered at higher risk of seroma formation.

Patient factors

Larger dogs produce more dead space and more fluid. Dogs with more subcutaneous fat are at higher risk.

Dogs that are particularly active during recovery despite attempts at confinement are most likely to develop significant seromas.

Recognizing a seroma

Classic signs:

• Soft, squishy swelling directly under or near the incision site
• The swelling moves under pressure it feels like a water balloon
• Normal skin color over the swelling (not red or purple)
• Not painful when gentle pressure is applied
• Not warm to the touch
• No discharge from the skin over the swelling

When to suspect infection instead:

• The swelling is warm, red, or firm rather than soft
• A draining tract or discharge appears from the skin
• The dog shows increased pain, fever, lethargy, or loss of appetite
• The swelling is growing rapidly

Treatment

Small seromas: observation and rest

Cuteness notes that most often the body absorbs the fluid and the swelling diminishes. For small seromas (typically under 3 cm), the approach is:

• Enforce strict activity restriction no running, jumping, or free roaming
• Cold compresses in the first few days (reduces new fluid production)
• Warm compresses from days 5 onward 10 minutes, twice daily to promote fluid reabsorption
• Monitor size and character daily

Large or persistent seromas: needle aspiration

Large seromas that are uncomfortable or not responding to rest may be drained by your veterinarian using a sterile needle and syringe. This is a simple outpatient procedure.

Cuteness confirms that veterinarians may drain or aspirate the seroma to make the dog more comfortable.

Aspiration provides relief but does not address the underlying dead space. The seroma may refill sometimes multiple aspirations are required. After aspiration, continued strict rest is essential.

Compression bandaging

A gentle compression bandage applied by your vet reduces dead space and discourages fluid refilling after aspiration.

Improper bandaging can cause pressure sores or circulatory compromise, so bandages must be applied and monitored by a veterinarian.

Surgical drain placement

If a seroma repeatedly refills after aspiration, a closed suction drain may be placed to allow ongoing drainage until the dead space closes.

This is uncommon but is an option for persistent or large seromas.

For the full fluid buildup guide covering all types of post-TPLO fluid accumulation, see fluid buildup after TPLO surgery in dogs.

For incision complications including infection, see TPLO incision infection symptoms and prevention. For the full complications reference, see 15 common complications after TPLO surgery in dogs.

For the incision redness guide to distinguish seroma from infection, see redness after TPLO surgery in dogs: causes and care.

Frequently asked questions

Can a seroma go away on its own?

Yes in the majority of cases, small seromas resolve without intervention as the body reabsorbs the fluid over 1 to 3 weeks.

Strict activity restriction is essential; without it, the seroma will continue to refill as fast as it drains.

Do not assume a seroma will resolve if the dog is not being properly confined.

Should I drain the seroma myself at home?

Never. Home drainage risks introducing bacteria into a sterile fluid collection, converting a benign seroma into an infected abscess. Only a veterinarian should aspirate a seroma under sterile conditions.

If you believe the seroma needs draining, contact your vet.

My dog's seroma looks like it ruptured through the skin. What do I do?

Spontaneous seroma rupture does occasionally occur. The fluid drains through the skin, leaving a small wound.

Contact your vet immediately for guidance the wound will need to be kept clean and monitored for infection. A veterinarian Dr.

Matt reports this occurrence on JustAnswer, confirming prompt vet contact is appropriate.

How long does a seroma last after TPLO?

Small seromas typically resolve in 1 to 3 weeks with strict activity restriction. Larger ones may take 4 to 6 weeks and may require aspiration.

If a seroma persists beyond 4 weeks without improvement, a veterinary recheck is warranted.

Is a seroma the same as an infection?

No. A seroma is sterile fluid no bacteria. An infection involves bacterial colonization and produces different characteristics: warmth, redness, purulent discharge, systemic illness signs.

Bacterial culture distinguishes them definitively if clinical assessment is uncertain.

Resources

• Vetinfo. Seroma After-Surgery Care for Dogs. vetinfo.com
• Cuteness. What Are the Treatments for Seroma Formation in Dogs? cuteness.com
• VCA Animal Hospitals. Seroma in Dogs. vcahospitals.com
• TPLO Info. Recovery FAQs. tploinfo.com

TPLO (tibial plateau leveling osteotomy) is the most widely performed surgery for cranial cruciate ligament (CCL) rupture in dogs.

It is the procedure most commonly recommended by board-certified veterinary surgeons for medium and large dogs, and it has the most extensive published evidence base of any CCL repair technique.

Understanding what TPLO is, why it works, and what recovery involves helps owners make informed decisions and prepare for the process.

Quick answer: TPLO (tibial plateau leveling osteotomy) corrects CCL rupture by changing tibial plateau geometry to eliminate the shear force making the CCL unnecessary. A curved cut is made through the tibia, rotated to 5 degrees, and secured with a locking plate while the bone heals. Success rate is 90 to 95%.

Key takeaways

• TPLO stands for tibial plateau leveling osteotomy: it levels the tibial plateau through a bone cut to stabilize the stifle without relying on the damaged CCL
• TPLO corrects CCL rupture by eliminating the shear force the CCL resists: it changes the tibial plateau geometry so the joint is stable without a CCL
• The procedure achieves a post-operative tibial plateau angle of approximately 5 degrees: VCA confirms the tibial plateau is rotated until appropriately level (ideally 5 degrees), eliminating cranial tibial thrust
• TPLO has a 90 to 95% success rate: RCVS confirms 90 to 95% of dogs regain complete or near-complete function; 93% of owners report satisfaction at 12 months
• Recovery requires 8 to 12 weeks of activity restriction for bone healing; progressive return to full activity follows; muscle recovery takes up to 6 months
• TPLO is the most commonly recommended procedure for CCL rupture by ACVS surgeons in dogs over approximately 15 to 20 kg

The CCL and why it ruptures

The cranial cruciate ligament (CCL) is the equivalent of the human ACL in dogs.

It connects the femur (thigh bone) to the tibia (shin bone) inside the stifle (knee) joint and serves three primary functions:

• Preventing the tibia from sliding forward relative to the femur during weight bearing
• Limiting internal rotation of the tibia
• Preventing hyperextension of the stifle

Unlike most human ACL tears (which are acute traumatic events), CCL rupture in dogs is typically degenerative. The fibers weaken progressively over months to years before the ligament fails completely.

By the time complete rupture occurs, most of the fibers have already been compromised.

This is why the contralateral (opposite) CCL is also at risk -- the same degenerative process typically affects both stifles.

When the CCL ruptures, the tibial plateau's natural slope creates an unconstrained cranial shear force during weight bearing.

The femur slides down the tibial plateau, the tibia shifts forward, and the dog is in pain and unable to use the leg normally.

CCL rupture is one of the most common orthopedic injuries in dogs. High-risk breeds include Labrador Retrievers, Rottweilers, Staffordshire Terriers, Mastiffs, Newfoundlands, and German Shepherds.

Neutered dogs have a higher risk than intact dogs of the same breed.

How TPLO works: the biomechanical principle

The normal canine tibial plateau slopes downward from front to back at approximately 23 to 29 degrees (the tibial plateau angle, or TPA).

When the dog bears weight, this slope creates a cranial shear force -- the tibia tries to slide forward relative to the femur. In a normal stifle, the CCL resists this force.

When the CCL is absent, the force is unopposed and the joint is unstable.

TPLO does not attempt to restore the CCL. Instead, it eliminates the shear force entirely.

By rotating the tibial plateau to approximately 5 degrees, the joint surface becomes level enough that the patellar tendon -- rather than the CCL -- provides the stabilizing force during weight bearing.

The joint is mechanically stable without any ligament. The need for the CCL is eliminated by changing the geometry of the tibial plateau.

Dispomed confirms: TPLO addresses CCL rupture by altering the biomechanics of the stifle. The tibial plateau normally slopes downward; TPLO creates a flat or level plateau, decreasing sliding motion at this joint.

The TPLO procedure: step by step

Pre-operative planning

Before surgery, the dog is sedated and lateral stifle radiographs are taken.

The surgeon measures the TPA from these images and calculates the amount of rotation required to achieve the target post-operative TPA of approximately 5 degrees.

The surgeon also selects the appropriate saw blade radius and implant size based on these measurements and the dog's body weight.

Anesthesia and preparation

The dog is placed under general anesthesia. The surgical site is clipped and prepared with antiseptic solution. IV antibiotics (typically cefazolin) are given before the incision.

Joint inspection and meniscal assessment

The surgeon makes an incision over the medial aspect of the proximal tibia and performs a small arthrotomy (opening into the joint) to inspect the menisci.

Damaged meniscal tissue is removed at this stage.

Chewy confirms: during surgery, the joint is examined and the surgeon might remove damaged tissue before proceeding with the osteotomy.

The osteotomy

Using a specialized oscillating saw blade, the surgeon makes a curved (arcuate) cut through the proximal tibia at the level of the tibial plateau.

The radius of this cut is determined by the pre-operative planning.

Rotation

The cut bone segment (containing the tibial plateau) is rotated backward (caudally) by the calculated amount to achieve the target TPA.

VCA Animal Hospitals confirms: the top section of the tibia is rotated backward until deemed appropriately level -- typically 2 to 14 degrees, with 5 degrees as the ideal angle.

Plate fixation

A TPLO plate (a contoured locking plate) is secured to the tibia across the osteotomy using locking screws. The plate holds the rotated tibial plateau in position while the bone heals.

Closure

The joint capsule, fascia, subcutaneous tissue, and skin are closed in layers. The incision is bandaged.

Success rate and outcomes

RCVS Canine Cruciate Registry confirms: TPLO has a 90 to 95% success rate, with 90 to 95% of dogs regaining complete or near-complete function; 93% of owners reporting satisfaction at 12 months.

A 2013 study found that TPLO patients achieved 93% restoration of limb function at 1 year.

TPLO produces better long-term outcomes than lateral suture stabilization in most studies of large dogs, and similar long-term outcomes to TTA in comparable patient populations.

RCVS confirms: all dogs with CCL rupture are expected to develop at least some osteoarthritis, but this is reduced or delayed in dogs that have had surgical stabilization.

Recovery overview

• Weeks 0 to 2: crate rest, 5-minute bathroom leash walks only, e-collar on at all times
• Weeks 2 to 6: graduated leash walk increase, passive range-of-motion exercises
• Week 6: radiographic assessment of bone healing; activity increase if healing is progressing
• Weeks 8 to 12: final radiographic confirmation of bone healing; activity restrictions lifted if healing is confirmed
• Months 3 to 6: progressive return to full activity; muscle recovery continues

For the full recovery guide, see what to expect after TPLO surgery in dogs. For the surgery comparisons, see TPLO vs CBLO vs TTA: a guide to cruciate surgery options.

For preparation, see preparing for your dog's TPLO surgery. For the signs that TPLO may be needed, see 13 signs your dog may need TPLO surgery.

Frequently asked questions

Is TPLO the only surgery for CCL rupture in dogs?

No. The main alternatives are lateral suture stabilization (extracapsular repair), TTA (tibial tuberosity advancement), and CBLO (CORA-based leveling osteotomy). Lateral suture achieves good outcomes in dogs under approximately 35 pounds.

TTA produces similar long-term outcomes to TPLO in appropriately selected dogs. CBLO is used mainly for immature dogs and revision surgery cases.

Can a dog live without surgery for CCL rupture?

Small dogs (under 10 to 15 kg) sometimes stabilize adequately with conservative management (strict rest, weight management, joint support).

For most dogs over 15 kg, conservative management does not restore normal joint stability and the dog remains in pain with progressive arthritis.

Surgery is strongly recommended for most medium and large dogs.

How long does TPLO surgery take?

The procedure typically takes 1.5 to 2 hours. Bilateral simultaneous TPLO takes 3 to 4 hours.

Does the TPLO plate stay in permanently?

Yes, in most cases. The plate is not routinely removed after the osteotomy heals. It is removed if it causes complications (infection, implant irritation, failure).

What is the cost of TPLO surgery?

TPLO typically costs $3,500 to $6,000 per stifle depending on the facility, surgeon, geographic location, and the dog's size.

This typically includes the surgical procedure, anesthesia, hospitalization, implants, and the immediate post-operative period.

Resources

• RCVS Canine Cruciate Registry. Tibial Plateau Levelling Osteotomy (TPLO). rcvsknowledge.org
• VCA Animal Hospitals. TPLO. vcahospitals.com
• Dispomed. TPLO Surgery in Dogs: Success Rates and Alternatives. dispomed.com
• ACVS. Cranial Cruciate Ligament Disease. acvs.org

Physical therapy after TPLO begins on day one -- not after the bone heals. The question is not whether to start, but which type is appropriate at each stage.

Early rehabilitation is about pain management and encouraging weight bearing. Later rehabilitation is about restoring muscle mass, range of motion, and functional strength.

The timing for each phase is defined by healing biology, not by how the dog appears to feel.

Quick answer: Physical therapy begins on day 1 with leash walks and cold therapy. Passive range-of-motion exercises start at days 3 to 5. Hydrotherapy begins at weeks 2 to 3. Strengthening increases from weeks 4 to 8. Plans complete by weeks 8 to 12; full recovery takes 4 to 6 months after TPLO surgery.

Key takeaways

• Leash walking begins within 24 hours of surgery: TPLO Info confirms short 5-minute walks multiple times daily from day 1; early weight bearing maintains muscle mass and bone healing
• Passive range-of-motion exercises start at days 3 to 5: gentle manual flexion and extension of the stifle maintains joint mobility during restricted activity
• Hydrotherapy can begin around weeks 2 to 3 after incision healing is confirmed; underwater treadmill provides resistance and buoyancy simultaneously
• Professional rehabilitation offers advantages over at-home protocols: certified therapists provide therapeutic laser, TENS, underwater treadmill, and individualized monitoring
• Strengthening exercises begin around weeks 3 to 4 when the dog consistently bears weight; cavaletti poles, weight-shifting, and balance work rebuild lost muscle
• Free running and high-impact activities resume only after radiographic bone healing confirmation at weeks 8 to 12; earlier return risks osteotomy failure

Phase 1: immediate post-surgical period (days 1 to 14)

What begins immediately

Leash walking: begins within 24 hours of surgery. TPLO Info confirms short 5-minute leash walks multiple times daily from day one. These walks are bathroom trips only in the first week -- not exercise walks. The goal is to maintain the neural stimulus for weight bearing and to prevent the complete disuse that leads to rapid muscle atrophy.

Veterinary Partner VIN confirms: Phase 1 begins immediately after surgery; slow, controlled leash walks 3 to 4 times daily for 5 to 10 minutes are the primary activity.

Cold therapy (icing): ice applied to the incision site for 10 to 15 minutes after each walk during the first 3 to 5 days. TPLO Info recommends icing the incision directly for the first 3 to 5 days post-surgery. Cold therapy reduces local inflammation and pain, making the dog more comfortable and more likely to bear weight.

Edmonton Veterinary TPLO protocol confirms: time physical therapy exercises approximately 30 minutes after pain medications are given so the dog is most comfortable during exercise.

Passive range-of-motion exercises (days 3 to 5)

PROM exercises are gentle manual flexion and extension of the stifle joint. SustainableVet.org confirms: gentle passive exercises usually start within 3 to 5 days post-surgery.

How to perform PROM:

• Hold the thigh and lower leg, not the joint itself
• Slowly flex the stifle toward the chest (as far as comfortable without resistance)
• Slowly extend the stifle toward straight
• 5 to 10 repetitions, 2 to 3 times daily
• Never force the range -- stop at the point of resistance or discomfort

PROM maintains joint cartilage health, prevents fibrous tissue formation in the joint, and maintains range of motion during the period when the dog is resting.

Phase 2: early rehabilitation (weeks 2 to 4)

What begins at the 2-week recheck

The 2-week recheck confirms incision healing and reviews early recovery. If healing is proceeding normally, Phase 2 activities begin.

Increased leash walk duration: TPLO Info recommends increasing walk duration by up to 5 minutes per week from the 2-week baseline. Vetplayas confirms: by week 2, controlled leash walks should be extended to promote muscle strength and flexibility.

Hydrotherapy: SustainableVet.org and the Vetplayas recovery guide both confirm hydrotherapy can begin around week 2 to 3, once the incision is healed. Underwater treadmill therapy provides three simultaneous benefits:

• Buoyancy reduces joint loading while still requiring weight bearing
• Water resistance builds muscle without impact
• Warmth promotes circulation and reduces stiffness

Professional hydrotherapy (certified facility with underwater treadmill) is preferable to open-water swimming in the early phase -- controlled depth and therapist supervision improve safety.

Balance training (from week 3 to 4): TPLO Info confirms that once the dog is consistently bearing weight on the operated leg (typically around weeks 3 to 4), weight-shifting exercises can begin. Stand the dog on a non-slip surface and gently push the hindquarters from side to side -- the dog responds by shifting weight to maintain balance, which activates the hip stabilizers.

Phase 3: progressive strengthening (weeks 4 to 8)

Core strengthening and higher-level exercises

Veterinary Partner VIN confirms: Phase 2 (which overlaps with what most owners call weeks 3 to 8) involves core strengthening once sufficient basic strength is achieved.

Activities that begin in weeks 4 to 8 (vet-directed):

• Cavaletti poles: slow stepping over low poles placed on the ground; encourages deliberate limb placement and hip flexion
• Hill walking: gentle inclines on a leash (begin by week 6 in most protocols)
• Sit-to-stand exercises: transitions from sitting to standing strengthen hip extensors
• Balance board or wobble board exercises: builds proprioception and stabilizer strength

WM-Referrals TPLO physiotherapy protocol confirms: start hydrotherapy, cavaletti poles, and balance board work at week 6; progress to 30 to 40 minute walks by this phase.

6-week radiograph checkpoint: activity level in Phase 3 is calibrated against radiographic findings at the 6-week visit. If bone healing is progressing well, activities increase as above. If healing is delayed, Phase 3 activities are deferred.

Phase 4: return to function (weeks 8 to 12 and beyond)

Radiographic confirmation at 8 to 12 weeks

SustainableVet.org confirms: most structured plans complete within 8 to 12 weeks. By 4 to 6 months, most dogs regain full mobility including running and playing.

After the 12-week radiograph confirms bone healing:

• Progressive jogging on leash
• Longer off-leash exploration in controlled environments
• Return to normal activity for most dogs
• Athletes and working dogs continue structured rehab for 4 to 6 months

Professional rehabilitation vs. at-home protocols

When professional rehab is recommended

TPLO Info confirms: ideally every dog would follow up with a rehabilitation therapist so a doctor can develop an individualized protocol. Professional rehabilitation is particularly beneficial when:

• The dog is slow to bear weight
• Significant muscle atrophy is present at the 6-week recheck
• The dog is a working dog, sports dog, or agility competitor
• Progress has stalled at any phase of recovery

What professionals offer

Certified canine rehabilitation therapists (CCRPs) provide:

• Therapeutic laser (reduces inflammation, promotes tissue healing)
• Transcutaneous electrical nerve stimulation (TENS) for pain management
• Controlled underwater treadmill protocols
• Individualized exercise prescription based on daily assessment
• Early detection of complications (inappropriate gait patterns, asymmetric muscle development)

At-home protocols

At-home rehabilitation following the vet's guidelines is appropriate for most dogs.

The core elements -- short leash walks, PROM exercises, cold therapy, gradual activity increase, and balance work -- are all achievable at home with proper instruction.

For the recovery timeline overview, see what to expect after TPLO surgery in dogs. For PROM exercises specifically, see PROM exercises for dogs after TPLO surgery.

For range-of-motion exercises, see TPLO range-of-motion exercises for dogs. For rehab exercise detail, see TPLO rehab exercises for dogs.

Frequently asked questions

Can physical therapy start before the incision heals?

Yes -- the early elements (leash walking, cold therapy, and PROM exercises) begin before the incision is fully healed, typically from day 1 to 5 onward.

Hydrotherapy and balance work require incision healing confirmation, typically at the 2-week recheck.

Is professional physical therapy necessary for TPLO recovery?

Not strictly necessary for all dogs, but beneficial for those recovering slowly, those with significant muscle atrophy, and working or sport dogs. At-home protocols following vet instructions are appropriate for most dogs.

Professional rehab adds precision and advanced modalities.

How often should my dog have hydrotherapy sessions?

Typically 1 to 3 times per week during the active rehabilitation phase (weeks 2 to 8). Frequency depends on the dog's response, transportation constraints, and cost.

Each session's therapeutic benefit persists for several days, so daily hydrotherapy is not required.

What if my dog refuses to use the leg despite physical therapy?

Persistent non-weight-bearing beyond 3 to 4 weeks warrants veterinary investigation. Possible causes include inadequate pain control, implant complication, late meniscal tear, or infection.

Physical therapy cannot proceed normally until the underlying cause of non-weight-bearing is addressed.

Can I use a swimming pool at home for hydrotherapy?

Only with vet guidance and with the dog supervised at all times. Open water swimming is less controlled than an underwater treadmill.

Risks include the dog launching themselves off the pool edge (impact on landing), inability to control depth, and water contamination of the incision if not fully healed.

Resources

• TPLO Info. Rehabilitation After TPLO Surgery. tploinfo.com
• Veterinary Partner VIN. Physical Rehabilitation of Dogs Following TPLO. veterinarypartner.vin.com
• SustainableVet. TPLO Rehab Exercises for Dogs. sustainablevet.org
• WM Referrals. Post-operative Rehabilitation After TPLO. wm-referrals.com

CCL rupture in dogs is not the same injury as ACL rupture in humans.

In humans, the anterior cruciate ligament typically tears during sudden trauma a pivoting fall on a ski slope, a tackle on a football field.

In dogs, the same ligament almost always fails through slow, progressive degeneration that began months or years before the day the dog comes in lame.

Understanding why the canine CCL fails and which dogs are most at risk is essential for prevention strategies and for recognizing early warning signs.

Quick answer: The canine CCL fails through progressive degeneration, not sudden trauma. Key risk factors are breed, obesity, poor fitness, tibial slope, and genetics. At least 50% of dogs that rupture one CCL will rupture the other within 1 to 2 years.

Key takeaways

• CCL rupture results from degeneration, not trauma: ACVS confirms slow, progressive degeneration rather than acute injury to a healthy ligament
• Obesity is the most modifiable risk factor: excess weight increases compressive and shear forces on the CCL with every step
• High-risk breeds include Labrador, Rottweiler, Newfoundland, Mastiff, and Akita: genetic inheritance has been demonstrated in Newfoundlands and Labradors
• Partial tears almost always progress to complete rupture: ACVS confirms this and notes progression is the rule, not the exception
• At least 50% of dogs rupture the opposite CCL within 1 to 2 years of the first rupture
• Neuter status increases CCL risk: spayed and neutered dogs show higher rates in multiple studies

Why dog CCL disease differs from human ACL injury

Colorado State University: "In humans, trauma (such as skiing, football, or soccer injuries) is the most common reason for injury of the ACL.

This 'traumatic' rupture can happen in dogs but is quite rare."

CSU: "Most commonly, CCLD is caused by a combination of many factors, including aging of the ligament (degeneration), obesity, poor physical condition, conformation, and breed."

In humans, a healthy ACL tears from a single high-energy event. In dogs, the ligament is already weakened before it ruptures.

The moment of obvious lameness is the endpoint of a months-long degenerative process.

ACVS: ligament rupture is "the result of subtle, slow degeneration that has been taking place over a period of time rather than the result of sudden trauma to an otherwise healthy ligament."

Fitzpatrick Referrals: "In the vast majority of dogs, the CrCL ruptures as a result of long-term degeneration, whereby the fibres weaken and fray over time, losing their structure and function."

The main causes and risk factors

Degeneration (aging and immune-mediated)

The underlying degenerative process in CCL disease involves progressive breakdown of collagen fibers within the ligament.

PMC (Cranial Cruciate Ligament Rupture Review): "The structural weakening of this joint due to the progressive degeneration of the ligament is the most accredited etiopathogenetic hypothesis."

The degeneration appears to involve both mechanical fatigue and immune-mediated inflammatory processes within the joint.

Synovitis (joint inflammation) often precedes complete rupture and may be detected during veterinary examination before full failure occurs.

Breed and genetics

ACVS: "Certain dog breeds are known to have a higher incidence: Rottweiler, Newfoundland, Staffordshire Terrier, Mastiff, Akita, Saint Bernard, Chesapeake Bay Retriever, and Labrador Retriever."

ACVS: "A genetic mode of inheritance has been shown for Newfoundlands and Labrador Retrievers."

Fitzpatrick Referrals: "Genetic factors are likely very important, with certain breeds being predisposed including Labradors, Rottweilers, Boxers, West Highland White Terriers, and Newfoundlands."

Breeds with low CCL disease incidence include Greyhounds, Dachshunds, Basset Hounds, and Old English Sheepdogs.

Fitzpatrick: "Supporting evidence for a genetic cause was obtained by assessment of family lines and the knowledge that many animals rupture both knees relatively early in life."

Obesity

ACVS: "Poor physical body condition and excessive body weight are risk factors for the development of CrCLD. Both of these factors can be influenced by pet owners."

PMC: "A predisposing factor is obesity, in which the concentrations of circulating inflammatory mediators increase, such as the concentrations of pro-inflammatory adipokines released from adipose tissue, which may contribute to degenerative phenomena."

Obesity matters in two ways: it increases the mechanical load on the CCL with every step, and it elevates systemic inflammation, which accelerates ligament degeneration.

A dog 10% overweight places significantly more stress on both stifle joints with every stride.

Tibial plateau angle (conformation)

The tibial plateau is the top surface of the tibia. In dogs, it slopes caudally. During weight-bearing, this slope creates a cranial shear force on the tibia that the CCL normally resists.

Fitzpatrick: "Increased tibial plateau angle (backwards slope at the top of the tibia) may play a role" in CCL disease.

Dogs with steeper tibial plateau angles experience greater cranial thrust with each step, increasing CCL load.

This is why TPLO and CBLO surgery (which reduce the tibial plateau angle) neutralize the instability rather than replacing the torn ligament.

Neuter status

Multiple studies have found that spayed and neutered dogs have higher rates of CCL disease than intact dogs. The relationship is stronger in some breeds than others.

Proposed mechanisms include the loss of sex hormones that influence joint development and ligament maturation, longer bone growth periods in dogs neutered before skeletal maturity, and altered body composition.

Contralateral (opposite knee) risk

NCBi (Radiographic Risk Factors study): "Among dogs presented with unilateral CCL rupture, a large proportion will develop contralateral CCL rupture within 12 to 24 months of initial diagnosis.

This risk is in the range of 22 to 54% at 6 to 17 months of diagnosis."

CSU: "At least half of the dogs that have a cruciate ligament problem in one knee will likely, at some future time, develop a similar problem in the other knee."

This bilateral risk reflects the systemic nature of CCL degeneration both ligaments are affected by the same genetic, hormonal, and conformation factors.

Partial tears: the warning stage

The CCL typically does not rupture all at once. Partial tears are common and produce intermittent hind limb lameness that owners sometimes attribute to a sprain.

CSU: "Partial tearing of the CCL is common in dogs and frequently precedes complete rupture."

ACVS: "Partial tearing of the CCL is common in dogs and almost always progresses to a full tear over time."

A dog with a partial CCL tear that receives cage rest and returns to activity will almost always eventually progress to complete rupture.

Surgical intervention at the partial tear stage can be considered for active dogs, though evidence on whether it prevents eventual complete rupture is limited.

Signs of CCL disease

• Hind limb lameness, especially after exercise
• Sudden onset of non-weight-bearing on a back leg
• Stiffness when getting up, especially after rest
• Muscle atrophy on the affected hind limb
• Thickening on the inside of the knee joint (medial buttress)
• Positive cranial drawer test or tibial compression test on orthopedic examination

Can CCL tears be prevented?

Risk cannot be eliminated in predisposed breeds, but it can be reduced.

ACVS: "Consistent physical conditioning with regular activity and close monitoring of food intake to maintain a lean body mass is advisable."

Evidence-based prevention strategies:

• Maintain healthy body weight (most impactful modifiable factor)
• Consistent, regular exercise rather than intermittent intense activity
• Avoid sudden load increases (the "weekend warrior" pattern)
• Discuss neutering timing with your vet, particularly in high-risk breeds

For the surgical treatment of CCL rupture, see CBLO surgery in dogs: cost, recovery, and success rate. For the surgery vs. conservative management decision, see canine cruciate injuries: surgery vs. conservative management.

For meniscal injury that often accompanies CCL tears, see torn meniscus surgery cost in dogs. For when CCL disease requires specialist referral, see when to refer for orthopedic surgery.

Frequently asked questions

My dog tore its CCL running in the yard. Wasn't that traumatic?

The event may have looked sudden, but the ligament was almost certainly already degenerated.

ACVS: the rupture is "the result of subtle, slow degeneration... rather than sudden trauma to an otherwise healthy ligament." The yard run was the last straw, not the cause.

Which dog breeds are at highest risk for CCL tears?

ACVS identifies Rottweilers, Newfoundlands, Staffordshire Terriers, Mastiffs, Akitas, Saint Bernards, Chesapeake Bay Retrievers, and Labrador Retrievers as high-incidence breeds. Fitzpatrick Referrals adds Boxers and West Highland White Terriers.

Does obesity really make that much difference?

Yes. Obesity increases both mechanical load on the CCL and systemic inflammation via adipokines from fat tissue.

It is the most modifiable risk factor maintaining healthy body weight is the single most impactful thing an owner can do for CCL disease prevention.

My dog had surgery on one knee. How long before the other goes?

NCBi data: the risk of contralateral CCL rupture is 22 to 54% within 6 to 17 months of the first diagnosis. Monitoring the other knee closely after the first diagnosis is important.

Maintaining lean body weight and avoiding abrupt increases in activity are the main protective strategies.

Can a dog with a partial CCL tear be managed without surgery?

Conservative management (rest, weight loss, physical therapy) may be attempted for partial tears, particularly in small dogs. But ACVS states partial tears "almost always progress to a full tear over time."

Discuss with an orthopedic specialist whether surgery at the partial tear stage is appropriate for your dog.

What is the difference between CCL and ACL?

CCL (cranial cruciate ligament) is the correct term in dogs; ACL (anterior cruciate ligament) is the human equivalent. They are anatomically similar structures that stabilize the knee joint.

The key clinical difference: in humans, ACL tears are usually traumatic; in dogs, CCL tears are almost always degenerative.

Resources

• ACVS. Cranial Cruciate Ligament Disease. acvs.org
• CSU Veterinary Health System. Canine Cruciate Ligament Injury. vetmedbiosci.colostate.edu
• Fitzpatrick Referrals. Cruciate Ligament Disease or Injury. fitzpatrickreferrals.co.uk
• NCBi PMC. Radiographic Risk Factors for Contralateral Rupture in Dogs with Unilateral CCL Rupture. ncbi.nlm.nih.gov
• PMC. Cranial Cruciate Ligament Rupture in Dogs: Review on Biomechanics, Etiopathogenetic Factors and Rehabilitation. ncbi.nlm.nih.gov