It is common to notice changes in a dog's urination pattern in the first 24 to 48 hours after TPLO surgery.

Most of these changes are temporary and related to the effects of anesthesia, pain medications, and reduced mobility.

However, not urinating at all for more than 12 to 24 hours is a clinical concern that requires prompt veterinary contact.

Quick answer: Reduced urination in the first 12 to 24 hours after TPLO is usually caused by anesthesia effects, opioid medications, pain, or stress. Contact your vet immediately if your dog has not urinated within 12 hours post-surgery, or if you observe straining, vocalization, or abdominal distension.

Key takeaways

• Reduced urination in the first 12 to 24 hours is normal: anesthesia suppresses bladder awareness and opioids reduce the sensation of fullness
• Contact your vet if no urination occurs within 12 hours post-surgery: this is the critical threshold, per published veterinary guidance do not wait
• Straining, vocalizing, or abdominal swelling requires same-day veterinary evaluation: these signs suggest urinary retention requiring catheterization
• Opioid pain medications are the most common pharmacological cause: they reduce bladder filling sensation and sphincter tone in some dogs
• Surgical catheterization during the procedure may temporarily affect urination for 12 to 24 hours after catheter removal
• Increased water intake without urination is particularly concerning: it suggests the dog is producing urine but cannot eliminate it a potential retention emergency

Why dogs may not urinate normally after TPLO

Anesthesia effects

General anesthesia suppresses the entire nervous system, including the neural pathways that signal bladder fullness and initiate voiding.

As anesthetic agents clear over the first 12 to 24 hours, normal bladder signaling gradually returns.

Most dogs produce less urine during anesthesia because of reduced blood pressure and fluid redistribution.

When fluid therapy resumes and hydration normalizes after surgery, urine production increases but the dog must also have recovered enough neurological function to void normally.

Opioid pain medications

Opioid analgesics (hydromorphone, morphine, buprenorphine) prescribed after TPLO affect urination in two main ways.

They reduce the perception of bladder fullness, so the dog does not signal readiness to urinate as promptly as usual.

In some dogs they also increase urethral sphincter tone, making voiding more difficult.

JustAnswer veterinary consultation confirms: opioids can cause urinary retention by relaxing or altering bladder muscles, making it hard for the dog to pee.

This effect is temporary and typically resolves as opioid dosing decreases over the first 48 to 72 hours.

Pain and reluctance to posture

Urination requires the dog to posture squatting or lifting a leg both of which require hindlimb use and core stability that are painful in the first days after TPLO.

A dog that finds posturing too painful may suppress the urge to urinate or produce only small amounts.

Providing a non-slip surface, a low slung outdoor space (not steps or slopes), and supporting the dog with a belly sling during outdoor trips reduces posturing pain and encourages normal urination.

Surgical catheterization

A urinary catheter is often placed during TPLO surgery to drain the bladder, keep the surgical field dry, and prevent accidents during the procedure.

After catheter removal, some dogs take 12 to 24 hours to resume normal voiding patterns as the urethra recovers from catheter placement and the bladder regains normal tone.

Stress and unfamiliar environment

Dogs in pain, in an unfamiliar post-surgical environment, and wearing an E-collar may suppress urination due to stress.

Stress-related urinary suppression is temporary and usually resolves as the dog settles into the home recovery environment.

Normal urination expectations after TPLO

Most dogs urinate at least once within 6 to 12 hours of returning home from surgery. By 24 hours, most dogs have urinated multiple times.

The SustainableVet.org dog-not-peeing guide confirms: if your dog does not pee within 24 hours post-surgery, contact your veterinarian immediately to rule out complications.

The published veterinary guidance for emergency contact is: no urination within 12 hours post-surgery contact your vet.

Signs that require immediate veterinary contact

Contact your veterinarian same-day or go to an emergency clinic if you observe:

No urination at all for 12 or more hours after surgery: this is the key threshold do not wait to see if it resolves

Straining or crying during urination attempts: the dog is trying to urinate but cannot produce a stream classic urinary retention sign

Abdominal distension: the belly feels full or tense; this suggests a distended bladder (urinary retention emergency)

Drinking water but producing no urine: urine is being produced but cannot be eliminated urgent

Vomiting or lethargy alongside no urination: systemic signs accompanying urinary retention indicate a more serious emergency

Urinary retention: what happens and how it is treated

Urinary retention means the bladder cannot empty. The bladder fills progressively and becomes painful, distended, and eventually at risk of rupture if unrelieved. Prolonged retention also causes back-pressure on the kidneys.

Treatment depends on the cause:

• Catheterization: gentle placement of a urinary catheter to drain the bladder provides immediate relief and allows the bladder to recover normal tone
• Pain management adjustment: if opioid-induced retention is suspected, the analgesic protocol may be modified
• Bethanechol: a parasympathomimetic drug that stimulates bladder contraction; sometimes used in dogs with neurogenic urinary retention
• Urinalysis and culture: if infection is suspected alongside retention

Home care to encourage urination

• Scheduled outdoor trips every 2 to 4 hours for the first 24 to 48 hours
• Non-slip surface outdoors pain and weakness increase slipping risk
• Gentle belly-sling support to reduce posturing pain (fold a large towel under the belly and lift slightly)
• Quiet, calm outdoor environment stressed dogs suppress urination
• Adequate pain control contact your vet if your dog is vocalizing or reluctant to move; these are signs pain medication is insufficient
• Monitor and record each urination: time, approximate volume, any straining or discomfort

For the related incontinence guide (opposite problem), see dog incontinence after TPLO surgery: causes and care. For the post-surgical pain guide, see dog whining after TPLO surgery: causes and care.

For the full recovery guide, see what to expect after TPLO surgery in dogs. For the monitoring guide during early recovery, see post-operative care mistakes increasing TPLO infection risk.

Frequently asked questions

How long after TPLO surgery should my dog urinate?

Most dogs urinate within 6 to 12 hours of returning home from surgery. Contact your veterinarian if no urination has occurred within 12 hours.

Do not wait for the 24-hour mark if the dog is straining, vocalizing, or appears uncomfortable.

My dog is drinking water but not peeing at all. Is this an emergency?

Yes. A dog that is drinking and producing urine but cannot eliminate it (retention) needs same-day veterinary evaluation. A distended bladder is painful and can rupture.

Do not manage this at home contact your vet immediately.

Can opioid pain medications cause urinary retention?

Yes. Opioids are a recognized cause of urinary retention in both humans and dogs.

If your dog was urinating normally before surgery and stops after receiving opioid medications, this is likely a contributing factor.

Contact your vet the analgesic protocol may be modified without eliminating pain management.

What does a catheter placement during surgery do to urination afterward?

Urinary catheters are placed during TPLO to drain the bladder and keep the surgical field dry.

After catheter removal, some dogs take 12 to 24 hours to resume normal voiding as the urethra recovers.

This is expected and not a cause for alarm, as long as the dog urinates within the normal timeframe.

Is it safe to give my dog extra water if they're not peeing?

Normal hydration is essential and should be maintained. Do not restrict water.

However, if the dog is drinking normally and still not producing urine, this increases the urgency of veterinary contact rather than reducing it.

Resources

• VCA Animal Hospitals. Tibial Plateau Leveling Osteotomy (TPLO) in Dogs. vcahospitals.com
• TPLO Info. Recovery FAQs. tploinfo.com
• PetMD. Urinary Retention in Dogs. petmd.com
• Midwest Veterinary Specialists. Post-Operative Care Following TPLO. midwestveterinaryspecialists.com

Before performing TPLO surgery, the veterinary surgeon selects the appropriate bone plate from a range of sizes specific to the implant system being used.

The plate size chart is the reference tool that guides this selection.

Choosing the correct plate is as important as the surgical technique itself an undersized plate risks mechanical failure, and an oversized plate may not fit the tibial anatomy correctly.

Quick answer: The TPLO plate size chart matches body weight and tibial bone dimensions to the appropriate implant. Arthrex plates range from 2.0 mm to 4.5 mm; Synthes covers a similar range. Tibial width is measured on preoperative radiographs and used alongside body weight to select the plate and screw configuration.

Key takeaways

• The plate size chart is a preoperative planning tool that matches body weight and bone dimensions to the appropriate implant
• Arthrex offers TPLO plates from 2.0 mm to 4.5 mm: the small sizes are purpose-designed for small breed anatomy, not scaled-down large plates
• Tibial width is measured on preoperative radiographs: a primary determinant of plate selection alongside body weight
• Plate selection is system-specific: Arthrex plates require Arthrex instruments and screws; Synthes requires Synthes-specific tools
• The plate is single-use sterile: a new plate must be available if a different size is needed intraoperatively
• Correct plate selection directly affects outcomes: undersized plates risk fatigue fracture; oversized plates cause soft tissue irritation

What the plate size chart does

The TPLO plate size chart is a lookup reference similar in function to the rotation chart and weight chart that are part of the Arthrex and Synthes TPLO planning systems.

It takes known inputs (primarily body weight and tibial dimensions measured on radiographs) and outputs the recommended plate size from the manufacturer's product range.

SustainableVet.org explains: a TPLO plate size chart is a reference guide used by veterinary surgeons to select the appropriate implant size for stabilizing the tibia after TPLO surgery.

Plates come in various lengths and hole numbers to fit different dog breeds and bone sizes.

The chart removes the guesswork from a decision that significantly affects the mechanical performance of the repair.

A plate that is correctly sized distributes load evenly across all screw holes and lies flush against the cortical bone surface, minimizing stress risers and soft tissue irritation.

Key variables in plate size selection

Body weight

Body weight is the primary initial filter. Heavier dogs generate higher joint forces and require larger, stiffer plates to withstand the loads applied during weight-bearing and normal activity.

General size categories used across Arthrex and Synthes product lines:

• Small breed (under 10 to 15 kg): 2.0 mm or 2.4 mm plates
• Medium breed (15 to 30 kg): 3.5 mm plates
• Large breed (30 to 50 kg): 3.5 mm or 4.5 mm plates
• Giant breed (over 50 kg): 4.5 mm plates; locking systems particularly important

These ranges are approximate and surgeon-dependent. The specific manufacturer chart values take precedence over general categories.

Tibial width and bone dimensions

The plate must span the osteotomy site with at least 2 screws proximal and 2 screws distal to the cut for adequate fixation.

The tibial width at the planned osteotomy level measured in millimeters on a mediolateral radiograph determines which plate length and screw configuration provides sufficient purchase without overhanging the bone margins.

Number of screw holes

Plates are available with different numbers of holes (typically 4, 5, or 6 holes for standard sizes).

More holes provide more screw fixation points, which is important in larger dogs or those expected to be highly active during recovery.

SustainableVet.org notes: plates come in various lengths and hole numbers to fit different dog breeds and bone sizes, allowing surgeons to select the configuration that best matches each individual patient's anatomy.

Arthrex TPLO plate system

Arthrex produces the most widely used TPLO locking plate system in the United States. The Arthrex TPLO Locking Plate System is designed with specific anatomical features to facilitate consistent plate placement.

From Arthrex Vet Systems documentation: the 2.0 mm and 2.4 mm TPLO locking plates are not simply shrunken versions of larger TPLO plates.

The smaller plates were purpose-designed for small breed bone anatomy.

Small dogs have proportionally different tibial geometry, and scaling down a large plate does not optimize screw angle or load distribution.

Arthrex's 4.5 mm plate incorporates a caudal tilt designed for improved screw purchase in the proximal tibial segment, with a proximal screw trajectory directed to avoid the osteotomy line.

This is an important design feature: screws that inadvertently cross the osteotomy reduce fixation quality and risk creating a stress concentration at the cut.

The Arthrex system includes an InternalBrace ligament augmentation option for dogs with severe stifle instability. This knotless lateral stabilization technique is not part of standard TPLO.

For the Arthrex plate overview, see Arthrex TPLO plate overview and use. For the Synthes plate overview, see Synthes TPLO plate overview and use.

How the plate size chart integrates with other planning tools

The plate size chart is used in concert with two other charts in the preoperative planning sequence:

Rotation chart: determines how many degrees the tibial segment must be rotated to achieve the target postoperative TPA of approximately 5 degrees. This is completed using the preoperative TPA measurement from radiographs.

Weight chart: guides post-operative weight-bearing expectations during rehabilitation.

All three charts together form the complete preoperative planning and post-operative monitoring framework. For the rotation chart, see Arthrex TPLO rotation chart explained.

For the weight chart, see Arthrex TPLO weight chart explained.

Why correct plate size matters

Mechanical adequacy: the plate must be strong enough to withstand the bending forces applied across the osteotomy during recovery typically equivalent to body weight or more during brief dynamic loading events (jumping down from a bed despite restrictions). An undersized plate risks fatigue fracture if the osteotomy takes longer to heal than expected.

Biological fit: the plate must lie flush against the bone surface. A plate that sits proud causes soft tissue irritation and can lead to the implant-associated pain and lameness that eventually requires plate removal.

Screw purchase quality: screws that are too short for the bone depth, or too long and penetrating the far cortex inappropriately, compromise fixation quality. Plate size selection is linked to the specific screw lengths that are compatible with each plate variant.

Frequently asked questions

Can the surgeon change the plate size during surgery?

Yes. If the preoperatively planned plate size does not fit correctly once the osteotomy is made and the bone is positioned, the surgeon may open a different plate size.

This is why surgical teams keep a range of plate sizes available in the sterile field or immediately accessible.

The plate is a single-use sterile item it cannot be resterilized if opened and unused.

Are Arthrex and Synthes plates interchangeable?

No. Each manufacturer's plates require that manufacturer's specific screws, instruments, and jigs.

Using Synthes screws in an Arthrex plate (or vice versa) risks stripped screw heads, incorrect screw purchase geometry, and compromised fixation. The systems are entirely separate.

How does the surgeon know which plate to order before surgery?

The surgeon measures the tibial width and records body weight at the preoperative planning appointment.

Based on these measurements and the manufacturer's size chart, a specific plate and screw set is ordered or identified from the implant inventory before surgery.

Is a larger plate always better for a big dog?

Not necessarily.

The plate must fit the tibial anatomy. A plate longer than the available cortical surface overhangs the bone, creating soft tissue irritation and stress concentration at the plate ends.

The goal is the smallest plate that provides adequate mechanical fixation for the dog's body weight and expected activity level.

What happens if the wrong plate size is used?

An undersized plate risks fatigue fracture under repetitive loading. An oversized plate may not conform to the bone surface, reducing screw fixation quality and potentially causing soft tissue irritation.

Plate failure or malposition requiring revision is a recognized complication of poor implant selection.

Resources

• Arthrex Vet Systems. TPLO Locking Plate System. arthrexvetsystems.com
• Arthrex Vet Systems. 4.5 mm TPLO Plates and Screws. arthrexvetsystems.com
• PMC. Influence of Fixation Systems on Complications After TPLO in Dogs Greater Than 45 kg. ncbi.nlm.nih.gov
• VCA Animal Hospitals. Tibial Plateau Leveling Osteotomy (TPLO) in Dogs. vcahospitals.com

When dogs suffer from cranial cruciate ligament (CCL) rupture, surgical options like CORA-Based Leveling Osteotomy (CBLO) and Tibial Plateau Leveling Osteotomy (TPLO) are common. Choosing the right surgery can be confusing for pet owners. This article explains the differences between CBLO and TPLO clearly.

Both surgeries aim to stabilize the knee and reduce pain, but they use different techniques. Understanding these can help you decide the best treatment for your dog. You will learn how each surgery works, their benefits, risks, and recovery expectations.

What is CORA-Based Leveling Osteotomy (CBLO)?

CBLO is a newer surgical method designed to correct the knee joint angle by cutting and rotating the tibia bone. It uses the Center of Rotation of Angulation (CORA) to plan the correction precisely. This technique aims to restore normal joint mechanics and reduce arthritis progression.

The surgery involves measuring the tibial plateau angle and calculating the exact bone cut needed. This precision helps improve joint stability and function after surgery.

• Precise correction planning: CBLO uses detailed imaging to calculate the exact bone cut angle, improving surgical accuracy and joint alignment.
• Restores joint mechanics: By correcting the tibial angle precisely, CBLO helps the knee function more naturally, reducing abnormal stresses.
• Reduces arthritis risk: Better joint alignment may slow arthritis development compared to other techniques.
• Suitable for various dogs: CBLO can be adapted for different breeds and sizes, making it versatile for many patients.

CBLO is gaining popularity because it focuses on restoring the knee’s natural biomechanics. This can lead to better long-term outcomes for dogs with CCL injuries.

What is Tibial Plateau Leveling Osteotomy (TPLO)?

TPLO is a well-established surgery that changes the slope of the tibial plateau to stabilize the knee without relying on ligament repair. It involves cutting the tibia and rotating the bone to a flatter angle. This reduces the forward thrust that causes instability in CCL injuries.

TPLO has been used for decades and is considered a gold standard for many surgeons treating CCL rupture. It is effective in restoring function and reducing pain.

• Changes tibial slope: TPLO flattens the tibial plateau angle to prevent the femur from sliding forward during movement.
• Improves joint stability: By altering bone geometry, TPLO stabilizes the knee without needing ligament reconstruction.
• Proven track record: TPLO has decades of clinical use with good success rates in many dog breeds.
• Requires specialized equipment: The surgery needs specific saws and plates designed for the procedure.

TPLO remains a trusted option for many veterinarians due to its consistent results and ability to restore mobility in affected dogs.

How do CBLO and TPLO differ in surgical technique?

Both CBLO and TPLO involve cutting and rotating the tibia, but their planning and goals differ. CBLO uses the CORA method for precise angle correction, while TPLO focuses on leveling the tibial plateau to a standard angle.

These differences affect how the bone is cut, rotated, and fixed with plates and screws during surgery.

• Planning approach: CBLO uses CORA calculations for individualized correction; TPLO uses a fixed target angle for leveling.
• Bone cut shape: CBLO often uses an angled cut based on CORA; TPLO uses a curved cut around the tibial plateau.
• Rotation amount: CBLO rotation varies by dog’s anatomy; TPLO rotation aims for a 5-degree tibial plateau slope.
• Implant fixation: Both use plates and screws, but implant design may differ based on osteotomy shape.

Understanding these technical differences helps surgeons choose the best method for each patient’s anatomy and needs.

What are the benefits of CBLO compared to TPLO?

CBLO offers several advantages due to its precise correction method. It aims to restore normal joint mechanics more closely than TPLO, which may improve long-term joint health.

These benefits can influence recovery speed, pain levels, and arthritis progression after surgery.

• Individualized correction: CBLO tailors the bone cut to each dog’s unique anatomy, potentially improving joint function.
• Potentially less arthritis: Better joint alignment may reduce abnormal wear and slow arthritis development.
• Preserves bone stock: CBLO may remove less bone compared to TPLO, preserving more natural structure.
• Improved biomechanics: Restoring the natural joint angle can lead to better limb use and comfort.

While CBLO is newer, early studies suggest it may offer improved outcomes for some dogs compared to TPLO.

What are the risks and complications of CBLO and TPLO?

Both surgeries carry risks common to orthopedic procedures, including infection, implant failure, and delayed healing. Some risks vary based on technique and patient factors.

Knowing these risks helps owners prepare and monitor their dogs after surgery.

• Infection risk: Both surgeries involve bone cuts and implants, which can become infected if not properly managed.
• Implant complications: Plates or screws may loosen or break, requiring revision surgery in some cases.
• Delayed bone healing: Healing time can vary, and some dogs may experience slower recovery.
• Postoperative pain: Both procedures cause pain that needs management with medication and care.

Choosing a skilled surgeon and following postoperative instructions reduce these risks significantly.

How do recovery and rehabilitation compare between CBLO and TPLO?

Recovery after CBLO and TPLO involves rest, controlled activity, and physical therapy. Both surgeries require careful management to ensure proper bone healing and joint function.

Rehabilitation protocols may differ slightly based on the surgery type and surgeon preference.

• Initial rest period: Both require strict rest for 6 to 8 weeks to allow bone healing without stress.
• Physical therapy: Controlled exercises help regain strength and range of motion gradually.
• Pain management: Medications and cold therapy reduce pain and swelling during recovery.
• Long-term outcome: Most dogs regain good limb function within 3 to 6 months post-surgery.

Following the veterinarian’s rehabilitation plan is crucial for a successful recovery regardless of the surgery chosen.

Which dogs are best suited for CBLO or TPLO?

Dog size, breed, age, and anatomy influence which surgery is most appropriate. Both CBLO and TPLO can treat CCL rupture effectively but may be better suited to different patients.

Veterinarians evaluate each dog’s knee anatomy and lifestyle before recommending surgery.

• Large breeds: TPLO has a long history of success in large and active breeds like Labradors and German Shepherds.
• Variable anatomy: CBLO’s precise correction suits dogs with unusual tibial angles or complex deformities.
• Older dogs: Both surgeries can be performed safely, but recovery may be slower in senior dogs.
• Activity level: Active dogs may benefit from the biomechanical advantages of CBLO or TPLO depending on anatomy.

Discussing your dog’s specific case with a veterinary surgeon helps determine the best surgical option.

Conclusion

Choosing between CORA-Based Leveling Osteotomy and TPLO depends on your dog’s anatomy, breed, and lifestyle. Both surgeries aim to stabilize the knee and reduce pain from cruciate ligament rupture.

CBLO offers precise correction tailored to the dog’s unique bone structure, potentially improving joint mechanics and reducing arthritis risk. TPLO is a proven, reliable surgery with decades of success in many breeds. Consulting your veterinarian will help you decide the best option for your dog’s health and recovery.

FAQs

What is the main difference between CBLO and TPLO?

CBLO uses precise angle correction based on the CORA method, while TPLO levels the tibial plateau to a fixed angle to stabilize the knee.

Is one surgery better for small dogs?

Both surgeries can be used in small dogs, but CBLO’s individualized correction may be more suitable for unusual bone shapes.

How long does recovery take after these surgeries?

Recovery typically takes 3 to 6 months, with strict rest and physical therapy essential for proper healing.

Are there risks of arthritis after CBLO or TPLO?

Both surgeries reduce arthritis risk by stabilizing the knee, but CBLO may better preserve joint mechanics, potentially slowing arthritis progression.

Can dogs return to normal activity after surgery?

Most dogs regain good limb function and return to normal activity levels with proper rehabilitation after either CBLO or TPLO.

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

Bruising after TPLO surgery in dogs is a common concern for many pet owners. TPLO, or Tibial Plateau Leveling Osteotomy, is a surgical procedure to stabilize a dog's knee after a cruciate ligament injury. After surgery, owners often notice bruising around the incision site or leg, which can be alarming.

This article explains why bruising happens after TPLO surgery, how to care for your dog during recovery, and when to contact your veterinarian. Understanding bruising helps you support your dog's healing process effectively.

Why Does Bruising Occur After TPLO Surgery in Dogs?

Bruising happens when blood vessels under the skin break and leak blood into surrounding tissues. After TPLO surgery, bruising is usually due to the trauma of surgery and tissue manipulation. The surgical area may show discoloration as part of normal healing.

It is important to recognize that some bruising is expected, but excessive or worsening bruising may indicate complications. Knowing the causes helps you monitor your dog’s recovery closely.

• Surgical trauma: The cutting and repositioning of bone and soft tissue during TPLO can cause small blood vessels to rupture, leading to bruising around the surgical site.
• Inflammation response: The body’s natural healing process causes inflammation, which can increase blood flow and cause visible bruising and swelling near the incision.
• Blood thinning medications: If your dog is on medications like aspirin or NSAIDs, these can increase bruising risk by affecting clotting mechanisms.
• Movement after surgery: Excessive activity or pressure on the leg soon after surgery can worsen bruising by disrupting healing tissues and blood vessels.

Understanding these causes helps you differentiate normal bruising from signs of complications that need veterinary attention.

What Does Normal Bruising Look Like After TPLO Surgery?

Normal bruising after TPLO surgery usually appears as a purple, blue, or reddish discoloration around the incision or leg. It often develops within 24 to 48 hours post-surgery and gradually fades over 1 to 2 weeks.

Knowing the typical appearance and timeline of bruising helps you track your dog’s healing and identify abnormal changes early.

• Color changes: Bruises typically start dark purple or blue, then change to green, yellow, and finally fade as healing progresses over days to weeks.
• Size and spread: Normal bruising is usually localized near the incision and does not spread extensively to other parts of the leg or body.
• Swelling presence: Mild swelling often accompanies bruising but should not cause severe discomfort or limb deformity.
• Pain level: Some tenderness is expected, but your dog should not show signs of severe pain or limping beyond normal post-surgical recovery.

Monitoring these signs helps ensure bruising is part of normal healing and not a sign of infection or bleeding complications.

How Should You Care for Bruising After TPLO Surgery?

Proper care reduces bruising severity and supports healing after TPLO surgery. Following your veterinarian’s instructions and providing gentle care helps your dog recover comfortably and safely.

Simple steps at home can minimize bruising and swelling while preventing complications.

• Rest and restricted activity: Limit your dog’s movement to prevent pressure on the surgical site and avoid worsening bruising or swelling.
• Cold compress application: Applying a cold pack wrapped in cloth for 10–15 minutes several times daily during the first 48 hours can reduce swelling and bruising.
• Proper bandage care: Keep any surgical bandages clean and dry, and follow your vet’s instructions on changing or removing them to avoid irritation.
• Medication adherence: Administer all prescribed painkillers and anti-inflammatory drugs exactly as directed to control pain and reduce inflammation.

Consistent care helps your dog heal faster and reduces the risk of bruising-related complications.

When Should You Be Concerned About Bruising After TPLO Surgery?

While bruising is normal, certain signs indicate that your dog may need urgent veterinary evaluation. Recognizing these warning signs early can prevent serious complications.

If you notice any of the following, contact your veterinarian promptly for advice or examination.

• Rapidly expanding bruises: Bruising that spreads quickly or becomes very large may signal active bleeding or hematoma formation requiring medical attention.
• Excessive swelling and heat: Swelling that worsens with warmth and redness around the incision could indicate infection or inflammation needing treatment.
• Severe pain or lameness: If your dog shows intense pain, refuses to bear weight, or has a limp worsening over time, this may suggest complications.
• Discharge or foul odor: Any pus, bleeding, or bad smell from the surgical site is a sign of infection and requires immediate veterinary care.

Early detection of problems helps ensure timely treatment and better recovery outcomes.

Can Bruising Affect Your Dog’s Recovery After TPLO Surgery?

Bruising itself usually does not affect the overall success of TPLO surgery if it is mild and managed properly. However, severe bruising or related complications can delay healing and cause discomfort.

Understanding the impact of bruising helps you provide better care and communicate effectively with your veterinarian during recovery.

• Minor bruising benefits: Mild bruising is a normal sign of healing and usually resolves without affecting joint stability or function.
• Severe bruising risks: Large bruises or hematomas can increase pain, limit mobility, and sometimes require drainage or additional treatment.
• Infection risk: Bruised tissue is more vulnerable to infection, so keeping the area clean and monitoring closely is essential.
• Physical therapy considerations: Bruising may limit early physical therapy, so adjusting rehabilitation plans based on your dog’s condition is important.

Working closely with your vet ensures bruising does not interfere with your dog’s full recovery and return to normal activity.

How Can You Prevent Bruising After TPLO Surgery in Dogs?

While some bruising is unavoidable due to surgery, certain steps can reduce its severity and support smooth healing. Prevention focuses on careful handling and following veterinary guidance.

Taking precautions before and after surgery helps protect your dog’s tissues and blood vessels from excessive damage.

• Pre-surgery health check: Ensuring your dog is healthy and not on blood-thinning medications before surgery reduces bruising risk.
• Gentle post-op handling: Avoid rough play, jumping, or excessive pressure on the leg during recovery to prevent new bruises.
• Follow medication instructions: Use prescribed drugs properly and avoid over-the-counter medications without vet approval to prevent clotting issues.
• Regular veterinary follow-up: Attend all scheduled check-ups so your vet can monitor healing and address bruising or other concerns early.

Prevention and careful management promote a safer, faster recovery with minimal bruising complications.

Conclusion

Bruising after TPLO surgery in dogs is a common and usually normal part of the healing process. It results from surgical trauma and inflammation, appearing as discoloration near the incision site. Mild bruising typically resolves within two weeks without affecting recovery.

Proper care, including rest, cold compresses, and medication adherence, helps reduce bruising and supports healing. However, owners should watch for signs of excessive bruising, swelling, pain, or infection and contact their veterinarian promptly if these occur. Understanding bruising after TPLO surgery allows you to care for your dog confidently and ensure a smooth recovery.

FAQs

Is bruising after TPLO surgery normal for all dogs?

Yes, mild bruising is common after TPLO surgery due to tissue trauma and inflammation. However, the amount varies by individual and surgical factors.

How long does bruising last after TPLO surgery?

Bruising usually appears within 1–2 days after surgery and fades over 1 to 2 weeks as the tissues heal naturally.

Can I use cold packs on my dog’s bruising after surgery?

Yes, applying cold compresses wrapped in cloth for 10–15 minutes several times daily during the first 48 hours helps reduce swelling and bruising.

When should I call the vet about bruising after TPLO?

Contact your vet if bruising spreads rapidly, swelling worsens, pain is severe, or if there is discharge or foul odor from the incision.

Does bruising affect my dog’s ability to walk after TPLO surgery?

Mild bruising usually does not affect walking, but severe bruising or pain may cause limping and require veterinary evaluation.

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