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

The Modified Maquet Procedure (MMP) is an evolution of the Tibial Tuberosity Advancement (TTA) that uses a titanium foam wedge instead of a cage to advance the tibial tuberosity.

It has been positioned as a less invasive, faster-to-perform alternative to TPLO for dogs with CCL rupture.

Published clinical evidence shows both procedures produce good outcomes, with TPLO demonstrating a slight advantage in objective gait analysis at 3 months.

Quick answer: A prospective randomized study found TPLO achieves 93.9% of normal peak vertical force vs 89.4% for MMP at 6 months — no significant difference in complications or OA progression. MMP is less invasive, faster, and generally less expensive. Both are appropriate for medium-to-large breed dogs.

Key takeaways

• TPLO achieves 93.9% of normal ground reaction force at 6 months vs 89.4% for MMP — numerically superior but not statistically significant
• No significant difference in major complications or OA progression was found between TPLO and MMP in the comparative study
• MMP is less invasive and faster to perform: a titanium foam wedge and partial osteotomy instead of TPLO's full proximal tibial cut
• MMP is generally less expensive than TPLO: shorter surgical time and different implant costs reduce the procedure price
• Early partial weight-bearing may occur sooner after MMP due to less invasive fixation and the partial osteotomy
• TPLO has a much larger evidence base: 25+ years of data vs limited MMP evidence

How each procedure works

TPLO (Tibial Plateau Leveling Osteotomy)

TPLO addresses CCL rupture by making a curved osteotomy through the proximal tibia and rotating the tibial plateau to approximately 5 degrees.

This changes joint biomechanics so the stifle is stable during weight-bearing without a functioning CCL. The osteotomy is held in place with a bone plate and screws.

Modified Maquet Procedure (MMP)

MMP is an adaptation of TTA in which the tibial tuberosity is advanced cranially by making a partial osteotomy in the tibial crest.

A porous titanium foam wedge is inserted into the gap and a fixation staple holds the construct in position.

The cranial advancement of the tuberosity repositions the patellar tendon to neutralize the cranial thrust that occurs in the CCL-deficient stifle the same biomechanical principle as TTA, with different implants.

Animal Works Veterinary Surgery describes MMP as using improved implants and surgical techniques designed to reduce operating time and minimize complications compared to standard TTA.

The titanium foam wedge promotes bone ingrowth and healing without the need for a cage or plate system. Bone healing in the MMP osteotomy site is typically complete at 90 days radiographically.

Clinical evidence: TPLO vs MMP

Primary comparative study

PubMed (prospective randomized controlled study, 61 dogs, 76 joints): dogs were treated with TPLO (n=30, 41 joints) or MMP (n=31, 35 joints) and compared with healthy controls.

Outcomes were assessed by clinical examination, radiography, and treadmill force plate gait analysis at 6 weeks, 3 months, and 6 months.

Results at 6 months:

• TPLO: 93.9% of normal peak vertical force (PVF), 85.9% of normal vertical impulse (VI)
• MMP: 89.4% of normal PVF, 79.9% of normal VI

At 3 months, significantly more TPLO patients were within the reference range for healthy dogs on peak vertical force. By 6 months, the difference was not statistically significant.

No significant difference was found in major complications or OA progression at any time point.

Conclusion from the study: "Although no significant differences were found between the surgical methods, TPLO patients showed superiority with regard to clinical outcome."

MMP standalone study

PMC (35 dogs, unilateral CCL rupture, MMP): significant improvement in ground reaction forces at all time intervals. At 90 days, 54.2% of patients had a Symmetry Index suggesting normal gait.

Complete bone healing on radiographs at 90 days. Major complication rate: 8.5% (3 of 35), minor complication rate: 2.8%.

Practical comparison

Which dogs are best suited to each?

MMP is often chosen for:

• Medium and large breed dogs where a less invasive approach is preferred
• Cases where surgical time is a clinical consideration
• Practices experienced in MMP technique
• Dogs where cost is a factor

TPLO is typically recommended for:

• Large and giant breed dogs with high joint loads
• Dogs with steep tibial plateau angles where TPLO provides more precise biomechanical correction
• Cases where the largest available evidence base is preferred
• Surgeons with established TPLO experience

Animal Hospital of Adel notes that both surgeries are effective, with MMP being less invasive, less expensive, and quicker to perform.

Walkerville Vet's evidence review concludes that TPLO gives slightly better objective results and that MMP is expected to outperform standard TTA, though more evidence is needed.

For the full TPLO pros and cons, see TPLO surgery pros and cons for dogs. For the full alternatives overview, see alternatives to TPLO surgery for dogs.

Frequently asked questions

Is MMP as effective as TPLO for large dogs?

The evidence suggests TPLO has a slight advantage at 3 months, with equivalent outcomes by 6 months in the primary comparative study.

Most surgeons still prefer TPLO for large and giant breeds due to the larger evidence base and slightly superior short-term objective results. MMP is appropriate for many large dogs in experienced hands.

How much cheaper is MMP than TPLO?

MMP is generally less expensive than TPLO due to shorter surgical time and different implant costs. The specific difference varies by practice, region, and surgeon.

Ask your veterinarian for a direct cost comparison for your dog's specific case.

What is the complication rate for MMP compared to TPLO?

The MMP standalone study reported an 8.5% major complication rate. TPLO complication rates across the literature range from 14 to 34%.

However, these figures come from different study populations and settings, making direct comparison difficult. Neither procedure is free of risk.

How long does MMP recovery take compared to TPLO?

Both procedures require 8 to 12 weeks of restricted activity, though MMP's less invasive partial osteotomy may allow earlier partial weight-bearing in some dogs.

Full activity return for both procedures is typically at 4 to 6 months.

Can a dog have TPLO if MMP fails?

Yes. TPLO can be performed as a revision if MMP results in ongoing instability or poor function. The converse is less common.

Discuss revision options with an orthopedic specialist if your dog is not progressing as expected after MMP.

Resources

• PubMed. Outcome after Tibial Plateau Levelling Osteotomy and Modified Maquet Procedure in Dogs with CCL Rupture. pubmed.ncbi.nlm.nih.gov
• PMC. Outcome after Modified Maquet Procedure in Dogs: Force Plate Gait Analysis. ncbi.nlm.nih.gov
• Animal Works Veterinary Surgery. MMP vs TPLO. animalworksvets.com
• Dog Knee Injury. Modified Maquet Procedure (MMP Surgery) for Dogs. dogkneeinjury.com
• Walkerville Vet. Which ACL Surgery Is Best for Dogs? walkervillevet.com.au

Laser therapy also called photobiomodulation (PBMT) or low-level laser therapy (LLLT) is one of the most commonly offered adjunct treatments during TPLO recovery. Many specialist and rehabilitation centres include it routinely.

But the evidence for its benefits is more nuanced than the marketing suggests, and owners deserve an honest picture of what it does and does not reliably achieve.

Quick answer: Laser therapy after TPLO uses specific light wavelengths to reduce inflammation and support tissue healing. Evidence for early pain reduction is moderately supported; evidence for improved radiographic bone healing is weak. It is a safe adjunct but should not replace rehabilitation exercises, pain medication, or activity restriction.

Key takeaways

• Laser therapy reduces postoperative inflammation and may improve gait scores: a TPLO study found better hindlimb function at 8 weeks in treated dogs
• Evidence for improving radiographic bone healing is weak: three controlled studies found no statistically significant difference in healing time
• The 2024 AVMA randomized trial found no significant difference in CRP, weight bearing, pain scores, or SSI rates between PBMT and sham groups
• Sessions typically begin within the first few days of surgery and continue through the rehabilitation phase
• Laser therapy is safe with few contraindications: avoid eyes and active tumour sites; safe over the TPLO incision once closed
• It works best as part of a multimodal plan: exercise therapy and pain medication carry stronger evidence than laser alone

What laser therapy does

Laser therapy for dogs, also known as photobiomodulation, involves using specific wavelengths of light to penetrate tissues and promote cellular regeneration and healing. The laser light stimulates the production of ATP (adenosine triphosphate), enhancing cell repair and growth, reducing inflammation, and increasing blood circulation.

Photobiomodulation therapy has been shown to decrease inflammation, and increase analgesia, vascularization, and tissue healing after musculoskeletal injury or surgery.

The mechanism is photochemical: light energy at specific wavelengths (typically 630 to 980 nm) is absorbed by mitochondria.

This increases ATP production, modulates reactive oxygen species, and influences gene expression related to inflammation and healing.

The effects are local confined to the tissue depth the light reaches.

For post-TPLO use, the targets are: the surgical incision, the osteotomy site in the proximal tibia, and the surrounding periarticular soft tissues.

What the clinical evidence shows

Pain and function

Research following TPLO surgery showed that dogs receiving LLLT had better hindlimb function and gait scores at 8 weeks compared to controls. This is especially valuable in orthopedic recovery, where early weight-bearing can prevent muscle atrophy and joint stiffness.

In a controlled veterinary study, dogs with surgical incisions treated with laser therapy exhibited significantly less inflammatory cell infiltration and tissue necrosis within the first week post-op compared to untreated controls.

The 2024 randomized trial

54 client-owned dogs with CCL rupture undergoing unilateral TPLO surgery were enrolled. The study population was randomly assigned to either a treatment group receiving PBMT (24 dogs) or a control group (30 dogs). PBMT was performed immediately after induction, and at 6 hours, 24 hours, 48 hours, and 8 weeks postoperatively. Evaluation of CRP, pain scores, evidence of SSI, and percentage weight bearing were assessed at all time points.

The trial found the therapy showed promise but no statistically significant difference between groups on any primary outcome measure.

Bone healing

Three studies compared LLLT to a control and concluded that LLLT treatment did not make a significant difference in improving radiographic bone healing. The studies collectively provide weak evidence for this outcome.

This is an important distinction: laser therapy may support soft tissue healing, pain, and early function but it does not appear to accelerate the osteotomy healing visible on radiographs.

When to start and how often

Laser therapy uses focused light energy on the surgical site to support healing.

Most rehabilitation programmes begin laser therapy within the first 1 to 3 days after TPLO surgery, often at the surgical centre before discharge or at the first rehabilitation visit.

Typical post-TPLO laser protocol:

• Frequency: 3 to 5 sessions per week in the first 2 to 3 weeks
• Frequency: 1 to 2 sessions per week from weeks 3 to 8
• Session duration: 5 to 15 minutes depending on the laser system and dosing protocol
• Total sessions: typically 6 to 12 in the first 8-week recovery phase

The protocol varies by laser system, power output, and the individual patient's response.

Realistic expectations

Laser therapy is a useful adjunct in TPLO recovery. It is not a substitute for the treatments with stronger evidence: pain medication, activity restriction, and structured rehabilitation exercises.

Laser therapy could be particularly helpful for dogs with weight-bearing and gait issues while recovering from TPLO surgery after a cruciate injury.

Dogs with significant early swelling, wound sensitivity, or slow initial weight-bearing progress may benefit most. Dogs recovering well with standard multimodal analgesia and rehabilitation may show less measurable difference.

For the bone healing timeline that laser therapy supports during recovery, see TPLO bone healing time in dogs explained.

For the full recovery plan that laser therapy fits into, see 10 essential TPLO recovery tips for pet owners.

For the physical therapy that is the primary evidence-based adjunct, see when to start physical therapy after TPLO surgery.

For swelling management in the recovery period, see how long does swelling last after TPLO surgery.

Frequently asked questions

Is laser therapy safe over the TPLO incision?

Yes, once the incision is closed. Laser therapy is safe over sutured incisions and can be applied at the surgical site from the first post-operative day in most protocols.

Avoid direct application over open wounds or actively infected tissue.

How many laser sessions does a dog need after TPLO?

Typically 6 to 12 sessions across the first 8 weeks.

Start at 3 to 5 sessions per week for the first 2 to 3 weeks, tapering to 1 to 2 per week through the rehabilitation phase.

The exact protocol depends on the laser system and rehabilitation plan.

Does laser therapy replace pain medication after TPLO?

No. Laser therapy is an adjunct to pharmaceutical pain management, not a replacement. Post-TPLO pain management requires NSAIDs, and often gabapentin or other analgesics.

Laser therapy may reduce the pain burden and support earlier mobility but does not provide sufficient analgesia on its own.

Can I do laser therapy at home with a consumer device?

Consumer-grade red light therapy devices exist but operate at lower power densities than veterinary therapeutic lasers. The clinical evidence discussed in this article relates to veterinary-grade PBMT devices.

Home devices may offer some benefit but cannot replicate the dosing of professional equipment. Discuss with your rehabilitation veterinarian before purchasing.

Will laser therapy prevent my dog from needing more medication?

Possibly. If laser therapy reduces post-operative inflammation and pain, some dogs may need lower doses of pain medication or taper off sooner.

This should be guided by your veterinarian based on your dog's individual recovery trajectory.

Resources

• AVMA Journal. Photobiomodulation Therapy in Dogs Undergoing TPLO After Cranial Cruciate Ligament Rupture. avmajournals.avma.org
• Veterinary Evidence. Does LLLT Improve Radiographic Healing for Dogs with CCL Rupture Undergoing TPLO Surgery? veterinaryevidence.org
• AKC. Laser Therapy For Dogs: Uses, Side Effects, and Alternatives. akc.org
• Erchonia. Laser Therapy for Post-Surgical Recovery in Pets. erchonia.com

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

TPLO plate rejection is one of the less common but more serious complications that can follow tibial plateau leveling osteotomy surgery.

The term "rejection" is sometimes used loosely distinguishing between true immune-mediated rejection, infection, and implant loosening matters because the treatment differs significantly for each.

Quick answer: True TPLO plate rejection is rare — implants are highly biocompatible. It produces persistent swelling, heat, pain over the plate, and sometimes a draining tract. Infection produces identical symptoms. Contact your vet if lameness worsens or discharge appears weeks to months after surgery.

Key takeaways

• True immune-mediated plate rejection is rare: TPLO plates are made from highly biocompatible titanium or stainless steel
• Symptoms overlap significantly with infection: pain, swelling, heat, and discharge occur in both; bacterial culture distinguishes them
• Infection is the most common implant complication: TPLO infection rates range from 0.8 to 14.3%; true rejection is a small subset
• Signs typically appear weeks to months after surgery: worsening lameness after initial improvement is the classic red flag
• A draining tract (fistula) over the plate is a hallmark sign of implant-associated infection or rejection
• True rejection requires plate removal: once the osteotomy heals (at least 12 weeks), the plate is removed; bone heals without it

What is TPLO plate rejection?

The TPLO plate and screws are made from medical-grade titanium or stainless steel.

These materials are designed to be biologically inert the body should recognize them as neutral foreign material and wall them off without reaction.

Laguna Hills Animal Hospital explains that in some cases, the TPLO plate is rejected by the dog's body because it is perceived as a foreign object.

True immune-mediated rejection occurs when the immune system mounts an inflammatory response against the implant material itself. This is distinct from:

• Periprosthetic infection: bacteria colonize the implant surface and cause chronic infection around the plate; this is far more common than true rejection
• Mechanical failure: the plate bends, breaks, or screws loosen due to excessive force; this is a structural problem, not an immune reaction
• Normal post-surgical inflammation: expected in the first 2 to 3 weeks; should be improving, not worsening

In clinical practice, the distinction between true rejection and low-grade infection is often made by bacterial culture of the fluid or tissue at the site.

True aseptic rejection produces inflammation without bacterial growth; periprosthetic infection produces the same symptoms with positive cultures.

Symptoms of TPLO plate rejection

Dog Discoveries' veterinary reference describes plate rejection as: the knee becomes inflamed and sore around the plate, the dog feels constant pain and irritation, and the dog gets worse rather than better.

Signs of trouble are generally seen weeks to months after surgery rather than in the immediate post-operative period.

Key symptoms to monitor:

Worsening or persistent lameness: a dog that was improving and then regresses, or one whose lameness fails to improve beyond the expected baseline, is showing a key red flag. This is distinct from the expected early post-TPLO lameness that should be progressively improving week by week.

Localized swelling over the plate: visible or palpable swelling directly over the plate site (proximal medial tibia) that does not resolve with rest and is not reducing over time.

Warmth and heat at the surgical site: warmth beyond the first 2 to 3 post-operative weeks suggests ongoing inflammation.

Draining tract (fistula): a small hole in the skin near the surgical site that produces persistent clear, bloody, or purulent discharge. This is a hallmark of implant-associated complications either infection or reaction. Vet Playas confirms persistent drainage or discharge, especially with a foul odor, may indicate infection or plate rejection.

Pain on palpation: the dog reacts to direct pressure over the plate site.

Failure to heal: the dog is not progressing as expected at radiographic rechecks; osteotomy bridging is delayed or absent.

How plate rejection is diagnosed

Clinical examination: systematic palpation of the plate site, assessment of lameness grade, and comparison to expected recovery trajectory.

Radiographs: assess osteotomy healing, implant position, screw integrity, and periimplant bone quality. Periprosthetic bone loss suggests infection or chronic reaction.

Culture and sensitivity: fluid or tissue from the surgical site is cultured to determine whether bacteria are present and which antibiotics are effective. Culture-negative inflammation supports true rejection; culture-positive results confirm infection.

Blood work: elevated inflammatory markers (C-reactive protein, white blood cell count) confirm systemic involvement.

Treatment

For infection (most common implant complication)

Culture-directed antibiotic therapy is initiated. If the osteotomy is not yet healed, the plate must remain in place removing the plate before the osteotomy heals causes the bone segments to lose support.

Targeted antibiotics and local wound management may control infection until healing is sufficient.

If the infection does not resolve with antibiotics, surgical debridement or implant removal (if the bone has healed) may be required.

For the full infection management guide, see TPLO plate infection signs and treatment.

For true aseptic rejection

Plate removal is the definitive treatment. Laguna Hills Animal Hospital confirms that the bone plate must remain in place for at least 12 weeks to allow the bone to heal.

Once healing is confirmed radiographically typically at 10 to 12 weeks the plate can be safely removed.

The bone does not require the plate long-term; it is a scaffold to hold the osteotomy while it heals.

When to contact your veterinarian

Contact your vet if:

• Lameness worsens or plateaus instead of progressively improving
• You notice new swelling, heat, or discharge at the surgical site weeks after surgery
• A draining tract appears at or near the incision
• Your dog shows signs of pain at the plate site on palpation
• Radiographs at rechecks show unexpected findings around the plate or screws

For the implant failure guide, see TPLO implant failure signs and causes. For the plate removal recovery guide, see TPLO plate removal recovery guide.

For the full complications reference, see 15 common complications after TPLO surgery in dogs. For the plate infection article with antibiotic treatment details, see TPLO plate infection signs and treatment.

For when the plate needs to come out due to infection, see when does a TPLO implant need to be removed due to infection.

Frequently asked questions

How common is TPLO plate rejection in dogs?

True immune-mediated rejection is uncommon. TPLO plates are manufactured from highly biocompatible titanium or stainless steel.

The more common implant complication is infection (0.8 to 14.3% of TPLO cases depending on the study), which produces similar symptoms to rejection.

Metal allergy or true rejection accounts for a small subset of these cases.

How do I know if it's plate rejection or infection?

The symptoms overlap significantly. Bacterial culture of fluid from the site distinguishes them: culture-positive means infection; culture-negative inflammation in the right clinical context suggests true rejection.

Both require veterinary evaluation do not attempt to manage either at home.

Can the plate stay in if my dog is rejecting it?

No. If true rejection is diagnosed and the plate is causing ongoing inflammation, it must be removed once the osteotomy has healed sufficiently.

Most dogs do not require the plate after 10 to 12 weeks once the bone has consolidated. Plate removal is a less complex procedure than the original TPLO.

Will my dog need another surgery if the plate is rejected?

Plate removal surgery is typically required if true rejection is confirmed and the osteotomy has healed. This is less invasive than the original TPLO.

In most cases the dog recovers well after plate removal, and long-term outcomes are good.

Can rejection be prevented?

Pre-surgical screening for metal sensitivities can help select the best implant material. Strict aseptic technique during surgery minimizes infection that can mimic rejection.

Activity restriction during recovery reduces mechanical stress on the implant that increases complication risk.

Resources

• Dog Discoveries. Signs of TPLO Plate Rejection in Dogs. dogdiscoveries.com
• Vetplayas. Unveiling TPLO Plate Rejection Symptoms. vetplayas.com
• Laguna Hills Animal Hospital. TPLO Surgery Complications. lhah.com
• ACVS. Cranial Cruciate Ligament Disease. acvs.org

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