Joint Replacement Arthroplasty encompasses a range of advanced orthopedic procedures used to restore mobility, eliminate pain, and re-establish near-normal joint biomechanics in dogs with severe articular disease. Although Total Hip Replacement (THR) remains the most commonly performed arthroplasty, non-hip joint replacements—particularly elbow arthroplasty, unicompartmental resurfacing, and emerging stifle and shoulder solutions—represent essential options for carefully selected patients.
This page provides a comprehensive, surgeon-focused overview of non-hip arthroplasty systems, their indications, surgical principles, and postoperative expectations.

1. Overview and Principles of Joint Arthroplasty

Arthroplasty replaces or resurfaces diseased joint structures to achieve:

• Pain-free functional range of motion

• Restoration of load-bearing mechanics

• Reduction of degenerative joint disease progression

Modern veterinary arthroplasty relies on:

• Cementless biologic fixation (porous-coated metal encouraging osseointegration)

• Cemented fixation (PMMA) where bone quality is compromised

• Modular systems allowing tailored sizing and alignment

• Partial joint resurfacing where disease affects only one compartment

Non-hip joint replacements are indicated primarily when medical management, arthroscopy, corrective osteotomy, or arthrodesis cannot provide acceptable long-term function.

2. Elbow Arthroplasty

Canine elbow disease—particularly medial compartment disease (MCD) and end-stage osteoarthritis—represents one of the most challenging degenerative conditions to manage. Arthroplasty options include:

A. Unicompartmental Elbow Resurfacing (CUE – Canine Unicompartmental Elbow)

Indication:
Medial compartment disease with preserved lateral compartment cartilage.

Principle:
Instead of replacing the entire elbow, the CUE system resurfaces:

• Medial humeral condyle

• Medial coronoid process

This shifts loading forces to a synthetic, wear-resistant interface. CUE preserves joint anatomy, avoids extensive bone removal, and delays or prevents progression to end-stage OA.

Surgical Notes:

• Medial arthrotomy approach

• Removal of diseased cartilage and corrective contouring

• Press-fit implantation of humeral and ulnar components

• Requires precise alignment to avoid implant impingement

Outcomes:
Most dogs regain significant limb use, with high owner satisfaction at 12 months. Complications include implant wear, luxation of components, or persistent medial compartment pain.

B. Total Elbow Replacement (TER)

Indicated in end-stage elbow OA, chronic pain unresponsive to conservative management, or severe deformities incompatible with CUE.

Systems:
Various designs exist, including semi-constrained and hinged models.

Surgical Principles:

• Removal of the native trochlea and trochlear notch

• Alignment of humeral and ulnar components to replicate the elbow’s complex hinge-rotation biomechanics

• Bone cement or porous titanium surfaces for fixation

Challenges:

• Elbow kinematics are highly complex; minor malalignment causes severe dysfunction

• High complication rate compared to THR

• Risk of aseptic loosening, luxation, and infection

TER remains a highly specialized procedure performed in select cases.

3. Stifle (Knee) Arthroplasty

While TPLO, TTA, and extracapsular stabilization dominate surgical management of stifle disease, arthroplasty is gaining relevance for dogs with:

• Bicompartmental end-stage OA

• Severe trochlear or tibial plateau cartilage loss

• Failure of prior ligament or meniscal surgeries

A. Partial Stifle Resurfacing

Indications include focal cartilage defects or condylar wear.

Implants:
Contoured metallic resurfacing buttons (unicondylar resurfacing)
or polymer implant surfaces designed to restore congruity.

Technique:
Arthrotomy or arthroscopy-assisted placement with press-fit or cemented fixation.

B. Patellofemoral Resurfacing

Indicated in:

• Patellofemoral cartilage erosion

• Chronic maltracking leading to bone-on-bone grinding

• Failed corrective osteotomy with persistent pain

Resurfacing components restore smooth articulation and reduce mechanical abrasion.

C. Total Knee Replacement (TKR)

Still rare in veterinary medicine but used in research and specialized centers.

Implants include:

• Tibial and femoral metallic components

• Polyethylene interpositional spacer

Outcomes are improving, but complication rates remain higher than THR.

4. Shoulder Arthroplasty

The shoulder is less commonly replaced, but arthroplasty is indicated for:

• Glenohumeral osteoarthritis

• Chronic instability with articular wear

• Non-reconstructable humeral head defects

A. Glenoid Resurfacing

Metal-backed polyethylene glenoid component, cemented into position.

B. Humeral Head Replacement

Porous-coated humeral head anchored with a stem or uncemented implant.

Results can be excellent but available only at specialized centers.

5. Interpositional and Salvage Arthroplasty

In cases where joint replacement is not possible, interpositional arthroplasty serves as an alternative.

Indications:

• Young patients not ideal for total replacement

• Focal defects

• Chronic instability

Materials:

• Fascia lata autografts

• Synthetic materials (porous polyurethane)

• Meniscal allografts (experimental)

Arthrodesis remains the salvage option for joints unsuitable for arthroplasty.

6. Surgical Planning and Perioperative Considerations

Across all arthroplasty types, surgeons must:

• Perform precise imaging (radiographs, CT)

• Template implants preoperatively

• Use strict aseptic technique

• Avoid malalignment to prevent accelerated wear

• Implement perioperative antibiotics and multimodal analgesia

• Communicate realistic expectations to owners

7. Postoperative Management

Typical protocols include:

• 6–8 weeks of strict activity restriction

• Controlled leash walks

• Delayed strengthening exercises

• Hydrotherapy when incisions heal

• Long-term weight management

Radiographs at 6–10 weeks, 6 months, and annually assess implant integrity.

8. Prognosis

Outcomes vary by joint:

• CUE resurfacing: excellent for medial compartment disease

• TER: moderate success with higher complication rates

• Stifle resurfacing: promising but limited data

• Shoulder replacements: very good in appropriate candidates

Owner compliance is the strongest determinant of success.

Surgeon-Facing FAQ: Joint Replacement Arthroplasty (Non-Hip)

1. When should arthroplasty be considered instead of arthrodesis?

When preservation of joint motion is desirable and pathology is isolated to articular surfaces with intact soft-tissue support.

2. Which joint has the most predictable outcomes?

CUE (medial compartment elbow resurfacing) currently offers the most consistent results among non-hip arthroplasties.

3. Why is Total Elbow Replacement less common?

The elbow's complex biomechanics make alignment difficult, and complication rates remain high.

4. Are partial resurfacing implants load-sharing or load-bearing?

They are load-sharing, redistributing forces away from damaged cartilage.

5. What imaging modality is ideal for arthroplasty planning?

CT is ideal for elbow and stifle arthroplasty due to complex bone geometry.

6. Is cementless fixation preferred in non-hip arthroplasty?

Yes, when bone quality is sufficient; cemented fixation is reserved for osteopenic or irregular bone.

7. How soon can dogs begin rehabilitation?

PROM within days 2–3, strengthening around 4–6 weeks, hydrotherapy once soft tissues heal.