Courtesy: Dr T Vail, Ashok Shyam TV, Ortho

Stiff and Painful Knee After Total Knee Replacement

1. Basic Concept

Total knee replacement works well in the vast majority of patients, but the small proportion with persistent problems can require substantial clinical attention.

The typical scenario is a knee that:

• Looks satisfactory radiographically
• Does not feel right to the patient
• Feels stiff or swollen
• Has inadequate flexion
• May have crepitation
• May feel unstable
• May have pain

Possible causes include:

• Scar tissue
• Arthrofibrosis
• Patellar clunk
• Synovial or scar tissue growing into the intercondylar area
• Implant-related problems
• Infection

Pain and stiffness are important contributors to patient dissatisfaction after TKA.

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2. Functional Range of Motion

Approximate knee flexion requirements mentioned in the lecture:

Activity	Flexion required
Normal ambulation	40–55°
Climbing stairs	~85°
Getting out of a low chair	More than 85°
Kneeling	Greater flexion required

Therefore, the goal is not simply to obtain a particular numerical range but to achieve functional motion appropriate for the patient’s activities.

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3. Stiffness Is a Final Common Pathway

A very important concept is:

Stiffness is a final common pathway rather than a diagnosis by itself.

Multiple different problems can eventually present as the same clinical picture of pain and stiffness.

Possible causes

• Chronic pain syndrome
• Infection
• Kinematic problems
• Component oversizing
• Poorly administered rehabilitation
• Biological factors related to fibrosis or collagen response
• Loosening
• Polyethylene wear
• Wear-related synovitis
• Instability
• Malalignment

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4. Early vs Late Stiffness

Early stiffness

Potential causes include:

• Infection
• Technical factors
• Patient-related factors
• Inadequate rehabilitation

Late stiffness

Consider:

• Implant loosening
• Polyethylene wear
• Wear-related synovitis
• Instability
• Infection
• Other implant-related abnormalities

Important principle

Do not treat stiffness as simply arthrofibrosis until other causes have been excluded.

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5. Clinical Scenarios

Scenario 1: Loose Cementless Implant

A patient develops early pain.

• Infection workup is negative.
• The knee does not function well.
• The cementless implant has failed to achieve bone ingrowth.
• The implant is loose.

Lesson

Early pain and stiffness can be related to implant fixation failure, even when infection is excluded.

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Scenario 2: Infection

Patient develops:

• Pain
• Chronic effusion
• Stiffness

The implants appear well fixed radiographically.

Investigation demonstrates infection.

Lesson

A well-fixed implant does not exclude infection.

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Scenario 3: Polyethylene Wear

A patient has:

• A previously well-functioning knee
• Late instability
• Progressive loss of flexion

The underlying problem is polyethylene wear.

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Scenario 4: Wear-Related Synovitis

A patient develops:

• Late pain
• Effusion
• Diminishing range of motion
• Well-fixed implants

The cause is wear-related synovitis.

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6. Patient Factors

Some factors may predispose to postoperative stiffness or influence expectations.

Patient habitus

• Size of the patient
• Size of the leg
• Soft-tissue envelope

These may influence achievable range of motion and patient expectations.

Previous trauma

Post-traumatic knees may have:

• Skin scarring
• Adhesion of skin to deeper tissues
• Increased soft-tissue fibrosis

These factors may predict poorer postoperative motion.

Important principle

Preoperative expectations regarding postoperative range of motion should be discussed with the patient.

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7. Posterior Compartment

The posterior compartment is particularly important for achieving knee flexion.

Attention should be given to:

• Posterior osteophytes
• Posterior soft tissues
• Adequate posterior clearance

Failure to address posterior pathology may contribute to limited flexion.

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8. Early Management of Limited Motion

The important principle is progressive improvement rather than achieving a specific numerical target immediately.

The surgeon should look for:

Progressive improvement in range of motion.

If the patient is not demonstrating progressive improvement, early intervention should be considered.

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9. Manipulation Under Anaesthesia

The speaker describes performing manipulation when the patient is not showing adequate progression, generally:

Within the first 6–8 weeks

The emphasis is on early recognition and intervention rather than waiting for severe established stiffness.

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10. Rehabilitation

Early rehabilitation is important.

The lecture emphasizes:

• Early weight bearing
• Appropriate rehabilitation
• Monitoring the progression of range of motion

CPM

Routine continuous passive motion is not used by the speaker.

The stated rationale is that routine CPM may reduce length of stay but does not necessarily improve the final outcome.

However, CPM may be considered in:

• Unmotivated patients
• Patients who are slow to regain motion
• Particularly in revision settings

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11. Previous Stiffness in the Opposite Knee

A history of stiffness in the contralateral knee is important.

Patients with previous stiffness may have:

• Greater risk of postoperative stiffness
• Greater likelihood of requiring manipulation
• Less predictable restoration of motion

Clinical implication

If the patient has previously demonstrated stiffness in the opposite knee, be particularly aggressive with early rehabilitation and monitoring.

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12. Technical Causes of Stiffness

Several technical factors can contribute to pain and stiffness.

Component sizing

Avoid:

• Oversized femoral component
• Oversized tibial component
• Component overhang

These can produce:

• Soft-tissue tension
• Pain
• Stiffness

Patellofemoral joint

Avoid overstuffing the patellofemoral joint.

Mobile-bearing implants

With a highly conforming mobile-bearing implant:

• Ensure cement or bone does not interfere with the mobile bearing.
• The bearing must remain free to move appropriately.

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13. PCL and Kinematics

In a cruciate-retaining knee, an insufficient PCL can produce abnormal kinematics.

The lecture describes:

• Paradoxical motion
• Forward movement of the contact point
• Posterior impingement
• A sensation of stiffness

Therefore, PCL function and appropriate kinematics are important when evaluating a stiff knee.

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14. Late Management of Stiffness

Established late stiffness requires identification of the underlying cause.

Potential treatments include:

• Revision surgery if there is an implant-related problem
• Open excision of scar tissue
• Complete capsulectomy when appropriate

Arthroscopy

The lecture emphasizes that arthroscopy is rarely helpful in established stiffness.

An exception may be selected cases involving:

• Poorly balanced PCL
• Cruciate-retaining knee

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15. Complete Capsulectomy

When reoperating for significant stiffness, the lecture describes a complete capsulectomy involving:

• Medial gutter
• Lateral gutter
• Patellofemoral joint

The goal is to remove established scar tissue and restore soft-tissue mobility.

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16. Revision for Stiffness

Revision may be considered when there is an identifiable correctable abnormality, such as:

• Loosening
• Malalignment
• Oversizing
• Other component-related abnormalities

Revision may improve range of motion, but restoration to normal motion is not guaranteed.

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17. Revision to Posterior-Stabilized Knee

The lecture notes that revision to a posterior-stabilized knee can improve range of motion in selected cases.

However:

• Improvement may remain incomplete.
• Many patients may still require manipulation.
• The final outcome depends substantially on the underlying cause.

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18. Expected Results After Revision

In the series discussed:

• Preoperative range of motion was approximately 42°
• Postoperative range of motion improved to approximately 85°

This represents a substantial functional improvement, although it is not a normal range of motion.

Both:

• Flexion
• Extension

could improve.

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19. Prognostic Factors

The lecture suggests that outcomes were somewhat better when there was a radiographic abnormality that could be corrected.

Interestingly, whether the PCL was competent or incompetent at the time of evaluation did not appear to determine the outcome in that series.

The key favorable factor was the presence of a correctable structural abnormality.

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20. Overall Management Approach

Patient with stiff and painful TKA

First: Identify the cause

Evaluate for:

• Infection
• Loosening
• Malalignment
• Oversizing
• Polyethylene wear
• Wear-related synovitis
• Instability
• Kinematic problems
• Arthrofibrosis

If early postoperative stiffness

Focus on:

• Progressive rehabilitation
• Early weight bearing
• Close monitoring of motion

If there is no progressive improvement, consider manipulation within approximately 6–8 weeks.

If established late stiffness

Consider:

• Open scar excision
• Complete capsulectomy
• Correction of component abnormalities
• Revision TKA when indicated

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High-Yield Exam Points

• • Stiffness is a final common pathway, not a diagnosis.
  • Always investigate the cause before treating presumed arthrofibrosis.
  • Important causes include infection, loosening, malalignment, oversizing, polyethylene wear, synovitis, instability and kinematic problems.
  • Functional flexion is approximately 40–55° for walking and about 85° for stair climbing.
  • Look for progressive improvement in the early postoperative period.
  • If motion is not progressively improving, manipulation may be considered within approximately 6–8 weeks.
  • Routine CPM is not recommended by the speaker, but may have a role in selected unmotivated or slow-to-progress patients.
  • Previous stiffness in the opposite knee is a warning sign.
  • Avoid femoral/tibial component oversizing and patellofemoral overstuffing.
  • The posterior compartment is important for flexion.
  • Late stiffness may require open scar excision and complete capsulectomy.
  • Arthroscopy is generally rarely useful for established stiffness.
  • Revision is more likely to help when there is a correctable radiographic abnormality.
  • Revision can improve motion substantially, but normal motion is not guaranteed.