Why we ask each question · reviewed August 2026

See how we reach your result.

You should not have to trust a mysterious score. This page shows what we consider, why it matters, where the research is strong, and where the honest answer is still uncertain.

01Use only what is known today

Your answer is based on information available before surgery. We do not use what happened afterward to make an earlier prediction look better.

02Treat hips and knees differently

Hip and knee replacement have different recoveries, expectations, and likely results, so they should not share one formula.

03Say when we do not know

Missing information makes the answer less certain. We do not guess or quietly count a missing answer against you.

04Separate fit from preparation

Whether replacement may help is different from what can be improved before surgery. You deserve to see both separately.

What each answer adds

Why these questions matter to you

The research-strength label shows how firmly each finding should influence your result. No answer is used by itself to deny treatment.

What we look atWhat you tell usWhy it mattersResearch strength

How much the joint limits youDaily pain and activity questions

Shows how much your hip or knee is affecting ordinary life today.

Well established ↗What you need from surgeryYour most important goals

Unrealistic must-have goals—especially for knee motion, kneeling, and sports—can lead to disappointment.

Strong research ↗Pain elsewhereBack pain and other painful areas

Surgery may help less when much of your limitation comes from somewhere besides the joint being replaced.

Strong research ↗Whether hip or back is the main sourcePain location, standing, car entry, shoes and socks, and symptoms down the leg

Groin pain and pain with hip-demanding movements can favor the hip; pain below the knee or tingling and numbness can favor the spine or nerves. An examination is still needed.

Direct comparison study ↗What the X-rays showImages, examination, and diagnosis

The result is more useful when the damage seen on X-rays matches the symptoms you feel.

Moderate research ↗Medication and health preparationRegular opioid medication use and medical conditions

These answers identify issues to review before surgery; they should never be used by themselves to deny care.

Strong research ↗A surgeon’s opinionA goal-by-goal estimate

A formal opinion can add examination findings and a surgeon’s estimate of which goals are realistic for you.

Moderate research ↗The outcome that mattersGlad you chose surgery and would choose it again

Research supports asking whether patients feel surgery was the right choice—not only whether an X-ray looks better.

Expert consensus ↗

How the Fit Score is built

Potential benefit stands on its own.

The Joint Replacement Fit Score is built mostly from your standardized hip or knee score—a published, validated measure—then adds imaging, the likely pain source, quality of life, pain pattern, and treatment history. It describes how closely your story fits the usual reasons people benefit from replacement. If an X-ray score is missing, it is removed from the calculation rather than counted as zero, and a grade you only remember being told counts for less than one read from the report.

The number is an average, and an average lets a strong part cover for a weak one. So the result page does not lead with a band the evidence cannot bear. If your pain pattern points to another source, it leads with confirming the source. If a radiologist or your surgeon read the X-ray as minimal arthritis, it leads with that. If a part is unanswered, or the X-ray grade is only what you remember being told, the result is stated as provisional and names what would settle it. Beneath the score, four checks—symptoms and function, imaging evidence, pain source, and treatment response—are shown as states in words rather than as points, because none of them can make up for another. None of them denies care; each says what is established and what is not.

Joint health34%

X-ray severity18%

Joint-problem match18%

Quality-of-life impact16%

Pain pattern8%

Treatment history6%

Medical optimization, expectations, physical preparation, and home and social support receive their own scores and improvement suggestions. They do not lower the Fit Score. These starting weights and goals must be tested against TJS patient outcomes before they can be described as validated thresholds or a probability of benefit.

Why we avoid an overconfident calculator

A score that works in one hospital may fail somewhere else.

One published ten-question knee calculator looked promising at first, but later testing missed many patients who were unhappy after surgery. Your result should show uncertainty, be tested with new groups of patients, and never present a probability as more certain than the research allows.

See the study that changed our approach ↗

Read the research yourself

Sources behind the questions

How we keep the answer honest over time

Your result should become more trustworthy—not more mysterious.

Use proven questions

Start with established questions about pain and daily life, and explain why each answer matters

Learn from patients

Check who is glad they chose surgery at 3, 12, and 24 months

Test in other places

Make sure the hip and knee results work for patients outside JointVoyage

Show what we find

Publish how accurate and fair the result is—and how it improves over time

Keep reading

Wondering whether joint replacement fits your situation? Take the free TJV Fit Score — a cited, methodology-first assessment.