What to Watch Before (and After) Joint Replacement to Improve Outcomes

Same surgeon. Same technique. Same implant.

So why is one patient back to walking the golf course by week 8 while another is still struggling with stairs five months later?

It’s not just what happens in the operating room. It’s what the patient brings into it.

Growing evidence shows that a patient’s physical readiness, mental state, support system, and even eating habits play critical roles in shaping recovery. In fact, some of these factors are just as predictive of outcomes as the surgery itself.

At Engivio, we’ve reviewed over 20 years of clinical studies and registry data to surface the most influential, and commonly overlooked predictors of recovery after hip or knee replacement.

Let’s break them down.

‍

Physical Readiness: Baseline Matters More Than You Think

Patients who are stronger, more mobile, and more active before surgery consistently recover faster and achieve better function. In a 2025 cohort study of over 6,100 hip and knee replacement in the U.S., preoperative functional status is one of the strongest predictors of their recovery and physical function one year after surgery. Notably, patients with better walking ability and functional scores before surgery tended to have better 12-month postoperative outcomes, independent of the surgical details (Nikkhah et al., 2025)

Obesity also plays a role. A meta-analysis found that higher BMI is associated with lower functional scores one year after TKA. Though improvement is still possible, the absolute gains tend to be smaller (Olsen et al., 2022).

Takeaway: Pre-op function predicts post-op outcomes.

Patients who start stronger, recover stronger. A short mobility screen or brief health survey before surgery can flag those who may benefit from targeted prehab, guided exercise, or weight support.

Even just 2–4 weeks of structured conditioning can improve lower limb strength, boost confidence, and make getting back on their feet faster and easier. 

The earlier we spot who might struggle, the sooner we can intervene

‍

Mental Health: The Hidden Driver of Outcomes

Anxiety, low mood, and catastrophic thinking aren’t just emotional states, they’re clinical risk factors. Analysis of over 5,000 TKA patients found that those with low preoperative mental health scores (VR-12 MCS < 40) showed less functional improvement and higher pain at one year. Those with strong mental health (MCS > 60) had better outcomes and were more likely to be discharged directly home (Rogers et al., 2022).

Low self-efficacy—patients’ belief in their ability to manage recovery—has a measurable impact on outcomes too. Even after accounting for age, comorbidities, and mood, patients with low pre-op confidence were more likely to experience delayed functional gains, higher pain, and increased reliance on post-op clinical support, including unnecessary visits for reassurance (Wylde et al., 2012). 

Takeaway:

Mindset impacts recovery.

Anxiety, low confidence, and negative beliefs can delay healing and reduce adherence—even when the surgical procedure goes well. Early screening for emotional readiness and pain coping helps identify who may benefit from more structured support.

What we measure, we can shape - and that applies to psychological readiness too.

‍

Support System: Powerful and Underestimated

Patients without at-home support face a tougher road to recovery — and the data backs it.

A study by Halawi et al. (2015, J Arthroplasty) found that TKA patients without caregiver support at home were significantly more likely to experience prolonged hospital stays and delayed recovery milestones. The authors noted that caregiver presence boosts patient confidence and enables earlier mobility and discharge.

That pattern holds across studies: patients with limited social support — such as living alone or lacking family assistance — tend to report lower satisfaction and slower recovery after joint replacement.

Similarly, Mehta et al. (2021) reported that patients without caregiver help at home had nearly 2× higher odds of 30-day readmission and were more likely to miss rehab exercises — a major contributor to poor outcomes.

Takeaway:

Having a reliable support person isn’t just nice to have.

When patients lack support, the right response isn’t to hope for the best. It’s to plan differently. Whether that’s home health services, rehab placement, or closer post-op follow-up.

‍

Nutrition: It’s Not Just About Weight

Nutrition often gets reduced to one number: BMI. But malnutrition isn’t just about weight and it’s not solved by having a “normal” or “high” BMI.

In joint replacement, up to 50% of patients show signs of undernutrition, regardless of body size. Malnutrition can exist in patients who are overweight or obese—especially if they have low protein intake, micronutrient deficiencies, or recent unintentional weight loss. One overlooked marker: low serum albumin, which has been strongly associated with slower wound healing, higher infection risk, and longer hospital stays.

In one study, joint replacement patients who received structured nutrition support (protein, vitamin D, iron) had fewer complications and faster functional gains—even when their BMI didn’t raise concern (Schroer et al., 2019).

Takeaway:

Nutrition is a recovery driver, regardless of body size.

Patients can look “well-nourished” and still be at risk. Simple screening questions (“Have you lost weight unintentionally?” “What’s your protein intake like?”) can flag hidden deficits early. Two to 4 weeks of targeted support - from protein shakes to dietitian-guided plans, can strengthen recovery and reduce complications.

Don’t let weight distract from what really fuels healing.

‍

Medical Risk Factors: Not Just for Anesthesia

Many joint replacement patients carry a heavy comorbidity load - hypertension, diabetes, COPD, chronic pain, anxiety disorders. A 2025 analysis found that patients with ≥5 chronic conditions scored 10 points lower on WOMAC at 12 months post-op compared to those with fewer comorbidities (Zhang et al., 2025).

Specific conditions, like diabetes and chronic back pain, are especially predictive of slower functional gains and higher complication risk.

Takeaway:

View comorbidities not just as pre-op clearance hurdles. 

Risk-stratified care planning like extra PT, closer follow-ups, tailored education - can change the outcome.

‍

Other “Soft” Factors Affecting Recovery

Even beyond the major categories above, a few intangible factors can make a difference in recovery – the kind of things doctors may not immediately see on a chart, but are very real in practice:

• Expectations: Patients’ expectations going into surgery can dramatically shape their satisfaction afterwards. In a study of over 1,700 knee replacements, unmet expectations were the number one driver of dissatisfaction at 1 year post-op – patients whose personal goals weren’t met were 10.7 times more likely to report being unhappy with their result . Conversely, those who felt their expectations were met were far more likely to be satisfied with their new joint. This means a patient who expects to run marathons after a knee replacement might feel let down even if their outcome is objectively good, whereas a patient whose goal was simply to walk without pain will be thrilled when that is achieved. Managing expectations (through education and honest dialogue) is key to ensuring the patient’s definition of success aligns with reality .
• Confidence and Motivation: These traits are hard to quantify, but any physical therapist will tell you they see a spectrum. Patients who believe in their own ability to recover – and who are motivated to actively participate (doing their home exercises, pushing through the rehab discomfort) – tend to make faster gains. On the other hand, patients who are fearful of movement or very passive can fall behind. There is research suggesting that self-efficacy(one’s confidence in doing activities) correlates with better functional improvement in rehab. Simply put, a positive “I can do this” attitude, coupled with strong motivation to reach personal goals (like getting back to golf or playing with grandkids), can propel recovery forward. Clinicians can foster this by celebrating small milestones and reinforcing progress, which builds the patient’s confidence to tackle the next challenge.
• Social and Environmental Factors: Beyond family support, things like the patient’s economic situation, home environment, and even health literacy come into play. For example, a patient who cannot afford time off work or doesn’t have a safe space to exercise will face extra hurdles in recovery. Similarly, someone who doesn’t fully understand their rehab instructions (due to language or education barriers) might unknowingly under-rehab or make mistakes. These factors are “soft” in that they vary widely, but being attuned to them – and connecting patients to resources (like arranging a home nurse visit for someone with limited mobility at home, or providing translated rehab instructions) – can make the rehabilitation period smoother.

‍

So What? Turning Insights into Action

These predictors aren’t just interesting facts – they’re actionable. They give surgeons and care teams a kind of “roadmap” to personalize care. Instead of guessing who might sail through recovery versus who might struggle, we can use these factors to stratify risk in advance. For example, if you know a patient has very low baseline mobility, high anxiety, and lives alone, you can proactively set up extra support: maybe prehab exercises, a care coach phone call, and a longer inpatient rehab stay. Conversely, a fit, optimistic patient with a great support network might speed through a standard pathway. The goal is to tailor the recovery plan to the whole person, not just the new joint.

At Engivio, we’ve integrated many of these predictors into our Recovery Snapshot – a real-time scoring tool that flags recovery risks before problems show up. By inputting a patient’s data on physical readiness, mental health, support, nutrition, and medical history, we generate a “heads up” report for the care team. For instance, if the snapshot highlights high catastrophizing or poor nutrition, targeted interventions can be offered right away. Predicting outcomes shouldn’t be a retrospective exercise – and a successful recovery shouldn’t be a black box. By watching these key factors before and after joint replacement, we can improve outcomes where it matters most: in the patient’s daily life after surgery.

‍

Sources: 

Lungu, E., Maftoon, S., Vendittoli, P., & Desmeules, F. (2016). A systematic review of preoperative determinants of patient-reported pain and physical function up to 2 years following primary unilateral total hip arthroplasty. Orthopaedics & Traumatology Surgery & Research, 102(3), 397–403. https://doi.org/10.1016/j.otsr.2015.12.025

Nikkhah, J., Schöner, L., Marques, C. J., Pros, C. M., & Busse, R. (2025). Treatment decisions and surgery variables are predictors of better physical function after total hip and knee arthroplasty: a retrospective cohort study. Arthroplasty, 7(1). https://doi.org/10.1186/s42836-025-00313-2

Olsen, U., Lindberg, M. F., Rose, C., Denison, E., Gay, C., Aamodt, A., Brox, J. I., Skare, Ø., Furnes, O., Lee, K., & Lerdal, A. (2022). Factors correlated with physical function 1 year after total knee arthroplasty in patients with knee osteoarthritis. JAMA Network Open, 5(7), e2219636. https://doi.org/10.1001/jamanetworkopen.2022.19636

Rogers, N. B., Grits, D., Emara, A. K., Higuera, C. A., Molloy, R. M., Klika, A. K., & Piuzzi, N. S. (2022). Preoperative Veterans Rand-12 Mental Composite Score of < 40 Leads to Increased Healthcare Utilization and Diminished Improvement After Primary Knee Arthroplasty. The Journal of Arthroplasty, 37(11), 2178–2185. https://doi.org/10.1016/j.arth.2022.05.033

Halawi, M. J., Vovos, T. J., Green, C. L., Wellman, S. S., Attarian, D. E., & Bolognesi, M. P. (2014). Preoperative predictors of extended hospital length of stay following total knee arthroplasty. The Journal of Arthroplasty, 30(3), 361–364. https://doi.org/10.1016/j.arth.2014.10.025