Comorbidity-Related Risks

Part of The Joint Replacement Guide — Phase 3: Understanding the Risks · Article 16 of 42 · Hip & Knee

Key Points

  • Existing health conditions influence your individual surgical risk and how your care is planned.
  • Having a comorbidity is not usually, on its own, a reason to avoid surgery — but it does need careful, individualised management.
  • Diabetes, obesity, cardiac disease, and immunosuppression are among the most relevant conditions to discuss with your team.
  • A multidisciplinary approach, sometimes involving specialists outside orthopaedics, is used for higher-risk patients.

Diabetes

Diabetes, particularly if poorly controlled, increases the risk of infection and slower wound healing after joint replacement. Well-controlled diabetes is not a barrier to surgery, and the focus is on optimising blood sugar control beforehand, as covered in the earlier article on pre-operative optimisation.

Obesity

Higher body weight increases technical difficulty and the risk of wound complications, as also covered in the optimisation article. This is addressed as a modifiable factor to work on together with your team wherever possible, rather than treated as an automatic barrier to referral or surgery.

Cardiac and Respiratory Disease

Existing heart or lung conditions increase anaesthetic risk, and are carefully assessed as part of pre-operative work-up. Depending on the severity of your condition, this may involve input from a cardiologist or respiratory specialist before a final decision is made about proceeding, and about the safest anaesthetic approach for you. The goal of this assessment is to weigh the benefits of surgery against your individual risk profile, in an honest, shared conversation — not to find a reason to decline treatment.

Immunosuppression

If you take medication that suppresses your immune system — for example, for rheumatoid arthritis or another inflammatory condition, or following an organ transplant — your infection risk after surgery is somewhat higher, and this needs to be planned carefully alongside the specialist team managing that underlying condition. In some cases, the timing of certain medication doses is adjusted around the time of surgery; this is always individualised and should be planned jointly between your surgical team and the specialist prescribing your medication, rather than something to change yourself without guidance.

Kidney Disease and Other Conditions

Kidney disease affects how your body handles fluids and certain medications around the time of surgery, and is factored into anaesthetic and post-operative planning. Other significant medical conditions are similarly assessed on an individual basis — the general principle across all of these is that your team wants a full and honest picture of your health in order to plan the safest possible care for you specifically, not a generic pathway.

How This Is All Brought Together

For patients with more complex health needs, many units run dedicated high-risk or complex pre-assessment clinics, often anaesthetic-led, that bring together the relevant specialists to plan your care as a team. This ties back to the shared decision-making conversation covered earlier in this guide — the aim is always an honest, individualised discussion of benefits and risks, not a blanket rule based on any single condition.

In More Depth

Anaesthetists commonly use standardised risk scoring systems, such as the ASA (American Society of Anesthesiologists) physical status classification, to help communicate and track surgical risk in a consistent way across a patient’s care team. These scores are a useful shorthand for clinicians but are only one part of a much fuller individual assessment, and shouldn’t be interpreted by patients as a simple pass/fail grade — many people with a higher ASA grade, reflecting more significant comorbidity, still go on to have safe, successful joint replacement surgery with appropriate planning.

This article is general information and does not replace individual clinical advice. Please discuss your specific health conditions and medications with your surgical and anaesthetic team.

Sources

  • Centre for Perioperative Care (CPOC) — guidelines for perioperative care in patients with comorbidities
  • Royal College of Anaesthetists — pre-operative assessment guidance
  • NICE guideline NG157 — Joint replacement (primary): hip, knee and shoulder (2020)

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