2 Mai 2026
Author: Dr. Alexandru Grecu — Senior Orthopedic and Trauma Surgeon
Medically reviewed by Dr. Alexandru Florian Grecu, Senior Orthopedic Surgeon · Published: 2 mai 2026 · Updated: 2 mai 2026
This guide answers the questions my patients have asked me over the years. They are real, recurring, important questions. I have organized them into 5 sections — from the decision to operate through to life after surgery. If your question is not here, give me a call and we will add it.
There isn't a single definitive test. The decision is based on 4 factors: (1) pain severity—pain that doesn't respond to anti-inflammatories and affects sleep; (2) functional limitation—you can no longer walk more than 200–300 m, climb stairs, or sleep on the affected side; (3) radiological imaging—visible cartilage wear; (4) response to conservative treatment—physical therapy, injections, and NSAIDs have been tried for at least 6 months. If you meet 3–4 of these criteria, it's likely time.
There is no minimum age; there are clinical criteria. Under 50, we try the entire conservative arsenal. Between 50–60, the decision is made individually. Over 60, the indications become more relaxed. The youngest replacements I've performed were on 35–40 year-old patients with severe avascular necrosis; the oldest were over 85, when their general condition permitted.
It's never 'too late'—but over 85, I carefully assess cardiovascular status and life expectancy. For a healthy 88-year-old with severe pain who has given up walking, a replacement is a valid decision.
In early and moderate stages (Kellgren-Lawrence I-II): yes, in many cases. In advanced stages (III-IV), conservative treatment slows progression but doesn't stop it. At some point, the pain and functional loss will justify surgery.
Total: replaces all 3 joint compartments. It's indicated when wear is widespread. This accounts for 90% of my cases. Partial (unicompartmental): replaces only 1 compartment when the wear is localized there. Advantages: smaller incision, faster recovery, better mobility. Disadvantage: if the wear spreads, a total replacement will be needed later.
We usually operate on one knee at a time. The interval between the two surgeries is typically 6–12 months. Exceptionally, for patients in excellent general health, a 'bilateral' procedure—both knees on the same day—can be performed. This is rarer and carries additional risks.
See the dedicated article 'How to Choose Your Orthopedic Surgeon for Joint Replacement' on this site. In short: volume, communication, team, and transparency about alternatives and risks. A second opinion is a healthy practice.
Standard: blood tests (CBC, biochemistry, coagulation); ECG + cardiology consultation; chest X-ray; X-ray of the joint to be operated on (in two views); possibly an MRI; anesthesia consultation. For patients with comorbidities: additional tests depending on their profile.
Non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin in antiplatelet doses: stop 5–7 days before. Oral anticoagulants (Sintrom, Eliquis, Xarelto): stop according to protocol—it depends on the reason. Immunosuppressants: consult with a rheumatologist. Dietary supplements (ginkgo, ginseng, high-dose omega-3): stop 1 week before. Antidepressants, antihypertensives, anti-diabetics: continue as usual.
If you have severe obesity (BMI > 35–40), yes. Surgery on obese patients has: a higher risk of post-operative infection; a higher risk of thrombosis; the implant wears out prematurely under excessive weight; the surgical technique is more difficult. I recommend a gradual weight loss of 10–20% of your body weight before surgery.
I strongly recommend quitting smoking at least 6–8 weeks beforehand. Smokers have a 2–3× higher risk of post-operative infection; impaired wound healing; and a higher risk of pulmonary complications during anesthesia.
8–12 hours before surgery: nothing to eat. 2 hours before: nothing to drink. In the weeks leading up to the surgery: a normal, balanced diet; iron supplements if you are anemic; good hydration; recommended doses of vitamin D if you have a deficiency.
Before surgery, arrange for: a bed on the ground floor or in an accessible room; a toilet with a 'riser' (10–15 cm); a grab bar in the bathroom; a handle on the shower chair; a walker or crutches (you will get these from the hospital); a mobile phone within reach; a 2-week supply of food; a support person for the first 2 weeks; emergency phone numbers written down in a visible place.
Essentials: documents (ID, Romanian public insurance (CAS) card); test results + X-rays; list of medications; pajamas / comfortable clothes; non-slip slippers; personal hygiene items; phone + charger; something to read. Avoid: jewelry; large sums of money; robes with buttons or ties.
Standard knee replacement: 60–90 minutes. Standard hip replacement: 60–90 minutes. Complex cases (revision, large deformities, previous infection): 90–180 minutes. Knee arthroscopy: 30–90 minutes. Total time in the operating theater area: 2–4 hours on the day of surgery.
Not necessarily. Most replacement surgeries are performed under spinal anesthesia: an injection in your back that 'numbs' the lower part of your body; you are awake but feel nothing below the waist. Advantages: faster recovery, less post-operative pain, lower cardiovascular risk. General anesthesia is used when a patient has contraindications to spinal anesthesia or the surgery is very long.
Under spinal anesthesia: no. Under general anesthesia: no. If you experience any unpleasant sensation during spinal anesthesia, tell the anesthesiologist—the sedation can be adjusted.
There is a sterile drape (a kind of tent) that visually separates you from the surgical area. You will not see the operation.
For knee/hip replacements: 200–500 ml of blood is lost intra-operatively. For anemic patients or those on anti-thrombotic medication: intra-operative tranexamic acid (reduces bleeding by 30–50%); possibly auto-transfusion; very rarely: blood transfusion from a donor.
A minimum of 4–5 people: the lead surgeon; an assistant surgeon; an anesthesiologist; an anesthesia nurse/assistant; a scrub nurse (or 2); possibly a resident or intern in training (with your consent).
Standard knee replacement: 3–5 days. Standard hip replacement: 4–6 days. Arthroscopy: day surgery.
Knee replacement: normal walking at 6–8 weeks; 'almost complete' recovery at 3–6 months; maximum mobility at 6–12 months. Hip replacement: normal walking at 6–8 weeks; almost complete recovery at 3–6 months; maximum mobility at 6 months.
In the first 1–2 days: severe, but controlled with IV medication. Days 3–7: moderate, with oral medication. Weeks 1–4: mild to moderate pain. After 4–6 weeks: the pain progressively decreases. At 6 months: 80–90% of patients report 'virtually no pain'. Chronic residual pain (lasting over 6 months) occurs in 10–15% of patients, usually moderate and tolerable.
Pain relievers (paracetamol, ibuprofen, possibly tramadol in the first few days); an anticoagulant (usually subcutaneous or oral, for 4–6 weeks post-op); prophylaxis for gastric ulcers if you take NSAIDs; antibiotics only for the first 24–48 hours peri-operatively.
In the hospital: daily, starting from the second day post-op. After discharge, for the first 4–6 weeks: 3–5 sessions per week. Weeks 6–12: 2–3 sessions per week. Months 3–6: 1–2 sessions per week, plus exercises at home.
In the first 6–12 weeks: you NEED a physical therapist—for correct technique, precise manipulations, and progress monitoring. After 3 months: you can maintain with home exercises, with periodic evaluations. I DO NOT recommend 'physical therapy from a YouTube video' for the immediate post-operative period.
Right knee replacement: at 6–8 weeks. Left knee replacement with an automatic car: at 4–6 weeks. Hip replacement: at 6–8 weeks. Knee arthroscopy: at 1–4 weeks.
First 4–6 weeks: avoid flights, especially long ones (risk of thrombosis). After 6 weeks: short flights (under 4 hours) are OK. After 3 months: normal flights, no restrictions.
Modern knee replacement: 15–25 years for patients who follow recommendations. Modern hip replacement: 20–30 years for patients who follow recommendations. The technology is constantly improving.
In the first few months: possibly. At 6 months: 80% of patients 'no longer feel it'. At 1 year: most forget they have a replacement.
Allowed (after 3–6 months): walking, swimming (all strokes), cycling, yoga, Pilates, golf, hiking (with poles), dancing, recreational tennis, cross-country skiing. Not recommended or permanently forbidden: regular running, repetitive jumping, impact sports (soccer, rugby), high-speed downhill skiing, martial arts with impact, intense squash, intense badminton.
Knee replacement: after 4–6 weeks. Hip replacement (posterior approach): after 6–12 weeks. Hip replacement (anterior approach): after 4 weeks.
After a knee replacement: after 4–6 weeks, in positions that do not place maximum stress on the knee. After a hip replacement (posterior approach): after 6 weeks, avoiding deep hip flexion for the first 3 months; after 3 months, no restrictions. After a hip replacement (anterior approach): fewer restrictions, after 4 weeks.
Yes, most likely. You will receive a medical card from the hospital explaining the implant. Present it at security screening. Airport staff are used to this situation.
Current protocol: prophylactic antibiotics only for major dental procedures (extractions, endodontics); within the first 2 years post-implantation; for patients with risk factors (diabetes, immunosuppression). Discuss your specific case with your dentist and me.
The list above covers 90% of the questions I receive. The remaining 10% are specific to each patient. The best answers come at the consultation, when I can see your X-rays and we can discuss your case in concrete terms.
Write to me or call — we will add your question to the list after I have answered it at the consultation. You may help other patients who have the same uncertainty.
Appointments: +40 251 960 (MedLife) or +40 787 210 391
Consultations: with Romanian public insurance (CAS) or private (360 RON). Monday–Friday, 08:00–18:00.
Felson DT et al. — Weight loss reduces the risk of symptomatic knee osteoarthritis in women. Ann Intern Med. 1992;116(7):535-9.
For the rule 'losing 5 kg can reduce knee pain by 20-30%'.
Messier SP et al. — Effects of intensive diet and exercise on knee joint loads in adults with knee osteoarthritis. JAMA. 2013;310(11):1226-1235.
For the rule '1 kg of body weight = approximately 4 kg of pressure per knee with each step'.
Bourne RB et al. — Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clin Orthop Relat Res. 2010;468(1):57-63.
For the >90% satisfaction rate after knee replacement.
Swedish Hip Arthroplasty Register — Annual Report 2022.
For the long-term success rate of hip replacement.
Allen KD, Golightly YM — Epidemiology of osteoarthritis: state of the evidence. Curr Opin Rheumatol. 2015;27(3):276-83.
For the prevalence of knee osteoarthritis and risk factors (3-4 times more common in women).