Understanding Knee Osteoarthritis
Knee osteoarthritis (OA) is the most common reason for knee replacement surgery. It is a degenerative joint disease in which the protective cartilage that cushions the ends of your bones gradually wears away. As cartilage deteriorates, bone begins rubbing against bone — causing pain, swelling, stiffness, and progressive loss of function.
In India, over 45 million people suffer from knee OA. It predominantly affects individuals above 50, though younger patients with post-traumatic arthritis or inflammatory joint disease may require surgery earlier. Total knee replacement (TKR) is now one of the most performed orthopaedic surgeries in the world, with excellent long-term outcomes.
Common Causes
- Primary osteoarthritis (age-related wear)
- Post-traumatic arthritis after fractures
- Rheumatoid arthritis
- Obesity — excess load on joint cartilage
- Meniscal tears leading to secondary OA
- Avascular necrosis (AVN) of the femoral condyle
Who Is at Risk?
- Age > 50 — risk rises sharply
- BMI > 30 — 4× higher OA risk
- Female gender — especially post-menopause
- Family history of joint disease
- Prior knee injury — ACL/meniscal tears
- Prolonged squatting occupations (Indian lifestyle)
5 Key Signals It's Time for Surgery
Not every arthritic knee needs replacement. The decision is based on a combination of clinical examination, imaging, and — most importantly — your functional impairment. Here are the five signals we look for:
Pain That Limits Daily Activities
If knee pain stops you from walking more than one block, climbing stairs, rising from a chair, or sleeping through the night — and this has persisted for 6+ months despite medication — that is a strong indicator. The key is functional limitation, not pain score alone.
Failed Conservative Treatment
Conservative options (detailed below) must be tried first. If 6–12 months of physiotherapy, weight loss, NSAIDs, and injections have provided inadequate relief, surgery becomes the appropriate next step.
Significant Deformity — Varus or Valgus
Bow-leg (varus) or knock-knee (valgus) deformity visible on clinical examination or X-ray indicates advanced joint destruction. Deformity beyond 15° is difficult to correct with anything short of joint replacement.
Severe X-ray Changes (Grade 3–4 OA)
Kellgren-Lawrence grade 3–4 on standing AP X-rays — meaning near-complete loss of joint space, subchondral sclerosis, large osteophytes, and bone-on-bone contact — correlates strongly with surgical candidacy when combined with symptoms.
Psychological Readiness and Medical Fitness
Surgery succeeds best when patients understand the procedure, have realistic expectations, and are medically optimised (controlled diabetes, BP, BMI). A patient who is medically fit and psychologically prepared does significantly better.
Conservative Options — Try These First
Surgery is never the first step. We always recommend exhausting non-surgical options before recommending knee replacement. Here's what should be tried:
Medications
- Paracetamol (first line)
- NSAIDs — Diclofenac, Etoricoxib (short-term)
- Duloxetine for chronic pain
- Topical diclofenac gel
- Glucosamine/chondroitin (limited evidence)
Physiotherapy
- Quadriceps strengthening (VMO focus)
- Low-impact aerobics — cycling, swimming
- Proprioception training
- TENS and ultrasound therapy
- Assistive devices — knee brace, walking stick
Injections
- Corticosteroid injection — acute flare relief
- Hyaluronic acid (viscosupplementation)
- PRP (platelet-rich plasma) — early OA
- Relief typically lasts 3–6 months
The Right Timing
One of the most common questions I hear in clinic: "Doctor, am I too young for a knee replacement?" or "Should I wait longer?"
The honest answer is: don't wait until you can't walk at all. The best surgical outcomes occur when patients are still relatively mobile and their muscles are not severely wasted. Waiting too long means:
- Severe quadriceps atrophy making rehabilitation harder
- Fixed deformity requiring more complex correction
- Bone loss that may require augmented implants
- Psychological suffering that affects recovery motivation
Types of Knee Replacement
Total Knee Replacement (TKR)
All three compartments (medial, lateral, patellofemoral) are resurfaced. Indicated for pan-compartmental OA with or without deformity. Most commonly performed — over 95% of cases.
Unicompartmental Knee Replacement (UKR)
Only the damaged compartment (usually medial) is resurfaced. More bone preserved, faster recovery, more natural feel. Suited for isolated medial OA in younger, less obese patients.
Patellofemoral Replacement
Resurfaces only the undersurface of the kneecap and the trochlear groove. Used for isolated patellofemoral OA causing anterior knee pain, especially in younger women.
What Happens in the Operation Theatre
Understanding the procedure reduces anxiety and helps patients prepare for recovery. Here is a step-by-step walkthrough of a standard total knee replacement:
Anaesthesia
Most TKRs in India are performed under spinal anaesthesia (SAB) — you are awake but numb from the waist down. This avoids the risks of general anaesthesia and speeds recovery. A nerve block (femoral/adductor canal) may be added for superior post-op pain control.
Skin Incision & Exposure
A straight midline incision (~15 cm) over the front of the knee. The quadriceps tendon is split medially (medial parapatellar approach) to expose the joint. The patella is everted to provide full visualisation.
Bone Resection
Precise cuts are made on the distal femur, proximal tibia, and patella using measured cutting guides and/or computer navigation. The goal is restoring the normal mechanical axis — a straight line from hip to ankle.
Trial Components
Trial implants are inserted and the knee is put through a full range of motion. Alignment, stability, and flexion gap are checked. Adjustments are made before cementing the final components.
Final Implant Fixation
The femoral component (cobalt-chromium), tibial component (titanium with polyethylene insert), and patellar button are cemented into position. The cement is pressurised into the bone for a strong bond.
Closure & Drain
The joint is washed thoroughly. A drain may be placed. The capsule and skin are closed in layers with absorbable sutures. A compressive dressing is applied. Total surgical time: approximately 90–120 minutes.
Recovery Timeline
Day 0–1 (In Hospital)
You will be sitting up and bearing weight with a walker within 4–6 hours of surgery. Ice packs, elevation, and nerve block keep pain manageable. Drain removed at 24 hours.
Day 2–4
Walking with walker, stair practice begins. Physiotherapy 2× daily. Most patients are discharged on Day 3–4 once they can walk independently and manage stairs safely.
Week 2–6
Transition from walker to cane. Wound check at 2 weeks, sutures removed. Range of motion exercises — target is 0–90° by week 4 and 0–120° by week 6.
Month 3
Most patients walk without any aid. Pain is largely resolved. Return to driving, light household activities, and desk work. Follow-up X-ray at 6 weeks and 3 months.
Month 6–12
Full recovery. Activities like climbing hills, social outings, and travel resume. The implant continues to "bed in" — many patients report ongoing improvement up to 1 year.
Expected Outcomes
Total knee replacement is one of the most successful operations in all of medicine. Evidence from large registry studies shows:
Success Rates
- 95% patient satisfaction at 1 year
- 90% implant survival at 15 years
- 85% implant survival at 20 years
- Pain reduced by >70% in most patients
Functional Gains
- Walk unlimited distances on flat ground
- Climb stairs independently
- Drive a car (automatic) from ~6 weeks
- Resume gentle sports (swimming, cycling)
- Vastly improved sleep quality
Common Questions
Is knee replacement painful?
Modern pain management — nerve blocks, multimodal analgesia, and ice therapy — means most patients are surprised by how little pain they experience. The first 48–72 hours are the most uncomfortable; after that, pain improves rapidly.
How long will the implant last?
Modern implants last 15–25 years in most patients. Younger, more active patients may need a revision surgery at some point, but this is straightforward in most cases.
Can I sit cross-legged after TKR?
Most standard TKR implants do not allow deep flexion beyond 120–130°. Sitting cross-legged or on the floor is generally not possible after TKR. A high-flexion implant may be considered for patients with this lifestyle requirement.
Is there an age limit for knee replacement?
There is no upper age limit. We have successfully operated on patients in their 80s and 90s. Medical fitness matters more than age. Well-controlled comorbidities with spinal anaesthesia make TKR safe even in elderly patients.
What happens if I delay surgery?
Progressive bone loss, increasing deformity, muscle weakness, and reduced mobility. Surgery becomes technically harder and recovery is longer when done on a severely neglected joint. Early intervention within the right window gives the best results.
Ready to Make a Decision?
Dr. Maninder Singh offers personalised consultations to assess whether you are ready for knee replacement, or whether conservative treatment still has more to offer. Bring your X-rays and come in for an honest evaluation.