How Knee Replacement Surgery Works — From the Operating Table to Walking Again

Knee replacement is one of the most successful operations in modern surgery. Over 90 percent of patients report significantly reduced pain and improved mobility. Implants are designed to last fifteen to twenty-five years. And recovery, while it takes months for full function, is steadier and more predictable than most patients expect beforehand.

Understanding what actually happens during the procedure — and what the recovery stages look like — tends to make the whole prospect far less daunting.

Why the Knee Wears Out

The knee is a hinge joint with a slight rotational component. The ends of the femur (thigh bone) and tibia (shin bone) are covered with smooth cartilage that allows them to glide against each other with minimal friction. The menisci — two C-shaped cushions between the bones — add to this shock absorption.

When cartilage wears away — from osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, or other causes — bone meets bone. The result is pain, stiffness, swelling, and gradually worsening loss of mobility. Once the damage reaches a significant level, no amount of physiotherapy, weight management, or injection can restore the cartilage that is gone.

Knee replacement removes the damaged bone and cartilage surfaces and replaces them with metal and plastic components that recreate a smooth, functioning joint.

Total vs Partial Knee Replacement

Total knee replacement (TKR) replaces all three compartments of the knee — the medial (inner), lateral (outer), and patellofemoral (kneecap-to-thigh bone). The standard procedure for knee arthritis affecting the full joint.

Partial (unicompartmental) knee replacement (UKR) is an option when arthritis is genuinely confined to one compartment — most commonly the medial compartment. Only that section is replaced. The cruciate ligaments and healthy compartments are preserved. Recovery is faster and the knee feels more natural, because more of the original anatomy remains. The limitation: not all patients are candidates. The arthritis must be truly confined, the ligaments must be intact, and the deformity must not be severe.

The Surgery — What Happens

The patient is under general or spinal anaesthesia. A tourniquet is applied to the thigh to reduce bleeding during the operation.

The surgeon makes an incision over the front of the knee — typically ten to fifteen centimetres. The patella (kneecap) is moved to the side, exposing the joint.

1. Bone preparation: Using precision cutting guides, the surgeon removes the damaged bone and cartilage from the end of the femur and the top of the tibia. The cuts must be accurate — even a few degrees of error in alignment affects how the implant functions. This is where robotic assistance adds precision.

2. Trial components: Before the real implants are cemented or press-fitted, trial components are placed to check alignment, stability, and range of motion. The surgeon flexes and extends the knee, checks for equal tension in the ligaments on both sides, and confirms the mechanical axis — the line from hip to ankle — passes through the centre of the joint. Adjustments are made before the final implants go in.

3. Final implantation: The tibial baseplate and femoral component are fixed — either with bone cement or press-fit into the bone for biological ingrowth (cementless). A plastic insert clips into the tibial baseplate. A patellar button may be added to the back of the kneecap. The wound is closed in layers.

The operation takes ninety minutes to two hours.

Robotic Knee Replacement — What It Changes

Standard knee replacement uses mechanical jigs aligned by the surgeon's judgement to make the cuts. Results depend on the surgeon's experience and technique. Robotic assistance uses a CT-based three-dimensional model of the patient's specific anatomy — made before surgery — to plan the cuts precisely. During surgery, the robotic arm constrains the cutting instrument to stay within the pre-planned boundaries.

Implant positioning is accurate to within fractions of a millimetre. Studies show better limb alignment, fewer outliers, and — in longer follow-up — lower revision rates with robotic technique.

The MAKO Robotic-Arm Assisted Surgery system is the dominant platform for robotic knee replacement. Available at Artemis Hospital Gurugram and Fortis Memorial Research Institute Gurugram, both Prime Medical partners.

Recovery — What Each Stage Looks Like

1. Day of surgery: The patient wakes in recovery with a drip, catheter, and compression stockings on the legs. The operated leg is elevated. Ice packs reduce swelling. The physiotherapist visits within hours.

2. Day one: The patient stands at the bedside and takes first steps with a walking frame. The goal is getting the knee moving as soon as possible — prolonged immobility risks stiffness and blood clots.

3. Days two to three: Walking increases. Stairs are attempted under physiotherapy supervision. The catheter is removed. Pain is managed with a combination of anti-inflammatories, paracetamol, and nerve blocks — opioid use is minimised to avoid slowing recovery.

4. Discharge (day three to five): Home or accommodation with a walking frame or crutches. A formal physiotherapy programme begins. The exercises focus on restoring range of motion and strengthening the quadriceps.

5. Weeks two to four: Reducing dependence on the walking frame. Range of motion improving. Most patients can walk independently — without aids — by six to eight weeks.

6. Three to six months: Near-full function for most activities. Kneeling and deep squatting remain difficult for some patients depending on anatomy and implant design.

Orthopaedic Hospitals in Prime Medical's Network

Artemis Hospital, Gurugram (JCI, NABH) — Prime Medical partner. MAKO robotic knee replacement. Strong orthopaedic department. Good option for patients from East and West Africa.

Fortis Memorial Research Institute, Gurugram (JCI, NABH, NABL) — MAKO robotic system. Revision knee replacement for complex cases. Advanced post-operative physiotherapy.

Max Super Speciality Hospital, Saket, Delhi (JCI, NABH, NABL) — Robotic knee replacement. Strong orthopaedic team. Treats patients from Ethiopia, Uganda, Tanzania regularly.

Indraprastha Apollo Hospital, New Delhi (JCI, NABH) — Full orthopaedic programme including robotic replacement. Africa desk.

For patients from Addis Ababa, Hawassa, Mekelle, Kampala, Jinja, Dar es Salaam, or Banjul with knee arthritis: share your standing X-rays with Prime Medical Solutions. A specialist reviews within 48 hours.

To book a consultation, call the number on our website.