Partial Knee Replacement vs High Tibial Osteotomy

The choice between partial knee replacement and high tibial osteotomy arises when knee arthritis is confined to one compartment; both operations can delay or avoid a total knee replacement. A high tibial osteotomy realigns the leg so that body weight shifts off the worn side; a partial knee replacement resurfaces only the damaged compartment. Before either, early osteoarthritis is treated with weight control, exercise, offloader braces, medicines and joint injections.

Dr. Ishwar Bohra, Senior Director - Joint Replacement Programme, BLK-Max Super Speciality Hospital, New Delhi, India, set out this sequence in his Jivo Masterclass on degenerative joint disease for international doctors. His emphasis was on timing. The patient whose arthritis is caught while it still involves one side of the knee can be offered a small operation and a fast return to normal life; once arthritis has spread across the whole joint, total replacement is the remaining option. The diagnosis, risk factors and X-ray staging that decide which rung of the ladder a patient is on are covered in the complete guide to degenerative joint disease.

Before surgery: weight, exercise and support for the knee

Early knee osteoarthritis is managed first with weight control, exercise and support for the joint. Some risk factors for osteoarthritis are fixed, such as age and sex; the others can be changed, and Dr. Bohra grouped those into these three. These are measures patients can largely carry out themselves, and he presented them as a way both to prevent the disease and to stop its progression.

Weight comes first. Dr. Bohra described balancing body weight as the most important single step. He recommends a referral to a nutritionist, who can design a diet that suits the patient and a realistic plan to reduce weight.

Exercise is learned, then practised. The physiotherapy department teaches the right exercises; the patient then has to keep doing them. The exercises he recommends for any joint are:

• Quadriceps strengthening, for the large muscle at the front of the thigh that stabilises and protects the knee.
• Range-of-movement (ROM) exercises, which keep the joint supple.
• Swimming, which builds strength without loading the joint.
• Cycling, which moves the knee and hip through a wide arc against controlled resistance.

These, in his words, help prevent hip and knee arthritis. Major osteoarthritis guidelines agree: structured exercise and, where needed, weight loss are core first-line treatments for knee and hip osteoarthritis, recommended for every patient.

Walking aids and shoe modification

A cane, walker or adjusted footwear takes load off a painful joint. For patients with more advanced arthritis, Dr. Bohra advises a cane or walker for a couple of days. The aim is short-term: to rest the joint so that it settles back to its previous, less inflamed state.

Shoe modification is the second support measure. Adjusted footwear changes the balance of weight transfer through the knee and ankle, which can relieve a joint whose load is falling unevenly.

Offloader braces for knee osteoarthritis: bow legs and knock knees

An offloader brace shifts load away from the worn side of an unevenly worn knee. Osteoarthritis rarely wears a knee evenly. The knee may bend inwards or outwards: a bow-legged (varus) knee overloads the inner compartment, and a knock-kneed (valgus) knee overloads the outer one. Dr. Bohra noted that both patterns occur in arthritis.

Offloader braces, also called unloader braces, are designed for exactly this problem. A brace of this kind applies a gentle corrective force across the knee, shifting load away from the worn compartment towards the healthier one. Many varieties are available, and Dr. Bohra recommends them for the initial management of osteoarthritis. Together with lifestyle change, they relieve load and pain, although no brace has been shown to halt the progression of arthritis.

Medicines for early osteoarthritis

The medicines used in early osteoarthritis fall into two groups, nutraceuticals and analgesics. Most doctors who see joint pain already prescribe from this long list, and Dr. Bohra divided it as follows.

Nutraceuticals

The first group are nutraceuticals, supplements taken to support cartilage:

• Glucosamine
• Chondroitin
• Methylsulfonylmethane (MSM)
• Collagen preparations, including undenatured collagen

He noted that new products of this kind keep coming onto the market, and that they are used to enhance the strength of the cartilage. The evidence for them is mixed: major guidelines, including those of the Osteoarthritis Research Society International, the American College of Rheumatology and NICE, do not recommend glucosamine or chondroitin as routine treatment for knee osteoarthritis.

Analgesics

The second group are painkillers:

• Paracetamol (acetaminophen).
• COX inhibitors, the anti-inflammatory drugs that block cyclo-oxygenase enzymes, including the selective COX-2 inhibitors.
• Opioids.

Anti-inflammatory drugs carry gastrointestinal, kidney and cardiovascular risks with long-term use, and opioids carry a risk of dependence, so guidelines favour the lowest effective dose for the shortest period.

Knee injections for early osteoarthritis

Joint injections belong to the early stages of arthritis. The next step is the intra-articular injection, given directly into the joint. Dr. Bohra listed the options in current use:

• Hyaluronic acid, a lubricating gel that mimics a component of normal joint fluid.
• Platelet-rich plasma (PRP), prepared from the patient's own blood, which he noted has become popular.
• Ozone therapy and oxygen therapy.

His qualification was the important part: all of these are known for the early stages of arthritis. They are not a substitute for surgery in a joint that has lost its cartilage. Guideline bodies differ in how strongly they support hyaluronic acid and PRP, and ozone therapy is not part of mainstream guideline recommendations.

High tibial osteotomy: who is a candidate and what it achieves

A high tibial osteotomy suits a patient with middle-stage arthritis in one compartment of the knee, most often a bow-legged knee worn on the inner side, after medical management and lifestyle measures have been tried. Dr. Bohra offers it as surgery that changes the mechanics of the knee rather than replacing it.

A high tibial osteotomy (HTO) is what he calls alignment surgery. It is used for unicompartmental arthritis, in which only one compartment of the knee is worn. The surgeon cuts the bone on the tibial side, just below the knee, and realigns the leg. In the usual technique, a wedge of bone is opened or closed at the top of the tibia and fixed with a plate, so that the line of weight-bearing moves from the worn compartment to the healthier one. Jivo Healthcare's corrective osteotomy cost page sets out typical price ranges for alignment surgery of this kind.

The effect Dr. Bohra described is twofold. The transfer of body weight through the knee becomes normal again, as it was before the deformity developed, and the progression of the arthritis slows. Depending on the stage of the arthritis at the time of surgery, the patient may gain five, ten or fifteen years before any further operation is needed.

Partial knee replacement: what it involves and recovery time

A partial knee replacement resurfaces only the worn compartment of the knee; in Dr. Bohra's description it can be done as day-care surgery, with a return to work within a week. When one side of the knee is too far gone for alignment surgery, the next option is a partial knee replacement, also called a partial knee arthroplasty or unicompartmental knee replacement. Only the damaged half of the joint is involved. The worn surfaces of that compartment are replaced with implant components, and the rest of the knee, including the healthy compartments and the cruciate ligaments, is preserved.

Dr. Bohra stressed how small and quick the operation is:

• It is a very quick surgery, and it can even be done as day-care surgery.
• It is performed through minimally invasive surgery (MIS): a very small incision, through which the implant is placed, and a very small amount of bone removed.
• The patient can become normal within a couple of days.
• A working patient, a professor in his example, can return to duty within a week.
• Within a month, the patient can sit on the ground, swim and return to everything else.

Despite the small operation, the post-operative X-rays he showed demonstrated full correction of the affected compartment.

Partial knee replacement vs high tibial osteotomy: how they compare

High tibial osteotomy preserves the whole natural joint and suits middle-stage disease; partial knee replacement resurfaces the worn compartment when it is too far gone for realignment.

Both operations depend on the same condition: the rest of the knee must still be healthy. Once arthritis spreads across the whole joint, neither is suitable and the decision moves to total knee replacement for stage 4 osteoarthritis.

When to refer for partial knee replacement

Refer while the arthritis is still confined to one side of the knee, because that is when a partial replacement remains possible. Dr. Bohra closed this part of his lecture with a direct message to the audience. Many younger patients now present with arthritis of the medial or lateral compartment of the knee only, with the rest of the joint still intact. If those patients are identified on time and referred on time, a partial knee replacement can be life-changing: they become pain-free and close to normal, with a much smaller operation than a total replacement.

The window does not stay open. Osteoarthritis is progressive, and arthritis that starts in one compartment can spread to involve the whole knee, at which point total replacement becomes the only surgical option. For a referring doctor, the practical step is to X-ray the painful knee early, recognise when the damage is confined to one side, and refer while the choice still exists.

Doctors at the session also asked about vitamin D, juvenile arthritis and cost; Dr. Bohra's answers are on the Live Discussion page.