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Anatomical Arthroplasty for High-Flexion Asian Joint Replacement
Anatomical Arthroplasty for High-Flexion Asian Joint Replacement
Standard Western orthopaedic texts often fail to address the specific anatomical and cultural demands of the Southeast Asian patient. Restoring physiological function in this demographic requires novel techniques to accommodate extremes of motion.
Materials and Biomechanics
Materials and Biomechanics
The Hip: Traditionally uses a 28mm head for wear/stability balance. Asian motion demands require larger heads to prevent dislocation.
Ceramic Liners: Preferred for safety and accommodating larger head diameters.
Avoidances: Metal-on-metal (hypersensitivity) and brittle cross-linked polyethylene.
The Knee: More than a hinge; involves complex rotation and coronal shifting.
Kinematics: Standard designs manage 0°–120°. Deep flexion requires rotatory mechanisms.
Preferred Design: "Ball and socket" knee mechanisms over standard rotating platforms to replicate physiological rotation.
Blood Management: The 1.5L Threshold
Blood Management: The 1.5L Threshold
Peri-operative loss typically reaches 1.5L. For patients restricted from heterologous transfusions (e.g., Jehovah’s Witnesses):
Real-time Re-transfusion: We utilize drainage devices that filter and return the patient's own blood as it is lost.
Expected Recovery: Approximately 500ml over 24 hours.
The High-Wear Patient (Aged 50–60)
The High-Wear Patient (Aged 50–60)
Active males desiring high-impact activities (marathons, jogging) are poor candidates for standard arthroplasty due to polyethylene wear and ceramic fracture risks.
Alternative: High Tibial Osteotomy (HTO).
Objective: Offload diseased segments while preserving the native joint and range of motion.
Principle: Treat the patient's function, not the X-ray.
Conclusion
Conclusion
Standard Western technology is designed for Western lifestyles. With the Eastern patient load exceeding half the global population, we prioritize high-flexion designs and muscle-sparing approaches to restore the extreme ranges of motion required in the Asian context. Developed through the practice of Dr. Saminathan Suresh Nathan, this approach ensures anatomical and cultural integrity.
Figure 1. (a) A standard hip replacement illustrating the components used. Of note are the ceramic liners, a novel concept which reduces wear and allows for larger heads. (b) A standard total condylar knee design. Each femoral condyle is based on its own radius of curvature. (c) A revision knee replacement device highlighting a rotating platform (arrowed) that allows for greater range of motion. (d) Another competing concept to the rotating platform being a single mediolateral radius (as opposed to b. above) which converts a knee to a ball and socket type joint offering greater range of motion. (e) Drainage devices such as this allow for the blood that drains from the joint of an arthroplasty patient in the peri-operative period to be re-transfused into the patient.
Figure 2. This patient had a sarcoma of her right femur diagnosed on Xray (a) and was offered an amputation due to the massive size (b) in her country of origin. She elected to die with her tumor due to the requirements of her faith. However as the pain became unbearable she travelled from her home in the Middle East and presented to the author’s unit for a limb salvage procedure. The tumor was resected completely and reconstructed with the kind of joint replacement featured in 1(c).
Figure 3. (a) The patient has had both knees replaced using a standard knee replacement endoprosthesis. Her patella was not resurfaced. She was readily able to get into a kneeling posture. (b). This patient has had her right hip replaced. Although not advocated by the author, the patient hailed from a culture that was used to kneeling in this fashion for prayer. She had had a ceramic on ceramic implant inserted which allowed for a bigger head to be used for stability. In addition the hip was replaced through a small anterior incision of 7 cm length (MIS or minimally invasive surgery) which allowed for this kind of posture without the risk of dislocation.
Figure 4. This patient had both knees replaced at the same sitting using the high flexion designs featured in 1d above. Preoperatively she had good range of motion in the knee and was keen on retaining this range of motion for prayer.
Figure 5. All three of these patients were able to squat following surgery with three different kinds of hi-flexion knee designs. (a,b) This patient has a traditional knee replacement with a prosthesis that has a smaller medio-lateral dimension allowing the knee to flex deeply without too much tension. (c,d) This patient has a prosthesis of the rotating platform type featured in 1c above. (e,f) This patient had both knees replaced at the same sitting with a prosthesis of the ‘ball and socket type’ featured in 1d above.
Figure 6. The older high wear patient. (a,b,c)This patient is a yoga instructor with severe osteoarthritis in the knee. He had sought multiple opinions including the author’s who concurred that a knee replacement would be the best option for him. However, this would have resulted in a loss of range of motion and high impact sport for the patient. Knowing that this procedure might be associated with residual pain, the patient underwent bilateral high tibial osteotomies at the same sitting and had good pain relief and was able to perform all pre-operative activities. (d) This older patient with knee arthritis was also offered a knee replacement but was not willing to give up running. He underwent bilateral high tibial osteotomies at the same sitting (e). 2 years after surgery the patient runs in marathons at the age of 60 years (f).
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