Masterclass 1 - Limb Prosthesis –- Where Are We Now in HA? What Is the Way Forward?

Humans have a long history of using prosthetics with evidence dating its origins back to Ancient Egypt. (Ribeiro et al. 221).  Its use has always been for function, cosmetic appearance, and a psycho-spiritual holism for an individual. Overtime, the appearance, engineering, and materials have developed and improved but its core goals remain largely the same for an individual. This report discusses the recent  development in prosthetic fitting  design through case examples to illustrate the importance of application of new technology to help our amputees integrate into community in rehabilitation.

Lower Limb prosthesis starts it’s mark in history using self-invented components with simple material like wood and metal. Over the past century, there is a considerable evolution in the design and material of lower limb prosthetics. 
This presentation looks into Lower Limb Prosthetics in Hong Kong. Aspects like socket technology to main prosthetic component like prosthetic knee joint are covered. Evolution of these components, advantages and disadvantages are covered.
A transfemoral amputee is used as an illustration where he is fitted with a mechanical, pneumatic and microprocessor knee joint. Effect of these three different type of knee joint on walking, turning and stairs walking is illustrated.

In Hong Kong, there were more than 200 diabetic-related major lower extremity amputations annually. Up to three-quarters of patients undergoing lower extremity amputation have prosthesis-fit issues including development of skin ulcers or intolerable perspiration. 
Osseointegration surgery for amputees refers to the implantation of a direct metal-to-bone anchorage in the appendicular skeleton as a platform to connect with an external prosthesis. This bypasses the traditional prosthetic-residuum interface and eliminates the prosthesis fitting problems related to skin and soft tissue. The indications are for amputees related to trauma or cancer causes who are not suitable for standard prosthesis. 
Gait analysis of transfemoral amputees fitted with an osseointegrated fixation was different compared with conventional socket users in the cadence (2% quicker), the duration of the gait cycle (3% shorter), support phases (6% shorter), and swing phases (1% longer). For clinical outcome, Branemark (N=55) and Hagberg (N=39) reported improvement in the questionnaire for Person with a Transfemoral Amputation (Q-TFA) and the Short-Form (SF)-36 at 2 years after the second stage compared with pre-operation. 
Safety of the osseointegrated implants had been reported in several case series. Branemark reported a total of 101 complications in 55 transfemoral amputations (51 patients). 8 legs (5 patients) were complication-free. Superficial infections were the most common complications, which were treated with oral antibiotics. 
There are currently two transfemoral amputations with osseointegration undergoing rehabilitation in Hong Kong. The first patient received a two-stage osseointegration surgery overseas and the second patient received a single-stage osseointegration surgery in Hong Kong. The first patient had soft tissue trimming surgery performed for soft tissue redundancy one year after the index surgery. Both patients noted improvement in their mobility and prosthetic usage compared to socket prostheses.
In conclusion, osseointegration, since its early inception over 3 decades ago, appears to be gaining greater acceptance due to the continuous refinement of surgical techniques and implants. The problem of infection, which was a significant hindrance to the widespread use of this technology previously, will gradually improve with a better understanding of the technology and future research. 

Prosthetic components will replace a lost limb and restore function to the individual. From a carved wooden leg to a new composite materials , prostheses become stronger, lighter and more functional. Appropriate prosthetic design and rehabilitation training can increase amputees activities. Prosthetists should pay attention on the choices of prosthetic components to meet patients requirements. For example,  the application of carbon fiber composite materials to prosthetic feet allow amputee to run, hiking and dancing. A J-shaped carbon spring design allows the spring to compress causing energy storage when it is loaded with the amputee weight and to return that energy as the spring is unloaded.