Chemical Engineer Kenneth Kingsley founded Kingsley Manufacturing in 1948 after he retired from Norris Industries. Kingsley produced a variety of plastic products including fibreglass tops for MG cars. The company moved into prosthetics in 1953, almost by chance.
In the early 1960's Otto Bock pioneered the moulded SACH foot. Kingsley was able to duplicate this molding process and avoid patent issues by changing the manufacturing process. Kingsley SACH feet came out of the mould in one piece completely finished, unlike other models in the market which came out in 3 pieces. Up until 1991 Kingsley MFG was run by Kenneth' son in-law James Truesdell. In 1977 they became the first to carve toes and throughout the 70's and 80's expanded the line to include 21 styles of SACH feet to accommodate varying heel heights of different shoes and sizes.
Jeff Kingsley took over the business in 1991 after his uncle died and has been at the helm since. He has served on the American Orthotic and Prosthetic Academy (AOPA) board of directors and served as exhibits chairman for AOPA and for the American Academy of Orthotists and Prosthetists.
The company is based in Costa Mesa California and has a comprehensive range of prosthetic foot models available.
Click here to view the Kingsley prosthetic foot range
Guide to Proper Foot Selection and Fitting
The Kingsley SACH foot is designed to be custom shaped, sanded and otherwise modified in the facility without affecting its durability or warranty.
In order for the SACH foot to function correctly, several criteria must be met.
Proper Size and Heel Height for the shoe.
Properly selected Heel Cushion Durometer.
Proper Shaping of the Foot.
To select the proper foot for the shoe being fit, measure the innersole of the shoe and subtract 1/4" - 3/8". Convert this measurement to centimetres and select the corresponding foot by centimetre length. To determine the heel rise of the shoe, measure the heel at the anterior edge, less the thickness of the sole.
The heel cushion durometer is decided upon during dynamic alignment of the prosthesis. The heel cushion should compress about 1/2" when the proper durometer cushion is selected. Medium compression should be the correct selection in all but the most unusual cases.
When fitted into the shoe, the attachment surface should be level. Should the attachment surface lean either anterior or posterior by more than 2 to 3 degrees, the heel cushion MUST be modified. At no time should the attachment surface of any foot be altered to realign the foot. Sanding or wedging of this surface will place stresses on the foot bolt that cause failures. (THIS APPLIES TO ALL SACH FEET, ESPECIALLY ENERGY STORAGE FEET!).
We recommend that, in order to make these modifications, part of the sole of the foot be cut away, the modifications completed, and the sole rebonded to the foot.
To Correct Anterior Lean
Material must be removed from the Heel Cushion Area. To determine the amount of material to remove, place shims under the sole of the shoe at the ball until the attachment surface is level. The thickness of the shims determines the amount of material to remove.
When removing material from the Heel Cushion area, begin by marking the cutting lines. The Distal line should follow the mold lines and ex lend to about 1 Anterior to the Apex of the Heel Cushion. Then mark the shim measurement and draw the proximal line at an angle that will meet the distal line. CUT THE DISTAL LINE FIRST.
In some cases, removal of Heel Cushion material will cause the arch to come into contact with the arch of the shoe. Should this occur, Create an arc in the distal cut with a tapered sanding cone. When rebonded, this will draw the sole in, accentuating the arch.
To Correct Posterior Lean
Material must be added to the Heel Cushion Area. The amount of material to be added is determined by placing shims under the heel of the shoe until the attachment surface is level. The thickness of the shims determines the amount of material to be ADDED.
When adding material to the Heel Cushion, cut the Heel Wedge along the mold lines using a band saw up to the apex of the Heel Cushion. Then using a serrated knife, continue the cut to approximately 2" anterior to the Heel Cushion. Using your shim measurements, cut a piece of Heel Cushion material and bond with a high quality neoprene contact cement. Use a tongue depressor to scrape away any excess cement from the forward edge of the cut to keep the material from bulging at that point. Roll the foot on the edge of a bench top to better bond the surfaces. Then place the foot in a plastic bag and wrap with apiece of rubber inner tube until the glue is setup. To redrill the Bolt Access Hole, sharpen apiece of 1" pipe and twist it in by hand.
CHECK AGAIN TO BE SURE THE ATTACHMENT SURFACE IS LEVEL AND CHECK FOR CORRECT FIT IN THE SHOE.
A proper fit is vitally important to both the function and the cosmetics of the SACH foot. Three key areas should be checked when fitting the foot.
Upper and lower medial arch
At Heel Strike, the Heel Cushion compresses approximately 1/2". As this compression occurs the cushion expands into the shoe, transferring it s bulk laterally and posteriorly and shifting it's apex lower in the shoe. The foot should be sanded in the upper portion of the posterior heel and contoured along the upper mold lines to provide relief in these areas.
The Lower Medial Arch should be relieved, allowing room for the foot to settle into the shoe as the Heel Cushion compresses and continues through Mid Stance.
The shaping of the Toe section of the SACH foot is also very important to the function of the foot. Room must be provided in the shoe for the toes to mend as the foot rolls over to Toe Off. The advent of prosthetic feet with natural toes introduced the problem of fitting narrow shoes without destroying the cosmetic appearance of the foot. We have found that, in most cases, these modifications can be carved out without affecting the cosmetic appearance of the toes to any great extent.
This is accomplished by narrowing the foot at the metatarsal prominences. Round and narrow the plantar surface of the toe area as necessary, taking care not to sand the Dorsal surface of the Toes. Fine sand with a pneumatic sanding drum to finish.
The foot is then fit back into the shoe and checked again for proper fit and contour. Also, check again to be sure the attachment surface is level. Especially in the case of interchangeable feet, we recommend that a pin be inserted in the keel anterior to the bolt hole to maintain proper alignment.