Notes On The Kbm Prosthesis

Hector W. Kay


The patellar-tendon-bearing (PTB) prosthesis for the below-knee amputee has become well accepted all over the world. In some centers it is the"standard" or "routine" method of fitting this type of amputation. Nevertheless, two other methods of fitting the below-knee prosthesis have aroused increasing interest during the past few years.

These two methods are the PTS (patellar-tendon-supracondylar) with which is associated the name of Guy Fajal of France; and the KBM (Kondylen Bein Muenster) developed by Dr. G. G. Kuhn at Muenster, Germany. Neither of these fitting techniques has yet been widely applied in the United States. Marschall and Nitschke of Syracuse, N.Y. have published several articles 1,2 describing their experiences in fitting the PTS prosthesis and other prosthetists in the United States are now experimenting with this procedure. Similarly, experience with KBM fittings in this country is quite limited although Fillauer of Chattanooga, Snelson of Rancho Los Amigos Hospital, and Zettl of Seattle have verbally reported favorable outcomes.

For the KBM technique particularly, very little written material is available. We were pleased, therefore, to note a reference to this item in the November 1967 issue of Orthopaedie-Technik3. Through the good offices of Kurt Marschall* in providing a translation from the German and the kind permission of H.G. Kemper** and Orthopaedie-Technik to reprint, we are able to reproduce pertinent excerpts from this material. The pictures which illustrated the original article were also provided by Herr Kemper.

Excerpts from Orthopaedie-Technik Article

"Stefan Burger, a reputable prosthetic expert, reported on one of his favorite subjects, the fitting of the below-knee amputee with the 'Kondylen Bein Muenster' (Condyle Prosthesis Muenster) (Fig. 1 and 2 ). He mentioned that this particular below-knee fitting method has had numerous predecessors, like Radcliffe, Fajal, and many more."

As to the construction of the prosthesis, he said this:

"The medial and lateral wall reach high above the level of articulation, thus enclosing the knee joint in its entirety. The stump is fitted in a slight amount of flexion and in total contact with the socket. The patella is largely exposed in contrast to the posterior wall which is kept high.

"The innovation in this prosthesis is the medial wedge which is placed above the femoral condyle securing the prosthesis to the stump in such intimacy that piston action during flexion and extension is eliminated."

Mr. Burger also pointed out that the fitting of the patient's stump is first carried out in a hard bedding (wood) until the proper weight-bearing areas are established and all pressure spots removed. Then the plastic socket with soft insert is fabricated.

"Patients previously wearing side joints and corset and displaying reluctance to abandon them are provided with light side joints and a small cuff. All in all, this represents an interesting possibility and method in the construction of a below-knee prosthesis which counteracts the predominant muscle atrophy in conventional prostheses."

*Certified Prosthetist, Empire Artificial Limbs, Inc., Syracuse, N.Y. Chairman, Vereinigung fuer Orthopaedie-Technik.

Hector W. Kay is the Assistant Executive Director of the Committee on Prosthetics Research and Development National Research Council Washington, D.C.

References:
1. Marschall, Kurt, and Nitschke, Robert, "The P.T.S. Prosthesis (Complete enclosure of patella and femoral condyles in below knee fitting)," Orthopedic and Prosthetic Appliance Journal, 20:123-126, (June) 1966. 
2. Marschall, Kurt, and Nitschke, Robert, "Principles of the Patellar Tendon Supra-Condylar Prosthesis," Orthopedic and Prosthetic Appliance Journal, 21:33-38, (March) 1967. 
3. Orthopaedie-Technik, pp. 296-298, (November) 1967.