WILMER Open Fitting

Children with a forearm reduction defect are routinely fitted with a full contact Münster socket. This socket has three major disadvantages:

  • the socket is often not adequately fitted. The fitting procedure is difficult and requires a lot of skill and experience of the prosthetist.
  • the rigid topographical shape of the socket is a compromise between an optimal fixation of the prosthesis to the remaining limb and the ease of donning and doffing.
  • the socket envelopes the residual limb for the greater part, thus causing perspiration problems and skin irritation.

The WILMER open fitting is based on a careful study of the force transfer between the residual limb and the prosthesis. The minimal areas required for a good fixation are determined. Two rings enveloping the residual forearm, together with an upper arm brace constitute the socket. This construction leaves 75% of the skin uncovered. The socket is made of stainless steel tubes, covered with soft foam to ensure comfort of wearing. To ease donning and doffing, the upper arm brace can be shifted away of the two rings. By moving the condyle brace proximal additional space is created in two directions: medial-lateral in order to give way to the condyles and distal-proximal concerning the residual limb. The upper arm brace can be locked in several positions; this enables the user to tighten or loosen the socket. Moreover, the socket is adjustable to the growth of the child. The open fitting is build directly onto the patient, without the interference of a plaster cast. The fitting procedure substantially increases the number of correctly fitted sockets. Before definite fixation of the socket components, the patient tests the socket under loading conditions.


  • for children and adults with forearm reduction defects 


  • adjustable forearm socket
  • major reduction of perspiration problems
  • skin at elbow region minimally covered
  • cherished ease of donning and doffing
  • insensitive to sand, water and dirt
  • available as assembly kit, suited for WILMER elbow control and for shoulder control
  • offers 20 locking positions in steps of 1,3 mm