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Helix3D Hip Joint Component Selection Requirements 

Otto Bock Healthcare


 

Due to missing hip muscles resulting from hip disarticuation or hemipelvectomy amputation, patients are unable to bring the knee into extension or provide heel strike onto the ground in a targeted manner.  Therefore, knee joints requiring hip extension or a certain amount of force to be applied on the heel to achieve stance phase stability are contraindicated.  The stance resistance of the C-Leg does not require stabilization of the knee through hip extensor activity or by loading of the heel in a certain manner, thereby ensuring its stability.

 

In addition, the flexion springs of the Helix3D Hip Joint are designed to provide a strong flexion bias to the hip.  It has been found that the entire prosthetic leg when lifted off the floor moves forward which is caused by the hip flexion bias. This forward motion of the limb can result in slight flexion of the knee and can in some cases, lead to an unsafe situation for the patient if they put weight into the limb while the knee is flexed. This unsafe situation can arise if the knee joint does not have a high flexion resistance engaged to accommodate the patient’s weight. Therefore, knees which utilize a weight activated stance control are also contraindicated since the high flexion resistance will not be present. With the C-Leg, the high flexion resistance will remain engaged in the situation mentioned above and it will therefore remain stable for the patient.

 

Furthermore, knee joints without swing and stance extension damping are also contraindicated for use with the Helix3D Hip Joint. Due to the strong flexion bias of the Helix3D Hip Joint, there will be a strong extension movement passed to the knee during swing phase. This movement requires a properly set swing extension resistance to provide the exact timing for full extension of the knee during swing phase in order to ensure that the foot will be in the proper position at heel strike. In addition, since the Helix3D Hip Joint works to encourage and support knee flexion during loading response, if the knee lacks stance extension damping, the patient will have a very uncomfortable movement of the knee back into full extension during mid-stance and terminal stance. The C-Leg has both swing and stance extension damping that can be set by the practitioner to the proper level of resistance.

 

When choosing components for a complete prosthesis, the practitioner must choose a knee joint that provides 1) absolute stability and reliability at heel strike, 2) stance extension damping, and 3) swing extension damping.


 

Otto Bock is of the opinion that only the C-Leg® meets these criteria.  Further, Otto Bock has only tested the Helix3D Hip Joint with the C-Leg® knee joint.  Accordingly, Otto Bock requires that the Helix3D Hip Joint may only be combined with the C-Leg® and the prosthetic feet specified for use with the C-Leg® and other components specified in the Instructions for Use (p. 23).

 

The Helix3D Hip Joint’s functions are specially adapted to the characteristics of selected Otto Bock components.  Safe and proper function of the Helix3D Hip Joint can only be guaranteed if it is used in combination with those components recommended by Otto Bock. 

 

Otto Bock recommends using the Helix3D Hip Joint only under the specified conditions and for the intended purpose.  The Helix3D Hip Joint must be fit and maintained strictly in accordance with the Instructions for Use. Use of any components with the Helix3D Hip Joint other than those manufactured or recommended by Otto Bock will void the manufactures limited warranty and Otto Bock disclaims any liability for damage caused by the use of component combinations that are not recommended by the manufacturer.

Documents:

 

HELIX-Hip-Clinical-Study.pdf

 

 

HELIX-3D-Spec-Sheet-Oct-2008.pdf

 

 

HELIX-3D-Suggested-L-Codes-Oct-2008.pdf

 

 

 

 



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