What can I do if my Patient is not Extending his Knee During Stance Phase?
As you have probably experienced, some patients lack knee extension during stance phase. Lack of knee extension may be caused by different reasons. The Lokomat provides a number of adjustments to ensure proper gait kinematics during walking; the challenge is identifying the cause so as to properly adjust. Below are a few considerations in order to make sure the patient has good knee extension during stance phase.
1. Are the cuffs properly tightened?
Check if the cuffs are loose, particularly the upper cuff. They need to be properly tightened.
2. Is the height of the Lokomat knee axis properly adjusted to the patient?
Double check the knee height. If the knee axis of the Lokomat is below the knee axis of your patient this may cause your patient to be “pushed down” during stance phase. If this is the case, double check (a) that the hip axis height is correctly aligned and (b) whether you set the upper leg too long.
3. Did you properly adjust the sagittal plane setting?
When the Lokomat orthosis is fully extended, the patient’s knee should be too. This is particularly visible at the end of the swing phase. If this is not the case, lift the patient, click on “stop” and re-adjust the sagittal settings by moving the lower cuff forwards. Before starting again, check the knee extension by manually moving the orthosis.
A patient’s knee can be extended during stance phase by moving the upper cuff backwards. As you are adjusting the cuffs, ensure that you are not hyperextending the patient’s knee.
4. Is the BWS value appropriate?
It might be the case that either the BWS value is too high or too low. If it’s too low, the patient cannot support his own weight and his knees will buckle. If the BWS value is set too high, the patient won’t have enough loading to activate a muscle response.
5. Is the patient walking with dynamic BWS enabled?
Make sure the patient is walking within the dynamic range of the body weight support. This is necessary for the patient to have enough loading. Using a static range means he is still “lifted”. This is also important to ensure constant support, as vertical displacement on the gait cycle needs to be adapted in order to avoid extreme variations on the value.
You can ensure the patient remains in a dynamic range by using the automatic dynamic function (“dyn”). This is particularly useful when changing the value of BWS.
6. Is the patient not actively participating or getting tired?
Make sure the patient stays alert and maintains effort during walking. Your patient must remain as active as possible in the Lokomat orthosis during stance phase. Verbal and physical cues to “stand up” or “be tall” might be helpful.
If the patient is tiring out, you can increase the body weight support or guidance force. If that doesn’t work, it might be time to end the session.
Safe Walk Adjustments
Please note that this video shows the safe walk adjustments with the Lokocontrol Software V6.2 with the FreeD module.
If you are using a different software on your Lokomat, the adjustments are still the same, you only have a different software interface.