100%yes ! Either there is a false implantation of components or an impingement of bone or tissue which provokes the late dislocation. In each case the path is laid for recurrent dislocation and you have to make a revision NOW.

Thanks for response. I fully agree with that, still i see tendency among my colleagues to treat non-operatively for 4-6 weeks, with forced abduction.

Definitely a revision needed. There is either malposition / mal-rotation of the components of soft tissue imbalance. These issues have to be examined and addressed accordingly. Early dislocation also maybe indication of early infection.

I think really that revision is needed in this case; dual mobility will ring you the security of no more dislocation

Dr. Kuik, first of all you should diagnose what is the reason of redislocstion. If the components are properly implanted, then the reason is muscle imbalance. This situation is more difficult to cure.Perhaps that is why some colleagues count upon 4-6 weeks rest and avoiding rotation and addiction. Unfortunately, the outcome will not be good. Let me be a bad prophet.

The patient admitted that dislocation occurred while she tried to reach something on the floor and hip flexion was over 90 deg. It was during supervised rehabilitation so it shouldn't happen. The components arrangment seems fine - it is cemented stem with long head and trabecular metal acetabulum with augment.

Just a few days after reposition the patient was walking with crutches and in assist of phisiotherapist. She was extensively educated what moves to avoid. We probably will revise it to dual-mobility prosthesis in the case of second dislocation.

Education is very important too. You could try a hip protector as outer stabilizer. 

Originally was mentioned that on manipulation/relocation the prosthesis was found unstable and this new information was not included. On the recent entry were mentioned also some of the characteristics of the prosthesis.  Offset was not mentioned. 

Long neck could mean the following or combination of the following. 

Soft tissues (and mainly abductors) are inadequate due their quality 

Acetabular component positioned higher than the centre of rotation

Acetabular component is in more than 60 degrees inclination. 

All these could lead to pivotal impingement and produce dislocation. 

Please reflect back to what movements made during the relocation the joint unstable.

If she is mobilising safely ( and I agree with Panayot having an abduction brace for 6 weeks would be good as you teach the patient even when nobody is around ) wait.

In case of new dislocation having your plan based on your reflective analysis, you proceed to revision of either secure clip on cup, posterior lip augmentation, or as mentioned dual mobility cup.

All these are hypothetical solutions as you are with the patient and you only could review xrays and movement 

Which approaches were used for index surgery and for revision surgery? Time period between index and revision surgery? Soft tissue imbalance could be the challenge. Was a skirted head used (long head is incomplete info)? That skirting could be impinging! What were the offsets as compared to opposite hip?  Non-restoration of offsets could be the cause of instability. The abduction instability mentioned in the initial question could be because of low horizontal offset leading to abduction impingement. Are the adductors too tight? Component malposition has already been mentioned by others, which is the commonest cause.

So many questions need to be answered before deciding definitive treatment as establishing the cause of recurrent instability is essential before venturing into any further revision surgery.

The lack of images and insufficient clinical info provided (that too piecemeal) does discourage the readers to provide more definitive answers!!!