Bloch H. R. MD °, De Biase Carlo Felice MD *, Burelli S. MS °

° Medical Scientific Department, LIMA Corporate, I-33038 Villanova di San Daniele del Friuli (UD) Italy * San Carlo di Nancy Hospital, Via Aurelia 275, 00165 Rome, Italy

INTRODUCTION

The number of shoulders replaced compared to hip and knee replacement is small; but the increased number of shoulder arthroplasties performed raises concern, taking over the lessons learned by the greater number of failing hip and knee replacement, revision procedures. Revising a shoulder arthroplasty present challenges diagnostically and surgically. Failure result from bony deficiencies, soft tissue failure, component loosening and infection. Glenoid component loosening has been recognized as a common reason for failure even if revision surgery is more frequent for painful glenoid arthritis after hemiarthroplasty. Conversion of humeral head replacement to total shoulder arthroplasty can give good results. Whenever structurally possible, reimplanting a glenoid component shows better clinical results concerning pain relief, ROM and patient satisfaction. Loosening of the stem as a primary cause of revision surgery is rarely reported. Stem revision provides reliable pain relief and modest improvement of function but risk of intraoperative complications are high.

Revision to a Reverse Total Shoulder Arthroplasty in case of glenoid component failure and irreparable cuff situation can restore pain relief and function. For selected disabling shoulders in revision situation, reverse total shoulder arthroplasty is a concern if glenoid replacement is mechanically possible. Patients with important pain and loss of function following shoulder arthroplasty have limited reliable treatment options. In case of bone loss, glenoid reconstruction with an allograft composite and the use of special glenoid component with reconstruction plate is an option, regaining stable fixation providing with the reverse system an acceptable ROM and pain relief to the patient. 

PROCEDURE and ALGORITHM

Pain, bone deficiencies, loss of function and patient dissatisfaction constitute the unsatisfactory shoulder. Patient’s concomitant internal problems, age and compliance present basic to decide after a clear local statement above revision

possibilities.Specific surgical techniques dealing with revision of different types of prosthesis are needed. First, the infection situation must be cleared up. Problems of bone infection are universal; especially lowgrade infection is becoming more recognized as a cause of failure in shoulder arthroplasty. Planning revision surgery, recent radiological investigations are needed, so as a basic radiological exam (ap-view in internal and external rotation, axial or Bernageau view) so as CT scan with 3D reconstruction. In case of infection and/or loosening situation, scintigraphic evaluation could be helpful.In case of bone loss, osseous defects should be reconstructed by bone graft. Patients also with acquired bone defects can have clinical outcomes comparable with those in patients with normal glenoid morphology due to a modified surgical technique.The level and location of bone loss is one of the most important part of preoperative surgical planning. In a modular system, revision surgery is easier because it permits the surgeons to change only parts of the prosthetic implant (and so reducing OP time and complication rate).

 

 

SURGICAL PROCEDURE

Inadequate bone stock is recognised after explantation of the present glenoid system. Glenoid bone must support the new implant, so grafting is mandatory, otherwise decreased functional outcomes and early failure are common.

Exposition of the rest of the glenoid bone to recognise scapular spine centerline is the first step. Covering bone loss, previous fixation by K-wire or 2.7mm cannulated screws are the following. Metal back base plate is now implanted in the scapular body along the spine centreline, providing a stable fixation.

Further bone graft stabilisation is achieved using the glenoid reconstruction plate which gives an additional stabilisation of the bone graft against scapular body and metal back. Insertion of the glenosphere and prosthetic joint reposition completes the procedure.

 

 

CONCLUSION

Acquired bone defects in revision surgery are common and require bone grafting to provide a stable fixation of the metal back base plate. Metal back base plate with new materials (TT) so as the new glenoid reconstruction plate are very helpful to surgeons. Larger glenosphere as the 40mm and 44 mm glenosphere can accommodate for bone loss and appropriately tension of the remaining soft tissue.

Greater surface contact area between the glenosphere in conjunction with the reversal of the articulation neutralizes the destabilizing force of the deltoid and enables the metal back to be relatively anteverted.

Preserving as much as possible of the pectoralis major and subscapularis, ROM and joint stability will be better and so clinical outcome and patients satisfaction.