Evaluation of a reconstruction reverse shoulder for tumour surgery and tribological comparision with an anatomical shoulder arthroplasty

Abstract

Purpose The functional results after reconstruction of the proximal humerus in tumour surgery are poor. Therefore, a reversed proximal humerus replacement was developed in our institution (MUTARS humerus inverse). A low degree of wear on the polyethylene is required because of the patients' youth and demands on shoulder function. A special type of polyethylene with shock-absorbing properties has been developed to minimise polyethylene wear in the MUTARS inverse proximal humerus replacement. We compared the tribological properties of an anatomical shoulder prosthesis (CAPICA) with the new reversed proximal humerus replacement (MUTARS humerus inverse). Methods Both prostheses were tested up to 5×10 6 cycles. Every millionth cycle the surface was inspected and a gravimetric measurement was performed. A measurement of surface roughness was done before testing and after 5×10 6 cycles. Results In both prostheses after 5×10 6 cycles there were no major defects, such as delamination, observed. In the reversed proximal humerus replacement abrasion of 28 mg/ 10 6 cycles was detected. The mean abrasion of the anatomical prosthesis was 9.28 mg/ 10 6 cycles. Conclusion The glenoid component of the first reversed humerus replacement (MUTARS humerus inverse) has wear properties comparable to those of normal reversed shoulder prostheses. This is important, as this type of prosthesis is used in young patients after resection of bone tumours, with a good functional outcome. It can, therefore, be expected that the revision rate due to wear will be as high as in patients with normal reversed shoulder prostheses.

Improvement of the shoulder function after large segment resection of the proximal humerus with the use of an inverse tumour prosthesis

“…Although an in-vitro study of our research group detected more PE particles in the inverse proximal humerus implant compared to anatomical-shaped shoulder prostheses, the amount of debris was within acceptable values and comparable to other inverse implants [24]. Other regularly seen complications, like acromial insufficiency, glenosphere disengagement or scapula fractures, which are described by Scarlat in his review investigating the complications with reverse shoulder arthroplasty [25], did not appear in our series.…”

Complications with reverse total shoulder arthroplasty and recent evolutions

“…Indications for RTSA include degenerative arthritis associated with irreparable cuff tears (cuff tear arthropathy) and irreparable cuff tears with loss of function in the elderly (pseudoparalytic shoulder) [3][4][5][6][7][8][9], aseptic necrosis of the humeral head in the elderly [1], shoulder reconstruction in rheumatoid arthritis [5,10], chronic shoulder dislocations in the elderly [11], reconstruction surgery for tumour [12,13], revision surgery after failed anatomical or resurfacing arthroplasty [14][15][16][17][18][19], failed rotator cuff repair with superior escape and reconstruction for comminuted fractures of the proximal humerus in the elderly [20,21]. Any procedure addressing shoulder reconstruction with RTSA demands the existence of a functional deltoid muscle that makes shoulder mobility possible with this type of implant [20].…”

Clinical and radiological outcome of the Total Evolutive Shoulder System (TESS®) reverse shoulder arthroplasty: a prospective comparative non-randomised study

“…Besides CTA, the indications for RSA include comminuted shoulder fractures, revisions, rheumatoid arthritis (RA) and severe osteoarthritis (OA) [2][3][4].…”