Safety of the Hemiverse Shoulder Prothesis

This clinical trial investigates the safety and the preliminary clinical benefit of the hemiverse shoulder prosthesis. Implantation of this newly developed hemi-prosthesis is intended for patients who do not qualify for a regular reverse or hemi-prosthesis due to severe medical conditions, poor bone stock or critical status of the rotator cuff. The expected benefit is, that patients will have a minimally invasive surgical procedure, only addressing the humeral shaft, however with the biomechanical advantage of a total reverse shoulder prosthesis, meaning, that with a minimally invasive surgery a comparable result as with a regular total shoulder prosthesis is accomplished. Patients will be closely monitored within the study protocol for 18 months and thereafter in regular interval was as with a normal prosthetic followup.

This clinical trial investigates the safety and the preliminary clinical benefit of the hemiverse shoulder prosthesis. Implantation of this newly developed hemi-prosthesis is intended for patients who do not qualify for a regular reverse or hemi-prosthesis due to severe medical conditions, poor bone stock or critical status of the rotator cuff. To evaluate the clinical condition of the patient a clinical examination with thorough control of the blood parameters (hemoglobin, leucocytes, platelets, infection parameters) and including constant score and the quick dash score will be performed before the operation. To evaluate the bone stock and the musculature a conventional radiological status and a computed tomography of the shoulder will be performed.

Surgical procedure: A delto-pectoral approach is preferred. The incision starts immediately lateral to the coracoid tip and extends to the insertion of the deltoid on the Humerus. The subscapularis tendon is exposed and detached from the humerus. The humeral head is exposed and dislocated from the joint using an oscillating saw the humeral head is resected. The shaft is prepared to receive a regular humeral stem which is definitely implanted with 0° retroversion. A trial implant is inserted and reduced into the joint. Free mobility of the joint is tested and the stability of the implant documented. According to the trial implants the definite implant is assembled and implanted. After reduction of the implant the subscapularis tendon is reattached to the humerus using transosseous sutures. Regular closure of the incision is performed.

After-care:

Immediately post operatively a anteroposterior radiograph is performed. For the first two post-operative weeks the arm is immobilised in a sling and external rotation is allowed until 0° and flexion until 90° in internal rotation. Thereafter gradual increase of active mobility is allowed until the weeks post operatively, when full load bearing of the arm is allowed. Regular followup visits include a constant score, quick dash-score and conventional radiographic status(anteroposterior lateral and axillary view) and are performed to be post-operative 3 months 6 months 1 year and 18 months post operatively.

Eligibility Criteria:
Inclusion Criteria:

* Patients aged ≥65 years
* Shoulder joint destruction in which known alternatives would constitute either a high patient risk or a high functional failure risk.
* Shoulder destruction suited for hemiarthroplasty except for present cuff failure
* Shoulder destruction for which reverse total shoulder replacement would be a high risk for medical reasons (longer operation, more blood loss) or for advanced glenoid bone destruction
* Written informed consent

Exclusion Criteria:

* Acute or chronic infection Clinical chemistry: C reactive protein \<1.5 mg/dl), possible inclusion is under investigator decision.
* Neuroarthropathy
* Moderate to severe motor axillary nerve dysfunction
* Moderate to severe destruction of deltoid muscle
* Fracture of the scapular spine or displaced fracture of the basis of the acromion
* Destruction of more than superior one third of the humeral shaft
* Hematology: hemoglobin (\<10 and \>16 g/dl), Hematocrit (\<36 and \>-48%), Anticoagulation
* Poorly controlled diabetes mellitus type I
* Immunosuppressive drugs
* Chronic inflammatory diseases, which the PI estimates contribute to a higher risk of surgery complications
* Inability to cooperate with postoperative regimen or to understand the trial information (dementia)