Reverse - Shoulder for TraumaIndicationThe indication for reverse shoulder prosthesis in shoulder trauma remains contentious. Consider primary reverse prosthesis in elderly patients (age is relative, >75 yrs) with 4 part fractures of the proximal humerus. Hemiarthroplasty for trauma is good for pain relief but will not return normal shoulder function. Notably loss of elevation. On average a hemiarthroplasty for trauma will result in 90 degrees of elevation. Outcome following hemiarthroplastyf for trauma is variable and dependant on tuberosity healing. AnatomyThe axillary nerve arises from the posterior cord of the brachial plexus and passes through the quadrilateral space. Identify/ palpate it in the subcoracoid space.
The musculocutaneous nerve enters the conjoint tendon, beware of injury when placing retractors in the subcoracoid space under the conjoint tendon.
ConsiderationsConsider hemiarthroplasty
Exposure Antero superior, mckenzie - Eckland superior approach Deltopectoral - Gerber deltopectoral
Avoid prolonged abduction, external rotation and extension viz. traction on brachial plexus.
PositioningBeach-chair (see shoulder arthroscopy positioning)
Skin IncisionDepends on your approach.
Superficial dissectionAs for approach, with superior approach Anders Eckland splits deltoid and then takes it with a small fragment of the acromion.
Deep dissectionPlace blunt hohman under deltoid, expose down to deltoid tuberosity. Develop split in tuberosities into the rotator cuff, tenotomise biceps if present, excise supraspinatus. Remove the head fragment. Prepare humerus with standard instruments, leave rasp in situ for later trials. Insert humerus in neutral version ( 0- 20 degrees of retroversion).
Expose glenoid See Total shoudler replacement for glenoid exposure. Remove labrum and release capsule anterior, superior and posterior. Release long head of triceps off the inferior glenoid. Must expose inferior aspect of glenoid well. Expose lateral column of scapula and place forked retractor below glenoid. Place guide wire (NB Dont tilt base plate up) better to point slightly down (Be aware of superior glenoid bone loss). Remove cartilage with curette. Ream glenoid, just touch the glenoid retain subchondral bone.
Insertion of baseplate Review CT Bone stock Drill inferior screw horizontal, perpendicular to glenoid face (normally 36-48) Superior screw see CT, aim for base of coracoid (slightly up) (normally 18 - 32) Impact base plate place inferior screw first, move back and forth between screws to snuggle base plate down and avoid tilting in any particular direction, then lock screws.
Insert glenoid (male 40, female 36) as big as will tolerate. (At X tend meeting most suggesting 42mm)
Assemble trial with Zimmer anatomic use blue liner (one that medializes shaft) Reduce with traction slight flexion and IR.
Place definitive stem and TRIAL again with insert 3 mm longer before assembling polyethylene.
Exposure extension
Closure
When repairing Subscapularis remember, centre of rotation is medialized to the glenoid as opposed to centre of head, hence when externally rotate arm, subscapularis excursion is dramatically increased and limits ER. Subscapularis is needed if patient wants to place arm behind their back. Hence try repair but don't overtighten (Check ER possible to at least 0).
Tuberosity repair (Eckland) Two drill holes lateral shaft, two drill holes anterior shaft. Pass a suture through the implant pass around the tuberosities and cerclage them at the end. Place two sets of sutures through each the lateral and the anterior holes. Pass these up through the tuberosities to secure greater and lesser tuberosities to the shaft , overlap the tuberosities a little on the shaft.
Post operativelyEckland Rest in sling 2 weeks then assisted elevation to 4 weeks then start rotation.
References
Personal thoughts
Zimmer shoulder interactions course - 2010 Stuttgart - Gerber Delta X tend 25 yrs - Madrid 2012 - Eckland Page created by: Lee Van RensburgLast updated 11/09/2015 |