Learn the Anatomic total shoulder replacement, Lima SMR stemless humerus with TT glenoid surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Anatomic total shoulder replacement, Lima SMR stemless humerus with TT glenoid surgical procedure.
Anatomical total shoulder replacements are in widespread use for the treatment of patients with arthritic shoulders. Over many years the designs have changed in light of outcomes and research, particularly related to failure mechanisms. An intact rotator cuff insertion is now recognised as essential for optimal outcome from an anatomical configuration shoulder replacement. This is because one of the functions of the rotator cuff is to depress the humeral head and centre it in the glenoid during shoulder movement, particularly elevation. In the absence the superior rotator cuff tendon supraspinatus, the humeral head rides up and migrates proximally such that it may articulate with the under surface of the acromion. This will mean there is point loading on the superior edge of a prosthetic glenoid component resulting in excessive eccentric wear and the ‘rocking horse effect’ resulting in loosening of the component. While analgesia may be adequate, function is likely to be poor and risk of glenoid component wear and loosening and hence failure is high.
Many Orthopaedic companies have developed such shoulder replacement implants. In this case, I am using the stemless humeral implant on the anatomic system from the Italian company Lima. The stemless humeral component is constructed on a 3D printer to create a single piece of trabecular titanium. Hip surgeons have used the same trabecular titanium for successful reconstruction of the hip acetabulum with impressive bony ingrowth of the implant. In the shoulder, if the patient’s proximal humeral metaphyseal bone is not too soft then impaction of the trabacular titanium core humeral implant gives excellent primary fixation and promotes future bone ingrowth securing the platform component.
This is a bone preserving procedure avoiding the need to use an intramedullary stem. The same humeral core component is used for reverse total shoulder replacement as also described in Orthoracle and this facilitates revision of an anatomic replacement to reverse. The original Lima anatomic shoulder replacement uses a metalback glenoid component, fixed with press-fit and cancellous screws, into which the polyethylene component is inserted. It is very straightforward to perform revision surgery to switch the articulating components leaving the glenoid baseplate and humeral core implants, which should be solidly fixed to bone, in place.
There have been concerns with metal glenoid baseplates concerning eccentric wear of the polyethylene resulting in the humeral head component articulating with the metal rim of the baseplate. Dissociation of the polyethylene liner from the metal baseplate has also been recognised. To reduce the risk of such problems Lima have developed the TT hybrid glenoid component. The majority of the implant is polyethylene with a central peg attached to a trabecular titanium (TT) core and two much smaller peripheral pegs to ensure rotational stability which can be fixed with a tiny volume of cement, hence the hybrid label. The central TT peg is impacted into the prepared glenoid and will encourage bone ingrowth just as the humeral core implant.
If in the future revision surgery from anatomic to reverse is required, then the system has been designed to allow the polyethylene to be drilled and dissociated from the central TT core and discarded. The central peg core is firmly embedded in the glenoid into which a male to female metal baseplate can be inserted onto which the glenosphere is fixed for the reverse geometry shoulder replacement.
Readers will also find of interest the following related OrthOracle operative techniques:
Lima stemless reverse shoulder replacement
Lima SMR Reverse Total Shoulder Replacement for proximal humeral fracture
Lima stemmed SMR reverse geometry shoulder replacement (nickel free implants)
Proximal humeral replacement: Mutars reverse geometry shoulder (Implantcast).
Clinicians should seek clarification on whether any implant demonstrated is licensed for use in their own country.
In the USA contact: https://www.fda.gov/medical-devices/products-and-medical-procedures
In the UK contact: https://www.gov.uk/government/organisations/medicines-and-healthcare-products-regulatory-agency
In the EU contact: https://www.ema.europa.eu/en/human-regulatory/overview/medical-devices
INDICATIONS
Osteoarthritis of the glenohumeral joint with an intact rotator cuff is the prime indication for this operation. Whilst such shoulder replacement arthroplasty surgery has historically been reserved for an older population, I would consider it in any patient with degenerate glenohumeral joint surfaces for whatever aetiology – osteoarthritis, rheumatoid or other inflammatory arthropathy, avascular necrosis, post-traumatic arthritis – if the rotator cuff insertions at the proximal humerus are intact. In patients with arthritis and poorly functioning or thin rotator cuff insertion, an anatomic configuration total shoulder replacement is likely to have poor outcome. In such cases it is worth considering sacrificing the superior rotator cuff and using a reverse geometry implant.
Patients with rheumatoid arthritis may also be considered for a reverse shoulder replacement as the natural history of their rotator cuff insertion is of poor function and degenerate tears.
All patients considered for a stemless humeral implant must have their proximal humeral metaphyseal bone assessed with cross-sectional imaging by MRI or CT scan. Whilst patients with acute proximal humerus fractures may be managed with a stemmed reverse shoulder replacement the likely deficiency in the proximal humeral metaphysis is a contraindication to stemless humeral implant.
SYMPTOMS & EXAMINATION
Patients usually present with gradual insidious deterioration in shoulder function and increasing pain. They will describe deep-seated pain within the shoulder girdle, perhaps radiating down the arm. On occasions there may be some swelling in comparison with the opposite shoulder indicating the presence of a joint effusion. They may describe dysfunction, an inability to raise their arm and weakness with any lifting or loading of the shoulder. They may describe previous history of an injury to the shoulder but often there has been complete absence of trauma. Usually the symptoms have come on gradually over a number of months or even years. Night pain is often a feature and they may describe crunching or clicking within the shoulder.
Clinical examination is important to compare both shoulders looking for symmetry, with respect to swelling and muscle wasting. Active and passive range of motion should be assessed and it is important to assess rotator cuff strength with resistance to elevation, external and internal rotation although pain may make this difficult. Neurological status in the upper limb is important and it is important to assess range of motion in their cervical spine, as well as elbow, wrist and hand function on the side in question.
As with any patients considered for surgical management, their past medical history and comorbidities, including medication, should be taken into consideration and carefully documented.
IMAGING
Plain Xrays are mandatory and ideally these should be 3 views: AP, lateral and axillary or modified axial views. I recommend MRI scanning in all patients undergoing shoulder replacement and I use this to reinforce my clinical findings with respect to the rotator cuff. It is important to look at subscapularis and compare this with clinical findings as this will be taken down to gain access to the shoulder and subsequently repaired. It is also possible to estimate adequacy of bone stock on MRI scan both within the glenoid and the humeral head to predict any potential concerns with respect to fixation of the implant components on both sides of the joint. Presence of geode cysts in either site may be picked up on the MRI when not easily seen on plain radiographs. Such finding may influence preoperative planning such as implant choice or need for bone grafting.
ALTERNATIVE OPERATIVE TREATMENT
Patients with minimal arthritis could be considered for arthroscopic assessment of the shoulder for debridement of unstable articular cartilage and capsular release with the aim of improving range of movement. Traditionally hemiarthroplasty, replacing the proximal humerus alone, would be considered in patients with arthritis but this is now widely accepted as having a notoriously poor outcome due to persistent pain from the prosthetic humeral head articulating with the arthritic native glenoid surface.
NON-OPERATIVE MANAGEMENT
As with all patients considered for any joint replacement surgery, conservative non-operative management should have been exhausted. Such treatment would include education of the patient as to their condition, suitable oral analgesia and anti-inflammatory medication, taking into account their medical comorbidities, and physiotherapy to optimise their function. Therapists will concentrate on a stretching and strengthening program, which can be very successful in a motivated patient to improve range of motion, function, strength and hence reduce pain. Some doctors will consider steroid and local anesthetic or hyaluronic acid injection to the shoulder, which can certainly help with acute inflammatory synovitis or arthritis.
CONTRAINDICATIONS
In patients with arthritis and absent, poorly functioning or thin rotator cuff tendons, an anatomic configuration total shoulder replacement is likely to have poor outcome. In such cases it is worth considering sacrificing any remaining superior rotator cuff and using a reverse geometry implant (see Orthoracle ‘Lima Stemless Reverse Geometry Total Shoulder Replacement’ and ‘Lima stemmed SMR reverse geometry total shoulder replacement (nickel free implants))’. General medical health and comorbidities must be taken into consideration in any patient being treated surgically for arthritic conditions. Patients must be able to comply with relatively straightforward physiotherapy in the post-operative period and ongoing rehabilitation instructions to optimise their function. In patients with significant medical comorbidities then a multidisciplinary approach with a pre-operative assessment team, often lead by a senior anaesthetist, is recommended. Relative contraindications are lack of bone stock within the glenoid and scapula but this can be addressed with either a bone grafting techniques or use of augmented or custom-built implants. Such techniques are not described here.
The procedure is performed under general anaesthetic usually supplemented with interscalene local anaesthetic nerve block, performed by the anaesthetist. The patient is placed in the semi-sitting beach chair position, with the operated arm on a moveable narrow armboard. It is often appropriate to perform a social wash of the affected shoulder and axilla prior to routine skin preparation. Unless there are contraindications, I use Flowtron intermittent calf compression during surgery to reduce the risk of thromboembolic disease. Intravenous antibiotics are administered by anaesthetist. The skin is prepared using Chlorhexidine solution, starting with the hand and preparing the whole of the upper limb and shoulder, across to the patient’s midline. Standard adhesive drapes are used to protect the patient’s airway tubing and to allow adequate exposure for approach to the shoulder from an anterior incision. With the help of a company representative, the nurses should be familiarised with the sets required for shoulder arthroplasty. I also use a standard set of shoulder retractors which significantly facilitate the operation.
General points
• The surgery is primarily performed for pain relief, function can improve but it is often secondary to a reduction in pain –allowing improved Deltoid function.
• Patient progress and outcome will ultimately depend on the condition of the joint and soft tissue pre-operatively.
• Improvement can continue for 18-24 month’s post-operatively, it is therefore important to encourage patient to continue with rehabilitation until no further improvement.
• Aim of rehabilitation is good quality of movement, and maximal function, however in this group of patients increased scapula motion is to be expected and maybe encouraged,
• Don’t sacrifice quality of movement and function for ROM
• The principles of the Deltoid Rehabilitation Programme for irreparable rotator cuffs should be utilised.
Precautions
The underlying pathology is one of chronic degenerative rotator cuff rupture; it varies from patient to patient as to what if any rotator cuff remains intact. If any tendons were repaired then this will be stated in the op notes and the rehabilitation will be guided by this.
Repetitive overhead activities and loaded activities above shoulder height may be limited long term and should not be forced with rehabilitation.
Lifting weights above shoulder height with more than 2-4 kg should be avoided unless otherwise instructed by the surgeon.
Hand behind back (HBB) should not be forced and may not be regained There is likely to be a chronic deficit in rotator cuff strength, particularly in ER.
Immobilisation
• Patient to wear sling for 3 weeks 24 hours a day, only removing for physiotherapy exercises • At 3 weeks, start to wean out of sling but to continue wearing at night for a further 3 weeks
• Total sling usage – 6 weeks
Post-Operative
0-6 weeks: Pendular exercises; Active assisted ER to neutral (ONLY IF THERE IS NO SUBSCAPULARIS REPAIR); Active assisted elevation in supine as comfort allows – consider use of table slides or walk backs
3 weeks: Gradually wean out of sling – light activities only (weight of a cup of tea within the field of vision, short lever)
6 weeks: Start to increase ER, as ER increases gradually increase elevation ROM; Active assisted exercises progressing to active exercises – utilise short lever, supine & CKC if appropriate; Don’t force HBB position; No long lever open chain exercises until 8 weeks
8 weeks: Consider use of the principles of the Deltoid Rehabilitation programme Sub maximal isometrics in neutral – avoiding any repaired tendons
12 weeks+: Isometrics in variable starting positions; Progressing to resisted through range strengthening – consider weight of arm, varied starting position & functional weights as well as theraband. REMEMBER FUNCTIONAL GOAL and the underlying pathology is massive irreparable rotator cuff tear
Ultimate aim is function rather than anatomical range of movement.
Nine-year outcome after anatomic stemless shoulder prosthesis: clinical and radiologic results. N Hawi, P Magosch, M Tauber, S Lichtenberg, P Habermeyer. J Shoulder Elbow Surg (2017) 26, 1609-1615
49 Arthrex Eclipse stemless humeral arthroplasties – 17 total joint replacement 32 hemiarthoplasty
43 followed up at mean 9 years – 7 OA, 24 post-traumatic arthritis, 7 instability, 2 cuff tear arthropathy, 1 post-infective, 2 revisions
Constant-Murley score improvement from 52% to 79%; improved elevation, abduction and external rotation; no revisions for loosening
results comparable to third- and fourth-generation standard shoulder arthroplasty
Clinical and radiologic outcomes following total shoulder arthroplasty using Arthrex Eclipse stemless humeral component with minimum 2 years’ follow-up. S Gallacher, H Williams, A King, J Kitson, C Smith, W Thomas. J Shoulder Elbow Surg (2018) 27, 2191-2197
100 consecutive cases with minimum 2 year follow up (range 2-6yrs)
mean Oxford Shoulder Score at 2 years 38/48 – mean improvement 19 points
no significant deterioration in OSS at 3 or 4 years
excellent functional and radiographic outcomes 2-6 years with accurate anatomical reproduction and no implant loosening
Sidus Stem-Free Shoulder System for primary osteoarthritis: short-term results of a multicenter study. A Krukenberg, J McBirnie, S Bartsch, N Bohler, E Wiedemann, B Jost, P Mansat, P Bellow-Champel, R Angeloni, M Scheibel. J Shoulder Elbow Surg (2018) 27, 1483-1490
148 patients (151 shoulders) between Nov 2012 and Dec 2015 in 9 European centres
80% osteoarthritis; 105 followed to 2 years – 73 total arthroplasty & 32 hemiarthroplasty
good clinical and radiological short-term results comparable with other stem-free implants
The short -term survival of total stemless shoulder arthroplasty for osteoarthritis is comparable to that of total stemmed shoulder arthroplasty: a Nordic Arthroplasty Register Association study. J Rasmussen, J Harjula, E Arverud, R Hole, S Jensen, S Brorson, A Fenstad, B Salomonsson, V Äärimaa. J Shoulder Elbow Surg (2019) 28, 1578-1586
comparison of 761 stemless and 4398 stemmed shoulder replacements from 2011 to 2016
21 (2.8%) stemless and 116 (2.6%) stemmed joints were revised – most commonly for infection
short -term survival of total stemless shoulder arthroplasty for osteoarthritis is comparable to that of total stemmed shoulder arthroplasty but longer observation time needed to assess whether equal performance persists
Reference
- orthoracle.com
