RTSA

The Verso stemless or short metaphyseal RTSA (Images provided by Prof. Ofer Levy)

The Verso is designed purely as a RTSA. It is not a platform convertible system and therefore avoids concerns regarding additional modularity and resultant fretting, metallosis and implant breakage [11]. The Verso has a short metaphyseal humeral implant with three thin tapered fins. These are designed for impaction into the humeral metaphysis to provide immediate press-fit fixation. The implant relies on fixation in the metaphyseal cancellous bone, without the need for cortical bone fixation. Consequently, this allows for use of the Verso in the vast majority of patients. Using bone graft impaction, even those with severe osteoporosis or bone cysts can be treated with the Verso. The fins have a titanium porous and hydroxyapatite coating to allow bony ingrowth and improve the biologic fixation of the implant. The glenoid baseplate has a central tapered screw which is also hydroxyapatite-coated titanium. Two anti-rotation screws are used superiorly and inferiorly. The glenoid sphere is fixed to the baseplate with a Morse taper. Polyethylene humeral liners have a 10° inclination shape which provides a very low profile medially, thereby reducing impingement between the polyethylene liner and the glenoid neck and thus reducing the risk of scapula notching and promoting improved rotational movement. The humeral cut is performed at an angle of 155°. The inclined liner results in a final implant angle of 145°. A unique feature of the Verso implant is the ability to ‘dial’ the humeral liner so that the version and offset of the liner can be changed. This means that the implant can be adapted for each patient, even when the final metal implants have been implanted. For example, if a test of the final prosthesis revealed good internal rotation, but poor external rotation, then the liner can be ‘dialled’ to achieve more equal rotations.

An independent biomechanical study from Imperial College London compared six different RTSA glenoid components with micromotion set to 50 μm [45]. The six implants were the Verso, the Delta III (DePuy), the Anatomical (Zimmer), the Bayley-Walker (Stanmore), the RSP-reduced (Encore) and the RSP-neutral (Encore). Stability is required to encourage bone ingrowth and long-term survival of the implant. They found that the Verso was the most stable implant. Peak micromotion at the implant-bone interface was lowest for the Verso.

../images/429740_1_En_12_Chapter/429740_1_En_12_Figb_HTML.png — Peak micromotion seen in six different RTSA implants (Reproduced from original article by Hopkins and Hansen [45])

A series of 102 patients treated with the stemless Verso RTSA reported by Levy et al. [18] achieved good outcomes. Indications for surgery included 65 cases of cuff tear arthropathy, 13 cases of rheumatoid arthritis and 12 fracture sequelae. Seventeen cases were revisions. No patients were excluded on grounds of poor bone quality. All patients had a minimum follow-up of 2 years (range 2–7 years). Constant score improved from 14 preoperatively to 59 (age and sex adjusted 86) postoperatively. Mean postoperative movements were 129° of forward flexion, 51° of external rotation and 65° of internal rotation. This unusually good rotation may reflect the ability to ‘dial’ the liner. At the last follow-up, 96.9% of patients reported either no pain or mild pain. Patient satisfaction (subjective shoulder value) improved from 8, to 85 out of 100. Surgical complications were two cracks of the metaphysis and one crack of the glenoid rim during implantation. All three healed without further treatment, achieving good final Constant scores. Two early postoperative dislocations occurred. One patient dislocated by extending his shoulder and pushing himself out of a chair 1 week after surgery, and one patient had an osteophyte which hinged the liner to dislocate. Both were reoperated and recovered well, achieving good outcomes. There was also one disengagement of the glenoid head from the baseplate which was caused intraoperatively by unnoticed soft tissue interposition between the baseplate and the glenosphere. After removal of the interposed tissue, the patient made a good recovery. Other postoperative complications were two acromial fractures and six late traumatic periprosthetic fractures. The metaphyseal periprosthetic fractures healed well without requiring surgery. One late fracture involving the diaphysis was revised to a stemmed Verso prosthesis. Glenoid notching was present in 21 patients: 18 grade I–II notching and 3 grade III. There were no signs of lucency, subsidence or stress shielding during the 2–7-year follow-up period. The authors concluded that this stemless metaphyseal design provided encouraging short to mid-term results associated with excellent pain relief and function, restoration of movement and high levels of patient satisfaction.

Atoun et al. [31] reported a series of 31 patients treated with the Verso stemless RTSA and followed up for a mean of 36 months (range 24–52 months). Outcome assessments were performed by an independent observer. Constant score improved significantly from 12.7 preoperatively to 56.2 postoperatively (age and sex adjusted 80.2). Similarly, satisfaction improved from 2.4/10 to 8.5/10. Mean postoperative range of movement was 128.5° of forward flexion, 116.5° of abduction, 50.8° of external rotation and 64.6° of internal rotation. Two early dislocations required further surgery, one for re-orientation of the liner and one for resection of an inferior osteophyte. There were two cases of grade I–II notching. No loosening, radiographic lucencies or subsidence occurred. Surgical complications were three minor intraoperative cracks which did not require treatment, did not affect the operation and healed without affecting the results. Two cracks occurred in the humeral metaphysis and one in the glenoid. These cracks were considered by the authors to represent part of their learning curve. Five late periprosthetic fractures were sustained after falls. Four of these healed without surgery and resulted in good outcomes. One fracture involving the diaphysis was revised to a stemmed implant. The authors concluded that the clinical and radiographic results of this bone-preserving metaphyseal RTSA implant were encouraging.

Levy et al. [43] also reported a series of 19 patients who received staged bilateral stemless Verso RTSA. Some studies have reported reduced active rotational movement following RTSA [46–48]. Good rotation is essential for activities of daily living (ADL) such as perineal and self-hygiene, eating, drinking and combing hair [49]. This paper aimed to assess whether patients with bilateral stemless RTSA were compromised in ADL, with particular regard to lack of rotation. Mean follow-up was 48 months (range 24–75 months). Constant score improved from 18.7 preoperatively to 65.1 postoperatively. Internal rotation improved from 9° to 81°, and external rotation improved from 20° to 32° with the arm in adduction by the side of the body. Thirty-one shoulders had full external rotation in elevation. Mean postoperative patient-reported ADLEIR (Activities of Daily Living External and Internal Rotations) score was 33 out of 36 points. The authors concluded that bilateral stemless RTSA provided predictably good functional outcomes, including rotations, and that most patients had no postoperative limitation in ADL or leisure activities.

12.2.2 TESS—Total Evolutive Shoulder System (Biomet, Warsaw, IN, USA)

The TESS reverse was introduced in France in 2005. The system has both a stemmed and a stemless metaphyseal fixed humeral implant. The stemless humeral implant is a cup made from cobalt-chrome. The implant has a titanium plasma spray and a hydroxyapatite coating for bone ingrowth. The cup is impacted into the humeral metaphysis and is designed for use with a humeral cut of 150°. There are six anti-rotation wings on the undersurface of the humeral implant. A polyethylene liner clips into the cup and is held in place by a metal ring. The glenoid baseplate is fixed with four screws. The glenosphere is also made of cobalt-chrome and screws onto the glenoid baseplate.

../images/429740_1_En_12_Chapter/429740_1_En_12_Figc_HTML.png — The humeral component of the TESS RTSA and X-rays of the TESS in situ (Reproduced with kind permission of Elsevier)

Tiessier et al. [50] performed 91 TESS stemless RTSA for patients with cuff tear arthropathy or massive cuff tears. All patients had a minimum follow-up of 2 years. Mean follow-up was 41 months (range 24–69 months). Constant score improved from 40 to 68. Mean postoperative forward flexion was 143° and external rotation was 39°. No loosening occurred. However, the authors did not report on the presence or absence of subsidence or lucencies. Nineteen per cent of cases had grade I–II notching. No intraoperative complications occurred. Postoperative complications were one stress fracture of the scapular spine, one fall resulting in a traumatic clavicle fracture and one case of recurrent dislocation requiring revision to a larger polyethylene spacer. Overall, 96% of patients rated their satisfaction as good or excellent. The authors concluded that stemless TESS RTSA is reliable, less invasive than stemmed implants and produces favourable mid-term outcomes with a low rate of complications.

Ballas and Beguin [51] reported 56 patients treated with the TESS RTSA. Most patients had cuff tear arthropathy or massive cuff tears. Mean follow-up was 58 months (range 38–95 months). Constant score improved from 29 to 62, and Oxford Shoulder Score improved from 46 to 17. Range of movement also improved, achieving a mean postoperative forward flexion of 140° and external rotation of 45°. There were no cases of subsidence or implant loosening. One patient had osteolysis of the greater tuberosity. Five patients had stage I notching which appeared at 1 year postoperatively and were non-progressive at the last follow-up. One partial intraoperative crack of the metaphysis occurred but did not require any treatment. Other postoperative complications were one superficial infection, one subscapularis tendon rupture, one stress fracture of the acromion and one haematoma evacuation. Three patients were subsequently revised to a stemmed reverse prosthesis. The authors reported that at revision, the primary stemless implants were easily removable, without damage to the remaining bone stock, and allowed implantation of a stemmed implant in the same orientation as a primary stemmed reverse arthroplasty. They concluded that at almost 5 years of follow-up, stemless RTSA clinical and radiological outcome results were comparable to stemmed implants, whilst avoiding the problems associated with a stem.

Moroder et al. [15] compared 24 patients treated with stemless TESS RTSA with 24 matched patients who received stemmed RTSA with the DELTA XTEND (DePuy Synthes, Warsaw, IN, USA). Patients were matched for age, sex and length of follow-up. All patients had a diagnosis of cuff tear arthropathy. Stemless implants were chosen for patients with an intact cortical ring after osteotomy, no visible cysts at the osteotomy site and when the trabeculae at the osteotomy site were judged to produce sufficient resistance to pressure applied by the surgeon’s thumb. After a mean follow-up of 35 months (range 24–75 months), there were no differences in Constant score, pain, satisfaction, strength or range of movement. There was a trend towards better internal rotation in the stemless group. Complications in the stemless group were one traumatic dislocation after a fall downstairs, one acromial fracture which did not require treatment and two cases of grade I notching. In the stemmed group, there were five cases of grade I notching and four cases of grade II notching. This increased notching with the stemmed implant is likely to reflect the shallower inclination angle of the humeral implant in the stemmed group (155° rather than 135° for the stemless TESS). The stemmed group also had two patients requiring postoperative blood transfusion and two postoperative wound haematomas. No transfusions or haematomas occurred in the stemless group. Other stemmed complications were one transient paraesthesia and one case of inlay snapping which was treated with inlay exchange. Surgical time in the stemless group was significantly shorter, at 80.5 min compared to 109.5 min for stemmed implants. No loosening occurred in either group. Two stemless implants had signs of lucency on postoperative X-rays. However, lucencies were more common in the stemmed group, with 29% of stemmed implants affected. All stemmed implant lucencies were in the metaphysis and hence likely to represent stress shielding. The authors concluded that at short- to medium-term follow-up, stemless TESS RTSA implants were not inferior to traditional stemmed implants in patients with good bone quality. Only 18.4% of their patients were deemed to have sufficient bone quality for the TESS stemless RTSA. Consequently, more than 80% of their patients still had to be treated with a stemmed implant.

Von Engelhardt et al. [52] reported a series of 67 TESS RTSA, including 56 stemless implants. Mean follow-up was 17.5 months. Overall, normalized Constant score improved from 11.3 to 78.8. One stemmed patient had loosening of the humeral implant. Conversely, no patients in the stemless group developed loosening. They concluded that stemless implants were able to achieve good clinical outcomes.

Kadum et al. [53] also reported a series of 40 TESS RTSA, including 16 stemless implants. Follow-up ranged from 15 to 66 months. Both stemmed and stemless implants produced improved functional outcomes, improved quality of life and reduced pain. QuickDASH improved from 67 to 29 in stemless cases and from 56 to 35 in stemmed cases. Postoperative forward flexion and abduction were both 110° in the stemless group, compared to 90° in the stemmed group. One stemmed patient developed resorption of the proximal humerus. In contrast, no humeral loosening occurred in the stemless group. However, 2 of the 16 stemless implants were revised within the first postoperative week for corolla displacement. This complication would appear to be implant specific, and it is possible that greater experience and familiarity with the implant might help to avoid this scenario. Overall, the authors concluded that RTSA with a stemless TESS implant is reliable if bone quality is adequate.

12.2.3 Nano

The Nano (Biomet, Warsaw, IN, USA) was launched in Europe in 2012. It is the second generation of stemless implants from Biomet. Its design was based on the TESS stemless prosthesis. The Nano is a stemless convertible platform system which can be used in both anatomic and reverse configurations. The humeral implant is impacted into metaphyseal bone. The Nano has a female Morse taper which locks into the male Morse taper on the head implant. A literature search did not reveal any published case series using the Nano prosthesis. There is a single case report by Giannotti et al. [54] who used the reverse configuration of the Nano to treat a 65-year-old woman with Parkinson’s disease and cuff tear arthropathy. At 3 months of follow-up, her X-ray showed a well-positioned prosthesis, and she reported reduced pain. However, in 2014 a safety alert warning was issued by Biomet, reporting that the Nano should not be used in cases of poor bone quality or bone cysts [55].