Inherent disadvantages of reverse shoulder arthroplasty designs based on the Grammont concept have raised a renewed interest in less-medialised designs and techniques. The aim of this study was to evaluate the outcome of reverse shoulder arthroplasty (RSA) with the fully-constrained, less-medialised, Bayley–Walker prosthesis performed for the treatment of rotator-cuff-deficient shoulders with glenohumeral arthritis. A total of 97 arthroplasties in 92 patients (53 women and 44 men, mean age 67 years (standard deviation (sd) 10, (49 to 85)) were retrospectively reviewed at a mean follow-up of 50 months ((sd 25) (24 to 96)). The mean Oxford shoulder score and subjective shoulder value improved from 47 (sd 9) and 24 points (sd 18) respectively before surgery to 28 (sd 11) and 61 (sd 24) points after surgery (p <  0.001). The mean pain at rest decreased from 5.3 (sd 2.8) to 1.5 (sd 2.3) (p < 0.001). The mean active forward elevation and external rotation increased from 42^°(sd 30) and 9^° (sd 15) respectively pre-operatively to 78^° (sd 39) and 24^° (sd 17) post-operatively (p < 0.001). A total of 20 patients required further surgery for complications; 13 required revision of components. No patient developed scapular notching.

The Bayley–Walker prosthesis provides reliable pain relief and reasonable functional improvement for patients with symptomatic cuff-deficient shoulders. Compared with other designs of RSA, it offers a modest improvement in forward elevation, but restores external rotation to some extent and prevents scapular notching. A longer follow-up is required to assess the survival of the prosthesis and the clinical performance over time.

Cite this article: Bone Joint J 2014;96-B:936–42.

Reverse polarity total shoulder arthroplasty (RTSA) has gained popularity over recent years for the treatment of the painful cuff deficient shoulder. Although proposed over 20 years ago and despite good clinical outcomes the RTSA has struggled to gain popularity due to reported high levels of complications. One such complication is post-operative instability with frequencies of up to 30% (De Wilde 2002). The Bayley-Walker RTSA was designed specifically for patients with difficult reconstruction problems in whom an unconstrained prosthesis would not offer sufficient stability. It is a reverse anatomy fixed fulcrum constrained prosthesis. The glenoid component has a long HA-coated tapered helical screw, with large pitch and depth, fixation is augmented by a grooved HA coated glenoid plate. The purpose of this study was to review the clinical experience from The Royal National Orthopaedic Hospital Stanmore and to ascertain the rate of glenoid component loosening. We also carried out a radiographic review to correlate loosening with patterns of lucency on post-operative radiographs. One hundred and five B-W TSRs in 103 patients were included, 24% of which were performed as revision of previous failed arthroplasty. In total, 8/105 glenoids required revision. Of those eight patients, two were cases of septic loosening. Of all nine specified areas of glenoid, tip lucency on x-ray appeared to be most strongly associated with need for glenoid revision. 5/9 cases with tip lucency progressed to loosening of the glenoid. Where tip lucency was not seen, 93/96 glenoid components remained secure, giving tip lucency a negative predictive value of 97%. Excluding the two infected cases, the glenoid remained secure in 97/103 patients undergoing BW-TSR with follow-up up to 13 years. The BW-TSR is a satisfactory and durable solution to the cuff-deficient shoulder in variety of challenging groups including younger patients and as a salvage procedure following failed, cuff-deficient arthroplasty

Between 1997 and 2007, 68 consecutive patients underwent replacement of the proximal humerus for tumour using a fixed-fulcrum massive endoprosthesis. Their mean age was 46 years (7 to 87). Ten patients were lost to follow-up and 16 patients died. The 42 surviving patients were assessed using the Musculoskeletal Tumor Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS) at a mean follow-up of five years and 11 months (one year to ten years and nine months). The mean MSTS score was 72.3% (53.3% to 100%) and the mean TESS was 77.2% (58.6% to 100%).

Four of 42 patients received a new constrained humeral liner to reduce the risk of dislocation. This subgroup had a mean MSTS score of 77.7% and a mean TESS of 80.0%. The dislocation rate for the original prosthesis was 25.9; none of the patients with the new liner had a dislocation at a mean of 14.5 months (12 to 18).

Endoprosthetic replacement for tumours of the proximal humerus using this prosthesis is a reliable operation yielding good results without the documented problems of unconstrained prostheses. The performance of this prosthesis is expected to improve further with a new constrained humeral liner, which reduces the risk of dislocation.

We retrospectively studied 67 patients who underwent proximal humeral replacement with the Bayley-Walker prosthesis, for tumour of the proximal humerus between 1997 and 2007. Of the 67 patients 10 were lost to follow up. Of the 41 surviving patients, function was assessed using the Musculoskeletal Tumour Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS) questionnaire. 4 of the 41 patients received the new Bayley-Walker ‘captured’ proximal humeral replacement. The mean age was 46 years (7–87). The mean MSTS score at follow-up was 72.0 % and the mean TESS score was 77.2 %. The sub-group of 4 pts who received the new captured prosthesis had a mean MSTS score of 77.7 %. There was no mechanical failure of any prostheses in the follow up period. Endoprosthetic replacement for tumour of the proximal humerus with the Bayley-Walker prosthesis, is a reliable operation yielding reasonable functional results and good long-term prosthesis survivorship. The performance of this prosthesis is expected to improve further with the new ‘captured’ prosthesis

Wear of polyethylene is associated with aseptic loosening of orthopaedic implants and has been observed in hip and knee prostheses and anatomical implants for the shoulder. The reversed shoulder prostheses have not been assessed as yet. We investigated the volumetric polyethylene wear of the reversed and anatomical Aequalis shoulder prostheses using a mathematical musculoskeletal model. Movement and joint stability were achieved by EMG-controlled activation of the muscles. A non-constant wear factor was considered. Simulated activities of daily living were estimated from in vivo recorded data.

After one year of use, the volumetric wear was 8.4 mm³ for the anatomical prosthesis, but 44.6 mm³ for the reversed version. For the anatomical prosthesis the predictions for contact pressure and wear were consistent with biomechanical and clinical data. The abrasive wear of the polyethylene in reversed prostheses should not be underestimated, and further analysis, both experimental and clinical, is required.

The restoration of pain-free stable function in gleno-humeral arthritic cases in various situations such as rotator cuff deficiency, old trauma and failed total shoulder arthroplasty is a challenging clinical dilemma. The Bayley-Walker shoulder has been designed specifically for very difficult cases where surface replacement devices do not provide sufficient stability. This device is a fixed-fulcrum reversed anatomy prosthesis consisting of a titanium glenoid component with a CoCrMo alloy head that articulates with an UHMWPE liner encased in a titanium alloy humeral component that has a long tapered grooved stem. The centre of rotation of the Bayley-Walker shoulder is placed medially and distally with respect to the normal shoulder in order to improve the efficiency of the abductor muscles. An important problem in devices of this type is obtaining secure and long-lasting fixation of the glenoid component. The glenoid component relies on fixation through the cortical bone by using threads, which protrude through the anterior surface of the scapula at the vault of the glenoid. It is HA coated for subsequent osseointegration. The purpose of this study was to investigate fixation of the glenoid component. A 3D finite element model of the glenoid component implanted in a scapula was analysed using Abaqus. The implant was placed in position in the scapula, with the final 2–3 screw threads cutting through the cortical bone on the anterior side at the vault of the glenoid due to the anatomy in this region. The analysis was performed for two load cases at 60° and 90° abduction. A histological study of a retrieval case, obtained 121 days after implantation, was also conducted. The FEA results showed that most of the forces were transmitted from the component to the cortical bone of the scapula, the remaining load being transmitted through cancellous bone. In particular the area where the threads of the glenoid component penetrated the scapula showed high strain energy densities. Histology from the retrieved case showed evidence of bone remodelling whereby new bone growth resulting in cortical remodelling had occurred around the threads. Both the FEA and histological study show that fixing the component at multiple locations in cortical bone may overcome the problems of glenoid loosening associated with constrained devices. The Bayley-Walker device has been used on a custom basis since 1994; 81 Bayley–Walker shoulders for non-tumour conditions and 43 Bayley-Walker glenoid components have been used in association with a bone tumour implant, with good early results. Radiographically, radiolucencies have not been observed and overall the comparisons with the original Kessel design are positive

The aim of the study was to analyze the results of the Bayley-Walker Fixed Fulcrum Total Shoulder Replacement done at our institution. We present a retrospective study of 13 Bayley-Walker Total Shoulder Replacement (BWTSR) with a short follow-up of three to 38 months. Indications for the surgery included severe pain, and all the patients had a dysfunctional rotator cuff not considered to be amenable to surgical repair. Five patients had had previous failed rotator cuff repairs. One patient had a shoulder dislocation following a rotator cuff repair. Not all patients had glenohumeral arthritis. Five males and eight females were treated with BWTSR with a mean age of 66.5 years. Eight patients had left sided BWTSR and five patients had right shoulders replaced. A McKenzie approach was most commonly employed. Post-operatively in most cases early assisted active mobilisation was encouraged. The Oxford shoulder assessment questionnaire was used in the postoperative subjective assessment. Constant functional assessment score improved on average from 24.3 preoperative to 64.5 postoperative. Complications include significant glenoid fracture during surgery in three patients. One patient had significant infection which responded to treatment, the joint survived and the patient has a good result. One patient had dislocation of the UHDPE liner due to faulty technique. We conclude that BWTSR is a reliable procedure in a painful rotator cuff deficient shoulder. In suitable patients better results can be achieved than with non-constrained prostheses. The worst results of BWTSR are comparable to the poor results of unconstrained replacement