Abstract. Aim. Excessive glenoid retroversion and posterior wear leads to technical challenges when performing anatomic shoulder replacement. Various techniques have been described to correct glenoid version, including eccentric reaming, bone graft, posterior augmentation and custom prosthesis. Clinical outcomes and survivorship of a Stemless humeral component with cemented pegged polyethylene glenoid with eccentric reaming to partially correct retroversion are presented. Patients and Methods. Between 2010– 2019, 115 Mathys Affinis Stemless Shoulder Replacements were performed. 50 patients with significant posterior wear and retroversion (Walch type B1, B2, B3 and C) were identified. Measurement of Pre-operative glenoid retroversion and Glenoid component version on a post op axillary view was performed by method as described by Matsen FA. Relative correction was correlated with clinical and radiological outcome. Results. 4 were lost to follow up. 46 patients were therefore reviewed. The mean follow up was 4 years (2–8.9 years). Walch B1, Pre op Retroversion: 12 (8–20), post op retroversion :11.8 (−4 to 19), correction= 0.2. Walch B2, Pre op Retroversion :18.4 (10–32), post op retroversion: 13.2 (1 −22), correction= 5.2. Walch B3, Pre op Retroversion: 19.1 (13–32)post op retroversion : 16.1 (9–25), correction= 3.0. Walch C, Pre op Retroversion: 33.3 (28–42) post op retroversion: 16.0 (6–27), correction= 17.3. 3 patients required revision surgery for rotator cuff failure. Conclusion. Partial correction of glenoid retroversion with eccentric reaming and implantation of cemented pegged polyethylene component leads to satisfactory clinical outcomes at midterm follow up. No revisions for aseptic loosening of the glenoid were required

Introduction. Posterior glenoid wear is common in glenohumeral osteoarthritis. Tightening of the subscapularis causes posterior humeral head subluxation and a posterior load concentration on the glenoid. The reduced contact area causes glenoid wear and potentially posterior instability. To correct posterior wear and restore glenoid version, surgeons may eccentrically ream the anterior glenoid to re-center the humeral head. However, eccentric reaming undermines prosthesis support by removing unworn anterior glenoid bone, compromises cement fixation by increasing the likelihood of peg perforation, and medializes the joint line which has implications on joint stability. To conserve bone and preserve the joint line when correcting glenoid version, manufacturers have developed posterior augment glenoids. This study quantifies the change in rotator cuff muscle length (relative to a nonworn/normal shoulder) resulting from three sizes of posterior glenoid defects using 2 different glenoids/reaming methods: 1) eccentric reaming using a standard (nonaugmented) glenoid and 2) off-axis reaming using an 8, 12, and 16° posterior augment glenoid. Methods. A 3-D computer model was developed in Unigraphics (Siemens, Inc) to simulate internal/external rotation and quantify rotator cuff muscle length when correcting glenoid version in three sizes of posterior glenoid defects using posterior augmented and non-augmented glenoid implants. Each glenoid was implanted in a 3-D digitized scapula and humerus (Pacific Research, Inc); 3 sizes (small, medium, and large) of posterior glenoid defects were created in the scapula by posteriorly shifting the humeral head and medially translating the humeral head into the scapula in 1.5 mm increments. Five muscles were simulated as three lines from origin to insertion except for the subscapularis which was wrapped. After simulated implantation in each size glenoid defect, the humerus was internally/externally rotated from 0 to 40° with the humerus at the side. Muscle lengths were measured as the average length of the three lines simulating each muscle at each degree of rotation and compared to that at the corresponding arm position for the normal shoulder without defect to quantify the percentage change in muscle length for each configuration. Results. As depicted in Figures 1–3, muscle shortening was observed for each muscle for each size defect. For each size uncorrected defect, the subscapularis was observed to wrap around the anterior glenoid rim during internal rotation and with the arm at neutral; both eccentric successfully re-centered the humeral head and eliminate subscapularis wrapping around the anterior glenoid rim. However, eccentric reaming was also found to medialize the joint line and resulted in approximately 1.5, 2.5, and 3.5% additional muscle shortening for each muscle relative to the augmented glenoid in each size defect, respectively. Discussion and Conclusions. This study demonstrates that posterior glenoid wear medializes the joint line and results in rotator cuff muscle shortening. Augmented glenoids offer the potential to better restore the joint line and minimize muscle shortening, particularly when used in large glenoid defects. Future work should investigate the clinical significance of 1.5–3.5% of muscle shortening and evaluate the functional impact of subscapularis wrapping around the anterior glenoid rim

Objective. We aimed to analyse the clinical outcomes and survivorship of anatomic total shoulder arthroplasty using a stemless humeral component with cemented pegged polyethylene glenoid performed with the technique of eccentric reaming to partially correct retroversion. These results were then compared with TSA using the same implant for end-stage shoulder arthritis with a normal version of the native glenoid. Design and methods. A retrospective case series was performed using a prospectively collected database of anatomic TSA patients operated at Woodend General Hospital, Aberdeen, UK. Between 2010 and 2019, 107 total shoulder arthroplasties (TSA) were done using standard anatomic stemless TSA implants (Affinis Short, Mathys Ltd, Bettlach, Switzerland) in 98 patients. Standardized preoperative and postoperative shoulder radiological imaging for glenoid retroversion was collected. Depending on the angle of native glenoid version, patients were divided into retroverted and non-retroverted glenoid as per the Walch Classification. To assess the radiological outcome at the final follow-up, radiolucency was assessed on the glenoid and humeral side using the Lazarus grading. The final clinical and radiologic outcome from the retroverted group was compared with the population with a non-retroverted glenoid. Five TSAs were excluded from the analysis as they did not have satisfactory postoperative radiographs. Hence, a total of 102 shoulders were available for analysis. Results. The mean follow-up was 3.48 years (2-10.2 years) in the retroverted group (n=44) and 3.9 years (2-8.9 years) in the non-retroverted group (n=58). The mean pre-operative retroversion of the glenoid in the retroverted group was 20.18, and the post-operative retroversion was 15.87, with a mean correction of 4.31. There was no significant difference between the two groups in the percentage of radiological loosening. The mean Oxford shoulder score was 41.4 (16-48) in the retroverted group, while it was 42.1 (20-48) in the non-retroverted group. Three patients in the retroverted group required revision surgery for rotator cuff failure. There were no revisions for aseptic loosening or instability. Conclusion. The degree of severity of retroversion of the glenoid was not associated with poor clinical outcomes, revisions, or failure in stemless TSA. At medium-term follow-up, partial correction of retroversion seems to provide comparable outcomes compared to a non-retroverted glenoid

Introduction. Posterior glenoid wear is common with glenohumeral osteoarthritis. To correct posterior wear, surgeons may eccentrically ream the anterior glenoid to restore version. However, eccentric reaming undermines prosthesis support by removing unworn anterior glenoid bone, compromises cement fixation by increasing the likelihood of peg perforation, and medializes the joint line which has implications on joint stability. To conserve bone and preserve the joint line when correcting glenoid version, manufacturers have developed posterior augment glenoids for aTSA and rTSA applications. This clinical study quantifies outcomes achieved using posteriorly augmented aTSA/rTSA glenoid implants in patients with severe posterior glenoid wear at 2 years minimum follow-up. Methods. 47 patients (mean age: 68.7yrs) with 2 years minimum follow-up were treated by 5 fellowship trained orthopaedic surgeons using either 8° posteriorly augmented aTSA/rTSA glenoid components in patients with severe posterior glenoid wear. 24 aTSA patients received posteriorly augmented glenoids (65.8 yrs; 7F/17M) for OA and 23 rTSA patients received posteriorly augmented glenoids (71.8 yrs; 9F/14M) for treatment of CTA and OA. Outcomes were scored using SST, UCLA, ASES, Constant, and SPADI metrics; active abduction, forward flexion, and external rotation were also measured to quantify function. Average follow-up was 27.5 months (aTSA 29.4; rTSA 25.5). A two-tailed, unpaired t-test identified differences (p<0.05) in pre-operative, post-operative, and pre-to-post improvements. Results. A comparison of pre-operative, post-operative, and pre-to-post improvement in outcomes are presented in Tables 1–3, respectively. As described in Table 1, pre-operative outcomes were similar for patients receiving posterior augment aTSA and posterior augment rTSA implants, with only active abduction being significantly less in rTSA patients. Additionally, rTSA patients were noted to be significantly older (p=0.0434) and have significantly longer follow-up (p=0.0358) though no difference was noted in mean patient height, weight, or BMI between cohorts. As described in Table 2, at 2 years minimum follow-up posterior augment aTSA patients were associated with significantly greater SST scores and also had significantly more active abduction and active external rotation than posterior augment rTSA patients. However, as described in Table 3, no significant difference was observed in pre-to-post improvement of outcome scoring metrics and only improvement in active external rotation was observed to be significantly different between the two cohorts. No complications were reported for either posterior augment implant cohort. Conclusions. These results demonstrate positive outcomes can be achieved at 2 years minimum follow-up in patients with severe posterior wear using either posteriorly augmented aTSA/rTSA glenoid implants. While relative differences in outcomes were noted, these mean differences are expected due to differing indications and associated differences in rotator cuff status. Due to the aforementioned concerns of aseptic glenoid loosening in patients with severe posterior glenoid wear, some have recommend treating patients with posterior glenoid wear using only rTSA regardless of the status of the patient's rotator cuff. The results of this study demonstrate that patients with posterior glenoid wear and a functioning rotator cuff can be successfully treated with posterior augmented aTSA as well. Additional and longer-term follow-up is needed to confirm these positive outcomes

Glenohumeral arthritis is associated with eccentric posterior glenoid wear and subsequent retroversion. Total shoulder arthroplasty provides a reliable and robust solution for this pattern of arthritis but success may be tempered by malposition of the glenoid component, resulting in pain, functional impairment, prosthetic loosening and ultimately failure. Correction of glenoid retroversion through anterior eccentric reaming, prior to glenoid component implantation, is performed to restore normal joint biomechanics and maximise implant longevity. The aim of this study was to assess whether magnetic resonance imaging (MRI) or plain axillary radiography (XR) most accurately assessed glenoid version and hence provided the optimal modality for pre-operative templating. Glenoid version was assessed in pre-operative shoulder MRIs and axillary radiographs (XR) by two independent observers in forty-eight consecutive patients undergoing total shoulder arthroplasty. The mean glenoid version measured on magnetic resonance imaging was −14.3 degrees and −21.6 degrees on axillary radiographs (mean difference −7.36, p=<0.001). Glenoid retroversion was overestimated in 73% of XRs. Intra-observer and inter-observer reliability coefficients for MRI were 0.96 and 0.9 respectively. Intra-observer and inter-observer reliability coefficients for XR were 0.8 and 0.71 respectively. Axillary radiographs significantly overestimate glenoid retroversion and are less precise than shoulder magnetic resonance, which provides excellent intra- and inter-observer reliability. MRI is a useful pre-operative osseous imaging modality for total shoulder arthroplasty as it offers a more precise method of determining glenoid version, in addition to the standard assessment rotator cuff integrity

The well-fixed cemented femoral stem and surrounding cement can be challenging to remove. Success requires evaluation of the quality of the cement mantle (interface lucency), position of the stem, extent of cement below the tip of the stem and skill with the specialised instruments and techniques needed to remove the stem and cement without perforating the femur. Smooth surfaced stems can usually be easily removed from the surrounding cement mantle with a variety of stem extractors that attach to the trunnion or an extraction hole on the implant. Roughened stems can be freed from the surrounding cement mantle with osteotomes or a narrow high speed burr and then extracted with the above instruments. Following this, the well-fixed cement mantle needs to be removed. Adequate exposure and visualization of the cement column is essential to remove the well-fixed cement without damage to the bone in the femur. This is important since fixation of a revision femoral component typically requires at least 4 cm of contact with supportive cortical bone, which can be difficult to obtain if the femur is perforated or if the isthmus damaged. Proximally, cement in the metaphyseal region can be thinned with a high speed burr, then split radially and removed piecemeal. It is essential to remember that both osteotomes and high speed burrs will cut thru bone easier than cement and use of these instruments poses a substantial risk of unintended bone removal and perforation of the femur if done improperly. These instruments should, as a result, be used under direct vision. Removal of more distal cement in the femur typically requires use of an extended femoral osteotomy (ETO) to allow for adequate access to the well-fixed cement in the bowed femoral canal. An ETO also facilitates more efficient removal of cement in the proximal femur. The ETO should be carefully planned so that it is distal enough to allow for access to the end of the cement column and still allow for stable fixation of a new implant. Too short of an ETO increases the risk of femoral perforation since the straight cement removal instruments cannot negotiate the bowed femoral canal to access the end of the cement column without risk of perforation. An ETO that is too distal makes cement removal easier, but may not allow for sufficient fixation of a new revision femoral stem. Cement below the level of the ETO cannot be directly visualised and specialised instruments are necessary to safely remove this distal cement. Radiofrequency cement removal devices use high frequency (ultrasonic) radio waves to melt the cement within the canal. Although cement removal with these devices is time consuming and tedious, they do substantially reduce the chances of femoral perforation. These devices can, however, generate considerable heat locally and can result in thermal injury to the bone and surrounding tissues. Once the distal end of the cement mantle is penetrated, backbiting or hooked curettes can be use to remove any remaining cement from within the canal. It is important that all cement be removed from the femur since reamers used for preparation of the distal canal will be deflected by any retained cement, which could result in eccentric reaming and inadvertent perforation of the femur and make fixation of a new implant very challenging. An intra-operative x-ray can be very helpful to insure that all cement has been removed before reaming is initiated. One should always plan for a possible femoral perforation and have cortical strut grafts and a stem available that will safely bypass the end of the cement column and the previous cement restrictor

The well-fixed cemented femoral stem and surrounding cement can be challenging to remove. Success requires evaluation of the quality of the cement mantle (interface lucency), position of the stem, extent of cement below the tip of the stem and skill with the specialised instruments and techniques needed to remove the stem and cement without perforating the femur. Smooth surfaced stems can usually be easily removed from the surrounding cement mantle with a variety of stem extractors that attach to the trunnion or an extraction hole on the implant. Roughened stems can be freed from the surrounding cement mantle with osteotomes or a narrow high speed burr and then extracted with the above instruments. Following this, the well fixed cement mantle needs to be removed. Adequate exposure and visualization of the cement column is essential to remove the well-fixed cement without damage to the bone in the femur. This is important since fixation of a revision femoral component typically requires at least 4cm of contact with supportive cortical bone, which can be difficult to obtain if the femur is perforated or if the isthmus damaged. Proximally, cement in the metaphyseal region can be thinned with a high speed burr, then split radially and removed piecemeal. It is essential to remember that both osteotomes and high speed burrs will cut thru bone easier than cement and use of these instruments poses a substantial risk of unintended bone removal and perforation of the femur if done improperly. These instruments should, as a result, be used under direct vision. Removal of more distal cement in the femur typically requires use of an extended femoral osteotomy (ETO) to allow for adequate access to the well-fixed cement in the bowed femoral canal. An ETO also facilitates more efficient removal of cement in the proximal femur. The ETO should be carefully planned so that it is distal enough to allow for access to the end of the cement column and still allow for stable fixation of a new implant. Too short of an ETO increases the risk of femoral perforation since the straight cement removal instruments cannot negotiate the bowed femoral canal to access the end of the cement column without risk of perforation. An ETO that is too distal makes cement removal easier, but may not allow for sufficient fixation of a new revision femoral stem. Cement below the level of the ETO cannot be directly visualised and specialised instruments are necessary to safely remove this distal cement. Radiofrequency cement removal devices (OSCAR) use high frequency (ultrasonic) radio waves to melt the cement within the canal. Although cement removal with these devices is time consuming and tedious, they do substantially reduce the chances of femoral perforation. These devices can, however, generate considerable heat locally and can result in thermal injury to the bone and surrounding tissues. Once the distal end of the cement mantle is penetrated, backbiting or hooked curettes can be used to remove any remaining cement from within the canal. It is important that all cement be removed from the femur since reamers used for preparation of the distal canal will be deflected by any retained cement, which could result in eccentric reaming and inadvertent perforation of the femur and make fixation of a new implant very challenging. An intraoperative x-ray can be very helpful to insure that all cement has been removed before reaming is initiated