Patient-specific planning in shoulder arthroplasty

Three-dimensional technologies in presurgical planning of bone surgeries: current evidence and future perspectives

BACKGROUND

The recent development of three-dimensional (3D) technologies introduces a novel set of opportunities to the medical field in general, and specifically to surgery. The preoperative phase has proven to be a critical factor in surgical success. Utilization of 3D technologies has the potential to improve preoperative planning and overall surgical outcomes. In this narrative review article, the authors describe existing clinical data pertaining to the current use of 3D printing, virtual reality, and augmented reality in the preoperative phase of bone surgery.

METHODS

The methodology included keyword-based literature search in PubMed and Google Scholar for original articles published between 2014 and 2022. After excluding studies performed in nonbone surgery disciplines, data from 61 studies of five different surgical disciplines were processed to be included in this narrative review.

RESULTS

Among the mentioned technologies, 3D printing is currently the most advanced in terms of clinical use, predominantly creating anatomical models and patient-specific instruments that provide high-quality operative preparation. Virtual reality allows to set a surgical plan and to further simulate the procedure via a 2D screen or head mounted display. Augmented reality is found to be useful for surgical simulation upon 3D printed anatomical models or virtual phantoms.

CONCLUSIONS

Overall, 3D technologies are gradually becoming an integral part of a surgeon's preoperative toolbox, allowing for increased surgical accuracy and reduction of operation time, mainly in complex and unique surgical cases. This may eventually lead to improved surgical outcomes, thereby optimizing the personalized surgical approach.

Stem size prediction in shoulder arthroplasty with preoperative 3D planning

INTRODUCTION

Three-dimensional surgical planning software provides virtual reconstructions of the shoulder with automated joint indices for a preoperative case assessment. The aim of this single center study was to evaluate the concordance between the preoperatively selected humeral components and the final implants used in shoulder arthroplasty.

METHODS

129 cases who had undergone anatomic (n = 16) or reverse shoulder arthroplasty (n = 117) using the same type of uncemented short stem implant and were included for review in this study. The type of arthroplasty, stem size, stem inclination, tray-offset and liner-thickness were noted preoperatively and compared to the final implant specifications used in surgery.

RESULTS

The type of arthroplasty matched the surgical plan in 99.2% of cases, as one case was converted from RSA to TSA. The concordance of planned to implanted stem size was 44.2% and the planned size was in range of one adjacent size in 87.6% of cases. Stem inclination in TSA matched the surgical plan in 50% of cases. Tray offset in RSA was predicted correctly in 65% and liner-thickness matched the surgical plan in 98.3% of cases.

CONCLUSION

Despite a low degree of concordance of planned to implanted stem sizes of 44.2%, the choice of stem size was found to be in range of one adjacent size in 87.6% of cases. Further investigations of other contributing factors are necessary to increase the accuracy of the preoperative selection of humeral implants.

LEVEL OF EVIDENCE

level IV, retrospective case study.

The addition of preoperative three-dimensional analysis alters implant choice in shoulder arthroplasty

BACKGROUND

The primary objective of the present study was to investigate how preoperative imaging modalities including 3D computed tomography (CT) scans with preoperative planning software affect implant choice for shoulder arthroplasty.

METHODS

X-ray, uncorrected 2D CT scans, and 3D CT scans from 21 patients undergoing primary arthroplasty were reviewed by five shoulder surgeons. Each surgeon measured glenoid version, inclination and humeral head subluxation, and then selected an anatomic or reverse shoulder arthroplasty implant based only on these imaging parameters. Each surgeon virtually positioned the implant. Agreement between surgeons and changes in plan for individual surgeons between imaging modalities were assessed.

RESULTS

Average measurements of native version, inclination, and subluxation were similar across all imaging modalities with very good interobserver reliability. Overall, there was a high rate of variability in choice of implant depending on imaging modality. Agreement on implant selection between surgeons improved from 68.6% using x-ray to 80.0% with 3D CT. Introducing age added significant variability, reducing agreement on implant choice to 61.0% with 3D CT.

CONCLUSIONS

The use of preoperative 3D planning changes implant choice in nearly one-third of cases compared to plain radiographs and improves surgeon agreement on implant choice compared to x-ray and 2D CT.Level of evidence: III.

Patient-specific instrumentation improves the reproducibility of preoperative planning for the positioning of baseplate components with reverse total shoulder arthroplasty: a comparative clinical study in 39 patients

BACKGROUND

The application of patient-specific instrumentation (PSI) for reverse total shoulder replacement has been rapidly increasing, which could reduce errors in implant positioning. Although PSI theoretically holds promise, evidence of the accuracy and reliability of PSI in shoulder replacement surgery is limited.

METHODS

Thirty-nine shoulders that underwent reverse total shoulder arthroplasty were included in this study and categorized into two groups: the conventional (n = 20) and PSI (n = 19) groups. Screw (length and angle) and baseplate (version, inclination, translation, and rotation) positioning were calculated based on postoperative computed tomography images using a three-dimensional measurement tool. The difference between the values of the preoperative target and postoperative measurement was calculated to evaluate the reproducibility of preoperative planning. Screw involvement in the suprascapular and spinoglenoid notches was assessed. Thus, the correlation between the position of the baseplate and the screws was assessed.

RESULTS

The mean differences between the planned length and angle (anteroposterior and superoinferior angles) and postoperative measurement in the PSI group were significantly smaller than those in the conventional group. Similarly, the mean difference in baseplate rotation between the planned and postoperative measurements in the PSI group was significantly lower than that in the conventional group (4.5° vs 10.6°; P < .001). The spinoglenoid notch was involved in 10 cases in the conventional group and 2 cases in the PSI group, and this difference was significant (P = .014). Overall, the mean difference between the preoperative and postoperative version, inferior inclination, and rotation values for the baseplate position was significantly correlated with the values for screw position (length and angle).

CONCLUSIONS

PSI improves the reproducibility of preoperative planning for baseplate and screw positioning and reduces the risk of neurovascular injury in reverse total shoulder arthroplasty.

Patient-specific guides in orthopedic surgery

The interest of patient-specific guides (PSGs) lies in reliable intraoperative achievement of preoperative planning goals. They are a form of instrumentation optimizing intraoperative precision and thus improving the safety and reproducibility of surgical procedures. Clinical superiority, however, has not been demonstrated. The various steps from design to implementation leave room for error, which needs to be known and controlled by the surgeon who is responsible for final outcome. Instituting large-scale patient-specific surgery requires management systems for guides and innovative implants which cannot be a simple extension of current practices. We shall approach the present state of knowledge regarding PSGs via 5 questions: (1) What is a PSG? Single-use instrumentation produced after preoperative planning, aiming exclusively to optimize procedural exactness. (2) How to use and assess PSGs in orthopedic surgery? Strict rules of use must be adhered to. Any deviation from the predefined objective is, necessarily, an error that must be identified as such. (3) Do PSGs provide greater surgical exactness? The contribution of PSGs varies greatly between procedures. Exactness is enhanced in the spine, in osteotomies around the knee and in bone-tumor surgery. In the shoulder, their contribution is seen only in complex cases. Data are sparse for hip replacement, and controversial for knee replacement. (4) What are the expected benefits of PSGs? As well as improving exactness, PSGs allow a lower radiation dose and shorter operating time. They also enable junior surgeons to train in techniques otherwise reserved to hyperspecialists. (5) How to include PSGs in everyday practice? As well as their potential clinical interest, PSGs involve deep changes in organization, equipment provision and economic model. LEVEL OF EVIDENCE: V; expert opinion.

Midterm clinical and radiologic survivorship of a stemless total shoulder arthroplasty

AIM

The aim of this study was to evaluate the clinical and radiologic outcomes of stemless total shoulder arthroplasty (TSA) in patients with glenohumeral arthritis.

PATIENTS AND METHODS

This is a retrospective case series of all patients who underwent a TSA with Affinis Short prosthesis during the period 2010-2017. Seventy-two TSAs were performed within our unit, in 62 patients (45 females and 17 males), with 10 patients having bilateral TSAs with this prosthesis. The mean follow-up was 3.9 years (2-8.7 years). Patients were evaluated clinically with the Oxford Shoulder Score, range of movement assessment, and a numerical patient satisfaction score. Follow-up radiographs were evaluated by 2 reviewers assessing for lucency and assigned a Lazarus grade.

RESULTS

Six patients were lost to follow-up prior to their 2-year review. At last follow-up, the mean forward elevation was 157° (80°-180°), abduction was 150° (60°-180°), and external rotation was 39° (20°-60°). The mode internal rotation was to the lumbar spine, with 95% of patients achieving internal rotation to L5 or higher. The mean Oxford Shoulder Score was 45 (18-48). The mean patient satisfaction score was 4.93/5. No humeral lucencies were observed. Sixty-four percent (n=47) of the glenoids were Lazarus grade 0, showing no evidence of radiolucency. The remaining patients were Lazarus grade 1-3, although none were progressive and all patients were asymptomatic. No patients were revised for aseptic loosening. Four patients underwent revision: 1 for infection, 1 for heterotrophic ossification and stiffness, and 2 for rotator cuff failure.

CONCLUSION

Midterm follow-up results indicate good clinical and radiologic survivorship for this stemless TSA. Our findings suggest good patient function and satisfaction, and no patients have required revision for aseptic loosening. Further follow-up is required to determine long-term survivorship.

Outpatient Shoulder Arthroplasty Patient Selection, Patient Experience, and Cost Analyses: A Systematic Review

BACKGROUND

The utilization of outpatient shoulder arthroplasty has been increasing. With increasing pressure to reduce costs, further underscored by the coronavirus (COVID-19) pandemic, many health-care organizations will move toward outpatient interventions to conserve inpatient resources. Although abundant literature has shown the advantages of outpatient total hip arthroplasty (THA) and total knee arthroplasty (TKA), there is a relative paucity describing outpatient shoulder arthroplasty. Thus, the purpose of this study was to summarize the peer-reviewed literature of outpatient shoulder arthroplasty with particular attention to patient selection, patient outcomes, and cost benefits.

METHODS

The PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Embase databases were queried according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All articles on outpatient shoulder arthroplasty were included. Data on patient selection, patient outcomes, and cost analyses were recorded. Patient outcomes, including complications, reoperations, and readmissions, were analyzed by weighted average.

RESULTS

Twenty-three articles were included for analysis. There were 3 review articles and 20 studies with Level-III or IV evidence as assessed per The Journal of Bone & Joint Surgery Level of Evidence criteria. Patient selection was most often predicated on age <70 years, body mass index (BMI) <35 kg/m2, absence of active cardiopulmonary comorbidities, and presence of home support. Complications and readmissions were not common and either improved or were equivalent to those of inpatient shoulder arthroplasty. Patient satisfaction was high in studies of short-term and intermediate-term follow-up. The proposed cost benefit ranged from $747 to $53,202 with outpatient shoulder arthroplasty.

CONCLUSIONS

The published literature to date supports outpatient shoulder arthroplasty as an effective, safe, and cost-reducing intervention with proper patient selection.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.