Validation of a new classification for periprosthetic shoulder fractures

The Treatment of Periprosthetic Fracture Revision of the Humerus with "Bamboo Support" Structural Allograft Technique-Atrophic Non-Union of a Post-Operative Periprosthetic Fracture after Reverse Total Shoulder Arthroplasty: A Case Report

Periprosthetic fractures are a serious complication of joint replacement surgery. With the growing prevalence of reverse total shoulder arthroplasty (RTSA), the incidence of relatively uncommon periprosthetic humeral fractures has increased. Here, we present the unique case of a 74-year-old woman who developed atrophic non-union after plate osteosynthesis for a periprosthetic fracture associated with RTSA. Fixation failure was evident 3 months after the surgical intervention; the patient underwent a 3-month course of arm sling immobilization. However, bone resorption continued, and varus angulation of the fracture developed. In this case, surgical strategy involved the use of long proximal humerus internal locked system plate (DePuy Synthes, Paoli, PA, USA), augmented with autologous iliac bone graft and allogenic humerus structural bone graft with the "bamboo support technique", fixed with Cable System (DePuy Synthes, Paoli, PA, USA). No reports have addressed the management of failed periprosthetic fractures using allogeneic humeral strut bone grafts. This report aims to fill the gap by presenting a novel surgical technique for the management of periprosthetic fractures associated with RTSA in case of treatment failure.

Non-operative management of humeral periprosthetic fracture after stemless shoulder arthroplasty

PURPOSE

Periprosthetic fractures around a stemless implant often involve lesser and greater tuberosities with a well-fixed implant in the metaphysis. This exposes the surgeon to unique questions and challenges as no surgical option (open reduction and internal fixation or revision to a stem) appears satisfactory to address them. Purpose of this study was to evaluate the clinical outcomes after non-operative management of periprosthetic fractures after stemless shoulder arthroplasty.

METHODS

A retrospective multicenter study was conducted to identify all patients who had sustained non-operative management of a periprosthetic fracture after a stemless shoulder. Exclusion criteria were as follows: (1) intraoperative fractures and (2) implant loosening. Primary outcomes included mean Constant score and mean active range of motion. Secondary outcomes were VAS, radiological analysis, and complications.

RESULTS

Nine patients were included. One was excluded due to the loss of follow-up at three months. Mean age was 79 years. At the last follow-up, no significant difference was observed between the Constant score, VAS, or the range of motion before fracture and at the last follow-up. Fracture healing did not result in any change in angulation in the frontal plane in seven cases and was responsible for a varus malunion in two cases of anatomic arthroplasty. No change in lateralization or distalization was reported. No cases of implant loosening after fracture have been observed.

CONCLUSIONS

Conservative management seems to be appropriate in cases of minimally displaced fractures without implant loosening.

Incidence of complications related to shoulder arthroplasties identified on computed tomography

PURPOSE

Determine incidence of shoulder arthroplasty complications identified on computed tomography (CT).

MATERIALS AND METHODS

Retrospective institutional database review of patients with shoulder arthroplasties who underwent CT between 01/2006-11/2021 at a tertiary academic referral center with subspecialized orthopedic shoulder surgeons. CT reports were reviewed for arthroplasty type and complication. Data were stratified and summarized. Associations between complications and arthroplasty types were determined with Chi-squared goodness of fit test.

RESULTS

Eight hundred twelve CTs in 797 unique patients were included (438 (53.9%) females and 374 (46.1%) males; mean age 67 ± 11 years). There were 403 total shoulder arthroplasties (TSA), 317 reverse total shoulder arthroplasties (rTSA), and 92 hemiarthroplasties (HA). Complications were present in 527/812 (64.9%) and incidences were: loosening/aseptic osteolysis 36.9%, periprosthetic failure 21.6%, periprosthetic fracture 12.3%, periprosthetic dislocation 6.8%, joint/pseudocapsule effusion 5.9%, prosthetic failure 4.8%, infection 3.8%, and periprosthetic collection 2.1%. Complications per arthroplasty were: 305/403 (75.7%) TSAs, 176/317 (55.5%) rTSAs, and 46/92 (50%) HAs (p < 0.001). Periprosthetic fracture (20.8%), prosthetic dislocation (9.8%), and prosthetic failure (7.9%) were highest in rTSAs (p < 0.001, p < 0.013, p < 0.001, respectively). Loosening/aseptic osteolysis most frequent in TSAs (54.1%) (p < 0.001). Periprosthetic failure most frequent in HA (32.6%) (p < 0.001). Significant associations were identified with joint/pseudocapsule effusion and loosening/aseptic osteolysis (p = 0.04) and prosthetic dislocation (p < .001).

CONCLUSION

In this single tertiary academic referral center cohort, the incidence of shoulder arthroplasty complication identified on CT was 64.9% and the most commonly occurring complication was loosening/aseptic osteolysis (36.9%). TSA had the highest incidence of complication (75.7%).

Inter-Observer and Intra-Observer Reliability Assessment of the Established Classification Systems for Periprosthetic Shoulder Fractures

This study evaluated the reliability and comprehensiveness of the Unified classification system (UCPF), Wright & Cofield, Worland and Kirchhoff classifications and related treatment recommendations for periprosthetic shoulder fractures (PPSFx). Two shoulder arthroplasty specialists (experts) and two orthopaedic residents (non-experts) assessed 20 humeral-sided and five scapula-sided cases of PPSFx. We used the unweighted Cohen's Kappa (κ) for measuring the intra-observer reliability and Krippendorff's alpha (α) for measuring the inter-observer reliability. The inter-rater reliabilities for the Wright & Cofield and Worland classifications were substantial for all groups. The expert and non-expert groups for UCPF also showed substantial inter-rater agreement. The all-rater group for the UCPF and the expert and non-expert group for the Kirchhoff classification revealed moderate inter-rater reliability. For the Kirchhoff classification, only fair inter-rater reliability was found for the non-expert group. Almost perfect intra-rater reliability was measured for all groups of the Wright & Cofield classification and the all-rater and expert groups of the UCPF. All groups of the Kirchhoff and Worland classifications and the group of non-experts for the UCPF had substantial intra-rater reliabilities. Regarding treatment recommendations, substantial inter-rater and moderate intra-rater reliabilities were found. Simple classification systems for PPSFx (Wright & Cofield, Worland) show the highest inter- and intra-observer reliability but lack comprehensiveness as they fail to describe scapula-sided fractures. The complex Kirchhoff classification shows limited reliability. The UCPF seems to offer an acceptable combination of comprehensiveness and reliability.

Evaluation and treatment of postoperative periprosthetic humeral fragility fractures

Postoperative periprosthetic humeral shaft fractures represent a growing and difficult complication to treat given the aging patient population and associated bone loss. Determining the best treatment option is multifactorial, including patient characteristics, fracture pattern, remaining bone stock, and implant stability. Possible treatment options include nonoperative management with bracing or surgical intervention. Nonoperative treatment has been shown to have higher nonunion rates, thus should only be selected for a specific patient population with minimally displaced fractures or those that are unfit for surgery. Surgical management is recommended with prosthetic loosening, fracture nonunion, or failure of nonoperative treatment. Surgical options include open reduction and internal fixation, revision arthroplasty, or hybrid fixation. Careful evaluation, decision making, and planning is required in the treatment of these fractures.

Reliability of Current Classification Systems for Periprosthetic Fractures of the Humerus

OBJECTIVE

Numerous classification systems exist to evaluate periprosthetic humerus fractures, although most are based on limited patient numbers. The Wright and Cofield system is the most widely used classification system. We sought to evaluate the interobserver and intraobserver reliabilities of this system compared with the Unified Classification System (UCS) using the largest patient sample to date.

METHODS

This retrospective study identified patients between December 2011 and January 2021 with a periprosthetic fracture of the humerus around the stem of a shoulder arthroplasty component. Three upper extremity fellowship-trained surgeons evaluated all radiographs for stem stability, evidence of preinjury stem loosening, Wright and Cofield classification, UCS classification, and recommended treatment for each case at 2 timepoints separated by 2 months. The kappa statistic for interobserver and intraobserver reliability was calculated.

RESULTS

Seventy-six patients were included. There was moderate interobserver (kappa 0.53) and substantial intraobserver (kappa 0.69) agreement when classifying stem stability after fracture. There was moderate interobserver (kappa 0.48) and intraobserver (kappa 0.60) agreement when evaluating for stem loosening before fracture. There was fair interobserver (kappa 0.29) and moderate intraobserver (kappa 0.51) agreement regarding the UCS class. There was moderate interobserver (kappa 0.41) and intraobserver (kappa 0.57) agreement regarding the proposed treatment. There was slight interobserver (kappa 0.04) and moderate intraobserver (kappa 0.44) agreement regarding the Wright and Cofield classification.

CONCLUSION

The Wright and Cofield system is less reliable than the UCS classification. A more reliable and clinically relevant classification system is needed to standardize discussion of periprosthetic proximal humerus fractures.

Inadvertent, intraoperative, non- to minimally displaced periprosthetic humeral shaft fractures in RTSA do not affect the clinical and radiographic short-term outcome

INTRODUCTION

Little information is available on the clinical and radiographic outcome of intraoperative, non- to minimally displaced humeral fractures that occur during implantation of a stemmed, reverse shoulder prosthesis but are only recognized on routine postoperative radiographs. The goal of this study is to report the clinical and radiographic outcome for this rarely reported fracture type.

MATERIALS AND METHODS

39 conservatively treated non- to minimally displaced intraoperative periprosthetic humeral fractures after stemmed RTSA were detected from our radiographic database between 1.1.2006 and 31.1.2018. Exclusion criteria were lack of patient consent, preoperative humeral fracture, and revision arthroplasties. Clinical (absolute and relative Constant score, the Subjective Shoulder Value) and radiographic (conventional radiographs) assessment was performed preoperatively, at 6 weeks (only radiographically) and at latest follow-up with a minimum follow-up of 2 years.

RESULTS

35 patient's with a mean age of 72 years (range 32-88, SD ± 11 years) and a mean follow-up of 53 months (range 24-124, SD ± 31) were included in the study. At latest follow-up, all clinical outcome parameters except external rotation improved significantly. A complication rate of 17% (n:6) was recorded. At 6 weeks after the index surgery, none of the radiographs showed a fracture displacement or a sintering of the stem. At latest follow-up, all fractures were healed and no stem loosening was observed in any of the shoulders.

CONCLUSIONS

Non- to minimally displaced intraoperative periprosthetic humeral fractures in RTSA have an incidence of about 5% in this series of mainly uncemented press-fit stems. They generally heal without any further treatment and are not associated with stem loosening or compromise the clinical outcome after primary RTSA. Except slight restriction in the postoperative rehabilitation protocol, no further attention or action is needed.

Periprosthetic Postoperative Humeral Fractures After Shoulder Arthroplasty

The increased utilization of shoulder arthroplasty, including revision procedures, combined with rises in life expectancy, is expected to translate into a substantial increase in periprosthetic humeral fractures. The evaluation and management of these fractures needs to be updated to consider fractures that complicate anatomic and reverse arthroplasties and contemporary short-stem and stemless implants. Although conservative treatment is successful in a large proportion of these fractures, several surgical reconstructive techniques are required for the management of all fracture types. Surgical options include internal fixation, graft augmentation, standard revision procedures, and occasionally complex reconstructions including modular segmental prosthesis and allograft prosthetic composites. Most studies on the outcomes of periprosthetic humeral fractures have analyzed small samples and have typically reported on anatomic total shoulders with a standard-length humeral implant. Additional research is required to optimize the management of periprosthetic postoperative humeral fractures in the era of reverse arthroplasty, short stems, and stemless arthroplasty.

Is the Posterior Approach With Posterior locking compression plate and Anterior Allograft Useful and Safe in the Treatment of Periprosthetic Humeral Fractures Following Reverse Total Shoulder Arthroplasty?

Introduction

As the reverse total shoulder arthroplasty (RTSA) surgery has dramatically increased in the last few decades, many complications have followed through. The periprosthetic fracture, at the moment, is still a subject of debate in the orthopedic world. In this monocentric study, along with a literature review of periprosthetic humeral fractures, we would present our institutional experience with the treatment of periprosthetic humeral fractures with a posterior humeral approach, posterior cortex plate fixation, anterior strut allograft, screws, and cerclage wires.

Materials and Methods

Our study consisted in a prospective monocentric study based on 18 patients, with a mean age of 75.3 years (range 64–88), all following a reverse shoulder total arthroplasty (RTSA). Postoperative follow-ups were taken at 1, 6, and 12 months with objective measurement of shoulder motion and strength, while clinical outcome measures were assessed using the American Shoulder and Elbow Surgeons (ASES score) and visual analog scale (VAS) for pain. Together with that, we performed a literature review focused on the management of periprosthetic humeral fractures after shoulder arthroplasty.

Results

All fractures consolidated without complication at a mean 4.2 months (range 3–6). At final follow-up, the average active shoulder flexion was 88° (range 62–129°), active abduction 73° (range 52–91°) and active external rotation 22° (range 3–56°). The average ASES score was 73 (range 59–97), while average VAS score was 1.1 (range 0–3).

Discussion

Surgical treatment of periprosthetic humeral fractures following a shoulder arthroplasty remains a hard challenge for every surgeon, and their treatment must consider fracture’s location, displacement, and local bone quality.

Conclusions

The posterior approach with a posterior plate placement and anterior strut allograft, which is appliable only in case of a B or C type fracture according to Worland classification, could be a good treatment option for periprosthetic humeral fractures.

A Long-Term Follow-Up of Post-Operative Periprosthetic Humeral Fracture in Shoulder Arthroplasty

Background

During the last decades, the growing number of shoulder replacement has increased the associated complications. Periprosthetic fractures have a low incidence but can be a severe clinical condition, especially in elderly population. There are still no guidelines to define the best treatment protocol for post-operative periprosthetic humeral fractures. Factors associated to these fractures and consequently the decision-making for the best treatment seem to be patient-related but also correlated with the type of implant. The aim of this study is to analyze the patient’s risk factors, fracture pattern, implant type and treatment, evaluating the outcome with a long-term follow-up.

Methods

A retrospective study was performed on more than 2700 shoulder prostheses implanted over 10 years in two specialized centers, identifying 19 patients who underwent surgery for post-operative periprosthetic fracture. Gender, age, comorbidities, type of prosthetic implant, type of fracture, and cortical index of each patient were evaluated. All patients underwent surgery and were evaluated with a mean follow-up of 5 years with radiographic controls and functional assessment with the Constant–Murley score.

Results

Complete healing was achieved in 18 of 19 patients. All patients presented a lower Constant–Murley score than the pre-fracture score, there were no significant differences between prosthetic implants, and the cortical index was lower than the threshold level in more than 60% of cases.

Conclusion

The results of this study showed that a correct preoperative planning is essential to evaluate the type of implant and possible signs of stem mobilization. With a stable stem, it is preferable to maintain it and proceed to a synthesis. The decision process is more complex in periprosthetic fractures with a reduced cortical index, when some radiolucency lines are present in stems with high primary stability, because it is not always indicative of an unstable stem.

Level of Evidence

Therapeutic III

Primary stability of fixation methods for periprosthetic fractures of the humerus: a biomechanical investigation

BACKGROUND

The incidence of periprosthetic fractures of the proximal humerus is gradually increasing, following an increase in reverse shoulder arthroplasties in recent years. Locking plate fixation and revision arthroplasty are both valuable treatment methods. However, the primary stability of fixation methods for periprosthetic fractures has not been investigated in detail. The aim of this study was to analyze and compare the primary stability of the common treatment measures.

MATERIALS AND METHODS

Cemented reverse total shoulder arthroplasty (Delta Xtend; DePuy Synthes, Warsaw, IN, USA) was performed in 5 shoulders, and a distal, mid-diaphysis humeral fracture (Wright and Cofield type B) was induced. The implant was left in place, and 3 distinct fixation scenarios were tested: osteosynthesis using 4.5-mm locking plate fixation (subgroup A), 4.5-mm locking plate fixation with an additional 3.5-mm locking plate (subgroup B), and 4.5-mm locking plate fixation with an additional K-wire cerclage (subgroup C). The specimens were tested in a biomechanical setup simulating activities of daily living including rotation. Strain gauges (4-wire strain at 120 Ω; Vishay Measurements Group, Chartres, France) mounted on the 4.5-mm locking plates were used to evaluate the strain of the fixation and to give an estimate of primary stability.

RESULTS

Regarding the simulation of activities of daily living, no statistically significant differences were found in the measured strains on the locking plate between subgroups A, B, and C. A maximum measured strain of 216.85 μm/m in subgroup A resulted in bending of the locking plate (length, 134 mm) of 0.03 mm. In subgroup B (277.01 μm/m), the plate strained 0.04 mm compared with a strain measurement of 0.01 mm in subgroup C (75.93 μm/m).

CONCLUSION

Additional K-wire cerclages or additional 3.5-mm locked plating did not increase primary stability. With a stable prosthetic implant in place, 4.5-mm locked plating is sufficient to address periprosthetic humeral shaft fractures in the present in vitro setup.

Failed Reverse Shoulder Arthroplasty and Recommendations for Revision

PURPOSE OF REVIEW

The most common complications warranting revision consideration in reverse shoulder arthroplasty (RSA) include instability and its associated causes: infection, periprosthetic fracture, and glenoid baseplate loosening. Management of complications can be challenging and the nuances of treatment are still being elucidated. The focus of this paper is to review the treatment of the failed RSA and discuss evidence-based recommendations for revision.

RECENT FINDINGS

The most common complications requiring revision RSA are instability and infection. The causes for instability can be subdivided into three main subcategories: loss of compression, loss of containment, and impingement. Loss of compression is further broken down into 6 subcategories revolving around abnormal prosthesis positioning, undersized prostheses, or intrinsic soft-tissue tension loss leading to instability. Periprosthetic infection can also lead to instability, yet the most appropriate management for infected RSA remains controversial. Restoring stability by maximizing deltoid and soft tissue tension while avoiding impingement revolves around three basic methods: (1) lateralizing and/or upsizing the glenosphere to an inferior position on the glenoid, (2) use of a more constrained polyethylene insert, and (3) distalizing the humerus by increasing the polyethylene thickness and/or the thickness of the humeral tray. Management of periprosthetic joint infection can be performed in one-stage, two-stage, or "three-stage" procedures all showing good outcomes with two-stage procedures being the most commonly performed. However, persistent positive culture with propriobacterium acnes can occur in up to 25% of cases. In order to limit the associated morbidity from failed revision reverse shoulder arthroplasty, continued research on best management of associated complications is warranted.

Post-operative periprosthetic humeral fractures after reverse shoulder arthroplasty: a review of the literature

Background and aim of the work: Post-operative periprosthetic shoulder fractures incidence is gradually raising due to aging of population and increasing of reverse total shoulder arthroplasty (RTSA). Management of this complication represents a challenge for the orthopedic surgeon. Aim of the present study is to critically review the recent literature about epidemiology, risk factors, diagnosis, management and outcome of post-operative periprosthetic humeral fractures occurring on RTSA. Methods: A systematic search of Embase, Medline and Pubmed was performed by two reviewers who selected the eligible papers favoring studies published in the last ten years. Epidemiology, risk factors, diagnostic features, clinical management and outcome of different techniques were all reviewed. Results: 31 studies including reviews, meta-analysis, case reports, clinical and biomechanical studies were selected. Conclusions: Correct clinical management requires adequate diagnosis and evaluation of risk factors. Conservative treatment is rarely indicated. Locking plate fixation and revision arthroplasty are both valuable treatment methods. Surgical technique should be chosen considering age and functional demand, comorbidities, fracture morphology and location, bone quality and stability of the implant. Given the correct indication all surgical treatment can lead to satisfactory clinical and radiographic results despite a relevant complication rate. (www.actabiomedica.it)