Long-term outcomes of radial head arthroplasty for radial head fractures-a systematic review at minimum 8-year follow-up

Isolated MASON type-III radial head fractures: radial head arthroplasty or open reduction and internal fixation - clinical and radiological outcomes with five to fourteen years of follow up

PURPOSE

The aim of this study was to assess functional and radiological outcomes of radial head arthroplasty (RHA) compared to open reduction and internal fixation (ORIF) in isolated Mason type-III fractures with a minimum of five years follow-up.

METHODS

This was a retrospective single-center study of closed isolated Mason type-III radial head fractures operated between January 2008 and December 2017. Nineteen patients were included in group RHA and 35 patients in group ORIF. The mean age was 51 years old in group RHA and 41 years old in group ORIF (p = 0.02). Functional and radiological outcomes were evaluated.

RESULTS

Mean follow up was eight years (range, 5-14). Clinical results and functional scores showed no significant differences, except a better pronation in group RHA (p = 0.04). Two secondary radial head resection or implant removal were performed in each group (p = 0.56) with poor functional outcomes in group ORIF. There was less heterotopic ossification in group RHA (15.8% vs. 42.8%; p = 0.03). Capitulum wear was found in 63% in group RHA against 25.7% in group ORIF (p < 0.05).

CONCLUSION

Functional results of RHA and ORIF were comparable for isolated Mason type-III fractures at a mean follow-up of eight years. We recommend to perform RHA for isolated Mason type-III fracture if articular reduction or stability of the fixation is not satisfying.

LEVEL OF EVIDENCE

III.

A proposal for computed tomography-based algorithm for the management of radial head and neck fractures: the Proximal and Articular Radial fractures Management (PARMa) classification

Background

Owing to the great variety of fracture patterns and limitations of the standard radiographic investigation, all the already available classification systems for radial head and neck fractures (RHNFs) are limited by a poor-to-moderate degree of intraobserver and interobserver reliability. Although computed tomography (CT) is being increasingly used to better understand the fracture characteristics, a CT-based classification system of RHNFs is still lacking. Therefore, in this agreement study, we aimed to propose a classification system based on two-dimensional and three-dimensional (2D/3D) CT to test the hypothesis that this classification has good intraobserver and interobserver reliability. We have also provided a treatment algorithm.

Methods

Our proposed classification-Proximal and Articular Radial fractures Management (PARMa)-is based on 2D/3D CT imaging. It is divided into four types based on different fractures patterns. The 2D/3D scans of 90 RHNFs were evaluated in a blinded fashion by eight orthopedic and one radiology consultant, according to the proposed classification. The first phase of observation aimed to estimate the interobserver agreement. The second phase involved a new observation, 4 weeks after the first analysis, and estimated the intraobserver reliability. The standard radiographs of these 90 fractures were also evaluated by the same observers, with the same timing and methods, based on the same classification. Cohen's Kappa was applied for intraobserver agreement. Fleiss's Kappa was used both within and among the evaluators. Kendall's coefficient of concordance was employed to determine the strength of association among the appraisers' rankings. Furthermore, Krippendorff's alpha was chosen as an adjunctive analysis to assess between evaluators' agreement.

Results

For the intraobserver agreement, Fleiss' Kappa statistics confirmed the consistency (overall kappa values: 0.70-0.82). Cohen's Kappa statistics aligned with Fleiss' Kappa, with similar kappa values and significant P values (P < .001). For interobserver agreement, Fleiss' Kappa statistics for between appraisers showed moderate-to-substantial agreement, with kappa values ranging from 0.54 to 0.82 for different responses. The results relating to the appraisers' observation of standard radiographs showed that the overall Fleiss' Kappa values for intraobserver agreement ranged from 0.34 to 0.82, whereas Fleiss' Kappa statistics for interobserver agreement ranged from 0.40 to 0.69.

Conclusions

The proposed classification system is expected to be reliable, reproducible, and useful for preoperative planning and surgical management. Both 2D and 3D CT allow the identification of the magnitude and position of displacement and articular surface involvement.

Loose-fit vs. press-fit stems and risk for surgical reintervention following radial head arthroplasty: a US-based cohort study of 1575 patients

BACKGROUND

Radial head arthroplasty (RHA) is performed with increasing frequency for reconstruction of comminuted radial head fractures. Implants can be categorized by stem design, either loose fit or press fit. Currently, the RHA literature does not suggest one implant type is superior to another based on revision and reoperation rates, although most RHA outcome studies have small numbers of patients with few events to detect a difference. This study evaluated the association between stem design and risk of revision and reoperation after RHA.

METHODS

A total of 1575 patients aged ≥18 years who underwent primary RHA within a US-based health care system were identified (2009-2021). Revision following the index RHA was the primary outcome of interest; ipsilateral reoperation was a secondary outcome. Multivariable Cox proportional hazard regression was used to evaluate the risk of outcomes by loose vs. press fit with the adjustment for race and ethnicity, American Society of Anesthesiologists classification, region, surgeon RHA volume, and simultaneous ipsilateral extremity procedures.

RESULTS

Of the 1575 RHAs, 681 (43.2%) received a loose-fit stem. The cumulative revision probability was 2.6% for loose fit and 3.5% for press fit. In adjusted analysis, we did not observe a difference in risk of revision (hazard ratio [HR] = 0.78, 95% confidence interval [CI] = 0.41-1.46) or reoperation (HR = 0.73, 95% CI = 0.43-1.25). Additionally, there were no observed differences in risk of revision (HR = 0.62, 95% CI = 0.28-1.38) or reoperation (HR = 0.90, 95% CI = 0.48-1.71) in the patient subgroup who underwent additional procedures in the same extremity at the time of RHA.

CONCLUSION

In this large multicenter cohort of 1575 primary RHAs, we did not observe a difference in risk of revision or reoperation following RHA based on stem design. The choice between using an implant with a loose- or press-fit stem may be based more on surgeon familiarity, implant availability, cost, and ease of use.

Failed radial head arthroplasty treated by removal of the implant

Aims

In patients with a failed radial head arthroplasty (RHA), simple removal of the implant is an option. However, there is little information in the literature about the outcome of this procedure. The aim of this study was to review the mid-term clinical and radiological results, and the rate of complications and removal of the implant, in patients whose initial RHA was undertaken acutely for trauma involving the elbow.

Methods

A total of 11 patients in whom removal of a RHA without reimplantation was undertaken as a revision procedure were reviewed at a mean follow-up of 8.4 years (6 to 11). The range of motion (ROM) and stability of the elbow were recorded. Pain was assessed using a visual analogue scale (VAS). The functional outcome was assessed using the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES), and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). Radiological examination included the assessment of heterotopic ossification (HO), implant loosening, capitellar erosion, overlengthening, and osteoarthritis. Complications and the rate of further surgery were also recorded.

Results

The indications for removal of the implant were stiffness in five patients, aseptic loosening in five, and pain attributed to the RHA in three. The mean time interval between RHA for trauma to removal was ten months (7 to 21). Preoperatively, three patients had overlengthening of the implant, three had capitellar erosion, six had HO, and four had radiological evidence of loosening. At the final follow-up, the mean the flexion-extension arc improved significantly by 38.2° (95% CI 20 to 59; p = 0.002) and the mean arc of prono-supination improved significantly by 20° (95% CI 0 to 72.5; p = 0.035). The mean pain VAS score improved significantly by 3.5 (95% CI 2 to 5.5; p = 0.004). The mean MEPS improved significantly by 27.5 (95% CI 17.5 to 42.5; p = 0.002). The mean OES improved significantly by 9 (95% CI 2.5 to 14; p = 0.012), and the mean DASH score improved significantly by 23.5 (95% CI 7.5 to 31.6; p = 0.012). Ten patients (91%) had HO and osteoarthritis. Two patients underwent further surgery due to stiffness and pain, respectively.

Conclusion

Simple removal of the implant at revision surgery following a failed RHA introduced following trauma provides satisfactory mid-term results with an acceptable risk of complications. Osteoarthritis, instability, and radioulnar impingement were not problems in this series.

Monobloc vs. Modular Radial-Head Arthroplasty for Complex Elbow Trauma: Long-Term Follow-Up and Comparative Evaluation

Introduction: Mason Type 3 radial-head fractures are typically treated with open reduction and internal fixation (ORIF) or radial-head arthroplasty (RHA). Prosthetic options include traditional monobloc implants and newer modular implants designed to match patient anatomy. While short- and medium-term outcomes of metallic RHA are generally favorable, this study aims to compare the long-term outcomes of patients treated with monobloc versus modular implants. Methods: The medical records of all the patients who underwent RHA at a level I trauma center between 2000 and 2011 were retrospectively reviewed. Patients who were available for follow-up were invited for reassessment, which included physical examination, questionnaires for the assessment of elbow pain and function, and follow-up radiographs. Results: Out of 35 patients who had RHA, 13 (37%) had a monobloc prosthesis and 22 (63%) had a modular prosthesis. Out of the patients that could be traced, 4 patients from the monobloc group and 10 patients from the modular group agreed to participate in the study. The mean follow-up time was 15 years in the monobloc group and 12.4 years in the modular group. Patients in the modular group demonstrated superior functional outcomes compared to the monobloc group, with statistically significant improvements in MEPS and DASH scores and a non-significant trend towards better ASES scores and VAS scores. Physical examination revealed a decline in function in the operated arm for both groups, with statistically significant differences favoring the modular group in elbow flexion and extension. Radiographic analysis showed varying degrees of implant loosening, with the modular group exhibiting less loosening compared to the monobloc group. Mild degenerative changes and heterotopic ossification were also observed, predominantly in the modular group. Conclusions: The results suggest that modular implants offer superior functional outcomes compared to monobloc implants. The modular group showed statistically significant improvements in elbow flexion and extension. These findings indicate that modular implants may be a more favorable option for enhancing patient outcomes. Further research with larger sample sizes is recommended to confirm these trends and to better understand the long-term benefits of modular implants.

The impact of anatomic alignment on radiocapitellar pressure following radial head arthroplasty

BACKGROUND

The incidence of radial head fractures is increasing, and radial head arthroplasty (RHA) is being more frequently used as treatment for irreparable fractures. Our objective was to compare radiocapitellar pressure between the native joint and 2 radial head prosthesis conditions: (1) a prosthetic head that was aligned to the forearm axis of rotation and (2) the same prosthesis with an axisymmetric nonaligned head.

METHODS

Ten cadaveric specimens received a pressfit radial head prosthesis (Align; Skeletal Dynamics) for both prosthetic testing conditions. Anatomic alignment (AL) was defined as the prosthetic head aligned to the forearm axis of rotation. Axisymmetric alignment (AX) was defined as the prosthetic radial head aligned to the axis of the prosthetic stem. Axial load was applied with the elbow in extension and the forearm pronated. Data were collected using a Tekscan 4000 sensor.

RESULTS

The mean pressure in the AL and AX groups were significantly higher than the mean pressure in the native joint. Compared with the native joint, the mean pressure was 19% higher in the AL group and 56% higher in the AX group. Peak pressure beyond 5 MPa occurred in 0 specimens in the native joint group, in 1 specimen (10%) in the AL group, and in 5 specimens (50%) in the AX group.

DISCUSSION

Our results demonstrated that a pressfit radial head prosthesis aligned with the forearm axis of rotation yields capitellar pressures that were more similar to the native condition than a nonaligned pressfit prosthesis. These findings suggest that anatomic alignment may optimize capitellar wear properties, improving the long-term durability of radial head arthroplasty.

Outcomes of press-fit radial head arthroplasty in unconstructable radial head fractures with associated elbow injuries: An average 5-year follow up

Aims

Unstable and nonreconstructable radial head fractures require radial head arthroplasty (RHA) to restore stability. Multiple implant designs are available with varying survival rates (76 to 97%). There is concern that loosening of the press-fit stems leads to implant failure. We review our outcomes using the Acumed press-fit prosthesis for trauma.

Methods

Between February 2008 and November 2020, all primary RHA for trauma from a single-centre were reviewed. Primary outcome was implant survivorship. Secondary outcome were clinical, radiographic and patient related outcome measures.

Results

In total, 96 cases were included. Seven revisions were recorded, all within 24-months of implantation. Kaplan-Meier estimated 10-year survival was 92.1% (95% confidence interval (CI) 84.0-96.1%). Median follow-up time was 5.7 years (Interquartile range (IQR) 3.2-8.5 years). Median Oxford Elbow Score was 43 (IQR 29-46) for and median Mayo Elbow Performance Score was 90 (IQR 72-100). 72% were able to fully-return to pre-injury activities. Radiographic analysis identified osteolysis around radial neck (48%), loosening (32%), valgus stem position (20%), heterotopic ossification (16%) and capitellar erosion (15%). No radiological findings were associated with long-term poor clinical outcomes.

Conclusion

Our study demonstrates an excellent survival of press-fit RHA of 92.1% at 10-years. No radiographic features on follow-up were associated with poorer patient recorded outcome measures.

Revision of Failed Radial Head Arthroplasty

BACKGROUND

Revision of radial head arthroplasty (RHA) may be indicated in cases of prosthesis loosening and malposition. Inherent difficulties in revision surgery include poor bone stock and disrupted soft tissue envelope. Although cases of RHA used for revision of failed RHA are rare, there is reasonable expectation for increasing frequency of these cases due to the increasing incidence of primary RHA. Furthermore, there is an increasing demand for postoperative recovery of function; thus, surgeons may consider revising a failed RHA to a new RHA. We report on series of failed RHA which were revised to a new radial head prosthesis.

METHODS

A retrospective review was performed at multiple institutions for a single radial head prosthesis used for revision of a failed radial head prosthesis. Clinical and radiographic outcomes were collected with a minimum of 1 year of follow-up.

RESULTS

Across 11 patients at a mean follow-up of 45.1 months, the mean Mayo Elbow Performance Score was 81.7; mean Disabilities of the Arm, Shoulder, and Hand scores were 24.4; and mean Visual Analog Scale for pain was 0.6. Radiographic analysis yielded no evidence of capitellar wear or stem loosening.

CONCLUSION

A radial head prosthesis can produce satisfactory results when used for revision of a failed prosthesis. Inherent difficulties in revision surgery include the potential for reduced bone stock and a disrupted soft tissue envelope. Elements of prosthesis design which may contribute to effectively managing revision surgery include a long stem with in-growth surface and prosthetic head alignment to the axis of forearm rotation.

Pyrocarbon radial head arthroplasty offers satisfactory clinical and radiological outcomes with low revision rate: A systematic review

INTRODUCTION

Pyrocarbon promises to be an optimal material choice for radial head arthroplasty (RHA) due to an elastic modulus comparable to the radial diaphysis and thus providing higher biocompatibility. Primary objective was to determine the complications and revision rates related to the usage of these prostheses. The secondary objective was to assess the clinical and radiological outcomes of Pyrocarbon RHAs.

HYPOTHESIS

Pyrocarbon RHAs have good clinical and radiological outcomes with low complications and revisions.

METHODS

Ovid MEDLINE and Embase databases were used to search for studies on outcomes and complications of the RHAs using Pyrocarbon radial head prostheses. The systematic review was designed in accordance with the PRISMA guidelines and included studies were appraised using the MINORS tool. Complications and RHA revision rates were assessed. Functional outcomes were reviewed using PROMs (like MEPI, DASH and BMS), post-op range of motion (using goniometer) and grip strength (using the dynamometer). Postoperative radiological outcomes like peri-prosthetic lucency, radial neck osteolysis, radio-capitellar congruence, capitellar erosion, overstuffing/understuffing and osteoarthritis were reported using radiographs.

RESULTS

A total of 12 studies cumulatively reporting 353 patients who underwent Pyrocarbon RHAs were included in the review. The mean age of patients across the studies ranged from 47 to 54 years of which 50.5% were males. The majority of radial head replacements were done for acute trauma (87.5%) with the remainder done for arthritis (1.7%) and trauma sequelae (10.8%). Mean follow-up period in the selected studies ranged from 18 to 110 months with minimum follow-up across all studies being 12 months. Modular Pyrocarbon (MoPyC, Tornier™) was the implant of choice in ten studies while two studies used the Ascension Pyrocarbon radial head (Ascension Orthopaedics™). Ten studies demonstrated mean MEPI ranging from 75.5 to 96. Mean extension deficit ranged from 6 to 19 degrees, mean flexion from 120 to 140 degrees, mean pronation from 71 to 87 degrees and mean supination from 63 to 85 degrees. Relative grip strength ranged from 69 to 96% of the contralateral limb. Revisions due to implant-related reasons (intra-prosthetic dissociation, prosthetic fracture, peri-prosthetic loosening, radio-capitellar subluxation and understuffed/overstuffed elbow) was 6.8% (24/353). Radial stress shielding and peri-prosthetic lucency was reported in 10 to 100% of patients across different studies but symptomatic implant loosening leading to revision remained rare (2%, 7/353). Radio-capitellar congruence was reported in 81% to 100% cases while capitellar erosion ranged from 0% to 89%. Pyrocarbon implants specific complications included head-neck intra-prosthetic decoupling (1.1%) and pyrocarbon head fractures (0.9%). In total, 5.7% cases underwent re-surgery due to non-RHA related reasons.

DISCUSSION

The pyrocarbon RHA shows good functional outcome, range of motion and low revision rates. This aligns with the working hypothesis of this review. However, pyrocarbon radial head implants have implant-specific complications like pyrocarbon radial head fractures and intra-prosthetic decoupling between stem and head. Despite promising in vitro biomechanical properties, capitellar wear is still a common finding with pyrocarbon RHAs. Despite these factors, pyrocarbon radial head implants are a viable option for radial head arthroplasty.

LEVEL OF EVIDENCE

II; Systematic review.

Open reduction and internal fixation of modified Mason type III/IV radial head fractures with more than three fragments: an analysis of the clinical outcome and reoperation rate

PURPOSE

It is generally accepted that a radial head fracture (RHF) with more than three parts is not suitable for repair; therefore, most authors suggest straightforward radial head arthroplasty (RHA). With up to 20% risk for reoperation after RHA, improvement in reduction and fixation techniques may represent a valuable alternative before further extending the indications for arthroplasty. To determine the functional results and radiological failure rate after osteosynthesis of multi-fragmentary RHF with more than three articular fragments. We specifically determined (1) the one-year Broberg and Morrey functional elbow score, (2) duration of fracture healing, (3) complication rate, and (4) number of patients converted to RHA.

METHODS

This study is a retrospective single-center case series. All patients who underwent primary osteosynthesis for RHF between 2012 and 2019 were included. Nine patients with an average age of 52 years had an average clinical and/or radiological follow-up of 49 months.

RESULTS

The preoperative imaging identified nine fractures with four fragments. Three patients underwent osteosynthesis with plates and screws, whereas six patients underwent osteosynthesis with only screws. The mean Broberg and Morrey score was 95 points. Overall, eight of the nine patients had satisfactory results. All patients retained their radial heads and showed radiological fracture healing. Only two patients presented with low-grade complications requiring no further surgery.

CONCLUSION

Our study showed that osteosynthesis of RHF with up to four fragments can achieve good functional results with a low complication rate and seems to be a valid alternative to RHA.

Radial head replacement for acute complex elbow instability: a long-term comparative cohort study of 2 implant designs

BACKGROUND

Radial head fractures not amenable to reconstruction should be treated by radial head replacement (RHR) when there is associated elbow or forearm instability. There are multiple RHR designs with different philosophies, but 2 of the most commonly used implants include the anatomic press-fit radial head system and the loose-fit metallic spacer. There is little information available specifically comparing the long-term clinical and radiographic outcomes of these 2 systems. The objective of this study was to compare the long-term clinical and radiologic outcomes of 2 RHR designs in the context of complex acute elbow instability.

MATERIALS AND METHODS

Ninety-five patients with an average age of 54 years (range, 21-87 years) underwent an acute RHR (46 press-fit Acumed anatomic and 49 loose-fit Evolve metallic spacer) and were prospectively followed for an average of 61 months (range, 24-157 months). There were 34 terrible triads; 36 isolated RH fractures with medial, lateral, or longitudinal instability; and 25 RH fractures associated with a proximal ulnar fracture. Clinical outcome and disability were evaluated with the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score, and the Disabilities of the Arm, Shoulder, and Hand (DASH) score. Pain and satisfaction were assessed using a visual analog scale. Radiographic analysis included presence of loosening, bone loss, and overstuffing related to the RHR.

RESULTS

Eight patients with an anatomic RHR (2 with overstuffing, 3 for stiffness, and 3 with loose implants) and 1 patient with a spacer (with stiffness) required implant removal. There were no significant differences between spacer RHR and anatomic RHR in arc of motion (120° vs. 113°, P = .14), pain relief (1 vs. 1.7, P = .135), MEPS (94 vs. 88; P = .07), Oxford Elbow Score (42.3 vs. 42.2, P = .4), or DASH score (12.2 vs. 14.4, P = .5). However, patients with a spacer RHR were significantly more satisfied (9 vs. 7.7; P = .004) than those with an anatomic implant. Radiographically, 19 anatomic implants had significant proximal bone loss and 10 showed complete lucent lines around the stem. Lucent lines were common around the spacer RHR. These radiographic changes were not always related to worse clinical outcomes.

CONCLUSION

Both the anatomic and spacer RHR designs can provide good clinical long-term outcomes. However, patients with a spacer showed a higher degree of satisfaction and those with an anatomic press-fit RHR had a higher revision rate, with radiographic changes that warrant continued follow-up.

Mid-term outcome following radial head arthroplasty in acute trauma: risk factors for poor outcome

BACKGROUND

The aims of this study were to evaluate the outcomes of a single type of radial head implant in a large cohort of patients at mid-term follow-up and to determine the associated risk factors for inferior functional outcomes.

METHODS

We performed a retrospective follow-up assessment of 65 patients (33 women and 32 men; mean age, 53.3 years [range, 22-81 years]) who underwent radial head arthroplasty (RHA) for acute trauma between 2012 and 2018, after a minimum follow-up period of 3 years. The Mayo Elbow Performance Score, Oxford Elbow Score, Disabilities of the Arm, Shoulder and Hand score, and Mayo Modified Wrist Score were evaluated, and all available radiographs were analyzed. All complications and revision procedures were assessed. Bivariate and multivariate regression analyses were performed to identify potential risk factors for a poor outcome following RHA.

RESULTS

After an average follow-up period of 4.1 years (range, 3-9.4 years), the mean Mayo Elbow Performance Score was 77.2 (standard deviation [SD], 18.9); mean Oxford Elbow Score, 32.0 (SD, 10.6); mean Mayo Modified Wrist Score, 74.6 (SD, 13.7); and mean Disabilities of the Arm, Shoulder and Hand score, 29.0 (SD, 21.2). Average range of motion measured 10° (SD, 15°) in extension, 125° (SD, 14°) in flexion, 81° (SD, 14°) in pronation, and 63° (SD, 24°) in supination. The overall complication and reoperation rates were 38.5% and 30.8%, respectively, with severe elbow stiffness being the most common reason for revision. Patient age >50 years, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the development of higher-grade osteoarthritis were associated with a poor outcome.

CONCLUSION

Satisfactory medium-term outcomes can be achieved using a monopolar, long-stemmed RHA in patients with acute trauma. However, complication and revision rates are high, frequently leading to inferior outcome scores. Additionally, a higher patient age, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the occurrence of higher-grade osteoarthritis were associated with a poor outcome; these factors should raise awareness by the treating trauma surgeon.

Assessment of progression and clinical relevance of stress-shielding around press-fit radial head arthroplasty

Aims

The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance.

Methods

A total of 97 patients with RHA were analyzed: 56 received a bipolar RHA (Group 1) while 41 received an anatomical implant (Group 2). Radiographs were performed postoperatively and after three, six, nine, and 12 weeks, six, nine, 12, 18, and 24 months, and annually thereafter. PRNR was measured in all radiographs in the four radial neck quadrants. The Mayo Elbow Performance Score (MEPS), the abbreviated version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the patient-assessed American Shoulder and Elbow Surgeons score - Elbow (pASES-E) were used for the clinical assessment. Radiological signs of implant loosening were investigated.

Results

The mean follow-up was six years (2 to 14). PRNR started after a mean of 7.5 weeks (SD 2.1) and progressed significantly during the first two years, by the end of which the bone resorption stabilized. PRNR was detected in 81% (n = 45) of patients in Group 1 and 88% (n = 36) in Group 2. The final mean PRNR was 3.0 mm (SD 2.3) in Group 1 and 3.7 mm (SD 2.5) in Group 2. The mean MEPS, QuickDASH, and pASES-E were 95.9 (SD 11.5), 4.4 (SD 9.2), and 94.8 (SD 10.9) in Group 1 and 92.2 (SD 16.2), 9.9 (SD 21.5), and 90.8 (SD 15) in Group 2, respectively. No significant differences were observed between groups in the clinical and radiological outcomes. No correlations were found between PRNR and the clinical results.

Conclusion

PRNR after press-fit RHA is a common radiological finding that develops in the first 24 months before stabilizing definitively. PRNR does not affect the clinical results or implant survival in the mid term.

In Vivo Assessment of High-Strength and Corrosion-Controlled Magnesium-Based Bone Implants

The biodegradable nature of magnesium in aqueous mediums makes it an attractive material for various biomedical applications when it is not recommended that the material stay permanently in the body. Some of the main challenges that hinder the use of magnesium for bone fracture repair are its limited mechanical strength and fast corrosion rates. To this end, we developed a novel Mg-Zn-Ca-Mn-based alloy and post-fabrication methods that can deliver high-strength and corrosion-controlled implant materials to address these challenges. This study is focused on assessing the in vitro corrosion and in vivo biocompatibility of the developed magnesium-based alloy and post-fabrication processes. The developed heat treatment process resulted in an increase in the microhardness from 71.9 ± 5.4 HV for the as-cast Mg alloy to as high as 98.1 ± 6.5 HV for the heat-treated Mg alloy, and the ceramic coating resulted in a significant reduction in the corrosion rate from 10.37 mm/yr for the uncoated alloy to 0.03 mm/yr after coating. The in vivo assessments showed positive levels of biocompatibility in terms of degradation rates and integration of the implants in a rabbit model. In the rabbit studies, the implants became integrated into the bone defect and showed minimal evidence of an immune response. The results of this study show that it is possible to produce biocompatible Mg-based implants with stronger and more corrosion-controlled properties based on the developed Mg-Zn-Ca-Mn-based alloy and post-fabrication methods.

Clinical Results of Surgical Treatment for Comminuted Radial Head and Neck Fracture: Headless Compression Screws Versus Plate Fixation

Background

We surgically treated comminuted radial head and neck fractures using headless compression screws, including multiple screws for the radial head and a single oblique screw for the radial neck. This study aimed to compare the clinical and radiological results for comminuted radial head and neck fractures between surgery using headless compression screws with a single oblique screw for the radial neck, our new procedure, and a plate system precontoured to the proximal radius.

Methods

This retrospective study included 23 patients (11 and 12 in the screw and plate groups, respectively). The fractures were type 3 according to the Mason-Johnston classification modified by Broberg and Morrey. Clinical outcomes analyzed included the motion range of the elbow and forearm, Mayo Elbow Performance Score, and radiological assessments. In addition, postoperative complications were also investigated. The average follow-up was 18 months.

Results

The bone union was achieved in all the patients, and there were no significant differences in clinical outcomes and radiological assessments except forearm supination (p = 0.02). Furthermore, additional surgical procedures were performed in one and five patients in the screw and plate groups, respectively (p = 0.16). Posterior nerve palsy was observed in two patients in the plate group. Complications were observed in one and six patients in the screw and plate groups, respectively (p = 0.07).

Conclusion

Both surgical procedures achieved good clinical and radiological outcomes with bone and ligament injury repair. The screw group had a greater range of forearm supination than the plate group.

[Radial head prosthesis for acute fractures]

Non-reconstructible radial head fractures with concomitant injuries and resultant instability of the elbow are often treated by implantation of a radial head prosthesis. Various prosthetic designs and implantation techniques are available. Several pitfalls have to be respected during implantation. This article provides tips and tricks for successful implantation and aftercare and gives an overview of long-term outcomes and revision rates.

Radial head arthroplasty: a descriptive study of 970 patients in an integrated health care system

BACKGROUND

Radial head arthroplasty (RHA) is commonly performed for isolated comminuted radial head fractures and in conjunction with traumatic elbow instability. However, there is a paucity of literature directly describing the characteristics and outcomes of patients who undergo RHA in a community-based setting. We describe a cohort of 970 RHA performed in the California regions of a US integrated health care system over a 9-year period. Patient demographics, implant selection, 90-day acute postoperative events, and cumulative reoperation/revision rates are included.

METHODS

Patients aged ≥18 years who underwent primary RHA were identified (2009-2017). Patient characteristics and demographics, including age, body mass index, gender, diabetes status, American Society of Anesthesiologists (ASA) classification, primary diagnosis, and concomitant procedures were described. Crude cumulative revision and reoperation probabilities were calculated as 1 minus the Kaplan-Meier estimator, with follow-up time calculated as the time from the index RHA to revision/reoperation date for those with the outcome of interest and time from index RHA to censoring date (eg, date of death, health care termination, study end date [March 31, 2018]) for those without the outcome. Ninety-day postoperative incidence of emergency department (ED) visit, readmission, and mortality was calculated as the number of patients with the event of interest over the number of patients at risk.

RESULTS

A total of 970 patients underwent primary unilateral RHA by 205 surgeons during the study period. Annual procedure volume increased from 53 procedures in 2009 to 157 procedures in 2017. More patients were female, without diabetes, and had an ASA classification of 1 or 2. Fracture was the predominant indication for RHA (98.4%) and more than half (54.3%) had concomitant procedures performed. Most implants were press fit (63.2%) over loose fit, and >90% were monopolar. Three-year cumulative revision and reoperation probabilities following RHA were 6.5% (95% confidence interval [CI] = 5.0%-8.5%) and 8.2% (95% CI = 6.5%-10.3%), respectively. Revisions and reoperations tended to occur within the first postoperative year. Of the 970 RHA patients, 83 (8.5%) had a 90-day ED visit, 58 (6.0%) had a 90-day readmission, and 1 (0.1%) died within a 90-day postoperative period.

CONCLUSION

This large cohort of RHA patients provides information about the practice of RHA at large and in the community. Surgeons are performing more RHA over time and choosing press fit stems more often. Revisions and reoperations tended to occur early. Readmission and ED visits were low but not negligible, with pain being the most common reason for ED visit.