Radial Head Arthroplasty Research Articles

Three-Dimensional Evaluation Technique For Prosthesis Placement After Radial Head Arthroplasty

Three-Dimensional Evaluation Technique For Prosthesis Placement After Radial Head Arthroplasty

Stress Shielding Following Radial Head Arthroplasty: The Impact Of Preoperative Bone Quality

Stress Shielding Following Radial Head Arthroplasty: The Impact Of Preoperative Bone Quality

Outcome Of Revision Radial Head Arthroplasty With Deliberate Underlengthening Of A Cemented Bipolar Prosthesis

Outcome Of Revision Radial Head Arthroplasty With Deliberate Underlengthening Of A Cemented Bipolar Prosthesis

Elbow Kinematics With Increasing Radial Head Arthroplasty Overlengthening Evaluated With Dynamic Radiostereometric Analysis

Elbow Kinematics With Increasing Radial Head Arthroplasty Overlengthening Evaluated With Dynamic Radiostereometric Analysis

Automated coordinate system estimation: A preliminary step toward computer-assisted radial head arthroplasty planning.

The success of radial head arthroplasty (RHA) relies on the design of the implant and precision of the surgical technique, with preoperative planning potentially playing a crucial role. The accurate establishment of a patient-specific anatomical coordinate system (ACS) is essential for this planning process. This study tested the hypothesis that an innovative automated method would be an accurate, reliable, and efficient framework to determine the ACS of the proximal radius, which would be a step toward improving the precision of RHA planning. We used advanced computational techniques to analyze 50 forearm CT scans, comparing the accuracy, reproducibility, reliability, and efficiency of the automated method with manually derived ACS using expert observers as benchmarks. The results showed that the automated approach was more accurate in identifying anatomical landmarks, with smaller mean distance discrepancies (0.6 mm) than manual observers (1 mm). Its reproducibility was also superior, with narrower reproducibility limits, particularly for ulnar notch landmarks (0.6 to 0.8 mm compared to manual selection 1.2 to 1.4 mm) (p = .01). In addition, the limits of agreement and the mean absolute rotational and translational differences of the axes were narrower for the automated method, which also reduced the construction time to an average of 46 s compared to 150 s manually (p < .001). These findings suggest that the automated method has the potential to enhance the accuracy and efficiency of preoperative and postoperative computer-assisted procedures for RHA. Further research is needed to fully understand the utility of this automated system for enhancing RHA computer-assisted surgical planning.

Can a single question replace patient-reported outcomes in the follow-up of elbow arthroplasty? A validation study

BackgroundTo assess the results after elbow arthroplasty it is essential to gather patient-reported outcome measures (PROMs). However, the acquisition of PROMs poses a challenge because of potential low literacy, lengthiness and diversity of questionnaires, and questionnaire fatigue. Instead of a questionnaire, patient-reported outcomes can be collected using a single assessment numeric evaluation (SANE), the subjective elbow value (SEV). The aim of this pilot study is to assess the correlation between the SEV and conventionally used patient reported outcome measures (PROMs) after elbow arthroplasty.Materials and methodsThe SEV was added to our follow-up system in 2021, consisting of a scale from 0 to 10 in which the patients are asked to rate the overall functionality of their elbow, 0 corresponds to very poor functionality and 10 to a perfectly functional or healthy elbow. All patients who underwent elbow arthroplasty (total or radial head) and responded to the SEV question were retrospectively identified and included. The correlation between the SEV at the final follow-up and the Oxford Elbow Score (OES), and between the SEV and the Quick Disbailities of the Arm, Shoulder, and Hand (quickDASH) score was assessed using Pearson’s r.ResultsIn total, 82 patients responded to the SEV question and were included in the study, with a median follow-up of 5 years [interquartile range (IQR) 3–7]. Of these patients, 17 (21%) underwent radial head arthroplasty and 65 (79%) total elbow arthroplasty. The Pearson’s r for the correlation between SEV and OES was 0.502 (p < 0.001) and between the SEV and the QuickDASH −0.537 (p < 0.001), which correspond to a moderate correlation.ConclusionsThe SEV shows a moderate correlation with conventional PROMs, demonstrating its potential in simplifying the follow-up of elbow arthroplasty, possibly decreasing time, costs, and patients’ questionnaire fatigue compared with conventional PROM questionnaires.Evidence level: III.

The outcomes of surgical treatment of complex radial head fractures.

The aim of this study was to evaluate the outcome of complex radial head fractures at mid-term follow-up, and determine whether open reduction and internal fixation (ORIF) or radial head arthroplasty (RHA) should be recommended for surgical treatment. Patients who underwent surgery for complex radial head fractures (Mason type III, ≥ three fragments) were divided into two groups (ORIF and RHA) and propensity score matching was used to individually match patients based on patient characteristics. Ultimately, 84 patients were included in this study. After a mean follow-up of 4.1 years (2.0 to 9.5), patients were invited for clinical and radiological assessment. The Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score were evaluated. Patients treated with ORIF showed significantly better postoperative range of motion for flexion and extension (121.1° (SD 16.4°) vs 108.1° (SD 25.8°); p = 0.018). Postoperative functional scores also showed significantly better results in the ORIF group (MEPS 90.1 (SD 13.6) vs 78 (SD 20.5); p = 0.004). There was no significant difference between the groups in terms of the complication rate (RHA 23.8% (n = 10) vs ORIF 26.2% (n = 11)). Implant-related complications occurred in six cases (14.3%) in the RHA group and in five cases (11.9%) in the ORIF group. Irrespective of the patient's age, sex, type of injury, or number of fracture fragments, ORIF of the radial head should be attempted initially, if a stable reconstruction can be achieved, as it seems to provide a superior postoperative outcome for the patient compared to primary RHA. If reconstruction is not feasible, RHA is still a viable alternative. In the surgical treatment of complex radial head fractures, reconstruction shows superior postoperative outcomes compared to RHA. Good postoperative results can be achieved even after failed reconstruction and conversion to secondary RHA. Therefore, we encourage surgeons to favour reconstruction of complex radial head fractures, regardless of injury type or number of fragments, as long as a stable fixation can be achieved.

Elbow kinematics with increased lengthening of a radial head arthroplasty evaluated with dynamic radiostereometric analysis.

The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA). Eight human donor arms were examined by dRSA during motor-controlled flexion and extension of the elbow with the forearm in an unloaded neutral position, and in pronation and supination with and without a 10 N valgus or varus load, respectively. The elbows were examined before and after RHA with stem lengths of anatomical size, + 2 mm, and + 4 mm. The ligaments were maintained intact by using a step-cut lateral humeral epicondylar osteotomy, allowing the RHAs to be repeatedly exchanged. Bone models were obtained from CT scans, and specialized software was used to match these models with the dRSA recordings. The flexion kinematics of the elbow were described using anatomical coordinate systems to define translations and rotations with six degrees of freedom. The greatest kinematic changes in the elbows were seen with the longest, + 4 mm, implant, which imposed a mean joint distraction of 2.8 mm in the radiohumeral joint and of 1.1 mm in the ulnohumeral joint, an increased mean varus angle of up to 2.4° for both the radius and the ulna, a mean shift of the radius of 2.0 mm in the ulnar direction, and a mean shift of the ulna of 1.0 mm posteriorly. The kinematics of the elbow deviated increasingly from those of the native joint with a 2 mm to a 4 mm lengthening of the radius. This confirms the importance of restoring the natural length of the radius when undertaking RHA.

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.

Minimum 10-year Follow-up after Open Reduction and Internal Fixation of Radial Head Fractures Mason Type II and III

The treatment of complex radial head fractures remains controversial with open reduction and internal fixation (ORIF), radial head arthroplasty, and radial head excision being the most common treatment options. While ORIF is the preferred treatment strategy for Mason type II fractures, the optimal treatment of Mason type III fractures is debated. To report minimum 10-year outcomes after ORIF of Mason type II and type III radial head fractures. We hypothesized that both Mason Type II and Type III fracture patients would demonstrate satisfactory clinical outcomes at minimum 10-year follow-up. All patients with Mason type II or III radial head fractures who were treated with ORIF by a single surgeon between 2005 and 2010 were included. Fractures with significant bone defects were treated with bone grafts and elbow ligament injuries were treated with either primary ligament repair or reconstruction. Patient reported outcome (PRO) questionnaires were administered at the time of last clinical follow-up and at a minimum of 10 years postoperatively. Twenty-four patients, including 13 male and 11 female patients with an average age of 39 (range 19-60) at the time of surgery met inclusion criteria. Thirteen patients suffered from Mason type II and 11 patients from Mason type III fractures. At initial follow-up, 21 out of 24 fractures (88%) demonstrated radiographic union. Three non-unions, 2 of which were Mason type III fractures, were treated with revision ORIF and iliac crest bone grafting. 11 patients developed postoperative elbow stiffness and required capsular release surgery. At last clinical follow-up, average flexion was 139 degrees, average extension was 4 degrees, average supination was 77 degrees, and average pronation was 81 degrees. The median DASH score was 7 (ranging from 0 - 32). Minimum 10-year follow-up (mean: 14.6 years) was collected on 18 of 24 (75%) of the patients. At a minimum of 10 years postoperatively, the median QuickDASH score was 4.5 (range: 0 to 25) and the median SANE score was 96.5 (range: 75-100). Median satisfaction with the surgical outcome was 10/10 (range: 3-10). ORIF of Mason type II and III radial head fractures results in high union rates with good functional outcomes at a mean of 14.6 years postoperatively. The study results suggest that ORIF of Mason type II and III radial head fractures leads to long-term positive functional outcomes.

The Trans-Olecranon Approach for a Concomitant Radial Head Arthroplasty and Internal Fixation of the Ulna in Monteggia-Equivalent Fractures

Background: Monteggia-equivalent fractures are similar to Monteggia fractures but involve different patterns and locations. When these fractures include a severe radial head fracture, radial head arthroplasty (RHA) should be considered. RHA can be performed using Kocher’s approach or the less commonly used trans-olecranon approach, which has been less studied. This study evaluates the clinical and radiological outcomes of the trans-olecranon approach for RHA over 15 years. Methods: In this retrospective study, 45 cases of Monteggia-equivalent fractures were analyzed, focusing on patients over 18 with radial head fractures, treated by the same surgeon with RHA and open reduction and internal fixation (ORIF) of the proximal ulna via the trans-olecranon approach. Results: The cohort of 45 patients showed a mean flexion of 112.37° ± 13.7°, mean extension of 24.27° ± 17.9°, mean supination of 57.63° ± 28.9°, and mean pronation of 62.16° ± 29.07°. Clinical and radiographic measurements indicated satisfactory results, with acceptable complication and secondary procedure rates. Conclusion: The trans-olecranon, single-incision approach is effective for managing fractures involving the proximal ulna and radial head, offering adequate access to lateral elbow structures while minimizing damage to surrounding soft tissue. Therefore, this approach should be considered for patients presented with a Monteggia-equivalent fracture and an indication for RHA.

Short- to midterm outcomes of 139 pyrocarbon monopolar radial head arthroplasties

The MoPyc radial head arthroplasty (RHA) is a monopolar implant with a pyrocarbon head that obtains rigid fixation via controlled expansion of the titanium stem. The aim of this study was to evaluate the short to midterm outcomes of MoPyc RHA. Between 2002 and 2021, 139 MoPyc RHA were implanted in 139 patients with a RH fracture. The mean follow-up was 5.9 years ±3.5 (range 1-16). Range of motion, mean Mayo Elbow Performance score (MEPS), quick disabilities of the Arm, Shoulder and Hand (quickDASH) score, visual analog scale (VAS), radiographic outcome, and reason for failure were recorded. The mean MEP, QuickDASH, and VAS scores were 89.1± 2.2(range, 45-100), 17.5±16.7(range, 0-78), and 0.8±1.6(range, 0-50), respectively. Stress shielding (SS) and osteolysis around the stem (OAS) were identified in 92(66%) and 20(14%) patients. A total of 47(29%) patients experienced at least one complication; and 29(21%) of them required re-intervention. Persistent stiffness (n=12;9%) was the most common complication. No painful loosening was noted. Osteolysis around the stem, presence of an autoexpanding stem, and overstuffing were associated with a lower MEPS and an increase in VAS (p<0.05). Stress shielding (SS) was associated with an increase in MEPS (aβ=6.92; p<0.001) and lower VAS (aβ=-0.69; p=0.016). The auto-expending stem increased the likelihood of SS after RHA (aOR=1.49; p=0.001). A well-fixed MoPyc RHA provided satisfactory short to midterm outcomes, without painful loosening. However, the autoexpanding stem system was associated with poorer functional outcomes and increased the likelihood of SS.

A Systematic Review and Network Meta-Analysis of Randomised Controlled Trials Comparing Treatments for Displaced Radial Head Fractures.

Background: The aim of this study is to compare the surgical and non-operative management of displaced radial head fractures via a network meta-analysis of randomised controlled trials (RCTs). Methods: RCTs comparing management of isolated, displaced radial head fractures in adults were included in our review and statistical analysis. A systematic review of electronic databases (Medline, Embase and Cochrane Library) were screened for comparative RCTs reporting on the management of displaced radial head fractures in August 2021. Two investigators independently reviewed studies for eligibility and an assessment of bias was performed for each study. A Bayesian network meta-analysis of the included RCTs was performed. Results: Five RCTs (326 patients) were included in our meta-analysis. Treatment methods included radial head arthroplasty (RHA), open reduction internal fixation (ORIF) with metal implants (ORIF-M), ORIF with biodegradable implants (ORIF-B) and non-operative management. In our network meta-analysis of 'good' or 'excellent' patient-reported outcome measures (PROMs), RHA was significantly favourable to ORIF-M (OR: 0.04, CrI: 0.0011, 0.87), ORIF-B (OR: 0.1 CrI: 0.00076, 6.37). Nonoperative treatment was not shown to be significantly worse than RHA (OR: 0.01 CrI: 2.5e-0.5, 3.61). Conclusions: This network meta-analysis shows that in displaced radial head fractures, RHA is associated with significantly superior functional PROMs than ORIF-M based on the evidence available. Nonoperative management has not been shown to be significantly worse. Level of Evidence: Level III (Therapeutic).

Radial head arthroplasty diameter impact on elbow kinematics evaluated by dynamic radiostereometric analysis.

Radial head arthroplasty (RHA) reestablishes elbow stability after complex radial head fracture, but complication rates are high, possibly due to inappropriate implant sizing. Knowledge of impact of radial head implant diameter on elbow kinematics is limited and warranted. This study evaluated elbow kinematics of different radial head implant diameters after RHA using dynamic radiostereometric analysis (dRSA). Eight human donor arms were examined with dRSA during elbow flexion with the forearm in unloaded neutral position, and in supinated- and pronated position without and with 10N either varus or valgus load, respectively. Elbow kinematics were examined before and after RHA with head diameters of anatomical size, -2 mm (undersized), and +2 mm (oversized). The ligaments were kept intact by use of step-cut humerus osteotomy for repeated RHA exchange. Bone models were obtained from CT, and by AutoRSA software bone models were matched with dRSA recordings. The elbow kinematics were described using anatomical coordinate systems. Compared to the native radial head during elbow flexion, the anatomical sized RHA shifted 2.0 mm in ulnar direction during unloaded pronated forearm position. The undersized RHA shifted 1.5 mm in posterior direction and 2.1 mm in ulnar direction during unloaded pronated forearm position and increased the varus angle by 2.4° during supinated loaded forearm position. The oversized RHA shifted 1.6 mm in radial direction during loaded supinated forearm position. The anatomically sized RHA should be preferred as it maintained native elbow kinematics the best. The kinematic changes with oversized and undersized RHA diameters were small, suggesting forgiveness for the RHA diameter size. Level III.

Osteosynthesis and radial head arthroplasty achieve comparable and favorable results in terrible triad injury: a systematic review using propensity score matching

The terrible triad literature reports data across wide ranges of patients ages and the treatment allocation for the radial head is commonly based on fracture severity. These observations raise the question of selection bias which can hinder comparative efficacy. Propensity score matching analysis may provide better control of patient variables and treatment allocation. We convey two conclusions from this analysis. Firstly, clinical outcome metrices were favorable for both radial head arthroplasty and open reduction internal fixation following terrible triad injury. This finding supports the recent literature which describe satisfactory outcomes for acute surgical management of these injuries. Secondly, the analysis suggests that revision rates may be lower for both treatment options than previously reported in the literature.

Head-to-neck screw fixation and radial head arthroplasty result in similar postoperative outcomes for low-comminuted radial head fractures with neck involvement

Background Fixation of radial head fractures with neck involvement presents challenges. It remains unclear whether the outcomes of head-to-neck screw fixation are similar to those of arthroplasty in this scenario. We conducted a retrospective cohort study to evaluate the clinical outcomes of these two methods for treating such fractures. Methods Demographic data, fracture type, number of fragments, and concomitant injuries were recorded. Range of motion, Visual Analogue Scale for pain, Mayo Elbow Performance Score, and Quick-Disabilities of the Arm, Shoulder, and Hand at three-year follow-up, complications, and reintervention were compared. Results A total of 14 patients underwent fixation with head-to-neck screws, and 15 an arthroplasty. Baseline characteristics between groups were similar ( P &gt; .05). Satisfactory range of motion (arc &gt; 100°) was achieved in nine patients (64%) in the fixation group, and eight patients (53%) in the arthroplasty group ( P = .55). The mean Visual Analogue Scale, Mayo Elbow Performance Score, and Quick-Disabilities of the Arm, Shoulder, and Hand were 1.2 ± 1.2, 91.7 ± 10.7, and 9.1 ± 1, respectively, ( P = .651, P = .651, and P = .155). Three patients (21%) in the fixation group underwent a reintervention and three (20%) in the arthroplasty group ( P = .639). Discussion Head-to-neck screw fixation and radial head arthroplasty result in similar postoperative outcomes for low-comminuted radial head fractures with neck involvement.

Usefulness of multiple bioabsorbable Mg screws/K‑wires for comminuted radial head fractures.

We hypothesized that multiple absorbable screws/K-wires would be effective for native head preservation in comminuted radial head fracture fixation (com-RHFs). Seventeen patients who met the inclusion criteria between 2018 and 2020 were included. Radiologic findings indicating proper union and clinical outcomes such as the range of elbow motion, visual analog scale score, and Mayo Elbow Performance Score were assessed prospectively after surgery and at least threeyears of follow-up. The mean follow-up period was 4.6years. Eleven, one, three, and two patients presented with isolated com-RHFs, type 2 (accompanied injury of medial collateral ligament), type 4 ("terrible triad") fractures, and type 5 posterior olecranon fracture-dislocations, respectively. Union was achieved after a mean of nineweeks postoperatively. The head and shaft angles did not differ significantly from the contralateral normal values (p = 0.778 and 0.872, coronal and sagittal, respectively). At the final follow-up, the mean flexion-extension/pronation-supination arcs were 126.47 ± 4.92°/135.59 ± 10.13°, and thus were significantly different from those on the contralateral side (p < 0.001, both), however the arcs were functional ranges for ordinary daily life. Also, functional status was satisfactory in all individuals. The arthritis grade and extent of heterotrophic ossification were satisfactory in all cases, and there were no serious complications requiring revision surgery. Absorbable screw/K-wire fixation for com-RHFs is an option before radial head arthroplasty associated with a low complication rate and no need for revision.

Does the polarity of radial head arthroplasty affect functional outcomes? A systematic review and meta-analysis.

Radial head arthroplasty allows a high degree of customizability, and implant polarity has emerged as an important variable. The purpose of this meta-analysis was to evaluate differences in functional and clinical outcomes between patients receiving monopolar and bipolar radial head prosthetic implants. A systematic review and meta-analysis were employed, and 65 articles were identified in three databases. Twelve articles contained non-English or insufficient text and were consequently excluded, and 20 others did not contain sufficient data or follow-up. The remaining 33 articles were qualitatively and quantitatively reviewed. In total, 33 populations were identified, with 809 unduplicated patients: 565 with monopolar and 244 with bipolar implants. In these respective patients, the mean follow-up was 40.2 and 56.9 months. Average Mayo Elbow Performance Score were 86.7 and 87.4 (P=0.80), respectively; average Disability of the Arm, Shoulder, and Hand scores were 17.9 and 14.7 (P=0.47), and average final flexion/extension arcs were 119.4° and 118.7° (P=0.48). Revision rates were 4.07% and 6.56%, while complication rates were 19.65% and 20.08% in the respective monopolar and bipolar patients. These increased relative risks associated with bipolar implants were not significant. Radial head implant polarity does not appear to affect functional outcomes. While bipolar prosthetic design may increase the risks of revision and complications, the increases were not significant. Level of evidence: IV.

Long-terms outcomes of radial head arthroplasty using a bipolar prosthesis.

In acute treatment of radial head fractures, a radial head prosthesis can be considered if open reduction and internal fixation are not technically feasible. We reviewed the data of 27 consecutive bipolar Judet radial head prostheses implanted in patients with unreconstructable radial head fractures and no other concomitant fractures (coronoid or olecranon factures). The lesions of the lateral collateral ligament were rated according to the McKee classification. Twenty-three patients with more than ten-year follow-up participated in this retrospective study All patients underwent assessments for pain, range of motion and stability using the Mayo Elbow Performance Score, the QuickDash questionnaire and a Visual Analogue Scale for pain. Radiography assessment was performed to determine the correct setting of the implant, presence of periprosthetic loosening, prosthetic disassembly, heterotopic ossification, capitellum and ulnohumeral degenerative changes. Mean follow-up was 149 months (± 12.2). Mean range of motion in flexion-extension was 111° (± 10.55), mean extension was 18° (± 14.32) and mean flexion was 130° (± 11.4). Mean arc of motion in supination-pronation was 150° (± 12.26). The mean Mayo Elbow Performance Score was 88, the mean QuickDash score was 7.3; 86% of the patients were satisfied. Seven patients (26%) required secondary surgery. The most frequent complication was heterotopic ossification, which had negative consequences on the functional result. Bipolar radial head prostheses are an option for acute treatment of isolated unreconstructable radial head fractures. During follow-up, three patients required implant revision and removal; the capitellum surface presented severe degenerative changes and the prosthesis was not replaced. Another complication was the risk of implant dislocation, in relation to implant design, incorrect positioning of the radial head stem or else to inadequate reconstruction of the lateral collateral ligament. Further work is needed to establish the long-term follow-up results of Judet implants in complex elbow fractures.

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

BackgroundThe incidence of radial head fractures is increasing, and radial head arthroplasty (RHA) is being more frequently utilized as treatment for irreparable fractures. Our objective was to compare radiocapitellar pressure between the native joint and two 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. MethodsTen cadaveric specimens received a pressfit radial head prosthesis (Align, Skeletal Dynamics, Miami, FL) for both prosthetic testing conditions. Anatomic alignment (AL) was defined as the prosthetic head aligned to the forearm axis of rotation. Axisymmetric alignment (NA) 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 was collected using a Tekscan 4000 sensor. ResultsThe mean pressure in the AL and AX groups were significantly higher than the mean pressure in the native joint. Compared to 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 zero specimens in the native joint group, in one specimen (10%) in the AL group, and in five specimens (50%) in the AX group. DiscussionOur 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 non-aligned pressfit prosthesis. These findings suggest that anatomic alignment may optimize capitellar wear properties, improving the long-term durability of radial head arthroplasty.