Radial head replacement with the MoPyC pyrocarbon prosthesis

Stress shielding following radial head arthroplasty: the impact of preoperative bone quality

BACKGROUND

We sought to assess if the medullary diameter to cortical width ratio (MD:CW), canal flair index (CFI), and canal fill (CF) of the proximal radius were associated with the presence of stress shielding (SS) after a MoPyC radial head arthroplasty.

MATERIALS AND METHODS

We conducted a retrospective, international, multicenter (4 centers) study. A total of 100 radial head arthroplasties in 64 women and 36 men with a mean age of 58.40 years ± 14.90 (range, 25.00-91.00) were included. Radiographic measurements, including MD:CW, CFI, CF, and postoperative SS were captured at a mean follow-up of 3.9 years ± 2.8 (range, 0.5-11).

RESULTS

SS was identified in 60 patients. Mean preoperative MD:CW, CFI, and CF were 0.55 ± 0.09, 1.05 ± 0.18, and 0.79 ± 0.11, respectively. The presence of SS was significantly associated with MD:CW (adjusted odds ratio = 13.66; P = .001), and expansion of the stem (adjusted odds ratio = 3.78; P = .001). The amount of the SS was significantly correlated with expansion of the stem (aβ 4.58; P < .001).

CONCLUSIONS

Our study found that MD:CW was an independent risk factor of SS after MoPyc radial head arthroplasty. Autoexpansion of the MoPyc stem significantly increased the risk of SS and its extent. Further studies involving multiple implants designs are needed to confirm the preliminary observations presented in the current study.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

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.

Midterm outcomes of a short-cemented bipolar radial head arthroplasty, in a cohort of 56 cases with minimum 2-years follow-up

BACKGROUND

Radial head prostheses are used in comminuted radial head fractures for elbow stabilisation when reduction and internal fixation is not possible. Several implant designs exist, but no large series exist about a short-cemented and bipolar implant.

HYPOTHESIS

The hypothesis was that this prosthesis design shows good clinical, functional, and radiological results, with acceptable rate of complications.

STUDY DESIGN

This retrospective study included the prostheses with bipolar design and short-cemented stem (Evolutive™), with a minimum 2-years follow-up.

MATERIALS AND METHODS

All prosthesis implanted in our Traumatology Center were included, with minimum 2-years follow-up. The evaluation consisted of a clinical and functional evaluation, associated with an independent radiographic assessment. All complications were listed, as long as rate and reasons for implant removal.

RESULTS

Fifty-six implants were studied with a mean follow-up of 64.9months (24 to 119). Fifty-three cases were acute injuries with 16% isolated radial head fractures and 76% complex elbow injury such as ulno-humeral, radio-ulnar or longitudinal forearm instability. Fifty (89%) implants were still in place at last follow-up. The main reason for implant removal was during arthrolysis procedure. Ranges of motion were: 126° in flexion, 9° of extension loss, 76° of pronation and 79° of supination. Mean Mayo Elbow Performance Index was 84.1 with 72% of excellent or good results, and the median quick-DASH was rated 18.2. Radiographic evaluation found 12% significant ulno-humeral arthtitis, 64% capitellar osteopenia and 12% loosening. We recorded 5% of implant-related complications.

DISCUSSION

The short-cemented stem bipolar radial head prosthesis presents clinical and functional results similar to other radial head prosthesis with low incidence of elbow arthritis, when treating both isolated radial head fracture or complexes elbow injury. This implant should therefore be valid for treating comminuted radial head fractures in all types of traumatological injuries.

LEVEL OF EVIDENCE

IV; Retrospective cohort study.

Pyrolytic carbon head shoulder arthroplasty: CT scan glenoid bone modeling assessment and clinical results at 3-year follow-up

Background

The aim of this study is to report the radiological glenoid modifications and clinical outcomes at 3 years mean follow-up of hemi shoulder arthroplasty (HA) with pyrocarbon (PYC) humeral head. Our hypothesis was that the PYC implants would provide good outcomes without major glenoid erosion. Additionally, we hypothesized that HA-PYC allowed for remodeling of the bone.

Methods

Patients underwent HA with PyC humeral head for treatment of primary or secondary osteoarthritis, excluding post-traumatic cases. All patients had a Constant Score assessed preoperatively and at the last follow-up. Preoperative and postoperative computed tomography scans at the last follow-up were performed to achieve 3-dimensional reconstructions of the scapulae. Deformities of the glenoid surface were analyzed as a distance differential between postoperative and preoperative to investigate potential bone remodeling vs. glenoid erosion. The subluxation index (SLI) was measured.

Results

We included 41 patients implanted with a HA-PYC. Average age at the time of implant was 63.8 (40 to 79 years). All patients were followed for ≥2 years with an average follow-up of 36.3 months (24 to 60 months). Constant Scores increased from 34 at baseline to 80 at the last follow-up points on average (P < .01). Return to work rate was 100% and 96% had resumed their physical activity. Ten (77%) of the 13 patients with posterior head subluxation had normalized their SLI. Furthermore, no significant differences were detected between the individuals having corrected their posterior subluxation and the others (preoperative SLI between 0.45 and 0.55). Glenoid wear is less than 0.6 mm at 3 years mean follow-up, ie, 5 times less than metallic implants. A tendency to recenter the head in the anteroposterior plane was found in type B glenoid, without increased erosion of the glenoid, with very good clinical results. We did not find any difference according to age or glenoid type for clinical and radiological results.

Conclusion

HA-PYCs give, in the short term, excellent clinical results in terms of pain and function. The development of a precise and objective measurement method has made it possible to demonstrate that the glenoid surface is the site of modifications that may be part of bone remodeling or progression of the osteoarthritis disease.

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.

Radial Head Arthroplasty for Fracture: Implant Survivorship and Outcomes at Mean Follow-up of 8 Years

PURPOSE

The purpose of this study was to evaluate implant survivorship and clinical outcomes following radial head arthroplasty for fracture at long-term follow-ups.

METHODS

A retrospective analysis was conducted on adult patients who underwent primary uncemented radial head arthroplasty for radial head or neck fractures between 2012 and 2015. Medical records were reviewed to collect information regarding demographics, injury characteristics, reoperations, and revisions requiring implant removal. A bivariate analysis was conducted to identify potential risk factors for reoperation. A Kaplan-Meier curve was created to determine implant survival rates. Eligible patients were contacted to confirm any reoperations and obtain Quick Disability of the Arm, Shoulder, and Hand scores at long-term follow-ups.

RESULTS

A total of 89 patients were eligible for analysis and assessed at a mean of 97 months after surgery (range, 81-128). Reoperation rate was 16% (14 of 89 patients), including 5% of patients requiring implant removal or revision. However, 93% of reoperations occurred within the first 12 months of the index surgery. Fracture dislocations of the elbow had a higher rate of reoperation. A Kaplan-Meier curve demonstrated an implant survival rate of 96% at 10-year follow-up. Of the patients who responded, the mean Quick Disability of the Arm, Shoulder, and Hand score was 8.7 ± 10.3, with none requiring additional reoperations or revisions. There were otherwise similar outcome scores among patients requiring reoperation versus those who did not.

CONCLUSIONS

Although radial head arthroplasty for fractures has a high potential for reoperation within the first year, survival rates with uncemented implants remain high at 10 years, and patients report excellent Quick Disability of the Arm, Shoulder, and Hand scores at long-term follow-ups, despite any need for reoperation. Fractures with associated elbow dislocation may be at a higher risk for reoperation, and it is important to provide this prognostic information to patients who are likely to require arthroplasty for more extensive injuries.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Treatment of comminuted radial head fractures with personalized radial head prosthesis produced with 3-dimensional printing technology

BACKGROUND

The radial head is the forearm's pivot point for supination-pronation. Although radial head resection can be performed in comminuted radial head fractures, radial head prosthesis has gained popularity in order to prevent possible complications such as progressive valgus instability in the elbow and secondary ulnocarpal impaction that may develop due to proximal displacement of the radius. As for radial head prostheses, standard prosthetic designs do not provide the same results in everyone, and the alignment of the radial head and radial neck angle cannot be fully achieved. We believe that the radial head must be reconstructed with a complete anatomical implant. We designed and applied personalized prostheses to our patients, and in this study, we wished to share the 2-year results of these patients.

METHODS

In this study, 23 patients who had comminuted radial head fractures had personalized radial head prostheses inserted. Preoperative variables such as type of injury, age, side, additional ligament injury, operation time, number of radial head parts, neck angle of individual prosthesis, stem length, and stem diameter were noted. The mean operating time was 26 ± 9 minutes. One month postoperatively, after physical therapy, elbow range of motion, loss of strength compared to the opposite joint, Mayo elbow scores, QuickDASH scores, and patient satisfaction were evaluated. Patients were evaluated 2 years postoperatively.

RESULTS

QuickDASH and Mayo elbow scores were satisfactorily good (mean QuickDASH score: 9.091, mean Mayo score: 91.08). According to the results of the patient satisfaction questionnaire, 16 of the 23 patients reported excellent satisfaction, 5 patients good satisfaction, and 2 patients moderate satisfaction. None of the patients reported poor results.

DISCUSSION

Since personalized radial head prosthesis consists of a single monoblock, its surgical application consists of a single step and has a short operating time. As the applications in the literature increase and more studies are conducted, this subject will be better understood. Our study demonstrated that these patients, whose anatomies were individually replicated, achieved good range of motion and patient satisfaction. In fact, none of the patients reported negative results. In comminuted radial head fractures, surgical implantation of personalized radial head prosthesis is a treatment modality with easy application, short operating time, and good functional results.

Pyrocarbon unipolar radial head prosthesis: clinical and radiologic outcomes at long-term follow-up

BACKGROUND

Several studies have already reported good short-term results with a pyrocarbon unipolar radial head prosthesis (Pyc-uRHP). The aim was to evaluate the evolution from mid- to long-term clinical and radiographic outcomes of a Pyc-uRHP.

METHODS

This was a retrospective, single-center study. We followed up all the patients who underwent Pyc-uRHP surgery in our original study at 2 years of follow-up (52 patients), reaching a minimum of 7 years of clinical and radiologic follow-up. This study included 26 patients who underwent a clinical examination assessing mobility, the Mayo Elbow Performance Score, and the visual analog scale score and radiologic evaluation with anteroposterior and profile radiographs at a mean follow-up of 110 months (range, 78-162 months). The radiologic study analyzed signs of proximal osteolysis, stem loosening, capitellar wear, and humeroulnar osteoarthritis.

RESULTS

No patients required revision. Eight patients required reoperation: coronoid screw removal in 1 and arthrolysis for stiffness in 7. The mean time to reoperation was 11 months. The mean Mayo Elbow Performance Score at last follow-up was 96 ± 9 (of 100), with a pain score of 42 ± 7 (of 45), mobility score of 19 ± 2 (of 20), stability score of 10 (of 10), and function score of 25 (of 25). Comparison with clinical data from the mid-term delay did not reveal any significant difference. All patients presented with proximal osteolysis around the neck but without progression. No stem loosening was noted. The rates of humeroulnar osteoarthritis (12% at mid-term vs. 80% at last follow-up, P < .0001) and capitellar lesions (34% at mid-term vs. 80% at last follow-up, P = .001) increased significantly.

CONCLUSION

We have shown that a Pyc-uRHP at 9 years' follow-up provided stable and satisfactory clinical results. Osteolysis of the radial neck was always present but it did not evolve, and no stem loosening was noted. Finally, we have shown a clear worsening of radiologic humeroulnar osteoarthritis and capitellar lesions that remained asymptomatic.

Pyrocarbon Arthroplasty Implants in the Upper Extremity: A Systematic Review of Outcomes and Pooled Analysis of Complications

BACKGROUND

Growing use of pyrocarbon implants in upper extremity arthroplasty has culminated in a breadth of literature ascertaining outcomes and complications at long-term follow-up. However, at present, the literature remains devoid of studies synthesizing the available evidence for upper extremity surgeons to adequately assess the safety and utility of these implants relative to other available options.

METHODS

A systematic search of the National Library of Medicine, MEDLINE, and Embase databases was performed to determine clinical outcomes and complication and reoperation rates following pyrocarbon arthroplasties in the upper extremity. A breakdown of complication and reoperation rates for each independent joint (shoulder, elbow, wrist, and hand joints), and according to specific causes necessitating surgery, was also compiled.

RESULTS

A comprehensive summary of functional outcomes following upper extremity pyrocarbon arthroplasties is presented. Overall complication and reoperation rates in the hand and wrist were determined to be 28.2 percent and 17 percent, respectively. The proximal interphalangeal joint was associated with the highest complication rate (42.7 percent), followed by carpometacarpal joint (18.8 percent), metacarpophalangeal joint (17.6 percent), wrist (16 percent), elbow (15.7 percent), and shoulder (12.9 percent). In the hand and wrist, major complications included dislocations and subluxations (8.4 percent), stiffness and limited motion (4.4 percent), deformity (3.1 percent), hardware failure (1.9 percent), fractures (1.7 percent), persistent pain (1.7 percent), and infections (0.9 percent).

CONCLUSION

In the absence of large clinical trials, systematic reviews such as these can help inform clinical guidelines and provide practitioners with an evidence-based reference to improve informed consent.

Outcomes of press-fit radial head arthroplasty following complex radial head fractures

INTRODUCTION

Press-fit radial head arthroplasty (RHA) is increasingly popular in treating complex radial head fractures. This study assessed the outcome of RHA, including the outcome following re-operation, and explored potentially influencing factors.

HYPOTHESIS

Complex radial head fractures treated with press-fit radial head prosthesis would have a favourable outcome.

MATERIAL AND METHODS

Data on all consecutive patients treated with anatomic press-fit RHA from February 2002 to February 2015 were analysed. Post-surgery clinical and X-rays assessments included a post-discharge evaluation of function. Standardised methods implemented include the assessment of range of motion (ROM), the Mayo Elbow Performance Score (MEPS) and subjective satisfaction scales.

RESULTS

Forty-five patients were recruited and 71% were classified in Mason IV and 62.2% had the "terrible triad". Re-operation was performed in 26.7% and prosthesis removal in 15.6%. Mean follow-up was 140.8 months (95% CI 117.7-164) and prosthesis survival was 69.5% at 24 months. Mean MEPS before re-operations was 86.3±15.9. Pain and/or instability were the most common reasons for re-operation, and re-operations were significantly more frequent in patients having one or more "associated injuries" (p=0.05), but not the terrible triad; and in patients with radiological "loosening" signs (p<0.01). Subjective scores were relatively good in most patients, although the functionality perceived in the re-operation with implant removal group was rather low.

DISCUSSION

Several studies of complex radial head fractures treated with press-fit radial head prosthesis have also shown favourable results, but the patients in such studies generally had less severe lesions. Moreover, differently from previous reports, this study with a long follow-up has included a younger population with high functionality requirements. Pain and/or instability, as observed in several previous reports, were the most common reasons for re-operation, but contrary to the expectation, the terrible triad was not associated with unfavourable outcome.

CONCLUSION

Treatment of complex fractures with press-fit radial head prosthesis, including re-operation with implant removal yields satisfactory results. Most scores of functional and subjective outcome improved following the re-intervention and most patients returned to their usual occupation.

LEVEL OF EVIDENCE

Level IV; case series; treatment study.

In vitro comparison of wear characteristics of PyroCarbon and metal on bone: Shoulder hemiarthroplasty

BACKGROUND

There are concerns regarding glenoid erosion with metal shoulder hemiarthroplasty. PyroCarbon may offer an alternative because of favorable wear characteristics and preservation of the glenoid. The purpose of this study was to assess in vitro bone wear characteristics of PyroCarbon relative to cobalt chromium alloy hemiarthroplasty in a shoulder wear simulator.

METHODS

Wear of PyroCarbon and cobalt chromium prostheses articulating with bone were characterized by means of bone wear penetration rate, changes to surface roughness, and wear particle analysis.

RESULTS

PyroCarbon prostheses produced significantly less damage to bone and were less damaged by the bone than cobalt chromium prostheses. Cobalt chromium testing was halted at approximately 320,000 cycles because the bone was consumed. Wear testing of PyroCarbon specimens continued through five million cycles. Linearized bone penetration rate, bone volume loss rate, and surface roughness for cobalt chromium test specimens were 30 times greater than for PyroCarbon.

CONCLUSIONS

Results demonstrate significantly less damage to bone in simulated shoulder function testing for PyroCarbon hemiarthroplasty implants relative to conventional cobalt chromium implants. Our study supports use of PyroCarbon in humeral head hemiarthroplasty as a viable alternative to conventional metal hemiarthroplasty. Further investigation of PyroCarbon performance in clinical settings is warranted.

Management of the failed radial head arthroplasty

Primary radial head arthroplasty (RHA) produces good or excellent results in approximately 85% of patients. However, complications are not uncommon and have been described in up to 23% of cases.

The number of RHA is increasing, and consequently the absolute number of complications is expected to rise as well. The decision on whether to revise or remove the prosthesis seems more likely to depend on the preference of the surgeon or the hospital, rather than on objectifying problems with the prosthesis.

The current article presents an algorithm for the work-up and treatment of most complications that can occur following RHA.

Five subgroups of problems were identified: osteoarthritis, stiffness, instability, infection and implant-related issues.

In short, the preferred treatment depends mainly on the chondral condition and stability of the elbow joint.

Cite this article: EFORT Open Rev 2020;5:398-407. DOI: 10.1302/2058-5241.5.190055

Evaluation of two different types of radial head prosthesis in practical use. Using either Evolve® or MoPyC® radial head prosthesis in the treatment of comminuted radial head fractures

The aim of this retrospective study was to undertake a comparative evaluation of the Evolve^® modular metallic radial head implant prosthesis and the MoPyC^® pyrocarbon prosthesis in acute care. Seventyfive patients having a comminuted radial head fracture with an Evolve^® prosthesis (=G1) and 11 with a MoPyC^® prosthesis (=G2) were available for a follow-up. Postoperative patient outcomes were evaluated according to a standardized follow-up protocol which included the Morrey rating system. Assessment criteria were range of motion (ROM), functional scores, and rate of complications. G1 showed a mean Morrey score of 86 points. Four direct prosthesis complications were observed in this group (n=75). The average achieved Morrey score in G2 was 84 points. In this group (n=11), 2 direct prosthesis complications were diagnosed. The average range of motion did not differ greatly between both groups. Radial head replacement with either prosthesis yielded sufficient to satisfactory results in a mid-term perspective regarding the range of motion and function of the elbow joint when performed in carefully selected patients. The Evolve^® Prothesis appears to show a slightly lower rate of complication by way of a similar functional outcome.

Radial head arthroplasty: fixed-stem implants are not all equal-a systematic review and meta-analysis

Background

Numerous fixed-stem implants exist for radial head arthroplasty; therefore, we conducted a systematic review to compare the safety and efficacy of different types of fixed-stem implants.

Methods

We conducted a literature search, updated from a previous systematic review, to identify studies evaluating a fixed-stem radial head arthroplasty implant for any indication. We extracted data on revision rates, specific complications, and functional scores. We pooled results across studies using a random-effects method, using proportions for dichotomous data and mean values for functional scores. We analyzed outcomes by indication and specific implant.

Results

We included 31 studies. Studies included patients with radial head fractures only, terrible-triad injuries, or Essex-Lopresti injuries or included a heterogeneous population. We identified 15 different fixed-stem implants. The results of our analysis revealed that patients with terrible-triad injuries may be at an increased risk of revision and instability and patients with Essex-Lopresti injuries may be at an increased risk of arthritis, capitellar erosion, and osteolysis. After removing these outliers and pooling the results by specific device, we observed variability across devices in the rates of revision, arthritis, capitellar erosion, instability, and osteolysis, as well as in functional scores.

Conclusion

Differences were seen across different implants in revision rates, certain complications, and functional scores. This study highlighted that these devices should be evaluated within the context of the patient population under examination, as patients with Essex-Lopresti or terrible-triad injuries may demonstrate worse outcomes relative to those with a fracture only.

Why does radial head arthroplasty fail today? A systematic review of recent literature

Since the introduction of the radial head prosthesis (RHP) in 1941, many designs have been introduced. It is not clear whether prosthesis design parameters are related to early failure. The aim of this systematic review is to report on failure modes and to explore the association between implant design and early failure.A search was conducted to identify studies reporting on failed primary RHP. The results are clustered per type of RHP based on: material, fixation technique, modularity, and polarity. Chi-square tests are used to compare reasons for failure between the groups.Thirty-four articles are included involving 152 failed radial head arthroplasties (RHAs) in 152 patients. Eighteen different types of RHPs have been used.The most frequent reasons for revision surgery after RHA are (aseptic) loosening (30%), elbow stiffness (20%) and/or persisting pain (17%). Failure occurs after an average of 34 months (range, 0-348 months; median, 14 months).Press-fit prostheses fail at a higher ratio because of symptomatic loosening than intentionally loose-fit prostheses and prostheses that are fixed with an expandable stem (p < 0.01).Because of the many different types of RHP used to date and the limited numbers and evidence on early failure of RHA, the current data provide no evidence for a specific RHP design. Cite this article: EFORT Open Rev 2019;4:659-667. DOI: 10.1302/2058-5241.4.180099.

Preserving the radial head in comminuted Mason type III fractures without fixation to the radial shaft: a mid-term clinical and radiographic follow-up study

BACKGROUND

The treatment of multifragment Mason type III fractures is challenging. Open reduction-internal fixation (ORIF), radial head arthroplasty, and in some cases, even radial head resection are the current options; however, each of these treatment methods is associated with characteristic benefits and complications. We present our experience with a radial head salvage procedure in comminuted radial head fractures irrespective of concomitant injuries, which are not accompanied by typical ORIF-related complications.

METHODS

The first group comprised 29 patients with multifragment Mason type III fractures treated surgically with biological radial head spacers (group S). The fragments were reduced and fixated in an extracorporeal manner, and the reconstructed radial head was placed in its anatomic position without fixation to the shaft. The second group comprised 12 patients treated with conventional ORIF using mini-fragment plates (group P).

RESULTS

Thirty patients were enrolled to undergo clinical and radiographic follow-up at an average of 76 months (range, 12-152 months). In group S, nonunion at the head-neck junction developed in 70% of the cases; however, the overall Mayo Elbow Performance Index averaged 94.8, which was superior to the average Mayo Elbow Performance Index of 83.1 in group P. Radiographic evaluation showed development of osteoarthritic changes in 75% of patients in group S and 62.5% in group P. None of the patients had wrist-joint pain.

CONCLUSIONS

Preserving the native radial head in comminuted Mason type III fractures without fixation to the radial shaft is a reliable option. Excellent functional results can be expected; however, the development of osteoarthritis cannot be impeded.

Evaluation of MoPyC-prosthesis implantation and the use of angular stable plates in the treatment of comminuted radial head fractures

Objective

Comminuted radial head fractures are disproportionately often accompanied by injuries of the bone or ligaments and can be treated in different ways.

Methods

15 patients with a comminuted radial head fracture were treated with an angular stable plate (=G1) and 8 with a MoPyC-prosthesis (=G2).

Results

G1 shows an average Morrey-score of 83,87 points. Complications occurred in 5/15 patients. Within G2 an average Morrey-score of 86 was achieved. Complications could be shown in 2/8 patients.

Conclusion

Both the treatment provides a clear individual benefit for the patients and predict promising results for the treatment of comminuted radial head fractures.

Evaluation of MoPyC-prosthesis implantation and the use of angular stable plates in the treatment of comminuted radial head fractures

Objective

Comminuted radial head fractures are disproportionately often accompanied by injuries of the bone or ligaments and can be treated in different ways.

Methods

15 patients with a comminuted radial head fracture were treated with an angular stable plate (=G1) and 8 with a MoPyC-prosthesis (=G2).

Results

G1 shows an average Morrey-score of 83,87 points. Complications occurred in 5/15 patients. Within G2 an average Morrey-score of 86 was achieved. Complications could be shown in 2/8 patients.

Conclusion

Both the treatment provides a clear individual benefit for the patients and predict promising results for the treatment of comminuted radial head fractures.

Complications after radial head arthroplasty: a comparison between short-stemmed bipolar and monopolar long-stemmed osteointegrative rigidly fixed prostheses

INTRODUCTION

To date, only a few studies have compared radial head prostheses (RHP) and their different anchoring principles. The aim of this study was to characterize concomitant injuries, necessary adjuvant procedures, complications, and radiological findings after implantation of two different types of RHP.

METHODS

Sixty-six patients with radial head fractures were treated with MoPyC (Tornier/France, 50 mm stem, monopolar) or SBI rHead prostheses (Small Bone Innovations/USA, 22-mm stem, bipolar) and followed up over 42 months (16-64 months). Primary objective was the detection of different loosening and explantation rates. In addition to the revision rate and the reasons for revision, we also used radiological findings to assess the dynamics of lysis phenomena.

RESULTS

Thirty-five patients (mean age 48 years; 22-73 years) were treated with the MoPyC, and 31 patients (mean age 47 years, 19-69 years) with the rHead prosthesis. Of these, 98% had a Mason 3 or 4 type of radial head fracture, and 94% showed concomitant injuries, which were addressed in 89% of cases by adjuvant procedures. The surgical revision rate was 20% (rHead 23%; MoPyC 18%). Significantly more of the rHead prostheses had to be explanted compared to MoPyC prostheses because of painful loosening (16% vs. 3%; p = 0.029). Predictors of subsequent loosening were significant radiolucent lines in the RHP over the first six months and an increase in width by two and a half times within the first 50 days after implantation.

CONCLUSION

Complex radial head fractures are frequent and difficult to treat. The monopolar long-stemmed prosthesis showed significantly lower rates of painful loosening and explanation rates than the bipolar short-stemmed prosthesis.

Pyrocarbon arthroplasty in acute unreconstructable radial head fractures: mid-term to long term results

BACKGROUND

The aim of this study is to describe the mid-term radiological findings appearing in patients with a pyrocarbon radial head prosthesis, and to correlate them to patient symptoms.

MATERIALS AND METHODS

We review 18 patients who underwent radial head implantation of the MoPyC prosthesis between 2004 and 2015, due to unreconstructible radial head fractures. The clinical outcomes were assessed with Mayo Elbow Performance Score (MEPS). Range of motion, pain, and elbow radiological assessments were recorded. A non-parametric, statistical analysis was carried out to assess the radiological findings with the clinical outcomes.

RESULTS

We have found that after a mean follow-up of 6.5 years (2-11 years), patients have recovered a median flexion arch of 113°, therefore 77% are classed as satisfactory outcomes and the average MEPS score is 89.5. The presence of periprosthetic changes on X-ray is highly frequent-we found radiolucent lines in 38% of cases, radial neck re-absorption in 83%, and arthrosic changes in 78%. However, the differences found when correlating these changes with the clinical results have not been statistically significant (p > 0.05).

CONCLUSIONS

Satisfactory outcomes can be expected midterm when using pyrocarbon prostheses in around 75% of the cases. We consider radial neck re-absorption to be a sign of good stem osteointegration, whereas progressive radiolucencies and loss of the ballooning of the stem legs are signs of bad prognosis in our series.

LEVEL OF EVIDENCE

IV retrospective case series.

Short to midterm outcomes of one hundred and seventy one MoPyC radial head prostheses: meta-analysis

BACKGROUND

The MoPyC implant is an uncemented long-stemmed radial head prosthesis that obtains primary press-fit fixation via controlled expansion of the stem. Current literature regarding MoPyC implants appears promising; however, sample sizes in these studies are small. Our primary objective was to evaluate the short- to midterm clinical outcomes of a large sample of the MoPyC prostheses. The secondary objective was to determine the reasons for failure of the MoPyC devices.

METHODS

Four electronic databases were queried for literature published between January 2000 and March 2017. Articles describing clinical and radiographic outcomes as well as reasons for reoperation were included. A meta-analysis was performed to obtain range of motion, mean Mayo Elbow Performance score (MEPS), radiographic outcome, and reason for failure.

RESULTS

A total of five articles describing 171 patients (82 males) with MoPyC implants were included. Mean patient age and follow-up were 52 years (18-79) and 3.1 years (1-9), respectively. Midterm clinical results were good or excellent (MEPS > 74) in 157 patients. Overall complication rate was low (n = 22), while periprosthetic osteolysis was reported in 78 patients. Nineteen patients returned to the operating room, with implant revision being required in ten patients. The two primary reasons for failure were (intra-)prosthetic dislocation (n = 8) followed by stiffness (n = 7); no painful loosening was described.

CONCLUSION

Short- to midterm outcomes of MoPyC prostheses are satisfactory and complications associated are low. The use of stem auto-expansion as a mode of obtaining primary fixation in radial head arthroplasty appears to be an effective solution for reducing the risk of painful loosening.

Radial Head Resection versus Arthroplasty in Unrepairable Comminuted Fractures Mason Type III and Type IV: A Systematic Review

Unrepairable comminuted fractures of the radial head Mason type III or type IV have poor outcomes when treated by open reduction and internal fixation. Radial head resection has been proposed as good option for surgical treatment, while in the last decades, the development of technology and design in radial head prosthesis has increased efficacy in prosthetic replacement. The present review was conducted to determine the best surgical treatment for comminuted radial head when ORIF is not possible. Better outcomes are reported for radial head arthroplasty in terms of elbow stability, range of motion, pain, and fewer complications compared to radial head excision. Nevertheless, radial head resection still can be considered an option of treatment in isolated radial head fractures with no associated ligament injuries lesion of ligaments or in case of older patients with low demanding function.

Clinical and Radiographic Outcomes of Unipolar and Bipolar Radial Head Prosthesis in Patients with Radial Head Fracture: A Systemic Review and Meta-Analysis

PURPOSE

To compare clinical outcomes of unipolar and bipolar radial head prosthesis in the treatment of patients with radial head fracture.

MATERIALS AND METHODS

Medline, Cochrane, EMBASE, Google Scholar databases were searched until April 18, 2016 using the following search terms: radial head fracture, elbow fracture, radial head arthroplasty, implants, prosthesis, unipolar, bipolar, cemented, and press-fit. Randomized controlled trials, retrospective, and cohort studies were included.

RESULTS

The Mayo elbow performance score (MEPS), disabilities of the arm, shoulder, and hand (DASH) score, radiologic assessment, ROM, and grip strength following elbow replacement were similar between prosthetic devices. The pooled mean excellent/good ranking of MEPS was 0.78 for unipolar and 0.73 for bipolar radial head arthroplasty, and the pooled mean MEPS was 86.9 and 79.9, respectively. DASH scores for unipolar and bipolar prosthesis were 19.0 and 16.3, respectively. Range of motion outcomes were similar between groups, with both groups have comparable risk of flexion arc, flexion, extension deficit, rotation arc, pronation, and supination (p values <0.001 for both unipolar and bipolar prosthesis). However, bipolar radial head prosthesis was associated with an increased chance of heterotopic ossification and lucency (p values ≤0.049) while unipolar prosthesis was not (p values ≥0.088). Both groups had risk for development of capitellar osteopenia or erosion/wear (p values ≤0.039).

CONCLUSION

Unipolar and bipolar radial head prostheses were similar with respect to clinical outcomes. Additional comparative studies are necessary to further compare different radial head prostheses used to treat radial head fracture.

The Rate of Radial Head Prosthesis Removal or Revision: A Systematic Review and Meta-Analysis

PURPOSE

We conducted a meta-analysis and systematic review with the primary objective to determine the overall incidence of radial head prosthesis removal or revision. Our secondary objectives addressed the incidence of removal or revision based on the type of prosthesis fixation (cemented, uncemented smooth stem, uncemented press-fit), material (metal, Vitallium, titanium, pyrocarbon), and design (short vs long stem and monopolar vs bipolar), and the reasons for prosthetic removal or revision.

METHODS

We included 30 studies with a total of 1,017 patients out of whom 77 prostheses were removed and 45 prostheses were revised.

RESULTS

The pooled rate of radial head prosthesis removal or revision was 10.0% (95% confidence interval, 7.3%-13.6%) with a mean follow-up of 38 months. Subgroup analysis showed that the incidence of removal/revision was lowest with the cemented fixation, longer-stem, Vitallium material, and bipolar prosthesis. More than half of the prostheses were removed/revised for excision of the heterotopic ossification (47%) and for the treatment of stiffness and limitation of motion (42%). Other reasons recorded were pain (19%), loosening (16%), overstuffing (13%), instability (12%), infection (8%), and prosthesis disassembly (4%).

CONCLUSIONS

The current data show that the highest incidence of removal/revision occurred within 2 years after implantation. There was no major difference in the incidence of removal/revision among different designs and materials. Implant removal was often performed as part of a procedure to manage elbow stiffness and heterotopic ossification at the surgeon's preference, not necessarily because the implant was malfunctioning. It appears that most radial head arthroplasties have an acceptable and comparable mid-term longevity; however, it is unclear whether long-term longevity will differ between devices.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

The minimum follow-up required for radial head arthroplasty: a meta-analysis

AIMS

The primary aim of this study was to define the standard minimum follow-up required to produce a reliable estimate of the rate of re-operation after radial head arthroplasty (RHA). The secondary objective was to define the leading reasons for re-operation.

MATERIALS AND METHODS

Four electronic databases, between January 2000 and March 2017 were searched. Articles reporting reasons for re-operation (Group I) and results (Group II) after RHA were included. In Group I, a meta-analysis was performed to obtain the standard minimum follow-up, the mean time to re-operation and the reason for failure. In Group II, the minimum follow-up for each study was compared with the standard minimum follow-up.

RESULTS

A total of 40 studies were analysed: three were Group I and included 80 implants and 37 were Group II and included 1192 implants. In Group I, the mean time to re-operation was 1.37 years (0 to 11.25), the standard minimum follow-up was 3.25 years; painful loosening was the main indication for re-operation. In Group II, 33 Group II articles (89.2%) reported a minimum follow-up of < 3.25 years.

CONCLUSION

The literature does not provide a reliable estimate of the rate of re-operation after RHA. The reproducibility of results would be improved by using a minimum follow-up of three years combined with a consensus of the definition of the reasons for failure after RHA. Cite this article: Bone Joint J 2017;99-B:1561-70.

Rare implant-specific complications of the MoPyC radial head prosthesis

BACKGROUND

According to currently available data, the clinical short-term results of the MoPyC radial head prosthesis (Bioprofile, Tornier, Montbonnot-Saint-Martin, France) seem favorable. However, we have encountered several implant-specific complications in recent years. Hence, this case series reports rare complications after radial head arthroplasty with the MoPyC prosthesis to make surgeons aware of their existence and to provide information about the underlying cause and possible salvage strategies.

METHODS

A retrospective chart review from 2011 to 2016 was conducted to identify all adult patients with a minimum 2-year follow-up who underwent or were referred after radial head arthroplasty with the MoPyC radial head prosthesis and experienced implant-related complications.

RESULTS

Five patients with 7 implant-related complications were found. One patient experienced breakage of the pyrocarbon head. In another patient, breakage of the stem and-after revision surgery-partial breakage were observed. Disassembly of the prosthesis was seen in 1 case. Extensive periprosthetic stress shielding was seen in 3 patients resulting in symptomatic loosening (1), periprosthetic radial neck fracture (1), and stem migration (1).

CONCLUSIONS

Whereas clinical short-term results of the MoPyC radial head prosthesis are satisfactory, rare implant-related complications can occur. Surgeons should be aware of these complications as they may lead to a poor outcome.

Mason type III radial head fractures treated by anatomic radial head arthroplasty: Is this a safe treatment option?

BACKGROUND

Radial head fractures make up approximately 3% of all fractures and they are the most common elbow fracture in adults. Replacement through arthroplasty is the recommended treatment in the context of unstable elbow injury and comminuted radial head fracture. The midterm clinical, functional, and radiographic results in patients treated with anatomic radial head arthroplasty for a Mason type III radial head fracture are presented.

MATERIAL AND METHODS

We performed a retrospective search of our facility's prospective trauma database to identify all skeletally mature patients who were treated by primary radial head replacement or open reduction and internal fixation following an acute radial head fracture. Inclusion criteria were Mason type III fractures and anatomic radial head arthroplasty (RHA). All the patients included were evaluated using a standard postoperative protocol including clinical and radiographic evaluation at 1, 3 and 12 months of follow-up. All the patients were reviewed clinically at an average of 30 months' follow-up.

RESULTS

Forty-one subjects (32 Mason type III and 9 Mason IV fractures) were treated with anatomic RHA (Acumed, Hillsboro, OR, USA). Of these, two patients (1 Mason type III and 1 Mason type IV) were excluded from the analysis because severe cognitive impairment. Moreover, we decided to exclude the subjects with a Mason type IV fracture to obtain a more homogeneous sample. Therefore, 31 patients with a Mason type III fracture were included in this study. Based on the Mayo Elbow Performance Score, excellent results were obtained in 24 (77%) patients, good in 3 (10%) and fair in 4 (13%) patients. Heterotopic ossification was reported in 8 patients (26% of cases). The final elbow flexion-extension range of motion was of 112°, with a mean flexion of 125°. The final forearm rotational range of motion was 134° with a mean pronation of 68° and a mean supination of 66°.

DISCUSSION

Anatomic radial head replacement leads to a good functional recovery, even in the presence of severe instability, such as coronoid fractures and LUCL injury. However, patients should be informed of the high number of adverse events (mainly heterotopic ossification) following this treatment.

LEVEL OF EVIDENCE

Therapeutic IV.

[Primary radial head arthroplasty in trauma : Complications]

Radial head fractures are common injuries in elbow trauma. Non-displaced fractures are best treated conservatively. Simple but displaced fractures require anatomic reduction and fixation, typically using screws. The treatment course for complex fractures with multiple fragments is still being debated, as results are less predictable. Radial head resection is not advised if concomitant injuries of the coronoid process or the collateral ligaments with instability are present. Favorable outcomes following open reduction and fixation using plates were reported recently. However, complication rates are very high. Radial head replacement is a valuable tool in treating complex fractures of the radial head with predominantly good and excellent results. Patients who suffer radial head fractures are typically of a younger age, resulting in high functional demands. Certainly, unspecific and specific complications related to radial head arthroplasty were reported in up to 40 % of cases in an acute fracture setting. This article highlights common complications in radial head arthroplasty and aims to present strategies to avoid them.

Porous metals and alternate bearing surfaces in shoulder arthroplasty

Total shoulder arthroplasty (TSA) provides an effective solution for the treatment of glenohumeral arthritis. However, long-term outcomes have been limited by glenoid component aseptic loosening and polyethylene (PE) wear. Previous attempts to improve glenoid fixation with metal-backed glenoids resulted in inferior results. Newer component designs that contain porous metal allow for biological ingrowth of the prosthesis, potentially improving longevity and overall outcomes. Porous metal can also improve humeral component fixation, obviating the need for cement and simplifying revision surgery. Advances such as highly cross-linked polyethylene (HXLPE), vitamin E-doped HXLPE, and alternate bearing surfaces like ceramics and pyrolytic carbon have proven to provide superior wear characteristics in other joint replacements and may prove beneficial in the shoulder as well.

Radial head replacement in adults with recent fractures

Radial head fractures are fairly common (20% of all traumatic elbow injuries). Non-operative treatment is indicated in non-displaced fractures, and direct stable internal fixation allowing early elbow mobilisation in most other cases. For severely comminuted fractures precluding stable fixation, replacement of the radial head was introduced in the 1970s as a better alternative to simple radial head resection, which can induce instability of the elbow and/or forearm, most notably in patients who have complex fractures with concomitant lesions to other structures. With contemporary implants (modular or monoblock, with or without a mobile cup), mechanical stability is close to that provided by the native radial head, although appropriate treatment of concomitant lesions remains crucial (e.g., re-attachment of the radial collateral ligament, or distal radio-ulnar stabilisation in patients with Essex-Lopresti fracture). The key technical points are selection of implant size and determination of the optimal implantation height. The two most common complications are capitellar overloading due to excessively high implantation of the prosthetic head, which causes stiffness and pain, and loosening of the stem. These complications may require removal of the implant at a distance from the injury. Studies have demonstrated satisfactory clinical outcomes in 60% to 80% of cases.

Clinical and radiologic outcomes of pyrocarbon radial head prosthesis: midterm results

BACKGROUND

The modular pyrocarbon (MoPyC) radial head prosthesis (Tornier, Saint-Ismier, France) is a monoblock modular radial head prosthesis. This study assessed midterm outcomes after implantation of the prosthesis.

MATERIALS

A retrospective study was conducted of a consecutive cohort of 65 patients who underwent radial head replacement with the MoPyC prosthesis from January 2006 to April 2013. Indications were fractures, early or late failures from orthopedic or fixation treatments, and revisions after another implant. Patients were observed for >2 years for range of motion, pain, and stability; function by the Mayo Elbow Performance Score (total score, 100) and grip strength were assessed. Quality of stem implantation, bone resorption around the neck, and periprosthetic lucency were noted and quantified on radiographs. Capitellum shape and density as well as humeroulnar aspect (river delta sign) were evaluated. Complications and revision procedures were noted.

RESULTS

We evaluated 52 of 65 patients (mean follow-up, 46 ± 20 months; range, 24-108). The Mayo Elbow Performance Score was 96 ± 7; pain score, 42 ± 7/45; and motion score, 18 ± 2/20. Function and stability were excellent. Radiology revealed 92% of patients with cortical resorption around the neck without mechanical failure. Bone resorption was mostly anterior and lateral; it resolved within the first year and thereafter was stable. Eight patients underwent revision surgery for stiffness. No implant failures were noted.

CONCLUSION

Results of the MoPyC radial head prosthesis appear to be satisfactory. Bone resorption around the neck (stress shielding) is frequent and stable after 1 year and does not impair stem fixation. The MoPyC prosthesis appears to be a reliable solution for replacing the radial head.

Complications of radial head prostheses

Radial head prostheses are indicated for treatment of complex radial head fractures not amenable for fixation. After the initial experience with silastic implants, metallic or pyrocarbon arthroplasty have been used for 20 years. Little is known about complications related to these implants. Main complications are related to loosening whether they are cemented or not cemented. Hypotheses have been proposed like inadequate stem design, insufficient cement technique, stress shielding, and foreign body reactions secondary to polyethylene wear. Pain and stiffness are other common complications often related to oversized radial head component or overstuffing of the joint with excessive lengthening of the radius. Instability can be another complication in the context of more complex trauma with lateral collateral ligament complex lesion and coronoid fracture. Fixation of the coronoid fracture, reinsertion of the lateral collateral ligament complex, and the use of monobloc radial head prosthesis are recommended to stabilize the joint. Finally, osteoarthritis is common with follow-up.

Radial head replacement with pyrocarbon prosthesis: early clinical results

BACKGROUND

Comminuted radial head fractures are challenging to treat with open reduction and internal fixation. Radial head arthroplasty is a favourable technique for the treatment of complex radial head fractures. The purpose of this study was to evaluate the functional and radiological outcomes of radial head arthroplasty using modular pyrocarbon radial head prosthesis.

METHODS

We retrospectively reviewed 21 consecutive patients requiring radial head arthroplasty for unreconstructible radial head fractures between July 2003 and July 2009. Patients completed a Short Form-36 (SF-36), the Disabilities of the Arm, Shoulder and Hand questionnaire, and the Mayo Elbow Performance Index. Patients were independently physically examined and their post-operative radiographs were reviewed.

RESULTS

Twenty-one patients (nine males and 12 females) were reviewed at a minimum of 12 months follow-up. The mean Disabilities of the Arm, Shoulder and Hand score was 10.8 (0-34.1), mean SF-36 physical score was 76.9 (35-96), mean SF-36 mental score was 83.8 (60-94), and their Mayo Elbow Performance Index score was 86.4 (70-100). Patients maintained 90% of their grip strength when compared with their uninjured arm and had 17.5° of fixed flexion in the affected arm. Radiologically, 14 cases had some degree of post-traumatic osteoarthritis, 12 cases had evidence of heterotrophic ossification, five had some evidence of periprosthetic lucency and three patients were radiologically, but not functionally 'overstuffed'.

CONCLUSION

Radial head arthroplasty with pyrocarbon radial head prosthesis is an acceptable option when treating unreconstructable radial head fractures yielding good functional and radiological outcomes.

Outcomes of bipolar radial head prosthesis to treat complex radial head fractures in 22 patients with a mean follow-up of 50 months

BACKGROUND

Radial head replacement is indicated to treat complex proximal radial fractures that are not amenable to internal fixation.

HYPOTHESIS

Implantation of a bipolar radial head prosthesis after radial head excision ensures stability of the elbow and forearm, thereby promoting ligament healing and restoring elbow function.

MATERIAL AND METHODS

Twenty-two patients managed with implantation of a bipolar radial head prosthesis (Guepar(®)) were evaluated after a mean follow-up of 50 months. The procedure was performed in the acute setting in 16 patients, including 13 with associated injuries; and at the stage of sequelae in 6 patients.

RESULTS

Prosthesis removal was required in 4 patients. Of the remaining 18 patients, 14 (77%) had satisfactory Mayo Elbow Performance Score values, 14 (77%) little or no functional impairment, and 11 (61%) little or no pain. Mean motion arcs were 100° in flexion-extension and 143° in pronation-supination. Mean elbow strength in flexion and mean wrist strength were 67% and 86%, respectively, of those on the contralateral normal side. Radio-lucent lines were visible around the prosthesis in 5 patients, radial neck osteolysis in 10 patients, and capitellar erosion in 7 patients. Seven patients each experienced a complication. Early revision surgery to treat elbow instability was required in 6 patients.

DISCUSSION

Outcomes after Guepar(®) bipolar radial head prosthesis implantation were disappointing in patients with complex radial head fractures seen in the acute or chronic setting. The associated injuries to bones and ligaments and the measures taken to repair them influence the prognosis. The complication rate is non-negligible and seems to increase over time.

LEVEL OF EVIDENCE

IV, retrospective study.

[Endoprosthetics of acute radial head fractures]

Radial head arthroplasty is the treatment of choice for non-reconstructble radial head fractures. Solid prostheses made of metal or pyocarbon can restore valgus stability of the elbow independent of design or stem fixation. Short-term and mid-term results show mostly good to excellent results without any evident differences between the different prosthesis philosophies. In order to obtain good results it is important to implant the prosthesis correctly without overfilling and to judge concomitant ligament injuries correctly. This article discusses the anatomical and biomechanical basis of radial head arthroplasty as well as the surgical technique and radiological diagnosis of overfilling.

Monobloc radial head prostheses in complex elbow injuries: results after primary and secondary implantation

PURPOSE

Dislocations of components, loosening of the stem, overstuffing and removal in up to 24 % of common radial head prostheses (RHP) after implantation in complex elbow injuries signal the need for improvement. The latest biomechanical evidence shows advantages for monopolar designs. Clinical results after primary and secondary implantation of the newly designed press-fit monobloc monopolar RHP in cases of complex elbow injury are evaluated.

METHODS

Twenty-nine patients [median age 60 years (29-86)] were followed up retrospectively for a median of 25 months (7-54) post-operatively. Subjective parameters, the Mayo Elbow Performance Score (MEPS), the Broberg and Morrey score (BMS), latest radiographs and complications were evaluated.

RESULTS

MEPS and BMS averaged 87.2 ± 12.9 and 81.1 ± 11.9 points, respectively. No case of implant loosening was observed; the RHP had to be removed in one case (3 %). The overall complication and revision rate was higher after secondary (53 %) than after primary (19 %) implantation.

CONCLUSIONS

Satisfactory clinical results and low short-term removal rates emphasise the practicality of monobloc monopolar RHP. Differentiated treatment of complex elbow fracture-dislocations is compulsory to avoid the need for secondary RHP implantation which carries a higher complication rate.

Computer-aided analysis of radial head morphometry

Operative treatment of displaced and comminuted radial head fractures involves internal fixation with plates and screws in cases where reconstruction is possible and replacement with a radial head prosthesis when comminution renders the radial head unreconstructable. The purposes of this study were to evaluate the morphometry of the radial head using a modern technique and to compare the findings with several commercially available radial head prostheses. Computed tomography scans of 30 cadaveric elbows and 3-dimensional reconstructions were used to analyze the morphometry of the proximal radius. Results were compared with the manufacturer data of several radial head prostheses. Mean diameter of the radial head at the level of the fovea was 19±1.58 mm (range, 15.82-21.81 mm) in the anteroposterior plane and 18.62±1.78 mm (range, 15.48-22.21 mm) in the radioulnar plane. Mean diameter of the radial head at its widest part was 23.15±1.94 mm (range, 19.45-26.49 mm) in the anteroposterior plane and 22.44±1.73 mm (range, 19.64-25.44 mm) in the radioulnar plane. Mean diameter of the radial head at the level of the head-neck junction was 15.42±1.59 mm (range, 11.80-18.46 mm) in the anteroposterior plane and 14.75±1.39 mm (range, 12.32-17.31 mm) in the radioulnar plane. Statistically significant sex differences existed in the maximum diameter of the radial head, the diameter at the level of the head-neck junction, and the length of the radial head. Currently available radial head prostheses cover the range of sizes encountered. Products with a choice of head and stem sizes in any combination are preferable. In unstable elbow fractures, correct implant size is an important factor to avoid subluxation of the radial head (Mason type IV fractures) if collateral ligaments are sufficient.

Radial head fractures

Fractures of the radial head are the most common fractures in the elbow, and they frequently have associated ligamentous, cartilaginous, or other bony injuries. Clinical assessment and radiological investigation allow for accurate diagnosis and the formulation of a management plan. Undisplaced or minimally displaced fractures with no rotational block to motion can be treated nonoperatively with excellent results expected. The minimum amount of displacement in a partial articular radial head fracture required for open reduction and internal fixation to provide a superior outcome to nonoperative management is still unknown. Medium-term data suggest that patients with comminuted radial head fractures do well with radial head replacement.