Press-fit bipolar radial head arthroplasty, midterm results

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.

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.

Revision of Failed Radial Head Arthroplasty

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The comparative performance of radial head prostheses in patients younger than and older than 50 years: a systematic review

Background

Patient age may play a role in the surgeon's decision between radial head arthroplasty (RHA) and open reduction internal fixation in radial head fracture treatment. Though large sample reports have detailed outcomes of radial head replacement for a mean age younger than 50 years, the age ranges are widely distributed. Patient outcomes are not uniform across a broad age distribution. Therefore, treatment decisions should be evaluated within the confines of a narrower age bracket. An understanding of clinical outcomes for radial head replacement in younger adults will provide value for guiding treatment decisions. We performed a systematic review comparing the clinical outcomes for radial head replacement in patients younger and older than 50 years of age. Further analysis compared outcomes between RHA performed as a primary procedure and as a secondary procedure in patients younger and older than 50 years of age.

Methods

PubMed was queried for articles which delineated individual patient data for age, surgical treatment, and appropriate outcome metrics. Articles were grouped based on patient age of under 50 and over 50 years and within those age groups, based on the arthroplasty being performed as a primary or as a secondary procedure.

Results

There were no significant differences between the under 50 and the over 50 groups for Mayo Elbow Performance Score (P = .79) and for implant revision/removal (P = .32). In the under 50 group, RHA done as a primary procedure had significantly higher (P = .001) mean Mayo Elbow Performance Score than RHA done as a secondary procedure. In the over 50 group, relative risk was 2.39 (95% confidence interval, 2.12-2.69) for implant revision/removal (P = .11) when comparing primary and secondary procedures.

Discussion

At a mean follow-up of 48 months, RHA in patients under the age of 50 years had satisfactory outcomes which were comparable to outcomes in patients over the age of 50 years. Across both age groups, arthroplasty performed as a primary procedure demonstrated superior outcomes compared to arthroplasty performed as a secondary procedure. Our findings provide guidance to surgeons who face a multifaceted decision when encountering younger adult patients with radial head fracture patterns that may not be amenable to fixation. Awareness of the age-specific performance of radial head implants is an important component of the decision for surgical treatment.

30-Day outcomes analysis of surgical management of radial head fractures comparing radial head arthroplasty to open reduction internal fixation

INTRODUCTION

Radial head arthroplasty and open reduction internal fixation are two commonly utilized treatment options for radial head fractures. The purpose of this study is to assess the incidence of and risk factors for short-term complications following radial head arthroplasty and open reduction internal fixation of radial head fractures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients that underwent radial head arthroplasty or open reduction internal fixation for radial head fractures between January 1st, 2015 and December 31st, 2017. The incidence of various 30-day complications, including unplanned readmission, reoperation, non-home discharge, mortality, surgical/medical complications, and extended length-of-stay were compared between the two propensity matched groups. Multivariate logistic regression was used to identify independent risk factors for various short-term complications.

RESULTS

After propensity matching, a total of 435 patients were included in our analysis. 250 patients underwent radial head arthroplasty, and 185 patients underwent open reduction internal fixation. Arthroplasty treated patients had a significantly longer mean total operative time (p = .031) and length-of-stay (p = .003). No significant 30-day complications differences were found for unplanned readmission, reoperation, non-home discharge, mortality, surgical complications or medical complications. Independent risk factors for any complications of both procedures included a history of chronic obstructive pulmonary disease and American Society of Anesthesiologists class III. Significant risk factors for length-of-stay greater than two days included a history of bleeding disorder and American Society of Anesthesiologists class III.

CONCLUSION

Our study revealed there were no significant differences in 30-day perioperative surgical or medical complications from either surgical treatment of radial head fractures; however, radial head arthroplasty treated patients were met with a significantly longer length-of-stay and longer duration of operating time. We also identified risk factors that were independently associated with higher rates of complications regardless of treatment type.

Long-term outcome and survival rate of monopolar radial head replacement

BACKGROUND

The purposes of this study were (1) to report functional outcomes; (2) to assess complications, revisions, and survival rate; and (3) to assess differences in functional outcomes between removed and retained radial head arthroplasties (RHAs), early and delayed treatment, and type of RHA used at long-term follow-up after monopolar RHA for unreconstructible radial head fractures or their sequelae.

METHODS

Seventy-eight patients (mean age, 59.2 years) who were at least 6 years postoperatively after monopolar RHA for unreconstructible RHFs or their sequelae were included. The Mayo Elbow Performance Score (MEPS); Quick Disability of the Arm, Shoulder, and Hand (QuickDASH) score; visual analog scale; postoperative satisfaction (1-6, 6 = highly unsatisfied); range of motion; complications; and revisions were assessed. Radiographic findings were reported. Kaplan-Meier survival analysis was performed. Subgroups (RHA type, early vs. delayed surgery, RHA removed vs. retained) were compared.

RESULTS

At a median clinical follow-up of 9.5 years (range: 6.0-28.4 years), median MEPS was 80.0 (interquartile range [IQR]: 60.0-97.5), median QuickDASH was 22.0 (IQR: 4.6-42.6), median visual analog scale was 1 (IQR: 0-4), median postoperative satisfaction was 2 (IQR: 1-3), and median arc of extension/flexion was 110° (IQR: 80°-130°). Radiographic follow-up was available for 48 patients at a median of 7.0 years (range: 2.0-15.0 years). Heterotopic ossifications were seen in 14 (29.2%), moderate-to-severe capitellar osteopenia/abrasion in 3 (6.1%), moderate-to-severe ulnohumeral degeneration in 3 (6.1%), and periprosthetic radiolucencies in 17 (35.4%) patients. Twenty-nine patients (37.2%) had complications and 20 patients (25.6%) underwent RHA exchange or removal. Kaplan-Meier analysis with failure defined as RHA exchange or removal demonstrated survival of 75.1% (95% confidence interval: 63.7-83.3) at 18 years. The highest annual failure rate was observed in the first year in which the RHAs of 7 patients (9%) were exchanged or removed. No significant differences were detected between type of RHA in MEPS (Mathys: 82.5 [75.0-100] vs. Evolve: 80.0 [60.0-95.0]; P = .341) and QuickDASH (Mathys: 12.5 [0-34.4] vs. Evolve: 26.7 [6.9-46.2]; P = .112). Early surgery (≤3 weeks) yielded significantly superior MEPS (80.0 [70.0-100.0] vs. 52.5 [30.0-83.8]; P = .014) and QuickDASH (18.6 [1.5-32.6] vs. 46.2 [31.5-75.6]; P = .002) compared with delayed surgery (>3 weeks). Patients with retained RHAs had significantly better MEPS (80.0 [67.5-100] vs. 70.0 [32.5-82.5]; P = .016) and QuickDASH (18.1 [1.7-31.9] vs. 49.1 [22.1-73.8]; P = .007) compared with patients with removed RHAs.

CONCLUSIONS

Long-term outcomes for RHA are satisfactory; however, there is a high complication and revision rate, resulting in implant survival of 75.1% at 18 years with the highest annual failure rate observed in the first postoperative year.

RADIAL head arthroplasty: does ligaments repair influence outcomes? A minimum two years follow-up radiographic multi-center study

PURPOSE

The current indication for comminuted radial head fractures is radial head arthroplasty (RHA). The main purpose of this study was to investigate any statistical differences in terms of prosthesis revision or removal and radiographic degenerative changes by comparing patients who underwent RHA and ligaments repair to those who underwent only RHA implant at minimum two years follow-up. The secondary aim was to delineate a trend profile of RHA implants.

METHODS

All patients who underwent RHA surgery for traumatic pathology between January 2012 and December 2017 were eligible. Two researchers independently and retrospectively reviewed the patients' charts and collected the following data: type of prosthesis, associated surgical procedures and revision surgery. They also looked for any radiographic sign of prosthesis loosening, overstuffing, capitellar osteopenia, heterotopic ossification and degenerative changes. No clinical evaluation was performed.

RESULTS

In 6 years, 124 RHA were implanted (74 female, 50 male, mean age 56). The main diagnoses were: terrible triad, trans-olecranon fracture and isolated radial head fracture. It was found no significant statistical difference between the 2 groups; nevertheless, the cohort of patients that underwent ligaments repair had a lower revision rate in comparison with the other. Suture of the annular ligament seems to be critical. The overall revision rate was 10.5%.

CONCLUSION

This multi-center study found no evidence that ligaments repair, as an associated surgical procedure, improves RHA longevity, except for annular ligament. Nevertheless, it seems to prevent degenerative changes at midterm follow-up.

Risk Factors for Revision Surgery Following Radial Head Arthroplasty without Cement for Unreconstructible Radial Head Fractures: Minimum 3-Year Follow-up

BACKGROUND

Revision rates following radial head arthroplasty (RHA) for unreconstructible radial head fractures (RHFs) differ vastly in the literature, and little is known about the risk factors that are associated with revision surgery. The purposes of this study were to assess the revision rate following RHA and to determine the associated risk factors.

METHODS

A total of 122 patients (mean age, 50.7 years; range, 18 to 79 years) with 123 RHAs who underwent RHA for unreconstructible RHFs between 1994 and 2014 and were ≥3 years out from surgery were included. Demographic variables, injury and procedure-related characteristics, radiographic findings, complications, and revision procedures were assessed. Cox regression analysis was performed to identify the risk factors that were associated with revision surgery following RHA.

RESULTS

The median follow-up for the study cohort was 7.3 years (interquartile range [IQR], 5.1 to 10.1 years). All of the patients had unreconstructible RHFs: Mason-Johnston type-IV injuries were the most prevalent (80 [65%]). One or more associated osseous or ligamentous injuries were seen in 89 elbows (72.4%). The median time to surgery was 7 days (IQR, 3 to 11 days). Implanted prostheses were categorized as rigidly fixed (65 [52.8%]) or loosely fixed (58 [47.2%]). A total of 28 elbows (22.8%) underwent revision surgery at a median of 1.1 years (IQR, 0.3 to 3.8 years), with the majority of elbows (17 [60.7%]) undergoing revision surgery within the first 2 years. The most common reason for revision surgery was painful implant loosening (14 [29.2% of 48 complications]). Univariate Cox regression suggested that Workers' Compensation claims (hazard ratio [HR], 5.48; p < 0.001) and the use of an external fixator (HR, 4.67; p = 0.007) were significantly associated with revision surgery.

CONCLUSIONS

Revision rates following RHA for unreconstructible RHFs are high; the most common cause for revision surgery is painful implant loosening. Revision surgeries are predominantly performed within the first 2 years after implantation, and surgeons should be aware that Workers' Compensation claims and the use of an external fixator in management of the elbow injury are associated with revision surgery.

LEVEL OF EVIDENCE

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

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.

Acute radial head replacement with bipolar prostheses: midterm results

In irreparable radial head fractures, especially if primary stabilizers of the elbow are damaged, the prosthetic replacement prevents instability and stiffness. Concerns have arisen over the use of bipolar press-fit prostheses due to the frequent finding of osteolysis and the risk of instability if compared to monopolar implants. Our aim was to assess midterm clinical and radiological outcomes of bipolar implants and the influence of osteolysis on proximal pain. Seventeen patients with irreparable fractures of the radial head, treated in acute with the same prosthetic model (rHEAD recon SBI/Stryker) between January 2015 and December 2018, were enrolled. Clinical assessment was performed using MEPS and DASH scores; a radiographic study was done to identify heterotopic ossifications and periprosthetic osteolysis. Outcomes at the last follow-up, according to MEPS, were excellent in 10 cases, good in 5 and fair in 2; none of the patients had severe pain or instability. In 3 cases, it was necessary to remove the implant, mainly because of early loosening. Radiological findings of osteolysis were detected in 9 cases, but no statistical correlation was found with MEPS and proximal pain. The use of bipolar implants is reliable if an accurate repair of ligament tears is performed and provides a good stability. Nevertheless, the risk of early aseptic loosening in uncemented implants is not negligible, and the follow-up of the patient must be strict. Late osteolysis does not seem to have clinical relevance, but further prospective studies are necessary to clarify this topic.

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

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.

Indications and Clinical Results of Radial Head Replacement: Has Anything Changed?

Radial head fractures are common injuries comprising 1/3 of the fractures about the elbow. As a secondary valgus stabilizer of the elbow, radial head fractures can compromise elbow stability leading to long-term pain, dysfunction, and degenerative change. Furthermore, radial head fractures can be accompanied by associated injuries including ligamentous lesions that can further exacerbate elbow instability, leading to long-term sequelae. As fixation principles and technology have evolved, so has the ability to render surgical treatment for these fractures. In general, minimally displaced and some displaced fractures may be treated nonoperatively with early motion. Fractures with a block to rotation and displaced fragments with 3 or fewer fragments may be treated with open reduction and internal fixation. Comminuted fractures or those with greater than 3 fragments may be successfully treated with radial head replacement. Associated elbow instability will also influence treatment decisions.

Computed Tomography Analysis of the Radial Notch of the Ulna

PURPOSE

The anatomy of the radial head and capitellum has been extensively studied; however, the anatomy of the radial notch of the ulna (RNU) has received little attention. This imaging-based anatomic study characterizes the morphology of the RNU.

METHODS

Ninety-eight cadaveric arms (57 male, 72 ± 14 y) were imaged with computed tomography, and 3-dimensional reconstructions of the proximal ulna were constructed. The anteroposterior and proximal-distal dimensions of the RNU as well as the radius of curvature at standardized levels were measured in 2-mm increments. The orientation of the RNU was also determined.

RESULTS

The proximal-distal and anteroposterior dimensions of the RNU were 12 ± 2 mm (range, 7-16 mm) and 18 ± 3 mm (range, 12-24 mm), respectively. The average radius of curvature of the RNU was 15 ± 0 mm (range, 15-16 mm). The radius of curvature did not change significantly when comparing the proximal and distal aspect of the RNU. The RNU was rotated 33° ± 2° (range, 31° to 38°) externally relative to the transverse plane of the ulna. The average depth of the RNU at its deepest point was 2.2 ± 0.4 mm (range, 1.5-2.7 mm). The depth decreased from proximal to distal, being most shallow distally. The depth changed by an increase of the radius of curvature, as well as by rotation in the frontal plane.

CONCLUSIONS

The RNU anatomy was variable, generally extending laterally from proximal to distal. This suggests that a radial head implant should taper from proximal to distal to optimize contact at the RNU.

CLINICAL RELEVANCE

The present study investigates the detailed anatomy of the radial notch of the ulna using computed tomography scans. The data might help improve the design of prosthetic components.

Comparison of the biomechanics of radial head prostheses with dynamic loading in the radiocapitellar joint

We used eight fresh cadaveric elbows to evaluate the biomechanical characteristics of the native radial head, an anatomic radial head prosthesis, and a non-anatomic radial head prosthesis using a dynamic model. The biceps, brachialis, and triceps were attached to pneumatic actuators loaded to mimic muscle force. The radiocapitellar contact pressure and area were measured in real time, and the associated curves were depicted simultaneously. No significant differences in the contact area or associated curves were found between native radial head and the anatomic radial head prosthesis. The contact pressure and associated curve for the anatomic radial head prosthesis were better than those for the non-anatomic radial head prosthesis. We conclude from this study that the contact pressure and area of the elbow with anatomic radial head prosthesis are similar to those of the native radial head. The anatomic radial head prosthesis appears to be more suitable in clinical use.

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.

Morphometry of the radiocapitellar joint: is humeral condyle diameter a reliable predictor of the size of the radial head prosthesis?

BACKGROUND AND HYPOTHESIS

Radial head arthroplasty (RHA) is a reliable procedure to manage complex injuries of the elbow, but complications due to inadequate sizing have been observed. Radiocapitellar morphometry has been studied widely, but RHA preoperative planning is not yet well defined. We hypothesized that specific morphologic parameters of the radiocapitellar joint measured with simple clinical software for radiographic analysis could be useful tools for clinical practice to predict RHA size preoperatively.

METHODS

Radiologic radiocapitellar joint dimensions (humeral condyle diameter [HCDi], radial head diameter [RHDi], and radial head height) were analyzed on true anteroposterior and lateral radiographs, using commercial picture archiving and communication system software, in 43 patients with non-osseous pathology of the elbow and 24 patients with RHA. Interobserver concordance was studied, and a regression model to relate different parameters was developed.

RESULTS

Interobserver concordance was greater than 0.8 for HCDi and RHDi on the lateral view and RHDi on the anteroposterior view for the general population. The parameter with the best correlation with the radial head arthroplasty diameter (RHADi) size was HCDi on the lateral view. A regression model was calculated and defined as follows: RHADi = 6.99 + 0.733 × HCDi on lateral view. This model allows prediction of RHADi in 67% of cases.

CONCLUSION

Radiologic radiocapitellar parameters show good interobserver reliability. RHADi can be calculated preoperatively from HCDi on the lateral view in 67% of cases.

Interobserver reliability of radiographic assessment after radial head arthroplasty

BACKGROUND

Radiographs are part of routine clinical care after radial head arthroplasty (RHA). Therefore, the aim of this diagnostic study was to assess the interobserver reliability of radiographic assessment following RHA.

METHODS

Anteroposterior (AP) and lateral radiographs of 24 consecutive patients who underwent press-fit bipolar RHA were evaluated with respect to 14 parameters by 14 orthopaedic surgeons specializing in the elbow: shaft loosening (AP, lateral), subcollar bone resorption, nonbridging heterotopic ossification, capitellar erosion, capitellar osteopenia, implant size, ulnohumeral joint gapping, ulnohumeral joint degeneration, proximal radio-ulnar joint congruency, stem size, stem positioning (AP, lateral) and component dissociation or polyethylene wear of the head with increased angulation. Observer agreement was evaluated using the multirater kappa (κ) measure.

RESULTS

Nine of 14 parameters had poor interobserver agreement [κ = 0.0 to 0.20, confidence interval (CI) = 0.0 to 0.31). Four parameters had fair agreement: subcollar bone resorption (κ = 0.27, CI = 0.12 to 0.40), capitellar erosion (κ = 0.30, CI = 0.20 to 0.40), ulnohumeral joint degeneration (κ = 0.35, CI = 0.22 to 0.51) and stem positioning in AP view (κ = 0.24, CI = 0.14 to 0.36). One parameter had moderate agreement: nonbridging heterotopic ossification (κ = 0.47, CI = 0.31 to 0.64).

CONCLUSIONS

The overall interobserver reliability of radiographic assessment following press-fit bipolar RHA was poor among experienced elbow surgeons. Therefore, radiographic evaluation after RHA should be interpreted with caution when making treatment decisions.

Radial head replacement with a bipolar system: an average 10-year follow-up

BACKGROUND

We report the long-term results of a cohort of patients after radial head replacement with a bipolar design and a smooth cementless stem at a mean follow-up of 10.4 years.

METHODS

Of 17 possible patients from a previous minimum 2-year follow-up study, 16 were available for review. Patients were assessed using clinical and radiographic examination and with standardized outcome measures. Range of motion, stability, and radiographic evaluation of implant loosening and joint degeneration were assessed. Comparisons were performed using the Wilcoxon signed rank test for unequal groups.

RESULTS

The average follow-up was 10.5 years (range, 8.5-12 years). The median visual analog scale was 1 (range, 0-5), Minnesota Elbow Performance Index was 93 (range, 70-100), and the Disabilities of the Arm, Shoulder and Hand was 7.5 (range, 0-53). Range of motion was decreased on the operative side compared with the nonoperative side for flexion/extension (P = .005) and pronation/supination (P = .015). Grip strength was decreased on the affected side (P = .045). No patients had elbow instability. Significant arthritic changes developed in 2 patients at the ulnohumeral joint. The median cantilever quotient was 0.4 (range, 0.30-0.50). Osteolysis in zones 1 to 7 was found in all but 2 patients. The median stem radiolucency was 0.5 mm (range, 0.2-0.9 mm). No reoperations occurred since our previous report. Implant survival in this cohort was 97%.

CONCLUSION

Bipolar radial head prosthesis with a smooth cementless stem effectively restores elbow stability and function after comminuted radial head fractures with or without concomitant elbow instability. Our study demonstrates excellent long-term implant survival.

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.

Clinical and radiographic outcome of revision surgery of radial head prostheses: midterm results in 16 patients

BACKGROUND

Little is known about revision surgery of radial head arthroplasty. The aim of this study was to report on the clinical and radiographic outcome of revision arthroplasty of the elbow with a bipolar metallic radial head prosthesis.

METHODS

Between 2006 and 2013, we used either a press-fit or cemented RHS bipolar radial head prosthesis for revision surgery of radial head arthroplasty in 16 patients. Patients were prospectively enrolled in the study. Differences in outcome parameters before and after revision surgery were compared.

RESULTS

At a mean follow-up of 75 months (range, 36-116 months), none of the revised radial head prostheses needed a second revision. None of the stems showed radiographic signs of loosening. In 1 patient the head was dissociated from the prosthesis. The average flexion-extension arc was 127° (range, 105°-140°), and the average pronation-supination arc was 138° (range, 90°-160°). Stability scores improved after revision surgery, resulting in 13 stable elbows (P = .01). In 8 patients the Oxford Elbow Score was between 37 and 48 points. The percentage of patients with either good or excellent results according to the Mayo Elbow Performance Score was 63%. The mean score on the EQ-5D (EuroQol Five Dimensions) was 80 (range, 63-100), and the visual analog scale scores both for pain at rest and for pain with activity improved to 3 (range, 0-9) and 4 (range, 0-9), respectively (P < .001). All but 1 patient was satisfied with the results of the revision procedure.

CONCLUSION

The clinical and radiographic outcomes of revision surgery of a radial head prostheses are favorable.