Radial Head Fractures Treated with Modular Metallic Radial Head …jc.dalortho.ca/wp-content/uploads/2016/04/radial-head... · 2016. 4. 11. · Background: Radial head arthroplasty

A commentary by Pierre Mansat, MD, PhD,is linked to the online version of this articleat jbjs.org.

Radial Head Fractures Treated with ModularMetallic Radial Head Replacement

Outcomes at a Mean Follow-up of Eight Years

Jonathan P. Marsh, MD, FRCSC, Ruby Grewal, MD, MSc, FRCSC, Kenneth J. Faber, MD, MHPE, FRCSC,Darren S. Drosdowech, MD, FRCSC, George S. Athwal, MD, FRCSC, and Graham J.W. King, MD, MSc, FRCSC

Investigation performed at the Roth | McFarlane Hand & Upper Limb Centre, St. Joseph’s Health Centre, London, Ontario, Canada

Background: Radial head arthroplasty is commonly used to treat acute unreconstructible radial head fractures.The purpose of this study was to report on the clinical and radiographic outcomes at a minimum follow-up offive years after radial head arthroplasty with a modular metallic implant for the treatment of acute radial headfractures.

Methods: The cases of fifty-five patients with unreconstructible radial head fractures treated acutely with asmooth-stemmed modular metallic radial head implant were retrospectively reviewed. A wide variety of injuries,which ranged from isolated radial head fractures to so-called terrible triad injuries, were included. All patientsreturned for an interview, physical examination, and radiographic evaluation at a mean of eight years (range, five tofourteen years) postoperatively. Elbow and forearm motion, elbow strength, and grip strength were measured.Radiographs were evaluated, and validated patient-rated outcome questionnaires were completed. A longitu-dinal subgroup analysis was performed for thirty-three patients who were previously evaluated at two yearspostoperatively.

Results: At a mean of 8.2 ± 2.9 years, the mean arc of flexion (and standard deviation) of the affected elbow was 11� ±14� to 137� ± 15�. Elbow strength and motion were significantly diminished compared with the unaffected elbow(p < 0.05). The mean Mayo Elbow Performance Index (MEPI) was 91 ± 13 points. Twenty-five patients (45%) had stemlucencies; twenty-one (38%), ulnohumeral arthritis; and twenty (36%), heterotopic ossification, including one with radio-ulnar synostosis. Two patients underwent secondary elbow surgery, but no patient required implant removal or revision. Inthe subgroup evaluated longitudinally, there was a significant improvement in MEPI scores from the two-year to the eight-year follow-up (p = 0.012), with no loss of motion or strength (p > 0.05).

Conclusions: The mid-term outcomes of radial head arthroplasty with a smooth-stemmed modular metallic pros-thesis are comparable with previously reported short-term outcomes, with no evidence of functional deterioration.Radial head arthroplasty with a smooth-stemmed metallic modular implant is a good treatment option for patientswith acute unreconstructible radial head fractures, and sustained clinical outcomes may be expected beyond fiveyears of follow-up.

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

Disclosure: No external source of funding was used for this study. On the Disclosure of Potential Conflicts of Interest forms, which are provided with theonline version of the article, one of the authors checked “yes” to indicate that he had a relevant financial relationship in the biomedical arena outside thesubmitted work, including a relationship with the manufacturer of the device that is the subject of this article, and “yes” to indicate that the author had apatent for the device that is the subject of this article.

Peer review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. The Deputy Editorreviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one ormore exchanges between the author(s) and copyeditors.

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COPYRIGHT � 2016 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED

J Bone Joint Surg Am. 2016;98:527-35 d http://dx.doi.org/10.2106/JBJS.15.00128

The indications for surgical treatment of radial head frac-tures include articular displacement, a mechanical blockto motion, and unstable fractures associated with other

osseous or ligamentous injuries about the elbow1. The surgicaltreatment options include open reduction and internal fixation,radial head resection, or radial head arthroplasty.

Although numerous studies have described the outcomesof radial head fractures treated with metallic radial head replace-ments, most are smaller series with limited follow-up2-8. Theoutcomes of treatment with a smooth-stemmed, monoblock ti-tanium radial head replacement, at a mean of twelve years, werereported by Harrington et al. in 20012. Since that time, importantadvances have been made in implant sizing, surgical technique,and our understanding of elbow biomechanics. Short-term out-comes after radial head arthroplasty with a smooth-stemmedmodular metallic radial head prosthesis for the treatment of acuteradial head fractures were reported in 2006 by Grewal et al.3. Thepurpose of the present study was to evaluate the clinical and ra-diographic outcomes at a minimum follow-up of five years afterradial head arthroplasty with a smooth-stemmedmodularmetallicprosthesis for the treatment of acute radial head fractures.

Materials and Methods

Theoperative database at our institutionwas reviewed to identify all patientswho had acute radial head fractures treated with radial head arthroplasty

between 2000 and 2008. Sixty-nine comminuted radial head fractures in sixty-nine consecutive patients were treated by five fellowship-trained elbow surgeons.All fractures were deemed unreconstructible on the basis of preoperative imagingand intraoperative findings. All patients were treated with a modular smooth-stemmed radial head implant (Evolve; Wright Medical Technology).

To be included in the study, the patients must have been skeletally matureand had an acute radial head fracture treated primarily with radial head arthroplasty.Patients with open injuries, work-related injuries, and simultaneous ipsilateralupper extremity injuries were included in the study. Exclusion criteria were treat-ment after four weeks from the time of injury and previous ipsilateral elbow surgery.

Approval fromour institution’s human research ethics boardwas obtained,and each patient provided written informed consent prior to enrollment in thestudy. All sixty-nine patients who were eligible to participate in the study werecontacted by telephone. One patient declined participation, two patients weredeceased, and eleven were lost to follow-up. Fifty-five patients, who represented82% of the living cohort, returned for clinical and radiographic follow-up.

The surgical technique for radial head arthroplasty at our institutionhas been well described in previous publications

3,9-15. A detailed description

of the technique is available in the Appendix.

Outcome MeasuresThe patient charts, radiographs made at the time of injury, and operative reportswere reviewed. Each patient returned for an evaluation specifically for the purposeof this study. At that time, clinical and radiographic data for the final follow-upevaluation were collected. A separate independent observer (a physiotherapist) notinvolved in the care of the patients collected the remaining data, including validatedself-reported outcome questionnaires and objective measurements of elbow andforearm strength and range of motion.

Elbow-specific disability was measured using the Patient-Rated ElbowEvaluation (PREE)

16,17. General health was evaluated using the Short Form-12

(SF-12)18, and upper extremity disability was evaluated with the QuickDASH, an

abbreviated version of the Disabilities of the Arm, Shoulder and Hand (DASH)questionnaire

19. TheMayo ElbowPerformance Index (MEPI) was calculated using

answers to five specific questions extracted from the PREE in conjunction withobjective measurements of elbow stability and range of motion

3,20.

Elbow range of motion, including flexion, extension, supination, andpronation, was measured using a manual goniometer. Isometric strength in elbowflexion, extension, supination, and pronation, with the elbow at 90� of flexion andneutral rotation, was tested with the System 3 dynamometer (Biodex MedicalSystems). Isometric grip strengthwas tested using the Tracker FreedomWirelessGripsystem (JTECH Medical) with no correction for hand dominance.

All patients had anteroposterior and lateral radiographs of their elbowsmade with the forearm in neutral rotation. Two fellowship-trained elbow sur-geons (J.P.M. andG.S.A.) interpreted all radiographs and drew conclusions on thebasis of consensus agreement. The radiographs were evaluated for the presenceof heterotopic ossification using the Brooker classification system

21. Capitellar os-

teopeniawas graded asmild, moderate, or severe3,4. These classification systemswere

previously applied to the elbow by Grewal et al.3and Moro et al.

4. Ulnohumeral

degenerative changes were graded using the Broberg and Morrey classification sys-tem

22. Periprosthetic lucency around the stem was graded on the basis of a modi-

fication of the classification system described by Gruen et al.23, which was used in

previous studies on radial head arthroplasty3,4. Radiocapitellar alignment was eval-

uated, and parallelism of the medial ulnohumeral joint space was measured on theanteroposterior radiograph to determine if the radius had been overlengthened

10.

Statistical analysis was performed using paired t tests to compare strengthand motion measurements of the affected and the unaffected elbow (a = 0.05).

A subgroup of thirty-three patients had previously been evaluated attwo years postoperatively in the samemanner as part of a published prospectivestudy from our institution

3. It included a heterogeneous group of injuries

ranging from isolated radial head fractures to terrible triad injuries similar to

TABLE I Patient and Injury Characteristics

Characteristics No. (%) of Patients

Total 55 (100)

Sex

Male 21 (38)

Female 34 (62)

Dominant limb injured 26 (47)

Associated ipsilateral elbow injuries

Elbow dislocations 22 (40)

Olecranon fractures 3 (5)

Coronoid fractures* 38 (69)

Type 1 34 (62)

Type 2 3 (5)

Type 3 1 (2)

Distal humeral fractures 4 (7)

Open fractures 2 (4)

LUCL disruption requiring repair† 43 (78)

MUCL disruption requiring repair‡ 2 (4)

Mechanism of injury

Fall from standing height 33 (60)

Fall from height 10 (18)

Fall down stairs 6 (11)

Bicycle 4 (7)

Snowboarding 1 (2)

Motorcycle 1 (2)

*Coronoid fractures were classified according to the systemdescribed by Regan and Morrey28. †LUCL = lateral ulnar collateralligament. ‡MUCL = medial ulnar collateral ligament.

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VOLUME 98-A d NUMBER 7 d APRIL 6, 2016RADIAL HEAD FRACTURES TREATED WITH MODULAR METALL IC

RADIAL HEAD REPLACEMENT

the current larger cohort. The results at the two-year and the eight-year follow-upevaluation for these thirty-three subjects were compared, using paired t tests.

ResultsPatient and Injury Characteristics

Fifty-five patients with a mean age (and standard deviation)of 61 ± 14 years returned for follow-up at mean of 8.2 ± 2.9

years (range, five to fourteen years). At the time of injury, themean patient age was 53 ± 14 years, with amean time from injuryto surgery of 7 ± 6 days. Elbow dislocations requiring closedreduction, ligamentous injuries of the elbow requiring repair, andconcomitant elbow fractures at the time of injury are documentedin Table I. Two patients had Gustilo-Anderson24 grade-2 openolecranon fractures treated with single-stage irrigation and de-bridement, fixation of the olecranon, and radial head arthro-plasty within twenty-four hours of the injury. Two patients hadsimultaneous open reduction and internal fixation of injuries inthe ipsilateral upper extremity (a scaphoid fracture and a distalradial fracture). Two patients had a Workers’ Compensationclaim, and one patient had ongoing litigation. At the time of finalfollow-up, two patients had undergone secondary elbow surgerybut no implants had been removed or revised. A detailed de-scription of patient complications is available in the Appendix.

Patient Self-Reported OutcomesAt a mean follow-up of eight years, three patients had not com-pleted the questionnaires so the results represent the completeresponses of fifty-two patients (Table II). The SF-12 mental andphysical component scores were within the range for the normalpopulation. The mean QuickDASH and PREE scores were both14 (with 0 being the best and 100 being the worst possible scores).

The mean MEPI was 91 ± 13 points, with the outcome ratedexcellent for thirty-six patients, good for nine patients, fair for fivepatients, and poor for two patients.

TABLE II Self-Reported Outcomes Measures at a Mean Follow-up of Eight Years

Measure* Score† RangeBest/Worst

Possible Score

SF-12‡

Physical component 47 ± 11 16-61

Mental component 52 ± 10 25-64

QuickDASH 14 ± 15 0-55 0/100

MEPI

Pain 37 ± 11 7-45 45/0

Motion 20 ± 1 15-20 20/0

Stability 10 ± 0 10-10 10/0

Function 24 ± 3 8-25 25/0

Total 91 ± 13 46-100 100/0

PREE

Pain 9 ± 12 0-42 0/50

Function 14 ± 23 0-114 0/150

Total 14 ± 18 0-79 0/100

*SF-12 = Short Form-12, QuickDASH = abbreviated version of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, MEPI = MayoElbowPerformance Index, andPREE=Patient-Rated ElbowEvaluation.†The values are given as the mean and the standard deviation.‡The normalscore is 50 ± 10 for the SF-12 physical component and for the mental component.

TABLE III Radiographic Assessment at a Mean Follow-up ofEight Years

Radiographic Parameter No. (%) of Elbows

Periprosthetic lucency 25 (45)

Mild 15 (27)

Moderate 10 (18)

Severe 0

Ulnohumeral arthritis 21 (38)

Grade 1 16 (29)

Grade 2 3 (5)

Grade 3 2 (4)

Heterotopic ossification 20 (36)

Grade 1 14 (25)

Grade 2 5 (9)

Grade 3 0

Grade 4 1 (2)

Capitellar osteopenia 12 (22)

Mild 10 (18)

Moderate 1 (2)

Severe 1 (2)

Abnormal radiocapitellar alignment 1 (2)

Inappropriate implant size 0

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Strength and Range of MotionAt a mean follow-up of eight years, fifty-five patients underwentrange-of-motion evaluation and fifty-one patients underwentstrength testing (data on four patients who did not complete thestrength testing are not included) (Figs. 1 and 2). Compared withthe unaffected elbow, the affected elbow had significantly lessflexion (137� versus 141�; p < 0.001), extension (11� versus 2�;

p < 0.001), pronation (79� versus 82�; p= 0.013), and supination(67� versus 76�; p < 0.001). The mean flexion arc of motion ofthe affected elbow was 126� ± 21� (from 11� ± 14� to 137� ±15�). The affected extremity was also significantly weaker inelbow flexion (35 versus 38 Nm; p = 0.014) and extension (32versus 35 Nm; p = 0.019). There was no significant differencebetween the elbows with respect to forearm pronation (p = 0.64)or supination strength (p = 0.050) or grip strength (32 ± 13 kgversus 33 ± 12 kg; p = 0.061). The mean grip strength of theaffected limb was 97% ± 17% of that of the unaffected limb.

Radiographic AssessmentA summary of the radiographic findings is presented in Table III.At a minimum follow-up of five years, no implant had fractured,loosened, or been removed or revised. All implants were ap-propriately sized with no evidence of overlengthening of the ra-dius (Figs. 3-A and 3-B). One patient had malalignment of thearticulation between the implant and the capitellum associatedwith severe ulnohumeral arthritis and capitellar erosion (Figs.4-A through 4-F). Heterotopic ossification was observed in 36%of patients, with the majority having minor calcification withinthe collateral ligaments and capsule.

Subgroup AnalysisThe self-reported outcomemeasures at the two-year and the eight-year follow-up evaluation for the longitudinal group of thirty-threepatients are compared in Table IV. There was no significant dif-ference in SF-12 mental component (p = 0.14) or physical com-ponent scores (p = 0.46) or in the QuickDASH scores (p = 0.20)over this time period. The mean PREE pain subscale score im-proved from 13 ± 11 at two years to 10 ± 13 at eight years (p =0.032). There was significant improvement in mean MEPI scoresfrom 86 ± 12 at two years to 91 ± 12 at eight years (p = 0.012).

The objective physical outcome measures of the subgroupat two and eight years of follow-up are presented in Table V.

TABLE IV Longitudinal Comparison of Self-Reported OutcomeMeasures in a Subgroup of Thirty-three Patients at aMean Follow-up of Two Years and Eight Years

Measure* 2-Yr Follow-up† 8-Yr Follow-up†

SF-12

Physical component 44 ± 10 45 ± 12

Mental component 53 ± 11 51 ± 11

QuickDASH 19 ± 18 14 ± 14

MEPI

Pain‡ 33 ± 10 37 ± 11

Motion 19 ± 2 20 ± 1

Stability 10 ± 0 10 ± 0

Function 24 ± 3 24 ± 2

Total‡ 86 ± 12 91 ± 12

PREE

Pain‡ 13 ± 11 10 ± 13

Function 17 ± 21 13 ± 19

Total‡ 19 ± 17 14 ± 18

*SF-12 = Short Form-12, QuickDASH = abbreviated version of theDisabilities of the Arm, Shoulder and Hand (DASH) questionnaire,MEPI = Mayo Elbow Performance Index, and PREE = Patient-RatedElbow Evaluation. †The values are given as the mean and thestandard deviation. ‡The difference was significant (p < 0.05).

Fig. 1 Fig. 2

Fig. 1 The mean range-of-motion measurements (and standard deviation) of the affected and unaffected elbows at a mean follow-up of eight years.

*Significant difference (p < 0.05). Fig. 2 The mean strength measurements (and standard deviation) of the affected and unaffected elbows at a mean

follow-up of eight years. *Significant difference (p < 0.05).

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Fig. 3-A Fig. 3-B

Representative anteroposterior (Fig. 3-A) and lateral (Fig. 3-B) radiographs of an eighty-seven-year-old man, made eleven years after radial head

arthroplasty, showing mild ulnohumeral degenerative changes and mild stem lucency.

Fig. 4-A Fig. 4-B

Figs. 4-A through 4-F A seventy-one-year-old man who had a radial head arthroplasty when he was sixty-two. Figs. 4-A and 4-B Initial anteroposterior

(Fig. 4-A) and lateral (Fig. 4-B) radiographs made at the time of the index procedure.

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Fig. 4-C Fig. 4-D

Fig. 4-E Fig. 4-F

Figs. 4-C and4-DAnteroposterior (Fig. 4-C) and lateral (Fig. 4-D) radiographsmade at the three-year follow-up evaluation.Figs. 4-E and4-F Anteroposterior

(Fig. 4-E) and lateral (Fig. 4-F) radiographs, made nine years postoperatively, showing malalignment of the radiocapitellar and ulnohumeral joints, severe

capitellar erosion, severe ulnohumeral degenerative changes, mild stem lucency, and grade-2 heterotopic ossification.

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No significant differences were found in the range of motion ofthe affected elbow with respect to flexion (p = 0.35), extension(p = 0.30), or pronation (p = 0.52). There was a small butsignificant increase in supination from a mean of 61� ± 16� to67� ± 19� between two and eight years of follow-up (p = 0.021).The affected extremity demonstrated no difference between thetwo periods of follow-up with regard to strength in elbow flexion(p= 0.50) and extension (p= 0.97), strength in forearm pronation(p = 0.056) and supination (p = 0.12), or grip strength (p = 0.10).

Discussion

The clinical and radiographic outcomes at a mean of eightyears after radial head arthroplasty with a smooth-stemmed

modular metallic radial head implant for the treatment of acuteradial head fractures are encouraging. Although radiographic ev-idence of stem lucency and arthritis were common, most patientshad favorable objective and subjective clinical outcomes with noapparent functional deterioration from short to longer-termfollow-up. None of the implants had been removed or revisedat the time of final follow-up.

The patient-reported outcomes scores (SF-12, QuickDASH,and MEPI scores) in the current study are comparable with thosereported in previous shorter-term studies3-5. The differences can beattributed to lower pain scores. Interestingly, we found improvedtotal MEPI and PREE scores in the group of patients followedlongitudinally from two to eight years (Table VI). This was attrib-utable to a significant improvement with regard to pain subscalescores on the PREE and MEPI (Table IV). We postulate that thisimprovement is the result of several factors, including further soft-tissue healing and improved strength and dynamic stability of theelbow over time, increased patient age during the course of follow-up that may result in lower functional demands, and activitymodification to accommodate for elbow pain and dysfunction.

Although the elbow range ofmotion of the affected limbwasless than that of the unaffected limb, the differences were minor

andmay not be clinically relevant. These results are consistent withpreviously reported short-term outcomes3-5. The mean flexion arcof motion of the affected elbow was well within the functionalactivities of daily living range described by Morrey et al.25 and wascomparable with the functional arc of motion for contemporarytasks described by Sardelli et al.26. Range of motion did not dete-riorate significantly in the subgroup of patients followed longitu-dinally. The stiffness seen at the time of the early follow-up did notprogress, suggesting that themild radiographic arthritis, whichwascommonly noted at the longer-term follow-up, did not furtherimpair motion. The 7� improvement in supination, while a sig-nificant increase, is probably not clinically relevant. Our findingsare in agreement with those of Grewal et al., who noted that themajority of the recovery in elbow motion occurs within the firstyear following radial head arthroplasty3. The fact that mo-tion was not evaluated by the same examiner at two years andat eight years of follow-up may render the comparison of thesemeasurements less reliable.

Minor differences in elbow flexion and extension strengthbetween the affected and unaffected elbows were present at the

TABLE VI Categorical Results of MEPI Scores for the SubgroupReviewed at a Mean Follow-up of Two Years and EightYears*

MEPI Category2-Yr Follow-up(no. of patients)

8-Yr Follow-up(no. of patients)

Excellent 17 21

Good 10 6

Fair 5 3

Poor 1 1

*MEPI = Mayo Elbow Performance Index.

TABLE V Longitudinal Comparison of Objective Physical Outcomes Measures in a Subgroup of Thirty-three Patients at a Mean Follow-up ofTwo Years and Eight Years

2-Yr Follow-up* 8-Yr Follow-up*

Affected Arm Unaffected Arm Affected Arm Unaffected Arm

Flexion (deg) 134 ± 9 (116 to 154) 139 ± 7 (126 to 155) 137 ± 16 (60 to 152) 141 ± 18 ( 50 to 157)

Extension (deg) 13 ± 14 (25 to 43) 1 ± 4 (28 to 11) 12 ± 14 (0 to 51) 1 ± 3 (25 to 10)

Pronation (deg) 79 ± 7 (58 to 90) 78 ± 7 (55 to 93) 80 ± 10 (54 to 90) 82 ± 9 (56 to 90)

Supination† (deg) 61 ± 16 (2 to 85) 76 ± 9 (57 to 90) 67 ± 19 (5 to 90) 78 ± 10 (50 to 90)

Flexion strength (Nm) 27 ± 14 ( 0 to 63) 34 ± 18 (7 to 74) 30 ± 16 (7 to 74) 34 ± 20 (8 to 94)

Extension strength (Nm) 28 ± 12 (0 to 65) 34 ± 14 (14 to 78) 29 ± 13 (8 to 62) 32 ± 15 (8 to 83)

Pronation strength (Nm) 5 ± 3 (0 to 15) 6 ± 4 (2 to 18) 6 ± 3 (0 to 17) 7 ± 4 (1 to 19)

Supination strength (Nm) 6 ± 3 (1 to 15) 7 ± 3 (2 to 16) 6 ± 3 (1 to 16) 6 ± 3 (2 to 18)

Grip strength (kg) 27 ± 12 (9 to 53) 30 ± 10 (18 to 58) 30 ± 11 (12 to 54) 31 ± 11 (12 to 63)

*The values are given as the mean and the standard deviation, with the minimum and maximum in parentheses. †The difference was significant(p < 0.05).

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eight-year follow-up, which is consistent with the findings ofother short-term studies3,4. In addition, recovery of strength aftersurgery is durable for a considerable time period as there was nosignificant change during the longitudinal study.

The radiographic assessment revealed outcomes similar tothose reported in prior short-term studies3,4,6. All implants werefound to be of an appropriate size with no evidence of over-lengthening. This may be related to our substantial experiencewith radial head arthroplasty and surgeon familiarity with thisimplant at our institution.

The rate of radiographic ulnohumeral arthritis in the cur-rent series was 38%, with sixteen of the twenty-one involvedelbows having only mild degenerative changes. This is higher thanthe rate of 19% reported by Grewal et al. at two years with thesame implant used to treat acute radial head fractures3. The cur-rent study suggests there may be minor progression in ulno-humeral degenerative changes from short to mid-term follow-up.

Rates of heterotopic ossification vary widely in the literature,and the definition of what constitutes periarticular calcificationcompared with heterotopic calcification remains unclear27. Themajority of patients with heterotopic ossification in the currentstudy did not have clinically important motion impairment. Al-though major heterotopic ossification was not common, one pa-tient had radioulnar synostosis. This patient had the least favorablescores on theMEPI (46 points) and PREE (79 points) in the series.

Periprosthetic stem lucency is a relatively common findingassociated with the implant used in this study, and the previouslyreported rates of lucency around smooth-stemmed metallic radialhead arthroplasty implants have ranged from 50% to 100%2-4,7.Moro et al.4 and Shore et al.6 separately reported no progression ofstem lucency in patients followed for three years and eight years,respectively. Smooth-stemmed metallic implants are not designedfor osseous ingrowth; therefore, stem lucencies are expected andrelatively common. Although there is insufficient evidence in thecurrent literature to determine whether lucency around smooth-stemmed radial head prostheses represents a benign radiographicfinding or a pathologic process, the lack of deterioration in theassessed outcome parameters suggests that lucency does not affectthe mid-term outcome. Certainly longer-term follow-up is needed.

Reported radial head implant survival rates have variedconsiderably andmay be related to implant design. Flinkkila et al.,in a series of thirty-seven patients who had acute radial headfractures treatedwith a press-fitmonopolar implant, reported thatthe implant removal rate was 24% at a mean follow-up of fiftymonths7. In a study of the outcomes at a mean follow-up of 8.4years after fifty-one bipolar radial head arthroplasties performedwith cement, Popovic et al.8 reported that thirty-seven patientshad evidence of progressive osteolysis at the bone-cement inter-face, but none had required removal of the implant. Most patientshad minimal pain until the osteolysis became severe. Those au-thors advised that cemented bipolar implants be usedwith caution.Harrington et al. reported that mild stem lucencies were commonat a mean of twelve years following radial head replacement with asmooth-stemmed monoblock metallic implant, similar to thoseused in the current study; four of twenty implants required re-moval for elbow pain2. The 100% implant survivorship in the

current study is comparable with the survivorship of smooth-stemmedmetallic radial head replacements reported by Shore et al.at a mean follow-up of eight years6. They found that half of theelbows had evidence of stem lucency, but none required removal.The smooth stem design of the radial implant that we evaluated isintended to permit forearm rotation around the stem, rather thanbetween the implant and the capitellar cartilage. At mid-termfollow-up, the survivorship of the smooth-stemmedmetallic radialhead arthroplasty implants appears to be superior to that reportedfor some press-fit radial head arthroplasty designs and cementedbipolar radial head replacements. Long-term comparative studiesare necessary to draw more definitive conclusions.

Like many retrospective studies, the present investigationhas a number of limitations. The loss to follow-up of 18% of theliving cohort may be explained by the large geographic catch-ment area of our institution and the mobile nature of a popu-lation of relatively young adults. This group of patients may haverecovered well enough not to pursue follow-up at our center, oralternatively, they may have seen surgeons at other institutions.Our study population may not be representative of a typicalorthopaedic practice because of the tertiary referral nature of ourcenter. Only five of the fifty-five patients had an isolated radialhead fracture; the majority had associated ligamentous and os-seous injuries, which may be a consequence of the more severeinjuries being referred to our center.

The outcomes of radial head arthroplasty at eight years offollow-up are comparable with our previously reported short-termoutcomes at two years, with no evidence of functional deteriora-tion. Radial head arthroplasty with a smooth-stemmed metallicmodular implant is a good treatment option for patients with acuteunreconstructible radial head fractures with or without associatedosseous and soft-tissue injuries, and sustained clinical outcomesmay be expected beyond five years of follow-up.

AppendixA description of the surgical technique and postoperativeprotocol and a description of the complications are avail-

able with the online version of this article as a data supplementat jbjs.org. n

Jonathan P. Marsh, MD, FRCSC1

Ruby Grewal, MD, MSc, FRCSC2

Kenneth J. Faber, MD, MHPE, FRCSC2

Darren S. Drosdowech, MD, FRCSC2

George S. Athwal, MD, FRCSC2

Graham J.W. King, MD, MSc, FRCSC2

1Pan Am Clinic, Winnipeg,Manitoba, Canada

2Roth | McFarlane Hand & Upper Limb Centre,St. Joseph’s Health Centre, London,Ontario, Canada

E-mail address for G.J.W. King: [email protected]

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References

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14. Rowland AS, Athwal GS, MacDermid JC, King GJ. Lateral ulnohumeral jointspace widening is not diagnostic of radial head arthroplasty overstuffing. J Hand SurgAm. 2007 May-Jun;32(5):637-41.15. Lanting BA, Ferreira LM, Johnson JA, King GJ, Athwal GS. The effect of radialhead implant length on radiocapitellar articular properties and load transfer withinthe forearm. J Orthop Trauma. 2014 Jun;28(6):348-53.16. MacDermid JC. Outcome evaluation in patients with elbow pathology: issues ininstrument development and evaluation. J Hand Ther. 2001 Apr-Jun;14(2):105-14.17. Vincent J, MacDermid JC. The Patient-Rated Elbow Evaluation (PREE). J Physiother.2012;58(4):274.18. Ware J Jr, Kosinski M, Keller SD. A 12-Item Short-Form Health Survey: con-struction of scales and preliminary tests of reliability and validity. Med Care. 1996Mar;34(3):220-33.19. Beaton DE, Wright JG, Katz JN; Upper Extremity Collaborative Group. Develop-ment of the QuickDASH: comparison of three item-reduction approaches. J BoneJoint Surg Am. 2005 May;87(5):1038-46.20. Morrey BF, An KN. Functional evaluation of the elbow. In: Morrey BF, Sanchez-Sotelo J, editors. The elbow and its disorders: expert consult. 4th ed. Philadelphia:WB Saunders; 2009. p. 80-91.21. Brooker AF, Bowerman JW, Robinson RA, Riley LH Jr. Ectopic ossification fol-lowing total hip replacement. Incidence and a method of classification. J Bone JointSurg Am. 1973 Dec;55(8):1629-32.22. Broberg MA, Morrey BF. Results of treatment of fracture-dislocations of theelbow. Clin Orthop Relat Res. 1987 Mar;216:109-19.23. Gruen TA, McNeice GM, Amstutz HC. “Modes of failure” of cemented stem-typefemoral components: a radiographic analysis of loosening. Clin Orthop Relat Res.1979 Jun;141:17-27.24. Gustilo RB, Anderson JT. Prevention of infection in the treatment of one thou-sand and twenty-five open fractures of long bones: retrospective and prospectiveanalyses. J Bone Joint Surg Am. 1976 Jun;58(4):453-8.25. Morrey BF, Askew LJ, Chao EY. A biomechanical study of normal functionalelbow motion. J Bone Joint Surg Am. 1981 Jul;63(6):872-7.26. Sardelli M, Tashjian RZ, MacWilliams BA. Functional elbow range of motion forcontemporary tasks. J Bone Joint Surg Am. 2011 Mar 2;93(5):471-7.27. Morrey BF, Harter GD. Ectopic ossification about the elbow. In: Morrey BF,Sanchez-Sotelo J, editors. The elbow and its disorders: expert consult. 4th ed.Philadelphia: WB Saunders; 2009. p 472-86.28. Regan W, Morrey B. Fractures of the coronoid process of the ulna. J Bone JointSurg Am. 1989 Oct;71(9):1348-54.

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Radial Head Fractures Treated with Modular Metallic Radial Head …jc.dalortho.ca/wp-content/uploads/2016/04/radial-head... · 2016. 4. 11. · Background: Radial head arthroplasty