Abstract
Background: Metallic radial head arthroplasty is a proven technique for the treatment of complex radial head fractures. The purpose of this study was to evaluate the functional outcomes of a metallic radial head arthroplasty in patients with chronic posttraumatic elbow disorders.
Methods: The results of thirty-two metallic radial head arthroplasties in thirty-two consecutive patients were retrospectively reviewed. The indications for the radial head arthroplasty included posttraumatic nonunion and malunion of the radial head, elbow instability following previous excision of the radial head, and failure of a silicone radial head implant used to treat an acute radial head fracture. The study included thirteen male and nineteen female patients followed for a minimum of two years. The radial head arthroplasties were performed at an average of 2.4 years after the injury. Analysis included chart review, personal interview, physical examination, radiographic examination, and strength testing as well as the administration of general and region-specific questionnaires.
Results: The mean duration of follow-up was eight years. The average Mayo Elbow Performance Score was 83 of 100 points, with seventeen (53%) of the thirty-two results rated as excellent; four (13%), as good; seven (22%), as fair; and four (13%), as poor. The average score for subjective patient satisfaction was 8.5 points on a 10-point scale. Patients had significantly less motion and strength in the affected elbow than in the unaffected elbow. Seventy-four percent of the patients demonstrated some degree of posttraumatic arthritis. There were no significant differences in ulnar variance and the ulnohumeral joint space between the affected and unaffected arms. Over the course of the study, no metallic radial head arthroplasties required revision.
Conclusions: Metallic radial head arthroplasty for the treatment of posttraumatic elbow disorders appears to be a safe and durable procedure that can provide a functional range of motion and pain relief for at least five to ten years. However, longer follow-up is needed to evaluate progression of lucencies adjacent to stems and osteoarthritis.
Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.
Radial head fractures account for about one-third of all adult elbow fractures1. Treatment options for radial head fractures include splinting, open reduction and internal fixation, early or delayed radial head excision, and radial head reconstruction2. Fragment size, the number of fragments, the degree of displacement, and bone quality all influence decision-making regarding the optimal management3. Recently, metallic radial head arthroplasty has been used to treat patients with chronic posttraumatic elbow disorders, specifically those with a failed open reduction and internal fixation, a failed silicone radial head implant, or instability following radial head resection.
Historically, complex radial head and neck fractures were treated with open reduction and internal fixation or excision. However, the results of open reduction and internal fixation of comminuted, displaced radial head and neck fractures have been less predictable, particularly when there have been more than three fracture fragments4,5. Failure of open reduction and internal fixation caused by osteonecrosis, nonunion, or fragment displacement can lead to articular injury to the capitellum and radial notch of the ulna. Pain and stiffness frequently require further treatment, and one option has been radial head arthroplasty. The long-term outcomes of that procedure in these patients are unknown.
Recent reports in the literature have demonstrated that radial head excision is contraindicated for patients with an incompetent medial collateral ligament or forearm interosseous ligament or an elbow dislocation5-7. These patients can experience long-term problems, such as symptomatic proximal translation of the radius, a decrease in strength, degenerative changes in the wrist and elbow, and cubitus valgus. At our institution, metallic radial head arthroplasty has been used to treat patients with chronic posttraumatic elbow problems. The purpose of this study was to assess the functional outcome of metallic radial head arthroplasty performed for the treatment of chronic posttraumatic elbow disorders.
After receiving approval from our local ethics committee, we retrospectively reviewed the cases of thirty-six patients who had undergone metallic radial head arthroplasty between 1993 and 2004 at a single hospital. Three fellowship-trained orthopaedic surgeons performed the arthroplasties. To be included in the study, a patient had to be skeletally mature and to have received a metallic radial head arthroplasty for the treatment of a posttraumatic elbow disorder more than four weeks after the date of the initial injury. Indications for the arthroplasty included nonunion, malunion, recurrent instability following a previous radial head excision, and a failed silicone radial head implant. Four patients were lost to final follow-up and were not included in the analysis. Three had moved and were unable to be contacted, and one had died. At the time of their last follow-up, all four patients reported that the elbow was functioning well.
Thirty-one patients (thirty-one arthroplasties) returned to our center for a comprehensive examination by one of us (B.J.S.). One patient was unable to return to the hospital for radiographs because of medical comorbidities. Her outcome data were included, and we visited her at her home to perform a clinical evaluation. There were thirteen men and nineteen women with a mean age (and standard deviation) of 54 ± 12.4 years (range, thirty-two to ninety-three years). The dominant arm was involved in twelve of the thirty-two patients. Six patients had initially sustained an isolated fracture of the radial head, and the remaining twenty-six had a constellation of ipsilateral injuries. Seventeen patients had an associated elbow dislocation at the time of injury. Of these seventeen patients, seven had sustained the so-called terrible triad injury, which we defined as an elbow dislocation associated with both a coronoid fracture and a radial head fracture (see Appendix). There were no open fractures or dislocations. Twenty-two patients received a monoblock metallic radial head implant (Smith and Nephew Richards, Memphis, Tennessee), and ten patients received a modular metallic radial head implant (Evolve; Wright Medical Technology, Arlington, Tennessee).
The mean time from the injury to the metallic radial head arthroplasty was 2.4 years (range, two months to eighteen years). Twenty (63%) of the thirty-two patients were originally injured in a fall from a standing height, six patients fell from a height of >6 ft (>1.8 m), two fell from a bicycle, two were involved in a motor-vehicle collision, and two had a crush injury to the forearm. Eight injuries (25%) were work-related and the subject of a Workers' Compensation claim.
Patients were classified into four groups according to the initial failed treatment regimen. Twelve patients were initially treated with open reduction and internal fixation of the radial head (Group A), eleven were initially treated nonoperatively (Group B), six were initially treated with radial head excision and a silicone implant (Group C), and three were initially treated with acute radial head excision (Group D). Group-A patients had had a mean of 1.2 operations prior to the metallic radial head arthroplasty and a mean of 3.3 associated ipsilateral elbow procedures performed at the time of the index surgery. In comparison, patients in group C had had a mean of two operations prior to the metallic radial head arthroplasty and a mean of 5.7 associated ipsilateral elbow procedures performed at the time of the index surgery. No patient underwent a revision of the radial head arthroplasty; however, seven patients required a subsequent operation (see Appendix).
Surgical Technique and Postoperative Care
All implants were placed through a midline posterior elbow incision to avoid damage to cutaneous nerves and to allow medial and lateral deep muscle interval dissection as required8. A full-thickness lateral flap was developed on the deep fascia. In many cases, the common extensor origin was intact or entrapped by scar tissue and the Kocher interval between the extensor carpi ulnaris and the anconeus was developed and the radial collateral and annular ligaments were divided at the midportion of the radial head. The radial collateral ligament was elevated off the anterior aspect of the lateral epicondyle as needed for further exposure. The lateral ulnar collateral ligament, the key stabilizer against varus and posterolateral rotatory instability9, was kept intact when possible. If the lateral collateral ligament was completely detached, it was repaired through drill-holes in the lateral epicondyle during closure, except in six patients who had an initial osteotomy of the lateral epicondyle for exposure. The detailed surgical technique for implanting metallic radial head prostheses has been described elsewhere10.
We used two radial head implants. From 1993 to 1999, a monoblock uncemented titanium radial head (Smith and Nephew Richards) was implanted. When modular implants became available in 2000, all three surgeons switched to using an uncemented cobalt-chromium implant (Evolve) because of the improved sizing options and ease of implantation of a modular system. The diameter and thickness of the implant were selected on the basis of careful measurement of the excised radial head, if it was available, or by templating contralateral radiographs. On direct inspection of the joint, an implant was judged to be of the correct thickness if it articulated at the same level as the radial notch of the ulna and was 1 mm distal to the coronoid. A fluoroscopic examination was also performed to confirm the aforementioned relationship of the height of the prosthesis to the proximal part of the ulna and restoration of normal ulnar variance. Our group recently reported that the width of the medial ulnohumeral joint space is consistent and the articulation is normally parallel11. If the medial ulnohumeral joint space was not parallel and was wider laterally, the prosthesis was judged to be too thick and therefore was downsized. At the time of the arthroplasty, seven patients had a total of eight additional operations, including ulnar nerve transposition, removal of a hinged external fixator, removal of a prominent plate, distal ulnar shortening osteotomy, and distal ulnar arthroplasty.
The postoperative rehabilitation protocol was standardized. Within one to two days postoperatively, all patients performed active range-of-motion exercises supervised by a hand therapist. Patients with a stable reconstruction were provided with a collar and cuff to wear between exercises. When a patient had associated lateral-sided ligamentous injuries, the forearm was splinted in maximal pronation at 90° of elbow flexion for the first six weeks. When there were associated medial-sided ligamentous injuries, the forearm was splinted in maximal supination at 90° of elbow flexion for the first six weeks. If both medial and lateral-sided ligamentous injuries were present, the forearm was splinted in neutral rotation. Active flexion and extension exercises were performed within a "safe" arc of motion as dictated by the associated osseous and soft-tissue injuries. An extension night splint was employed for elbows that were stable in extension to optimize restoration of terminal elbow extension. Forearm pronation and supination exercises were performed actively with the elbow in 90° of flexion or as dictated by the degree of ligamentous stability12. After six to eight weeks, active and passive stretching and strengthening exercises were initiated12. Postoperatively, patients were given indomethacin (25 mg by mouth three times a day) for prophylaxis against heterotopic ossification for three weeks.
Outcome Measures
Self-report scales were used to evaluate different health perspectives, including general health (Short Form-36 [SF-36] Health Survey)13,14, upper-extremity disability (Disabilities of the Arm, Shoulder and Hand Questionnaire [DASH])14,15, and pain and disability specific to the elbow and wrist (Patient-Rated Wrist Evaluation [PRWE]16,17, Patient-Rated Elbow Evaluation [PREE]18, and American Shoulder and Elbow Surgeons self-report form [ASES])19. The Mayo Elbow Performance Score (MEPS)20, an elbow impairment and functional index, was calculated with use of five specific self-reported responses on the PREE that are mapped to MEPS items as well as with measurements of strength and motion impairments. Grip-strength and range-of-motion testing was performed with use of the NK Hand Evaluation System (NK Biomechanical Engineering, Minneapolis, Minnesota). Instruments were calibrated prior to each test session, and standardized protocols were used to measure grip21 and motion22. The LIDO Workset (Loredan Biomedical, West Sacramento, California) was used for isometric testing of elbow flexion, extension, pronation, and supination strength. Testing was performed with the elbow in 90° of flexion and the forearm in neutral rotation23.
Radiographs, including anteroposterior and lateral views of each elbow and wrist, were evaluated postoperatively, two years after the surgery, and at the time of final follow-up. The radiographs were reviewed for congruity of the radial head with the capitellum, evidence of capitellar osteopenia and erosion, sizing of the prosthesis, periprosthetic lucency, heterotopic ossification, joint incongruity, and osteoarthritis. Capitellar osteopenia and erosion were graded as present or absent. The size of the prosthesis was evaluated by comparing the widths of the medial and lateral ulnohumeral joint spaces of the operatively treated and uninvolved elbows on follow-up anteroposterior radiographs11. If the width of the lateral ulnohumeral joint space was increased relative to that in the contralateral elbow or if the medial ulnohumeral joint space was not parallel and was wider laterally, the prosthesis was considered to be too thick (overstuffing). We defined radiolucency as any discrete 1-mm region of decreased bone density around the prosthesis24. Periprosthetic lucency around the stem was graded as none, mild, moderate, or severe on the basis of the number of involved zones, as defined with a modification of the Gruen classification for the hip (Figs. 1-A and 1-B)25 and the amount of lucency observed (in millimeters). Lucency was rated as mild if fewer than three zones were involved by lucency of <2 mm in thickness, moderate if three to six zones were involved or there was lucency of >2 mm in thickness in any one location, and severe if all seven zones were involved26. Heterotopic ossification was graded with use of the Hastings and Graham classification according to its location and the functional restrictions in the range of motion27. The degree of degenerative change was graded with the system outlined by Broberg and Morrey, with grade 0 representing a normal joint, grade 1 representing slight joint space narrowing and minimum osteophyte formation, grade 2 representing moderate joint space narrowing and moderate osteophyte formation, and grade 3 representing severe degenerative changes with gross destruction of the joint28. The four-stage Mayo elbow classification for rheumatoid arthritis, which describes the radiographic signs of progression of rheumatoid arthritis, was used for one patient in our study. Stage 1 represents no radiographic abnormalities except periarticular osteopenia, mild synovitis, and soft-tissue swelling, whereas stage 4 demonstrates extensive articular damage with loss of subchondral bone and subluxation or ankylosis of the joint29,30.
Statistical Methods
Data were entered by research assistants and analyzed by one of us (B.J.S.). Descriptive statistics were used to identify outliers and to determine normality of data. Paired t tests were used to assess the difference between affected and unaffected sides at the time of final follow-up (a = 0.05). Pearson correlations were used to determine the relationship among variables of interest.
The details of each patient's injuries, treatment, complications, and outcomes are presented in tables in the Appendix. The mean duration of follow-up was eight years (range, two to fourteen years). At the time of follow-up, range-of-motion measurements demonstrated a significant mean loss of 10° of extension of the treated elbow as compared with the contralateral, normal elbow (p < 0.05) (Fig. 2). No significant difference in elbow flexion or forearm rotation was seen between the affected and unaffected limbs. Grip strength was significantly decreased (p < 0.01) on the side of the injury, as was isometric flexion, extension, supination, and pronation strength (p < 0.03) (Fig. 3).
Nine patients had complications, the majority of which were self-limited and not clinically relevant at the time of final follow-up. New heterotopic ossification developed after the arthroplasty in three patients, whereas seven elbows had had heterotopic ossification prior to the arthroplasty. All three new cases were graded as Class I and were asymptomatic, causing no functional limitations of motion27. Two of these patients had medical contraindications to indomethacin and had not received postoperative indomethacin or radiation. Four patients had neurologic complications. Two of them had a transient sensory ulnar neuropathy. One patient had a moderate ulnar neuropathy, with persistent intrinsic muscle weakness requiring transposition of the ulnar nerve31 one year after the arthroplasty. The fourth patient had a posterior interosseous nerve palsy, which completely resolved by six months following the surgery. That palsy was probably the result of exposure and neurolysis of the posterior interosseous nerve, which was required to facilitate the safe removal of adjacent heterotopic bone. One patient had chronic regional pain syndrome (Type I)32. This patient's symptoms decreased over a nine-month period with a combination of intensive therapy and medication (opioid, anti-inflammatory, and antiseizure medication). At the time of final follow-up, there had been no implant revisions or fractures.
Nine patients had to change their occupation because of residual limitations from the elbow injury. At the time of follow-up, twenty patients did not take analgesics, ten patients took analgesics occasionally, and two patients took analgesics (acetaminophen with codeine and acetaminophen with oxycodone) regularly.
According to the Mayo Elbow Performance Score, there were seventeen excellent results, four good results, seven fair results, and four poor results (Table I). The eleven fair and poor results were associated with other injuries or a comorbid medical or psychiatric condition (three), a Workers' Compensation claim (six), or litigation regarding Worker's Compensation (two). The eight patients with a Workers' Compensation claim had a significantly lower mean MEPS score (63 points) compared with the mean score (93 points) for the remainder of the cohort (p < 0.001). These eight patients also had lower mean SF-36 scores for mental performance (42 points) and physical performance (38 points) compared with the remainder of the cohort.
The SF-36, DASH, MEPS, ASES, PREE, and PRWE scores are shown in the Appendix.
Radiographic evaluation demonstrated that thirty-one of the thirty-two implants articulated congruently with the capitellum with a concentric ulnohumeral joint. One patient had Charcot arthropathy with dislocation of the radiocapitellar and ulnohumeral joint. There were no cases of clinical loosening or instability of any of the twenty-two monoblock or ten modular implants used in this cohort. Fourteen patients demonstrated capitellar osteopenia, and two demonstrated capitellar erosions (Table II). The radiographic appearance of the metallic prosthesis precluded an evaluation for the presence of sclerosis. With the numbers studied, no significant difference in the width of either the medial or the lateral ulnohumeral joint space was seen between the affected and unaffected elbows (Table II). Also, there was no significant difference in ulnar variance between the affected and unaffected limbs. The ulnar variance in the affected limbs was ulnar positive (mean and standard deviation, +1 ± 4 mm), whereas the ulnar variance in the unaffected limbs was ulnar neutral (0 ± 3 mm).
At the time of final radiographic follow-up (performed for thirty-one of the thirty-two elbows), fifteen elbows showed no evidence of lucency around the stem of the prosthesis. There was minor lucency around the stem (<2 mm in fewer than three zones) in ten elbows, moderate lucency around the stem (>2 mm or involvement of three to six zones) in four, and severe lucency around the stem (involvement of all seven zones) in two (Fig. 4). No significant differences were identified between the two types of implants with respect to the degree and location of periprosthetic lucency or the progression of lucency from two years postoperatively to the time of final follow-up.
Nine elbows did not demonstrate osteoarthritis at two years or the time of final follow-up. Ten elbows demonstrated mild osteoarthritis; eleven, moderate osteoarthritis; and one, severe osteoarthritis in the form of Charcot arthropathy.
In a review of the literature, we were unable to find previous reports on the functional outcome of metallic radial head arthroplasty for the treatment of chronic posttraumatic elbow disorders. At an average of eight years postoperatively, we found metallic radial head arthroplasty to be a safe and reliable procedure. The longevity of metallic radial head implants has been previously questioned, and we are aware of only four survival studies in the literature24,26,33,34. There was a 100% rate of survival of the radial head implants in our study up to a maximum of fourteen years. As expected, we did find differences in grip and elbow strength between the affected and unaffected limbs. With regard to the range of motion, our patients lost an average of 10° of elbow extension compared with that of the contralateral limb, but little differences in flexion, pronation, and supination were observed.
Radiographically, we did not see a significant difference in ulnar variance between the affected and unaffected wrists. Two patients had an Essex-Lopresti lesion and underwent a subsequent distal ulnar shortening osteotomy to correct symptomatic ulnar variances of 9.8 and 12.3 mm. Van Glabbeek et al.35 demonstrated that a change in ulnar variance of 2.5 mm alters elbow and wrist kinematics following implantation of a radial head replacement. Patients in our series with a positive ulnar variance did not demonstrate substantial wrist impairment as measured with the patient-rated wrist evaluation questionnaire.
Periprosthetic radiographic lucencies were seen in this cohort, but we did not observe substantial progression of the lucencies from two years postoperatively to the time of final follow-up. Radiographic lucencies are expected with both of the implant designs that were employed in this study, and with the numbers studied we did not find differences with regard to the degree, location, or progression of lucencies between the two types of implants. Lucencies indicate that the stem is mobile within the proximal part of the radius, which allows the radial head to maintain a congruent articulation with the capitellum throughout motion. Perhaps, with a larger sample size, we would have had the power to detect significant differences in the clinical and radiographic outcomes between the two prosthetic designs.
Fourteen patients demonstrated capitellar osteopenia. The cause of this phenomenon is unknown. It was previously reported in two series and a case report, involving patients treated with similar implants for acute radial head arthroplasty26,35,36. We speculate that decreased loading across the radiocapitellar articulation may have been responsible for the observed changes, which were possibly due to resorption of bone over time at the proximal part of the radius when the implant was correctly sized or to implantation of an insufficiently thick prosthesis at the time of the initial surgery.
Overstuffing was not observed in this series, probably because of our extensive experience with the use of these implants for the management of acute radial head fractures. We routinely made radiographs of the contralateral elbow to assist with implant sizing. Furthermore, the thickness of the prosthesis was chosen to reflect the thickness of the excised radial head, if it was available. The height of the implant was compared with its articulation with the radial notch of the proximal part of the ulna. Ideally, the proximal surface of the prosthesis should lie about 1 mm distal to the tip of the coronoid process11. Intraoperative fluoroscopy was employed to evaluate the congruity of the implant on the capitellum. Our group recently reported that the width of the medial ulnohumeral joint space is consistent and the articulation is normally parallel while the lateral ulnohumeral joint space is often not parallel and wider laterally11 (Fig. 5-A and 5-B). If, during intraoperative fluoroscopy with the elbow reduced, the medial ulnohumeral joint space was not parallel and was wider laterally, the prosthesis was judged to be too thick and therefore was downsized. In the setting of a radial head replacement for reconstruction, the lateral ligament of the elbow is typically intact, which is not the case with acute trauma. Overstuffing of a radial head implant in this setting is less likely than it is in the setting of acute trauma because of the difficulty of inserting a prosthesis that is too thick when the lateral ligament is intact.
All patients received a metallic radial head arthroplasty for the treatment of posttraumatic problems; however, the study group was diverse, with four distinct patient populations. The power of formal statistical analysis of these differences was hindered by the small number of patients in each subgroup (Table I).
Our results are comparable with those in previous reports on acute radial head arthroplasties in the literature24,26,33,34. Most recently, Grewal et al.26 prospectively evaluated twenty-six patients in whom an unreconstructable radial head fracture had been treated with a modular metallic radial head prosthesis. Over a twenty-four-month follow-up period, sixteen of twenty-four patients for whom the MEPS score was calculated rated the elbow as good or excellent, with an average MEPS score of 83 points. Moro et al.24 reported the functional outcome of a monoblock metallic radial head arthroplasty in twenty-five patients followed for an average of 3.5 years. The result was rated as good or excellent in seventeen patients, as fair in five, and as poor in three, with an average MEPS score of 80 points. Harrington et al.34 followed twenty patients with a metallic radial head arthroplasty for an average of twelve years and reported sixteen excellent or good results and four fair or poor results, with an average MEPS score of 88 points. In the current study, the mean MEPS score was 83 points, with twenty-one excellent or good results and eleven fair or poor results. Patients in whom an initial open reduction and internal fixation of the radial head fracture had failed had functional scores that were similar to those reported in the literature for patients treated with a metallic radial head arthroplasty for an acute fracture.
The long-term results of radial head excision are quite variable. Broberg and Morrey37 reported the results for twenty-one patients who had undergone delayed (for one month to twenty years) excision following failed nonoperative treatment of a radial head fracture; the mean duration of follow-up was fifteen years. Mild-to-moderate osteoarthritis was present in 76% (sixteen) of the patients. Mikic and Vukadinovic38 reported osteoarthritis in 52% and residual symptoms in 43% of fifty-eight patients who had been treated with excision of a radial head and followed for an average of 6.5 years. Fifty percent of the patients had a fair or poor result, and 25% had symptomatic proximal migration of the radius with symptoms related to the distal radioulnar joint. In the present study of patients with a metallic radial head arthroplasty, reduced mobility of the elbow joint was the most common symptom and reduced extension was the most common finding at a mean of eight years, and the results were comparable or superior to those reported in the literature for patients treated with radial head excision. Patient satisfaction was high in the present series, and only 34% of the patients had MEPS scores of fair or poor.
Posttraumatic arthritis was common in our study, with twenty-one (68%) of thirty-one patients demonstrating mild or moderate radiographic changes at the time of final follow-up. Nine patients (29%) had no evidence of posttraumatic arthritis at the time of final follow-up. This prevalence of arthritis was greater than what has been reported in the literature following acute radial head arthroplasty22,34. Harrington et al.34, who used implants similar to those employed in our study, reported that 50% of their patients had evidence of mild osteoarthritis at an average of 12.1 years following metallic radial head arthroplasty for an acute fracture. In comparison, Moro et al.24 found a 20% prevalence of mild osteoarthritis at a mean of three years following metallic radial head reconstruction for the treatment of unreconstructable fractures of the radial head. The greater prevalence of posttraumatic arthritis in our study may be attributed to the fact that, at the time of the index surgery, some of our patients had preexisting posttraumatic arthritis due to chondral damage of the capitellum caused by protruding failed hardware, elbow instability, or a poorly articulating radial head prosthesis. Because of the retrospective nature of this study, we were unable to identify how many patients had had preexisting posttraumatic arthritis.
Despite the frequent presence of osteoarthritis in our cohort, the overall MEPS scores were high at the time of final follow-up. The eleven patients with moderate osteoarthritis reported pain with functional activities and had an average MEPS score of 79 points. In comparison, the ten patients with mild osteoarthritis had few functional limitations and had an average MEPS score of 93 points. These data suggest that, while the reported functional outcomes of acute and chronic radial head arthroplasty are similar at eight years, the prevalence of osteoarthritis may be higher after delayed reconstruction when additional damage to the capitellar cartilage, over and above that present at the time of the initial fracture, has occurred. Additional studies are needed to address this issue.
The patients who initially were treated nonoperatively had the lowest MEPS and patient satisfaction scores and had the greatest number of secondary operations. The majority (six) of the eleven patients in this group had an elbow fracture-dislocation and were initially treated with closed reduction and splinting. The literature suggests that complex elbow fracture-dislocations are best treated initially with operative intervention, and this can explain the poor results in this group37-41. Patients with failed open reduction and internal fixation had better-than-expected functional outcome scores. Because many of the patients in this study underwent the primary surgery at another institution it is not possible to identify the total number of patients treated with open reduction and internal fixation elsewhere and calculate the proportion who required a secondary procedure. Whether it is reasonable to attempt to fix a comminuted radial head fracture primarily, with the knowledge that a secondary metallic radial head arthroplasty has a reasonable outcome, requires further prospective study.
Our study was limited by its retrospective nature, with a lack of preoperative questionnaire data and a modest loss to follow-up. In addition, the patient group was, by nature, somewhat heterogeneous. The indications for radial head replacement were variable, and a large number of concomitant operative procedures were performed, which may have influenced patient outcomes. In addition, both modular and monoblock implant designs were used.
In conclusion, at an average of eight years postoperatively, we demonstrated that metallic radial head arthroplasty for the reconstruction of elbows with a chronic posttraumatic disorder is a reliable and safe treatment option, with a 100% implant survival rate and satisfactory outcome scores. However, further long-term follow-up is needed to monitor for progression of lucencies around the stems and osteoarthritis.
Tables showing the details of all cases and the clinical outcomes are available with the electronic versions of this article, on our web site at (go to the article citation and click on "Supplementary Material") and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM). 
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