The biomechanical effect of prosthetic design on radiocapitellar stability in a terrible triad model

Plate or Arthroplasty for complex Mason Type-III Radial Head Fractures? Mid-to-long term results from a blinded outcome assessor study

BACKGROUND

The surgical treatment of radial head fractures like Mason type III comminuted radial head fractures is challenging and controversial. Whether to use open reduction and internal fixation (ORIF) or radial head arthroplasty (RHA) as treatment methods is under constant debate.

METHODS

We retrospectively analyzed clinical and radiographic mid- to long-term results of 42 patients with a mean follow-up time of 4.56 years (1.92-7.58 years). Patients were grouped according to fragment numbers and the type of intervention performed (3-4 fragments vs. 4+ fragments; ORIF vs. RHA). At the final follow-up, range of motion (ROM), functional rating scores and subjective pain and function levels were documented by a blinded outcome assessor.

RESULTS

Although minor differences in the mean values were detected when comparing the results of the functional scores, ROM and subjective pain and function levels, only the movement in pronation and supination direction yielded statistically better results in the group of 4+-fragments for the RHA compared to ORIF. However, the 33 % rate of required implant removal amongst the ORIF group should be considered.

CONCLUSIONS

This study provides evidence that 3- and 4-part Mason type III fractures are prone to plate osteosynthesis. In contrast, greater than 4-part fractures can more reliably be treated by replacement. This leads to a proposed increase in fragment numbers to four, where ORIF most likely leads to good clinical results. However, in patients with 4+ fragment patterns, ORIF did not show statistically significantly worse results concerning the collected clinical values. This study supports the use of the ORIF approach to save the radial head.

Uncementing the status quo: systematic review of a loose-fit, polished stem radial head prosthesis shows stable clinical results in complex elbow injuries with a concomitant radial head fracture

INTRODUCTION

Selecting the optimal radial head prosthesis to treat radial head fractures, especially in the context of complex elbow injuries like terrible triad, Monteggia, and Essex Lopresti, can be challenging, as there is currently no consensus in the field that favors a particular design. This study investigated the safety and performance of a Polished Stem Radial Head Prosthesis (PS RHP) compared to other modern RHP designs.

MATERIALS AND METHODS

A systematic review was conducted according to PRISMA guidelines to capture data on a Polished Stem Radial Head Prosthesis (PS RHP) and other Radial Head Prostheses (RHPs). Functional scores, range of motion, complications, and revisions were extracted from published literature and analyzed in parallel with the percentage of complex injuries. Comparison of functional outcomes between groups were based on minimum clinically important differences (MCIDs).

RESULTS

There were 16 articles reporting on 711 cases of the PS RHP and 23 articles reporting on 605 cases of other RHPs included in the systematic literature review. Functional scores and range of motion were similar amongst the groups. The PS RHP design achieved a comparable revision rate as other RHPs despite a higher number of terrible triad injuries. Notably, the PS RHP group showed a significantly lower rate of instability (1.0%) than other RHPs (3.4%) (p < 0.05). Other complication rates were similar amongst the two groups.

CONCLUSIONS

The PS RHP group had higher rates of terrible triads at baseline compared to the other RHPs group. Regardless of greater injury complexity, the clinical outcomes of the PS RHP group were favorable and resulted in a significantly lower rate of postoperative instability as compared to other RHPs.

Management of Elbow Terrible Triad Injuries: A Comprehensive Review and Update

The "terrible triad" of the elbow, encompassing elbow dislocation, radial head fracture, and coronoid process fracture, remains a formidable challenge in orthopaedic practice. Typically, stabilizing structures in the elbow fail from lateral to medial through a posterolateral rotatory force after a fall onto an outstretched upper extremity. Surgery is often needed to repair the lateral ligamentous complex, replace or fix the radial head, possibly repair the anterior capsule or fix the coronoid, and consider medial repair or application of an internal versus external fixator. However, in some challenging cases persistent instability, complications, and loss of function may occur. Rehabilitation focuses on achieving early range of motion to prevent stiffness which can be common after these injuries. By integrating emerging approaches with established practices, this article aims to guide orthopaedic surgeons toward a fundamental understanding of terrible triad injuries and assist with informed management principles of these complex injuries.

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

BACKGROUND

Radial head arthroplasty allows a high degree of customizability, and implant polarity has emerged as an important variable. The purpose of this meta-analysis was to evaluate differences in functional and clinical outcomes between patients receiving monopolar and bipolar radial head prosthetic implants.

METHODS

A systematic review and meta-analysis were employed, and 65 articles were identified in three databases. Twelve articles contained non-English or insufficient text and were consequently excluded, and 20 others did not contain sufficient data or follow-up. The remaining 33 articles were qualitatively and quantitatively reviewed.

RESULTS

In total, 33 populations were identified, with 809 unduplicated patients: 565 with monopolar and 244 with bipolar implants. In these respective patients, the mean follow-up was 40.2 and 56.9 months. Average Mayo Elbow Performance Score were 86.7 and 87.4 (P=0.80), respectively; average Disability of the Arm, Shoulder, and Hand scores were 17.9 and 14.7 (P=0.47), and average final flexion/extension arcs were 119.4° and 118.7° (P=0.48). Revision rates were 4.07% and 6.56%, while complication rates were 19.65% and 20.08% in the respective monopolar and bipolar patients. These increased relative risks associated with bipolar implants were not significant.

CONCLUSIONS

Radial head implant polarity does not appear to affect functional outcomes. While bipolar prosthetic design may increase the risks of revision and complications, the increases were not significant. Level of evidence: IV.

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.

Improved Understanding of Traumatic Complex Elbow Instability

Recent advancements in surgical treatment have improved clinical results in complex traumatic elbow injury. There is increasing recognition that conservative treatment and inadequate surgical fixation carry high risk of substantial morbidity in many of these cases. Recent literature displays improved outcomes in complex elbow instability, in part, because of a more complete comprehension of the injury patterns and fixation methods. Prompt surgical management with stable internal fixation, which permits immediate postoperative mobilization, has been a consistent variable across the reports leading to more satisfactory outcomes. This applies to both acute and chronic cases.

A novel and superior Lasso-plate technique in treatment for coronoid process fracture in the terrible triad of elbow

The treatment of ulna coronal process fractures in the terrible triad of elbow, especially type I and II Regan-Morrey coronoid fractures, still have been controversial. The purpose of this retrospective study was to evaluate the novel Lasso-plate technique to have a more reliable fixation and a well clinical outcomes for type I and II Regan-Morrey coronoid fractures in a terrible triad of the elbow (TTE). Patients with simple TTE, closed fracture, aged > 18 years, duration of injury < 2 weeks, type I and II Regan-Morrey coronoid process fracture fixed by the Lasso-plate technique or ORIF were enrolled in the study. Total 144 patients with type I and II Regan-Morrey coronoid fracture in TTE were included in the Lasso-plate group or ORIF (open reduction and internal fixation) group in the Xi'an Honghui Hospital from January 2017 to December 2020. Eighty-six patients in Lasso-plate group underwent surgery using a novel Lasso-plate technique. And other 58 patients in ORIF group underwent surgery using ORIF. The data of two groups, including the X-ray films, Computed tomography (CT), the range of elbow motion, Mayo Elbow Performance Score (MEPS) and the surgical complications, were extracted from the hospital's patient records. All patients in both groups were followed up at least 12 months. The mean operation time (88.2 ± 12.3 min) in Lasso-plate group is shorter than that of ORIF group (109.1 ± 13.0 min). There was one patient with injury of deep branch of radial nerve and one patient with superficial surgical incision infection in Lasso-plate group. There were two patients with surgical incision infection in ORIF group. There were three heterotopic ossifications in Lasso-plate group and eight heterotopic ossifications in ORIF group. There were 5 elbow joints stiffness in Lasso-plate group and 12 in ORIF group. At 12 months follow up, the mean range of flexion-extension motion in Lasso-plate group was 122.9° ± 13.4° versus 113.2° ± 18.1° in ORIF group (p < 0.01), the mean 89.7 ± 5.6 MEPS in Lasso-plate group versus mean 83.7 ± 6.1 MEPSin ORIF group. The fixation of coronoid process fracture in TTE by the Lasso-plate technique, especially type I and II Regan-Morrey coronoid fracture, could be easier to master and operate, could provide the sufficient stability of elbow joint to enable early functional exercise, along with a better clinical outcome, a lower surgical complication. For the treatment of TTE, we recommend the fixation of type I and II Regan-Morrey coronoid fracture with the Lasso-plate technique, which would result in a better clinical outcome.

[Radial head arthropolasty in unreconstructable comminuted fractures of the radial head: Long-term results and factors influencing the outcome]

BACKGROUND

Radial head arthroplasty is recognized as the gold standard in the treatment of patients with unreconstructable radial head fractures.

OBJECTIVE

The aim of this retrospective study was to investigate the long-term results after prosthetic replacement of the radial head and in a subgroup analysis to identify factors which influence the outcome.

MATERIAL AND METHODS

A total of 48 patients with unreconstructable fractures of the radial head and neck were treated by cementless radial head arthroplasty between 05/2008 and 10/2018 (30 bipolar prosthesis type rHead Recon, 18 monopolar prosthesis type MoPyc). After a mean follow-up of 4.6 years 39 patients were assessed clinically and radiologically.

RESULTS

The median MEP score was 95 points. Compared to the uninjured side the median range of motion was reduced by 10° for extension/flexion as well as for pronation/supination. In 36 of 39 cases an osseous integration of the prosthesis could be documented. One prosthesis had to be removed after 23 months because of painful loosening. Overlengthening was present in 11 cases (28%), 25 patients (64%) had subcollar bone resorption with a stable osteointegrated stem. Nonbridging heterotopic ossification was observed in 15 patients (38%), 16 patients (41%) showed posttraumatic arthrosis. Patients with sustained elbow dislocation had a significantly worse function in the MEP score and tended to develop an arthrosis more frequently. Ulnohumeral joint degeneration was significantly increased when overlengthening was present.

CONCLUSION

Radial head arthroplasty is an effective treatment option for unreconstructable fractures of the radial head and can provide good to excellent mid-term to long-term results. Sustained elbow dislocation as well as overlengthening of the prosthesis had a negative impact on the clinical outcome.

Single Modified Posterior Approach through the Space of the Proximal Radioulnar Joint for Terrible Triad Injury: A Comparative Study

Objective

In order to reduce surgical scars and the risk of neurovascular injury for the treatment of terrible triad injuries of the elbow (TTI), minimally invasive and better therapeutic effect approaches are being explored to replace the conventional combined lateral and medial approach (CLMA). This study was performed to compare the clinical effect and security of the modified posterior approach (MPA) through the space of the proximal radioulnar joint vs the CLMA for treatment of TTI.

Methods

This study retrospectively analyzed 76 patients treated for TTI from January 2009 to December 2020 (MPA: n = 44; CLMA: n = 32). Treatment involved plate and screw fixation or Steinmann pin fixation for the radial head and ulnar coronoid process fractures. Surgeons only sutured the lateral ligament because the medial collateral ligament was usually integrated in the TTI. The continuous variables were compared by the independent Student t‐test and the categorical variables by the χ²‐test or Fisher's exact test.

Results

Both groups of patients attained a satisfactory MEPS after the operation. The MEPS (MPA: 96.82 ± 6.04 vs CLMA: 96.56 ± 5.51) was not significantly different between the two groups (p > 0.05). However, the MPA resulted in better elbow flexion and extension (MPA: 123.98 ± 10.09 vs CLMA: 117.66 ± 8.29), better forearm rotation function (MPA: 173.41 ± 6.81 vs CLMA: 120.00 ± 12.18), and less intraoperative hemoglobin (MPA: 9.34 ± 5.64 vs CLMA: 16.5 ± 8.75) and red cell volume loss (MPA: 3.09 ± 2.20 vs CLMA: 6.70 ± 2.97) (All p < 0.05). Although the CLMA had a shorter surgery time (MPA: 171.73 ± 80.68 vs CLMA: 130.16 ± 71.50) (p < 0.05), it had a higher risk of neurologic damage (MPA: 0 vs CLMA: 4) (p < 0.05). Four patients developed forearm or hand numbness after the CLMA, but no patients developed numbness after the MPA. All 76 patients were followed up for 15 months postoperatively.

Conclusion

The MPA through the space of the proximal radioulnar joint has more prominent advantages than the CLMA for TTI, including single scar, clear exposure, good fixation, lower risk of neurovascular injury, and better elbow joint motion. It is a safe and effective surgical approach that is worthy of clinical promotion.

Efficacy and safety of monopolar versus bipolar radial head arthroplasty: a systematic review and meta-analysis

BACKGROUND

Radial head replacement is the main line of treating complex unstable elbow injuries. Radial head prostheses are either monopolar or bipolar. The difference between both designs in patients' clinical outcomes and postoperative complications is not yet clear. So, a systematic review and meta-analysis was conducted to evaluate the efficacy and safety of monopolar vs. bipolar implants.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane, and Scopus were searched to identify studies comparing monopolar and bipolar implants. Data on clinical outcomes, postoperative complications, revision, and removal rates were extracted.

RESULTS

Nine studies met our inclusion criteria, with a total of 591 patients (365 monopolar and 226 bipolar). Both prostheses achieved similar ranges of motion; Mayo Elbow Performance Score; Disabilities of the Arm, Shoulder, and Hand score; and visual analog scale for pain. Incidence of postoperative complications was also similar between both designs. Revision and removal rates were 24%, 8% and 29%, 14% for monopolar and bipolar implants, respectively, but no statistically significant difference could be detected.

CONCLUSIONS

No significant difference was found between monopolar and bipolar radial head prostheses in terms of efficacy and safety. Therefore, high-quality randomized controlled trials are required to determine the superiority of one design over the other.

Lateral minimal approach to the terrible triad of the elbow: a treatment protocol in Beijing Jishuitan Hospital

Background

This study aimed to report the surgical techniques and results of treating coronoid process and radial head fracture combined with dislocation of the elbow (terrible triad of the elbow) using a single lateral incision, known as the extensor digitorum communis (EDC) split approach.

Methods

A retrospective analysis was performed of 109 patients with terrible triad of the elbow who had been treated by the authors from January 2013 to December 2019. The participants included 67 males and 42 females, with a mean age of 42.2 years (14–71 years). All participants were treated via a single lateral approach. The coronoid process was fixated with Kirschner wires combined with anterior capsule suture lasso fixation. For the radial head fracture, 58 cases were fixated by AO headless cannulated screw (AO HCS) and 51 cases by acumed radial head replacement. In repair of the lateral collateral ligament (LCL) complex and the common extensor tendon, 28 cases used ETHIBOND suture through bone holes at the humeral lateral epicondyle, and the other 81 cases used suture anchors. No medial collateral ligament was repaired. A total of 46 participants were fixated with a Stryker dynamic joint distractor (DJD) II hinged external fixator to protect the bone and soft tissue.

Results

All participants were followed up from 6 to 60 months (mean, 36.1 months). Their elbow range of flexion and extension averaged 123.4°±20.7°, forearm rotation 151.0°±25.6°, and Mayo elbow performance score (MEPS) 92.3±8.8. There were 22 participants (19.5%) with ulnar nerve symptoms, 16 (14.7%) who had elbow stiffness, and 7 underwent secondary surgery, including 6 removals of internal fixation, 5 arthrolyses of the elbow, and 2 ulnar neurolyses.

Conclusions

Coronoid fractures, radial head fractures, and LCL injuries of the terrible triad of the elbow can be treated satisfactorily through a lateral minimal incision, combined with a hinged external fixation if necessary.

Mid-term clinical outcome comparison of long-stemmed monopolar osseointegrated and short-stemmed bipolar radial head prostheses

INTRODUCTION

Comparative data to guide implant choice for radial head replacements are lacking. Here, we compared the clinical results achieved using two different types of radial head prostheses.

METHODS

Data from patients with comminuted radial head fractures (n = 66), who underwent radial head arthroplasty with either short-stemmed bipolar (n = 31, Group 1: rHead Small Bone Innovations/USA) or monopolar long-stemmed osseointegrated rigidly fixed (n = 35, Group 2: MoPyC Tornier/France) prostheses, were retrospectively reviewed. Patients were followed-up for an average of 42 months (16-64 months). Range of elbow motion, elbow stability, grip strength, and visual analog scale (VAS) pain were measured, and functional outcome assessed using the Mayo Elbow Performance Score, the Disability of Arm, Shoulder and Hand questionnaire, and the Broberg-Morrey Score. Complications were analyzed and revision surgeries recorded.

RESULTS

Most patients achieved good/excellent results for all assessed outcome variables, with no significant differences between the two implant groups; however, regardless of the prosthesis type, a mean extension deficit of 18.5° ± 1.7° remained at latest follow-up. Although complication and surgical revision rates were comparable (bipolar, 23%; monopolar, 18%), significantly more bipolar prostheses were explanted because of painful loosening (16% vs. 3%; p = 0.029).

CONCLUSION

Good to excellent mid-term results for radial head arthroplasty of comminuted radial head fractures can be achieved using both a bipolar and a monopolar radial head implant; however, the monopolar implant may be preferable, as it had a lower rate of painful loosening. Extension deficit occurs regularly.

LEVEL OF EVIDENCE

Level III Retrospective comparative treatment study.

Post-traumatic elbow osteoarthritis after radial head arthroplasty: Prevalence and risk factors

BACKGROUND

One of the treatment options for comminuted radial head fractures is radial head arthroplasty (RHA), especially when the elbow is also dislocated. While the clinical outcomes of RHA have been well documented, the incidence of post-traumatic osteoarthritis after RHA and its risk factors are not well known.

OBJECTIVE

To determine the incidence of post-traumatic elbow osteoarthritis (humeroulnar and humeroradial joints) after RHA and identify its risk factors.

METHODS

All patients who underwent RHA at our hospital between 2008 and 2016 were included retrospectively. The inclusion criteria were primary RHA, recent radial head fracture (isolated or associated with elbow dislocation), minimum 1 year of follow-up, clinical and radiographic examination at final assessment. The exclusion criteria were pre-existing elbow osteoarthritis, RHA revision, multiple fractures of the ipsilateral upper limb or polytrauma. The final assessment consisted of a clinical examination [joint range of motion (ROM) and Mayo Elbow Performance Score (MEPS)] and standard radiographs. The correlation between the incidence and severity of osteoarthritis and various risk factors was determined.

RESULTS

Seventy-three patients were included in the analysis with a mean age of 56 years (21-85). The injuries consisted of 41 terrible triad, 15 isolated radial head fractures, 11 Monteggia fractures and 6 transolecranon fracture-dislocations. The mean follow-up was 3.4 years (1-10.9). At the final assessment, osteoarthritis was visible in the humeroulnar compartment in 56% of cases and in the humeroradial compartment in 72% of cases. There was a statistical correlation between the presence of humeroulnar osteoarthritis at the final assessment and ROM in flexion-extension (p=0.003), MEPS (p<0.001), duration of immobilization (p=0.03) and presence of posterior subluxation on immediate postoperative radiographs (p=0.012). The correlation between humeroradial osteoarthritis at the final assessment and ROM in flexion-extension (p=0.0054), RHA implant position (p<0.01), and unipolar configuration (p=0.027) was statistically significant.

CONCLUSION

In our study, elbow osteoarthritis incidence after RHA was 56% in the humeroulnar joint and 72% in the humeroradial joint. RHA implant placement, posterior subluxation immediately postoperative and the duration of immobilization were significantly corelated with osteoarthritis.

LEVEL OF EVIDENCE

IV; case series without control group.

Midterm outcomes of 146 EVOLVE Proline modular radial head prostheses: a systematic review

INTRODUCTION

The EVOLVE implant (Wright Medical Technology, Arlington, TN, USA) is a modular loose-fitting radial head prosthesis. The primary objective was to synthesize all available literature investigating the midterm clinical outcomes of the EVOLVE implant.

MATERIALS AND METHODS

An electronic literature search in Pubmed/Medline, Scopus, EMBASE, and Cochrane library was performed querying for studies published in 2000-2017. Articles describing clinical and radiographical outcomes as well as reoperation were included. Outcomes of interest included range of motion, Mayo Elbow Performance Score, Disabilities of the Arm Shoulder and Hand, radiographic outcome, and reason for reoperation.

RESULTS

A total of five articles consisting of 146 patients with EVOLVE implants were included. Mean patient age was 57.4 years (range 22-84), and 43.8% were males (n = 64). Mean follow-up was 4.8 years (range 1-14). Mean Mayo Elbow Performance Score and Disabilities of the Arm Shoulder and Hand score were 87.6 (range 30-100) and 18.9 (range 0-82), respectively. Midterm clinical results were good or excellent (Mayo Elbow Performance Score > 74) in 94 patients. Reoperation was observed in 12 patients, with implant revision required in 2 patients. The primary reason for reoperation was persistent stiffness (n = 9).

CONCLUSION

Midterm outcomes of EVOLVE radial head prosthesis are satisfactory, and associated complication rates are low. Loose-fit implant method appears to be a reliable approach to avoid failure of radial head prosthesis by painful loosening.

Surgical treatment of terrible triad of the elbow

Terrible triad of the elbow associates posterior dislocation, radial head fracture and coronoid process fracture. It is a complex trauma, associating severe bone and ligament lesions, with high more-or-less long-term risk of residual instability, stiffness, pain and osteoarthritis. During the last 20 years, pathologic, biomechanical and clinical knowledge has greatly progressed. Prevention of these severe complications requires initial understanding of the lesion mechanism and precise analysis of all lesions. Surgery aims to restore perfect stability by sequential anatomic repair, enabling early mobilization to prevent onset of stiffness. The aims of the present paper were to summarize the anatomic and pathophysiological bases, highlight the crucial importance of the humeroradial column and lateral collateral ligament, and to determine the importance of the coronoid process. Some aspects of treatment are controversial: systematic medial collateral ligament repair, or use of an articulated external fixator. Finally, we propose a simple algorithm to guide repair.

Downsizing effect of a modular radial head prosthesis on the lateral collateral ligament of the elbow: A cadaveric study

BACKGROUND

It remains unclear how the head and stem diameters for the radial head prosthesis could affect mechanical properties of the lateral collateral ligament measured by strain changes during elbow and forearm motions.

METHODS

Eight cadaveric specimens were secured to the device, which allows elbow flexion-extension and forearm pro-supination. Using six different implant combinations comprising 2 sizes for the head (long- and short-axis of the native head) and 3 sizes for the stem (press-fit, -1 mm, and -2 mm downsizing), prostheses were attached via the posterior approach. A differential variable reluctance transducer placed on the central portion of the radial collateral ligament were used for strain measurement with elbow flexion at 0°, 30°, 60°, and 90°. At each position, the strain patterns with the forearm in the neutral and 45° pro-supination positions were also assessed.

FINDINGS

Specimens implanted with long-axis head component showed greater increases in the ligament strain during elbow flexion than intact specimens or those implanted with short-axis head. Compared to press-fit stem, implants with downsizing to -1 mm approximated strain patterns during pro-supination with elbow extension to intact condition.

INTERPRETATION

Morphologic variation of the head and stem components in radial head prostheses led to altered strain patterns in the lateral collateral ligament during elbow and forearm motions. A short-axis head component can be used to prevent excessive strain changes after the prosthesis application. Downsizing of the stem component might be an option for approximating the biomechanics at the radiocapitellar joint during forearm rotation to the intact elbow.

Surgical treatment of the radial head is crucial for the outcome in terrible triad injuries of the elbow

AIMS

To evaluate the outcomes of terrible triad injuries (TTIs) in mid-term follow-up and determine whether surgical treatment of the radial head influences clinical and radiological outcomes.

METHODS

Follow-up assessment of 88 patients with TTI (48 women, 40 men; mean age 57 years (18 to 82)) was performed after a mean of 4.5 years (2.0 to 9.4). The Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and Disabilities of the Arm, Shoulder and Hand (DASH) score were evaluated. Radiographs of all patients were analyzed. Fracture types included 13 Mason type I, 16 type II, and 59 type III. Surgical treatment consisted of open reduction and internal fixation (ORIF) in all type II and reconstructable type III fractures, while radial head arthroplasty (RHA) was performed if reconstruction was not possible.

RESULTS

At follow-up the mean MEPS was 87.1 (20 to 100); mean OES, 36.9 (6 to 48); and mean DASH score, 18.6 (0 to 90). Mean movement was 118° (30° to 150°) for extension to flexion and 162° (90° to 180°) for pronation to supination. The overall reoperation rate was 24%, with nine ORIF, ten RHA, and two patients without treatment to the radial head needing surgical revision. When treated with RHA, Mason type III fractures exhibited significantly inferior outcomes. Suboptimal results were also identified in patients with degenerative or heterotopic changes on their latest radiograph. In contrast, more favourable outcomes were detected in patients with successful radial head reconstruction after Mason type III fractures.

CONCLUSION

Using a standardized protocol, sufficient elbow stability and good outcomes can be achieved in most TTIs. Although some bias in treatment allocation, with more severe injuries assigned to RHA, cannot be completely omitted, treatment of radial head fractures may have an independent effect on outcome, as patients subjected to RHA showed significantly inferior results compared to those subjected to reconstruction, in terms of elbow function, incidence of arthrosis, and postoperative complications. As RHA showed no apparent advantage in Mason type III injuries between the two treatment groups, we recommend reconstruction, providing stable fixation can be achieved. Cite this article: Bone Joint J 2020;102-B(12):1620-1628.

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.

Comparison of bipolar and monopolar radial head prostheses in elbow fracture-dislocation

INTRODUCTION

The role of bipolar radial head prostheses (RHP) in elbow fracture-dislocation is controversial, with some reports of poorer stabilization than with monopolar designs. The aim of the present study was to compare mono- versus bi-polar RHPs in elbow fracture-dislocation. The study hypothesis was that mono- and bi-polar RHPs do not differ in clinical and radiological results, complications or revision rates.

MATERIAL AND METHODS

A single-center retrospective study included 58 patients, with a mean age of 55 years (range, 21-84 years). All received RHP for elbow dislocation with association: terrible triad, Monteggia fracture-dislocation, transolecranal dislocation or divergent dislocation. Two groups were compared: Mono-RHP, with monopolar prosthesis (n=40), and Bi-RHP, with bipolar prosthesis (n=18). All patients underwent clinical and radiological examination at last follow-up.

RESULTS

Mean follow-up was 42.7 months (range, 12-131 months). There were no significant (p>0.05) inter-group differences in range of motion or Mayo Elbow Performance Score. Mono- versus bi-polar design did not correlate with onset of complications (p=0.89), surgical revision (p=0.71), persistent or recurrent instability (p=0.59), or ulnohumeral (p=0.62) or capitulum (p=0.159) osteoarthritis at last follow-up.

DISCUSSION AND CONCLUSION

No differences were found between mono- and bi-polar RHPs in the treatment of elbow fracture-dislocation. Clinical and radiographic results were similar, as were complications and revision rates. The literature is inconclusive, reporting contradictory conclusions. We see no contraindications to bipolar RHPs in elbow dislocation with association, notably terrible triad injury.

LEVEL OF EVIDENCE

III, Retrospective case-control study.

Contact Mechanics of Anatomic Radial Head Prosthesis: Comparison Between Native Radial Head and Anatomic Radial Head Prostheses in the Dynamic Mode

PURPOSE

The biomechanical characteristics of anatomic radial head prostheses have not been completely investigated. We compared and analyzed the contact kinematic characteristics of the native radial head and radial head prostheses replicating the native head contour, using a real-time flexion simulation model.

METHODS

Ten fresh-frozen cadavers were used in this pilot study. A simulating dynamic motion mode from 0° to 130° of elbow flexion was applied. Radiocapitellar contact pressure and area were measured using a real-time digitized pressure sensor. Further, contact area and pressure curves were obtained during flexion, using a motion-tracking device.

RESULTS

The mean contact area, mean contact pressure, and peak contact pressure of the native radial head and radial head prosthesis were 39 mm², 0.0078 kgf/mm², 0.0123 kgf/mm², and 33 mm², 0.0093 kgf/dm², 0.0148 kgf/mm², respectively. The contact area and pressure curves were parabolic nonlinear for the radial head prosthesis and more linear for the native radial head.

CONCLUSIONS

The radial head prosthesis mimics the mechanics of the native radial head in terms of mean contact area, mean contact pressure, and peak contact pressure; however, different patterns of contact pressure and area curves during elbow flexion-extension were observed.

CLINICAL RELEVANCE

We found that the biomechanics of the anatomic radial head prostheses used in the study were similar to those of the native radial head.

Risk factors of efficacy for patients receiving surgical treatment following terrible triad of the elbow joint: A comparative study

BACKGROUND

This study aims to explore the efficacy of surgical and conservative treatment for elbow joint terrible triad, and evaluate related factors affecting surgical treatment efficacy.

METHODS

Patients with terrible triad of elbow joint (n = 165) were selected, among which 79 cases underwent conservative treatment (the control group) and 86 cases underwent surgical treatment (the experimental group). The range of flexion and extension, range of rotation and Mayo elbow performance score were recorded. In the experimental group, postoperation, according to the Mayo elbow performance score, patients were assigned into the effective group (72 cases) and ineffective group (14 cases). All patients were followed up regularly for 6 to 24 months. X-ray and computed tomography examination were used to examine anterior and posterior elbow joints preoperatively and postoperatively and the degree of arm rotation.

RESULTS

The range of flexion and extension, range of rotation and Mayo elbow performance score were found to be significantly higher in the experimental group after treatment compared to the experimental group before treatment and in the control group after treatment. Seven days after treatment, compared with the control group, the expressions of interleukin (IL)-6, C-reactive protein, IL-8, and tumor necrosis factor-α in serum decreased, and returned to almost near normal levels in the experimental group. Age, mean operative time, and postoperative immobilization time were significantly different between the effective and ineffective groups. The incidence of joint stiffness, heterotopic ossification, and ulnar nerve symptoms in the effective group were lower than those in the ineffective group. The postoperative immobilization time served a protective factor for the efficacy of surgical treatment of elbow joint terrible triad, while age served as a risk factor.

CONCLUSION

The results indicated that surgical treatment regimens for elbow joint terrible triad exhibited better efficacy than conservative treatment regimens, and lower age and longer postoperative immobilization time serve as protective factors for surgical treatment efficacy.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Anthropometric Study of the Radiocapitellar Joint

PURPOSE

There is scant knowledge about the relationship between the size of the radial head and the size of the capitellum. Also, no data exist comparing the size of the capitellum between the left and the right elbow.

METHODS

Eight pairs of elbows and 12 single elbows from fresh-frozen cadavers were obtained for this study. The vertical height and anterior width of the capitellum were measured with digital calipers. Four different measurements were performed at the radial head: longest outer diameter, shortest outer diameter, the long dish diameter, and short dish diameter. The Pearson intrarater intraclass correlation coefficients were obtained for all measurements.

RESULTS

For the paired elbows, the correlations ranged between 0.95 and 0.96 for the capitellar dimensions and 0.77 and 0.98 for the radial head dimensions. The correlations between the long outer diameter of the radial head with the vertical height and the anterior width of the capitellum were 0.8 and 0.9, respectively.

CONCLUSIONS

There is a high correlation between the long outer diameter of the radial head and the vertical height of the capitellum as well its anterior width. There is also a high correlation between the left and the right elbow.

CLINICAL RELEVANCE

These findings are relevant to radiocapitellar arthroplasty and may be useful for radiocapitellar prosthetic design as well as in the preoperative planning of cases in which the radial head and/or the capitellum is destroyed.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Radial head 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.

Mid-term outcomes of 77 modular radial head prostheses

AIMS

Radial head arthroplasty (RHA) may be used in the treatment of non-reconstructable radial head fractures. The aim of this study was to evaluate the mid-term clinical and radiographic results of RHA.

PATIENTS AND METHODS

Between 2002 and 2014, 77 RHAs were implanted in 54 men and 23 women with either acute injuries (54) or with traumatic sequelae (23) of a fracture of the radial head. Four designs of RHA were used, including the Guepar (Small Bone Innovations (SBi)/Stryker; 36), Evolutive (Aston Medical; 24), rHead RECON (SBi/Stryker; ten) or rHead STANDARD (SBi/Stryker; 7) prostheses. The mean follow-up was 74.0 months (standard deviation (sd) 38.6; 24 to 141). The indication for further surgery, range of movement, mean Mayo Elbow Performance (MEP) score, quick Disabilities of the Arm, Shoulder and Hand (quickDASH) score, osteolysis and positioning of the implant were also assessed according to the design, and acute or delayed use.

RESULTS

The mean MEP and quickDASH scores were 90.2 (sd 14; 45 to 100), and 14.0 points (sd 12; 1.2 to 52.5), respectively. There were no significant differences between RHA performed in acute or delayed fashion. There were 30 re-operations (19 with, and 11 without removal of the implant) during the first three post-operative years. Painful loosening was the primary indication for removal in 14 patients. Short-stemmed prostheses (16 mm to 22 mm in length) were also associated with an increased risk of painful loosening (odds ratio 3.54 (1.02 to 12.2), p = 0.045). Radiocapitellar instability was the primary indication for re-operation with retention of the implant (5). The overall survival of the RHA, free from re-operation, was 60.8% (sd 5.7%) at ten years.

CONCLUSION

Bipolar and press-fit RHA gives unsatisfactory mid-term outcomes in the treatment of acute fractures of the radial head or their sequelae. The outcome may vary according to the design of the implant. The rate of re-operation during the first three years is predictive of the long-term survival in tight-fitting RHAs. Cite this article: Bone Joint J 2017;99-B1197-1203.

Radial Head Ingrowth Anatomic Implant Versus Smooth Stem Monoblock Implant in Acute Terrible Triad Injury: A Prospective Comparative Study

OBJECTIVE

This study aimed to compare clinical outcomes and radiographic findings between patients who received 2 different implants (smooth-stemmed modular implant or an anatomic press-fit implant) on patients with acute terrible triad injuries.

DESIGN

Prospective cohort.

SETTING

Level II Trauma center, University hospital.

PATIENTS/PARTICIPANTS

Thirty-four patients with an isolated terrible triad injury were divided into 2 study groups (n = 17 each) with different sets of radial head implants and followed for 2 years. A total of 14 patients in each group (n = 28) completed the study.

INTERVENTION

Group 1 received a smooth-stemmed round modular monopolar implant. Group 2 received an in-growth modular monopolar press-fit anatomic implant.

MAIN OUTCOME MEASUREMENTS

Clinical outcomes were evaluated using the Visual Analog Scale, Mayo Index, and Disabilities of the Arm, Shoulder, and Hand (DASH) survey. Radiographs were evaluated for ectopic bone formation and loosening.

RESULTS

No difference in clinical outcome when comparing range of motion and functionally scores between groups. Ectopic bone formation occurred equally with implants. Bone formation at the proximal radius under the implant occurred more in group 1 (85.7%), (P = 0.046). Five press-fit stems had radiolucent lines at 2-year follow-up. Two were removed because of symptomatic loosening.

CONCLUSIONS

Short-term outcomes for both implants showed to be equally effective treatment options. The in vitro biomechanical advantages of anatomic implants do not translate into short-term improved outcomes. Symptomatic aseptic loosening in anatomic implants is common. Bone formation at the proximal radial neck was observed more with smooth-stemmed implants; further studies should assess this findings and clinical implication.

LEVEL OF EVIDENCE

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

Radial Neck Dilatory Remodeling After Radial Head Arthroplasty With an Uncemented, Press Fit, Fully Chemically Etched Stem Design

OBJECTIVES

To compare the radiographic outcomes of 2 widely used side loading, press fit, RHA implants used to reconstruct complex elbow trauma.

DESIGN

Retrospective cohort study.

SETTING

Level-1 Academic trauma center.

PARTICIPANTS

Patients undergoing RHA.

INTERVENTION

Cohort 1 received Synthes Radial Head Prosthesis. Cohort 2 received Biomet ExploR Radial Head Replacement.

MAIN OUTCOME MEASUREMENTS

Radial neck dilatory remodeling.

RESULTS

Eighty-two subjects were included in final analysis, 63 from the Biomet Cohort, and 19 from Synthes cohort. Demographic and injury characteristics were similar among cohorts. Radial neck dilatory remodeling as well as periprosthetic radiographic lucency were seen significantly more frequently and to a significantly greater degree in the Synthes cohort. The average percentage of dilatory remodeling of the Synthes cohort was 34.9% and that of the Biomet cohort was 2.7%. There were no differences in rates of revision surgery.

CONCLUSIONS

Our study demonstrates significant radiographic differences between 2 frequently used RHA implants. Radial neck dilatory remodeling is a common, rapidly progressive, and dramatic finding frequently seen with the Synthes Radial Head Prosthesis.

LEVEL OF EVIDENCE

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

Radial Head Arthroplasty in the Active Duty Military Service Member With Minimum 2-Year Follow-Up

PURPOSE

Radial head arthroplasty (RHA) is a viable treatment for complex radial head fracture. Whereas elbow stability and function is typically restored at short- to mid-term follow-up, the outcome in higher-demand populations is not well defined. We sought to characterize the functional and occupational outcomes following RHA in an active duty military population with intense upper extremity demands.

METHODS

We retrospectively reviewed the records of all U.S. military service members undergoing primary RHA from 2010 and 2013 with a minimum of 2-year follow-up. Patient-based, injury-related, and surgical variables were extracted from the military-wide electronic medical record. Functional and occupational outcomes including pain, and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire were recorded. The primary outcomes of interest were the rate and level of return to upper extremity activity. Secondary outcome measures included return to duty, complications, and revision surgery.

RESULTS

Nineteen patients were included with average age 31 years and median 37 months' follow-up. Ten were Mason III, 6 were part of a terrible triad injury, and the remainder were fracture-dislocations. At an average follow-up of 3.7 years, 15 patients returned to active military duty, and 9 resumed their regular upper extremity military function. At the time of final follow-up, the average DASH score was 13. Seven patients returned to their usual level of sport and exercise, 6 at a reduced level, and 6 did not resume physical exercises secondary to pain or stiffness. Sixteen adverse outcomes among 14 patients included symptomatic heterotopic ossification (5 of 19) and neurological sequelae (4 of 19). Three elected to have a revision procedure at an average of 13 months for heterotopic ossification or loosening.

CONCLUSIONS

Among active patients with radial head fractures treated with RHA, three-quarters will return to active duty military service, push-ups, and sport; however, half may report an adverse outcome unrelated to the prosthesis and only about half of patients will return to their preinjury level of function.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Radiocapitellar contact characteristics during prosthetic radial head subluxation

BACKGROUND

Metallic radial head prostheses are often used in the management of comminuted radial head fractures and elbow instability. We hypothesized that during radiocapitellar subluxation, the contact pressure characteristics of an anatomic radial head prosthesis will more closely mimic those of the native radial head compared with a monopolar circular or a bipolar circular radial head design.

MATERIALS AND METHODS

With use of 6 fresh frozen cadaver elbows, mean radiocapitellar contact pressures, contact areas, and peak pressures of the native radial head were assessed at 0, 2, 4, and 6 mm of posterior subluxation. These assessments were repeated after the native radial head was replaced with anatomic, monopolar circular and bipolar circular prostheses.

RESULTS

The joint contact pressures increased with the native and the prosthetic radial head subluxation. The mean contact pressures for the native radial head and anatomic prosthesis increased progressively and significantly from 0 to 6 mm of subluxation (native, 0.6 ± 0.0 MPa to 1.9 ± 0.2 MPa; anatomic, 0.7 ± 0.0 MPa to 2.1 ± 0.3 MPa; P < .0001). The contact pressures with the monopolar and bipolar prostheses were significantly higher at baseline and did not change significantly further with subluxation (monopolar, 2.0 ± 0.1 MPa to 2.2 ± 0.2 MPa [P = .31]; bipolar, 1.7 ± 0.1 MPa to 1.9 ± 0.1 MPa [P = .12]). The pattern of increase in contact pressures with the anatomic prosthesis mimicked that of the native radial head. Conversely, the circular prostheses started out with higher contact pressures that stayed elevated.

CONCLUSION

The articular surface design of a radial head prosthesis is an important determinant of joint contact pressures.

Risk of Subluxation or Dislocation After Operative Treatment of Terrible Triad Injuries

OBJECTIVE

The management of terrible triad injuries has evolved over the last 2 decades to include routine radial head fixation or replacement, reattachment of the lateral collateral ligament, with or without coronoid fixation. Our objective was to determine the likelihood of and factors associated with subluxation or dislocation after operative treatment of terrible triad injuries among a large group of surgeons using current techniques.

DESIGN

Retrospective cohort study.

SETTING

Two level I trauma centers.

PATIENTS/PARTICIPANTS

A total of 107 patients with operatively treated terrible triad injuries from January 2000 to June 2015.

INTERVENTION

Review of patient- and surgery-related factors during the first postoperative month.

MAIN OUTCOME MEASUREMENT

Radiographic subluxation of the ulnohumeral joint.

RESULTS

One hundred of the 107 patients (93%) treated with open fixation of terrible triad injuries had no radiographic subluxation or redislocation. Two patients (2%) had slight transient radiographic subluxation ("drop sign") that corrected with active exercises within weeks of surgery. Five patients (5%) had persistent radiographic subluxation, 3 treated with a second surgery (3%). When treated within 2 weeks of injury, recurrent subluxation or dislocation after operative fixation of terrible triad injuries was rare (1%), provided that the radial head was replaced and the lateral collateral ligament reattached.

CONCLUSIONS

Radiographic subluxation is very uncommon with current operative management of terrible triad injuries of the elbow within 2 weeks. Patients treated more than 2 weeks after injury might benefit from ancillary fixation to limit subluxation (ie, cross pinning, external fixation, or internal joint stabilizer).

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

[Primary radial head arthroplasty in trauma : Complications]

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

Press-fit bipolar radial head arthroplasty, midterm results

BACKGROUND

Theoretical advantages of bipolar compared with monopolar radial head arthroplasty include better accommodation of radiocapitellar malalignment, reduction of capitellar abrasion, and reduction of stress at the bone-implant interfaces. Our purpose was to report the midterm results of press-fit bipolar radial head arthroplasty.

METHODS

Thirty patients were treated by press-fit bipolar radial head arthroplasty for acute fracture of the radial head, failed earlier treatment, or post-traumatic sequelae. Three patients were lost to follow-up. Results are presented for the remaining 27 patients.

RESULTS

At mean follow-up of 48 months (range, 28-73), there had been 3 (11%) revisions. Two involved conversion to prosthetic radiocapitellar hemiarthroplasty for symptomatic capitellar abrasion; a third involved exchange of the articular component (ie, head) for instability. In all, the stems appeared well fixed. A prosthesis in a subluxed position accounted for the 1 (4%) additional radiologic failure. The average flexion-extension arc was 136° (range, 120°-145°), and the average pronation-supination arc was 138° (range, 70°-180°). According to the Mayo Elbow Performance Score, the combined excellent and good results accounted for 70%.

CONCLUSIONS

The overall midterm outcome of this series of 30 press-fit bipolar radial head arthroplasties can be considered favorable. Although the revision rate was 11%, the stems were well fixed in all. There was 1 (4%) additional radiologic failure. We suggest considering a press-fit bipolar radial head prosthesis for acute comminuted radial head fractures with limited bone loss of the proximal radius.

Radial head replacement in adults with recent fractures

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

The effect of capitellar impaction fractures on radiocapitellar stability

PURPOSE

To determine the effect of capitellar impaction fractures on radiocapitellar stability in a model that simulated a terrible triad injury.

METHODS

Six cadaveric elbows were dissected free of skin and muscles. Tendons were preserved. The lateral collateral ligament was released and repaired (surgical control). Two sizes of capitellar impaction defects were created. After lateral collateral ligament release and repair, we then sequentially created osseous components of a terrible triad injury (partial radial head resection and coronoid fracture) through an olecranon osteotomy that was fixed with a plate. Radiocapitellar stability was recorded after the creation of each new condition.

RESULTS

Significantly less force was required for radiocapitellar subluxation after the creation of 20° and 40° capitellar defects compared with the surgical control (intact capitellum). After the addition of a Mason type II radial head defect and then a coronoid defect, stability decreased significantly further.

CONCLUSIONS

Impaction fractures of the distal portion of the capitellum may contribute to a loss of radiocapitellar stability, particularly in an elbow fracture-dislocation.

CLINICAL RELEVANCE

Because these injuries may be unrecognized, consideration should be given to diagnosing and addressing them.

Radial head arthroplasty: state of the art

Radial head arthroplasty has joined the armamentarium of options for the treatment of complex radial head fractures, elbow instability, and arthritic conditions. A variety of implants has been introduced in the past decade; these differ in metallic composition, design, and method of fixation. Good short- and intermediate-term outcomes have been reported with the use of loose-fitting prostheses. Press-fit devices restore stability and improve pain and motion but are associated with a greater likelihood of implant loosening, leading to revision surgery. Postoperative elbow stiffness, pain, ulnar nerve palsy, posterior interosseous nerve palsy, and heterotopic ossification have all been reported following radial head surgery, but these complications are likely related to the trauma sustained by the elbow. Adequate knowledge of the surgical indications, types of implants, and surgical technique are essential for a satisfactory outcome when a radial head prosthesis is used for the treatment of nonreconstructable radial head fractures.

Nonacute Treatment of Elbow Fracture with Persistent Ulnohumeral Dislocation or Subluxation

➤ There are patterns of traumatic elbow instability that help a surgeon to anticipate which structures are injured.➤ Patients treated for persistent subluxation or dislocation of the elbow more than two weeks after injury regain less motion and experience more adverse events.➤ The primary goal of treatment is stable reduction of the ulnohumeral joint and functional elbow motion.➤ Motion and pain are affected by contracture and scarring of the soft tissues, malalignment of the joint, fracture malunion, damage to the articular surface, and ulnar neuropathy.➤ Biomechanical and clinical studies support treatment with radial head arthroplasty and/or coronoid reconstruction for patients who have osseous insufficiency.

Single-staged treatment using a standardized protocol results in functional motion in the majority of patients with a terrible triad elbow injury

BACKGROUND

Terrible triad injuries of the elbow, defined as elbow dislocation with associated fractures to the radial head and coronoid, are associated with stiffness, pain, and loss of motion. Studies to date have consisted of small sample sizes and used heterogeneous surgical techniques, which render comparisons difficult and unreliable.

QUESTIONS/PURPOSES

In a group of patients treated under a standard surgical protocol, we sought to determine the early dislocation rate, the range of motion in those not undergoing secondary procedures, the frequency and types of secondary surgical interventions required, the difference in motion between those undergoing secondary surgery and those who did not, and the frequency of heterotopic ossification and patient-reported stiffness.

METHODS

Patients underwent a surgical protocol that involved fixing the coronoid, fixing the radial head if possible, otherwise performing radial head arthroplasty, and repairing the lateral ligamentous structures. Patients were excluded if ipsilateral upper extremity fractures from the humerus to the distal forearm were present. Fifty-two patients had a minimum followup of 6 weeks and were included for the early dislocation rate, and 34 of these (65%) had a minimum of 6 months followup and were included for the rest of the data. Eighteen of the 52 (35%) were considered lost to followup because they were seen for less than 6 months postsurgically and were excluded from further analysis. Chart review was performed to determine the presence of early dislocation within the first 6 weeks after surgery, range of motion in patients not requiring a secondary procedure, the frequency and types of secondary procedures required, the range of motion before and after a secondary procedure if it was required, and postoperative stiffness. Postoperative radiographs were analyzed to determine the presence and severity of heterotopic ossification.

RESULTS

One of 52 patients sustained a dislocation within the first weeks of surgery (1.9%). Those not undergoing a secondary procedure were able to achieve a flexion arc of 110° and a supination-pronation arc of 148°. Nine of 34 patients (26%) underwent a secondary surgical procedure with stiffness, heterotopic ossification, and ulnar neuropathy being the most common surgical indications. Before secondary surgical procedures, patients had a flexion arc of 57° and a supination-pronation arc of 55°, which was less than those only requiring primary surgery alone (p < 0.001). After secondary surgery, patients were able to achieve a flexion arc of 96° and a supination-pronation arc of 124°, which was not different from those who did not undergo reoperation (p = 0.09 and p = 0.08, respectively). Twenty-eight of 34 patients demonstrated evidence of heterotopic ossification on radiographs, whereas 20 patients, including all nine undergoing secondary procedures, reported stiffness at the elbow.

CONCLUSIONS

Using a standardized surgical protocol, a low early dislocation rate was observed, although stiffness remains a challenge. Many patients who initially do not attain functional range of motion can usually attain this after secondary procedures aimed at removing the heterotopic ossification.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See guidelines for authors for a complete description of levels of evidence.

Radial head reconstruction in elbow fracture-dislocation: monopolar or bipolar prosthesis?

BACKGROUND

Monopolar and bipolar radial head prosthetic arthroplasties have been used successfully to treat elbow fracture-dislocation with unsalvageable radial head fractures. The relative stability of these two designs in different clinical situations is a topic of ongoing investigation.

QUESTIONS/PURPOSES

We tested the effects of monopolar and bipolar fixed-neck prosthetic radial head implants on improvement in elbow coronal and axial plane laxity in a terrible triad biomechanical model that accounted for lateral collateral ligament integrity and the presence of a transverse coronoid fracture.

METHODS

Kinematic data were collected on six fresh-frozen cadaveric upper extremities tested with passive motion throughout the flexion arc. Varus and valgus gravity stress were applied with the wrist in neutral position. A lateral collateral ligament reconstruction was simulated. We assessed instability after radial head resection and reconstruction with either a monopolar or bipolar implant in the presence of a transversely fractured (Regan and Morrey Type 2) or fixed coronoid process.

RESULTS

With collateral ligament integrity, no difference was detected, with the numbers available, in valgus laxity between implants under valgus stress (p = 1.0). Laxity improvement with each prosthesis was higher when the coronoid was fractured (mean ± SD: monopolar: 7.4° ± 1.6°, p < 0.001; bipolar: 6.4° ± 1.6°, p = 0.003) than when it was fixed (monopolar: 4.0° ± 1.6°, p = 0.02; bipolar: 4.2° ± 1.6°, p = 0.01). With the numbers available, there was no difference in external rotation laxity between implants under valgus stress (p = 1.0). The greatest stabilizing effect of the prostheses occurred when the coronoid was fractured (monopolar: 3.3° ± 1.2°, p = 0.15; bipolar: 3.3° ± 1.2°, p = 0.17). Radial head arthroplasty offered no substantial stability under varus stress for varus or internal rotation laxity.

CONCLUSIONS

In our terrible triad cadaveric model, coronoid fixation was effective in improving varus laxity with a monopolar or bipolar prosthesis in place. Also, both types of prostheses were effective in improving valgus and external rotation laxity to the elbow, regardless of coronoid status. With collateral ligaments reconstructed, no large kinematic differences were noted between implants regardless of the varus-valgus position or whether the coronoid was fractured or fixed.

CLINICAL RELEVANCE

The data from our cadaveric model support the use of either implant type in terrible triad injuries if the collateral ligaments are intact or reconstructed.

[Endoprosthetics of acute radial head fractures]

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