A hinged external fixator for complex elbow dislocations: a multicenter prospective cohort study

Safety and effectiveness of the three-dimensional-printed guide plate-assisted rotation axis positioning of a hinged external fixator for the elbow

PURPOSE

We aimed to evaluate the safety and effectiveness of three-dimensional (3D)-printed guide plates for assisting in the positioning of the rotation axis of an elbow-hinged external fixator.

METHODS

Terrible triad (TT) patients, who were screened using the predefined inclusion and exclusion criteria, underwent installation of a hinged external fixator on the basis of internal fixation; 3D-printed guide plates, generated from the patient's imaging data, assisted in positioning the rotation axis. All patients received the same peri-operative management and were followed up at six, 12, 24, and 48 weeks postoperatively. The duration of positioning pin placement, the number of fluoroscopies, pin placement success rate, types and incidence of post-operative complications, and the Mayo elbow performance score (MEPS) of the diseased elbow and range of motion (ROM) of both elbows were assessed.

RESULTS

In 25 patients who completed the follow-up, the average time required for positioning pin placement was 329.32 ± 42.38 s (263-443 s), the average number of fluoroscopies was 2.32 ± 0.48 times (2-3 times), and the pin placement success rate was 100%. At the last follow-up, the mean MEPS of the diseased elbow was 97.50 ± 6.92 (75-100), with an excellent and good rate of 100%, and all patients demonstrated stable concentric reduction. The average range of flexion and extension was 135.08° ± 17.10° (77-146°), while the average range of rotation was 169.21° ± 18.14° (108-180°). No significant difference was observed in the average ROM between the both elbows (P > 0.05). Eight (32%) patients developed post-operative complications, including elbow stiffness due to heterotopic ossification in three (12%) patients, all of whom did not require secondary intervention.

CONCLUSION

Utilizing 3D-printed guide plates for positioning the rotation axis of an elbow-hinged external fixator significantly reduced intra-operative positioning pin placement time and the number of fluoroscopies with excellent positioning results. Satisfactory results were also obtained in terms of post-operative complications, elbow ROM, and functional scores.

The Role of External Fixation in the Management of Upper Extremity Fractures

External fixation is a powerful tool in the armamentarium of the active orthopaedic surgeon. The upper extremity, however, poses unique challenges in the techniques of external fixation because of the smaller soft-tissue envelope and the proximity of neurovascular structures, which may be entrapped in fracture fragments or traversing in line with pin trajectories. This review article summarizes the indications, techniques, clinical outcomes, and complications of external fixation of the upper extremity in the setting of proximal humerus, humeral shaft, distal humerus, elbow, forearm, and distal radius fractures.

Complications and range of motion of patients with an elbow dislocation treated with a hinged external fixator: a retrospective cohort study

PURPOSE

Elbow dislocations are at risk for persistent instability and stiffness of the joint. Treatment with a hinged external fixation provides elbow joint stability, and allows early mobilization to prevent stiffness. Mounting a hinged elbow fixator correctly, however, is technically challenging. The low incidence rate of elbow dislocations with persistent instability suggests that centralization would result in higher surgeon exposure and consequently in less complications. This study aimed to investigate the results of treatment of elbow dislocations with a hinged elbow fixator on the rate of complications, range of motion, level of pain and restrictions in activities of daily living.

METHODS

A retrospective observational cohort study in a level I trauma center, in which the majority of patients was treated by a dedicated elbow surgeon, was performed. All patients of 16 years or older treated with a hinged external elbow fixator between January 1, 2006 and December 31, 2017 were included. The fixator could be used (1) for the treatment of persistent instability in acute/residual simple and complex dislocations or (2) as revision surgery to treat joint incongruency or a stiff elbow. Patient and injury characteristics, details on treatment, complications, secondary interventions, and range of motion were extracted from the patients' medical files.

RESULTS

The results of treatment of 34 patients were analyzed with a median follow-up of 13 months. The fixator was removed after a median period of 48 days. Fixator-related complications encountered were six pintract infections, one redisclocation, one joint incongruency, one muscle hernia, and one hardware failure. The median range of motion at the end of follow-up was 140° flexion, 15° constraint in extension, 90° pronation, and 80° supination.

CONCLUSION

A hinged elbow fixator applied by a dedicated elbow surgeon in cases of elbow instability after elbow dislocations can result in excellent joint function. Fixator-related complications are mostly mild and only temporary.

A comparative study on the validity and reliability of anterior, medial, and posterior approaches for internal fixation in the repair of fractures of the coronoid process of the ulna

Background

The coracoid process plays an important role in maintaining the stability of the elbow joint. A fracture of the coronoid process is often treated via surgical approaches, including open reduction and internal fixation, which aim to regain a stable, flexible, and loadable joint. In this study, we compared the anterior, medial, and posterior approaches of internal fixation in the repair of fractures of the coronoid process of the ulna.

Methods

In this retrospective study, 147 patients with fractures in the coronoid process of the ulna were recruited and classified into the anterior group (n = 73), the medial group (n = 32), and the posterior group (n = 42) according to the surgical approach used for internal fixation. These patients were assessed with respect to incision, operative time, estimated blood loss, fracture healing, and postoperative complications. The Mayo Elbow Performance Score was used to evaluate any form of disability associated with elbow injuries. Multivariate logistic regression analysis was performed to investigate the factors influencing the efficacy of fractures of the coronoid process of the ulna.

Results

In the medial approach group, the operative time was longer, and perioperative blood loss and postoperative drainage volume were obviously increased compared with the anterior and posterior groups. The anterior group exhibited a better postoperative recovery compared with the medial, and posterior groups. Compared with the anterior group, fracture-healing time in the posterior group was further reduced, whereas elbow joint flexion extension and forearm rotation degree improved. Complications were significantly reduced in the posterior approach group compared with the anterior and medial groups. The factors influencing the efficacy of fractures of the coronoid process of the ulna included the Regan–Morrey classification, perioperative blood loss, and the internal fixation approach.

Conclusion

In summary, the approach used influences fracture healing or the outcome after osteosynthesis. The posterior internal fixation method produced satisfactory functional outcomes in patients with fractures of the coronoid process of the ulna.

Validation of the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale Dutch language version in patients with hindfoot fractures

OBJECTIVES

The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale is among the most used questionnaires for measuring functional recovery after a hindfoot injury. Recently, this instrument was translated and culturally adapted into a Dutch version. In this study, the measurement properties of the Dutch language version (DLV) were investigated in patients with a unilateral hindfoot fracture.

DESIGN

Multicentre, prospective observational study.

SETTING

This multicentre study was conducted in three Dutch hospitals.

PARTICIPANTS

In total, 118 patients with a unilateral hindfoot fracture were included. Three patients were lost to follow-up.

PRIMARY AND SECONDARY OUTCOME MEASURES

Patients were asked to complete the AOFAS-DLV, the Foot Function Index and the Short Form-36 on three occasions. Descriptive statistics (including floor and ceiling effects), reliability (ie, internal consistency), construct validity, reproducibility (ie, test-retest reliability, agreement and smallest detectable change (SDC)) and responsiveness were determined.

RESULTS

Internal consistency was inadequate for the AOFAS-DLV total scale (α=0.585), but adequate for the function subscale (α=0.863). The questionnaire had adequate construct validity (82.4% of predefined hypotheses were confirmed), but inadequate longitudinal validity (70.6%). No floor effects were found, but ceiling effects were present in all AOFAS-DLV (sub)scales, most pronounced from 6 to 24 months after trauma onwards. Responsiveness was only adequate for the pain and alignment subscales, with a SDC of 1.7 points.

CONCLUSIONS

The AOFAS Ankle-Hindfoot Scale DLV has adequate construct validity and is reliable, making it a suitable instrument for cross-sectional studies investigating functional outcome in patients with a hindfoot fracture. The inadequate longitudinal validity and responsiveness, however, hamper the use of the questionnaire in longitudinal studies and for assessing long-term functional outcome.

TRIAL REGISTRATION NUMBER

NTR5613; Post-results.

The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale; translation and validation of the Dutch language version for ankle fractures

OBJECTIVES

The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale is among the most commonly used instruments for measuring outcome of treatment in patients who sustained a complex ankle or hindfoot injury. It consists of a patient-reported and a physician-reported part. A validated, Dutch version of this instrument is currently not available. The aim of this study was to translate the instrument into Dutch and to determine the measurement properties of the AOFAS Ankle-Hindfoot Scale Dutch language version (DLV) in patients with a unilateral ankle fracture.

SETTING

Multicentre (two Dutch hospitals), prospective observational study.

PARTICIPANTS

In total, 142 patients with a unilateral ankle fracture were included. Ten patients were lost to follow-up.

PRIMARY AND SECONDARY OUTCOME MEASURES

Patients completed the subjective (patient-reported) part of the AOFAS Ankle-Hindfoot Scale-DLV. A physician or trained physician-assistant completed the physician-reported part. For comparison and evaluation of the measuring characteristics, the Foot Function Index and the Short Form-36 were completed by the patient. Descriptive statistics (including floor and ceiling effects), reliability (ie, internal consistency), construct validity, reproducibility (ie, test-retest reliability, agreement and smallest detectable change) and responsiveness were determined.

RESULTS

The AOFAS-DLV and its subscales showed good internal consistency (Cronbach's α >0.90). Construct validity and longitudinal validity were proven to be adequate (76.5% of predefined hypotheses were confirmed). Floor effects were not present. Ceiling effects were present from 6 months onwards, as expected. Responsiveness was adequate, with a smallest detectable change of 12.0 points.

CONCLUSIONS

The AOFAS-DLV is a reliable, valid and responsive measurement instrument for evaluating functional outcome in patients with a unilateral ankle fracture. This implies that the questionnaire is suitable to compare different treatment modalities within this population or to compare outcome across hospitals.

TRIAL REGISTRATION

The Netherlands Trial Register (NTR5613; 05-jan-2016).

Accuracy in identifying the elbow rotation axis on simulated fluoroscopic images using a new anatomical landmark

External fixation of the elbow requires identification of the elbow rotation axis, but the accuracy of traditional landmarks (capitellum and trochlea) on fluoroscopy is limited. The relative distance (RD) of the humerus may be helpful as additional landmark. The first aim of this study was to determine the optimal RD that corresponds to an on-axis lateral image of the elbow. The second aim was to assess whether the use of the optimal RD improves the surgical accuracy to identify the elbow rotation axis on fluoroscopy. CT scans of elbows from five volunteers were used to simulate fluoroscopy; the actual rotation axis was calculated with CT-based flexion–extension analysis. First, three observers measured the optimal RD on simulated fluoroscopy. The RD is defined as the distance between the dorsal part of the humerus and the projection of the posteromedial cortex of the distal humerus, divided by the anteroposterior diameter of the humerus. Second, eight trauma surgeons assessed the elbow rotation axis on simulated fluoroscopy. In a preteaching session, surgeons used traditional landmarks. The surgeons were then instructed how to use the optimal RD as additional landmark in a postteaching session. The deviation from the actual rotation axis was expressed as rotational and translational error (±SD). Measurement of the RD was robust and easily reproducible; the optimal RD was 45%. The surgeons identified the elbow rotation axis with a mean rotational error decreasing from 7.6° ± 3.4° to 6.7° ± 3.3° after teaching how to use the RD. The mean translational error decreased from 4.2 ± 2.0 to 3.7 ± 2.0 mm after teaching. The humeral RD as additional landmark yielded small but relevant improvements. Although fluoroscopy-based external fixator alignment to the elbow remains prone to error, it is recommended to use the RD as additional landmark.

Complex elbow instability: surgical management of elbow fracture dislocations

There are three main patterns of complex elbow instability: posterolateral (terrible triad), varus posteromedial (anteromedial coronoid fracture with lateral collateral ligament complex disruption), and trans-olecranon fracture dislocations.Radial head fractures, in the setting of complex elbow instability, often require internal fixation or arthroplasty; the outcome of radial head replacement is dictated by adequate selection of the head diameter, correct restoration of radial length, and proper alignment and tracking.Small coronoid fractures can be ignored. Larger coronoid fractures, especially those involving the anteromedial facet, require fixation or graft reconstruction, particularly in the presence of incongruity.The lateral collateral ligament complex should be repaired whenever disrupted. Medial collateral ligament disruptions seem to heal reliably without surgical repair provided all other involved structures are addressed.The most common mistakes in the management of trans-olecranon fracture dislocations are suboptimal fixation, lack of fixation of coronoid fragments, and lack of restoration of the natural dorsal angulation of the ulna. Cite this article: Sanchez-Sotelo J, Morrey M. Complex elbow instability. EFORT Open Rev 2016;1:183-190.

American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score: a study protocol for the translation and validation of the Dutch language version

INTRODUCTION

The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score is among the most commonly used instruments for measuring the outcome of treatment in patients who sustained a complex ankle or hindfoot injury. It combines a clinician-reported and a patient-reported part. A valid Dutch version of this instrument is currently not available. Such a translated and validated instrument would allow objective comparison across hospitals or between patient groups, and with shown validity and reliability it may become a quality of care indicator in future. The main aims of this study are to translate and culturally adapt the AOFAS Ankle-Hindfoot Score questionnaire into Dutch according to international guidelines, and to evaluate the measurement properties of the AOFAS Ankle-Hindfoot Score-Dutch language version (DLV) in patients with a unilateral ankle or hindfoot fracture.

METHODS AND ANALYSIS

The design of the study will be a multicentre prospective observational study (case series) in patients who presented to the emergency department with a unilateral ankle or hindfoot fracture or (fracture) dislocation. A research physician or research assistant will complete the AOFAS Ankle-Hindfoot Score-DLV based on interview for the subjective part and a physical examination for the objective part. In addition, patients will be asked to complete the Foot Function Index (FFI) and the Short Form-36 (SF-36). Descriptive statistics (including floor and ceiling effects), internal consistency, construct validity, reproducibility (ie, test-retest reliability, agreement and smallest detectable change) and responsiveness will be assessed for the AOFAS DLV.

ETHICS AND DISSEMINATION

This study has been exempted by the Medical Research Ethics Committee (MREC) Erasmus MC (Rotterdam, the Netherlands). Each participant will provide written consent to participate and remain anonymised during the study. The results of the study are planned to be published in an international, peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NTR5613. pre-result.

Management of post-traumatic elbow instability after failed radial head excision: A case report

Radial head excision has always been a safe commonly used surgical procedure with a satisfactory clinical outcome for isolated comminuted radial head fractures. However, diagnosis of elbow instability is still very challenging and often underestimated in routine orthopaedic evaluation. We present the case of a 21-years old female treated with excision after radial head fracture, resulting in elbow instability. The patient underwent revision surgery after four weeks. We believe that ligament reconstruction without radial head substitution is a safe alternative choice for Mason III radial head fractures accompanied by complex ligament lesions.

Application of distal radius-positioned hinged external fixator in complete open release for severe elbow stiffness

BACKGROUND

Radical release for severe stiff elbows may lead to instability. Hinged external fixation is used to treat unstable elbows. We hypothesized that extensive open release combined with a distal radius-positioned hinged external fixator would have good performance and low complications rate in treating severe elbow stiffness. Thus, the efficacy and security of this technique were assessed in this study.

METHODS

We retrospectively reviewed 38 post-traumatic elbows with severe stiffness that underwent arthrolysis between February 2011 and February 2014. All patients were assessed as having elbow instability after complete arthrolysis. Ligament repair was combined with implantation of a hinged external fixator (fixed to the humerus and distal radius) to maintain elbow stability. Flexion arc, forearm rotation, Mayo Elbow Performance Score, elbow stability, and radiographs were evaluated preoperatively and postoperatively, and complications were documented.

RESULTS

Mean follow-up was 31 months. Significant improvement was noted in flexion-extension arc (from 27° to 126°), forearm rotation (from 148° to 153°), and mean Mayo Elbow Performance Score (from 68 points to 96 points). Mean pronation arc decreased from 66° preoperatively to 6° at 1.5 months of follow-up and showed a transient reduction during first 6 months postoperatively. Pin-related infection occurred in 2 patients, which was cured with conservative treatment. Two patients had moderate instability after removal of the fixator and regained stability at the 12-month follow-up. At the last follow-up, complications included ulnar nerve paralysis in 3, recurrence of heterotopic ossification in 1, and moderate pain in 1.

CONCLUSIONS

Complete open release combined with a distal radius-positioned hinged external fixator is an effective treatment for severe stiff elbows. This technique had a low complication rate.

Functional recovery after treatment of extra-articular distal radius fractures in the elderly using the IlluminOss® System (IO-Wrist); a multicenter prospective observational study

BACKGROUND

Approximately 17 % of all fractures involve the distal radius. Two-thirds require reduction due to displacement. High redislocation rates and functional disability remain a significant problem after non-operative treatment, with up to 30 % of patients suffering long-term functional restrictions. Whether operative correction is superior to non-operative treatment with respect to functional outcome has not unequivocally been confirmed. The IlluminOss® System was introduced in 2009 as a novel, patient-specific, and minimally invasive intramedullary fracture fixation. This minimally invasive technique has a much lower risk of iatrogenic soft tissue complications. Because IlluminOss® allows for early mobilization, it may theoretically lead to earlier functional recovery and ADL independence than non-operative immobilization. The main aim of this study is to examine outcome in elderly patients who sustained a unilateral, displaced, extra-articular distal radius fracture that was treated with IlluminOss®.

METHODS/DESIGN

The design of the study will be a multicenter, prospective, observational study (case series). The study population comprises elderly (60 years or older; independent in activities of daily living) with a unilateral, displaced, extra-articular distal radius fracture (AO/OTA type 23-A2 and A3) that after successful closed reduction was fixed within 2 weeks after the injury with IlluminOss®. Critical elements of treatment will be registered, and outcome will be monitored until 1 year after surgery. The Disabilities of the Arm, Shoulder, and Hand score will serve as primary outcome measure. The Patient-Rated Wrist Evaluation score, level of pain, health-related quality of life (Short Form-36 and EuroQoL-5D), time to ADL independence, time to activities/work resumption, range of motion of the wrist, radiological outcome, and complications are secondary outcome measures. Health care consumption and lost productivity will be used for a cost analysis. The cost analysis will be performed from a societal perspective. Descriptive data will be reported.

DISCUSSION

The results of this study will provide evidence on the effectiveness of operative treatment of patients who sustained an extra-articular distal radius fracture with the IlluminOss® System, using clinical, patient-reported, and societal outcomes.

TRIAL REGISTRATION

The study is registered at the Netherlands Trial Register ( NTR5457 ; 29-sep-2015).

Good functional recovery of complex elbow dislocations treated with hinged external fixation: a multicenter prospective study

BACKGROUND

After a complex dislocation, some elbows remain unstable after closed reduction or fracture treatment. Function after treatment with a hinged external fixator theoretically allows collateral ligaments to heal without surgical reconstruction. However, there is a lack of prospective studies that assess functional outcome, pain, and ROM.

QUESTIONS/PURPOSES

We asked: (1) In complex elbow fracture-dislocations, does treatment with a hinged external fixator result in reduction of disability and pain, and in improvement in ROM, function, and quality of life? (2) Does delayed treatment (7 days or later) have a negative effect on ROM after 1 year? (3) What are the complications seen after external fixator treatment?

METHODS

During a 2-year period, 11 centers recruited 27 patients 18 years or older who were included and evaluated at 2 and 6 weeks and at 3, 6, and 12 months after surgery as part of this prospective case series. During the study period, the participating centers agreed on general indications for use of the hinged external fixator, which included persistent instability after closed reduction alone or closed reduction combined with surgical treatment of associated fracture(s), when indicated. Functional outcome was evaluated using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH; primary outcome) score, the Mayo Elbow Performance Index (MEPI), the Oxford Elbow Score, and the level of pain (VAS). ROM, adverse events, secondary interventions, and radiographs also were evaluated. A total of 26 of the 27 patients (96%) were available for followup at 1 year.

RESULTS

All functional and pain scores improved. The median QuickDASH score decreased from 30 (25(th)-75(th) percentiles [P25-P75], 23-40) at 6 weeks to 7 (P25-P75, 2-12) at 1 year with a median difference of -25 (p < 0.001). The median MEPI score increased from 80 (P25-P75, 64-85) at 6 weeks to 100 (P25-P75, 85-100) at 1 year with a median difference of 15 (p < 0.001). The median Oxford Elbow Score increased from 60 (P25-P75, 44-68) at 6 weeks to 90 (P25-P75, 73-96) at 1 year with a median difference of 29 (p < 0.001). The median VAS decreased from 2.8 (P25-P75, 1.0-5.0) at 2 weeks to 0.5 (P25-P75, 0.0-1.9) at 1 year with a median difference of -2.1 (p = 0.001). ROM also improved. The median flexion-extension arc improved from 50° (P25-P75, 33°-80°) at 2 weeks to 118° (P25-P75, 105°-138°) at 1 year with a median difference of 63° (p < 0.001). Similarly, the median pronation-supination arc improved from 90° (P25-P75, 63°-124°) to 160° (P25-P75, 138°-170°) with a median difference of 75° (p < 0.001). At 1 year, the median residual deficit compared with the uninjured side was 30° (P25-P75, 5°-35°) for the flexion-extension arc, and 3° (P25-P75, 0°-25°) for the pronation-supination arc. Ten patients (37%) experienced a fixator-related complication, and seven patients required secondary surgery (26%). One patient reported recurrent instability.

CONCLUSIONS

A hinged external elbow fixator provides enough stability to start early mobilization after an acute complex elbow dislocation and residual instability. This was reflected in good functional outcome scores and only slight disability despite a relatively high complication rate.

Treatment of unstable elbow dislocations with hinged elbow fixation-subjective and objective results

BACKGROUND

The aim of this study was to provide subjective and objective results of surgical treatment of unstable elbow dislocations with the hinged external fixation technique.

METHODS

Twenty-six patients were available for re-examination after treatment. Parameters used to quantify the subjective functional results were the Mayo Elbow Performance Score, the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire, and the stability of the elbow joint. In addition, we measured the medial and lateral joint space by varus and valgus stress ultrasound examinations of the elbow.

RESULTS

The mean Mayo Elbow Performance Score was 93.5 (±8.3 standard deviation), and the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire showed an average of 7.3 points (±8.9 standard deviation). We saw 18 patients with stable joints and 8 patients with slight instability. In the ultrasound stress test, we saw a significant difference of the affected joint under varus stress (7.8 ± 1.7 mm) compared with the healthy joint (5.8 ± 1.2 mm) laterally. Furthermore, medially the gap was significantly larger (4.8 ± 0.9 mm; treated elbow) than contralaterally under valgus stress (3.3 ± 0.7 mm) (P < .001).

CONCLUSION

Closed reduction and hinged external fixation of unstable elbow dislocations resulted in good and very good results. We could identify a slight difference in the stability of the affected elbow compared with the contralateral side in all patients without clinical relevance.

Surgical accuracy in identifying the elbow rotation axis on fluoroscopic images

PURPOSE

To assess the accuracy of surgeons in identifying elbow rotation axis (RA) on fluoroscopic images and to measure the interobserver variability.

METHODS

Five healthy subjects underwent 3-dimensional computed tomography (CT) analysis of their nondominant elbow. Real-time rotation software enabled surgeons to approximate the elbow RA on CT-reconstructed fluoroscopy, which was repeated twice with different starting positions to increase the number of observations. The surgeons used anatomical landmarks of choice. Analysis of variance (ANOVA) was used to determine structural error differences between surgeons, and intraclass correlation coefficients (ICCs) were used to determine the corresponding interobserver variability.

RESULTS

Eight subspecialty-trained trauma surgeons (P.K., N.W.L.S., V.M.d.J., P.J., G.M.K., R.W.P., T.S., B.A.v.D.) participated and attempted to identify the RA on reconstructed fluoroscopy. A total of 15 RA definitions on 5 elbows were recorded per surgeon. The surgeons had a mean rotational error of 5° (range, < 1°-13°) and mean translational error of 1 mm (range, < 1-8 mm), compared with the true elbow RA as measured by the 3-dimensional CT analysis. The ANOVA showed structural differences between surgeons in rotational and translational errors, indicating that some surgeons consistently had more accurately identified the elbow RA than others. The ICC was 0.12 for rotational error and 0.10 for translational error, indicating a large interobserver variability.

CONCLUSIONS

We show in this in vivo study that identification of the elbow RA on fluoroscopy is associated with substantial rotational errors and large inconsistencies among surgeons. Implementation of standardized anatomical landmarks is required to improve surgeons' accuracy. These landmarks should preferably take into account both the coronal and the sagittal planes, using the orientation of the capitellum and trochlea as well as the posterior distal humeral cortex.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Course of the radial nerve in relation to the center of rotation of the elbow--the need for a rational safe zone for lateral pin placement

PURPOSE

To investigate the course and variability of the radial nerve along the lateral humerus in relation to the center of rotation of the elbow joint in the context of lateral pin placement for hinged external fixation.

METHODS

A total of 95 formalin-fixed upper extremities were dissected. The course of the radial nerve along the lateral aspect of the humerus was measured at 3 landmarks with respect to the center of rotation of the elbow. We analyzed the data and the landmark positions correlated with the length of the humerus.

RESULTS

The measured positions of 3 landmarks of the radial nerve in the lateral aspect of the humerus ranged from 19% to 43% of the length of the humerus and were located, on average, 6.0, 9.7, and 13.5 cm from the lateral center of rotation.

CONCLUSIONS

These data help predict the humeral course of the radial nerve and define a safe zone for pin implantation. However, because of variability in the course of the radial nerve, a safe zone cannot fully ensure prevention of iatrogenic injury to the nerve. The safest method of pin application remains mini-open dissection and visual implantation.

CLINICAL RELEVANCE

Based on this cadaveric study, it is not possible to define a rational safe zone. The safest method of pin application for dynamic external fixation of the elbow is to perform a mini-open dissection with direct visualization.

Elbow dislocations: a review ranging from soft tissue injuries to complex elbow fracture dislocations

This review on elbow dislocations describes ligament and bone injuries as well as the typical injury mechanisms and the main classifications of elbow dislocations. Current treatment concepts of simple, that is, stable, or complex unstable elbow dislocations are outlined by means of case reports. Special emphasis is put on injuries to the medial ulnar collateral ligament (MUCL) and on posttraumatic elbow stiffness.

Midterm Results of 58 Fractures of the Coronoid Process of the Ulna and their Concomitant Injuries

BACKGROUND

In general, fractures of the coronoid process are rare and usually occur in combination with additional elbow joint injuries. The treatment of these injuries aims to regain a stable as well as a flexible and loadable joint. Although there is currently little evidence, therapy recommendations remain controversial. Therefore, the aim of this study was to prognostically determine relevant factors for therapy recommendation by analysing a representative patient population of two trans-regional trauma centres.

MATERIAL AND METHODS

Seventy-seven patients with a fracture of the coronoid process were treated within an 8-year period (2001 to 2009). After an average of 48 months (SD 31), treatment outcome of 58 patients (75%) was acquired. The results were statistically analysed.

RESULTS

The average age of the patient was 51.8 years (SD 13.6); 36 were male and 34 had a fracture on the right arm. Applying the fracture types of the coronoid process in accordance with Regan/Morrey, the result was: Type I (19), II (17) and III (22). Further injuries were also detected: 40 radial head fractures, 17 proximal ulnar fractures and 2 fractures of the olecranon. A luxation was detected in 44 of the 58 patients (76%). The patients' average MEPS (Mayo Elbow Performance Score) was 80.6 points (SD 18), with significant differences between the various therapy strategies. Fifteen% of the coronoid process fractures were reconstructable to a limited extent only by means of osteosynthesis. In 33% of the patients, instabilities remained. The average extension/flexion came to 107° (SD 28), and pronation and supination 153° (SD 38).

CONCLUSION

At present, a surgical therapy of ligamentary injuries cannot be statistically justified. A stable osseous reconstruction appears to make more sense. The strongest negative prognostic parameters in our patient population were: therapy with an external fixator, immobilisation for more than 21 days, the occurrence of complications and unstable osteosyntheses on the coronoid process.

Hinged external fixator placement at the elbow: navigated versus conventional technique

INTRODUCTION

During the application of a hinged external elbow fixator, exact placement of the central pin remains difficult. Proper placement often necessitates multiple drilling attempts and fluoroscopic localization, which can be time consuming. We hypothesized that use of computerized navigation would enable a more precise placement of the central axis pin and would reduce the total number of drilling attempts.

MATERIALS AND METHODS

Twelve elbow models incorporating soft tissue coverage were used in this study. First, the optimal placement trajectory (OPJ) of the axis pin was defined in the anterior-posterior (AP) and lateral planes of the elbow. Six elbows were used with the navigation system and the axis pin was inserted in combination with a conventional fluoroscopy system under constant two-dimensional guidance from the virtual images. The pins for the remaining six elbow specimens were implanted conventionally under fluoroscopic guidance. The distances and angular deviations from the OPJ position were measured, and the results for the conventional placement and computer navigation groups were compared. To determine the definitive axis pin placement, a CT scan of each elbow with 1-mm slice thickness was used and the results were measured based on the defined optimal pin placement. AP plane angulations and lateral plane distances were calculated in relation to the optimal insertion trajectory for each specimen. Finally, we counted the overall number of drilling attempts needed to find the optimal position for the axis pin.

RESULTS

For the AP angulations, of the six elbows implanted using the conventional technique, half (n=3) had deviations of ≥20° from the optimal axis. In contrast, in the navigated group, all cases (n=6) were within 20° of the optimal axis in the AP plane. The mean AP angulation deviation in the conventional group was 20.5°, compared to 15° in the navigation group (p=0.077). For the lateral distances, the mean distance from the drilling point to the point of optimal placement was 3.83 mm in the conventional group, versus 1.83 mm in the navigation group (p=0.042). For all navigated cases, only one drilling attempt was necessary to achieve the desired position of the axial pin.

CONCLUSION

Compared with the conventional method of axis pin placement for an elbow fixator, two-dimensional navigation allows a reduction in the number of drilling attempts required. Furthermore, the accuracy in terms of AP angulation and lateral distance from a defined optimal placement is better when compared to that obtained with the conventional technique.

Complex elbow dislocation associated with radial and ulnar diaphyseal fractures: a rare combination

We illustrate a rare complex dislocation of the elbow involving a posterior ulno-humeral dislocation associated with open diaphyseal fracture of the ulna, radial shaft fracture, Type 1 coronoid fracture and neuropraxia of the deep branch of the radial nerve. The isolated ulno-humeral dislocation without radio-capitellar involvement, and ulnar diaphyseal fracture, makes this "reverse Monteggia" type of injury pattern very unique. This patient was managed with an initial reduction of his ulno-humeral joint and stabilization of his radius and ulna fractures. He underwent a delayed medial collateral ligament reconstruction a few days later. His fractures went on to unite fully, his elbow joint remained stable, and he achieved good range of motion of his elbow.