Michael Hackl

The treatment of simple elbow dislocation in adults.

BACKGROUND Simple elbow dislocation is a complex soft-tissue injury that can cause permanent symptoms. Its incidence is 5 to 6 cases per 100 000 persons per year. Its proper treatment is debated; options range from immobilization in a cast to surgical intervention. METHODS We systematically reviewed the literature on the treatment of simple elbow dislocation and performed a meta-analysis, primarily on the basis of clinical scores and secondarily with respect to pain, range of motion, and return to work. RESULTS A randomized controlled trial (RCT) showed that clinical results at short-term follow-up were superior for early functional treatment compared to immobilization in a cast. Brief immobilization, however, reduced pain initially, and the long-term results of early mobilization and immobilization in a cast were the same. Our meta-analysis showed that early mobilization enables patients to return to work earlier (difference of mean values -2.91, 95% confidence interval [CI] -3.18 to -2.64), and that the extent of soft-tissue injury is correlated with the clinical outcome (inverse relationship; difference of mean values -12.07, 95% CI -23.88 to -0.26). Surgical and conservative treatment were compared in a single RCT, which revealed no significant difference in outcomes. A meta-analysis of two retrospective comparative studies showed no advantage of immediate ligament repair over delayed surgery. CONCLUSION Early functional treatment is the evidence-based therapeutic standard for simple elbow dislocation. The past few years have seen further developments in surgery for simple elbow dislocation. Further study is needed to determine whether surgery for elbow dislocation with high-grade instability can prevent persistent pain, limitation of motion, and chronic instability.

Reliability of Magnetic Resonance Imaging Signs of Posterolateral Rotatory Instability of the Elbow

PURPOSE To evaluate radiographic signs of posterolateral rotatory instability (PLRI) on magnetic resonance imaging (MRI). The goal was to establish objective radiographic criteria to aid in the diagnosis of PLRI. METHODS The MRI scans of 60 patients were evaluated retrospectively. Two study groups were compared. Group 1 (n = 30) consisted of unstable elbows in which PLRI was confirmed by clinical examination and arthroscopy. Group 2 (stable; n = 30) served as the control group. Patients in group 2 had transient epicondylitis without clinical suspicion of instability. Joint incongruity was analyzed for sagittal views through the radial head and the coronoid tip and for coronal and axial views. Interobserver and intra-observer reliability were evaluated. RESULTS In the sagittal view through the radial head, average radiocapitellar incongruity differed significantly between groups 1 and 2. In addition, mean ulnohumeral incongruity in an axial view through the motion axis of the distal humerus showed significant differences between groups. Sagittal views through the tip of the coronoid and coronal views did not reveal significant differences in patients with unstable elbows compared with the control group. CONCLUSIONS The current study provides useful MRI criteria indicative of PLRI when combined with physical examination. Cutoff points of 1.2 mm for radiocapitellar incongruity (sagittal view) and 0.7 mm for axial ulnohumeral incongruity (axial view) are suitable to screen for PLRI. Radiocapitellar incongruity greater than 2 mm and axial ulnohumeral incongruity greater than 1 mm are highly suspicious of elbow instability. TYPE OF STUDY/LEVEL OF EVIDENCE Diagnostic IV.

The course of the posterior interosseous nerve in relation to the proximal radius: Is there a reliable landmark?

PURPOSE The posterior interosseous nerve (PIN) is closely related to the proximal radius, and it is at risk when approaching the proximal forearm from the ventral and lateral side. This anatomic study analyzes the location of the PIN in relation to the proximal radius depending on forearm rotation by means of a novel investigation design. The purpose of this study is to define landmarks to locate the PIN intraoperatively in order to avoid neurological complications. METHODS We dissected six upper extremities of fresh-frozen cadaveric specimens. The mean donor age at the time of death was 81.2 years. The PIN was dissected and marked on its course along the proximal forearm with a 0.3-mm flexible radiopaque thread. Three-dimensional (3D) X-ray scans were performed, and the location of the nerve was analyzed in neutral rotation, supination, and pronation. RESULTS In the coronal view, the PIN crosses the radial neck/shaft at a mean of 33.4 (±5.9)mm below the radial head surface (RHS) in pronation and 16.9 (±5.0)mm in supination. It crosses 4.9 (±2.2)mm distal of the most prominent point of the radial tuberosity (RT) in pronation and 9.6 (±5.2)mm proximal in supination. In the sagittal view, the PIN crosses the proximal radius 61.8 (±2.9)mm below the RHS in pronation and 41.1 (±3.6)mm in supination. The nerve crosses 29.2 (±6.2)mm distal of the RT in pronation and 11.0 (±2.8)mm in supination. CONCLUSION With this novel design, the RT could be defined as a useful landmark for intraoperative orientation. On a ventral approach, the PIN courses 10mm proximal of it in supination and 5mm distal of it in pronation. Laterally, pronation increases the distance of the PIN to the RT to approximately 3cm.

Elbow Positioning and Joint Insufflation Substantially Influence Median and Radial Nerve Locations.

BackgroundThe median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations.Questions/purposesIn a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens.MethodsThe median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90° flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens.ResultsThe mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% ± 17% in extension to 91% ± 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%–41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, −13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 ± 1.3 mm in extension, 9.1 ± 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04–5.36 mm; p < 0.001), and 12.6 ± 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81–6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 ± 1.8 mm in extension to 7.7 ± 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96–5.04 mm; p = 0.005) and to 11.9 ± 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66–6.74 mm; p = 0.002).ConclusionsThe radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90° flexion and triples after joint insufflation.Clinical RelevanceElbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure.

From radial head to radiocapitellar to total elbow replacement: A case report

Highlights • Overstuffing is a serious yet avoidable complication of radial head arthroplasty.• Overstuffing severely alters elbow joint kinematics and leads to capitellar erosion.• Radiocapitellar arthroplasty can be a salvage procedure in such cases.• Limited clinical data is available thus far regarding radiocapitellar arthroplasty.• The possibility for early failure due to ulnohumeral erosion has to be considered.

Nonoperative management of blunt hepatic trauma: A systematic review.

BACKGROUND Nonoperative management (NOM) has become the standard treatment in hemodynamically stable patients with blunt hepatic injuries. While the reported overall success rates of NOM are excellent, there is a lack of consensus regarding the risk factors predicting the failure of NOM. The aim of this systematic review was to identify the incidence and prognostic factors for failure of NOM in adult patients with blunt hepatic trauma. METHODS Prospective studies reporting prognostic factors for the failure of nonoperative treatment of blunt liver injuries were identified by searching MEDLINE and the Cochrane Central Register of Controlled Trials. RESULTS We screened 798 titles and abstracts, of which 8 single-center prospective observational studies, reporting 410 patients, were included in the qualitative and quantitative synthesis. No randomized controlled trials were found. The pooled failure rate of NOM was 9.5% (0–24%). Twenty-six prognostic factors predicting the failure of NOM were reported, of which six reached statistical significance in one or more studies: blood pressure (p < 0.05), fluid resuscitation (p = 0.02), blood transfusion (p = 0.003), peritoneal signs (p < 0.0001), Injury Severity Score (ISS) (p = 0.03), and associated intra-abdominal injuries (p < 0.01). CONCLUSION There is evidence that patients presenting with clinical signs of shock, a high ISS, associated intra-abdominal injuries, and peritoneal signs are at an increased risk of failure of NOM for the treatment of blunt hepatic injuries. LEVEL OF EVIDENCE Systematic review, level III.

The circumferential graft technique for treatment of multidirectional elbow instability: a comparative biomechanical evaluation.

BACKGROUND Ligament reconstruction with a circumferential graft represents an innovative technique for treatment of multidirectional elbow instability. This biomechanical study compared the stability of the intact elbow joint with the circumferential graft technique and the conventional technique. METHODS Seven fresh frozen cadaveric elbows were evaluated for stability against valgus and varus/posterolateral rotatory forces (3 Nm) over the full range of motion. Primary stability was determined for intact specimens, after sectioning of the collateral ligaments, after applying the circumferential graft technique (box-loop), and after conventional collateral ligament reconstruction. Cyclic loading (1000 cycles) was performed to assess joint stability and stiffness of the native ligaments and the tendon grafts. RESULTS Primary stability of both reconstruction techniques was equal to the native specimens (P = .17-.91). Sectioning of the collateral ligaments significantly increased joint instability (P < .001). The reconstruction techniques provided equal stability after 1000 cycles (P = .78). Both were inferior to the intact specimens (P = .02). Cyclic loading caused a significantly lower increase in stiffness of the native ligaments compared with the tendon grafts of either reconstruction technique (P = .001-.008). Significantly better graft stiffness was retained with the circumferential graft technique compared with conventional reconstruction (P = .04). CONCLUSION Neither reconstruction technique fully reproduces the biomechanical profile of the native collateral ligaments. The circumferential graft technique seems to resist cyclic loading slightly better than the conventional reconstruction technique, yet both reconstruction techniques provide comparable stability.

Peri-implant failure in dual plating of the distal humerus—A biomechanical analysis with regard to screw and plate positioning

PURPOSE The aim of this biomechanical study was to analyse the influence of plate and screw positioning on peri-implant failure in dual plate osteosynthesis. We hypothesized that screw positioning rather than plate configuration influences the risk of peri-implant fractures. METHODS Twenty macerated humerus specimens were available. 5 groups of 4 were built according to specimen size. Locking dual plates (Medartis, Switzerland) were randomly applied to the distal humerus of the specimens in 4 types of configuration: Bending forces were applied using a universal testing machine until peri-implant fracture occurred. RESULTS Mean failure loads for respective configuration types were as follows: P1: 428.7 (±84.2) N, A1: 410.0 (±54.7) N, A0: 297.8 (±48.3) N, P0: 261.0 (±65.0) N. Configurations with positioning of the most proximal screws at different levels (P1, A1) reached significantly higher failure loads when compared to screw placement at the same level (P0, A0) (0.01≤p≤0.03). Altering the plate configuration did not significantly influence failure loads (0.34≤p≤0.58). CONCLUSIONS The results of this study suggest that placement of the most proximal screws rather than the configuration of the plates is critical regarding the predetermined risk of peri-implant failure in dual plate osteosynthesis of the distal humerus. Varying levels of the outermost screws of corresponding double plates seem to be crucial to avoid complications related to the osteosynthesis.

Rare implant-specific complications of the MoPyC radial head prosthesis

BACKGROUND According to currently available data, the clinical short-term results of the MoPyC radial head prosthesis (Bioprofile, Tornier, Montbonnot-Saint-Martin, France) seem favorable. However, we have encountered several implant-specific complications in recent years. Hence, this case series reports rare complications after radial head arthroplasty with the MoPyC prosthesis to make surgeons aware of their existence and to provide information about the underlying cause and possible salvage strategies. METHODS A retrospective chart review from 2011 to 2016 was conducted to identify all adult patients with a minimum 2-year follow-up who underwent or were referred after radial head arthroplasty with the MoPyC radial head prosthesis and experienced implant-related complications. RESULTS Five patients with 7 implant-related complications were found. One patient experienced breakage of the pyrocarbon head. In another patient, breakage of the stem and-after revision surgery-partial breakage were observed. Disassembly of the prosthesis was seen in 1 case. Extensive periprosthetic stress shielding was seen in 3 patients resulting in symptomatic loosening (1), periprosthetic radial neck fracture (1), and stem migration (1). CONCLUSIONS Whereas clinical short-term results of the MoPyC radial head prosthesis are satisfactory, rare implant-related complications can occur. Surgeons should be aware of these complications as they may lead to a poor outcome.

Suture button reconstruction of the central band of the interosseous membrane in Essex-Lopresti lesions: a comparative biomechanical investigation

Surgical reconstruction of the interosseous membrane may restore longitudinal forearm stability in Essex-Lopresti lesions. This study aimed to compare the longitudinal stability of the intact forearm with a single-bundle and a double-bundle reconstruction of the central band of the interosseous membrane using digital image correlation with a three-dimensional camera system. Single and cyclic axial loading of eight fresh-frozen forearm specimens was carried out in the intact state, after creation of an Essex-Lopresti lesion, after a single-bundle and after a double-bundle reconstruction of the central band using a TightRope® (Arthrex GmbH, Munich, Germany) construct. Instability significantly increased after creation of an Essex-Lopresti lesion. The stability of intact specimens was similar to both reconstruction techniques. The results of this study suggest that TightRope® reconstruction of the central band restores longitudinal forearm stability. However, the single-bundle technique may be less reliable than double-bundle reconstruction. Level of evidence: Basic Science Study