Intraoperative visualization of the posterolateral ulnohumeral joint space is reliable to indicate overlengthening in radial head arthroplasty.

INTRODUCTION: Avoiding overlengthening in radial head arthroplasty (RHA) is essential for the prognosis of the elbow joint. An overlengthening from 2 mm is visible due to widening of the anterolateral ulnohumeral joint space but intraoperatively, this particular joint space is difficult to visualize. The commonly used Kocher approach allows visualization of the posterolateral joint space without additional instruments or further surgical release of the already unstable elbow. The aim of our study was to investigate whether the visualization of the posterolateral joint space is also a reliable method to indicate overlengthening in RHA. MATERIAL AND METHODS: RHA was performed in five human cadaveric specimens with the forearm, wrist, and hand intact. The lateral ligament complex was detached and an anatomic transosseous refixation was performed. Six stages of implantation heights were documented: native joint (1), RHA at the anatomic height (2), + 2 mm (3), + 4 mm (4), + 6 mm (5) and - 2 mm (6). Macroscopic measurement and digital image analysis of the posterolateral and anterolateral ulnohumeral joint spaces were performed. RESULTS: All stages of overlengthening showed a significant increase in posterolateral and anterolateral joint space widening (p < 0.05). The posterior and anterior joint space showed excellent intraclass correlation. CONCLUSION: Visualization of the posterolateral aspect of the ulnohumeral joint space is a reliable indicator for overlengthening in RHA without further compromising an already unstable elbow. Correlation to the findings of the anterolateral ulnohumeral joint space in different implants leads to the assumption that visualization of either the anterior or posterior ulnohumeral joint space is universally applicable to determine overlengthening in RHA, regardless of the type of the radial head implant.

Plate Osteosynthesis of Proximal Ulna Fractures-A Biomechanical Micromotion Analysis.

PURPOSE: Double plating has been promoted, in recent years, as an alternative treatment method for proximal ulna fractures. This study aimed to compare the biomechanical properties of double-plate osteosynthesis with posterior plate fixation using a novel investigational design utilizing a 3-dimensional camera system to analyze fracture micromotion. METHODS: Fourteen fresh-frozen specimens were available for this study. Mayo type IIA fractures of the olecranon were created and internal fixation was performed with either an angular stable posterior plate or angular stable double plates. Fracture micromotion was evaluated by means of digital image correlation with a 3-dimensional camera system before and after dynamic cyclic loading from 15° to 90° of elbow flexion with a pulling force of 25 N to 80 N. RESULTS: Micromotion of fragments was less pronounced in double-plate osteosynthesis when compared with single plates before and after cyclic loading. However, overall results were similar. Two of the single plates failed during cyclic loading but there were no failures in the double plates. CONCLUSIONS: This biomechanical analysis shows that single and double plating results in comparable stability of fixation. Although the double-plating technique tends to provide more stable fixation, relevant differences were not observed. CLINICAL RELEVANCE: Double plating potentially represents an efficient option for fixation of proximal ulna fractures. It could decrease the risk of soft tissue complications owing to their low profile and the superior soft tissue coverage.

The influence of three-dimensional planning on decision-making in total shoulder arthroplasty.

BACKGROUND: Long-term results and complication rates in shoulder arthroplasty are related to implant positioning. Current literature reports increased precision in glenoid component positioning using 3-dimensional (3D) computed tomography (CT) planning tools. This study evaluated the accuracy of glenoid version and inclination measurements using 2D CT scans compared with a validated 3D software program and its influence on decision making on implant selection. METHODS: Preoperative CT scans were obtained from 50 patients undergoing total shoulder arthroplasty. Glenoid version and inclination measurements were performed in random order by 3 independent qualified orthopedic surgeons on reformatted 2D CT scans. Indication for anatomic or reverse shoulder arthroplasty was based on glenoid deformity and on rotator cuff conditions. Results were compared with those from a validated 3D computer software program, and the final decision was made according to the 3D planning. RESULTS: Mean preoperative glenoid retroversion on reformatted 2D CT scans was 11.9° ± 9.6° and mean superior inclination was 10.7° ± 8.6°. When the 3D software was used, glenoid retroversion averaged 15.1° ± 10.6° and superior inclination averaged 8.9° ± 9.9°. The 2D CT demonstrated good interobserver and intraobserver reliability for glenoid version and inclination. Decision on the choice of implant was adjusted in 7 patients after the 3D planning. CONCLUSIONS: Our findings show that measurements of glenoid version and inclination on reformatted 2D CT scans are less accurate compared with 3D measurements. A preoperative 3D planning software allows for improvement of virtual glenoid positioning and influences the decision making process.

Long-term analysis of revision reverse shoulder arthroplasty using cemented long stems.

BACKGROUND: Revision of failed shoulder arthroplasty is often associated with poor results and a high rate of complications. Significant humeral bone loss after removal of long stems poses a considerable surgical challenge. Therefore, the aim of our study was the evaluation of the clinical and radiologic outcome of cemented long-stem humeral components in revision reverse shoulder arthroplasty with a minimum 5 years' follow-up. METHODS: Between June 2001 and June 2009, revision reverse shoulder arthroplasty using long-stem cemented humeral components was performed in 124 patients. Mean age at time of surgery was 69.6 years (range, 42-87 years). Complete clinical and radiographic data were available in 50 patients at a mean of 7 years (range, 5-11.6 years). Postoperative radiographs were evaluated for radiolucent lines, implant migration, fracture, and glenoid notching. RESULTS: The mean Constant score improved from 11.1 points (range, 0-27 points) to 39.5 points (range, 14-73 points) at the latest follow-up. Progressive humeral radiolucency was present in 24 patients, including 6 patients demonstrating complete loosening or progressive distal migration of the humeral stem. We noted an overall of 12 additional complications in 8 patients, necessitating revision surgery in 16. CONCLUSION: The use of long-stem humeral components is a beneficial treatment in revision reverse shoulder arthroplasty. Nevertheless, the high percentage of patients with humeral loosening is concerning. Modular cementless revision stems that are adapted to the distal humeral medullary canal and additional distal screw and cable fixation might enhance durable distal fixation in case of advanced bone loss.

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.

Shoulder arthroplasty in Germany: 2005-2012.

INTRODUCTION: The field of shoulder endoprothetics has undergone a rapid development in the last years. The purpose of the study was to provide an overview of the development of shoulder arthroplasties in Germany from 2005 until 2012. This study hypothesized that the surgical procedures of the shoulder joint is still increasing and have not reached a plateau until 2012. METHODS: Data of the German federal statistical office from 2005 until 2012 were analyzed to quantify hemiarthroplasty, anatomic total shoulder and reversed total shoulder arthroplasty rates depending on age, gender and main coded indications. Procedure codes and diagnosis were analyzed for each year. Comparative analyses were used to visualize the difference between the types of shoulder endoprostheses. RESULTS: A total number of 139.272 shoulder arthroplasties were performed between 2005 and 2012. Total should arthroplasties have increased continuously until 2009. In 2009 more total shoulder arthroplasties have been performed than hemiprothesis implantations, which have culminated in 2008. All in all, women have been treated 3-fold higher than men regarding hemiarthroplasty, total shoulder arthroplasties or reversed total shoulder arthroplasties. Under the age of 60 years the majority of treated patients were male. CONCLUSION: Since 2005 shoulder arthroplasties are still increasing in Germany, whereas a slight reduction could be detected for shoulder hemiarthroplasty from 2009 up until 2012. Meanwhile total shoulder arthroplasties and reversed total shoulder arthroplasties are still increasing. Women have experienced a 3-fold higher hemiarthroplasty, total shoulder and reversed shoulder arthroplasties than men except for individual younger than 60 years.

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

BACKGROUND: The 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/PURPOSES: In 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. METHODS: The 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. RESULTS: The 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). CONCLUSIONS: The 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 RELEVANCE: Elbow 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.

Anatomic relations between the lateral collateral ligament and the radial head: implications for arthroscopic resection of the synovial fold of the elbow.

PURPOSE: The purpose of this study was to determine the anatomic relationship between the radial head and the lateral collateral ligament (LCL) and when the LCL would be at risk of iatrogenic injury during arthroscopic resection of the synovial fold. METHODS: Thirty-four formalin-fixed upper extremities were dissected. A projection of the LCL onto the radial head was marked with a needle. The percentage of the posterior border of the radial head overlaid by the LCL was digitally measured. A portion of the projection of the LCL was statistically correlated with the overall diameter of the radial head. RESULTS: The overall diameter of the radial head was 21.2 mm ± 2.3. The proportionate projection of the medial border of the LCL onto the radial head was 5.3 ± 1.6 mm on average. The lateral 25 % of the radial head was overlaid by the LCL with a maximum value of 40 % on average. The inter- and intraobserver reliability showed very good accordance with the digital measurements (r > 0.8). CONCLUSION: Care must be taken when performing a resection in the lateral 40 % of the radial head, whereas resection in the medial 60 % of the radial head appears to be safe. The LCL is an important stabiliser of the elbow joint, a lesion of which by undeliberate arthroscopic dissection may lead to joint instability. Iatrogenic injury to the LCL presumably can be prevented when respecting the given data. LEVEL OF EVIDENCE: Experimental study.

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.

Is an extension of the safe zone possible without jeopardizing the proximal radioulnar joint when performing a radial head plate osteosynthesis?

BACKGROUND: Proximal radial fractures are common elbow injuries. Because of the fracture pattern, stability criteria, or plate configuration, a plate position outside the "safe zone" (SZ) may be required in some cases when performing a radial head plate osteosynthesis. We examined the gross anatomy of the radial head and analyzed different so-called low-profile and precontoured radial head and neck plates with respect to the SZ. MATERIALS AND METHODS: Macroscopic measurements of the radial head and neck of 22 formalin-fixed human cadaveric upper extremities were obtained. The SZ was determined by maximum forearm rotation. If the edge of a plate could be extended beyond the respective SZ boundary without jeopardizing the proximal radioulnar joint (PRUJ) in maximum forearm rotation, a new plate-specific SZ boundary was set. RESULTS: The mean SZ was 133° (SD, 14°). Among the 5 plates studied, only the 2 radial neck designs allowed the anterior edge of the plate to partially pass the lesser sigmoid notch of the ulna and consequently afforded a significant extension of the SZ in maximum pronation. All 3 radial head designs had to remain within the SZ to avoid interference with the PRUJ. A safe plate position depends on individual plate dimensions, particularly the proximal plate width, and the diameter of the radial head. The smaller the head diameter, the more accurately a plate must be placed within the SZ. CONCLUSIONS: If an extension of the SZ in radial head plate osteosynthesis is not essential, we recommend respecting the SZ to minimize the possibility of interference with the PRUJ.

The course of the median and radial nerve across the elbow: an anatomic study.

INTRODUCTION: Nerve transection has been described as complication of arthroscopic elbow arthrolysis. Therefore, the goal of this study was to define bony landmarks for intraoperative orientation regarding the location of the median and radial nerve. METHODS: In 22 formalin-fixated upper extremities, the radial and median nerves were dissected and marked with respect to their native course. A 3D X-ray scan was performed. The distances of the radial nerve to the radial head (R1), the capitulum (R2), and its lateral border (RC) were measured. The location of the radial nerve in relation to the transversal diameter of the humeral condyle (HC) was calculated. Similarly, the distances of the median nerve to the trochlea (M1), the medial border of the trochlea (M2), and its relation to HC were calculated. RESULTS: The mean value for R1 was 8 mm (±2.9 mm), for R2 was 11.3 mm (±3.8 mm), and for RC was 10.6 mm (±5.1 mm). RC/HC averaged 24 % (±11 %). M1 averaged 11.7 mm (±5.2 mm), and M2 was 2.4 mm (±4.1 mm). M2/HC averaged 6 % (±9 %). CONCLUSIONS: The radial nerve is located ventral to the central third of the capitulum. The median nerve lies ventral to the medial quarter of the humeral condyle. When performing arthroscopic arthrolysis, this information should be kept in mind during anterior capsulectomy.

Do the radial head prosthesis components fit with the anatomical structures of the proximal radioulnar joint?

PURPOSE: The fitting accuracy of radial head components has been investigated in the capitulo-radial joint, and reduced contact after prosthetic replacement of the radial head has been observed. The kinematics of the proximal radioulnar joint (PRUJ) are affected by radial head arthroplasty as well, but have not yet been investigated in this regard. METHODS: The elbow joints of 60 upper extremities of formalin-fixed body donors were disarticulated to obtain a good view of the PRUJ. Each specimen was mounted on the examining table and radial head position in the native PRUJ was assessed in neutral position, full pronation, and full supination. Measurements were repeated after implantation of mono- and bi-polar prostheses. RESULTS: Analysis of the distribution of the joint contacts in the compartments showed significant differences after radial head replacement. In comparison to the native joint, after bipolar and monopolar radial head replacement, the physiological shift of the proximal radius was altered. DISCUSSION: The physiological shift of the joint contact of the radial head from anterior to posterior during forearm rotation that was found in the native joint in our cadaver model was not observed after prosthetic replacement. With higher conformity and physiological kinematic of radial head prostheses, possibly lower shear forces and lower contact pressures would be generated. CLINICAL RELEVANCE: The tested radial head prostheses do not replicate the physiological kinematics of the radial head. Further development in the prosthesis design has to be made. The meticulous reconstruction of the annular ligament seems to be of importance to increase joint contact.

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.

Tension band wiring in olecranon fractures: the myth of technical simplicity and osteosynthetical perfection.

PURPOSE: The tension band wiring (TBW) technique is a common treatment for the fixation of olecranon fractures with up to three fragments. The literature and surgeons describe TBW as an uncomplicated, always available and convenient operation producing excellent results. The purpose of this study was to determine whether TBW is more ambitious than believed or the procedure provides an increased level of tolerance concerning the surgical technique. METHODS: This study reviewed 239 TBW cases in patients with olecranon fractures or osteotomies. We reviewed a total of 2,252 X-rays for ten operative imperfections: (1) nonparallel K-wires, (2) long K-wires, (3) K-wires extending radially outwards, (4) insufficient fixation of the proximal ends of the K-wires, (5) intramedullary K-wires, (6) perforation of the joint surface, (7) single wire knot, (8) jutting wire knot(s), (9) loose figure-of-eight configuration, and (10) incorrect repositioning. RESULTS: On average, there were 4.24 imperfections per intervention in the cases reviewed. A total of 1,014 of 2,390 possible imperfections were detected. The most frequent imperfections were insufficient fixation of the proximal ends of the K-wires (91% of all cases), the use of a single wire knot (78%) and nonparallel K-wires (72%). Mayo IIa (n = 188) was the most common fracture type. CONCLUSIONS: Our results and the number of complications described by the literature together support the conclusion that TBW is not as easy as surgeons and the literature suggest. Although bone healing and the functional results of TBW are excellent in most cases, the challenges associated with this operation are underestimated. LEVEL OF EVIDENCE: IV, treatment study.

Anatomical fit of seven different palmar distal radius plates.

INTRODUCTION: The purpose of this study was to compare the anatomical fit of different, precontoured palmar distal radius plates. METHODS: The anatomical fit of seven different types of palmar distal radius plates [Königsee variable fixed-angle radius plate 7/3-hole, Königsee variable fixed-angle radius plate 5/3-hole (Allendorf, Germany), Medartis 2.5 Adaptive TriLock, Medartis 2.5 TriLock, Medartis 2.5 TriLock extraarticular, (Basel, Switzerland), Synthes VA-LCP distal two-column-radius, Synthes LCP extraarticular (Bettlach, Switzerland)] were investigated in 25 embalmed human cadaveric radii. An imprint of the space between the well-positioned plate and the distal radius was attained using a silicone mass and the maximum height of the silicone imprint was digitally measured. The mean maximum imprint height was compared between the seven plates using an analysis of variance with repeated measures and Bonferroni correction for multiple comparisons. RESULTS: The mean maximum distance between the plates and the radial cortex was <2 mm for all plates. The greatest difference was found with the Medartis Adaptive (1.99 ± 0.45 mm) and the least difference with the Synthes two-column (1.56 ± 0.76 mm), this difference being statistically significant (p = 0.005). CONCLUSION: Although there was no complete congruency between the plates and the radial cortex, all distal palmar radius plates investigated in this study presented a reasonable anatomical shape. The Synthes VA-LCP distal two-column-radius plate palmar showed the best anatomical fit. A low profile and optimized anatomical precontouring minimizes irritation of the surrounding soft tissues and should be considered with plate design and implant choice.

Sequence of the Essex-Lopresti lesion--a high-speed video documentation and kinematic analysis.

BACKGROUND AND PURPOSE: The pathomechanics of the Essex-Lopresti lesion are not fully understood. We used human cadavers and documented the genesis of the injury with high-speed cameras. METHODS: 4 formalin-fixed cadaveric specimens of human upper extremities were tested in a prototype, custom-made, drop-weight test bench. An axial high-energy impulse was applied and the development of the lesion was documented with 3 high-speed cameras. RESULTS: The high-speed images showed a transversal movement of the radius and ulna, which moved away from each other in the transversal plane during the impact. This resulted into a transversal rupture of the interosseous membrane, starting in its central portion, and only then did the radius migrate proximally and fracture. The lesion proceeded to the dislocation of the distal radio-ulnar joint and then to a full-blown Essex-Lopresti lesion. INTERPRETATION: Our findings indicate that fracture of the radial head may be preceded by at least partial lesions of the interosseous membrane in the course of high-energy axial trauma.

Percutaneous lateral ulnar collateral ligament reconstruction.

PURPOSE: Open surgical reconstruction of the lateral ulnar collateral ligament is the standard treatment for symptomatic posterolateral rotatory instability of the elbow. It involves dissection and retraction of the lateral elbow muscles, which have been shown to be secondary stabilizers of the lateral elbow. We introduce a new muscle-protecting technique for single-strand lateral ulnar collateral ligament reconstruction and report on the isometry and primary stability when compared with a conventional muscle-splitting procedure. It was hypothesized that percutaneous lateral ulnar collateral ligament reconstruction provided isometry over the range of motion and that stability was comparable with a conventional open procedure. METHODS: In sixteen human cadaver arms, the intact and the lateral collateral ligament complex-deficient situation was tested. Open lateral ulnar collateral ligament reconstruction was performed using a single-strand palmaris graft with humeral and ulnar tenodesis screw fixation. Posterolateral rotational stability was compared with a new reconstruction method, which percutaneously places a single-strand palmaris graft with humeral and ulnar tenodesis screw fixation. RESULTS: Both open and percutaneous lateral ulnar collateral ligament reconstruction provided isometry over the range of motion and restored posterolateral stability to that of the intact situation. No significant differences between open and percutaneous reconstruction were found. CONCLUSIONS: Percutaneous lateral ulnar collateral ligament reconstruction aims to preserve the lateral elbow muscles and to minimize soft tissue dissection. It has been shown that in an in vitro setup, this new procedure provides isometry over the range of motion and sufficiently restores posterolateral rotatory stability.

Locking-plate osteosynthesis versus intramedullary nailing for fixation of olecranon fractures: a biomechanical study.

PURPOSE: Intramedullary nailing and locked plating for fixation of olecranon fractures has recently gained popularity. However, these two new technologies have not been compared for their biomechanical efficacy. The aim of this study was to evaluate the biomechanical stability of two newly designed fracture fixation devices for treating olecranon fractures during dynamic continuous loading: the ION intramedullary locking nail and the LCP precontoured locking compression plate. METHODS: Simulated oblique olecranon fractures were created in eight pairs of fresh-frozen cadaver ulnae and stabilised using either the LCP or ION. Specimens were then subjected to continuous dynamic loading (from 25 to 200 N), with a continuous angle alteration between 0° and 90° of flexion, to perform a matched-pairs comparison. Significant differences in the distance between markers surrounding the fracture gap was determined using the Wilcoxon test after four and 300 loading cycles. RESULTS: The ION resulted in significantly less displacement in the fracture gap at 0° extension (P = 0.036), 45° flexion (P = 0.035) and 90° flexion (P = 0.017) after 300 cycles of continuous loading. The measured displacements were small and were probably not of clinical significance. No mechanical failure or hardware migration was seen with either fixation technique. CONCLUSION: This study shows significantly less micromotion for the ION than for the LCP in treating oblique olecranon fractures after 300 cycles of dynamic loading. Both implant types could be appropriate surgical techniques for fixation of selected olecranon fractures and osteotomies.

[Epicondylosis : Open surgical procedure-when and how for lateral and medial epicondylitis?] / Epikondylopathie des Ellenbogens : Offenes operatives Vorgehen ­ wann, wie für lateral und medial?

BACKGROUND: Epicondylosis of the elbow are common pathologies, with a higher incidence for radial epicondylosis. Approximately 90% are self-limiting under conservative treatment. TREATMENT: Multiple surgical procedures exist for the treatment of refractory cases. Arthroscopic treatment has been described for both radial and medial pathologies. Open and arthroscopic procedures show equivalent results in the surgical treatment of radial epicondylosis. This paper describes the most common open surgical procedures for the treatment of radial epicondylosis. Furthermore, the pros and cons of the arthroscopic versus the open approach are discussed, and the indications for an open surgical procedure for radial pathologies are highlighted. The authors believe that the open technique represents the standard treatment in the surgical treatment of ulnar epicondylosis. LIMITATIONS: Arthroscopic procedures have been described, but studies comparing the clinical outcome versus open surgical treatment are lacking. The anatomic proximity of the flexor origin to the ulnar nerve with the risk of iatrogenic damage is another limiting factor. In addition, concomitant pathologies on the ulnar side can better be ruled out preoperatively, so that arthroscopy has a rather low significance in the treatment of ulnar epicondylosis.

The anatomy of the proximal radius: implications on fracture implant design.

BACKGROUND: The proximal radius features a complex anatomy. Several studies have been published on the anatomy using different technical approaches; however, most of these studies were conducted with a special focus on parameters relevant to radial prosthetic design. The purpose of our study was to explore the complex geometry of the proximal radius with regard to fracture implant design. METHODS: Our computed tomography-based measurements of 78 multiplanar reformatted radii allow for exact assessment of its geometry and offer a scientific rationale towards the design of fracture implants. We conducted measurements on the radial head, the radial neck, the radial tuberosity, the radial head-to-neck angle, and the safe zone. RESULTS: A wide range of normal anatomy has been demonstrated for all parameters. Sex differences are statistically significant in all registered parameters, except the radial head-to-neck angle. Although measurements of maximum vs minimum radial head, neck, and tuberosity diameters show close correlation, diameter-to-length correlations, such as radial head diameter vs radial head height and radial neck diameter vs radial neck length, are low. CONCLUSIONS: Besides the wide range in size, intraindividual parameter variations have to be taken into account in the design of anatomically precontoured plates. The results of this study indicate that these plates will still need to offer the ability of "bend to match."