The risks of Kirschner wire placement in the distal radius: a comparison of techniques

Iatrogenic nerve injury during upper limb surgery (excluding the hand)

Nerve injury is the most feared complication of upper limb surgery. In about 17% of cases, the injury is iatrogenic and the potential for recovery is poor. In this context, patients file for compensation in about a quarter of cases. Defective patient installation or locoregional anaesthesia are rarely the cause of nerve injury. Nerves may be injured during creation of the surgical approach, implantation of the material or reduction of a traumatic injury. The injury is usually related to nerve release, retractor positioning or inappropriate limb-segment lengthening. Stretching and/or compression of a nerve trunk or branch is thus often the main cause. Among diagnostic tools, imaging studies (ultrasonography, computed tomography, and magnetic resonance imaging) provide information on nerve structure but not on the potential for recovery. Electromyography combined with a neurological examination establishes the diagnosis, guides the management strategy, allows nerve-function monitoring, and indicates when nerve repair or palliative surgery is indicated. Electromyography also has prognostic value, both at diagnosis and during follow-up, by showing whether nerve regeneration is taking place. When creating the surgical approaches, thorough familiarity with anatomic safe zones and nerve trajectories is crucial to ensure full control of the zones at highest risk for nerve injury. LEVEL OF EVIDENCE: IV.

Ultrasound Investigation of the Radial Nerve's Superficial Branch: Reducing the Risk of K-Wire Insertion Damage in Distal Radius Fractures

BACKGROUND

Kirschner wire (K-wire) insertion during surgery for distal radius fractures carries a risk of damaging the radial nerve's superficial branch. In this prospective study, we investigated the relationship between the radial nerve's superficial branch and the radius using ultrasound to minimize risk.

METHODS

We collected data from 101 healthy volunteers (202 limbs; 51 men; mean age: 40.6 years). We ultrasonographically assessed the courses of the radial nerve's dorsal and superficial palmar branches at 0, 1, 2, and 3 cm proximal to the radial styloid process tip. The positional relationship between the radial nerve's superficial branch and the radius was determined by splitting the radius's ultrasound map into 4 sections (R1-R4) from the palmar side. The section containing the dorsal and palmar branch midpoints was determined for each height.

RESULTS

In many limbs, the dorsal branch tended to wrap from the proximal palmar to the distal dorsal side at 1 to 2 cm proximal to the radial styloid process tip. In approximately 90% of limbs, the palmar branch ran along the radius's palmar side rather than the radial surface.

CONCLUSIONS

A small incision enabling direct view may be the best approach for avoiding nerve damage when the superficial branch is less than or equal to 2 cm proximal to the tip of the radial styloid process. Inserting the K-wire from the dorsal side of the radius may be safer for more proximal locations. We recommend a preoperative ultrasound examination to determine the course of the superficial branches of the radial nerve in each patient.

Evaluation of a New Virtual Reality Concept Teaching K-Wire Drilling With Force Feedback Simulated Haptic in Orthopedic Skills Training

PURPOSE

Surgical simulations are becoming increasingly relevant in musculoskeletal training. They provide the opportunity to develop surgical skills in a controlled environment while reducing the risks for patients. For K-wire internal fixation in musculoskeletal surgery, a force feedback virtual reality (VR) simulator was developed. The aim of this study was to evaluate training results using this technology and compare the results with that of standard teaching on cadavers.

METHODS

Twenty participants attending an AO Trauma Course during 2020 were randomly allocated in 2 groups. On day 1, group A was trained by senior surgeons using a cadaver and group B was trained by the VR simulator for K-wire insertion in the distal radius. On day 2, all participants performed K-wire insertion on the cadaver model, without assistance, to validate the training effect.

RESULTS

On a surgical skills test, group B performed better than group A. In group B, the entry point of the first K-wire was closer to the targeted styloid process of the radius, and the protrusion of the K-wires into soft tissue was less than that in group A.

CONCLUSIONS

Training with the VR simulator for K-wire insertion resulted in better surgical skills than training by a surgeon and cadaver model.

CLINICAL RELEVANCE

Training with the VR simulator provides the opportunity to improve and refine surgical skills without the risk of harming patients. It offers easier access, unlimited repetitions, and is more cost-effective compared with training sessions with cadavers.

An Analysis of the Structures at Risk from Percutaneous Pinning of Distal Radius Fractures and a Comparison of Two Pinning Techniques: A Cadaveric Study

Background: A stab incision and blunt dissection prior to wire placement are believed to decrease the risk of injury to underlying structures during percutaneous pinning of distal radius fractures (DRF). However, only a few studies have compared stab incision and blunt dissection to direct wire placement. The aim of this cadaveric study is to analyse the structures at risk during percutaneous pinning of DRF and compare the two methods of wire placement.

Methods: A total of 10 cadavers (20 upper limbs) were divided into two groups of five each. Five 2.0 mm Kirschner (K)-wires were inserted into the distal radius under fluoroscopic control in a standard fashion to simulate percutaneous pinning of DRF. In group 1, the K-wires were inserted directly, whereas in group 2, the wires were inserted after making a stab incision and blunt dissection to reach the bone. Each cadaveric limb was then dissected carefully to measure the distance of the K-wires from the branches of the superficial radial nerve (SRN), the cephalic vein and the first dorsal compartment and to determine the structures injured (pierced or in close contact) by the K-wires.

Results: Out of the 100 K-wires placed, 18 wires were in close contact or pierced an underlying structure. These included 11 wires injuring tendons, six wires injuring branches of the SRN and one wire injuring the cephalic vein. Direct wire placement (group 1) resulted in injury to eight structures (44.4%) while stab incision and blunt dissection prior to wire placement (group 2) resulted in injury to 10 structures (55.5%). This difference was not statistically significant.

Conclusions: Percutaneous pinning of DRF is associated with a high risk of injury to the extensor tendons and branches of the SRN. This risk is not reduced by making a stab incision and blunt dissection prior to K-wire placement.

Mini-invasive Osteotomy for Pediatric Distal Radius Malunion

Although most malunions after pediatric distal radius fractures will remodel as the child grows, adolescent patients with severe malunion and limited growth require reduction to restore alignment. The authors technique for a mini-invasive osteotomy is presented. The apex of the malunion is approached from a single 2 cm volar incision through the flexor carpi radialis sheath. Open wedge osteotomy is performed. The osteosynthesis is secured with an individually contoured T-plate. The procedure was used to correct a severe visible malunion in a 12-year-old girl. Normal alignment was achieved with no nerve or tendon injury or irritation, infection, refracture, or any other complication. Mini-invasive osteotomy with a volar plate is a feasible method for experienced hand surgeons for the treatment of distal radius malunion in adolescents.

Safe zone of pin insertion for nonbridging external fixators in distal radial fractures: MRI analysis

BACKGROUND

Of the anatomical reduction and fixation methods used to treat distal radius fracture, non-bridging external fixation has the advantage of enabling early wrist motion. The surgical technique relies on successful placement of the pin in individual fracture fragments. The present study aimed to identify the safe zone of pin insertion for a non-bridging external fixator into the distal radius that avoids metal impingement of extensor tendons.

METHODS

The width and length of the septal attachments of the extensor retinaculum were measured on axial MR images of 62 wrists.

RESULTS

The 2-3 septum was the widest and longest, with a width of 2-7 mm and a location 0-36 mm proximal to the wrist joint. The width of the 1-2 septum was 2-6 mm, and was widest at 10 mm proximal to the joint. The 1-2 septum was triangular-shaped, while the 2-3 septum was oval-shaped. The 3-4 and 4-5 septa had narrow attachments and were adequate for pin insertion (with a pin 1-2 mm in width) at a position less than 8 mm proximal to the wrist. The width of the 1 R septum (radial to the 1st septum) was 2-6 mm at the radiovolar aspect of the wrist.

CONCLUSIONS

There were two safe pin insertion sites; the first was safe at the distal aspect only (8-10 mm proximal to the wrist) and included the 1-2, 3-4, and 4-5 septa, while the second was safe from 0 mm to 32-38 mm proximal to the wrist and included the 1 R and the 2-3 septa. The 1 R septum had adequate size for use as a new pin insertion site that aligns in the internervous plane and has minimal risk of superficial radial nerve injury.

Corrosion and bone healing of Mg-Y-Zn-Zr-Ca alloy implants: Comparative in vivo study in a non-immobilized rat femoral fracture model

Biodegradable magnesium (Mg) alloys exhibit improved mechanical properties compared to degradable polymers while degrading in vivo circumventing the complications of permanent metals, obviating the need for surgical removal. This study investigated the safety and efficacy of Mg-Y-Zn-Zr-Ca (WZ42) alloy compared to non-degradable Ti6Al4V over a 14-week follow-up implanted as pins to fix a full osteotomy in rat femurs and as wires wrapped around the outside of the femurs as a cerclage. We used a fully load bearing model allowing implants to intentionally experience realistic loads without immobilization. To assess systemic toxicity, blood cell count and serum biochemical tests were performed. Livers and kidneys were harvested to observe any accumulation of alloying elements. Hard and soft tissues adjacent to the fracture site were also histologically examined. Degradation behavior and bone morphology were determined using micro-computed tomography scans. Corrosion occurred gradually, with degradation seen after two weeks of implantation with points of high stress observed near the fracture site ultimately resulting in WZ42 alloy pin fracture. At 14 weeks however, normal bone healing was observed in femurs fixed with the WZ42 alloy confirmed by the presence of osteoid, osteoblast activity, and new bone formation. Blood testing exhibited no significant changes arising from the WZ42 alloy compared to the two control groups. No recognizable differences in the morphology and more importantly, no accumulation of Mg, Zn, and Ca in the kidney and liver of rats were observed. These load bearing model results collectively taken, thus demonstrate the feasibility for use of the Mg-Y-Zn-Zr-Ca alloy for long bone fracture fixation applications.

Neurologic complications in common wrist and hand surgical procedures

Nerve dysfunction after upper extremity orthopedic surgery is a recognized complication, and may result from a variety of different causes. Hand and wrist surgery require incisions and retraction that necessarily border on small peripheral nerves, which may be difficult to identify and protect with absolute certainty. This article reviews the rates and ranges of reported nerve dysfunction with respect to common surgical interventions for the distal upper extremity, including wrist arthroplasty, wrist arthrodesis, wrist arthroscopy, distal radius open reduction and internal fixation, carpal tunnel release, and thumb carpometacarpal surgery. A relatively large range of neurologic complications is reported, however many of the studies cited involve relatively small numbers of patients, and only rarely are neurologic complications included as primary outcome measures. Knowledge of these neurologic outcomes should help the surgeon to better counsel patients with regard to perioperative risk, as well as provide insight into workup and management of any adverse neurologic outcomes that may arise.

Echography-Guided Pinning for Prevention of Iatrogenic Injuries to the Radial Nerve during Fixation of Extra-articular Distal Radius Fracture: An Anatomical Study

This study assesses the usefulness and feasibility of an osteosynthesis of the lower end of the radius under ultrasound imaging to avoid the superficial branch of the radial nerve (SBRN). A single operator performed an initial echography of the wrist of 12 cadaveric upper limbs to identify the three main branches of the SBRN and the tendons. Then, three pins were placed according to Kapandji's procedure, avoiding the structures spotted under ultrasound imaging. After dissection, the safety distances for the branches of the SBRN, dorsal extensor tendons, and veins were measured, and injuries to these structures were noted. No lesion of the SBRN was found with an average safety distance of 8.1 for the third branch of the radial nerve (SR3) and 1.3 mm for the first and the second branches of the radial nerve (SR1-2). Three tendons were spiked. The average operative time was 38.3 minutes. Ultrasound secures percutaneous surgery to avoid the branches of the SBRN but requires a learning curve.

Anatomical Variants of Lister's Tubercle: A New Morphological Classification Based on Magnetic Resonance Imaging

Objective

Lister's tubercle is used as a standard anatomical landmark in hand surgery and arthroscopy procedures. In this study, we aimed to evaluate and propose a classification for anatomical variants of Lister's tubercle.

Materials and Methods

Between September 2011 and July 2014, 360 MRI examinations for wrists performed using 1.5T scanners in a single institution were retrospectively evaluated. The prevalence of anatomical variants of Lister's tubercle based on the heights and morphology of its radial and ulnar peaks was assessed. These were classified into three distinct types: radial peak larger than ulnar peak (Type 1), similar radial and ulnar peaks (Type 2) and ulnar peak larger than radial peak (Type 3). Each type was further divided into 2 subtypes (A and B) based on the morphology of the peaks.

Results

The proportions of Type 1, Type 2, and Type 3 variants in the study population were 69.2, 21.4, and 9.5%, respectively. For the subtypes, the Type 1A variant was the most common (41.4%) and conformed to the classical appearance of Lister's tubercle; whereas, Type 3A and 3B variants were rare configurations (6.4% and 3.1%, respectively) wherein the extensor pollicis longus tendon coursed along the radial aspect of Lister's tubercle.

Conclusion

Anatomical variations of Lister's tubercle have potential clinical implications for certain pathological conditions and pre-procedural planning. The proposed classification system facilitates a better understanding of these anatomical variations and easier identification of at-risk and rare variants.

An Anatomical Study to Demonstrate the Proximity of Kirschner Wires to Structures at Risk in Percutaneous Pinning of Distal Radius Fractures

Distal radius fractures are often treated using percutaneous Kirschner wires (K-wires). The sensory nerves in this area, extensor tendons, radial artery and cephalic vein are at risk of injury in this procedure. We undertook a cadaveric investigation to identify probability of damage to these 'at risk' structures by measuring their distances in relation to standard K-wire sites. Nine upper limbs from six formalin-preserved cadavers were studied. Four K-wires were placed percutaneously simulating fixation of a distal radius fracture. Careful dissection was done preserving the original position of neurovascular and tendinous structures. Distances to relevant soft-tissue structures from each K-wire were measured using an electronic digital caliper. Distance of superficial nerves from radial styloid and Lister's tubercle was measured to determine their 'safe distance' from these fixed landmarks. None of the superficial nerves were injured by a K-wire. Cephalic vein had been pierced on 4 occasions (4/18) and extensor tendons on 3 occasions (3/18). Wilcoxon signed-rank test was used to compare distance of the superficial nerves from radial styloid and Lister tubercle, and the latter was found to be the safer option. This study highlights the inherent danger in percutaneous K-wire fixation of wrist fractures. Limited size of the area, where K-wires can be positioned, and anatomic variations of neurovascular structures pose obstacles in developing guidelines for reducing risk of injury. We advocate use of mini-open approach and guiding devices to avert complications of inadvertent impalement and damage to these structures.

Is there a safe zone to avoid superficial radial nerve injury with Kirschner wire fixation in the treatment of distal radius? A cadaveric study

AIM OF THE STUDY

To determine the relation of the superficial radial nerve to bony land-marks and to identify a safe zone for K-wire pinning in the distal radius.

METHOD

The superficial radial nerve was dissected in sixteen upper extremities of preserved cadavers.

RESULTS

We found that the superficial radial nerve emerged from under brachioradialis at a mean distance of 8.45 (±1.22) cm proximal to the radial styloid. The mean distance from the first major branching point of the superficial radial nerve to the radial styloid were 4.8 ± 0.4 cm. All branches of the superficial radial nerve were found to lie in the radial half of an isosceles triangle formed by the radial styloid, Lister's tubercle and the exit point of the superficial radial nerve. There is an elliptical area just proximal to the Lister's tubercle. This area is not crossed by any tendons or nerve. It is bounded by the extensor carpiradialis brevis, extensor pollicis longus.

CONCLUSION

Pinning through the radial styloid is unsafe as the branches of the superficial radial nerve passé close to it. The ulnar half of the isosceles triangle is safe regarding the nerve. The elliptical zone just proximal to the Lister's tubercle is safe regarding the tendons and nerve.

Treatment of distal radial fractures with antegrade intra-medullary Kirschner wires

The treatment of unstable Colles-type distal radial fractures remains a challenge. A prospective study was conducted to evaluate the outcomes of the treatment of unstable distal radial fractures using antegrade intra-medullary K-wires. Twenty-eight Colles-type distal radial fractures were selected excluding comminuted intra-articular and Barton’s fractures. The blunt tips of intra-medullary K-wires were introduced in an antegrade direction to support the subchondral bone of the distal fragment. The scoring system of Green and O’Brien modified by Cooney et al. was used for the final clinical evaluation. The radiological outcomes were evaluated using the scale proposed by Stewart et al. After a mean follow-up of 34 months (range 14–46), 17 patients were rated clinically excellent, seven good, three fair and one poor. The mean loss of radial height, radial inclination, volar tilt and ulnar variance was 0.9 mm, 1.9°, 0.5° and 0.4 mm, respectively. These results were comparable with the values reported in other pinning studies. Only one patient complained of skin irritation and painful bursitis in the forearm; otherwise, no complications related to tendon or nerve injury were encountered. One patient had protrusion of K-wire into the wrist joint. The technique proved to be effective in maintaining reduction in distal radial fracture with low rate of soft tissue complications.

Volume rendering of three-dimensional fluoroscopic images for percutaneous scaphoid fixation: an in vitro study

Percutaneous fixation of scaphoid fractures offers potential advantages to cast treatment but can be difficult to perform with conventional two-dimensional imaging. This study aimed to evaluate the use of a novel navigation technique using volume-rendered images derived from intraoperative cone-beam computed tomography imaging, without the need for typical patient-based registration. Randomized in vitro trials in which a guidewire was inserted into a scaphoid model were conducted to compare volumetric navigation to conventional fluoroscopic C-arm (n = 24). Central wire placement, surface breach, procedure time, drilling attempts, and radiation exposure were compared between groups. Compared to conventional percutaneous insertion, navigation achieved equal or significantly better placement of the guidewire with fewer drilling attempts and less radiation exposure. On average, navigation took 74 s longer to perform than the conventional method, which was statistically significant but clinically irrelevant. This evaluation suggests that the technology is promising and may have many clinical benefits including improved fixation placement, fewer complications, and less radiation exposure. The intraoperative workflow is more efficient and eliminates the need for preoperative computed tomography, image segmentation, and patient-based registration typical of traditional navigated procedures.

Fixation of distal radius fractures in adults: a review

In patients for whom function is a priority, anatomic reduction and stable fixation are prerequisites for good outcomes. Several therapeutic options exist, including orthopedic treatment and internal fixation with pins (intra- and extrafocal), external fixation which may or may not bridge the wrist, and different internal fixation techniques with dorsal or palmar plates using or not, locking screws. Arthroscopy may be necessary in case of articular fracture. In the presence of significant metaphyseal bone defects, filling of the comminution with phosphocalcic cements provides better graft stability. The level of evidence is too low to allow recommending one type of fixation for one type of fracture; and different fixation options to achieve stable reduction exist, each with its own specific complications. With the new generations of palmar plate, secondary displacement is becoming a thing of the past.

Complications of Kirschner-wire fixation in distal radius fractures

Distal radius and ulna fractures are the most common fractures seen in England, occurring at a rate of 22/10,000 person years. Kirschner (K)-wire fixation is a well-accepted method of treating these fractures. There is a surprising paucity of evidence on the subject of prophylactic antibiotics and the duration of K wires can be left in, as these relate to infection rates. We therefore present the results of our protocol for distal radius K-wire fixation for which: no antibiotic prophylaxis was given; we used a percutaneous (not buried) technique, where the K wires were removed after 4 weeks, and the patient has a total of 6 weeks in cast (last 2 wk without wires). The results of the last 100 consecutive patients who were treated with manipulation and K wiring of dorsally displaced distal radial fractures in a standard district general hospital over a 2-year period were analyzed retrospectively. A total of 100 patients had 176 K wires inserted. The mean age was 32.5 years. The mean time to pin removal was 29.4 days. The infection rate was 2%. These results illustrate a safe and clinically effective protocol for K-wire fixation in treating distal radius fractures. On the basis of this study, we do not advocate the use of prophylactic antibiotics, postulating that they do not affect infection rate and thereby eliminating potential antibiotic adverse effects. Furthermore, we do not bury the K wires, which allows for their removal in clinic, thus preventing risks of further operative procedures.

Radial styloid fractures

Radial styloid fractures can occur in isolation or in association with other injuries, including complex intra-articular distal radius fractures, carpal fractures, carpal dislocations, and radiocarpal dislocations. The anatomy surrounding the radial styloid is complex, and complications related to surgical approach, treatments, and symptomatic hardware can occur. Operative treatments vary according to the injury pattern present, and pattern recognition is the key to optimizing treatment of these injuries. Outcomes are related to the precision of the reconstruction as well as the magnitude of the injury; better results are associated with lower-energy patterns.

Evaluation of the safe zone for percutaneous Kirschner-wire placement in the distal radius: Cadaveric study

Distal radius fractures are a common injury that is often reduced with percutaneous K-wires. The sensory nerves in this area are at risk of injuring from pin placement. Cadaveric studies of the nerve distribution patterns have elucidated certain safe zones for pin placement that limits the risk of sensory nerve injury. These studies have advocated a limited open technique that involves a shallow incision followed by blunt dissection to the bone before a k-wire is drilled into the radius. A previously identified safe zone in the anatomical snuffbox was evaluated in 40 cadaver wrists for k-wire placement via a percutaneous technique that involves putting the pin directly through the skin without an incision or blunt dissection. After k-wire placement each wrist was dissected and sensory nerve distribution relative to the pin placement was evaluated. The variability of the distribution of the sensory nerves, namely the lateral antebracheal cutaneous nerve and the superficial branch of the radial nerve, is such that no truly safe zone exists for pin placement with the percutaneous technique in this area.

Distal radius fractures: nonoperative and percutaneous pinning treatment options

Nonoperative treatment of distal radial fractures by reduction and immobilization remains the most common treatment, based on the incidence of appropriate fracture types, as seen in many epidemiological studies in the literature. In this article, the indications, technique, predictors of failure, outcomes, and complications are reviewed. A variety of treatment options have been proposed for distal radial fractures that are predicted, or subsequently identified, to be too unstable for nonoperative management. Percutaneous pinning is an effective option for select fractures. The authors also review the indications, described techniques, complications and outcomes associated with this treatment option.

Percutaneous pinning of distal radius fractures: an anatomic study demonstrating the proximity of K-wires to structures at risk

PURPOSE

Closed reduction and percutaneous pinning is a reliable technique for treating 2- and 3-part distal radius fractures. There are currently no data that demonstrate the proximity of at-risk nerves and tendons during percutaneous placement of 5 commonly used K-wires. Whereas the previous literature notes the risk of superficial radial nerve injury with K-wire insertion into the radial styloid, the current study provides specific distances, not only to the superficial radial nerve (SRN) but also to the tendons of the first through fifth extensor compartments during K-wire insertion.

METHODS

K-wires (1.5 mm or 0.059 in) were placed percutaneously into the distal radius of 15 cadaver specimens, simulating fixation of a distal radius fracture. After dissection, the distance from the K-wires to the extensor tendons and branches of the SRN were measured and tabulated.

RESULTS

The volar radial styloid K-wire was an average distance of 1.47 mm +/- 1.7 from the closest branch of the SRN. One penetrated a branch of the SRN. The dorsal radial styloid K-wire was an average distance of 0.35 mm +/- 0.64 from the closest branch of the SRN. No tendons in the first compartment were found penetrated by or touching the K-wires. The transverse radial K-wire was an average distance of 1.07 mm +/- 1.57 from the branches or trunk of the SRN. One K-wire was found piercing the volar branch of the SRN, and 1 K-wire was found piercing the abductor pollicis longus. The dorsal rim K-wire was an average of 2.94 mm +/- 2.11 from the ulnar aspect of the extensor pollicis longus and an average of 1.44 mm +/- 1.65 from the radial aspect of the extensor digitorum communis. The dorsoulnar K-wire was an average distance of 1.88 mm +/- 1.6 ulnar or radial to the extensor digiti quinti proprius and penetrated it in three specimens.

CONCLUSIONS

The volar radial styloid, transverse radial, and dorsoulnar K-wires all penetrated either tendons or nerves. It is therefore prudent to make a small incision to identify and protect the underlying structures prior to placement of K-wires used for the fixation of distal radius fractures. Also, care must be taken not to place the dorsal K-wires more than 5 mm ulnar to Lister's tubercle to avoid extensor digitorum communis injury.

THE SUPERFICIAL BRANCH OF THE RADIAL NERVE: A MORPHOLOGIC STUDY

Study the morphology of the superficial branch of the radial nerve (SBRN) of the forearms and wrists of fresh adult human cadavers. Methods: Twenty three dissections were performed under 3.5x loupe magnification, histological sections of the nerve were obtained in 20 dissections for fascicle identification. Results: The SBRN emerged, in average, at 8.65cm proximal to the radial styloid apophysis (RSA) between the Brachioradialis (BR) and Extensor Carpi Radialis Longus (ECRL) tendons. In 6/23 cases the SBRN emerged between an accessory BR tendon and the main BR tendon. The first branch of the SBRN arose at an average of 4.58 cm proximal to the RSA. A branch running across the RSA was found in 7/23 cases. At that level, the average number of branches crossing the wrist was 3.4. A fascicle count of the nerve and its first branch showed an average of 6.6 and 4.0 fascicles, respectively. Conclusion: Our anatomical findings are similar to those in the revised literature and contribute towards a better knowledge of the SBRN. Great caution is required in surgical procedures such as percutaneous bone fixation of the distal 1/3 of the forearm and wrist and particularly, in those susceptible to SBRN injury, as in seven of the 23 cases the SRBN ran directly accross the RSA. The authors recommend performing small longitudinal incisions down to the subcutaneous tissue, separating the nerve branches by blunt soft tissue dissection, with a delicate haemostat, before introducing the Kirschner wires (minimally invasive procedures).

Ulnocarpal stabilization in the management of comminuted fractures distal end radius

BACKGROUND

Malunion due to progressive radial collapse during healing is a common complication following comminuted fracture distal radius treated by conventional methods. Many treatment modalities have been described with their own merits and demerits. Stabilization of ulnocarpal articulation is an effective method to prevent radial collapse during healing, and hence this study.

MATERIALS AND METHODS

A prospective study of 200 patients of comminuted intraarticular fracture lower end radius between 20-75 years of age irrespective of sex, treated by closed reduction and percutaneous stabilization of ulnocarpal articulation and a well-molded above elbow POP cast for 6 weeks has been presented. Patients were evaluated at 1 year follow-up and functionally by Sarmiento's modification of Lindstrom criteria and Gartland and Werley's criteria.

RESULTS

Excellent to good results were seen in 92%, fair in 6% and poor in 2% of the cases. Complications observed were, pintract infection (n = 6), malunion (n = 6), subluxation of the inferior radioulnar joint (n = 4) Sudeck's osteodystrophy (n = 3) and post-traumatic arthritis of the wrist (n = 3).

CONCLUSION

Percutaneous fixation by this technique is an effective method to maintain the reduction, prevent radial collapse during healing, and to maintain the stability of the distal radioulnar joint even when the fracture is grossly comminuted, intraarticular, or unstable.

Treatment of distal radius fractures with percutaneous pinning and pin-in-plaster

This article describes a modified technique that combines percutaneous pinning and casting. A prospective study was conducted on 54 patients with distal radius fracture who were treated with percutaneous Kirschner wire (K-wire) fixation and pin-in-plaster technique. The surgical indications of this technique included displaced extra-articular fracture, intra-articular fracture without significant comminution, and articular step-off less than 2 mm. The average radial height was 10.96 mm, and the volar tilt was 3.97 degrees on immediate postoperative radiographs. Upon removal of pin-in-plaster and percutaneous K-wires, the average radial height was 9.92 mm, and the volar tilt was 3.93 degrees . Bony union was achieved in all patients; the satisfaction rate was 90.7%. Pin-in-plaster technique is effective for maintaining reduction during bone healing. The procedure provides the ability to achieve anatomic reduction and then maintains this reduction through an adequate method of immobilization.

Keeping osteocytes alive: a comparison of drilling and hammering k-wires into bone

In this study, the insertion time and histological effects of drilling and hammering K-wires into bone are described. The insertion time was measured while drilling or hammering K-wires into the femurs and tibias of ten rabbits. Four K-wires, inserted into one hind limb, were used for histological examination directly after insertion and four K-wires inserted into the contralateral hind limb were used for the same measurements 4 weeks later. The specimens were scored for presence, or absence, of osteocytes, fragmentation of the bone edges, haemorrhage, microfractures, cortical reaction and callus formation around the pin track. The insertion time needed for drilling in K-wires was significantly longer than that of hammering. Drilling also resulted in the disappearance of the osteocytes in almost all sections while hammering did not have this effect but did result in more microfractures. Hammering K-wires may be a superior technique because it prevents osteonecrosis and requires a shorter insertion time.

Extensor tendon injury to the index and middle finger secondary to Kirschner wire insertion for a distal radial fracture

We describe a case with the highly unusual complication of attritional ruptures to both the extensor tendons to the index and middle finger following Kirschner wire placements for a distal radial fracture. This particular complication has never been previously described in the literature. We also review the literature, identifying certain techniques in the management of distal radial fractures with Kirschner wires which are considered to increase the risk of tendonous or neurovascular injury. Finally, recommendations are made that should reduce the complications of iatrogenic soft tissue injury associated with this very common procedure.

Applied anatomy of the superficial branch of the radial nerve

The superficial branch of the radial nerve (SBRN) is highly vulnerable to trauma and iatrogenic injury. This study aimed to map the course of the SBRN in the context of surgical approaches and identify a safe area of incision for de Quervain's tenosynovitis. Twenty-five forearms were dissected. The SBRN emerged from under brachioradialis by a mean of 8.31 cm proximal to the radial styloid (RS), and remained radial to the dorsal tubercle of the radius by a mean of 1.49 cm. The nerve divided into a median of four branches. The first branch arose a mean of 4.92 cm proximal to the RS, traveling 0.49 cm radial to the first compartment of the extensor retinaculum, while the main nerve remained ulnar to it by 0.64 cm. All specimens had branches underlying the traditional transverse incision for de Quervain's release. A 2.5-cm longitudinal incision proximal from the RS avoided the SBRN in 17/25 cases (68%). In 20/25 specimens (80%), the SBRN underlay the cephalic vein. In 18/25 (72%), the radial artery was closely associated with a sensory nerve branch near the level of the RS (SBRN 12/25, lateral cutaneous nerve of the forearm (LCNF) 6/25.) A longitudinal incision in de Quervain's surgery may be preferable. Cannulation of the cephalic vein in the distal third of the forearm is best avoided. The close association between the radial artery and first branch of the SBRN or the LCNF may explain the pain often experienced during arterial puncture. Particular care should be taken during radial artery harvest to avoid nerve injury.

Distal radius fractures: nonoperative and percutaneous pinning treatment options

Nonoperative treatment of distal radial fractures by reduction and immobilization remains the most common treatment, based on the incidence of appropriate fracture types, as seen in many epidemiological studies in the literature. In this article, the indications, technique, predictors of failure, outcomes, and complications are reviewed. A variety of treatment options have been proposed for distal radial fractures that are predicted, or subsequently identified, to be too unstable for nonoperative management. Percutaneous pinning is an effective option for select fractures. The authors also review the indications, described techniques, complications and outcomes associated with this treatment option.

Combined internal and external fixation of distal radius fractures

Combined internal and external fixation of distal radius fractures is used most commonly to treat injuries with joint surface or metaphyseal comminution. External fixation aids reduction intraoperatively and facilitates arthroscopic, per-cutaneous, or open manipulation of the fracture. Internal fixation maintains precise reduction of critical anatomy, principally the contour and orientation of the articular surface. Postoperatively the fixator functions as a neutralization device, preventing fracture collapse and decreasing the biomechanical demands on the internal fixation hardware. The combined technique exploits the benefits of both forms of fixation, allowing each to be used to full advantage in the treatment of complex distal radius fractures.

Treatment of unstable extra-articular distal radius fractures by modified intrafocal Kapandji method

The authors prospectively assess the results of surgically treated, unstable extra-articular distal radius fractures from 29 patients with good bone quality. Mean age was 49 years, ranging from 22 to 69 years; the female gender was the most frequently affected (58.6% of the cases). Surgical fixation was indicated for fractures presenting an angulation above 20 degrees , marked dorsal comminution, and radius shortening in excess of 10 mm on initial x-rays (anteroposterior and lateral views). The Kapandji technique, with intrafocal, nonthreaded Kirschner wires, was employed. Clinical data assessed anatomic aspects according to Scheck, functional aspect after Gartland and Werley, strength by Scheck's methods, and esthetic by Frykman's criteria. Functional assessment, according to Gartland and Werley, revealed 72.1% of excellent and good results at 3 months; 89.7% at 6 months; and 96.6% at 12 months. Immediate postoperative reduction was not maintained at the final follow-up at 12 months; however, that loss was not severe, and the anatomic outcome was good and excellent in 96.6% of the cases. Six patients presented complications. Four patients presented reflex sympathetic dystrophy; 1 patient had a superficial Kirschner wire infection, and another patient had radial nerve superficial branch paresthesia. The employed technique showed to be effective in the treatment of unstable, extra-articular fractures of the distal radius. It is easy to learn and to perform. The device employed has a low cost and is widely available in operation rooms.

Superficial radial nerve damage due to Kirschner wiring of the radius

For displaced fractures of the radius, the use of Kirschner wires (K Wires) is accepted practice either alone or to supplement external fixation. Complications related to K wires include infection, migration and damage to tendons and nerves. We set out to investigate to incidence of superficial radial nerve damage due to radial styloid K wires. Injury to the sensory branch of the superficial radial nerve was seen in eight (20%) out of the 40 patients. K wiring is a popular technique to help maintain anatomic reduction of distal radial fractures. It has the advantage of being a semi-closed procedure, which is simple to perform. However, the morbidity of nerve damage is often underestimated and can be avoided.

Mechanical evaluation of a porous bone graft substitute based on poly(propylene glycol-co-fumaric acid)

A porous, resorbable polymer composite based on poly(propylene glycol-co-fumaric acid) (PPF) was mechanically evaluated in vitro for use as a bone graft substitute and fracture fixative. The test material created a dynamic system capable of initially providing mechanical integrity to bony voids and a degradative mechanism for ingrowth by native bone. The unsaturated polymer, PPF, was crosslinked in the presence of effervescent agents to yield a porous microstructure upon curing. An in vitro degradation study first assessed the temporal mechanical properties of the test material. This research was followed by an ex vivo study using a long-bone osteotomy model to characterize the mechanics of fixation. Results showed the initial compressive strength of the cross-linked PPF system was comparable to cancellous bone. The rate of strength loss was commensurate with the predicted mechanical recovery of healing bone with analogous results in a composite that comprised also 25% (by weight) autograft. Mechanical testing in the long-bone model demonstrated that PPF-based bone-graft substitute increased the flexural strength of K-wire stabilized osteotomies. These results suggest that this type of bone graft substitute may have clinical utility in the stabilization of complex tubular bone fractures.

Antegrade intramedullary K-wire fixation for distal radial fractures

Manual reduction and antegrade intramedullary K-wire fixation were performed for 29 selected Colles-type distal radial fractures in 29 patients. Severely comminuted intra-articular fractures and Barton's fracture were not included in this study. The tips of the K-wires supported an articular surface of the distal radius. Except for 1 case of skin irritation in the forearm, there were no complications related to tendon or nerve injuries or reflex dystrophy. There was no pin loosening, but protrusion of sharp tips of K-wires into the wrist joint occurred in 3 patients. Average volar tilt, radial shortening, and step-off at follow-up evaluation were 5 degrees, 2.6 mm, and 0.2 mm, respectively. These radiologic results were consistent with values reported in other pinning studies; however, radial shortening was not controlled effectively. Fourteen (48%) of 29 patients had radial shortening >3 mm. The advantages of this surgical procedure are the low occurrence rate of soft-tissue complications and prevention of dorsal angulation of fractures.

Mechanical strength of intramedullary pinning and transfragmental Kirschner wire fixation for Colles' fractures

Four methods of distal radius fracture fixation were tested in this experimental biomechanical study of an unstable Colles' fracture model. Sixty artificial radial bones and seven pairs of cadaveric radii were used. Seven additional pairs of paired cadaveric radial epiphyses were used in separate perforation and cut-out tests. Tests with the artificial bones showed that the rigidity of the four tested fixation methods was comparable, except for proximal intramedullary pinning. The rigidity of the NODE fixation in the cadaveric radii was greater than that of transfragmental pinning. The load at failure was significantly greater for the NODE system than for the Kirschner wire models. Rigidity and failure loads showed a positive correlation with bone mineral density. The current study indicates the NODE system was the strongest of the fixation methods.

Percutaneous treatment of carpal, metacarpal, and phalangeal injuries

Percutaneous fixation of hand fractures is a common technique that takes advantage of the subcutaneous nature of hand bones, their small size, and their limited loading potential for stress placed on hardware. Percutaneous wire fixation supplements cast fixation when plaster cannot hold particular reductions, and allow surgical fixation with limited postoperative swelling. In the first part of the current study, the types of wires that are used for hand fixation, fluoroscopy, helpful instruments, and the basic techniques used for this type of surgery are discussed. In the second part of the study, specific fixation techniques for different fractures of the carpals, metacarpals, and phalanges are outlined.