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

Complications of operatively treated distal radial fractures

Distal radial fractures represent the most common fractures of the upper extremity. Operative treatment is performed for approximately one-third of distal radial fractures in the adult population. Complications following operative treatment of distal radial fractures vary depending on the treatment modality and can be stratified into preoperative and postoperative complications. Complications can occur in the near, intermediate and long term. The most common complications seen are tendon irritation and rupture, chronic regional pain syndrome (CRPS), carpal tunnel syndrome, ulnar or radial neuropathy, compartment syndrome, malunion, inadequate fixation or loss of fixation, symptomatic hardware, post-traumatic arthritis, stiffness and infection. Careful planning, treatment and patient selection can help to mitigate these complications.Level of evidence: V.

The access route through the anatomical snuffbox in ultrasound-guided synovial biopsy of the wrist allows for a safe and effective collection of tissue samples in inflammatory arthritis

BACKGROUND

A proof-of-concept study to evaluate the feasibility and safety of minimally invasive ultrasound (US)-guided synovial biopsy of the radiocarpal (RC) joint using the anatomical snuffbox as an access route.

METHODS

Twenty consecutive patients with active chronic arthritis of the wrist underwent minimally invasive US-guided synovial biopsy of the RC joint using the anatomical snuffbox as the access route. Samples were retrieved from 3 predetermined biopsy target sites of the RC synovia (proximal, vault, and distal site), aiming for a minimum of 12 samples. The procedure's feasibility was evaluated based on the number and histological quality of retrieved tissue fragments tested on pre-defined histometric parameters. The safety and tolerability of the procedure were assessed through 1-week and 1-month follow-up clinical evaluations.

RESULTS

A median number of 17 fragments (≥ 1 mm diameter size at macroscopic evaluation) per procedure was processed for histopathology (range 9-24) and dedicated to the study. At the histopathologic evaluation, a gradable tissue (visible lining layer and ≥ 4 fragments with IST) was recognized in 19/20 biopsies (95%), and all pre-defined histometric parameters were judged applicable and successfully measured in 19/19 gradable biopsies. All three biopsy target sites showed sampling accessibility. The entire procedure was generally well tolerated. At the 1-month follow-up, no patients showed infectious complications.

CONCLUSIONS

The access route through the anatomical snuff box in US-guided synovial biopsies of the RC joint allows for a safe and targeted collection of adequate tissue samples. This modification of the traditional access route may allow easier, repeatable, and safer sampling of anatomically distinct areas of the wrist in the course of arthritis.

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.

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.

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.

Avoiding and treating perioperative complications of distal radius fractures

Numerous methods of treatment are available for the management of distal radius fractures, with modern trends favoring volar fixed-angle distal radius plates. Whatever the method of fixation, recognition, management, and prevention of the known associated complications are essential to achieve a good outcome. This article reviews the common preventable complications that are associated with operative treatment of distal radius fractures, including tendon injuries, inadequate reduction, subsidence or collapse, intra-articular placement of pegs or screws, nerve injuries, complex regional pain syndrome, carpal tunnel syndrome, and compartment syndrome.

The cadaveric anatomy of the distal radius: implications for the use of volar plates

INTRODUCTION

Fractures of the distal radius are common upper limb injuries, representing a substantial proportion of the trauma workload in orthopaedic units. With ever increasing advancements in implant technology, operative intervention is becoming more frequent. As growing numbers of surgeons are performing operative fixation of distal radial fractures, an accurate understanding of the relevant surgical anatomy is paramount. The flexor carpi radialis (FCR) tendon forms the cornerstone of the Henry approach to the volar cortex of the distal radius. A number of key neurovascular structures around the wrist are potentially at risk during this approach, especially when the FCR is mobilised and placed under retractors.

METHODS

In order to clarify the safe margins of the FCR approach, ten fresh frozen human cadaver limbs were dissected. The location of the radial artery, the median nerve, the palmar cutaneous branch of the median nerve and the superficial branch nerve were measured with respect to the FCR tendon. Measurements were taken on a centre-to-centre basis in the coronal plane at the watershed level. In addition, the distances between the tendons of brachioradialis, abductor pollicis longus and flexor pollicis longus, and the radial artery and median nerve were measured to create a complete picture of the anatomy of the FCR approach to the distal radius.

RESULTS

The structure most at risk was the palmar cutaneous branch of the median nerve. It was located on average 3.4mm from the FCR tendon. The radial artery and the main trunk of the median nerve were located 7.8mm and 8.9mm from the tendon. The superficial branch of the radial nerve was 24.4mm from the FCR tendon and 11.1mm from the brachioradialis tendon.

CONCLUSIONS

Operative intervention is not without complication. We believe a more accurate understanding of the surgical anatomy is key to the prevention of neurovascular damage arising from the surgical management of distal radial fractures.