Posterior interosseous nerve localization within the proximal forearm - a patient normalized parameter

Estimating the location of the posterior interosseus nerve during an extensor digitorum communis-splitting approach: a comparison of methods using the transepicondylar distance

Background

The posterior interosseus nerve (PIN) may be encountered when using the extensile extensor digitorum communis (EDC)-splitting approach to the elbow. An accurate means of estimating its location remains elusive. The purpose of this investigation is to identify whether the methods described in previous studies can be improved upon to more accurately estimate the PIN's location using the transepicondylar distance (TED).

Methods

Forty-five fresh-frozen cadavers were dissected using the EDC-splitting approach. Method A (N = 39) used an electronic caliper measuring along the midlateral border of the radius from the lateral epicondyle (LE) and radiocapitellar joint in supination, neutral position, and pronation. Method B (N = 16) used a sterile tape measure, measuring from the LE in pronation only along an axis from the LE to Lister's tubercle passing through the center capitellum.

Results

In method A, the mean TED was 63.4 ± 6.1 mm. Of the 6 measurements, the TED was most correlated to the actual distance to the PIN from the LE in pronation (68.3 ± 7.3 mm; R² = 0.266). The median difference between the estimated and actual distances was -5.6 mm (-19.3 mm to 7.6 mm). In method B, the mean TED was 68.4 ± 8.7 mm, and the mean measured distance from the LE in pronation was 68.7 ± 9.4 mm. The TED closely correlated with the measured distance to the PIN (R² = 0.95, P < .001). The mean difference between the estimated and actual distances was ±2.0 mm (range -4.0 mm to 2.0 mm), significantly more precise than method A (P = .007).

Conclusion

Using a tape measure, the TED predicted the PIN's location within a mean ±2 mm in pronation along an axis from the LE to Lister's tubercle, using an EDC-splitting approach. This technique is simple and comparatively more accurate than those used previously.

Antegrade elastic stable intramedullary nail fixation for paediatric distal radius diaphyseal metaphyseal junction fractures: A new operative approach

BACKGROUND AND PURPOSE

The treatment of paediatric distal radius diaphyseal metaphyseal junction (DRDMJ) fractures is a challenge. The purpose of this study was to introduce a new operative approach at the proximal "safe zone" of the posterior interosseous nerve (PIN) to treat paediatric DRDMJ fractures and analyse the safety and efficacy of antegrade elastic stable intramedullary nail (ESIN) fixation.

METHODS

Thirty paediatric patients with unstable and displaced DRDMJ fractures were treated by antegrade ESIN fixation from November 2015 to September 2017. We created the entrance site at the posterolateral side of the proximal radius and 2˜4 cm distal to the articular surface of the radius, using the ESIN to immobilise the fractures. In the study, we reviewed patient demographics, complications, time until removal, and intraoperative time for hardware removal.

RESULTS

Complete fracture healing was achieved between 6 and 12 weeks after surgery. Except for 3 patients presenting with irritation of the skin, we did not observe any complications. Radiologically, no secondary displacement, nail migration, loss of fixation, consolidation delay, non-union, or refracture was noted.

CONCLUSIONS

The antegrade ESIN fixation is a minimally invasive, easy-to-learn, alternative operative method to treat paediatric DRDMJ fractures.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Classification of the transverse pattern of Mason II radial head fractures and its usefulness in arthroscopic osteosynthesis. Anatomo-surgical study

OBJECTIVE

The management of MasonII fracture pattern assisted by arthroscopy is a valid technique that provides good results. The objective of this study was to draw attention to the usefulness of the location of the fracture in the head of the radius in defined quadrants with respect to the bicipital tuberosity through CT. This would help to plan the optimal forearm position to access each quadrant and foresee the specific difficulties of each one.

MATERIAL AND METHOD

We dissected 4 specimens of cryopreserved cadaver. We divided the radial head into 4 quadrants with regard to the bicipital tuberosity, objectifying the change of position in pronation and maximum supination with respect to the sigmoid cavity and neurovascular structures.

RESULTS

The head of the radio moves with pronosupination, so there are areas of convergence between the different quadrants. Quadrant1 is approached in supination via an anteromedial portal. Quadrant2 is approached in maximum pronation through a lateral portal. Quadrant3 can be approached through lateral portals, with the forearm in neutral position and in pronation. Quadrant4 is accessible with the forearm in a neutral position and in supination through a lateral portal.

CONCLUSIONS

Depending on the location of the fracture in the head of the radius with respect to the bicipital tuberosity, we will need access through a specific arthroscopic portal, with the medial quadrants (anteromedial and posteromedial) being the most technically demanding.