L-pinning in 5th MC neck fracture accelerates recovery in adolescents without post-op immobilization

Saint Etienne, France: 5th metacarpal neck fracture is the most frequent type of hand fracture in adolescents between 13 and 16 years of age. It mainly affects males and the dominant hand. The L-pinning technique combines intramedullary anterograde pinning and transverse pinning between the 4th and 5th metacarpals.

E. Haddad,M. Zemour, Y. Belkacemi et al. presented a study which aimed to assess L-pinning without postoperative immobilization in displaced 5th metacarpal fracture in adolescents with low residual growth.

Data for patients aged between 13 and 16 years, operated on for closed 5th metacarpal neck fractures were analyzed retrospectively. Surgery was indicated for angulation with > 30◦ palmar tilt and/or horizontal malalignment.

Surgical technique:

Surgery was performed by a senior surgeon, under general and locoregional anesthesia and fluoroscopic control, without tourniquet.

Step 1: Fracture reduction by Jahss maneuver, then 1 cm skin incision on the dorso-ulnar edge of the base of the 5th MC. Retraction of extensor tendon and ulnar nerve sensory branch. Bone trepanation distal to carpometacarpal joint and introduction of antegrade intramedullary pre-curved 20/10th K-wire up to the fracture line. Dorsal rotation of the pin is then necessary to reduce the palmar tilt before pushing the pin distally up to the subchondral bone. Clinical rotational disorder can then be corrected manually if needed.

Step 2: Under fluoroscopic control, by the ulnar edge of the head of the 5th MC, an 18/10th K-wire is inserted with a slow power drill parallel to but away from the growth plate and the joint surfaces bridging the 4th and 5th MC heads; the K-wire blocks the horizontal axis within the fracture site. The 2 K-wires are then cut, slightly bent and buried beneath the skin. A simple dressing is used postoperatively, without rigid immobilization.

Hardware was removed as of day 28.

The final clinical check-up was at ≥ 12 months.

Results:

• Eighteen patients, all male, with a mean age of 14 years, were included.

• All had bone age ≥ 14 years.

• Mean palmar tilt was 52◦ ± 6.8◦ versus 6◦ ± 2.4◦ postoperatively, for a mean correction of 45◦ ± 4.3◦.

• Mean operating time was 15 min, and X-ray exposure 0.36 minutes for a mean radiation dose of 2.89 cGy/cm2.

• At hardware removal, all patients showed radiologic consolidation.

• At 3 months, 5th ray ranges of motion were normal, with no local complications.

• Functional results were maintained at last follow-up (≥ 12 months).

• On the Frère et al. criteria, 17 patients had "excellent" results with normal hand function, and only one had pain on effort("good" result).

The authors concluded that, L-pinning seemed reliable in terms of feasibility and stability of reduction in 5th metacarpal neck fracture in adolescents. Absence of postoperative immobilization facilitated self-rehabilitation and accelerated functional recovery.

Key Words: Fifth metacarpal neck fracture, L-pinning, Hand fracture, Adolescent fracture, Minimally invasive surgery.

Further reading:

L-pinning for fifth metacarpal neck fracture in adolescents

Level of evidence: IV

Elie Haddada, Marion Zemour, Yacine Belkacemi, Hassan Al Khoury Salema, Bruno Dohina,

Orthopaedics & Traumatology: Surgery & Research 108 (2022)102992

https://doi.org/10.1016/j.otsr.2021.102992