Our aim was to ascertain if K-wire configuration had any influence on the infection and complication rate for base of 4th and 5th metacarpal fractures. We hypothesised that in individuals whose wires crossed the 4th and 5th carpometacarpal joint (CMCJ), the rate of complications and infection would be higher.

Data was retrospectively analysed from a single centre. 106 consecutive patients with a base of 5th (with or without an associated 4th metacarpal fracture) were analysed between October 2016 and May 2021. Patients were split into two groups for comparison; those who did not have K-wires crossing the CMCJ's and those in whose fixation had wires crossing the joints. Confounding factors were accounted for and Statistical analysis was performed using SPSS version 20 software.

Of 106 patients, 60 (56.6%) patients did have K-wires crossing the CMCJ. Wire size ranged from 1.2-2.0 with 65 individuals (65.7%) having size 1.6 wires inserted. The majority of patients, 66 (62.9%) underwent fixation with two wires (range 1-4). The majority of infected cases (88.9%) were in patients who had k-wires crossing the CMCJ, this trended towards clinical significance (p=0.09). Infection was associated with delay to theatre (p=0.002) and longer operative time (p=0.002).

In patients with a base of 4th and 5th metacarpal fractures, we have demonstrated an increased risk of post-operative infection with a K-wire configuration that crosses the CMCJ. Biomechanical studies would be of use in determining the exact amount of movement across the CMCJ, with the different K-wire configuration in common use, and this will be part of a follow-up study.

Pyomyositis is a primary pyogenic infection in skeletal muscle, often progressing to abscess formation. It is rare in temperate climates and generally deep-seated within the pelvis with non-specific clinical features, making diagnosis difficult. Magnetic Resonance Imaging (MRI) is highly sensitive for muscle inflammation and fluid collection and with its increasing availability is now the investigation of choice. Treatment of pyomyositis abscess has traditionally been with incision and drainage or guided aspiration followed by a prolonged course of antibiotics, although there are sporadic reports of cases treated successfully with antibiotics alone. From our 20 year database of over 16000 paediatric orthopaedic admissions we identified only 3 cases with MRI-confirmed pyomyositis abscess. These were all in boys (aged 2-12) and affected the gluteal, piriformis and adductor muscles. Despite the organisms not being identified, each patient was treated successfully with a short (4-7 day) course of intravenous antibiotics followed by 2-6 weeks of oral therapy. There were no recurrences or complications and all made a full recovery. We propose that uncomplicated pyomyositis abscess in children may usually be managed conservatively without the need for open or percutaneous drainage.