Calm, irritated or infected? The experience of the inflammatory states and symptoms of pin site infection and irritation during external fixation: a grounded theory study

The PINS Trial: a prospective randomized clinical trial comparing a traditional versus an emollient skincare regimen for the care of pin-sites in patients with circular frames

AIMS

Pin-site infection remains a significant problem for patients treated by external fixation. A randomized trial was undertaken to compare the weekly use of alcoholic chlorhexidine (CHX) for pin-site care with an emollient skin preparation in patients with a tibial fracture treated with a circular frame.

METHODS

Patients were randomized to use either 0.5% CHX or Dermol (DML) 500 emollient pin-site care. A skin biopsy was taken from the tibia during surgery to measure the dermal and epidermal thickness and capillary, macrophage, and T-cell counts per high-powered field. The pH and hydration of the skin were measured preoperatively, at follow-up, and if pin-site infection occurred. Pin-site infection was defined using a validated clinical system.

RESULTS

Out of 116 patients who were enrolled in the study, 23 patients (40%) in the CHX group and 26 (44%) in the DML group had at least one bad or ugly pin-site infection. This difference was not statistically significant (p = 0.71). There was no significant relationship between pH or hydration of the skin and pin-site infection. The epidermal thickness was found to be significantly greater in patients who had a pin-site infection compared with those who did not (p = 0.01). Skin irritation requiring a change of treatment occurred in four patients (7%) using CHX, and none using DML.

CONCLUSION

We found no significant difference in the incidence of pin-site infection between the CHX and DML treatment groups. Dermol appeared to offer a small but significant advantage in terms of tolerability. We did not find a significant association between patient or treatment related factors and pin-site infection. It is therefore difficult to make specific recommendations based upon these results. The use of either cleaning agent appears to be appropriate. Cite this article: Bone Joint J 2021;103-B(2):279-285.

Patient-reported symptoms of 'calm', 'irritated' and 'infected' skeletal external fixator pin site wound states; a cross-sectional study

OBJECTIVE

To explore the frequency, severity and variances in patient-reported symptoms of calm, irritated and infected skeletal pin sites.

METHODS

A cross-sectional within-subjects repeated-measures study was conducted, employing a self-report questionnaire. Patients (n = 165) treated with lower limb external fixators at 7 English hospitals completed a designed questionnaire. Three sets of retrospective repeated-measures data were collected relating to calm, irritated and infected pin sites.

RESULTS

Significant differences were revealed between each of the three pin site states (calm, irritated & infected) in the degree of: redness, swelling, itchiness, pain, wound discharge, heat/burning, shiny skin and odour. In relation to difficulty or pain using the affected arm or leg, difficulty weight bearing on the leg, nausea and/or vomiting, feeling unwell or feverish, shivering, tiredness/lethargy and disturbed sleep, significant differences were demonstrated between infected and irritated states and infected and calm states, but not between irritated and calm.

CONCLUSIONS

The findings provide greater depth of understanding of the symptoms of pin site infection and irritation. Patients may be able to differentiate between different pin site states by comparing the magnitude of the inflammatory symptoms and the presence of other specific symptoms that relate solely to infection and no other clinical state. The irritated state is probably caused by a different pathological processother than infection and may be an indication of contact dermatitis.

Prevention of infection in external fixator pin sites

Infection in external fixator pins is known to be a significant problem, with incidences between 3% and 80% reported in the literature. An infection occurs when planktonic bacteria adhere to external fixator pins and subsequently produce a biofilm which protects the bacteria from host defences. The most commonly implicated organisms are Staphylococcus aureus and Staphylococcus epidermidis. Once an infection occurs, treatment is difficult. Systemic antibiotics have limited benefits and considerable side-effects. The only definitive management is removal of the pin. This review will consider the current and potential future strategies for reducing pin site infection. Techniques to prevent infection must prevent bacterial adhesion, allow good osteointegration and have a low toxicity. Current areas of interest reviewed are titanium-copper alloys, nanosilver coatings, nitric oxide coatings, chitosan coatings, chlorhexidine and iodine, hydroxyapatite and antibiotic coatings. At present there is no consensus on the prevention of pin site infection, and there is a paucity of randomized controlled trials on which to draw a conclusion. Whilst a number of these strategies have potential future use, many of the above strategies need further studies in animal models to ensure no cytotoxicity and prevention of osteointegration. Following this, well-designed randomized controlled clinical trials are required to give future ways to prevent external fixator pin site infections.