Implant Site Complications

Infection at the implant site is uncommon and usually mild. Neurovascular injury results from deep insertion or traumatic removal near the medial antebrachial cutaneous, ulnar and median nerves and the brachial vessels. The patient is advised to return for pain, heat, pus or redness at the insertion site, and for a rod that comes out or soreness that develops after the plaster is removed.

Infection presentation. Pain, redness, warmth, swelling, discharge or pus at the site, fever, and sometimes spreading cellulitis or abscess.

Neurovascular presentation. Burning, numbness or tingling in the forearm or hand, weakness of grip, loss of sensation, arm swelling, discolouration, cold hand, or severe pain that does not settle.

History. Date of insertion or removal, aseptic technique, symptoms, diabetes, immunosuppression, HIV status, wound care.

Examination. Site inspection, palpation of rods, temperature, regional lymph nodes, distal neurological and vascular examination including pulses, capillary refill and sensation.

Differential diagnosis. Cellulitis, abscess, haematoma, expelled or protruding rod, allergic reaction to plaster or antiseptic, nerve injury, vascular injury, deep infection, and rod fracture.

Investigations. Swab of any discharge for culture. Full blood count and blood glucose for systemic illness. Ultrasound for abscess, haematoma or deep implant. Nerve conduction studies for persistent deficit.

Indications for removal. Deep infection, abscess, infection not responding to antibiotics, or rod protruding through the skin.

Mild infection or cellulitis. Cefalexin 500 mg orally every 6 hours for 5 to 7 days, maximum 4 g daily. Reduce to 250 mg every 8 to 12 hours when creatinine clearance is 15 to 29 mL/min and 250 mg every 24 hours under 15 mL/min. Alternative: flucloxacillin 500 mg orally every 6 hours for 5 to 7 days, maximum 4 g daily, with caution in liver disease. In penicillin allergy: clindamycin 300 mg orally every 6 hours for 5 to 7 days, maximum 1.8 g daily. All are compatible with breastfeeding.

Suspected resistant staphylococcus. Co-trimoxazole 960 mg orally every 12 hours for 5 to 7 days. Halve the dose in creatinine clearance of 15 to 30 mL/min and avoid under 15 mL/min. Avoid in the first trimester and near term, and in significant liver disease.

Abscess. Incise and drain, culture the pus, and continue antibiotics. Remove the implant if the abscess is deep or recurs.

Rod protrusion or expulsion. Treat any infection first. Remove the implant if needed. Once infection has resolved, insert a new set in the other arm or in the reverse direction in the same arm, or help the patient to choose another method.

Pain control. Paracetamol 1 g every 6 hours, maximum 4 g daily (3 g in liver disease or weight under 50 kg), and ibuprofen 400 mg every 8 hours with food for up to 3 days, maximum 1.2 g daily, avoided in creatinine clearance under 30 mL/min.

Neurovascular injury.

1. Stop any removal attempt.
2. Examine the hand for pulses, perfusion and sensation.
3. Arrange urgent imaging.
4. Refer to a surgeon or specialist centre for removal under imaging control when the implant lies near the nerve or vessel.
5. Do not explore blindly.

Contraceptive cover. Condoms or another method until an alternative is in place.

Follow up. Review at 48 to 72 hours for infection, and again at 1 week. Reassess neurological status at each visit.

Method decisions. After infection has resolved and the site has healed, a new implant may be placed in the other arm. If the patient prefers another method, offer one.

Referral and escalation. Refer deep or recurrent infection, abscess unresponsive to drainage, any neurological deficit or signs of vascular injury, and implants that cannot be located or removed safely.