Femoral-shaft fracture — the Thomas splint and evolving compartment syndrome

(a) The governing principle and the device choice (3 marks).

• The governing principle of splinting is that the device immobilises the joint above and the joint below the fracture — for a femoral-shaft fracture the splint must control the hip and the knee and align the fragment by traction.
• Device — the Thomas splint with a fixed or balanced traction setup. Rationale: it is the standard for the femoral-shaft fracture because the padded ring seats against the ischial tuberosity, the ankle hitch applies longitudinal traction, and the alignment of the fragments relieves the muscle spasm, which markedly reduces pain, blood loss and further soft-tissue injury. A simple splint cannot control a femoral shaft — the powerful thigh muscles angulate the fragment and the patient remains in severe pain.
• Pain and blood loss. Traction relieves pain more than a simple splint at 1, 6 and 12 hours after application; realigning the fragments also limits ongoing soft-tissue injury and bleeding into the thigh compartment.^[3]

(b) Thomas splint application, step by step, and the post-application checks (6 marks).

1. Select the size. Choose a Thomas splint whose ring passes comfortably over the flexed knee and seats in the groin against the ischial tuberosity — too small a ring constricts, too large does not anchor.
2. Prepare the ankle hitch. Apply a padded strap or a commercially designed boot to the lower leg and ankle as the traction point; pad the malleoli.
3. Position the leg. With an assistant supporting the injured leg, gently apply in-line longitudinal traction to align the fracture and pass the ring up the leg to the groin.
4. Seat the ring. Push the ring firmly into the groin so it abuts the ischial tuberosity — this is the proximal anchor against which the traction pulls.
5. Apply traction. Secure the ankle hitch to the distal end of the side-iron with the traction cord; apply longitudinal traction sufficient to align the limb and relieve pain. The traction is balanced against the ring seat.
6. Support the limb. Pad the side-iron along its length and support the leg in a neutral position; the knee is slightly flexed.
7. Post-application checks. Re-check the neurovascular status of the foot — the dorsalis pedis and posterior tibial pulses, capillary refill, and sensation (the peroneal nerve at the fibular head and the sciatic distribution). The ring can compress the peroneal nerve or the sciatic nerve, and the ankle hitch can compromise the foot, so a documented before-and-after neurovascular check is mandatory. Confirm pain relief. Check the ring fit (no perineal or sciatic pressure). Arrange analgesia, the trauma series, orthopaedic referral and admission.^[2]

^[1](c) Evolving compartment syndrome — assessment and management (6 marks).

• Recognise the diagnosis. The combination of severe pain out of proportion and pain on passive stretch (screaming when the toes are moved) in a high-energy lower-limb fracture in a young man is the classic earliest presentation of compartment syndrome — present while the pulse is still palpable. The thigh is tense. McQueen's data identify the high-energy tibial and femoral fracture in the young male as the highest-risk profile; do not be reassured by a present pulse.^[1]
• Immediate action — split the splint to skin. Release the traction and remove the Thomas splint entirely (the ring and the traction are the compressive device here). If a cast were present you would split it to skin (down to and including the wool) and spread it — cutting and spreading the cast with the padding substantially reduces the compartment pressure; for the Thomas splint, release and remove the device. Keep the limb at heart level (do not elevate — elevation drops the perfusion pressure).^[5]
• Reassess. Re-examine the limb — tense compartments, pain on passive stretch of the thigh, sensory changes in the saphenous or peroneal distribution, and the distal pulses (which may still be present). Note that pulselessness is a late, pre-terminal sign; its absence is not required for the diagnosis.
• Analgesia. Give adequate intravenous opioid analgesia; do not let the pain control give false reassurance — continue to investigate.
• Call orthopaedics urgently. Compartment syndrome is a clinical diagnosis confirmed by compartment-pressure measurement and treated by emergency fasciotomy. State explicitly that you would not wait for pressure measurement if the clinical picture is convincing — the fasciotomy is time-critical, and irreversible muscle necrosis begins within hours.
• Document and communicate. Document the neurovascular findings and the time, the removal of the splint, and the orthopaedic referral with the named surgeon and time. Maintain the limb alignment by gentle in-line traction during transfer to theatre.^[2]