This is a randomised, bi-centre, prospective, clinical trial in patients with closed tibia shaft fractures. The fracture should be fresh/acute and seen within 3 weeks after the injury. Patients will be randomised to surgery with either a Taylor Spatial Frame (Smith & Nephew, England) or a reamed intramedullar nail (according to local choice) with locking screws. Primary outcome measure is the physical component summary (PCS) of RAND Short form 36 (SF-36) after 2 years. Among secondary outcomes: Visual Analogue Scale (VAS) for pain, complications, healing, malunion, and resource use.

Fractures of the lower leg (fractures of the tibia shaft with or without concurrent fracture of the fibula) are a common injury. According to our fracture register 95 patients with closed tibia fractures were operated the last 3 years at our department. Fractures with moderate or no displacement can be successfully treated with a cast and subsequent Sarmiento brace. Displaced fractures are commonly treated with an intramedullary nail. Intramedullary nailing yields a high rate of union. More than 50 % of operated patients do, however, develop chronic anterior knee pain and one third of the patients have pain at rest. This contributes a big problem for many patients both at spare time and at work. Another problem is significant rates of malunion.

The use of ring fixators utilizing rings and 1,8 mm. wires was introduced by Gavril Ilizarov more than 50 years ago, and the technique has been further developed through the introduction of six adjustable struts (Taylor Spatial Frame). This hexapod circular frame allows accurate reduction as well as a high stability. The ring fixator is less invasive and allows early weight bearing, but may be cumbersome to the patient. There is also concern about pin-tract infection, osteomyelitis and joint contracture.

Only one prior study has compared ring fixator (Ilizarov) and intramedullar nail in closed tibia fractures. The results showed significant less anterior knee pain in the patients operated with ring fixator, but the study design did not allow clear conclusion.

Inclusion Criteria:

• Closed tibia shaft fractures suited for both study treatments.
• A patient who is informed of the purpose of the investigation and who has given informed consent and willingness to accept randomisation either to Taylor Spatial Frame or intramedullary nailing.
• Willingness and ability to comply with all investigation procedures
• Age between 18 to 70 years
• Skeletally mature
• Previous unaided walking

Exclusion Criteria:

• Participation in other clinical investigations that will interfere with this study
• Mental illness or other conditions that preclude ring fixator in the judgment of the investigator
• Any other concurrent condition(s) that, in the judgment of the investigator, would prohibit the patient from participation in the study
• No other injury or previous disease that would be likely to seriously influence the long term outcome (this will exclude e.g. osteomyelitis, vascular or neurological disorder of the lower extremities, rheumatoid artist, malignancy that could influence on bone healing)
• Compartment syndrome before randomisation
• Pathologic fracture
• Ongoing or previous use the last year of drugs that can be bone anabolic (e.g. anabolic steroids, growth hormone, parathyroid hormone)

Depending on demand. No plan as of yet.

The researcher doing the statistical analyses will be masked for treatment Group (i.e. Group 1 or 2) in a databse blinded for treatment grioups and without variables indirectly revealing treatmnet arm. These will be analyzed later.