- Radiographic Alignment (see: malunion of tibial frx)
- acceptable reduction:
- as noted by Milner SA (1997), there is a considerable amount of tibial shaft alignment variety, and therefore,
when there is a question of whether the reduction is acceptable, x-rays of the opposite leg should be obtained;
- this author noted that the mechanical axis of the normal tibia may not pass down the center of the medullary canal;
- ref: A more accurate method of measurement of angulation after fractures of the tibia..
- classic parameters:
- more than 50% of cortical contact;
- less than 5-10 deg of varus / valgus angulation when comparing tibial plateau to tibial plafond (some will not accept more than 5 deg of varus);
- less than 10-15 deg of anterior or posterior bowing on lateral film;
- less than 5 - 7 deg of internal or external rotation, varus or valgus;
- no more than 10-15 mm of shortening;
- Casting Technique:
- initial long leg cast be applied w/ knee in 0 to 5 deg flexion (more flexion will allow better rotation control of the fracture);
- note: application of well molded cast can dramatically increase compartment pressures;
- location for casting:
- office -- if the fracture does not need reduction in the patient can sit with the knee flexed to 90° over the table.
- emergency room --is sedation is needed and reduction can be obtained with minimal manipulation
- operating room -- if more sedation is needed or more manipulation is needed
- procedure for casting with minimal sedation
- patient is supported while sitting with the knee flexed 90° over the end of the table;
- gravity will often reduce the fracture;
- an assistant places his hands under the metatarsal heads to keep the ankle at 90° in neutral or slightly protonated position.
- surgeon may have to manipulate the fracture;
- well padded short leg cast is applied holding the fracture reduction;
- after the cast has partially dried, add soft roll and plaster to make it a long leg cast with the knee infive to 10° flexion;
- if the fracture is distal, the PTB cast with molding around the tibia condyles can be applied;
- be sure the bottom of the cast is molded to accommodate the walker;
- patient can use crutches and bear weight as tolerated;
- fracture is x-rayed weekly for two weeks, and then at six weeks postinjury.
- casting is done the same in hospital;
- position of ankle:
- w/ a recurvatum deformity, the foot should be placed in slight plantar-flexion;
- neutral dorsiflexion will increase frx recurvatum in an unstable frx;
- if fascial compartments are somewhat tight (but compartment syndrome is not present) consider placing ankle in slight flexion (between the resting and neutral position) as well as bivalving the cast;
- after 3-5 weeks, switch to short leg cast or a cast brace;
- there are some frx that are best left in above knee cast, such as frxs close to knee joint, and frx assoc w/ intact fibula;
- always consider the risk of DVT (especially in obese patients);
- DVT prophylaxis for frx trauma;
- Wt Bearing:
- there is a correlation between delayed wt bearing & delayed or non union;
- w/ stable frx, wt bearing is begun as soon as tolerated;
- usually between 7th and 14th day, pt achieves full wt bearing w/ crutches;
- weekly x-rays are required to confirm adequacy of reduction, then as callus forms, radiographs are taken every 2 to 3 weeks;
- when fully wt bearing, the pt may switch to canes as tolerated;
- w/ stable frx, above knee cast may be converted to below knee patellar bearing cast at 3-5 weeks;
- there are some frx that are best left in above knee cast, such as fractures close to knee joint, and frx assoc w/ intact fibula;
- cast modification:
- once partial fracture healing has taken place, consider functional brace or consider a below knee cast w/ dorsum of foot and ankle removed to allow ankle dorsiflexion;
- active dorsiflexion and plantarflexion stresses the tibia and produces displacements similar to wt bearing;
- Tibial Non Unions:
- ideally wt. bearing is begun no later than 6 weeks after injury;
- if delayed union is suspected in pt who has been non-wt bearing for 3-4 mo, wt bearing should be instituted, preferably in long leg cast;
- if fibula is intact or has healed, resection of 1-2 cm of fibula may improve loading of frx site & stimulate union;
- this will result in union of fairly high % of delayed unions;
- Outcome Studies:
- Sarmiento A (1967)
- Rx: w/ a patella tendon bearing cast
- 100 consecutive fractures managed by reduction and long leg cast immobilization for 2 to 4 weeks, then application of the PTB cast;
- all fractures united, with closed fractures uniting in an average of 13.6 weeks and open fractures in an average of 16.7 weeks;
- shortest time to union was 9 weeks with a type A fracture;
- longest time to union was 21 weeks with a type C fracture;
- shortening averages 7 mm w/ a maximum shortening of 2.2 cm;
- Sarmiento A, et al. (1989)
- 780 selected fractures treated w/ early wt bearing and PTB bracing;
- 97.5% union rate;
- 90% of patients had less than 1 cm of shortening;
- 2% of patients had varus or valgus angulation > 11 deg;
- 2% of patients had anterior or posterior angulation > 10 deg;
- 4% of patients needed to have bracing discontinued, loss of position
- best results in closed and low energy fractures;
- Casting Pearls:
- be sure to mold under the sole of the foot inorder to restore the normal arch;
- the plantar aspect of the cast should come up the MTP flexion crease;
References: A functional below-the-knee cast for tibial fractures.
Tibial shaft fractures treated with functional braces. Experience with 780 fractures.
The healing of closed tibial shaft fractures. The natural history of union with closed treatment.
Factors influencing the outcome of closed tibial fractures treated with functional bracing.
Effects of tibial malalignment on the knee and ankle.
No arthrosis of the ankle 20 years after malaligned tibial-shaft fracture.
Cast brace treatment of proximal tibia fractures. A ten-year follow-up study.
Tibial fracture stability. Analysis of external fracture immobilization in anatomic specimens in casts and braces.
Control of motion of tibial fractures with use of a functional brace or an external fixator. A study of cadavera with use of a magnetic motion sensor.
Conservative management or closed nailing for tibial shaft fractures. A randomised prospective trial.
Setting temperatures of synthetic casts.
Tibial cast wedging: a simple and effective technique.
Effect of Ankle Position and a Plaster Cast on Intramuscular Pressure in the Human Leg.
Displaced isolated fractures of the tibial shaft treated with either a cast or intramedullary nailing. An outcome analysis of matched pairs of patients..
Thermal Injury with Contemporary Cast-Application Techniques and Methods to Circumvent Morbidity
In Brief: Closed Tibial Shaft Fractures