- See:
Limb Lengthening Fixators
Post Op Care in the Ilizarov Method: (by
Dr. Mangal Parihar)
distraction histiogenesis
- Discussion:
- lengthening thru the proximal tibia, tends to drift into valgus and procurvatum, and therefore consider presetting distraction in 5 deg of varus;
- lengthening thru the distal tibia tends to drift into varus and procurvatum;
- immediate correction of proximal tibial varus deformities of upto 40 deg can usually be performed safely;
- correction of proximal tibial valgus deformities may risk
peroneal nerve palsy;
- it is unclear whether prophylacitic peroneal nerve decompression will reduce palsy;
- average healing indices for tibial lengthening is 32 days per cm;
- fibular osteotomy:
- fibular shaft must undergo osteotomy inorder to avoid a valgus tibial deformity;
- approximately 1-3 cm of the fibula mid-shaft should be resected to prevent consolidation;
- be aware of the danger zone of fibular osteotomy which lies between 70 mm and 150 mm from the fibular head (which endangers nerve branches to the
EHL);
- some surgeons prefer to osteotomize the fibula at the junction of the distal and middle thirds of the fibula;
- some surgeons will stabilize the distal fibula with an external fixation pin or with a screw placed from the lateral
aspect of the leg (to prevent proximal migration);
- when the tibia is going to be lengthened more than 15%, consider insertion of a syndesmosis screw, inorder to help prevent fibular migration;
- complications:
- equinus deformity:
- may be partially prevented w/ prophylactic PT and bracing (AFO worn at night);
- if more than 25 deg of equinus develops, surgical lengthening may be required;
- w/ significant tibial lengthening, upto 50% of patients may require Achilles tenotomy;
- knee flexion contracture:
- may occur due to tethering effect of hamstrings and gastrocnemius;
- Specific Lengthening Methods:
-
Wagner Method:
- distraction apparatus is applied following a mid-diaphyseal osteotomy;
- following completion of lengthening, the lengthening apparatus is removed, & metal side plate is applied along w/ bone grafting to diaphyseal defect;
-
Ilizarov Technique;
- bone is lengthened at a rate of 1.0 to 1.5 mm per day.
- gradual distraction allows the neurovascular bundle and muscles to lengthen safely;
- osteotomy is performed at lower metaphyseal level for enhanced bone healing;
-
Immediate Lengthening:
- references:
- Limb Lengthening and Correction of Angulation Deformity: Immediate Correction by Using a Unilateral Fixator. J of Pediatric Orthop Vol 16. 1996. p 477-479.
-
One-stage lengthening for femoral shortening with associated deformity.
-
Complications:
- adults will have a much higher complication rate than children;
- avoid simultaneous femoral and tibial lengthenings;
- contractures:
- occur from stretk
- neurovascular damage from stretching;
- if neurological damage develops, then lengthening must be stopped or reversed;
- consider decompression of the peroneal nerve over the fibular neck along with excision of the fascia lata and lateral intermuscular septum;
- fractures:
- lengthening should never be attempted through a previous fracture site;
Lengthening of congenital lower limb deficiencies.
One-stage lengthening for femoral shortening with associated deformity.
The effect of lengthening of the femur on the extensors of the knee. An electromyographic study.
Results of the Wagner and Ilizarov methods of limb-lengthening.
Limb Lengthening and Correction of Angulation Deformity: Immediate Correction by Using a Unilateral Fixator.
M. Kamegaya MD et al. Journal of Pediatric Orthopaedics. Vol 16. 1996. p 477-479.
Distraction osteogenesis of the lower extremity with use of monolateral external fixation. A study of two hundred and sixty one femoral and tibia.
KJ Noonan MD et al. JBJS. Vol 80-A. No 6. Jun 1998.
Bone transport in the management of posttraumatic bone defects in the lower extremity.
Functional Outcome Following Bone Transport Reconstruction of Distal Tibial Defects.
