Session IV - Pediatrics

The Pediatric Floating Knee: Results of Closed versus Rigid Stabilization

James J. Yue, MD, R. Sean Churchill, MD, Daniel R. Cooperman, MD, John H. Wilber, MD, George H. Thompson, MD, and Alan Yasko, MD

MetroHealth Medical Center/University Hospitals of Cleveland, Cleveland, Ohio, USA

Purpose: The purpose of the present study was to evaluate the use of traction and delayed casting versus rigid stabilization of ipsilateral femur and tibia fractures in children and adolescents.

Methods: Between 1975 and 1996, 33 patients with ipsilateral fractures of the femur and tibia with open epiphyseal growth plates were treated at our institution. Of these 33 patients, 2 patients were lost to follow-up prior to one year and 2 patients died shortly after their admissions, leaving 29 patients with 30 extremities for final analysis. A retrospective chart review was performed on all patients. In addition, 25 patients (86%) were available for functional assessment telephone interviews and/or physical examination. All parameters (i.e., age, complication rates, corrective surgery rates, and time to unsupported ambulation) were determined for fractures treated with traction and casting (closed treatment) and for those fractures treated with rigid stabilization (external fixators, intra-medullary rods and ORIF). Scanograms were used to evaluate leg length discrepancies. A Student's t-test or z-test of ratios assuming both equal and unequal variances was performed for statistical analysis as indicated.

Results: The median age of all patients was 8.7 years (range 2-16). The median age was 8.8 years for those patients treated with traction and casting and 8.5 years for those treated with rigid stabilization (p>0.43). There were 22 males and 7 females. Twenty-four open fractures of either the tibia and/or femur were sustained. The median injury severity score was 17. Four amputations were performed as a result of Grade III open injuries. Rigid stabilization using intra-medullary rods, external fixators, or ORIF was used to treat nine femur fractures and 13 tibia fractures in a total of 13 patients. Traction and casting alone was performed in 16 patients.

Complications occurred in 15 patients: 5 fracture malunions, 1 premature physeal closures, 1 tibial non-union, 3 pin tract infections, and 10 leg length discrepancies. Six patients required additional surgery for malunion and shortening osteotomy (1), bone grafting for non-union (1), arthroscopy for intra-articular lysis of knee adhesion (1), epiphyseodesis (1), hardware failure (1) and painful hardware (1).

Follow-up was obtained for an average of 9 years (5.5 years for rigid stabilization and 12.6 years for traction and casting). One patient treated with traction and casting required epiphyseodesis of the ipsilateral extremity whereas none of the patients treated with rigid stabilization required this procedure (p>0.05). Five patients treated with traction also complained of rotational or angular deformities. All patients had full hip, knee, and ankle range of motion. Five patients (17.2%) demonstrated anterior knee instability suggesting cruciate ligament deficiency. Unassisted weight bearing occurred at an average of 5.2 months in those patients treated with casting, and at an average of 3.9 months for those treated with rigid stabilization (p<0.05). Scanograms demonstrated leg length discrepancy in 10 patients who had an overgrowth greater than 2 centimeters (3 rigid and 7 closed; p>0.05).

Discussion: Previous studies (Bohn and Durbin, JBJS 73A, 429-439; Letts and Vincent, JBJS 68B, 442-446) have attempted to examine the relationship between age and treatment in the pediatric floating knee. However, to the best of our knowledge, a study which has had equal age groups in both a traction group as well as a rigid stabilization group has not been performed.

Conclusions: 1. Our results support the hypothesis that rigid stabilization of at least one of the long bone fractures in the pediatric floating knee will result in excellent clinical outcomes in both the child and the adolescent. 2. Although good to excellent results can be obtained with traction and delayed casting, rigid stabilization in the child is an effective method of treatment and may help to preclude the need for delayed epiphyseodesis as well as osteotomy for rotational and angular deformities. 3. Associated ligamentous injuries of the knee occur in a high percentage of pediatric floating knees.