Functional results and isokinetic muscle strength in patients with Fraser type I floating knee treated with internal fixation

Abstract

Introduction: According to Fraser's description, ipsilateral femoral and tibial diaphyseal fractures are characterised as type I floating knee and have a better prognosis than fractures with joint involvement (type II). There are few reports of functional and muscle strength in these patients. The objective of this study was to evaluate the functional and isokinetic muscle strength of patients with type I floating knee undergoing femoral and tibial internal fixation.

Methods: Patients with type I floating knee undergoing concomitant femoral and tibial internal fixation were invited for clinical evaluation. The parameters evaluated included the following: Karlstrom and Olerud score; Lysholm score; isokinetic thigh and hip muscle evaluation; knee range of motion; pain level; investigation of associated knee injuries by clinical evaluation and MRI; and types of complications.

Results: Twenty-one patients were included in the study; 11 of these were clinically evaluated, with a mean follow-up of 23.9 months. Six patients had an acceptable result according to the Karlstrom criteria, whereas eight patients had a poor result based on the Lysholm scale. The peak torque deficit was 61% for knee extensors, 37% for flexors and -9% for hip abductors. The mean pain level was 5.9. Three patients had a partial anterior cruciate ligament (ACL) injury; one patient had a posterior cruciate ligament (PCL) injury; and three patients had a meniscal injury. There were four cases of tibial or femoral nonunion at one year and two cases of chronic osteomyelitis.

Conclusion: Patients with type I floating knee had unsatisfactory functional results, significant knee extensor and flexor muscle strength deficits and a significant rate of complications at the two-year follow-up.

Keywords: Femoral fracture; Internal fixation; Ipsilateral fracture; Isokinetic muscle strength; Tibial fracture; Type I floating knee.