Introduction: High-energy fractures that involve the joint surface of the distal femur are challenging injuries. Less invasive stabilization system (LISS) has been the preferred treatment for these fractures. However few studies has investigated young patients suffering from high-energy trauma with complex articular fractures, AO 33C.
Method: Ten patients with 11 AO 33C fractures, between the age of 18 and 65 years, where identified from a local database at OUS Ullevål. They where clinically, radiologically and functionally evaluated.
Results: The mean age was 42 (32-61) years old. The follow up time was 8-47 months. All fractures were caused by high-energy trauma and treated with the LISS plate. Seven knees underwent secondary surgery, 6 within the follow-up time. Reoperations were due to: Two mal-union, two delayed/non-union, one implant failure and one implant removal due to pain. Clinically they showed an average flexion arc of 95 degrees, limp shortening ranging from 5 to 30 mm and the mean performance on the 6-minute walk test was 414m. Radiologically 6 knees had osteoarthritis, scored with Kellgren–Lawrence grade 2 or worse, no patients show loss of reduction. Functionally only 2 patients were back to work, SF-36 showed a marked reduction in all subscales, most prominently in Role-physical and Physical function. In the KOOS questionnaire our patient group reports considerable difficulties in all five subscales. According to the Schatzker-Lambert classification six of the eleven knees were a failure, three were fair, two were good and none were excellent.
Discussion/conclusion: In our material there was a high incidence of reoperations due to delayed/non–union and mal-union. Health-related quality of life was significantly reduced. The number of patients in this study was small, but all had sustained high-energy injuries and underwent a thorough clinical and radiological examination, in addition to answering validated questionnaires addressing functional outcome and quality of life.
The literature has shown a tendency towards fewer complications like mal/non-union, infections and implant-failure using the LISS-plate. However the evidence base is weak. Our study shows a poorer outcome in this patient group with a higher-incidence of delayed/non-union, mal-unions, a poorer functional outcome and significant self-reported problems. This suggests that the use of LISS in this setting might not give as good results as used on the less “complicated” fractures.