A proposed radiological classification system of Hoffa’s fracture based on fracture configuration and consequent optimal treatment strategy along with the review of literature

Background: Coronal fractures of distal end femur, referred as Hoffa’s fracture are not uncommon, yet easily missed injuries lacking proper classification system and consensus for ideal treatment. While most trauma surgeons adopt different strategies based on the fracture configuration and their own experience, there are no set ways to classify these based on the most appropriate treatment strategy. Methods: Thirty cases of Hoffa fracture from tertiary care centres were studied for the fracture pattern, fragment size, comminution and possible variations to formulate a radiological classification and treatment guidelines. Additionally, a literature search was used to analyze 77 case studies based on Hoffa fracture to find out the common fracture patterns and treatment modalities adopted for varying fracture patterns in these studies. Six independent observers participated in testing the inter-observer reliability of the proposed classification. Results: A new proposed radiological classification for Hoffa fracture consists of four main types. Type 1 is with fracture fragment >2.5 cm, Type 2 with fragment <2.5 cm, Type 3 is comminuted fracture, Type 4 are subdivided as Type 4a – Anterior, Type 4b – Bicondylar, Type 4c – Osteochondral type and Type 4d – With supracondylar extension. Optimum treatment modality depends on the type of Hoffa’s fracture and has been suggested in the study. Interobserver reliability demonstrated that overall agreement was 0.907692 with a fixed marginal Kappa of 0.881067 and free Marginal Kappa at 0.892308. Intra-observer reliability test for the classification system showed a strong Kappa value of +1.0. Conclusion: The new suggested classification helps identify different types of Hoffa’s fracture. This is likely to help decide optimal surgical treatment depending on the nature of the injury. The classification system has high inter and intra-observer reliability that enables its universal applicability.