gms | German Medical Science

Clinical issue/s: The Thomine protocol and later on the Lucerne cast (LuCa) introduced the fixed MCP-joint flexed position as the principal stabilizer in sufficiently-aligned proximal phalanx fractures. The biomechanical advantage of the splint design is based on the Zancolli complex which is stretched during MCP-joint flexion thereby keeping the fracture fragments in the right position. The LuCa allows for some use of the hand and preserves the mobility of all the finger joints.

Clinical reasoning: While a regular follow-up is strongly recommended in the conservative treatment of hand fractures, a secondary fracture dislocation rarely happens. Most so-called secondary dislocations result more likely from a slightly changed x-ray projection than from a repositioning of fracture fragments.

Functional fracture treatment should therefore be in most fractures allowed from the beginning and result in good functional results concerning finger motion and dexterity.

What are the basic problems preventing the theoretically expected results?

There are two principal problems. First: The concern of the patient to harm his hand restrains him to use it at all. Secondly: The spontaneous intrinsic minus position of an injured hand results in early joint stiffness.

Innovative, analytical or new approach: Considering both basic problems of functional hand fracture treatment, we remembered the advantages of the LuCa:

The LuCa provides physical and, perhaps more important, psychological protection of the fracture site and prevents the unwanted intrinsic minus position at the same time.

Meanwhile, we are treating most of our metacarpal and finger fractures by applying a LuCa, often combining it with buddy-taping of neighbored finger-rays. Motion and load are completely left to the patient's convenience and are never restricted formally.

Contribution to advancing HT practice: In our hands, the LuCa is not only an instrument to prevent dislocation of proximal phalanx finger fractures. It represents a paradigm shift in helping the patient to treat functionally and intuitively fractures elsewhere in the hand.