Nonunion - consensus from the 4th annual meeting of the Danish Orthopaedic Trauma Society

Abstract

Nonunions are a relevant economic burden affecting about 1.9% of all fractures. Rather than specifying a certain time frame, a nonunion is better defined as a fracture that will not heal without further intervention.Successful fracture healing depends on local biology, biomechanics and a variety of systemic factors. All components can principally be decisive and determine the classification of atrophic, oligotrophic or hypertrophic nonunions. Treatment prioritizes mechanics before biology.The degree of motion between fracture parts is the key for healing and is described by strain theory. If the change of length at a given load is > 10%, fibrous tissue and not bone is formed. Therefore, simple fractures require absolute and complex fractures relative stability.The main characteristics of a nonunion are pain while weight bearing, and persistent fracture lines on X-ray.Treatment concepts such as 'mechanobiology' or the 'diamond concept' determine the applied osteosynthesis considering soft tissue, local biology and stability. Fine wire circular external fixation is considered the only form of true biologic fixation due to its ability to eliminate parasitic motions while maintaining load-dependent axial stiffness. Nailing provides intramedullary stability and biology via reaming. Plates are successful when complex fractures turn into simple nonunions demanding absolute stability. Despite available alternatives, autograft is the gold standard for providing osteoinductive and osteoconductive stimuli.The infected nonunion remains a challenge. Bacteria, especially staphylococcus species, have developed mechanisms to survive such as biofilm formation, inactive forms and internalization. Therefore, radical debridement and specific antibiotics are necessary prior to reconstruction. Cite this article: EFORT Open Rev 2020;5:46-57. DOI: 10.1302/2058-5241.5.190037.

Keywords: educative; fracture treatment; nonunion; principals; review; strain theory.

Fig. 1

Intramedullary nail for infected situations. Individually manufactured cement-coated nail loaded with antibiotics.

Fig. 2

Intramedullary nail to treat a nonunion. (a) and (b) show a fracture of the lower leg between the proximal and the middle third. The tibia was initially stabilized using a LISS (less-invasive stabilization system) reconstructing axis, length and rotation but lacking compression and leaving a gap. (c) and (d) show the situation after six months with a persisting fracture line. The patient presented with pain while bearing weight. The inserted nail provided stability, biology after reaming and was used to compress by striking back after distal locking as shown. The proximal dynamic locking option was used. (e) and (f) demonstrate sufficient callus formation and bone bridge after three months, the patient was pain-free.

Fig. 3

Taylor Spatial Frame for correction of malalignment and distraction osteogenesis. (a) and (b) show the clinical situation with varus malalignment of the lower leg and assembled Taylor Spatial Frame. (c) demonstrates sufficient healing and correct alignment after lengthening.

Fig. 4

Plating to treat nonunions. (a) shows an AO-type 32-C3 fracture stabilized with a nail. After six months, the initially complex fracture turned into a simple nonunion as demonstrated in (b) and (c). Applying absolute stability with lag screws buttressed by a plate, the nonunion healed after three months as shown in (d) and (e).

Fig. 5

Infected nonunion. Treatment of a staphylococcus aureus infected nonunion in a 31-year-old male. (a) and (b) show the status after implant removal with debridement, local antibiotics plus external fixation. (c) and (d) depict the situation after resection, and compression plating. Debridement should be rigorous but careful. Intraoperative lesion of the femoral artery treated by a vascular endoprosthesis.