Simultaneous femoral bifocal non-union compression and lengthening over an intramedullary nail. A novel technique and case report

Ipsilateral concomitant femoral neck and shaft fractures are indicative of a high-energy injury; treatment options for the management of this acute combination of fractures include composite fixation of both fractures using a reconstruction nail type implant, fixation using a standard antegrade femoral nail with associated but separate cancellous screw fixation of the femoral neck, independent fixation of each fracture with screw and plate constructs, and external fixation. Femoral non-union following intramedullary nailing of closed fractures is an common and recognised complication, with rates 6 to 18% quoted in the literature, most frequently seen with reconstruction nail fixation [1-5]. Management of shaft non-unions is typically treated with exchange nailing and/or grafting, in this high-energy injury group complications are more prevalent and multiple procedures more likely [4].

Management of simultaneous complications is more troublesome, and may typically require sequential treatment of each issue. The Ilizarov Method is a powerful technique for the management of deformity, limb lengthening, trauma and non-union [6]. Circular external fixation permits the simlutaneous management of segmental pathology within one limb segment and can be applied to the treatment of complex post-traumatic pathology and failure of initial and convential treatment. The subsequent development of the Hexapod computer-assisted circular external fixators (e.g. Ortho-SUV frame, Pitkar, Pune) has permitted multiplanar correction under precise control [7] and more rapid correction than the traditional Ilizarov frame, particularly with complex deformity [8]. In recent years, the technique of Lengthening-over-Nail (LON) has been developed, predominantly to reduce frame time and improve patient comfort [9-11].

This is the first report of a bifocal Non-union compression over an intramedullary nail and coincident LON which appears to be a powerful and minimally invasive technique to address two separate post-traumatic complications simultaneously.

CASE PRESENTATION AND TECHNICAL REPORT

A 38 year old man was involved in a motor vehicle collision during which he sustained a comminuted left femoral fracture with an associated ipsilateral femoral neck fracture (fig. 1).

He was treated in a major trauma centre with a Gamma Nail (Stryker, MI, USA), with significant inadvertent segmental comminution (fig. 2).

At 18 months following injury, his femoral neck fracture had united, however there was an established atrophic nonunion with shortening of five centimetres of the femoral shaft fracture and fracture of the distal locking screws. The knee extensor mechanism was defunctioned due to the increased working length of the quadriceps in relation to the short femoral segment and clinical instability of the knee was documented.

Weightbearing was commenced immediately, and the non-union portion of the frame sequentially compressed. Simultaneously, distraction was applied across the corticotomy site (fig. 4), with five centimetres of distraction achieved after 16 weeks.

Femoral union was achieved at six months. Regenerate was considered sufficiently structural at nine months and the frame removed and nail locked at this point in time. The nail was subsequently removed at 18 months from commencement of frame treatment and whilst no overt sepsis had been noted in the femur, the Reamer Irrigator Aspirator (Synthes, PA, USA) was used to debride the intramedullary canal following removal.

Fig. 1. Initial radiograph showing simple Fig. 2. Radiograph after initial stabilisation               Fig. 3. Initial bifocal frame midshaft femoral fracture                      with comminution of fracture site

Fig. 4. Appearance during combined         Fig. 5. Fully united and consolidated non-         Fig. 6. Fully united and consolidated distraction and compression                     union and regenerate                               non-union and regenerate

CONCLUSION

LON is a powerful tool in limb lengthening, providing a clear trajectory for osteogenesis and permitting early locking of the nail and weightbearing with reduction of the External Fixation Time Index. However, no reports of this occur with a significant interval between nail insertion and delayed lengthening. No published studies describe external fixator compression of femoral non-unions with a nail in situ although plate fixation of a non-union with a nail in situ has been reported in a single case [12] and there is some experience of the use of compression over a nail with a monolateral fixator in the humerus [13].

Lengthening over nail can significantly reduce frame time [9-11], and here has been shown to be achievable with frame application temporally remote from nail insertion. Non-union compression utilising circular fixation is well known [14], however in the presence of a femoral intramedullary nail this has not previously been described. Technical difficulty can occur with half pin insertion with the nail in situ however with careful technique the half pins can be inserted into the femoral cortex tangential to the nail.

Hexapod fixators such as the Taylor Spatial Frame and the Ortho-SUV frame have been shown to be at least as effective as the original Ilizarov frame in lengthening and deformity correction, with reduced frame size with subsequent improved patient acceptance and more precise control of multiplanar deformity during a single frame application [7,8].

This report confirms the breadth of utility of the application of circular fixation as a method to simultaneously address significant pathology within long bones, and introduces a further mode of application for the management of complications of internal fixation.

Consent

The patient has provided informed consent for the case report to be published.

Competing interests

None