Does the IOFix implant improve union rates?

Abstract

Background: First metatarso-phalangeal joint fusion is the current gold standard for severe hallux rigidus. Data regarding the union rate and the re-operation rate when IOFix (an Intra-osseous fixation device, Extremity medical, New Jersey, USA) is used for hallux rigidus fusion is limited but promising. The aim of this study was to review our outcomes with the IOFix implant.

Methods: We have conducted a retrospective chart review, following the approval of the hospital IRB committee. Exclusion criteria included bilateral operations on the same patient, multiple surgeries, charcot foot or other structural foot abnormalities (except hallux valgus), rheumatoid arthritis and a recent foot trauma. We collected demographic data, physical examination documentation, functional score evaluations (AOFAS), and Plain radiographic studies.

Results: Thirty patients were included in the study. The mean age was 60.36 ± 9.12 (range 36 to 77) years, 18 (60%) female patients and 12 (40%) male. Fourteen (53.33%) were left side pathologies. The average follow up period was 36.2 ± 12.31 (range 12 to 54) months. Union was obtained in 28 (93.33%) patients, of whom none had requested a hardware removal due to a prominent hardware during a minimum of 2 year follow up period. The mean postoperative AOFAS score was 80.5 ± 10.87 (range 35 to 90). A more stringent inclusion criteria and fusion definitions would have led to an exclusion of two more patients and a dropout of two patients from the "fused" group, which would have led to a fusion rate of 85.71%.

Conclusions: This is the largest series of hallux rigidus patients that were operated with an IOFix device. The rates of fusion and hardware removal in MTPJ1 arthrodesis performed with an IOFix implant were found to be similar at most when compared to previously described rates that were obtained with other cheaper and more simple fixation devices.

Level of evidence: 4.

Keywords: Fusion; Hallux rigidus; IOFix; Union.

Fig. 1

A treatment protocol for hallux rigidus

Fig. 2

An intra-operative photo of a first metatarsophalangeal joint showing a destruction of more than 50% of the cartilage on the metatarsal side. This finding lead to a decision to fuse the joint rather than to conduct a cheilectomy procedure

Fig. 3

A standing X ray radiograph of a patient with bilateral hallux rigidus that was considered as severe

Fig. 4

A standing X ray radiograph of a patients who was operated for a hallux rigidus with an IOFix implant. This patients suffered from a hardware protrusion. In this case a technique failure has led to the unwanted complication

Fig. 5

A non-symptomatic non-union of an arthrodesis of a first metatarso-phalangeal joint that was operated with an IOFix implant