The aim of this study was to evaluate the patient reported outcome measures (PROMS), radiological outcome and complications when performing a triple arthrodesis using the IOFIX system for the talonavicular and calcaneocuboid joints.

Data was collected prospectively. Twenty-nine consecutive patients were reviewed 1 year postoperative. Outcomes analysed were rate of fusion, American Orthopaedic Foot and Ankle Society (AOFAS) score, Visual Analogue Scale (VAS), patient satisfaction and complications.

Complete fusion was achieved in 90 %. The mean preoperative AOFAS score improved from 42 (95 % confidence interval: 22-43) to 75 (95 % confidence interval 67-82) postoperative and the mean VAS improved from 6.5 (95 % confidence interval 4.9-8.6) to 4 (95 % confidence interval 3.1-4.9), p < 0.001. There was an early complication rate of 13 %. After 1 year 86 % were satisfied and there was a complication rate of 3 %.

This study suggests that the IOFIX system offers a reliable and performant alternative technique for patients undergoing a triple arthrodesis.

Level II, prospective cohort study.

Arthrodesis of a (diseased) ankle joint is usually performed to achieve pain relief and stability. One basic principle of arthrodesis techniques includes rigid fixation of the surfaces until union. It seems plausible that stable anchoring and homogeneous pressure distribution should be advantageous, however, it has not been investigated yet. The aim is to achieve uniform compression, as this is expected to produce favorable results for the bony fusion of the intended arthrodesis. Numerous implants with different biomechanical concepts can be used for ankle fusion. In this study, headless compression screws (HCS, DePuy Synthes, Zuchwil, Switzerland) were compared biomechanically to an alternative fixation System, the IOFix device (Extremity Medical, Parsippany, NJ, USA) in regard to the distribution of the compression force (area of contact) and peak compression in a sawbone arthrodesis-model (Sawbones® Pacific Research Laboratories, Vashon, WA, USA). This study aims to quantify the area of contact between the bone interface that can be obtained using headless compression screws compared to the IOFix. In current literature, it is assumed, that a large contact surface with sufficient pressure between the bones brings good clinical results. However, there are no clinical or biomechanical studies, that describe the optimal compression pressure for an arthrodesis.

Two standardized sawbone blocks were placed above each other in a custom-made jig. IOFix and headless compression screws were inserted pairwise parallel to each other using a template for a uniform drilling pattern. All screws were inserted with a predefined torque of 0.5 Nm. Pressure transducers positioned between the two sawbone blocks were compressed for the measurement of peak compression force, compression distribution, and area of contact.

With the IOFix, the compression force was distributed over significantly larger areas compared to the contact area of the HCS screws, resulting in a more homogenous contact area over the entire arthrodesis surface. Maximum compression force showed no significant difference.

The IOFix system distributes the compression pressure over a much larger area, resulting in more evenly spread compression at the surface. Clinical studies must show whether this leads to a lower pseudarthrosis rate.

The complication rate for an arthrodesis of the first metatarsophalangeal joint remains high. To improve results, we used a complete intraosseous fixation device (IOFIX) with proposed biomechanical advantages. Our hypothesis is that this technique has at least an equal union rate and less hardware irritation compared to other techniques. Seventy procedures were performed in 55 patients. Average follow-up was 24.5 months. All patients returned to follow-up after 6 weeks and were evaluated for union. Fifty-nine feet (84%) completed full follow- up. Union occurred in 62 of 70 feet (88.5%). Eight feet had nonunion at 1 year follow-up. Average time to fusion was 51 days. Three of 59 feet had malunion. No hardware removal was necessary. In conclusion, an MTP1 arthrodesis using IOFIX provides consistent and good functional outcomes. Due to the low-profile design, no hardware removal was necessary. However, union rates seem slightly lower compared to other techniques.

We describe a new surgical technique for arthrodesis of the first tarso-metatarsal (TMT) joint using an intraosseous fixation device and the early results including patient-reported outcome measures (PROMS).

Seventeen consecutive procedures with this method were included. Indication for surgery was hallux valgus. The average age was 42 years (range 26-65). PROMS were collected and the patients were asked to fill out a satisfaction questionnaire. A retrospective review of radiographs and electronic medical notes was conducted.

Overall fusion rate was 94%. Complications included a case of failed fusion, a superficial wound infection and a deep vein thrombosis (DVT). At a mean follow-up of 24 months (range 10-38) radiographic results demonstrated significant improvement in the intermetatarsal angle or IMA (11.7 ± 2.8 degrees to 6.9 ± 2.4 degrees, P < 0.001) and hallux valgus angle or HVA (28.1 ± 7.3 degrees to 12.2 ± 4.3 degrees, P < 0.001). The mean visual analog scale (VAS) score improved significantly from a mean of 7.6 (SD 0.85) preoperatively, to a mean of 2.1 (SD 1.83) post-operatively (P < 0.0001). The Manchester-Oxford Foot Questionnaire (MOXFQ) significantly improved from a mean of 35.8 (SD 10.2), to a mean of 9.2 (SD 17) (P < 0.0001). The final result was satisfactory for 88% of the patients.

The early results show intraosseous fixation to be a safe and efficient method for the fusion of the first TMT joint providing good patient satisfaction.

Arthrodesis is the surgical fusion of a diseased joint for the purposes of obtaining pain relief and stability. There have been numerous fixation devices described in literature for foot and ankle arthrodesis, each with their own benefits and drawbacks.

To review the use of intraosseous devices in foot and ankle surgery.

There were 9 papers included in the review (6 clinical and 3 experimental studies) all evaluating arthrodesis in the foot and ankle using the IOFIX device (Extremity Medical™, Parsippany, NJ, United States). Outcome scores, union rates, as well as complications were analysed.

IOFIX appears to be safe and effective in achieving arthrodesis of the 1st metatarsophalangeal, and talonavicular joints with early rehabilitation. In comparison to plate/screw constructs there were fewer soft tissue complications and issues of metalwork prominence. Cadaveric and biomechanical studies on the use of intramedullary fixation for fusion of the tarsometatarsal and ankle joint showed decreased load to failure, cycles to failure and stiffness in comparison to traditional fusion methods using plates and screws, however IOFIX devices produced higher compressive forces at the joint.

We describe the reasons for which this biomechanical behavior of the intraosseous fixation may be favorable, until prospective and comparative studies with larger sample size and longer follow-up confirm the effectiveness and limitations of the method.

Functional outcome of first metatarsophalangeal joint (MTPJ) arthrodesis using intramedullary implant was reviewed in retrospective series of 12 patients who had MTPJ arthritis. The outcome measures were improvements seen in VAS for pain and AOFAS scores recorded pre-operatively and post-operatively at the time of achieving complete union. VAS for pain improved from mean of 7.5 pre-operative to 1.8 post-operative (p < 0.001). AOFAS Score improved from mean of 35.58 pre-operative to 80.91 post-operative (p < 0.001). The fusion rate was 100 percent and mean time needed for fusion was 9.6 weeks. Only one patient had malunion which was acceptable to patient and was not revised. The fusion using intramedullary intra-osseous Hallux Fusion implant is a promising technique with good functional outcome and low complications.

Arthrodesis is the gold standard procedure for advanced arthrosis of the first metatarsophalangeal joint. Having a strong construct is preferable for allowing immediate bearing of weight, which facilitates patient rehabilitation. Plate and screw fixation is currently in favor but can lead to prominent metalware necessitating removal. The aim of this study is to report the results of a series of 54 first metatarsophalangeal joint arthrodeses performed in 52 patients treated with an implant composed of an intraosseous post and lag screw. All of the patients had a minimum follow-up of 1 year, and the indication for the surgery was end-stage hallux rigidus in 44 (81.5%) feet, severe hallux valgus in 8 (14.8%) feet, and rheumatoid arthritis in 2 (3.7%) feet. Arthrodesis was achieved in 52 (96.3%) feet at a mean of 61 ± 16 (range 39 to 201) days with nonunion observed in 2 (3.7%) feet; neither of the 2 patients had known risk factors. Metalware impinging on soft tissues necessitating removal was observed in 3 (5.6%) feet, and there were no cases of loss of position or implant breakage. The mean Manchester-Oxford Foot Questionnaire score improved from 46.4 ± 13.3 to 18.4 ± 9.4 (p < .001) at latest follow-up. In conclusion, our results suggest the intraosseous post and lag screw device was safe and effective, and it can be considered an alternative method of stabilizing the first metatarsophalangeal joint when undertaking arthrodesis surgery.

Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a common procedure to treat significant first MTPJ arthritis. However, dorsal plates used for this have been associated with high incidence of metalwork removal. The IOFIX (Intra-Osseous FIXation) is a fixed angle device that is noted to provide a more uniform compression over a larger aspect of the fusion surfaces than a screw construct alone with the advantage of minimizing soft tissue irritation which can reduce the need for subsequent implant removal.

Twenty one consecutive patients who underwent primary first MTPJ fusion with the IOFIX were reviewed. The mean age of the cohort was 63 years (range 47-81), with 80% female. The ratio of left to right was 9:12. The mean follow up of was 28 months (range 13.4-48.2 months). Outcomes analyzed were rate of fusion, Manchester-Oxford foot questionnaire (MOXFQ) score, patient satisfaction, improvement in the intermetatarsal angle and complications.

Complete fusion of the first MTPJ was achieved in twenty (95%) patients. One patient had a non union and another patient developed a delayed union. The mean preoperative MOXFQ score improved from 49.7 (95% confidence interval: 46-52) to 17.9 (95% confidence interval: 12-22), p<0.05.Improvement gained in all the domains of the MOXFQ score (walking/standing, pain and social) was statistically significant (p<0.05). Eighteen out of 21 patients (85%) were very pleased or fairly pleased with the procedure.

Early results show that the rate of fusion achieved by using the IOFIX device for the first MTPJ arthrodesis in our series was found to be comparable to other devices quoted in the literature.

Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation.

Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint.

The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method.

The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that which can be obtained with 3 headless compression screws. Screw and external fixator performance did not correlate with bone mineral density. This study supports the use of external fixation as an alternative method of generating compression to help stimulate fusion across the transverse tarsal joints.

The findings provide biomechanical evidence to support the use of external fixation as a viable option in transverse tarsal joint fusion cases in which screw fixation has failed or is anticipated to be inadequate due to suboptimal bone quality.