Arthrodesis

Arthrodesis is orthopaedic surgery that permanently fuses the affected joint to correct a deformity or to obtain pain relief.
Cartilage, which is a white flexible tissue, covers joints and allows them to move and work properly. A final and stable fusion is obtained by removing the cartilage and putting the underlying bone structures into contact via screws or a plate system. The indications and benefits of this type of surgery range considerably.

Patients often fear arthrodesis due to a lack of information; however, it can correct a considerable number of issues and it remains a major option in the treatment of foot and ankle conditions.

Hallux valgus, Arthrodèse cunéo-métatarsienne avec excision articulaire et plaque plantaire

Fig. 1 and 2

Cuneo-metatarsal arthrodesis for the treatment of hallux valgus. Note the removal of joint cartilage (in green) and installation of plate/screws to fuse the bone in position

Indications and options
Arthrodesis is used to correct many conditions and deformities. It is traditionally indicated for patients who have cartilage damage, such as arthritis, with fairly significant wear to the cartilage. While mild cases can be treated conservatively, progression to severe arthritis may require the removal of the joint either by fusion (arthrodesis) or its replacement with a prosthesis (e.g. ankle replacement). This last option is only valid for certain joints and specific conditions.

Potentially, any joint affected by arthritis can benefit from arthrodesis. In the foot, the most common fusion sites are:
- Hallux rigidus (arthritis of the big toe)
- Ankle arthritis
- Lisfranc joint line
- Post-traumatic subtalar arthritis (between the astragalus and calcaneus)
- etc.
Fig. 3: Arthrodesis of the hallux via screws for the treatment of arthritis of the big toe

Indications are not limited to arthritis. Arthrodesis also offers considerable stability when correcting highly unstable or severe structural deformities. In this context, this surgery is mainly focused on:
- double or triple arthrodesis for rigid flat feet
- cuneo-metatarsal arthrodesis for unstable hallux valgus
- interphalangeal arthrodesis for hammertoe
- realignment arthrodesis for congenital deformities
- severe trauma
- etc.
Limitations and implications

Naturally, the first negative effect of arthrodesis is the definitive blockage of joint mobility. Although it is often requested, it is important to understand its effect on the mechanics of the foot and its implication on daily activities. The repercussions vary considerably depending on the joint concerned and the surgeon must fully informed patients before this type of surgery.

Equally, activity on the neighbouring joints will increase to compensate for the limitation due to the blockage following the arthrodesis. Arthritis in the neighbouring joints commonly accelerates after the fusion.
And this situation is often observed in ankle arthrodesis cases. In such cases, the activity of the joint located between the heel bone and astragalus (the sub-talar joint) is greatly increased following the ankle blockage, and the cartilage degenerates faster, if it is affected by arthritis. A second arthrodesis, in the sub-talar region, is then required.
The overall status of joints in the entire forefoot should be evaluated before suggesting an arthrodesis. When arthritis in the ankle is accompanied by diffuse arthritis of the hind- and mid-foot, a replacement is preferred to arthrodesis to protect the already injured joints.
Risks and complications
The aim of arthrodesis is to fuse two bony structures together. The first possible complication is the absence of fusion, which is also called pseudarthrosis. Certain factors increase this risk such as:
- smoking
- infection at the arthrodesis site
- lack of stabilisation, either due to the choice of the implanted material or poor quality fixation (osteoporosis)
- failure to comply with post-surgical recommendations (walking bearing/not bearing weight, plaster, etc.)
- certain treatments (chemotherapy, radiotherapy, etc.)
Post-surgical radiological monitoring to check the fusion of bony elements. In principle, it will take three months before radiological signs of consolidation are observed after an arthrodesis. These will obviously depend on the location and external factors. In the event of proven pseudarthrosis, further surgery is usually required to increase the stability of the orthopaedic device and to add a bone graft.

Another classic complication is fusion in the incorrect position or a poor union. In fact, the direction and position of the bone are determined on the day of the surgery, during the final fixing. Any correction error will trigger a potential and possibly symptomatic deviation of the bony areas. If this effect is painful or causes a hyper-support, further surgery on the site is sometimes required either via de-arthrodesis and a new arthrodesis, or by additional bone surgery (corrective osteotomy).
Post-surgical follow up

The post-surgery treatment depends on several factors. The location of the arthrodesis, the quality of the fixation, any associated procedures, etc., are all elements involved in the post-surgery rehabilitation. The lower limb is generally protected by a resin splint to limit movements during the consolidation phase. Equally, no weight must be placed on the affected area when walking.

Arthrodesis involving the forefoot (big toe, toes, etc.) does not generally impose a non-weight requirement or splint and walking is permitted with orthopaedic footwear.

Follow-up radiography will be carried out six weeks, three months and six months after surgery. These checks ensure the bone is fusing properly and, on a surgical level, that good progress is being made. The removal of the restraint system or a return to daily and sporting activities is dependent on such checks.

Like any foot surgery, patience is required during the rehabilitation phase. Blocking the joint will inevitably result in biomechanical changes to the foot, which can sometimes take time for the body to integrate. Physiotherapy sessions can be required to accelerate functional recovery.
Conclusion

Arthrodesis is a very powerful tool used to treat orthopaedic conditions. Its indications are very specific but, when correctly placed, it can result in a stable and long-term correction of sometimes major deformities. Its fixing position and external factors during the healing phase are very sensitive issues, and it must be carried out with great accuracy, with knowledge of its use and limitations. A good understanding of the instructions is vital to the success of this surgery and patients must ensure they obtain all of the information required to complete the treatment from the doctor.

Arthrodesis

Indications and options

Limitations and implications

Risks and complications

Post-surgical follow up

Conclusion