Foot Arthrodesis

Definition

What is an arthrodesis?

An arthrodesis is the fusion of a joint. When the joint can be preserved, it is preferable to maintain mobility, even if it is only slight. Joint mobility in the ankle and foot is important because no one walks the same way, and it is difficult to "adjust" an arthrodesis while taking into account all the individual parameters of patients.

An arthrodesis of a joint can be considered permanent; the joint will then be permanently locked.

In certain specific cases, it is possible to undo an arthrodesis to place a prosthesis. This is called a dis-arthrodesis – prosthesis procedure, which can be considered for the ankle and the big toe.

How exactly does an arthrodesis take place?

To achieve joint fusion, it is essential to remove all remaining cartilage from the joint. This is the first surgical step and is crucial to increase the chances of successful fusion.

After cartilage resection, it is necessary to refresh the subchondral bone, that is, to make the bone under the original cartilage bleed. This can be done using motorized or non-motorized instruments. Bone is worked much like wood; in fact, we prefer using curettes and bone chisels, similar to wood chisels. Motorized instruments can cause slight localized bone resorption due to the heat of the burr or saw blade.

Perforations of the subchondral bone are made using small curved bone chisels, further increasing the chances of joint fusion by bringing bone cells into the joint and improving the stability of the arthrodesis.

Finally, the arthrodesis must be fixed with surgical hardware. We can use screws, locking plates, or staples. The aim during hardware placement is to compress the bone surfaces to be fused and to neutralize the joint.

A cast immobilization is done depending on the joint or joints to be fused.

The arthrodesis is monitored using standard X-rays and, if necessary, a CT scan from 3 months post-operation.

What are the advantages and disadvantages?

An arthrodesis can address several anatomical problems at the same time. In cases of bone loss, osteoarthritis, and articular or extra-articular deformity, arthrodesis is a way to address all these issues in a single procedure.

In cases of severe traumatic lesions with tissue damage, evolution can lead to pain from soft tissue envelopes in addition to osteoarthritis. Arthrodesis then allows the peripheral tissues to rest, and it also relieves residual pain in the soft tissue envelope.

On the other hand, it is difficult to find an arthrodesis position adjustment that suits each patient, their habits, and lifestyle.

Fusing a joint increases the mechanical stress on neighboring joints, with a risk of osteoarthritis developing in them in the medium or long term.

Surgical techniques for arthrodesis

Open techniques

Classically, arthrodesis of the foot joints is performed through conventional, open surgery. The procedure involves incising the skin, then the capsuloligamentous structure to access the joint. Joint release is performed, known as arthrolysis, allowing correct exposure of the joint surfaces. The joint surfaces are then refreshed, the subchondral bone is perforated, and fixation is achieved with surgical hardware. The setup depends on the joint involved, its load during walking, the bone stock, and the need to add a bone graft. If a bone graft is used, this is called a reconstructive arthrodesis.

Arthroscopic techniques

More rarely, foot arthrodesis can be performed by arthroscopy. Exposure of the joint may require distraction to access the joint. Distraction can be manual or with the help of dedicated distraction instruments. Refreshing of the joint surfaces is done with motorized instruments and a curette. Perforation of the subchondral bone is performed using dedicated instruments. Surgical fixation is achieved with hardware introduced percutaneously.

Indications for arthrodesis

Osteoarthritis

Osteoarthritis is the main indication for arthrodesis of the foot joints. While arthrodesis remains the most commonly used surgical technique for osteoarthritis of the foot, some joints are suitable for prosthetic replacement, particularly the metatarsophalangeal joints and the lateral Lisfranc joints.

Foot deformity

Certain foot deformities can be treated with conservative procedures, thus allowing some degree of joint mobility to be maintained. These are joint release procedures that may include correction osteotomies, ligament reconstructions, and tendon transfers. If conservative surgery is not reasonably possible, arthrodesis is performed.

Foot dislocation

Joint dislocations in the foot are rarely treated with acute arthrodesis. Reduction of the dislocation to restore joint congruence and possible surgical stabilization is indicated acutely.

Chronic dislocations, especially in the medial Lisfranc area, may be treated with arthrodesis.

Sequelae deformities

In cases of sequelae deformities of the foot, if the joints are unstable, the tissues contracted, and there is low bone stock, arthrodesis may be considered.

Results and complications

The Results

The time frame for achieving the outcome of an arthrodesis varies depending on the joint involved, the number of joints to be fused, and the correction of deformities made during the procedure. Overall, it should be considered that the final result of the arthrodesis is obtained one year to a year and a half after the operation.

Complications

It is possible that the arthrodesis does not fuse, in which case it is called a pseudoarthrosis. This pseudoarthrosis can be painless, and in that case, no additional treatment is required. However, it may be painful and, depending on the level of disability, may require another operation with an additional bone graft.

The hardware may also become bothersome over time. Removal of the hardware may then be suggested. In cases of fused or non-fused arthrodesis where painless hardware is present, it is preferable to keep the hardware in place.

In general, surgical hardware that is not bothersome does not require systematic removal. It will always be possible to remove it if it becomes painful over time.

Conclusion

Arthrodesis can be the only possible treatment for certain painful joints, especially those of the hindfoot and midfoot.

For some joints, prosthetic replacement allows mobility to be maintained, relieving neighboring joints and preserving adaptive mobility for changes in terrain and for footwear.