[Arthrodesis of interphalangeal joints by means of external frame fixation]

The indications for arthrodesis of interphalangeal joints include pain, instability, deformity or irreparable damage to the relevant flexor or extensor tendon. The general principle of arthrodesis is to resect the affected joint ends in the flexion desired so that a highest possible surface of contact may be provided. Subsequently, retention by means of internal or external fixation is performed. The aim of this study is to evaluate our method of interphalangeal joint arthrodesis, using an external frame fixator, to present the results and to point out the advantages of this method, thus showing its applicability for relevant surgical indication.

Arthrodesis by external fixation was carried out in 37 patients. The group included 21 men and 16 women at an average age of 49.6 years (range, 30 to 67 years). The method was used in the patients who differed in the etiology of lesions of interphalangeal joints. Twenty-two patients had previously experienced purulent arthritis, six had post-traumatic arthritis and joint instability, five had rheumatoid arthritis, two had primary arthritis and two had an inveterate rupture of the extensor aponeurosis.

We used a simple frame fixator whose stability was based on two to four Kirschner's wires inserted and maintained in clamps on rods, 4 cm or 7.5 cm long, each having a double anti-clockwise thread that facilitates compression, distraction and correction in one plane. The surgical procedure was carried out under axillary block with the use of a tourniquet. It involved making an S-shaped incision dorsally, severing the extensor apparatus, resecting articular surfaces in the desired flexion position, inserting parallel wires and fixing them in clamps on rods, achieving compression, checking the position of articular surfaces and suturing. Included in the group assessment were the gender and age of the patients, etiology of articular disease, number of the digits and joints affected, limb laterality, wound healing, stability of fixation, maintenance of a correct arthrodesis position and signs of healing on X-ray images. Time required for bony union and the shortening of the digit due to surgery were also included in the evaluation.

The 35 followed-up patients showed healing of the wound and arthrodesis, with firm bony union being achieved at an average of 6.7 weeks. In one patient after removal of the fixator, septic pseudoarthrosis developed at the site of the resected distal interphalangeal joint. Another patient developed ischemia of the distal phalanx of the thumb treated, which required release and subsequent removal of the external fixator, with vasodilatation therapy. After a prolonged topical therapy, painless fibrous ankylosis developed in that interphalangeal joint and the thumb was salvaged.

The aim of arthrodesis is to achieve firm and painless bony union in a correct functional position at a reasonable time. Arthrodesis in our patients healed at an average time of 6.7 weeks. The high effectivity of the compression technique in achieving firm bony fusion is the factor emphasized in the literature, particularly in situations where there is a reduced contact surface, poor coverage by soft tissue, infection or the presence of a systemic disease, such as rheumatoid arthritis or diabetes mellitus. This all is in agreement with the results of this study.

This study shows advantages of the compression technique of arthrodesis by means of external frame fixation based on insertion of wires beyond the site of inflammation. Compression and stability result in rapid osseous union, immobilization in plaster cast is not necessary, free joints of the hand can be exercised, the fixator is removed in an outpatient department and the minimal presence of metal material does not interfere with good healing of soft tissues. Therefore this method has all merits to be used for surgery in a terrain affected by rheumatic, inflammatory or potentially inflammatory lesions.