Dorsal Closing Wedge Osteotomy for the Treatment of Freiberg's Infarction

Dorsal Closing Wedge Osteotomy For The Treatment Of Freiberg's Infarction: The Short-term results of 11 patients

Background Freiberg's infarction is an uncommon painful disorder affecting most commonly the 2^nd and the 3^rdmetatarsal heads. Objective To evaluate the results of dorsal closing wedge osteotomy with joint debridement in the treatment of of Freiberg's disease. Methods Eleven patients (4 men) with Freiberg's infarction were treated by joint debridement and dorsal closing wedge osteotomy of the metatarsal neck. The lesion was located in the head of the 2^ndmetatarsal in 10 cases and in the head of the 3^rd metatarsal in one. After the osteotomy the lesion was rotated away from the joint so that the smooth and healthy plantar portion of the articular surface articulated with the proximal phalangeal base. The average follow up period was 15 (12-18) months. Results The subjective outcome was excellent or good in 9 patients, fair in one and poor in one. Conclusion Dorsal closing wedge osteotomy and joint debridement is a technically easy and useful procedure in the treatment of resistant cases of Freiberg's infarction.

Key Words:    Freibergs, Osteotomy

Introduction

Freiberg's infarction is situated in the dorsal part of the articular surface of the head of the second or third metatarsal. It is considered to be a trabecular stress injury caused by excessive pressure on the metatarsal head during weight bearing leading to repeated microfractures, loss of blood supply to subchondral bone, collapse of cancellous bone, and cartilage deformation.^[1] Non-operative management of Freiberg's disease includes modification of shoe wear, rest, modulation of activities and NSAID's.

Surgical management in case of failed conservative methods includes resection of the metatarsal head, elevation of the depressed segment of the head and bone grafting the defect, joint debridement, excision of the base of the proximal phalanx, replacement of the metatarsal head, metatarsal head remodeling, and dorsal closing wedge osteotomy of the metatarsal neck. ^[1]

Dorsal closing wedge osteotomy of the metatarsal neck was first described by Gauthier and Elbaz in 1979 ^[2] and has since been reported with success by other authors. ^{[3],[4],[5],[6]}

The aim of this work is to evaluate the short term results of dorsal closing wedge osteotomy with joint debridement in the treatment of symptomatic cases of Freiberg's disease resistant to conservative treatment.

Patients and Methods

Eleven patients (4 men) were treated by dorsal closing wedge osteotomy with joint debridement after failed conservative treatment. The mean age was 23 years (18-30). The lesion was located in the head of the 2^nd metatarsal in 10 cases and in the head of the 3^rd  metatarsal in one.

Smillie ^[7] described a  classification for this condition based on antero-posterior and oblique radiographs (Table 1).  According to this classification 4 cases were Stage III, 6 cases were stage IV, and one case was stage V.

(Table 1) Smillie's classification 

Surgery was performed under general or spinal anaesthesia.

A tourniquet was applied. A gently curved dorsal incision over the head of the metatarsal and the MP joint was performed. The joint was opened. The operative findings were similar in all patients. The articular cartilage of the metatarsal head was softened and the joint was incongruent. Subchondral bone was collapsed over the dorsal ?  to ½ of the articular surface. The plantar portion of the articular surface was intact in all cases. (Figure 1,2)

The joint was debrided, and any loose bodies or hypertrophic synovium were removed. The lesion on the articular surface was not removed. A dorsal wedge was removed from the normal dorsal metaphysis. (Figure 1,2) The size of the wedge removed depended on the size of the lesion so that the lesion was rotated dorsally and proximally. The length of the metatarsal was preserved as much as possible.

Internal fixation was performed with a figure of (8) stainless steel wire loop. (Figure 1,2)  A walking cast with a toe platform was applied. Stitches were removed at 2 weeks, and the cast discarded at 4 weeks. Then the patients were instructed to use soft shoes and avoid strenuous activities for another 4 weeks.

The clinical results were graded on a 100-point subjective scale for the small toe MP and IP joints. ^[9] The scale measured the level of pain (No pain = 40 points), function (maximum = 45 points), and alignment (maximum = 15 points). A score of 90 or more was considered to be an excellent result; 80-89 points, a good result; 70-79, a fair result; and 69 points or less a poor result.

Results

The patients were followed up clinically and radiographically for a mean period of 15 (12-18) months. There were no cases of deep infection, non-union of the osteotomy site or further narrowing of the MP joint.

The average metatarsal shortening was 1.5 (1-3) mm. One patient complained of transfer metatarsalgia and the metatarsal shortening in this patient was 3 mm. The mean improvement in the level of pain was 24 points (from 7 preoperatively to 31 postoperatively) on a visual analog scale where severe pain = zero points and no pain = 40 points. Postoperatively, there was a mean loss of passive flexion of 13° (10-20), and a mean loss of passive extension of 4° (0-10) of the MP joint. Four patients had an excellent result at the final follow up examination, 5 had good results and one had a fair result. One patient had a poor result.

Discussion

Freiberg's infarction is an uncommon disorder.Freibergrelated this disorder to acute trauma, but a review of the literature indicates that many patients don't give history of significant acute trauma, but rather, repeated loading of the metatarsal head. A stress fracture of the metatarsal head may develop which may eventually evolve into Freiberg's infarction ^[3],[6]

Non-operative treatment may be considered in the early stages including activity modification, casting, and orthoses with metatarsal pads. Surgical treatment is considered after failure of conservative treatment. Many techniques have been described for the surgical management of Freiberg's infarction, but most of them are salvage procedures. ^[5]

Dorsal closing wedge osteotomy was first described by Gauthier & Elbaz. ^[2] The osteotomy moves the lesion away from the articulation with the proximal phalanx and decompresses the metatarsal head leading to relief of symptoms.^[9] It preserves the joint and restores its congruity with a high proportion of good results, regardless of the stage of the disease. ^[6]

Gauthier and Elbaz ^[2] in their original description used stainless steel wiring for fixation of the osteotomy. On the other hand Chao et al.^[6] used percutaneous crossed K wires which were removed 4 weeks later. They claimed that K wires were easier to apply and their only disadvantage was the need to remove them before weight bearing was allowed. In our series we used stainless steel wiring and found that it was easy to apply and that it did not require removal as K wires. Furthermore, it avoided the potential pin tract infection commonly encountered with percutaneous K wires.

Gauthier and Elbaz ^[2] removed the diseased portion of the articular surface, but Kinnard & Lirette ^{[3],[4]^as well as Chao et al.}[6]^ modified the procedure by removing the wedge from the healthy metaphysis at the edge of the joint, and the lesion was just rotated proximally and dorsally away from the articulation with the proximal phalanx. We have used this modification in our series.

Chao et al. ^[6] reported one patient with transfer metatarsalgia in their series of 13 patients. This patient had 3 mm postoperative shortening of the metatarsal. In our series we also had one patient with transfer metatarsalgia with 3 mm postoperative shortening of the metatarsal. However this responded favourably to applying a soft metatarsal pad in the shoes and activity modification. The overall grading for that patient was fair.

Chao et al. ^[6] reported an average loss of plantar flexion of 15°, while in our series the average loss of plantar flexion was 13°. They also reported an average loss of dorsiflexion of 8°, while in our series the average loss of plantar flexion was 4°. This loss of the ROM did not cause any limitation in walking or practicing daily activities in most patients.

We find that dorsal closing wedge osteotomy and joint debridement is a technically easy and useful procedure in the treatment of resistant cases of Freiberg's infarction, with reliably good results in most patients.

References

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