Treating Lesser Metatarsal Stress Fracture Following A First MPJ Cheilectomy

This author details how to manage postoperative stress fractures following a first metatarsophalangeal joint cheilectomy in a 56-year-old patient.

A 56-year-old healthy female presented with a referral for “dorsal bunions.” She has a ten-year history of progressive pain, which is greater in her right forefoot than left forefoot. The patient previously failed treatment with orthotics, shoegear modifications and topical anti-inflammatories. She has a negative tobacco history and a past medical history of asthma.

She is a 5-foot, 6-inch, 165-pound female. The patient has pain on palpation to ectopic bone growth on the dorsal aspect of the first metatarsophalangeal joint (MPJ) and pain at end range of motion. Her range of motion is symmetric bilaterally.

Radiographs show first MPJ joint narrowing and ectopic bone growth on the lateral aspect of the proximal hallux and adjacent metatarsal on a dorsoplantar view. Lateral radiographs demonstrate dorsal ectopic bone formation on the first metatarsal head. Classically, these are grade II hallux limitus findings.

Treatment discussions led to a decision for first MPJ cheilectomy. The surgical procedure involved a dorsal incision and full flap dissection. I used a rongeur to remove exuberant bone growth from the dorsal and lateral aspect of the proximal phalanx and the lateral aspect of the metatarsal head. After using a sagittal saw to remove the dorsal spurring off the metatarsal head, I proceeded to a standard closure technique. On the table, the patient's range of motion improved in comparison to preoperative testing.

The patient bore weight immediately after the procedure and wore a standard post-op shoe. She received instructions for heel weightbearing at the time of surgery. 

A Closer Look At The Patient’s Post-Op Pain

At one-month follow-up, the patient had minimal discomfort and an expected amount of surgical site swelling. The radiographs were unremarkable. She proceeded to regular supportive shoegear and I told her to refrain from athletics and painful activities.

At the two-month follow-up, the patient's surgical site was pain-free but she had developed pain at her third intermetatarsal region. She described the sensation as “burning” and “numbing.” Her radiographs were unremarkable. I diagnosed a third interspace neuroma and performed a cortisone injection at that two-month postoperative visit.

At her next visit three months post-op, she had continued pain in the lateral forefoot and had swelling over the forth metatarsal distally. Radiographs showed a transverse fracture at the fourth metatarsal neck with dorsal lateral displacement and early callus formation locally. I recommend that the patient return to the surgical shoe and decrease her activities. The subsequent four-month post-op follow-up exam showed a stable non-tender fracture and healed surgical site.

What The Literature Reveals About Post-Op Stress Fractures

There are multiple literature accounts of postoperative stress fracture of the lesser metatarsals. The most commonly reported is second metatarsal stress fracture following a Keller bunionectomy or first MPJ implant arthroplasty.^1-3 Kitaoka and colleagues theorized this was due to overloading of the lesser metatarsals as a result of some shortening or the reestablishment of motion to the hallux.³ I did not perform shortening with an isolated cheilectomy in this case but the reestablishment of first MPJ range of motion may play a role in lateral metatarsal overload.

However, after I discussed postoperative habits with this patient, she demonstrated her gait, which revealed pushing off the lateral foot to avoid pressure on the surgical site more medially. This change most likely accounts for the biomechanical lateral overload postoperatively.  

Further literature examples of postoperative lesser metatarsal fractures involve osteotomies of the first ray or insults to the affected second ray. Sammarco and coworkers reported two of 88 second metatarsal stress fractures following proximal chevron osteotomy for hallux valgus correction.⁴ More recently, Weatherall reported that eight of 25 (32 percent) patients who had hallux abducto valgus repair with TightRope (Arthrex) fixation developed postoperative second metatarsal stress fractures.⁵

In Conclusion

This was my first experience of a confirmed postoperative stress fracture. Even though the patient was wearing a hard bottom protective shoe during early recovery, she was weightbearing through her lateral column in an attempt to avoid putting weight on her medial surgical site. My diagnosis of a neuroma was based on her symptom description, my clinical exam and radiographs. However, a higher index of suspicion for lesser metatarsal stress fracture would have led to recommendations for protection and likely averted a through and through fourth metatarsal fracture. Ultimately and fortunately, she obtained the desired results of a pain-free foot postoperatively.

Dr. Bussewitz is a fellowship-trained foot and ankle surgeon who practices at Steindler Orthopedic Clinic in Iowa City, Iowa.

References

1. Friend G. Sequential metatarsal stress fractures after Keller arthroplasty with implants. J Foot Surg. 1981;20(4):227-31.

2. Zechman JS. Stress fracture of the second metatarsal after Keller bunionectomy. J Foot Surg. 1984;23(1):63-5.

3. Kitaoka HB, Cracchiolo A. Stress fracture of lateral metatarsals following double-stem silicone implant arthroplasty of the hallux MTPJ. Clin Orthop Rel Res. 1989;239:211-16.

4. Sammarco GJ, Russo-Alesi. FG. Bunion correction using proximal chevron osteotomy: a single-incision technique. Foot Ankle Int. 1998;19(7):430-7.

5. Weatherall JM, Chapman CB, Shapiro S. Post-operative second metatarsal fractures associated with suture-button implant in hallux valgus surgery. Foot Ankle Int. 2013;34(1):104-10.