Essential Insights On Treating Freiberg`s Infraction

As practitioners of the foot and ankle, some conditions and their treatment options become second nature to us. For example, it seems we are fairly comfortable with the treatment options associated with a degenerated first metatarsophalangeal joint. However, what does one do with the patient who has pain at the ball of the foot when X-rays reveal flattening of the second metatarsal head and degenerative changes in the second metatarsophalangeal joint? The answer probably should be, “Well, it depends.” Freiberg’s disease can vary in severity and typically undergoes a progression over time. Accordingly, let us take a closer look at some of the findings and variables with this condition, and review the conservative and surgical treatment options. First described by Freiberg in a review of six cases in 1914, infraction of the metatarsal head is most common in young females. The onset of the condition often occurs in the early to later stages of puberty. Although the etiology is not known for sure, the prevailing thinking is there is a vascular disruption at the epiphyseal plate that is likely secondary to trauma. Repetitive stress can cause microfractures at the junction of the epiphysis and metaphysis. The disease process can be gradual over time as it responds to the repetitive trauma. The onset of this process of aseptic necrosis or osteochondrosis commonly occurs in this patient population while the epiphyseal plate is open. It is not uncommon for a patient to be relatively asymptomatic through this process only to have the condition reveal itself later in life in response to poor shoegear, high heels, increased activity, etc. There is a strong female predilection in Freiberg’s disease with females five times more likely to have the condition than men. An Overview Of Key Findings And Diagnostic Considerations As mentioned above, Freiberg’s disease most commonly affects adolescent girls, especially those involved in athletic activities. The patient typically complains of focal pain at the ball of the foot in the region of the second metatarsal head. The pain is exacerbated with activity and typically increases over time. It is not uncommon for a patient to be asymptomatic during the early stages and for symptoms to develop later in life as a result of the joint degeneration. Radiographic findings can show early osteopenia with subchondral fracture. (See “Infraction Or Infarction?” below) Subchondral sclerosis can develop over time. Flattening of the metatarsal head is a classic sign that one usually sees with this condition, especially later in the patient’s life. The fracture and fragmentation can lead to sclerosis and avascular necrosis of the fragments. Loose bodies can form over time, contributing to the joint degeneration and the symptoms. Authors have presented radiographic classification of this condition in the literature. Smillie’s classification (1967) seems to be quoted most often and is summarized as follows:1 Stage 1: Subtle fracture line through the epiphysis. Stage 2: Central depression. Stage 3: Central depression leads to medial and lateral projections at the margins. Plantar hinge remains intact. Stage 4: Central portion frees from the intact plantar hinge, forming a loose body. Fractures of the medial and lateral projections. Stage 5: Flattening of the metatarsal head with secondary degenerative changes. In most cases, when one is considering surgery, it is a good idea first to obtain a MRI of the forefoot in order to check the surrounding quality of bone and the level of damage to the joint involving the avascular necrosis. The points to consider include: • the amount of cartilage damage; • the location of cartilage damage (dorsal versus the entire surface versus central damage); • the quality of the cartilage and bone surrounding the infarction region; and • the level of degeneration to the base of the associated phalynx. Infraction Or Infarction? Freiberg’s infraction was the term used to describe Freiberg’s disease. This indicated that there was a traumatic etiology involving epiphyseal fracture and fragmentation. This causes a secondary obstruction of local blood flow, leading to an infarction or avascular state of the metatarsal head. Both terms could be appropriate for describing this condition. The infraction may have caused the infarction. There are both vascular and traumatic theories as to the etiology of Freiberg’s disease. Can Conservative Therapies Help? As with almost any condition that we treat in the foot and ankle, the treatment of Freiberg’s disease should focus on the specific patient and the level of degeneration in the metatarsophalangeal joint. While all cases are not surgical in nature, one should keep in mind that early and appropriate treatment is usually more successful than delayed treatment. When it comes to the younger patient who has had an early diagnosis and no internal damage to the joint, it is important to limit activity and immobilize the affected area. We recommend a period of four to six weeks in a non-weightbearing cast during the acute disease process. (One may provide cortisone injections to alleviate an acute presentation of lesser metatarsophalangeal joint pain.) Following this period of immobilization, employing a stiff-soled shoe, rocker bottom, steel shank sole and custom orthotics with a metatarsal bar or a metatarsal shell extension under the affected metatarsal can help limit motion and symptoms in the affected area. Patients should obviously avoid high-heeled shoes. It is important to discuss activity modifications with the patient. Unfortunately, activity restrictions do not go over well with the younger, more active patients. For these patients, clinicians should inform and educate their patients to help ease frustrations and encourage compliance. When Surgery Is Indicated: A Guide To Treatment Options From simple debridement to metatarsal head resection, surgical procedures can alleviate pain and return the patient to an active lifestyle. In cases of limited damage with loose bodies or a small region of cartilage damage, one may perform simple debridement to remove loose bodies, and can couple this with bone grafting to restore a congruous joint in the earlier stages of Freiberg’s disease. Clinicians should take care to keep options open and inform the patient that a decision for an osteotomy type of treatment may be necessary at the time of surgery. Since Freiberg’s disease usually results in dorsal joint collapse and subsequent dorsal joint degeneration with intact plantar cartilage, surgeons may perform dorsal metatarsal wedge osteotomies in order to rotate the healthy plantar cartilage effectively to a more dorsal/central position. One may perform this procedure at the neck of the metatarsal with no damage to the collateral ligaments. The surgeon may rotate the plantar cartilage dorsally through a dorsal-based “v” osteotomy. A simple form of fixation is using crossed K-wires that are bent and buried against the bone. Decompressional or second metatarsal shortening osteotomies are another surgical option for treating Freiberg’s infraction. In addition to addressing one of the possible etiologic causes (long second metatarsal), this procedure also decompresses the affected joint. Surgeons should exercise caution with both types of osteotomy so one may perform a flexor tendon transfer to the involved toe if there is any laxity of the joint. In cases of central osteonecrosis with surrounding normal bone, an OATS type cartilage and bone grafting procedure may be successful. It is essential to use an MRI in these cases in order to see the architecture of the joint. Furthermore, one should inform the patient that this type of procedure may fail either intraoperatively or during the healing period due to the surrounding poor bone stock. Metatarsal head resection should be an option during surgery if the quality of bone is poor. The ideal type of graft is a fresh cartilage and bone either from a cadaver specimen (which is very difficult to find and expensive) or from the talus. The anterior process of the talus has a ridge of non-weightbearing surface ideal for a graft donor site. A medial ankle arthrotomy provides easy access for a 4 to 6 mm graft harvest. A second essential point is to remove all dead bone yet be sure to leave a surrounding ledge of bone in the metatarsal head for graft ingrowth. Although long-term outcomes are lacking, lesser metatarsophalangeal joint implant arthroplasty has been presented as an alternative treatment in Freiberg’s disease. In our opinion, the procedure does not offer the long-term treatment options that we desire. Accordingly, we tend to stay away from implant use in the metatarsal head. However, one may treat end-stage joint degeneration with metatarsal head resection and the use of a natural spacer material. Although there is an inherent potential complication of transfer lesions with metatarsal head resection, it is sometimes the only option. Several authors have presented interpositional arthroplasty. In our opinion, using a cadaveric or autograft tendon as a spacer may help with scar formation as a spacer in the resection site. Again, a flexor tendon transfer is highly suggested in order to prevent dorsal migration of the involved toe. Final Notes In our experience, osteonecrosis of the metatarsal head requires a dedicated clinician and patient relationship. It is important to educate the patient and explain that more than one procedure may be necessary over a lifetime for this condition. Furthermore, if conservative treatment fails, one should obtain an informed consent for several types of procedures prior to surgery as the appropriate treatment may depend on the level of damage uncovered upon examination of the joint. Getting a MRI can be very helpful prior to surgery in checking the joint damage and level of arthritis. Finally, if the surgeon does attempt grafting, it is important to be aware of the failure rate and possible need for metatarsal head resection. Dr. Baravarian is Co-Director of the Foot and Ankle Institute of Santa Monica. He is an Associate Professor at UCLA Medical Center and is the Chief of Podiatric Surgery at Santa Monica/UCLA Medical Center. Dr. Baravarian may be reached at bbaravarian@mednet.ucla.edu. Dr. Franson is affiliated with the Foot and Ankle Institute of Santa Monica.
 

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References 1. Smillie IS: Treatment of Freiberg’s infraction. Proc R Soc Med 1967 Jan; 60(1):29-31.