When Second MPJ Overload Occurs Without Hammertoe Deformity

Author(s): 
By Babak Baravarian, DPM

   It is not uncommon to see one patient every day on my practice schedule who has pain and inflammation of the second metatarsophalangeal joint (MPJ). While there are cases that involve a hammertoe associated with metatarsophalangeal joint pain, what are the options for treating patients who have pain in the second metatarsophalangeal joint but do not have a hammertoe deformity?    When it comes to cases of so-called “capsulitis of the second MPJ,” we try all kinds of different therapy with little consideration of a proper diagnosis and diagnostic testing. Furthermore, we never develop a true treatment plan for such a problem. With this in mind, let us take a closer look at this condition.    The patient who commonly presents to my practice is between the ages of 35 and 50 and has either acute or more chronic onset of pain in the second MPJ. The pain tends to be subtle and increasing with mild fullness of the ball of the foot and mild tenderness to pressure on the second MPJ plantar aspect. There is often pain with high heels and hard-soled shoes but these patients may also experience pain with flat shoes.    Patients commonly note that the pain has gradually increased with time and they often have a limp when they present to my office. While there is no history of trauma, these patients tend to experience pain with every step and it is not associated with a specific time of day or event during the day. The pain does seem to get worse with increased activity.    One may also note some mild swelling of the plantar surface of the ball of the foot with mild erythema. While there is no gross hammertoe deformity, one may note some mild laxity of the joint with dorsal drawer testing. There is no varus or valgus deviation of the second toe but there is often a very mild dorsal contracture of the toe with an extensor contracture to the second digit. Clinicians may often note an underlying hallux valgus deformity with a mild to moderate deformity that is not a severe cause of pain. The patient may have mild to moderate laxity of the first ray and a slight equinus deformity that is more associated with a tight gastrocnemius muscle than the actual Achilles tendon itself. There is also no callus in the plantar aspect of the second metatarsal head.

Emphasizing Key Diagnostic Steps

   When evaluating these patients, our first step is obtaining radiographs of the feet. If there is any question of ankle deformity or possible impingement of the ankle contributing to the equinus problems, we also take radiographs of the ankle. We take all films with the patient in full weightbearing in order to achieve a proper foot and ankle position and base of gait. We review the films to ensure there is no stress fracture or metatarsal overload fracture, bone tumor, signs of avascular necrosis or cartilage defect of the metatarsal head.    Radiographs are particularly useful for checking the alignment of the foot, the length of the first through third metatarsals and the parabola of the forefoot. I often add a plantar axial image if there is gross hypermobility of the first ray and have the X-ray shot in such a way to see if there is a first ray elevatus versus a generalized forefoot varus. This is an essential part of the general biomechanical workup.    I often pursue an ultrasound examination of the foot in my diagnostic examination of these patients. This enables me to check the plantar plates of the metatarsal heads for laxity and drawer, gross tear and also for the laxity of the joint. I also check the interspaces for any signs of a soft tissue mass or neuroma formation in the region. If I identify a neuroma, I treat it accordingly. However, for the purposes of this article, let us assume there is no neuroma.    It is very easy to check the plantar plate and one must treat a tear or partial tear accordingly. However, in most cases, one will not see a tear and the only finding is laxity of the joint with easy dorsal motion of the digit to 80 or 90 degrees dorsiflexion.

Addressing The Possible Treatment Options

   Treatment options are very dependent on the findings. Accordingly, let us consider the following findings and subsequent treatment.    Laxity of the first ray and hallux valgus causing overload of the second MPJ with no length issues of either ray. The treatment option for such a case includes orthotic therapy with a second ray cutout and physical therapy for pain relief. If conservative care does not work, consider performing a midfoot fusion Lapidus type bunion surgery to stabilize the medial column and relieve stress on the second ray.    Forefoot overload due to equinus of the Achilles tendon or gastrocnemius complex. The treatment for such a case includes physical therapy for a stretching program and relief of forefoot pressure and pain. One would subsequently emphasize orthotics therapy and stretching by the patient at home. If this treatment course proves unsuccessful, consider a gastrocnemius recession or Achilles tendon lengthening.    Long second metatarsal compared to the overall length of the first and third metatarsals. Conservative treatment should include physical therapy to calm down swelling and pain, and orthotic therapy that employs a cutout below the second metatarsal head to relieve stress on the region. In my experience, these cases are rare and surgical treatment is rarely indicated. However, in the rare case of a grossly long second metatarsal, consider a shortening procedure if conservative care fails.    If there is any extensor contracture of the second MPJ, one may use a Weil type osteotomy. However, if the ray is stable, performing a distal shaft osteotomy will allow one to shorten the ray without opening the capsule. This procedure also facilitates better preservation of the joint.    A stable but short first ray. This finding is fairly common and also very difficult to treat. In these cases, the first ray is not unstable but is short in comparison to the lateral rays. There may be a slight hallux valgus but not enough to warrant surgery. I see most of these cases after attempted surgeries with shortening of the ray leading to lateral overload.    Conservative care in these cases includes physical therapy to calm down the joint and forefoot pain. One would subsequently use orthotics with a metatarsal pad, adding a Morton’s extension below the great toe to add stress to the region and incorporating a possible second MPJ cutout or added forefoot padding.    I try to avoid any form of surgery in these cases as it usually does not work well. In my experience, bunion correction is truly not much help as performing a head osteotomy often leads to further shortening. I have also noted transfer lesions with the second metatarsal osteotomy and do not recommend such a procedure. As a last resort treatment, performing a Lapidus style hallux valgus correction with bone graft offers moderate to good outcomes for at least keeping if not lengthening the first ray. I also try to plantarflex the first ray slightly in order to take mildly added pressure away from the second ray and MPJ.    Laxity of the second MPJ in a normal forefoot. This is fairly rare by itself but one may commonly note this with other findings. Utilizing orthotic therapy with a second MPJ cutout can be useful in addition to physical therapy to calm the region.    With these cases, I treat this problem as a pre-dislocation syndrome with plantar plate overload. I often will consider a flexor to extensor transfer with or without fusion of the digit. The digital fusion is not necessary if the ray is stable without a hammertoe deformity. The flexor transfer allows more stability of the ray and joint, and limits the abnormal dorsal motion.

In Conclusion

   The overall treatment plan in my eyes is quite simple. Do not inject the region as this may cause a plantar plate rupture. Try local physical therapy, which may be slower but also has far fewer risks. Orthotic therapy is well tolerated and often has a high level of success. Try a Morton’s extension if the first ray is short, a cutout below the second MPJ and toe and/or a metatarsal pad to decrease strain of the metatarsal heads and add cushion to the ball of the foot. Also post the forefoot in cases of varus forefoot or an elevated first ray.    In regard to surgical treatment, I will choose the needed procedures that address the foot as a whole entity instead of just treating the symptomatic region. When it comes to second MPJ pain without hammertoe deformity, the most common surgical procedure I perform is a midfoot fusion Lapidus hallux valgus correction to stabilize the medial column. Use bone graft in the fusion site if the ray is short. I am also not shy about performing a gastrocnemius recession procedure but try to stay away from Achilles lengthening. I stay away from parabola corrections and usually do not perform many lesser metatarsal osteotomies. I perform flexor transfers commonly, especially if I suspect a plantar plate tear or severe overload.    I believe the issue in such cases is the problem is painful but not severe enough to cause chronic debilitating pain associated with such presenting complaints as fractures and tendon tears. In these cases, reconstructive surgery, including tendon lengthening or midfoot fusion, sounds far too complicated for such a simple problem. However, one must treat the foot as a whole.    Too often, these patients are neglected until there is a plantar plate tear and dislocation of the second MPJ or severe midfoot arthritis of the lesser metatarsals due to an untreated hypermobile first ray. Do not be afraid to be aggressive with a simple problem if this will save the patient years of pain and problems to come. While one should stay conservative with primary treatment options, we should also keep the long-term prognosis in mind. Dr. Baravarian (photo) 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 the Santa Monica/UCLA Medical Center. Dr. Baravarian may be reached via e-mail at bbaravarian@mednet.ucla.edu.

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