How To Detect Second Metatarsal Pain

Treating forefoot metatarsalgia can be very challenging. In these cases, you’ll often find several differing types of pain and it may be difficult to differentiate the pain according to the patient’s complaints. Be aware the region most often misdiagnosed is forefoot pain surrounding the second metatarsal region. With this in mind, let’s address differing complaints surrounding the second metatarsal region by considering the following case study. A 40-year-old female patient comes into the office, complaining of pain in the region of the second metatarsal. She feels pain with ambulation and it worsens with increased ambulation. With continued walking or activity, she feels a chronic sharp pain in the region of the second metatarsal head and surrounding tissues. She also says she has increased pain at the ball of the foot when she wears high heels and you detect some numbness of the second toe at the distal tip. The patient has no history of trauma and says the pain increased in the previous three to four months from a dull ache to a chronic state. The patient also notes an increased contracture of the second toe in the previous one to two weeks. She reports the pain is slightly better when she uses anti-inflammation medications.

What The Examination Reveals

During the physical examination of the patient, you see mild edema and erythema beneath the second metatarsal head and surrounding tissue. You don’t see any callus tissue and you note there is no fluctuance in the deep space of the second metatarsal head. Upon performing the vascular examination of the foot, you find normal dorsalis pedis and posterior tibial pulses. You also note the patient’s muscle strength to the foot is intact and normal with no loss of muscle function. However, the second toe has a slight contracture at the metatarsal-phalangeal joint (MPJ) and the proximal interphalangeal joint. There is a slight length difference among the first, second and third metatarsals, as the second metatarsal is slightly longer than the first and third. You also see an associated hypermobility of the first metatarsal-cunieform joint. The patient has a positive Lachman’s dorsal drawer of the second MPJ with associated severe pain. Palpating the second interspace causes pain with pressure and you notice the second interspace has a fullness. However, there is no palpable click. The pain in the second interspace does not radiate into the toes nor does it radiate proximally into the rest of the foot and ankle. Palpating the plantar surface of the second MPJ and interspace causes greater pain as you place pressure closer to the second MPJ. You note the pain is greater under the second MPJ as you progressively place pressure distally from the metatarsal head toward the attachment of the toe. The patient’s gait pattern reveals mild pes planus. You notice an associated early heel off pattern secondary to a slight equinus deformity. The patient feels pain when you ask her to stand onto her tip toes but she relates no shooting pain. When you examine radiographs, you see a slightly elevated first metatarsal and a slightly long second metatarsal. The patient has a mild hammertoe associated with the second toe proximal interphalangeal joint. You also note mild deviation of the second MPJ into an adductus position.

What Is The Differential Diagnosis?

1) Second interspace neuroma 2) Hammertoe contracture with second metatarsal contracture 3) Second metatarsal phalangeal joint synovitis 4) Long/plantarflexed second metatarsal 5) Plantar plate tear of the second MPJ

Key Tips On Adjunctive Tests

An MRI is my choice test in this situation. Although it’s hard to identify a neuroma on MRI, often, there is an associated interspace edema without involving the second MPJ that helps with a possible neuroma diagnosis. When it comes to a plantar plate rupture or partial tear, this is often visible on MRI and you can also diagnose it indirectly when your patient has increased signal in the plantar surface of the second metatarsal head and phalynx base. You can also use an MRI to visualize joint synovitis. You may also consider using a diagnostic ultrasound as a second test, but be aware it is very technician-dependent. Using this modality may help you see a neuroma or a plantar plate tear. Also keep in mind that fullness of the MPJ may indicate a chronic synovitis. An arthrogram of the second MPJ is an excellent test for diagnosing a possible plantar plate tear of the second MPJ, but be aware that it may be negative if there is scar tissue healing of the plantar plate region. In cases of chronic scarring, the dye material will not leak into the flexor tendon sheath.

Diagnostic Answers

1. An interspace neuroma of the second web space is very rare in my opinion and I will not make this diagnosis without seeing a great deal of evidence. I rarely will inject a patient in the interspace until I have received the MRI results and decided a neuroma is highly likely. In this case, there is no sharp or shooting pain in the second interspace and there is no palpable click. The patient also has a pain beneath the second MPJ, which is not usually present with a neuroma. 2. Although there is a hammertoe of the second toe with some contracture at the MPJ, the second toe has no pain except at the distal tip and the toe is flexible. The contracture of the second MPJ is easily reducible and the plantar metatarsal head has no callus. 3. Synovitis of the second MPJ is possible yet there is rarely pain on the plantar region of the joint and most of the pain is on the dorsal aspect with this diagnosis. Often, the synovitis is due to a primary underlying issue, which you’ll need to diagnose. 4. While we see a long metatarsal on radiographs, you can’t consider this diagnosis as the primary source of pain since there is no callus under the metatarsal head and the pain is distal to the metatarsal head in the region of the phalangeal base. 5. The diagnosis in this case is most likely a plantar plate tear of the second MPJ. Plantar plate tears are often misdiagnosed or overlooked so be on the lookout for several common findings in cases of plantar plate tears. The most common finding you’ll see is a hypermobility of the first metatarsal. This causes an overload of the lesser metatarsals, leading to a plantar tear of the associated capsule. Other common findings of the first metatarsal are an elevated first metatarsal (commonly due to a hallux valgus deformity) or a short metatarsal. Although the pain is often caused by a lack of function in the first metatarsal, the tear may be directly caused by the associated metatarsal. In most cases, you’ll find a long metatarsal in association with the plantar plate tear. It is also common to see a contracted proximal phalanx, which is flexible. In long-standing cases, you may also note a medial or lateral deviation of the toe at the MPJ. Finally, you’ll often see an equinus deformity leading to an early heel off and increased forefoot loading.

Diagnosis And Treatment

Remember that employing cortisone injections will only provide temporary pain relief and will result in a decreased rate of healing of the torn plantar plate. You’ll often see plantar plate deformities in the second MPJ, but be aware that this pain is closely related to a second MPJ neuroma. If you’re not careful in the diagnostic process and fail to undertake a neuroma treatment regimen, the problem will not subside and a frustrated patient ultimately will leave your practice disappointed. As noted earlier, I will not treat a second MPJ problem until I am either sure a plantar plate tear does not exist or until I have received an MRI. Although an MRI is not always diagnostic, there are some helpful diagnostic pearls to remember. With a plantar plate tear, you’ll see associated swelling of the MPJ plantar capsule region, which also extends along the associated flexor tendon. In the case of an interspace neuroma, if you can’t directly identify the neuroma on the MRI, you will see inflammation in the interspace instead of in the capsular region. In treating the plantar plate tear of the second MPJ, you want to stabilize the MPJ in order to allow healing. To see if stabilization will be beneficial, tape the toe in a plantarflexed position and allow the patient to take a few steps. If he or she feels relief from pain, undertake a course of conservative care. I often will try three to four weeks of MPJ stabilization with a toe stabilization pad and surgical shoe. If the treatment does not resolve pain at the two-week appointment, I will begin a course of physical therapy, including electrical stimulation and ultrasound of the painful region. At the four-week point, if there is no change in the patient’s pain whatsoever, I will consider surgical repair. Although direct repair of the plantar plate is possible, there is a general consensus that a flexor to extensor transfer is the preferred technique. You would do this in conjunction with fusing the proximal interphalangeal joint of the associated toe and releasing any MPJ contracture. It is essential to transfer the long flexor tendon as close to the base of the proximal phalanx as possible. Otherwise, you cannot recreate the function of the plantar plate. Pin the MPJ for three to four weeks. After this period, remove the pin from the MPJ and start range of motion of the joint. Do not remove the pin from the interphalangeal joint until you note a solid fusion. Only in cases of severe MPJ contracture is it necessary to decrease the length of the metatarsal. In conclusion, take care in diagnosing second metatarsal deformities and interspace neuromas. More often than you may imagine, a plantar plate may be the underlying problem. Dr. Baravarian is an Assistant Clinical Professor in the Department of Surgery/Division of Podiatric Surgery of the UCLA School of Medicine. His e-mail address is Bbaravarian@mednet.ucla.edu.