When Sesamoid Pain Complicates Hallux Limitus Cases

By Babak Baravarian, DPM

   As I get more in tune with patient care, I find that the simple cases such as hallux limitus are more difficult than I initially thought because they are often more complicated and involved than the original examination might show. I have come to this conclusion after being burned by a couple of trouble cases and learning what to look for as a result.    A typical patient is a 47-year-old female with chronic pain in the great toe. She has trouble in dress shoes and has mild limitation of shoegear. The patient reports having mild pain when playing golf and there is some redness of the dorsum of the foot with ambulation and activity.    An examination of the region shows mild dorsal spurring and limitation of motion to 25 degrees of dorsiflexion and 20 degrees of plantar motion. She has mild dorsal pain to pressure and her end range of dorsal motion shows mild crepitus. There is no gross pain in the plantar metatarsal head and she has no medial pain and no gross stiffness or clicking of the joint.    Radiographs show a very small dorsal spur. There is no gross deviation of the joint or gross arthritic changes of the joint. The patient does have mild elevatus of the first metatarsal.    Although there is elevatus of the first ray on radiographs, the first ray is slightly plantar to the other rays when the patient is at rest or in a non-weightbearing position. With standing, the ray elevates due to some laxity of the first metatarsocuneiform region.

Discussing The Initial Treatment Options

   We discuss the options with the patient. The first treatment option is a cheilectomy type spur resection. The second option is to osteotomize the region and decompress the joint although there are no severe arthritic changes. The third option is to remove the spurring from the metatarsophalangeal joint and then perform a first metatarsocuneiform fusion to stabilize the first ray. The patient understands the recovery and potential for a good outcome are best with a simple cheilectomy and she agrees to undergo that procedure.    The surgery is uneventful. After we remove the spurring, the patient’s range of motion of the great toe at the metatarsophalangeal joint increases to 70 degrees of dorsal motion. However, there is mild clicking and crepitus of the joint with motion. I check the cartilage and find it to be pristine within the joint surface. An examination of the crepitus shows the pain is from the plantar surface of the joint and dissection reveals moderate degenerative changes in between the tibial sesamoid and plantar first metatarsal region. I remove the region of poor cartilage from the plantar metatarsal head and drill the area to allow for fibrocartilage ingrowth.    I explain to the patient there are arthritic changes of the tibial sesamoid and she understands this problem. She has an uneventful recovery and begins to ambulate on the region. The dorsal pain resolves but there is continued pain in the plantar first metatarsal region. MRI shows severe arthritis of part of the tibial sesamoid on the surgical side with moderate arthritis of the plantar first metatarsal head adjacent to the tibial sesamoid.

Understanding The Causes Of Arthritic Sesamoid Pain

   The question is not how to treat the arthritis but rather how one can be more aware of this problem and question the type of surgery and cause of the arthritis as a primary problem.    Why is the problem hard to diagnose in the initial visit? I believe it is due to the lack of pain in the area and the lack of gross tenderness in the tibial sesamoid region. Furthermore, there is poor motion of the great toe, limiting the gliding and rubbing of the tibial sesamoid against the arthritic metatarsal region. With the additional motion following spur resection and cheilectomy, there is greater motion of the tibial sesamoid, which results in more pain.    First and foremost, one needs to watch for sesamoid arthritis in cases of hallux limitus. I have seen more of these when I have looked for it than one could imagine. In most of the cases, the problem is mild with minimal involvement and one can leave it alone. If there is crepitus with motion and pressing the sesamoid with motion of the toe causes pain, one should obtain a MRI or CT scan of the area to see the amount of arthritis prior to the surgery. Secondly, I discuss the possible need for a more extensive surgery with the patient.    The cause of the sesamoid damage is still a mystery to me. If a patient has elevatus of the ray with ambulation and laxity at the first metatarsocuneiform region, how can there be arthritis of the sesamoid region? I believe there is actually a plantarflexed first ray when the patient is non-weightbearing and that it jams dorsally with weight on the foot. This jamming in combination with pronation may cause the tibial sesamoid to get overloaded and arthritic in nature.

A Few Thoughts On Treatment For Sesamoid Arthritis

   As for treatment options, I believe the osteotomy type of decompressions of the metatarsal head allow for better motion and less stiffness of the great toe joint. However, the main advantage of performing these procedures is being able to change the position of the metatarsal head. This may allow one to move the articular surface more proximally and decrease the stress on the tibial sesamoid as well as allow the tibial sesamoid to glide against a different region of better quality cartilage. Therefore, there may be more benefit to performing a metatarsal head osteotomy as opposed to performing just decompression.    The second option is a tibial sesamoid resection. Although we have all been taught to watch for hallux valgus in cases of tibial sesamoid removal, hallux limitus cases are often associated with a square head pattern and very stable medial and lateral motion of the great toe. In order to be safe, a lateral release may be indicated as well as release of the extensor hallucis brevis tendon. This will often be enough to prevent a case of hallux valgus in the normal hallux limitus foot type.    A final option is to remove the dorsal spurring without dramatic resection to prevent excessive dorsal motion of the great toe and then drill the sesamoid apparatus and metatarsal head arthritic lesions. One should stabilize the region for a period of time and emphasize limited motion for six to eight weeks in order to allow for some scar formation. This will prevent excessive tracking of the tibial sesamoid and pain in certain cases.

In Conclusion

   It is essential to watch for both sesamoid and metatarsal head articular damage on the initial workup of hallux limitus even in the most simple of cases. If one suspects arthritic sesamoid changes, one may want to obtain a MRI or CT scan of the foot and alert the patient at the initial visit to the potential need for further surgery or more involved surgery. This will help prevent us from having unhappy patients. Dr. Baravarian (shown here) 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 via e-mail at: bbaravarian@mednet.ucla.edu.

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