Residency Insight -- A PRESENT Podiatry eZine

Ryan Fitzgerald, DPM
PRESENT RI Associate Editor
Hess Orthopedics & Sports Medicine
Harrisonburg, Virginia

Case Presentation Conclusion:
21 Year old female with right foot pain

We received a number of excellent responses from YOU regarding the management of this challenging patient on this case presentation E-talk thread, Follow this link to read your colleagues’ comments and to post your own. The conclusion and discussion of this case presentation are posted below.

Course of Care:

In this particular case, the patient, interestingly enough, presented to the office with a known diagnosis; she was referred by an out-of-town orthopaedic oncologist as a surgical consult for an enchondroma in her right 4th metatarsal. The benign tumor had been noted on serial radiogaphs and had been evaluated on MRI. The patient had been told by the previous physician that surgery could be performed to address this pathology, remove the benign tumor, and attempt to resolve her pain. However, considering the non-malignant nature of her condition, the patient’s preference was to hold off on surgery until she was home from college for the summer. That way she could have the procedure performed locally by a foot and ankle specialist.

All of the patient’s records were obtained and both current and previous serial radiographs of the patient’s right foot were compared and reviewed. The radiographs demonstrated an unchanged lesion in the 4th metatarsal with undulating benign 1A margins, which was consistent with the information presented in the consultation from the orthopedic oncologist. All of the various risks, benefits, and potential outcomes were discussed with the patient, and she did elect to undergo correction of this deformity at this time.

Figure 1: pre-operative fluoroscopy image

Consent was obtained and the patient was brought to the operating room for curettage of the enchondroma, bone graft placement, and internal fixation. General anesthesia and local anesthesia, in the form of an ankle block, were used. A 5 centimeter linear longitudinal incision was made dorsally over the middle to distal aspect of the 3rd interspace. Dissection was continued through soft tissue, which was normal in appearance, down to the leval of the 4th metatarsal periostium. K-wire drilling was used under fluoroscopy to properly identify the distal and proximal margins of the lesion. Upon reflection of the periosteum, the identified area of the bone lesion was gray in coloration and noticeably soft and weak upon palpation with instrumentation. Utilizing a small osteotome, a window in the lesion was opened on the lateral aspect of the metatarsal. The lesion’s debris was then resected via curretage to healthy viable bony margins, which were confirmed with fluoroscopy. The resected lesion left a defect measuring less than 2 centimeters in length along the metatarsal shaft. During the surgery, a pathology specimen was obtained from the distal aspect of the 4th metatarsal that was sent for pathologic evaluation which confirmed the diagnosis of enchondroma.

Tibial bone graft was then harvested from a 3 centemeter incision made just lateral to the tibial tubercle, through a 1x1cm cortical window made in the proximal met-diaphyseal flare of tibia. 3mL of cancellous graft was impacted into the defect. A Synthes 9 hole recon plate was cut to 8 holes and placed dorsolaterally over the lesion. Two 2.4mm screws were placed distally, three 2.4mm screws were placed proximally, and 2 screw holes were left empty across the span of the defect. The subcutaneous tissues were reapproximated with 3-0 vicryl and the skin was reapproximated using 4-0 monocryl. A plaster reinforced bulky jones dressing was then applied.

Figure 2: intra-operative flouroscopic image after curretage, cancellous bone graft placement, and internal fixation

Discussion:

Enchondromas are considered the most common benign bone tumor in the hands and feet. They arise from mature hyaline cartilage in the metaphyseal region of long bones and are generally located either centrally or eccentrically along the medullary canal. Enchondromas in the foot occur in younger adults, with a peak incidence in one’s late twenties. Presenting symptoms may include pain, swelling, mild limitation of movement, thickening of tissues, and/or pathological fracture. Radiological characteristics of an enchondroma include a slow-growing(grade Ia or Ib), well circumscribed, oval area of decreased density. It’s margins surrounding the often cloudy matrix may be sclerotic. Microscopically, enchondromas demonstrate lobules of hyaline cartilage cells with calcifications scattered peripherally. This “islands of cartilage” pattern is a definitive sign of the lesion’s benign character. Treatment for an enchondroma can include intralesional curettage with or without cancellous bone grafting and internal fixation. Enchondromas rarely degenerate to malignancy and have a very low recurrence rate. In the foot, however, it is sometimes difficult to differentiate an enchondroma from a secondary chondrosarcoma. Concern for malignancy is warranted if the lesion exceeds 5cm, arises in the midfoot or hindfoot, demonstrates a strong and obvious periosteal reaction, and/or coincides with a soft tissue mass. Oillier’s disease(multiple enchondromatosis) along with Maffucci’s syndrome(multiple enchondromatosis with hemangiomas) are non-inherited dyschondroplasias, evident before puberty, and have a much higher predisposition to malignancy.

I appreciate the many great responses we received from those of you who participated in this case presentation. As always, we look forward to hearring from you. I encourage you to post your interesting cases in the eTalk section of PRESENT podiatry to promote our collective knowledge.

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References:

Banks, Downey, Martin, Miller, eds. McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, Volume 2, 3rd edition. Philadelphia: Lippincott Williams & Wilkins, 2001.
Eur Radiol. 2001;11(6):1054-7. Low-grade chondrosarcoma vs enchondroma: challenges in diagnosis and management. Wang XL, De Beuckeleer LH, De Schepper AM, Van Mark E.
Foot Ankle Int. 2006 Apr;27(4):240-4. Differentiating clinical and radiographic features of enchondroma and secondary chondrosarcoma in the foot. Gajewski DA, Burnette JB, Murphey MD, Temple HT.
Ortop Pol. 2005;70(5):331-5. Clinical signs and methods of treatment of enchondromas located outside the hand. Drelich M, Mazurkiewicz T, Warda E, Kopacz J.
Singapore Med J. 2008 Oct;49(10):841-5; Clinics in diagnostic imaging: Multiple enchondromatosis in Ollier disease. Khoo RN, Peh WC, Guglielmi G