Session V - Foot and Ankle

The Mangled Foot and Ankle: The Role of Soft Tissue Coverage

Michael J. Bosse, MD¹; Renan C. Castillo, MPH; Dolfi Herscovici, Jr., DO²; Thomas G. DiPasquale, DO²; Ellen J. MacKenzie, PhD; ¹Carolinas Medical Center, Charlotte, North Carolina, USA ²Tampa General Hospital, Tampa, Florida, USA (-NIH Grant)

Purpose: Severe injuries to the foot and ankle require significant reconstructive surgery for salvage. Many authors feel that amputation in these circumstances result in a superior functional outcome. One determinate in the literature has been whether or not the patient will require a bulky free tissue transfer, as in many situations this will make shoe wear untenable. This study was undertaken to determine the functional outcome of the mangled foot and ankle undergoing salvage, with and without the need for free tissue transfer, and compare this cohort to a similar group undergoing below knee amputation.

Materials and Methods: The study population consisted of 182 open and mangled lower extremities (130 foot, 11 ankle and 41 pilon). All injuries were irrigated and debrided and provisionally stabilized at the time of injury. Neurovascular assessment, soft tissue loss, bone loss, and other systemic factors were applied to a treatment algorithm intra-operatively, and decisions were then made regarding the need for an immediate or early amputation. Excluding the early amputees, there were 74 foot, 9 ankle and 33 pilon fractures that remained. Reconstructive salvage was then performed, including staged internal fixation, and delayed wound closure (with/or without STSGs), or free vascularized tissue transfers. All patients (amputees and salvage) were then followed for two years. Follow-up data recorded included: SIP scores, percent with walking speed >4 ft/sec, number of re-hospitalizations for complications, time to full weight bearing, visual pain scores and return to work rates. Regression analysis was used to determine, what effect, if any, the use of free tissue transfer had on the outcome of these patients. The impact of ankle fusion was also assessed.

Results: All of the BKAs were closed employing typical skin flap designs. 37/66 had 2 year follow-up. In the reconstruction cohort, free flaps were needed as follows: foot salvage 10/60 2 yr follow-up (16.6%), pilon salvage 7/29 (24%), ankle salvage 1/5 (20%). The two year results can best be seen in table form:

Two-Year SIP Outcomes

	Overall SIP	Physical SIP	Psychosocial SIP
BKA (standard coverage)	13.20	10.73	12.08
Foot Salvages	11.92	10.00	11.02
Pilon Salvages	10.94	9.43	7.32
Ankle Salvages	15.22	13.11	13.79

Multivariate Regression Results at 24 Months

	Overall SIP	p-value	Physical SIP	Psycho-social p-value	SIP	p-value
Foot Injury	-3.6	.14	-2.2	.30	-4.0	.20
Ankle/Pilon Injury	-3.7	.16	-1.8	.45	-6.7	.06
Free Flap	+6.7	.02	+2.6	.30	10.3	01
Ankle Fusion	+8.3	.02	+6.9	.02	7.7	.09

19.2% of the reconstruction patients required free tissue transfers. The regression analysis showed a significant negative effect of both free flaps and ankle fusions on the SIP score: a free flap added 6.7 points, a fusion =8.3. Further analysis showed that where a standard soft tissue coverage had a significantly better SIP score than a BKA, the addition of a free flap or a fusion reversed the result. All salvage patients had significantly more re-hospitalizations and longer times to full weight bearing. Return to work rates, walking speeds and pain were not different.

Discussion: This information can be used to educate a patient and the patient's family during the limb salvage decision making process. Longer follow-up is required to see if the differences are stable over time.