The slot graft technique for foot and ankle arthrodesis in a high-risk patient group

Locked Dorsal Compression Plate Arthrodesis for Degenerative Arthritis of the Midfoot

Midfoot arthrodesis is the accepted surgical treatment for symptomatic midfoot arthritis. The published literature has focused on joint-spanning static fixation. Several companies have developed diamond-shaped locked dorsal compression plates, which allow for longitudinal joint compression. After dorsal plate insertion, a spreader device opens the arms of the plate mediolaterally, which allows the plate to compress longitudinally. This work describes outcomes of such locked dorsal compression plates for midfoot arthritis at a single institution. We reviewed 62 patients who underwent midfoot arthrodesis for symptomatic midfoot arthritis using locked dorsal compression plates over a 7-year period. A total of 173 joints were spanned for fusion. The primary outcome measure was radiographic union and visual analog scale pain scores. Characteristics of patients who experienced nonunion versus those who had union were evaluated. Of the 173 joints, there was a 81.5% fusion rate (141/173 joints) and 14 patients experienced nonunion. There was a statistically significant difference in the average number of joints spanned in patients with nonunion (3.6) and patients with union (2.5) (p = .02). Locked dorsal compression plate arthrodesis is a viable technique for achieving midfoot fusion. This mechanical method of compression does not, however, lend itself to improved fusion rates compared with prior reports. A greater number of arthrodesis sites is associated with a higher nonunion rate. Emerging technology using newer materials and improved biomechanical designs may show improved results.

Clinical and Operative Factors Related to Successful Revision Arthrodesis in the Foot and Ankle

BACKGROUND

Arthrodesis is a common operative procedure used to manage arthritis and deformity in the foot and ankle. Nonunion is a possible and undesirable outcome in any arthrodesis surgery. Rates of nonunion in the foot and ankle literature range from 0% to 47% depending on the patient population and joint involved. Multiple factors can contribute to developing a nonunion including location, fixation method, tobacco use, diabetes, infection, and others.

METHODS

The case logs of 3 foot and ankle surgeons were reviewed from January 2007 to September 2014 to identify nonunion arthrodesis revision cases. The patient factors reviewed included diabetes, inflammatory arthropathy, tobacco use, history of infection, nonunion elsewhere, neuropathy, Charcot arthropathy, posttraumatic arthritis, and prior attempt at revision arthrodesis at the same site. Operative records were reviewed to identify location of the nonunion, instrumention, use of allograft or autograft bone, use of iliac crest bone marrow aspirate (ICBMA) and use of orthobiologics such as bone morphogenetic protein (BMP) during the revision arthrodesis. Successful revision was defined as radiographic union on the final radiograph during follow-up. Eighty-two cases of revision arthrodesis were identified with an average follow-up of 16 months.

RESULTS

The overall nonunion rate was 23%. Neuropathy and prior attempts at revision were identified as significant risks (P <.05) for persistent nonunion. Odds ratio calculated based on previous attempts at revision arthrodesis found a 2.8-fold increase in the risk of failure for each attempt at revision.

CONCLUSION

Revision arthrodesis for nonunion in the foot and ankle was successful (77%) under a variety of patient and operative conditions. Neuropathy was a significant patient risk factor for persistent nonunions, and we believe it is important to identify even in the nondiabetic patient. As the number of attempts at revisions increases, there is a subsequent 3-fold increase in the risk of persistent nonunion.

LEVEL OF EVIDENCE

Level IV, case series.

Does autogenous bone graft work? A logistic regression analysis of data from 159 papers in the foot and ankle literature

BACKGROUND

While autogenous cancellous iliac crest bone graft is the gold standard for foot and ankle surgery, it lacks Level I evidence. Although one third of all graft cases performed in the United States today rely on allograft, some surgeons believe no graft is necessary. We hypothesized that a systematic review of the foot and ankle literature would reveal that (1) autogenous bone graft during foot and ankle arthrodesis would demonstrate healing rates that were superior to the use of either using allograft or no bone graft at all, and (2) these differences would be even more dramatic in patients having risk factors that impair bone healing. To our knowledge, neither of these assessments to date has ever been performed with this body of literature. The goal of this study was to review the use and union rates of bone graft during foot and ankle arthrodesis and determine if autogenous bone graft was superior.

METHODS

A literature search was performed to include articles between 1959 and 2012 using autograft, allograft, and/or no bone graft for foot and/or ankle arthrodesis. Case reports involving fewer than four patients, investigations failing to incorporate outcome data, those involving orthobiologic augmentation, and those including vascularized graft, xenograft, or pediatric patients were excluded. Recorded search results included patient demographics, comorbidities, pre-operative diagnosis, surgical procedure, bone graft type and indication, union rate, method of fixation, patient satisfaction, all outcome scores, definition of healing/success, and any listed complications including revision. Final data were stratified based upon the type of graft material.

RESULTS

This search generated 953 related articles, of which 159 studies (5327 patients) met inclusion criteria. The majority (153/159) were retrospective case series. Systematic review demonstrated a trend toward higher union rates for cancellous autograft (OR 1.39, p=0.11), structural autograft (OR 1.52, p=0.09), and cancellous allograft (OR 1.31, p=0.52) relative to no graft material, but none reached statistical significance. Compared to no graft, structural allograft trended toward worse performance (OR 0.62, p=0.17). The overall probability of union was 93.7% for cancellous autograft, 94.2% for structural autograft, 93.3% for cancellous allograft, 91.4% for no graft, and 86.9% for structural allograft. When only comparing the 19 papers that included a no graft arm (91.9% union rate), data revealed the highest union using cancellous autograft (95.1%, OR 1.73, p=0.09) and structural autograft (96.3%, OR 2.33, p=0.06) while only 76% for structural allograft. No significant statistical association existed between union rates and other recorded variables.

CONCLUSION

Systematic analysis of bone graft use in foot and ankle fusions favors the use of autograft and cancellous allograft for optimized healing rates, although no differences were statistically significant. If we assume that graft material been chosen for more complex procedures having lower anticipated union rates, then these data lend further support to the use of autograft and cancellous allograft.

LEVEL OF EVIDENCE

Level IV.

Applications of the medial femoral condyle free flap for foot and ankle reconstruction

BACKGROUND

Avascular necrosis (AVN) or persistent nonunion occurs in situations of poor vascular supply. Some specific situations that plague the foot and ankle surgeon are talus nonunion, talus AVN, navicular AVN, and failed ankle arthrodesis with bone loss. The medial femoral condyle (MFC) flap has emerged as a popular source of vascularized corticocancelous bone. We present a series of cases demonstrating the versatility of the MFC flap in complex foot and ankle pathology.

METHODS

A retrospective review was completed of all MFC flaps used in the foot and ankle over the past 5 years. Five patients were identified (average age 48). Surgical indications included talar AVN and ankle arthritis, talar nonunion, and navicular AVN. All patients had undergone conventional bone grafting techniques, which failed, prior to being treated with a MFC free flap; this series of patients did not possess significant medical comorbidities. Fixation techniques included compression screw fixation, plate osteosynthesis, or fine wire external fixation. The average follow-up was 20 months (range 8 to 40 months).

RESULTS

There was a 100% flap success rate with no returns to the operating room for thrombosis. The volume of the bone flaps was 5.6 cm(3) (range 1 cm(3) to 12 cm(3)). The average follow-up time was 20 months (range 8 to 40 months). All cases resulted in union, and full weight bearing status was achieved at a mean of 23.8 weeks (range 10 to 52 weeks) postoperatively.

CONCLUSIONS

Vascularized bone transfer in the form of the MFC free flap was a valuable method for foot and ankle reconstruction. The MFC flap provided an alternative for those defects that were smaller then 3 cm in length. In our experience, for small bone defects requiring vascularized bone, the MFC flap is currently the ideal donor location supplanting the iliac crest.

LEVEL OF EVIDENCE

Level IV, retrospective case series.