Electrical bone stimulation: an overview and its use in high risk and Charcot foot and ankle reconstructions

Since early work done in the 1950s on the "piezoelectricity of bone," a growing body of basic science and clinical evidence suggests the use of electrical bone stimulation as an adjunct in the treatment of foot and ankle nonunions, fusions, and Charcot arthropathy. Both implantable designs (that allow for direct constant stimulation of bone) and nonimplantable (such as pulsed and combined electromagnetic fields) devices have been studied. Ongoing research continues to support the potential usefulness of these modalities.

Implantable electrical bone stimulation for arthrodeses of the foot and ankle in high-risk patients: a multicenter study

This study assessed arthrodesis procedures performed in the foot and ankle of high-risk patients following implantation of an internal electrical bone stimulator. Criteria defining patients as "high risk" included diabetes, obesity, habitual tobacco and/or alcohol use, immunosuppressive therapy, and previous history of nonunion. Standard arthrodesis protocol of bone graft and internal fixation was supplemented with the implantable electrical bone stimulator. A retrospective, multicenter review was conducted of 26 patients (28 cases) who underwent 28 forefoot and hindfoot arthrodeses from 1998 to 2002. Complete fusion was defined as bony trabeculation across the joint, lack of motion across the joint, maintenance of hardware/fixation, and absence of radiographic signs of nonunion or pseudoarthrosis. Radiographic consolidation was achieved in 24 of the 28 cases at an average 10.3+/-4.0 weeks. Followup averaged 27.2 months. Complications included 2 patients who sustained breakage of the cables to the bone stimulator. Five patients underwent additional surgery. Four of the 5 patients had additional surgery in order to achieve arthrodesis. All 4 went on to subsequent arthrodesis. This study demonstrates how arthrodesis of the foot and ankle may be enhanced by the use of implantable electrical bone stimulation.

Demineralized bone matrix: basic science and clinical applications

Bone grafting with demineralized bone matrix (DBM) is useful in reconstructive surgery to ultimately provide anatomic alignment, restore function, or augment/change the biomechanics of the foot and ankle. DBM should be used in conjunction with a transplant or implant displaying mechanical strength. DBM can augment cortical grafts used for bridging gaps or defects and lengthening procedures by increasing the connectivity of the structural graft with the host bone. Another useful application is providing a biologic boost to patients who have less-than-ideal physiology. Because DBM has higher concentrations of available bone morphogenic proteins, it can aid in the incorporation of other grafts. Other uses include delayed unions, nonunions, packing joints for arthrodesis, filling resected cysts, and filling gaps of debrided infected bone.

Die modifizierte Lapidus-Arthrodese

For the correction of hallux valgus, as one of the most common deformities of the lower limbs, a modified Lapidus arthrodesis is applied at the base of the hallux. After using a lateral tissue technique with medial capsular reefing, a general arthrodesis of the tarsometatarsal 1 joint is carried out. An unstable hallux is the indication for a classic Lapidus arthrodesis. Before determination of the indication, an exact clinical x-ray examination should be made in the dorsoplanar position as well as laterally standing. Complications associated with the Lapidus arthrodesis are postoperative metatarsalgia and pseudoarthrosis. Advantages of this technique are, for example, a high correction potential and better healing, although the surgical technique and post-operative care are more time consuming than for other methods.

Dorsal modified calcaneal plate for extensive midfoot arthrodesis

BACKGROUND

Extensive midfoot fusions can be challenging because of bone loss, deformity, and soft tissue anatomy. Several options have been advocated, including multiple screw fixation, medial plating, and plantar plating. We report a new technique using a dorsally-placed, modified calcaneal plate for treatment of this difficult clinical problem.

METHODS

Patients undergoing extensive (more than four joints) midfoot arthrodeses with a dorsally-placed, modified calcaneal plate between 2000 and 2003 were retrospectively reviewed. Diagnoses included Charcot arthropathy (four), osteoarthritis (two), posttraumatic osteoarthritis (two), massive bone loss from previous infection (one), and residual clubfoot deformity (one). Patients with active midfoot infections were excluded. During the study period, midfoot arthrodeses with a dorsal calcaneal plate were done in 10 patients. Of these, nine patients were available for review. Arthrodeses were attempted in 62 joints in these nine patients. Autogenous grafting was used in three patients (23 joints), allograft was used in six patients (39 joints). Patients were maintained nonweightbearing until radiographs or computed tomography conclusively showed union.

RESULTS

One of the 10 patients died from an unrelated cause. In the nine remaining patents, 95% (59 of 62) of joints fused within 4 months of surgery. Postoperative complications included nonunion with broken screws in one patient, and three wound problems successfully treated with local dressings. Secondary procedures included one revision arthrodesis and two hardware removals. Patient satisfaction with this procedure was very high (eight of nine).

CONCLUSIONS

The use of a dorsal calcaneal plate is a viable method of fixation for achieving fusion in extensive midfoot arthropathy. The plate is low-profile and easily moldable to conform to dorsal midfoot anatomy. It can be placed without extensive plantar or medial foot dissection and maintains midfoot alignment until bony fusion occurs. In patients with complex midfoot pathology requiring multijoint fusions, the results have been satisfactory.

Plantar pressures in the forefoot after lateral column lengthening: a cadaver study comparing the Evans osteotomy and calcaneocuboid fusion

BACKGROUND

Excessive varus alignment of the forefoot after lateral column lengthening has been reported to lead to overloading of the lateral foot. The purpose of this study was to investigate whether there is a difference between the Evans opening wedge calcaneal osteotomy (Evans) and the calcaneocuboid distraction arthrodesis (CCDA) with respect to lateral forefoot loading.

METHODS

In each of 12 matched pairs of cadaver feet, plantar pressure measurements of the intact specimens were obtained during simulated foot-flat and early heel-rise phases of gait and again after randomly performing the Evans procedure on one foot and the CCDA on the other foot. Cervical plate fixation was used for immediate stability.

RESULTS

Both procedures resulted in statistically significant increased loading of the lateral forefoot and decreased loading of the medial forefoot compared with the preoperative status. The relative increase in lateral pressures was statistically greater with the CCDA than with the Evans. The average increase in pressure under the fifth metatarsal head in the foot-flat phase was 46% +/- 42% (range-4% to 141%) with the Evans and 104% +/- 58% (range 9% to 216%) with the CCDA (p = 0.003). In the early heel-rise phase, the increase in pressure was 50% +/- 43% (range 2% to 108%) and 96% +/- 65% (range 12% to 263%), respectively (p = 0.02).

CONCLUSION

The experimental data suggest that lateral column overload may be more likely with the CCDA than with the Evans. Physicians should be aware of the likelihood of increasing lateral column loads with both the CCDA and the Evans procedure. It may be possible to avoid this problem by using less lateral column lengthening than the 1 cm used in this study or by considering a medial column arthrodesis or plantarflexion osteotomy to balance forefoot loading.

Realignment arthrodesis of the rearfoot and ankle: a comprehensive evaluation

Ankle and tibiotalocalcaneal arthrodeses are performed for the treatment of painful, arthritic, unstable, and deformed rearfoot and ankle joints. Surgical complications are not uncommon (approximately 30%); some can be attributed to poor preoperative planning and inadequate intraoperative position. Several authors have attempted to define the optimal position for ankle arthrodesis without objective multiplanar radiographic analysis and consistent reference points. This investigation explored the effects of ankle and tibiotalocalcaneal realignment arthrodeses on static lower-extremity position in 20 patients. The most common preoperative diagnosis was severe degenerative joint disease following ankle fractures and ankle instability. Seven tibiotalocalcaneal arthrodeses and 13 isolated ankle arthrodeses were performed (mean follow-up, 22 months). Average time to radiographic osseous union of the isolated ankle and tibiotalocalcaneal arthrodeses was 11 and 7 weeks, respectively. Medical complications occurred in 2 patients (10%). There were no statistically significant differences between preoperative and postoperative angular relationships. This study objectively quantifies multiplanar foot-to-leg realignment and defines the optimal clinical and radiographic positions for ankle and tibiotalocalcaneal realignment arthrodeses.

A systematic approach to evaluation of the rearfoot, ankle, and leg in reconstructive surgery

The current literature shows that proper alignment of the lower extremity allows for greater function throughout the gait cycle. Therefore, realignment should be one of the primary goals in the surgical management of lower-extremity deformities and pathology. Multiplanar radiographic angular relationships should be critically evaluated to appropriately identify the level and extent of the deformity before performing realignment procedures. This article describes a systematic approach to deformity evaluation through a comprehensive radiographic assessment of the rearfoot, ankle, and lower leg.

A cholesterol-containing foreign body granuloma presenting as an inter-metatarsal bursa

A 68-year-old man presented with progressive forefoot swelling which coincided with the onset of type 2 diabetes mellitus. Imaging revealed a cystic inter-metatarsal mass containing two foreign bodies, which had been present for many years. Following aspiration of the mass, cholesterol crystals were observed on polarised microscopy. It is postulated that the development of diabetes triggered the shedding of cholesterol crystals around a long-standing quiescent foreign body granuloma.

Hypermobility of the first tarsometatarsal joint

This article discusses hypermobility of the first tarsometatarsal joint.

Anatomy, biomechanics, and surgical approach to synovial folds within the joints of the foot

The presence of synovial folds in various joints of the foot has been previously documented. The function and clinical significance of these structures within the joint have not been established. Histologically they are considered anatomically different from a meniscus primarily owing to their makeup of loose connective tissue with nerve fibrils and several synovial cell layers. We hypothesize that the function of these folds is similar to that of the menisci: to increase joint congruity and stability. We further hypothesize that these folds will be present in joints of the foot that require greater stability. To demonstrate this, 41 fixated cadaveric feet were sectioned in the sagittal plane and the incidence and locations of the synovial folds were documented. Three fixated cadaveric feet were evaluated using a materials testing machine. The first metatarsophalangeal joint was incised, and the presence of the synovial fold was documented. The joint was then taken through its range of motion with and without the synovial fold while data on the force and displacement were collected. The steps were then repeated for the ankle joint. The results showed statistically stiffer ankle and first metatarsophalangeal joints with the synovial fold present, as determined by the stress-strain curve. On the basis of the presence and location of these synovial folds, we demonstrated arthroscopic surgical approaches to many of the documented joints that contain these folds. Because the folds contain synovial cells and vascular tissue, damage to them can result in considerable pain. In such cases, arthroscopic surgery would be of benefit. Further research may indicate whether they need to be salvaged during joint procedures to facilitate normal joint function or should be removed to reduce postoperative complications.

Current topics review: Charcot neuroarthropathy of the foot and ankle

Charcot arthropathy is a destructive process, most commonly affecting joints of the foot and ankle in diabetics with peripheral neuropathy. Affected individuals present with swelling, warmth, and erythema, often without history of trauma. Bony fragmentation, fracture, and dislocation progress to foot deformity, bony prominence, and instability. This often causes ulceration and deep infection that may necessitate amputation. Instability or deformity may limit the ability to use standard footwear. Treatment is focused on providing a stable and plantigrade foot for functional ambulation with accommodative footwear and orthoses. Historically, treatment had included nonweightbearing immobilization for the acute phase, and surgery had been reserved only for infection, unresolved skin ulceration, or deformity that precluded the use of therapeutic footwear. Current controversies include weightbearing in the acute or reparative phases and early surgical stabilization. Foot-specific patient education and continued periodic monitoring may reduce the morbidity and associated expense of treating the complications of this disorder and may improve the quality of life in this complex patient population.

[Rare dislocations of feet joints--the results of treatment and rehabilitation]

The authors present rare dislocations of feet joints including subtalar dislocations of the foot, total dislocations of the talus, dislocations of the talocalcaneal joint and dislocations of the talo-crural and tarsometatarsal joint. They make objective and subjective assessment of remote results of their non-operational treatment. They also pay attention to dangers and remote after-efects of shown feet injuries.

A review of rheumatoid arthritis affecting the foot and ankle

Rheumatoid arthritis is a systemic disease that often affects the foot and ankle. Approximately 20% of patients with rheumatoid arthritis present initially with foot and ankle symptoms, and most patients will eventually develop foot and ankle symptoms. Although early intervention includes conservative measures, operative treatment often is needed to adequately treat rheumatoid patients. Treatment of foot and ankle problems in patients with rheumatoid arthritis is directed to maintaining ambulatory capacity. This article reviews the clinical presentation, evaluation, and treatment of rheumatoid arthritis affecting the foot and ankle.

Clinical biomechanics of the peritalar joint

The peritalar joint includes the articulations between the talus and calcaneus and the talus and navicular. Motion between the talus and calcaneus is described most often as rotation about an axis that points medially, anteriorly, and superiorly. This motion is considered to be triplanar, with inversion, plantar flexion, and adduction occurring together, whereas eversion, dorsiflexion, and abduction are associated. Similar motions have been described between the talus and navicular. Foot deformity, such as a pes planus or a pes cavus foot type, and hindfoot or midfoot joint fusion can alter the biomechanics of the peritalar joint.

Displaced intraarticular calcaneal fractures: long-term outcome in women

BACKGROUND

This study compared the outcomes of displaced intraarticular calcaneal fractures in women treated operatively or nonoperatively. This was part of a prospective, randomized, controlled, multi-center, clinical trial performed at four level I trauma hospitals. In addition, we compared the long-term outcomes in women with those reported in men in an earlier study.

METHODS

Forty-one women (43 fractures) required treatment for displaced intraarticular calcaneal fractures. Patients' ages ranged from 17 to 65 years at the time of injury. All fractures were closed injuries and had posterior facet displacement of more than 2 mm. Patients were randomly assigned to either the nonoperatively or operatively treated groups. Nonoperative treatment included ice and elevation, while operative treatment consisted of open reduction and internal fixation using a standard lateral approach. Outcomes were measured using the validated Short Form-36 Health Survey (SF-36) and the Visual Analogue Scale (VAS).

RESULTS

Women were 3.18 times (RR 3.18, 95% CI 1.03- 9.79) more likely to report high SF-36 scores after operative treatment than those who received nonoperative treatment. Operative outcomes in women were better than those reported in an earlier study in men (SF-36: 77.47 in women compared to 67.56 in men, p = .07; VAS: 81.47 in women compared to 67.04 in men, p = .01). In women the fractures generally were caused by low-energy trauma that produced less severe injuries (higher Bohler angles). Most patients were not receiving Workman's Compensation benefits and did light to moderate work.

CONCLUSION

Operative treatment of the fractures showed statistically significant better results when compared to nonoperative treatment (SF-36: p = .04; VAS: p = .10) in women. Displaced intraarticular calcaneal fractures in women should be treated by open reduction and internal fixation through a lateral approach.

PEMF as treatment for delayed healing of foot and ankle arthrodesis

BACKGROUND

Arthrodesis is the most common surgical treatment for foot and ankle arthritis. In adults, these procedures are associated with a 5% to 10% rate of nonunion. Pulsed electromagnetic field (PEMF) stimulation was approved by the Federal Drug Administration (FDA) for treatment of delayed unions after long-bone fractures and joint arthrodesis. The purpose of this study was to examine the results of PEMF treatment for delayed healing after foot and ankle arthrodesis.

METHODS

Three hundred and thirty-four foot and ankle arthrodeses were done. Nineteen resulted in delayed unions that were treated with a protocol of immobilization, limited weightbearing, and PEMF stimulation for a median of 7 (range 5 to 27) months. All patients were followed clinically and radiographically.

RESULTS

The use of PEMF, immobilization, and limited weightbearing to treat delayed union after foot and ankle arthrodesis was successful in 5 of 19 (26%) patients. Of the other 14 patients with nonunions, nine had revision surgery with autogenous grafting, continued immobilization, and PEMF stimulation. Seven of these eventually healed at a median of 5.5 (range 2 to 26) months and two did not heal. One patient had a below-knee amputation, and four refused further treatment.

CONCLUSIONS

The protocol of PEMF, immobilization, and limited weightbearing had a relatively low success rate in this group of patients. We no longer use this protocol alone to treat delayed union after foot and ankle arthrodesis.

External fixation techniques for foot and ankle fusions

External fixation in arthrodesis of the midfoot offers a versatile alternative when internal fixation is contraindicated or impossible. Most often, the small wire fixator, such as the Ilizarov device, provides the stability that is necessary to achieve solid union. External fixation allows for continual compression and the ability to produce gradual deformity correction, if necessary.

Fusion in posttraumatic foot and ankle reconstruction

Despite appropriate acute treatment, many foot and ankle injuries result in posttraumatic arthritis. Arthrodesis remains the mainstay of treatment of end-stage arthritis of the foot and ankle. An understanding of the biomechanics of the foot and ankle, particularly which joints are most responsible for optimal function of the foot, can help guide reconstructive efforts. A careful history and physical examination, appropriate radiographs, and, when necessary, differential selective anesthetic blocks help limit fusion to only those joints that are causing pain. Compression fixation, when possible, remains the treatment of choice. When bone defects are present, however, neutralization fixation may be necessary to prevent a secondary deformity that could result from impaction into a bone defect.

Stabilization of Lisfranc joint injuries: a biomechanical study

BACKGROUND

Lisfranc joint injuries are often misdiagnosed, leading to significant morbidity. Methods for anatomic reduction of the tarsometatarsal joint include closed reduction with casting or surgical stabilization with either Kirschner wires and/or cortical screw fixation. Controversy exists as to which fixation technique offers optimal stability. In the present study, the biomechanical stability of three fixation methods was tested: (1) four Kirschner wires, (2) three cortical screws plus two Kirschner wires, and (3) five cortical screws.

METHODS

Ten matched pairs of fresh-frozen cadaveric feet were dissected to their ligamentous and capsular elements. The tarsometatarsal ligaments were completely transected to replicate a Lisfranc dislocation; the "injury" was reduced and stabilized using one of the three methods. Biomechanical studies were performed by applying a 100-N cyclic load physiologically distributed to the plantar aspect of the metatarsal heads. Displacement and force measurements were taken from the first and fifth metatarsal heads. Average stiffness of each construct was calculated from the force displacement curves.

RESULTS AND CONCLUSIONS

Method 2 provided significantly more stability than Kirschner wire fixation. Method 3 created more stiffness than method 2 at the medial portion of the foot; no statistical difference between the two methods was evident at the lateral foot.

CLINICAL RELEVANCE

Cortical screw fixation provides a more rigid and stable method of fixation for Lisfranc injuries as compared to Kirschner wire fixation. This fixation method allows maintenance of anatomic reduction and possibly earlier mobilization with a decreased risk of posttraumatic arthrosis.

Revision arthrodesis of the foot and ankle

Previously failed procedures with less than optimal outcomes always are distressing to the patient and surgeon. The revisional arthrodesis may require a higher level of surgical technique and skill than the original procedure from which it was derived. Another level of difficulty is added when the original procedure was deemed to have failed secondary to poor patient compliance. The basic tenets of successful revisional arthrodesis include a motivated and educated patient, adherence to basic surgical principles and techniques, and the ability to extrapolate those principles and techniques into ideas that are born from thinking along the lines of necessity.

Arthrodesis of the Charcot foot and ankle

The unstable Charcot foot remains a challenge to even the most experienced surgeon. Reconstructive surgical management of the neuropathic Charcot foot is a valuable treatment option for the patient who has severe musculoskeletal deformity. Frequently, the unstable nature of this deformity prevents successful use of therapeutic shoes or braces. For these high-risk individuals, reconstructive surgery often is the only way to avoid amputation. With precise surgical technique, appropriate postoperative care, and meticulous patient compliance, stability can be restored to the dysfunctional foot. The management of the Charcot foot can be extremely rewarding for the patient and surgeon.

Land mine injury: functional testing outcome

We present a case of a war patient treated with external fixation for a complex land mine injury involving the fracture of the tibial and fibular bones, which occurred at the front line during the war in Croatia and Bosnia and Herzegovina. Excessive destruction and foreign body penetration into the distal two-thirds of the right leg and foot endangered not only the patient's lower extremity but his life as well. Nevertheless, the patient's life, as well as extremity, was saved due to an intensive treatment. A 100-month follow-up showed a bridge callus between the tibia and fibula, tibial bone defects, tibial anterior angulation of 5 degrees, and arthrosis of the right upper ankle joint. Despite a relatively unsatisfactory X-ray finding, the functional testing on the dynamometry system Cybex 300 showed surprisingly good results. There was a satisfactory functional recovery of the treated extremity: the patient could walk without any help even on rocky grounds and was actively involved in his sheep farm duties.