Mechanical Axis Method to Determine First Intermetatarsal Angle and Tibial Sesamoid Position.

Utilizing the mechanical axis can decrease load on the joint and be beneficial when analyzing bony deformities and planning surgical correction with osteotomies. The aim of this study was to identify the normal mechanical axes of the first and second metatarsals and use them to obtain the first/second mechanical intermetatarsal angle (mIMA). The mechanical axis of the first metatarsal was used to obtain the mechanical tibial sesamoid position (mTSP), which provides a mechanical relationship with the sesamoid apparatus. The angular difference between the anatomic and mechanical axis lines (anatomic-mechanical angle [AMA]) was determined for the first metatarsal and for the second metatarsal. The commonly used first/second anatomic intermetatarsal angle (aIMA) and anatomic tibial sesamoid position (aTSP) were also obtained and compared with the first/second mIMA and mTSP. In this retrospective analysis, radiographs of 50 normal feet (40 patients) were assessed. Pearson's correlation coefficients were used to measure reliability between obtained measurements. Mean first/second aIMA was 8.6 ± 3.0 degrees, and first/second mIMA was 8.6 ± 2.6 degrees. First metatarsal AMA was 1.1 ± 1.0 degrees; second metatarsal AMA was 2.0 ± 1.6 degrees. The mTSP was 2.8 ± 1.1, and aTSP was 2.9 ± 1.0. The TSP median was 3 (range, 1-5). Using the mechanical axis method to obtain the first/second mIMA and the mTSP is reproducible and not affected by anatomic changes to the shape of the metatarsal. Unlike the anatomical axis, the mechanical axis does not change, therefore we recommend using the mechanical axis during surgical planning and when obtaining preoperative and postoperative measurements for the long bones of the foot, particularly for forefoot conditions such as hallux valgus.

The Use of Hexapod External Fixation in the Management of Charcot Foot and Ankle Deformities.

Charcot neuroarthropathy (CN) and its sequela is a disabling pathology in the foot and ankle. The 2-stage computer hexapod-assisted technique is an effective tool to address midfoot Charcot and ankle-hindfoot deformities to restore function and decrease the risk of amputation secondary to ulceration and infection. Although this is not the only technique available, it is an excellent option in cases with significant angular deformity or subluxation, need to reduce shortening of the foot, and in the presence of soft tissue defects, with or without concurrent soft tissue or bone infection.

Interobserver Analysis of Standard Foot and Ankle Radiographic Angles.

Standard foot and ankle radiographs have long been studied and averages formulated in an attempt to provide a common framework for understanding the relationships of the foot and ankle, not only for surgical planning but also to determine normal versus abnormal relationships. The authors describe 8 angles measured on 100 patients by up to 18 observers (4 attending physicians, 12 residents, and 2 students). This study validates the previously documented normal angles using a significantly larger observer group as well as a greater number of analyzed angles. Additionally, this study reveals the tibio-second metatarsal angle on the calcaneal axial view is not a reliable radiographic angle for evaluation of foot and ankle deformity. Intraclass correlation coefficients were also analyzed, which displayed variability in measurements based on level of training, with residents being the most accurate, followed by attending physicians and then students. Foot and ankle radiographs are essential for surgical planning, and understanding normal versus abnormal is key before any surgical planning can be accurately performed.

Subchondroplasty: Treatment of Bone Marrow Lesions in the Lower Extremity.

Bone marrow lesions are associated with pain, disease progression, and cartilage loss in inflammatory and noninflammatory conditions, and are related to mechanical loading and subchondral stress. Treatment, particularly in the foot and ankle, is challenging. In the subchondroplasty procedure, flowable, synthetic, calcium phosphate bone filler is injected into the defect region, improving subchondral bone integrity and allowing remodeling back into healthy cancellous bone. The procedure is a promising treatment option for bone marrow lesions, particularly in the foot and ankle. The benefits are a minimally invasive procedure with early return to weightbearing.

Minimally Invasive Bunion Correction.

Hallux valgus is a common condition that results in lateral deviation of the hallux and medial deviation of the metatarsal. When conservative management fails, surgical management is often necessary. More than 150 procedures have been described, and most recommend an open approach. More recently, a minimally invasive approach to bunion correction has gained popularity among surgeons. The authors have been performing a minimally invasive percutaneous method of bunion correction with positive outcomes. This article presents case examples and a systematic approach for correction of this common foot condition.

3D Printed Total Talar Replacement: A Promising Treatment Option for Advanced Arthritis, Avascular Osteonecrosis, and Osteomyelitis of the Ankle.

Advanced ankle arthritis, avascular osteonecrosis, and osteomyelitis of the ankle remain a surgical challenge in the foot and ankle arena with limited treatment options. Multiple medical comorbidities contribute to total loss of the talus. Collapse of the talar body as a complication of total ankle arthroplasty, talectomy in infection, and septic talus necrosis or severe bone defects caused by tumor resection may result in need for total talar replacement. Ankle arthrodesis and tibiocalcaneal fusion after talectomy can produce severe disability of the ankle and foot. Total ankle replacement is a viable option for treatment of end-stage ankle arthritis in appropriate patient populations.

The Gradual and Acute Correction of Equinus Using External Fixation.

Equinus is one of the most common deformities noted in foot and ankle biomechanics that, at times, if not identified and managed properly may lead to significant lower extremity pathology. With that being said, this deformity is also one that may be both underdiagnosed and undertreated. Treatment for equinus can range from conservative therapy to more aggressive surgical therapy. The purpose of this article is to review the clinical workup to properly identify the deformity and to explore the various treatment options for its timely management, which include gradual or acute correction of equinus using external fixation.

Lengthen, Alignment, and Beam Technique for Midfoot Charcot Neuroarthropathy.

Charcot neuroarthropathy is a disabling pathology in the foot and ankle. Midfoot Charcot is most common and results in progressive deformity. We describe a 2-step approach to surgical reconstruction, referred to as the lengthen, alignment, and beam technique. There is an initial surgery involving acute equinus correction through Achilles tendon lengthening and gradual correction with hexapod external fixation to align the deformity, followed by minimally invasive medial and lateral column beaming. This surgical protocol allows for adequate reduction of deformity. The second stage allows for rigid intramedullary fixation extending beyond the pathologic joints via a minimally invasive technique.

Midfoot Charcot Reconstruction.

Midfoot Charcot joints are complex problems that are most commonly seen in patients with peripheral neuropathy secondary to diabetes. The goal of management is to prevent pedal collapse, which can lead to ulceration; infection; and in some cases, amputation. Principles of surgical management should be centered on respecting the soft tissue, obtaining correction, maintaining correction, and supplementing with orthobiologics to achieve healing. The authors present strategies, case examples, and tips and tricks to treat this complex condition with external and internal fixation.

The Evolution of Limb Deformity: What Has Changed over the Past Ten Years?

Limb deformity correction has been widely discussed in orthopedic literature with an increasing interest in technologically based surgical strategies. However, principles described by Ilizarov and Paley still form the basis of these newly developing surgical systems. The recent advances and increased use of computers and mobile devices in the medical arena, along with the application of dynamic hexapod external fixation, have allowed for easier and more convenient strategies, leading to a greater outreach and more confidence in the newer surgeon when faced with addressing a patient with a limb deformity.

Guided Growth With Temporary Hemiepiphysiodesis to Treat Ankle Valgus in a Skeletally Immature Individual: A Case Report.

Guided growth is useful in correcting pediatric angular deformities. Ankle valgus is a coronal plane deformity and is often seen in skeletally immature patients with congenital or acquired lower extremity pathologic features. Temporary hemiepiphysiodesis with a percutaneous transphyseal medial malleolar screw is a surgical treatment capable of correcting the angular deformity and can offer effective correction. In the present case study, a 12-year-old male with dorsal-lateral peritalar subluxation and ankle valgus underwent a reconstructive procedure and temporary hemiepiphysiodesis with a percutaneous medial malleolar screw. After removal of the screw, reduction of his peritalar subluxation was achieved, improving his lateral-distal tibial angle from 81° preoperatively to 89° at the final follow-up examination. The patient returned to his preoperative sporting activities and ambulated comfortably and pain free in sneakers with orthotics. In conclusion, temporary hemiepiphysiodesis with a transphyseal medial malleolar screw is an effective treatment option for ankle valgus in a skeletally immature individual.

The Mechanical Axis of the First Ray: A Radiographic Assessment in Hallux Abducto Valgus Evaluation.

The present report describes a new method of hallux abducto valgus deformity correction planning using the mechanical axis of the medial column (mechanical axis planning). This method of radiographic evaluation identifies an ideal position for the first metatarsal after correction and is useful regardless of the surgical procedure chosen. We retrospectively reviewed 200 radiographs to identify a "normal" value for the mechanical axis angle. We reviewed 100 radiographs of patients with hallux abducto valgus deformity (deformity group) and 100 radiographs of patients without hallux abducto valgus deformity (control group). The deformity group revealed an M1-M2 anatomic axis angle of 13.5° ± 2.83° and an M1-M2 mechanical axis angle of 11.58° ± 1°. The control group revealed an M1-M2 anatomic axis angle of 7.5° ± 1.76° and an M1-M2 mechanical axis angle of 11.19° ± 0.9°. The differences in the M1-M2 anatomic axis angle and M1-M2 mechanical axis angle were statistically significant between the control and deformity groups. We sought to provide a reliable method for planning hallux abducto valgus deformity correction by aligning the mechanical axis of the medial column and the mechanical axis of the first ray to the "normal" value of 11° to reduce the deformity.

Medial Column Arthrodesis Using an Anatomic Distal Fibular Locking Plate.

The medial column fusion is performed for a multitude of etiologies, including peritalar subluxation deformity, Charcot arthropathy, trauma, post-traumatic degenerative joint disease, and rheumatoid arthritis. Various surgical techniques have been described for medial column arthrodesis. We describe a new fixation method using an anatomic distal fibular locking plate for medial column arthrodesis. This technique provides a rigid construct in compromised or at risk bone. After a review of the surgical technique, we outline 2 case examples of patients with peritalar subluxation and Charcot arthropathy.

Tibiocalcaneal arthrodesis in the high-risk foot.

The present case series outlines the history and surgical treatment of 6 patients who underwent tibiocalcaneal arthrodesis from April 2002 to May 2012, all with external fixation as the primary or secondary fixation. Surgical intervention was performed by the same surgeon at the same facility. The indication for surgery was a nonbraceable Charcot deformity in 5 (83.3%) patients and bone and soft tissue infection complicating previous intramedullary hindfoot fusion in 1 (16.7%) patient. Talectomy was performed in 2 (33.3%) patients secondary to widespread osteomyelitis of the talus and in 4 (66.7%) patients secondary to avascular necrosis and/or disintegration and fragmentation of the remaining talus. The postoperative complications have been discussed in detail and their management outlined. At the most recent follow-up visit, all patients were independently ambulating on a braceable limb with or without the use of an assistive device. In conclusion, tibiocalcaneal arthrodesis is a reasonable option for limb salvage to produce community ambulators in the high-risk population. We emphasize that although multiple fixation options are available for tibiocalcaneal arthrodesis, a combination of internal and external fixation is vital to its success.