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Distraction subtalar joint fusion using a custom 3D-printed implant

Definition A patient-specific custom 3D–printed porous titanium implant for subtalar joint fusion to restore height, length, and alignment of the hindfoot. Indications Calcaneus malunion/nonunion Subtalar fusion malunion. Anatomy and pathogenesis The subtalar joint is comprised of the talocalcaneal joint and the talocalcaneonavicular joints. The subtalar joint allows for inversion and eversion of the hindfoot but also has a rotational component, allowing the talar head to internally…

Optimization for Total Hip Arthroplasty and Total Knee Arthroplasty

Abstract While total hip arthroplasty and total knee arthroplasty are safe and effective for treating severe hip and knee osteoarthritis, careful identification of patient risk factors and risk mitigation are important steps prior to surgery. Obes… Introduction Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are two of the most common surgical procedures performed in the United States today, with projected yearly case numbers of…

Tibiotalocalcaneal fusion with talar cage for hindfoot reconstruction

Definition Tibiotalocalcaneal (TTC) fusion is a salvage procedure for patients with substantial ankle and subtalar arthritis or severe malalignment of the ankle-hindfoot complex. In many cases, this procedure is the only option available to provide patients with a stable, painless, plantigrade foot for ambulation. General indications for TTC include severe symptomatic hindfoot and ankle deformity or combined ankle and hindfoot arthritis for which nonsurgical management has…

3D-printed solutions for avascular necrosis of the talonavicular joint

Definition Excision of the talus and navicular in total, which is then replaced with a metallic, patient-customized 3D-printed implant. Indications Avascular necrosis (AVN) of the talus and/or the navicular. Comminuted fracture of talus and navicular. Post-traumatic arthritis with poor bone quality and cystic formation. Osteolysis or bone resorption secondary to an infection. Anatomy The talonavicular joint (TNJ) is a ball and socket type of joint that…

Custom constrained 3D total talus/navicular replacement

Definition The utilization of 3D printing technology for combined total talus and navicular replacement with incorporation of subtalar joint fusion and total ankle replacement. Indications Talar avascular necrosis Aseptic talar body collapse Failure of total ankle arthroplasty with talar subsidence/collapse Nonunion of talar fracture following open reduction and internal fixation (ORIF) Failed nonoperative management Patient history and physical exam Detailed patient history must include history of…

Primary total ankle total talus replacement

Definition Surgical treatment of end-stage ankle arthritis with concomitant avascular necrosis (AVN) of the talus utilizing a combination of patient-specific 3D-printed and off-the-shelf (OTS) components for joint preservation and restoration of function. 3D printing has evolved and now allows surgeons to partner with technology that facilitates a continuity of care to maintain ankle joint range of motion (ROM) and avoid the need for tibiotalar calcaneal joint…

3D-printed custom hemi-talus replacement

Definition Resection of damaged cartilage and subchondral bone in the talus which is then replaced with a metallic, patient-specific, 3D-printed implant without the need for malleolar osteotomy. Indication(s) Chronic, medium-to-large osteochondral defects (OCDs) of the talar dome which are often uncontained (i.e., involving the talar shoulder) and have mixed cystic and sclerotic subchondral bone. Prior failed arthroscopic OCD repair which may include debridement, microfracture, or morselized…

Primary constrained total talus with subtalar joint arthrodesis

Definition Patient-specific 3D custom-printed metallic constrained total talus replacement includes modifications to implant design and technique in order to incorporate subtalar arthrodesis. Anatomy The talus, through its articulations, is the link between foot and ankle motion. The talus is covered by approximately 60% cartilage, with little area remaining for soft tissue attachments or penetration of blood supply. , The neck of the talus allows for ligament…

Total talus replacement with a titanium nitride-coated 3D-printed titanium implant

Definition Total talus replacement (TTR) is a surgical procedure which involves the removal of a pathologic talus and replacement with a patient-specific 3D-printed titanium (Ti) prosthesis coated with titanium nitride (TiN). DICOM data from a CT scan is used with specialized software to determine the size and dimensions of a TTR prosthesis. CT scans of bilateral ankles are preferable and recommended; however, data only from a…

Isolated total talus replacement

Definition Excision and replacement of the talus with a patient-specific 3D-printed metallic implant in patients without adjacent joint disease. Indications Avascular necrosis (AVN) of the talus without significant arthritic changes ( Fig. 4.1 ). Complex talus trauma ( Fig. 4.2 ). Large osteochondral lesions with cystic formation which have failed traditional surgical procedures ( Fig. 4.3 ). Malignancy requiring excision of the talus. Anatomy Greater than…

Material science for 3D printing in medicine

Introduction Materials science and 3D printing As discussed in Chapter 1 , materials for 3D printing include polymers, ceramics, metals, and composites. The materials used to fabricate a 3D part are dependent on the performance, or the “requirements” of the final part for its application. Material selection is also dependent on the 3D-printing technology used, as not all materials can be manufactured using all available 3D-printing…

CT to software and other considerations

Introduction To design implants that are personalized to the patient’s anatomy and a specific surgical plan, engineers rely on medical imaging to create accurate anatomical reconstructions. CT image data is commonly required in orthopedic applications due to the volumetric dataset presented and clear contrast of bone, but MRI and X-ray data can also be used in unique cases. There are numerous commercially available software packages that…

Historical perspectives on 3D printing

Introduction 3D printing has changed the landscape of medical devices by accelerating innovation and expanding what is possible to make. Ideas that used to be too expensive or not possible can now be easily 3D printed. Today 3D printing is used for several applications, ranging from toys to complex surgical implants. While 3D printing has been applied to many disciplines, this chapter will focus on concepts…

Emerging Technologies

Introduction New biologic options are being developed throughout the world to enhance existing techniques, offer new off-the-shelf options, and provide reproducible structural repair. I contacted several companies worldwide and asked them to share their core technologies, preclinical development, clinical trial outcomes, and postmarketing surveillance outcomes, as available. The following list is by no means complete but offers a sampling of what potentially may be available to…

Complex Cases in Cartilage Repair: Tricks and Tips

My residents and clinical fellows have often asked me where they can find a well written technique for a medial subvastus exposure as well as the tips and tricks that I use in more complex joint-preserving reconstructions. For this reason I have included a chapter to demonstrate in detail the technique for a medial subvastus exposure and several complex clinical cases that illustrate the principles and…

Meniscal Allograft Transplantation

Introduction Loss of meniscal tissue drastically alters the biomechanical environment of the knee joint, especially in the lateral compartment, where contact stress can increase by 200% to 300% after total meniscectomy. Compartment overload syndrome can ensue, presenting with weight-bearing pain and recurrent effusions. Secondary osteoarthritis is a predictable endpoint, which has led to increased awareness among orthopedic surgeons of meniscal transplantation in cases where subtotal or…

Treatment of Deep Osteochondritis Dissecans Lesions, Avascular Necrosis, and Osteochondral Defects of the Knee Using Autologous Bone Grafting

Introduction The management of an osteochondral defect in the knee is one of the most difficult conditions for the orthopedist. Although a fresh osteochondral allograft seems to be the treatment of choice for this condition, allografts are not without their own problems. A size match may be difficult to obtain and only available in certain parts of the world and resorption and collapse of the allograft…

Patellofemoral Malalignment, Tibial Tubercle Osteotomy, and Trochleoplasty

Introduction This chapter is meant to offer the practicing orthopedist a practical management approach to dealing with patellofemoral disease. The key to successful treatment relies on an accurate diagnosis of the underlying pathomechanics responsible for the pain. Chronic patellofemoral pain is a common and problematic management issue. The term “chondromalacia” has often been applied to anterior knee pain. Chondromalacia (soft cartilage), a pathologic term, may not…

Femoral Varus Osteotomy

Introduction The valgus knee (see Fig. 11.1 ) is usually associated with hypoplasia of the lateral femoral condyle and a superior lateral directed joint line. The ankle joint is frequently obliquely orientated to the floor parallel to the knee joint in this situation. Corrective osteotomy performed at the level of the femoral deformity to restore the joint line parallel to the floor will also make the…