51 Hintegra Total Ankle System Abstract The Hintegra ankle is a three-component ankle that uses a flat, 4-mm-thick loading plate with six pyramidal peaks for full coverage of resection surface of tibia. The talar component is anatomically shaped with a conical form with a smaller radius medially rather than laterally. It has two 2.5-mm rims on the medial and lateral sides which ensure stable position of the polyethylene insert. The insert is available with the thickness of 5 to 9 mm. Given the parallelism of the two interfaces, the Hintegra ankle does provide, in contrast to other current ankles, intrinsic stability in the frontal plane. Its unique design permits to use the Hintegra ankle as a part of hindfoot reconstruction, which may also include correcting osteotomies above and below the ankle, fusion of periarticular joints, ligament reconstructions, and tendon transfers. It also allows to revise a failed ankle arthrodesis to total ankle replacement. With the available revision components with thicker tibial platform and flat talar undersurface, respectively, the Hintegra ankle also enables the surgeon to manage bone defects, as typically encountered in revision of failed component. Conceptor and nonconceptor studies have proven effectiveness of the Hintegra ankle in the clinical use with a survivor-ship of 86 to 93% at 10 years. Keywords: total ankle replacement, Hintegra ankle, surgical technique, indication, contraindication, design, revision arthroplasty • In the past decade, total ankle replacement has evolved to a valuable alternative to arthrodesis for end-stage osteoarthritis of the ankle. • The Hintegra ankle is composed of three components and was introduced in 2000 to the market (not yet approved by the Food and Drug Administration for U.S. market). • Numerous studies have reported very satisfactory outcomes with a survivorship of 86 to 93% at 1 year. • Primary and secondary end-stage osteoarthritis of the ankle. • Salvage of failed ankles. • Salvage for failed ankle fusions. • Low and moderate demands for sports. • Associated hindfoot or midfoot arthritis, bilateral ankle arthritis. • Patient not wanting an ankle fusion. While the patient is standing, perform a thorough clinical investigation of both lower extremities to assess • Alignment. • Deformities. • Foot position. • Muscular atrophy. While the patient is sitting with free-hanging feet, perform an assessment of • Extent to which a present deformity is correctable. • Preserved joint motion at the ankle and subtalar joints. • Ligament stability of the ankle and subtalar joints with anterior drawer and tilt tests. • Supination and eversion power (e.g., function of posterior tibial and peroneus brevis muscles). • Standard weight-bearing X-rays including alignment view (Fig. 51.1). • CT scan to assess bone stock. • SPECT-CT to assess neighboring joints. • MRI to assess vascularity. • Brace immobilization. • Activity modification. • Rocker bottom sole and cushioned heel to shoe; orthotic inserts. • Medications: cortisone injection, hyaluronic acid injections, anti-inflammatory medications. • Severe osteoporosis. • Immunosuppressive therapy. • Increased demands for physical activities (e.g., jogging, tennis, downhill skiing). • Infection. • Avascular necrosis of more than one-third of surface at either talar or tibial side. • Nonmanageable instability/misalignment. • Neuromuscular disorders. • Charcot neuroarthropathy. • Metal allergy or intolerance. • Highest demands for sports. • To replace the worn-out articular surfaces of tibia and talus with minimal bone resection. • To restore mechanics of the ankle as closely as possible. • To mimic physiologic load transfer at bone–implant interface and thus ensure for long-term stability of components. Fig. 51.1 Standard weight-bearing radiographs including (a) AP view of the ankle, (b) lateral view of the foot and ankle, (c) AP view of the foot, and (d) Saltzman hindfoot alignment view. • Simple and reliable instrumentation. • Nonconstrained three-component device. • Includes revision implants. • Anterior approach to the ankle. • Mounting and adjusting tibial resection bloc, tibial cut. • Step-by-step talar resection. • Debridement of medial, lateral, and posterior gutters. • Insertion of implants: • Additional procedures, if necessary: • Wound closure. • Design of tibial component: Fig. 51.2 (a) The Hintegra ankle (anterior view): the tibial component—(b) medial view and (c) plantar view—has an anatomic shape to fit to fully cover the resection surface and to get support on circumferential cortex; the talar component—(d) dorsomedial view and (e) dorsoplantar view—has a conical form with medially a smaller curvature; and the polyethylene insert—(f) anterior view. • Design of talar component: • Design of polyethylene insert: • Resurfacing alone: • Minimal thickness: • The superior extensor retinaculum is a thickening of the deep fascia above the ankle, running from the tibia to the fibula including the tendons of the tibialis anterior, extensor hallucis longus, and extensor digitorum longus. • The anterior neurovascular bundle lies consistently between the extensor hallucis longus and extensor digitorum longus tendons. • The neurovascular bundle contains the tibialis anterior and the deep peroneal nerve. • The patient is positioned with the feet on the edge of the table. • The ipsilateral back is lifted until a strictly upward position of the foot is obtained. • The tourniquet is mounted at the ipsilateral thigh. • An anterior longitudinal incision of 10 to 12 cm in length is made to expose the retinaculum. • The retinaculum is incised along the lateral border of the anterior tibial tendon. • The distal tibia is exposed, and arthrotomy is made. • Loose bodies and osteophytes are removed. • The Hintermann distractor is mounted on anteromedial side to distract the ankle joint (Fig. 51.3a). • The tibial cutting block with its alignment rod is positioned using the tibial tuberosity as the proximal reference, and the anterolateral border of the ankle as the distal reference. • The final adjustment is made as follows: • The tibial cutting guide is slid into the cutting block, creating a slot in which the saw blade will be guided. The width of the slot limits the excursion of the saw blade, thereby protecting the malleoli from being hit and fractured. • Tibial cut is done with an oscillating saw. • The talar resection block is inserted into the tibial cutting block. • The resection block is moved distally as much as possible to properly tension the collateral ligaments. • While the foot is held in neutral position, the resection block is fixed by two pins. • Talar cut is done with an oscillating saw. • The 12-mm-thick spacer, representing the thickness of the tibial and talar components and the thinnest 5-mm inlay, is inserted into the created joint space. While the foot is held in neutral flexion position, the surgeon should check (Fig. 51.3d): • The spacer is removed and the Hintermann distractor mounted using the same pins.
51.1 Introduction
51.2 Indications
51.2.1 Clinical Evaluation
51.2.2 Radiographic Evaluation
51.2.3 Nonoperative Options
51.2.4 Contraindications
Relative
Absolute
51.3 Goals of Surgical Procedure
51.4 Advantages of Surgical Procedure
51.5 Key Principles
Talar component.
Tibial component.
Polyethylene insert.
To align the ankle joint complex.
To stabilize the ankle joint complex.
51.6 Preoperative Preparation and Patient Positioning
51.6.1 The Device (Fig. 51.2)
Maximal contact area.
Anatomically shaped
Guides the polyethylene insert
Covers talus completely.
Optimal force distribution.
Minimal deformation forces.
Minimal bone resection.
Minimal disturbance of vascularity.
No stress shielding.
Minimal stress forces.
Minimal dislocation.
51.6.2 Anatomy
51.6.3 Positioning
51.7 Operative Technique
51.7.1 Exposure
51.7.2 Tibial Resection (Fig. 51.3b, c)
Sagittal plane: The rod is moved until a position parallel to the anterior border of the tibia has been achieved.
Frontal (coronal) plane: After preliminary fixation of the block with a long pin, the tibial resection block is rotated until proper varus/valgus alignment and ligament tension have been achieved.
Vertical adjustment: The tibial resection block is moved proximally until the desired resection height is achieved. Usually, resection of approximately 2 mm on the apex of the tibial plafond is desired.
51.7.3 Talar Resection
If an appropriate amount of bone has been resected.
If the achieved alignment is appropriate (Fig. 51.3e).
If the medial stability and lateral stability are appropriate.
Musculoskeletal Key
Fastest Musculoskeletal Insight Engine
Physiological load transfer.
