A P P E N D I X   2

Orthopedic Devices

Angela Gopez and Aaron Cho

PLATES AND SCREWS

Blade Plate and Screws

  • Seen with subtrochanteric and supracondylar femoral fractures (Fig. A2-1) as well as femoral osteotomies

  • Angled plate configuration

    Reconstruction Plate

  • Commonly used for pelvic (Fig. A2-2) and calcaneal (Fig. A2-3) fractures

  • Malleable plate that can be appropriately sized and configured for stabilization of fractures with complex bony surfaces

    FIGURE A2-1 Blade plate and screws stabilizing bilateral proximal femoral varus osteotomies.

    FIGURE A2-2 Reconstruction plate and screws fixating an acetabular fracture.

    FIGURE A2-3 Reconstruction plate and screws stabilizing calcaneal fracture.

    Buttress Plate and Screws

  • Also known as periarticular plates

  • Commonly used for stabilization of periarticular fractures, particularly at the distal radius, femur, tibia, and proximal humerus

  • Varying plate designs with names often dependent on plate configuration, such as T-plate (Fig. A2-4) and L-plate

    FIGURE A2-4 T-shaped buttress plate stabilizing distal radial fracture, in splint.

    FIGURE A2-5 Cortical screw with washer stabilizing prior patellar tracking realignment surgery. Incidentally noted is the presence of a nonossifying fibroma within the distal femoral metaphysis.

  • Support bone unstable in compression or axial loading by holding impacted and depressed fragments in position, which is enhanced by the elongated contour of the plate as it approaches the articular surface

    SCREWS

    Cortical Screws

  • As is implied in the name, utilized for stabilization of cortical bone and thus usually placed across the near and far cortex of bone (Fig. A2-5)

  • Have shallower threads and narrower thread pitch compared with cancellous screws

    Cancellous Screws

  • Most commonly used in the metaphyses of long bones (Fig. A2-6)

  • Threads more widely spaced and generally deeper compared with cancellous screws

    Cannulated Screws

  • Cannulated cancellous screws commonly used for metaphyseal fractures; cannulated cortical screws utilized as lag screws for diaphyseal fractures (Fig. A2-7)

    FIGURE A2-6 Cancellous screw with washer fixating osseous avulsion of the medial collateral ligament. Additional endobutton and screw are evidence for anterior cruciate ligament reconstruction.

    FIGURE A2-7 Cannulated cancellous screws stabilizing a femoral neck stress fracture as evidenced by sclerosis along the medial (compressive) femoral neck.

  • Screws with a hollow central shaft allowing insertion over a guidewire or pin

    Acutrak Screw

  • Most commonly used for scaphoid fractures (Fig. A2-8) and stabilization of osteochondral (Fig. A2-9) lesions of the femoral condyles

  • Cannulated, headless, fully threaded compression screw that optimizes internal holding power

    FIGURE A2-8 Acutrak screw fixation of scaphoid waist fracture. Note lucent focus within the distal radius related to bone harvest site.

    FIGURE A2-9 Acutrak screw fixation of medial femoral condylar osteochondral fragment.

    Herbert Screw

  • Previously commonly used for scaphoid fractures (Fig. A2-10); may also be used for other carpal bone fractures and small joint fusions and has been described in stabilization of odontoid process fractures

    FIGURE A2-10 Herbert screw fixation of scaphoid waist fracture with bone harvest site noted in the distal radius.

    A  B
    FIGURE A2-11 Frontal (A) and lateral (B) views of anterior cruciate ligament reconstruction utilizing bone patellar tendon bone graft with graft stabilized via interference screws.


    FIGURE A2-12 Status post anterior cruciate ligament reconstruction utilizing bioabsorbable proximal screw.

  • Headless cannulated screw with threads of differing pitch at both ends and an intervening threadless central component allowing compression of the fracture margins during insertion and fracture healing

    Interference Screws

  • Most commonly seen in the setting of anterior cruciate ligament reconstruction (Fig. A2-11)

  • Fixation devices utilized to provide immediate mechanical strength and stability of anterior cruciate ligament graft until graft incorporation; screws placed along bone blocks preventing movement

    Bioabsorbable Screws

  • Produces initial mechanical strength similar to metal but with the advantage of screw degradation of time with bone replacement

  • Postoperative imaging not limited by metallic susceptibility artifact and no need for removal in cases of revision (Figs. A2-12 and A2-13)

  • Can produce an inflammatory synovitis as seen on follow-up MRI examinations

    MBA (Maxwell-Brancheau) Screw

  • Utilized in arthroereisis, a procedure performed for correction of overpronation of the foot; a block placed in the sinus tarsi lifts up the talar head thereby correcting the pronation deformity (Fig. A2-14)

    FIGURE A2-13 MR correlate to radiograph in Figure A2-12 demonstrating the proximal screw which is radiographically occult. The bioabsorbable screw is fractured, but this is likely not clinically significant.

    FIGURE A2-14 MBA (Maxwell-Brancheau) screw in sinus tarsi status post arthroereisis with additional cannulated cancellous screw fixating calcaneal osteotomy.

  • Threaded titanium screw; other blocks may be made of bone, polyethylene disk, Silastic implant, or staple

    Dynamic Hip Screw (DHS)

  • Commonly used in the setting of intertrochanteric (Fig. A2-15), subtrochanteric, and basilar neck fractures in addition to femoral condylar fractures

  • Consists of a cancellous lag screw that moves within a metal sleeve; the sleeve is attached to a side plate that is positioned along the lateral femoral cortex and stabilized via screws

  • Extramedullary fracture fixation device with dynamic compression at fracture margins with weight bearing

    FIGURE A2-15 Dynamic hip screw stabilizing remote intertrochanteric fracture.

    INTRAMEDULLARY DEVICES

    Intramedullary Nail

  • Also known as intramedullary rod or dynamic intramedullary rod

  • Standard treatment of long-bone diaphyseal femur and tibial fractures (Fig. A2-16)

    FIGURE A2-16 Antegrade intramedullary nail fixation of distal tibial fracture with single proximal interlocking screw.

  • Share the load with bone, allowing rapid weight bearing

  • Fracture stability enhanced by the use of proximal and distal interlocking screws

    Elastic Stable Intramedullary Nail (ESIN)

  • Also known as flexible intramedullary nail (Fig. A2-17)

  • Leading indications: diaphyseal and metaphyseal long-bone fractures in pediatric (5- to 12-year-old) patients; placed in a retrograde fashion via the metaphysis, thus maintaining the integrity of the growth plate

  • Generally, two small-diameter nails inserted with opposing curves

  • Allows stable fracture fixation with early mobilization and rapid healing

    FIGURE A2-17 Flexible intramedullary nail fixation of distal femoral diaphyseal fracture in skeletally immature patient.

    Cephalomedullary Nail

  • Indications: unstable peritrochanteric, intratrochanteric, and subtrochanteric femoral fractures

  • Femoral nails with proximal blade plates or sliding screws extending into the femoral head

  • Most commonly used devices: gamma nail, proximal femoral nail (PFN), and trochanteric fixation nail (TFN) (Fig. A2-18)

    FIGURE A2-18 Trochanteric fixation nail with spiral blade plate stabilizing intertrochanteric fracture.

    Kirschner Wires

  • Also known as K-wires (Fig. A2-19)

  • Most commonly utilized for temporary fracture fixation and can also act as a guide for passage of other orthopedic instrumentation

  • Because these are generally placed percutaneously and may remain contiguous with the skin surface, infection can be seen as a complication

    ARTHOPLASTY

    Shoulder Arthroplasty

  • Indicated in the setting of degenerative and inflammatory arthropathy, fracture, and avascular necrosis

  • Most common are hemiarthroplasty and total-shoulder arthroplasty (TSA) (Fig. A2-20)

  • Hemiarthroplasty is indicated when the glenoid cartilage is relatively well preserved, when deficient glenoid bone stock prevents glenoid prosthesis, with an irreparable rotator cuff tear, in patients younger than 50 years of age, and for a proximal humeral fracture in the elderly

    FIGURE A2-19 Kirschner wire stabilization of fracture-dislocation injury of the wrist.

    FIGURE A2-20 Total-shoulder arthroplasty with radiolucent pegged polyethylene glenoid socket.

  • Complications (particularly of TSA): loosening, most commonly of the glenoid prosthetic component; glenohumeral instability; periprosthetic fracture (Fig. A2-21); rotator cuff tear; infection; neural injury; and deltoid muscle dysfunction

    FIGURE A2-21 Periprosthetic fracture associated with a shoulder hemiarthroplasty.

    FIGURE A2-22 Reverse total-shoulder arthroplasty

    FIGURE A2-23 Arthrosurface HemiCAP device utilized to treat an osteochondral lesion of the humeral head, depicted on CT arthrogram.

    Reverse Total-Shoulder Arthroplasty

  • Utilized in the setting of torn rotator cuff, rotator cuff arthropathy, or previous failed arthroplasty

  • Prosthetic socket now attached to native glenoid and metal ball now situated along the native humeral shaft; allows patients to use deltoid muscle instead of rotator cuff to lift arm (Fig. A2-22)

  • Complications: scapular notching, hematoma, prosthetic failure or loosening, glenohumeral dislocation, acromial and scapular fractures, and neural injury

    Arthrosurface HemiCAP

  • Indicated in the treatment of cartilage lesions in major joints, including at the shoulder (Fig. A2-23), knee, and first metatarsophalangeal (MTP) joint

  • Implant fitted to the native articular cartilage surface, repairing the cartilage injury and restoring the integrity of the joint surface

  • May be utilized as an interim device until more permanent total-joint arthroplasty is warranted

  • Less invasive surgical technique with preservation of bone and surrounding stabilizing soft tissue structures

    Radial Head Hemiarthroplasty

  • Indicated in the setting of a comminuted radial head fracture (Fig. A2-24) with concomitant ligamentous injury, dislocation, or radioulnar joint disruption

  • Complications: decreased range of motion, heterotopic ossification, loosening, infection, and nerve injury

    Bipolar Hip Hemiarthroplasty

  • Composed of a femoral stem and a separate acetabular cup that fit together as a functioning unit (Fig. A2-25)

  • Increased range of motion relative to conventional total-hip replacements because of motion between prosthetic head and cup and cup and native acetabulum; also reported lower incidence of dislocation

    Total-Hip Arthroplasty

  • Main indications: degenerative or inflammatory arthropathy, avascular necrosis, and trauma

  • Three main types: noncemented (Fig. A2-26), hybrid—only femoral component cemented (Fig. A2-27), and cemented (Fig. A2-28)

  • Type of arthroplasty utilized often dependent on age, lifestyle, and surgeon’s experience; older patients, those with inflammatory arthropathies, and those with compromised bone quality and density often chosen for cemented hip replacements

  • Generally faster rehabilitation for cemented arthroplasties; reported increased incidence of thigh pain in noncemented hip replacements

  • Complications: loosening (Fig. A2-29) and osteolysis (Fig. A2-30), prosthetic and periprosthetic fractures (Fig. A2-31), dislocation (Fig. A2-32), infection, and heterotopic ossification

    A B
    FIGURE A2-24 Frontal (A) and lateral (B) views of radial head replacement.

    FIGURE A2-25 Bipolar hip hemiarthroplasty with cerclage wires encircling the greater trochanter.

    FIGURE A2-26 Uncemented total-hip arthroplasty.

    FIGURE A2-27 Hybrid total-hip arthroplasty with cemented prosthetic femoral shaft and uncemented acetabular cup.

    FIGURE A2-28 Cemented total-hip arthroplasty with polyethylene acetabular socket. Note acetabular reconstruction plate and screws.

    FIGURE A2-29 Total-hip arthroplasty with mechanical loosening as evidenced by periprosthetic lucency along the metallic femoral stem-bone interface of greater than 2 mm.

    FIGURE A2-30 Osteolysis from particle disease in the setting of an uncemented total-hip arthroplasty as evidenced by well-defined periacetabular mass-like lucency.

    FIGURE A2-31 Periprosthetic fracture associated with a total-hip arthroplasty.

    FIGURE A2-32 Dislocation of total-hip arthroplasty.

    FIGURE A2-33 MDCT correlate to radiograph in Figure A2-30 shows periacetabular osteolysis. MDCT capabilities allow for prosthetic imaging with minimal image degradation by metal artifact.

    FIGURE A2-34 Hip resurfacing arthroplasty.

  • Multidetector CT (MDCT) may be helpful in assessing the total-hip arthroplasty particularly in assessing prosthetic positioning (Fig. A2-33), specifically acetabular version as well as some complications such as osteolysis

    Hip Resurfacing Arthroplasty

  • Bone conserving hip arthroplasty (Fig. A2-34) generally performed in young or physically active patients

  • Lower rates of dislocation than conventional joint replacements because of a larger prosthetic head; however, unique risk of femoral neck fracture

    Unicompartmental (Partial) Knee Arthroplasty

  • Generally indicated for arthropathy confined to a single compartment (Fig. A2-35)

  • Less invasive and shorter recovery time after procedure

    Total-Knee Arthroplasty

  • Most common indications: degenerative and inflammatory arthropathies

  • Multiple designs; generally characterized as cruciate retaining (Fig. A2-36) and cruciate substituting, constrained (Fig. A2-37) and unconstrained, and fixed bearing or mobile


    A                                                               B

    FIGURE A2-35 Frontal (A) and lateral (B) views of medial unicompartmental knee arthroplasty.


    A                                                             B

    FIGURE A2-36 Frontal (A) and lateral (B) views of cruciate-retaining total-knee arthroplasty.


    A                                                               B

    FIGURE A2-37 Frontal (A) and lateral (B) views of constrained revision-type long-stem total-knee arthroplasty.

  • Common complications: patellofemoral malalignment, instability, loosening (Fig. A2-38) and osteolysis from particle disease, infection (Fig. A2-39), periprosthetic fracture, dislocation (Fig. A2-40)

    Total-Ankle Arthroplasty

  • Most common indications: degenerative and inflammatory arthropathies

  • First-generation arthroplasties yielded poor results, thus ankle arthrodesis still remains the first-line treatment for tibiotalar disease; however, with newer arthroplasties, interest in ankle joint replacement is increasing (Fig. A2-41)

  • Reports of significant reoperation rates, most commonly for heterotopic ossification, axial malalignment, loosening, and infection (Figs. A2-42 and A2-43)

    MTP Joint Arthroplasty

  • Mainly performed in the setting of rheumatoid arthritis; degenerative arthropathy may also be an indication at the first MTP joint

  • Replacement generally consists of Silastic, metal, and polyethylene spacers (Figs. A2-44 and A2-45)

  • Complications: synovitis (Fig. A2-46) and particle disease

    FIGURE A2-38 Loose total-knee arthroplasty as evidenced by abnormal lucency along the tibial prosthetic component.

    FIGURE A2-39 Infected total-knee arthroplasty with joint effusion and periprosthetic lucency.

    FIGURE A2-40 Dislocation of revision long-stem total-knee arthroplasty.

    FIGURE A2-41 Total-ankle arthroplasty utilizing a fixed-bearing porous coated prosthesis with syndesmotic fusion.

    FIGURE A2-42 Normal total-ankle arthroplasty on initial postoperative radiograph.

    FIGURE A2-43 Infected total-ankle arthroplasty on follow-up examination demonstrating subsidence of arthroplasty.

    FIGURE A2-44 Great toe MTP arthroplasty.

    FIGURE A2-45 Lesser toe MTP arthroplasties.

    FIGURE A2-46 Silicone rubber great toe MTP prosthesis with fracture, extrusion, and resultant synovitis as evidenced by periarticular subchondral cysts.

    Antibiotic-Impregnated Cement Spacer

  • Inserted after removal of infected arthroplasty (Figs. A2-47 to A2-49) to allow partial weight bearing and range of motion

  • In addition to systemic antibiotic treatment, decreases risk of reinfection

    FIGURE A2-47 Antibiotic-impregnated cement spacer placed after removal of infected total-ankle arthroplasty.

    FIGURE A2-48 Cemented antibiotic impregnated acetabular spacer component with cemented femoral stem.


    A                                                             B

    FIGURE A2-49 Frontal (A) and lateral (B) views of antibiotic-impregnated knee cement spacer placed after the removal of an infected total-knee arthroplasty.

    SPINE

    Corpectomy and Fusion

  • Removal of vertebral body and disc spaces for decompression of the spinal canal due to stenosis, spinal deformity (kyphosis), trauma, neoplasm, and infection; cervical and lumbar spine most common

  • Instrumentation provides immediate stabilization until mature incorporation and fusion of intervertebral graft

  • Within the cervical spine, metal construct usually consists of anterior plate and intrabody screws with numerous plate designs currently on the market (Fig. A2-50)

  • In the lumbar spine, stabilization hardware generally consists of paired rods and transpedicular screws (Fig. A2-51)

  • Intervertebral graft may consist of bone or other titanium/synthetic cage devices (Fig. A2-52)

    Discectomy and Fusion

  • Removal of herniated or degenerative disc causing neurologic symptomatology

  • Intervertebral plugs utilized to maintain normal height of disc (Fig. A2-53)

  • Within the cervical spine, may or may not be additional stabilization via anterior plate and intrabody screws for single level fusion; anterior plate and screws usually utilized in the setting of multilevel cervical spine fusion (Fig. A2-54)

  • Paired rods and transpedicular screws usually complementary to anterior fusion in the lumbar spine

    Disc Replacement

  • Utilized in the setting of cervical (Fig. A2-55) and lumbar (Fig. A2-56) degenerative disc disease as an alternative to spine fusion

  • Multiple devices in use; typical design consists of metal plates apposed to the vertebral end plates with an intervening central core

  • Complications: nerve and vascular injury, back and leg pain, implant subsidence and migration, end-plate fracture, heterotopic ossification

  • Initial results show promise; longer-term outcomes are unknown

    X-Stop

  • Titanium metal spacer placed between the spinous processes (interspinous process decompression) (Fig. A2-57) to alleviate symptoms of lumbar spinal stenosis by increasing spinal canal diameter from tensioning of the ligamentum flavum

  • Advantages: minimally invasive procedure and quick recovery

  • Long-term success unknown

    FIGURE A2-50 Anterior cervical corpectomy and fusion with anterior plate, intrabody screws, and fibular strut graft.

    FIGURE A2-51 Lumbar fusion, including posterior paired rods and transpedicular screws with intervertebral bone plugs at L4-L5 and L5-S1 complicated by plug extrusion.


    A                                                                          B

    FIGURE A2-52 Frontal (A) and lateral (B) views of lumbar corpectomy with intervening titanium strut graft and paired rods with transpedicular screws.


    A                                                                 B

    FIGURE A2-53 A and B, Anterior cervical discectomy and fusion with anterior plate, intrabody screws and an intervertebral bone plug. This case was complicated by retropharyngeal hematoma demonstrated by massive prevertebral soft tissue swelling. Note surgical drain at the operative bed. There is dissection into the superior mediastinum, as evidenced by widening of the mediastinal contours.


    A                                                            B

    FIGURE A2-54 Anterior cervical discectomy and fusion with anterior plate, intrabody screws, and intervertebral femoral ring allografts (A) and intervertebral titanium cage (B).


    A                                                                          B

    FIGURE A2-55 Frontal (A) and lateral (B) views of cervical disc replacement.


    A                                                                                B

    FIGURE A2-56 Frontal (A) and lateral (B) views of lumbar disc replacement.


    A                                                                        B

    FIGURE A2-57 Frontal (A) and lateral (B) views of X-STOP device interposed between the spinous processes.

    FIGURE A2-58 Lateral mass screws and rods integrated with thoracic pedicle screws.

    Lateral Mass Plate and Screws

  • Preferred surgical technique for posterior cervical stabilization (Fig. A2-58); most commonly performed for cervical spondylosis and trauma

  • Provides greater stability than other posterior fixation techniques and can be utilized in patients who have deficient or injured posterior elements

    MISCELLANEOUS

    Cerclage Wires

  • Utilized for diaphyseal long-bone fractures (Fig. A2-59)

  • Placed around the circumference of the bone maintaining apposition of osseous structures

    Tension Band Wiring

  • Most commonly seen with patellar (Fig. A2-60) and olecranon fractures; can also be used with greater trochanter, greater tuberosity, acromial process, and tibial tuberosity fractures

  • Forces fracture fragments together in compression, counteracting pull from muscles

    Staples

  • Can be used for fracture fixation, arthrodesis, and osteotomies particularly in the hand, foot (Fig. A2-61), ankle, and knee

  • Fast and effective means of stabilization by providing compression at the site of fracture or surgery

    Endobutton

  • Seen in the setting of anterior cruciate ligament reconstruction (Fig. A2-62), generally with hamstring grafts; has also been used with distal biceps tendon repair

  • Soft tissue fixation device utilized to provide mechanical strength until repair heals

    Suture Anchors

  • Commonly used with rotator cuff (Fig. A2-63) and labral repair as well as ligamentous reconstruction, particularly at the ankle (Fig. A2-64)

  • Fixation device utilized to stabilize soft tissue to bone

    FIGURE A2-59 Cerclage wires and plate and screw fixation of periprosthetic fracture in the setting of a total-hip arthroplasty.


    A                                                       B

    FIGURE A2-60 Frontal (A) and lateral (B) views of tension band wiring and Kirschner wire stabilization of patellar fracture.

    FIGURE A2-61 Staples utilized in the setting of triple hind-foot arthrodesis. Additional cannulated cancellous screw fixates a calcaneal osteotomy.

    FIGURE A2-62 Endobutton stabilizing proximal anterior cruciate ligament reconstruction graft.

    FIGURE A2-63 Suture anchors utilized in rotator cuff repair.

    FIGURE A2-64 Suture anchors utilized in lateral ankle ligamentous reconstruction.

    External-Fixator Device

  • Most commonly utilized in fracture stabilization, osteotomies, and bone-lengthening procedures

  • Fixation achieved by passing pins proximal and distal to injured or operated bone and connecting these pins to external fixation device (Fig. A2-65)

    FIGURE A2-65 Ex-fixator device stabilizing a midshaft femoral osteotomy.