Graham S. Devereux

• Professor of Respiratory Medicine
• Division of Applied Health Sciences
• University of Aberdeen
• Consultant in Respiratory Medicine
• Aberdeen Royal Infirmary
• Aberdeen, UK

The cavitary defect in the femur is filled with a bisected femoral head allograft liquid oral antibiotics for acne zithromax 250 mg buy with mastercard, which is flush against host bone and stabilized with two compression screws bacteria kingdom order line zithromax. The proximal end of the graft should rest against viable host bone antimicrobial jobs 250 mg zithromax purchase with mastercard, with mechanical stability and maximum host bone­allograft contact to promote healing antibiotic resistance quiz zithromax 100 mg purchase mastercard. Conservative resection of the distal femur to match the end of the allograft will accomplish contact between host bone and allograft infection videos best zithromax 500 mg. Once stabilized, the allograft distal femur within the host cortex is sized and cut to match the revision femoral compoment. Collateral ligaments, if present, are preserved on the outer shell of host cortical bone. The graft­host bone junction can be cut in a step-cut configuration to ensure rotational stability. In all cases of allograft reconstruction of the distal femur, offloading of the graft and rotational stability should be ensured by using an intramedullary rod attached to the revision femoral component. If necessary, the rod can be cemented into the allograft and host bone for stability, although extrusion of cement at the host bone­allograft junction must be avoided to allow healing at this junction. Severe deficiency of both femoral condyles can be addressed by pressing an undersized distal femoral allograft into this void, while retaining the host cortical bone around it. After stabilization to surrounding host bone with screws, the allograft­host composite is shaped to receive the revision femoral component. To replace the distal femur, existing epicondyles are osteotomized, and the deficient distal femur is cut to expose viable, stable host bone. To accomplish this step, the epicondyles on the bulk allograft must be cut off and removed. Before final implantation, check the soft tissue envelope to make sure inadvertent over-sizing has not occurred. The revision implant is positioned in the bulk allograft that was cut to accept the implant. The medial and lateral epicondyles have been screwed into their corresponding anatomic locations on the bulk allograft. Template radiographs and have appropriate reconstruction systems available, with varying modular lengths to rebuild the deficient femur. Perform an osteotomy of the femur to expose viable bone that is suitable for weight bearing. Prepare the femur retrograde for cementing, using techniques similar to those for cementing a femoral implant in total hip replacement surgery. Use trial and error to reproduce the appropriate limb length, soft tissue tension, and implant rotation. This is most easily accomplished by reconstructing the tibial side first, so that all trial reductions can be assessed by changing the femoral side only, thereby simplifying the procedure. When correct rotation and length are determined, mark the host bone and implant to reproduce this rotation, and cement the implant into the distal femur to the appropriate depth, and in the desired rotation. Uncemented fixation into the distal femur may be an option with some reconstruction systems. Assemble the knee articulation (these designs usually rely on a rotating hinge articulation with multidirectional constraint built into the articulation). In severe cases, or if the proximal femur is unsuitable for mechanical fixation with an intramedullary rod, the entire femur can be bypassed with metal. In such cases of complete femoral replacement, a rotating hinge knee reconstruction is done at the distal end, and a constrained hip replacement at the proximal end. Anticipate more bone loss than that seen on radiographs and prepare for the worst-case scenario. Have a wide selection of implants available, with metal augments, intramedullary rod extensions, offsets, and implants with increasing amounts of constraint. Several allograft femoral heads and equipment for milling, grinding, and shaping these heads should be available. Fixation of grafts to host bone requires interfragmentary screws and small plates, which should be readily available. Two or more graft specimens must be available for distal femoral allograft replacement so that the closest size can be chosen. Oversized grafts will present problems with wound closure; check soft tissue tension before final fixation of the graft to host bone. Be realistic about surgeon experience, support, equipment, and resources available to perform complex distal femoral reconstruction. Specialized training and intense equipment and personnel demands effectively preclude smaller community institutions from doing such surgery. Either avoid using a tourniquet, or be wary of the tourniquet time in lengthy total knee reconstructions. If necessary, the tourniquet can be let down for selected parts of the procedure to minimize limb ischemia time. Accordingly, the surgeon should aim for weight bearing as soon as possible after surgery. If allograft reconstruction of the femur is necessary, healing to host bone occurs over a prolonged time. Therefore, protected weight bearing will be required for an extended period of time in such cases. Range of motion should be assessed intraoperatively following distal femur reconstruction. Usually, the range of motion will depend on the quality of the soft tissues and integrity of the extensor mechanism, assuming mechnical stability of the reconstruction has been achieved. If knee range of movement must be limited for a period of time, a knee brace that allows movement only through a prescribed arc of motion may be necessary. Straight leg raises, isometric exercises, and ankle and calf rehabilitation should be possible soon after all distal femoral reconstructions. A multimodal deep venous thrombosis prevention regimen should be instituted after surgery, and the patient monitored as appropriate. Early diagnosis and aggressive wound débridement may salvage the situation in some instances, but removal of all allograft, cement, and implants in preparation for a staged reconstruction usually is necessary. Late deep infections with a virulent organism in a knee with massive bone loss and allograft reconstruction of deficient host bone may necessitate a limb amputation. Mechanical failure of distal femoral reconstructions usually occurs if the surgeon fails to achieve initial mechanical stability. Repeat surgery is necessary to rebuild the femur and achieve rotational and axial stability to permit protected weight bearing after the procedure. If a tense hematoma develops, or new wound drainage is encountered, aggressive surgical decompression should be considered early, to avoid the risk of infection. Distal femoral allograft reconstruction for massive osteolytic bone loss in revision total knee arthroplasty. Treatment of major defects of bone with bulk allografts and stemmed components during total knee arthroplasty. Morsellized bone grafting compensates for femoral bone loss in revision total knee arthroplasty. Radiographs should be assessed for stability of the reconstruction, and for healing of bone at the allograft­host bone junction. Bulk allografts heal to living host bone, and allograft bone away from this healed junction remains non-viable over the long term. In load-sharing configurations, where the allograft is supported by host bone or by metal implants, the long-term outcomes are excellent. If allograft bone is used in load-bearing configurations, late failure of the non-viable bone from repetitive loading is predictable. Allograft bone cannot remodel in response to stress; therefore, intramedullary stems that bypass the graft completely and transfer loads to living host bone are essential during the reconstruction. In some complex reconstructions involving distal femur replacements with bulk allograft or limb salvage implants, the patient should be counseled to use protected weight bearing for a prolonged time, such as 6 months or longer. Awareness and proper management of bone loss, through cement fill, metal augments, or bone grafting, are crucial for achieving stability and longevity of the newly implanted revision components. The most common areas of deficiency involve the posterolateral and medial tibial plateau. Smaller contained defects can often be addressed with morselized bone graft or cement alone. Larger, uncontained defects may require the use of metallic wedges or structural allografts. A full history and physical examination are essential, and should include an assessment of type, quality, location, and duration of pain. Any new, severe pain or progressive pain in a previously well-functioning implant, particularly during weight bearing, is of particular concern. A new onset of slowly progressive symptoms "giving out" or weakness of the knee can be an indication of problems. Local tenderness along the interface between the tibial implant and the tibia can be seen in tibial component loosening. The extent and location of bone loss, the quality of the remaining bone, the degree of cortical continuity, and the absence of infection must be determined. All patients should have the appropriate infection laboratory studies (ie, complete blood count, C-reactive protein, erythrocyte sedimentation rate) as well as an attempt at knee aspiration and synovial fluid sent for Gram stain, cell count, and culture. Serial knee aspirations with repeat laboratory studies often are performed on patients with a high index of suspicion for infection. Aseptic implant loosening can result in pathologic micromotion at the implant­bone interface, resulting in increased wear debris and formation of a biologically active membrane. Removal of well-fixed implants, even using proper technique, can result in some degree of bone loss, particularly from the subchondral region. However, if revision is not deemed a safe option for medical, psychosocial, or other reasons, management is similar to that for a patient with endstage knee arthritis. Treatment options are symptom based and can include activity modification, walking aids, nonsteroidal pain medications, and bracing. Cement filling Morselized particulate bone grafting Modular metal augments Modular endoprostheses Structural allograft Impaction bone grafting12 Preoperative Planning Bone loss around a knee implant should be assessed systematically, including both femoral condyles, both tibial plateaus, and the patellofemoral joint. The choice of reconstruction depends largely on the type of bone loss (ie, contained or uncontained) and the location and size of the defect (Table 1). The medial collateral ligament is circumferentially released from the proximal tibial metaphysis as a single sleeve. Additional exposure often is required if metal wire mesh is need for unconstrained defects. The proximal portion of the tibia must be well exposed to ensure fixation of the wire mesh onto the bone. External rotation of the tibia and elevation of the medial sleeve often help with exposure of the cortical margins. The patellar tendon should be protected throughout the entire procedure, and the patella should not be everted, to minimize the risk of avulsion. In cases with severe joint ankylosis, the surgeon should be prepared to convert to more extensive revision approaches if necessary to obtain visualization (eg, quadriceps snip, tibial tubercle osteotomy, or V-Y quadricepsplasty). A formal synovectomy with sharp dissection is performed for removal of polyethylene wear particles and improved exposure. Following removal of the components, a high-speed burr is used to define bony lesions, clean multiloculated defects from cavitary defects, and decorticate sclerotic areas. A trial stem is inserted into the tibial canal in proper alignment, bone graft is impacted around the stem, and the stem is removed when the bone graft has filled the defect. Wire mesh is molded to estimate normal contours of the proximal tibia and is held in place with small cortical screws. A central intramedullary guide rod with cement restrictor is inserted to allow a gap of 2 cm from the anticipated end of the final tibial stem component. The final chosen stem should be smaller to allow for a 2-mm circumferential cement mantle. Thawed fresh-frozen morselized cancellous allograft is introduced into the tibial canal and impacted tightly around the stem using either cannulated or standard tamps and a mallet. Primary components have been removed, and the lesion has been found to have intact cortices. A trial stem is inserted into the tibial canal in proper alignment, bone graft is impacted around the stem, and when the bone graft has filled the defect, the stem is removed. Intraoperative photograph showing a wire mesh cage contoured to reestablish approximate proximal tibial anatomy and held in place with small cortical screws. The trial tibial stem is inserted in proper alignment, and bone graft is impacted surrounding the stem. Cement is introduced in the impaction grafting site, the real component is inserted, and excess cement is removed. Thaw the allograft material in warm saline for 15 to 20 minutes and mount in a grip device. The host bone is reamed to expose healthy, bleeding cancellous bone, including removal of all fibrous tissue and cement. The allograft is placed into the defect and provisionally secured with K-wires or Steinmann pins. The femoral head allograft is secured into a grip device and a female-type cheese grate reamer is used to denude the allograft of cartilage and subchondral bone. A male-type reamer of appropriate size is used to create a socket for the allograft. The allograft is cut to the appropriate height and fixed with cancellous bone screws.

The number of points to be acquired is shown in the center of an acquisition clock infection ios order 500 mg zithromax free shipping. To begin multiple landmark acquisition treatment for sinus infection and bronchitis 500 mg zithromax order visa, the tip of the pointer is touched to the required structure and pivoted slightly antibiotics kidney disease purchase zithromax master card. During acetabular reaming bacteria 1000x zithromax 100 mg fast delivery, these angles are updated dynamically antibiotics for klebsiella uti discount 500 mg zithromax free shipping, indicating how far they are inclined, anteverted, or retroverted. Subsequent reaming can then continue in increments of 2 mm, with under-reaming by 2 mm less than the acetabular component to be inserted. Before the actual acetabular cup is inserted, a trial cup generally is used to verify that the selected cup size and angle are correct. The angle of the acetabular cup is shown dynamically during insertion of the component. Cup placement is verified by acquiring five points along the peripheral margin of the acetabular cup. The tab page shows both inclination and version of the acetabular cup and compares the difference between real and planned angles. The cup should be positioned using the anatomy as a reference and aligned with the bone. Once cup verification has been finished, the pelvic reference array, bone fixator, and two pins are removed, and femoral preparation proceeds. They can be inserted into the proximal diaphyseal area, but the lesser trochanteric area is more comfortable and requires a smaller incision. Before starting registration, as many osteophytes are removed as possible, because the presence of osteophytes will affect the femoral notching calculation. The fixation pin is inserted to the lesser trochanter using an automated drill at low speed. Once the second fixation pin has been inserted correctly, the bone fixator is attached and the femoral reference array connected to it. Sufficient space should be available to facilitate drilling, reaming, and implant positioning without moving the reference array. Each point is acquired by holding the tip of the pointer to the surface of the skin at the required location. This point is essential for navigation to define the proximal endpoint of the shaft axis. If this point is not defined correctly, the calculated neck axis and implant position may not be accurate. This step is important for precise morphologic estimation and for determining the center of rotation and the required implant size. These points are used for estimating the neck axis and required implant size and for generating the femoral bony model. This step is used to ensure that sufficient points have been acquired in the most critical area of the femur, where notching is most likely to occur. After verification of the femoral model, the current neck­shaft angle is shown automatically, and the surgeon can adjust the angle if necessary. As the drill guide is moved, the angle values are updated dynamically, indicating how far varus or valgus, anteverted or retroverted the implant is compared to the planned values. A stylus is used through the guide pin to estimate anterior, posterior, superior, and inferior femoral cutting lines and the possibility of femoral notching. The drill guide is placed over the pin and slid onto the surface of the femoral head to verify the position of the guide pin. The navigation system calculates the position of the implant according to the position of the drill guide. Once the verification process has been finished, the surgeon proceeds to the next step without navigation. If necessary, the surgeon adjusts the implant size manually according to the preoperative planning and matches the size with the acetabular component. Femoral Preparation Using Navigation Once navigation planning for head implantation has been finished, the drill guide pin is inserted into the femoral head using navigation. The guide pin is moved along the varus­valgus axis and along the antegrade­retrograde axis. The remaining procedures for femoral component are done in the same manner as those for conventional resurfacing procedures described earlier. Because the acetabular component has no screw holes, and the inner surface consists entirely of polished area, the surgeon cannot see the inner acetabular surface during insertion of the acetabular component. Furthermore, when acetabular osteoporosis is present, the surgeon should be careful to obtain a secure fit of the acetabular component, because additional screw fixation is impossible. To prevent under-seating of the acetabular cup, put the trial cup into the fully reamed acetabulum first and check the relation between the peripheral rim of the trial and the acetabulum. Then, when the cup is fully seated in the acetabulum, insert a real cup seated at the same depth as the trial. I prefer to use a 1-mm under-reamer rather than the 2-mm under-reamer to easily achieve a fully seated acetabular cup. Prevent femoral notching Thorough preoperative templating to determine the ideal inlet point for the femoral guide pin is mandatory. Do not ream the entire femoral head all the way to the distal rim of the femoral head. Use a rongeur to carefully remove any remaining distal rim of the femoral head to prevent further damage to the cervical blood supply and possible notching by a motorized reamer. Check notching with the stylus several times during femoral preparation, especially in the anterior and superior portion of the femoral head, which is the most vulnerable for notching. The patient must use crutches and then a cane to support weight bearing for 2 months to resist mechanical stress and permit femoral neck remodeling. Femoral component seating Use a custom-made femoral trial before insertion of the real component and check the relation (gap) between the lower peripheral margin of the trial and the distal rim of the femoral head when the trial is fully seated. Insert the femoral component before the "dough" stage of cement is finished; cement that is too hard may prevent the femoral component from being seated. Pros: Retracting the femoral head for acetabular preparation is relatively easy, because the femoral head is smaller after femoral preparation. Cons: A mismatch between the acetabular and femoral components can develop after femoral preparation. An already prepared, mainly cancellous, femoral head may be damaged during retraction. Cons: It is not easy to obtain sufficient anterior retraction of the whole femoral head during acetabular preparation. An antithromboembolic stocking is applied immediately after the operation to prevent deep vein thrombosis and permit mobilization on the first day after the operation. Coumadin can be administered for several weeks for medical prevention of deep vein thrombosis. We continue partial weight bearing with crutches for 4 to 6 weeks to allow initial bony ingrowth on the acetabular side and to allow the patient to regain normal gait and balance. To allow femoral remodeling around the neck area, we usually recommend that the patient use a cane until the end of the second month after the operation, after which full weight bearing is permitted. Light sports activity may begin no sooner than 3 months after the operation, after which the patient may even squat on the floor. Patients are allowed to ride in a car as a passenger, drive a car, sleep on their side, or engage in any activities if able and so desired. Three failures required revision or reoperation: one femoral neck fracture (at 3 weeks); one progressive avascular necrosis of the femoral head that failed at 2 years; and one low-grade infection leading to failure at 2 years. Two traumatic dislocations were incurred by an inebriated patient; these were reduced without anesthesia. Nineteen percent of the patients experienced a clicking, locking, or clunking noise or feeling in the first 6 months after surgery, but it was painless and disappeared gradually. Lilikakis and Villar11 reported the results of uncemented resurfacings with a hydroxyapatite-coated femoral implant with a minimum of 2 years of follow-up. Itayem et al9 used radiostereophotogrammetric analysis to study the stability of 20 resurfacing arthroplasties over a follow-up period of 20 months. This analysis found no evidence of excessive early migration or loosening of the components. These results suggest that the hip resurfacing system transfers load to the proximal femur in a more physiologic manner than conventional long-stem devices, that it may prevent stress shielding, and that it preserves the bone stock of the proximal femur. Shimmin and Back14 carried out a national review of fractures associated with Birmingham Hip Resurfacing systems implanted between 1999 and 2003 in Australia. Significant varus placement of the femoral component, intraoperative notching of the femoral component, and technical problems were the common factors in 85% of cases. Amstutz et al1 presented their experience with femoral neck fractures that occurred after metal-on-metal hybrid surface arthroplasty. In a series of 600 resurfacings, five femoral neck fractures occurred (incidence 0. All five fractures were associated with structural or technical risk factors, which may have weakened the femoral neck. We suggest avoiding or minimizing notching of the femoral neck by performing the cylindrical reaming at the recommended angle of 140 degrees and by stopping reaming before the reamer touches the lateral cortex. Precision fit surface hemiarthroplasty for femoral head osteonecrosis: long term results. Comparison of results of resurfacing arthroplasty performed using a navigation system and conventional technique. Hydroxyapatite-coated femoral implant on metal-on-metal resurfacing hip arthroplasty: minimum of two years follow-up. Metal on metal surface replacement of the hip: Experience of the McMinn prosthesis. Further simplification of this classification divides these fractures into displaced versus nondisplaced fractures. Guidelines for treatment of nondisplaced femoral neck fractures are beyond the scope of this chapter. The indications for a hemiarthroplasty of the hip include displaced femoral neck fractures and salvage for massive acetabular osteolytic defects in revision hip replacement. Published reports suggest that bipolar hemiarthroplasty has poor outcomes when used as a primary prosthesis for failures with degenerative joint disease, and this technique currently is not recommended. The bipolar prosthesis has been favored because of its theoretical reduction of wear on the acetabular side, because motion between the inner and outer heads of the prosthesis leads to less motion at the acetabulum­implant interface. Several mechanisms have been proposed: A direct blow to the lateral aspect of the greater trochanter from a fall A sudden increase in load with the head fixed in the acetabulum along with a lateral, rotatory force. Completion of a fatigue fracture that precedes and causes a fall the incidence of femoral neck fractures increases as bone density falls to osteoporotic levels. Femoral neck fractures in young patients typically are the result of high-energy mechanisms. The mechanical explanation is axial loading of the distal femur or the foot if the knee is extended. The amount of bony displacement and associated soft tissue injury can be much higher. Displacement of a femoral neck fracture can lead to disruption of the vascular supply of the femoral neck. Some ethnic groups (eg, Asians) have a propensity for higher degrees of anteversion, up to 30%. In cross section, the femoral neck is cam-shaped, with a shorter anteroposterior than mediolateral diameter. The calcar femorale is a condensed, vertically oriented area of bone that originates superiorly toward the greater trochanter and fuses with the cortex at the posterior aspect of the femoral neck. The major vascular supply of the femoral head comes from the lateral epiphyseal branch of the medial femoral circumflex artery. Finding a demented patient down on the floor and unable to ambulate also should raise suspicion for a femoral neck fracture. His or her preoperative activity level can help determine the most appropriate type of surgical management. Care must be taken to evaluate other possible sources of injury about the hip as well as associated ipsilateral injury. Acetabular fracture: In a low-energy injury, acetabular fracture is an uncommon association with a femoral neck fracture. Inter- and subtrochanteric fracture: Injury to the intertrochanteric area is commonly seen about the hip in elderly patients. Usually, the limb is held in extension, not in a flexed, externally rotated position. A thorough physical examination should include: Observation of the lower extremity. If it is shortened, externally rotated, and painful to move, a joint effusion secondary to fracture hematoma is most likely responsible, which increases the available space in the joint capsule. A positive result elicits pain at the groin due to the side-to-side movement of the lower extremity, which creates shear forces across a femoral neck fracture, leading to exquisite pain. Pain at endpoints of the range of motion may be the only clue to a nondisplaced occult fracture. Femoral head blood supply is then dependent on remaining retinacular vessels and those functioning vessels in the ligamentum teres. The incidence of nonunion following a displaced fracture is as high as 60% with nonoperative treatment in some reports. Femoral neck fractures can be divided into subcapital, transcervical, and basicervical types, based on the location of the injury.

The pelvic landmarks that assist in component removal and positioning include the ischium treatment for dogs back legs generic zithromax 250 mg online, pubis bacteria in bloodstream order zithromax 250 mg free shipping, anterior and posterior acetabular columns bacteria resistant to antibiotics order zithromax 500 mg with visa, anterior inferior iliac spines virus yardville nj 500 mg zithromax overnight delivery, transverse acetabular ligament antimicrobial wound cream zithromax 100 mg discount, sciatic notch, and acetabular walls. Neurologic structures at risk include the sciatic nerve, which can be identified in three distinct anatomic locations: As it exits the sciatic notch Lying over the ischium posterior and inferior to the posterior acetabular column Beneath the femoral insertion of the gluteus maximus tendon insertion into the posterior femur. The superior gluteal nerve is at risk during component removal as it travels anteriorly along the ilium, approximately 4 to 5 cm superior to the tip of the greater trochanter, to innervate the gluteus medius muscle. The femoral nerve is well anterior to the hip for most approaches but may be at risk with further anterior dissection and retraction and with anterior supine approaches to the hip. The femoral artery and vein are well anterior to the dissection and usually are protected by the iliopsoas tendon and muscle belly. The proximal femoral anatomy includes the greater and lesser trochanter and the vastus ridge, which is a point of relatively weak bone in most revisions due to osteolysis, previous trochanteric osteotomies, or previous surgery in this area. The femoral diaphyseal anatomy includes the attachments of the vastus musculature at the vastus ridge and posteriorly at the linea aspera. Both are indications for trochanteric osteotomy to facilitate exposure of the acetabulum and possible stem removal. The sepsis usually progresses rather quickly to the implant interfaces despite well-fixed implants and usually cannot be treated effectively with irrigation and joint débridement alone. Component removal with attention to bone preservation for subsequent reconstruction is crucial. Judet oblique radiographs demonstrating anterior column deficiency and acetabular loosening with a well-fixed stem. Biplanar radiographs of the entire implant and the joint above and below the prosthesis are essential. These findings are helpful in guiding plans for bone grafting of lytic lesions and identifying remaining bone stock. Plain radiographs usually greatly underestimate the extent of osteolysis involvement in the pelvis from polyethylene debris. Bone scan examination may demonstrate subtle implant loosening that may not be appreciated on plain radiographs or at the time of surgery and may help the surgeon decide whether to retain or remove implants that appear well fixed. Care should be taken to preserve as much bone stock as possible during the removal for subsequent reconstruction. These osteotomes are designed so that the rotation point is in the center of the acetabular component. Positioning In general, patients can be positioned supine or in the lateral decubitus position. In the anterior supine approach, the patient is positioned in the supine position and an anterior approach to the hip is performed in the interval between the tensor fascia lata and the sartorius muscles. An anterior or anterolateral approach to the hip can be performed in the supine or lateral position and is extensile in both the proximal and distal directions should additional exposure be required. An axillary roll is used to provide protection for the brachial plexus during surgery. This approach retains much of the posterior capsule and structures, which likely reduces the incidence of dislocation after revision. Lateral A direct lateral approach to the hip involves a split in the anterior third of the gluteus medius and minimus musculature. Acetabular exposure with retractors in place before femoral head dislocation in this hip, which shows severe polyethylene wear and osteolysis. New polyethylene liner is inserted with the femoral head in view and retracted posteriorly. The vastus lateralis remains attached to the lateral portion of the osteotomy but is reflected anteriorly to allow visualization of the lateral and posterior femoral cortex. An oscillating saw is used to perform the posterior portion of the osteotomy just superior to the linea aspera. The distal extent of the osteotomy is beveled in the distal and anteroposterior direction. The anterior portion of the osteotomy is made with a small (1/4-inch) osteotome perforated through the vastus musculature. The capsule surrounding the prosthesis below the greater trochanter is released or excised and the "shoulder" of the prosthesis exposed. About one third of the lateral portion of the femoral circumference is part of the osteotomy. The vastus lateralis that remains attached to the lateral portion of the osteotomy is reflected anteriorly to allow visualization of the lateral and posterior femoral cortex. The anterior portion of the osteotomy is made with a 1/4-inch osteotome perforated through the vastus musculature. The entire extended trochanteric fragment is reflected anteriorly, with care not to fracture the tip of the trochanteric fragment, which is the weakest point in the osteotomized fragment. Bennett and Charnley retractors retract soft tissue and the trochanteric fragment to visualize the femoral prosthesis. The cement­implant and cement­bone interfaces or the ingrowth interface is now accessible. The trial implants are inserted and a trial reduction performed before the trochanteric fragment is reattached. Anterior and medial capsular attachments are taken down to the level of the psoas tendon. All tissue lateral to the psoas tendon can be removed at this point if needed to allow visualization of the stem. Osteotomes, ultrasonic devices, or high-speed burrs now have access to the cement­implant and cement­bone interfaces or the ingrowth interface, as needed for removal. The femoral preparation for long-stem implant insertion is completed with flexible reamers and proximal femoral tapered reamers. The trial implants are inserted and a trial reduction performed with the trochanteric fragment not attached. It is important not to gouge the acetabulum or to break off large pieces by aggressively twisting or pulling a well-secured cup. Acetabular osteotome systems facilitate cup removal by using the center of the acetabular polyethylene as a reference for osteotome insertion. The osteotome blade is inserted and turned in a firm, controlled manner, maintaining its orientation to the rim of the cup. First, a small osteotome is inserted that matches the radius of the acetabular component. The acetabular osteotome used to remove cups allows thin osteotome insertion precisely in the bone implant interface. A small osteotome is first used to enter the bone­implant interface around the rim of the acetabular component. Using the acetabular explant chisel on a handle, the implant is removed with minimal bone loss. Extended trochanteric osteotomy Bevel the distal transverse arm of the osteotomy to prevent distal fracture propagation. Pass a cerclage wire distal to the osteotomy before femoral preparation and trial and final implant insertion. Pay careful attention to trochanteric osteolysis and fracture risk at the vastus ridge at the junction of the vastus lateralis and the abductor attachment into the trochanter. Have adequate bone graft available, including morselized cancellous graft and cortical struts for contained and uncontained defects. Leave vastus muscle attached to the trochanteric fragment to provide adequate blood supply for osseous healing and implant stability. The polyethylene should be removed from the acetabular component to allow screw removal, then replaced for a guide or reference for removal instruments. Cementing an acetabular polyethylene shell is an option if the locking mechanism is not functional after polyethylene component removal. With polyethylene exchanges and component retention of osseointegrated implants, weight bearing as tolerated is recommended. When an implant is removed and an antibiotic-impregnated static spacer is inserted, foot-flat (essentially non­weight bearing) weight bearing is recommended. The fate of stable cemented acetabular components retained during revision of a femoral component of a total hip arthroplasty. The fate of stable femoral components retained during isolated acetabular revision: a six-to-twelveyear follow-up study. Acetabular deficiencies may be extensive in the face of polyethylene wear and osteolysis. The proximal aspect of the femur is composed of the head, the neck, and the greater and lesser trochanters. Vascular and neurologic structures include the femoral artery and vein and the sciatic nerve. The presence of this debris increases over time, leading to a macrophage response that results in periprosthetic bone loss. Aseptic loosening may occur secondary to this particle-induced periprosthetic osteolysis. Other systemic medical conditions and recent surgical or medical treatments should also be documented to ensure that the patient can tolerate and will benefit from hip revision. A Trendelenburg gait or abductor lurch may raise concern regarding hip abductor function that can limit success of revision. Trendelenburg test is considered positive if pelvis on the nonstance side moves into a position of relative adduction; this may indicate abductor weakness or trochanteric nonunion. A palpable or audible click or clunk may indicate head subluxation or a loose component. Hip abductor strength may indicate abductor weakness, trochanteric bursitis, abductor avulsion, trochanter fracture, or a loose femoral component. A slight difference of less than 1 cm in true leg length is considered normal, though it may cause symptoms in some patients. Apparent leg length may be affected by atrophy, obesity, or asymmetric positioning of the legs. Values may indicate abductor or adductor contractures, or pelvic obliquity due to scoliosis. Evaluate the skin around the hip to gauge the risk for infection and to assess its ability to heal postoperatively. A careful neurologic and vascular evaluation should be performed to rule out extrinsic etiology for hip or thigh discomfort. Bone Careful evaluation of the preoperative radiogaphs is imperative to identify bony deficiencies. Proximal bone deficiencies around the lesser trochanter can be so profound that a fluted stem is not suitable for femoral revision and a fully porous coated stem for diaphyseal fixation is preferable. Diaphyseal defects in the femur are important to identify since it is critical for the stem to bypass cortical deficiencies by at least two cortical diameters. A complete medical and surgical history is necessary to document all information pertaining to the index procedure, including the initial diagnosis, date of surgery, complete operative notes with detailed descriptions of the components used, and the dates of any postoperative complication. Soft Tissue the hip abductors require careful preoperative evaluation and intraoperative inspection since they are critical to postoperative hip stability and gait. The 5-cm insertion frequently needs to be partially or completely released to gain exposure or correct leg length. The vastus lateralis may be elevated from its posterior border to give the surgeon access to the femoral shaft for correction of bony deformity, fracture repair, and cable placement. Neurovascular Structures the sciatic nerve is frequently encased in scar during revision hip surgery. Table 2 Patient Description of Pain and Potential Diagnoses Potential Diagnosis Implant failure or indolent infection Sepsis Deep pyogenic infection Aseptic loosening Loose femoral component, tendinitis, or heterotropic ossification Periprosthetic femur fracture, acetabular cup disassociation, or hip dislocation Extrinsic source unrelated to the hip Description of Pain the posterior hip joint capsule and the short external rotators are often scarred together. They need to be tagged and preserved for later repair if a posterior approach to the hip has been used. Many times, the anterior joint capsule is scarred and must be completely resected to correct offset and leglength abnormalities. Polyethylene debris may be located in the iliopsoas sheath and should be eliminated during the hip revision. The iliopsoas may require anterior release to correct leg length and preoperative flexion contractures. If the surgeon needs to expose the nerve, it is best identified posterior to the gluteal sling and followed proximally toward the hip joint. Comparison of the most recent radiograph with the oldest postoperative one is the most reliable way to document implant migration. The aspirate should be assessed for cell count with a differential as well as culture and sensitivity. Also, pain relief with lidocaine injection indicates an intra-articular etiology, further supporting need for revision arthroplasty. Serial radiographs can be used to follow a loose femoral stem if infection has been ruled out and no significant bone loss is occurring. Bisphosphonates may improve bone stock, although this has not been proved in humans. Suppressive antibiotics for septic loosening may help control pain or progressive infection in a nonoperative patient. Hip pain due to bursitis may be improved with nonoperative treatments, including physical therapy, nonsteroidal antiinflammatory drugs, or injections. Table 3 Step 1 2 3 Step-by-Step Procedure for Templating Prior to Revision Hip Arthroplasty With a Modular, Fluted Stem Instructions Compare location of the lesser trochanter of the operative and nonoperative leg in relation to either the transischial or transobturator lines. Draw straight line up the endosteum of lateral femoral cortex, which represents the final lateral position of the implant. Failing to respect or address this line can lead to lateral perforation or varus implantation. Review the entire femoral length, and attempt to bypass the lowest femoral defect by 2. Judge center of rotation for stem/neck/head combination to obtain appropriate length. Position the sleeve on the anteroposterior view, and choose position and size of triangle.

Care must be taken with draping to ensure access to the anterior pelvis up to the groin crease to allow adequate surgical exposure xylitol antibiotics zithromax 250 mg buy free shipping. My preferred incision is a 3- to 4-cm oblique incision along the inguinal ligament that starts at the anterior superior iliac spine and is directed inferomedially antibiotics for kitten uti generic zithromax 250 mg buy on-line. The psoas tendon is approached at the same level (the pelvic brim) and therefore the exposure of the tendon is more difficult from this more proximal incision virus spreading in us 250 mg zithromax buy overnight delivery. The proximity of the femoral neurovascular structures has been well documented and is a cause for caution virus 46 states purchase zithromax 250 mg on line. Common findings of coxa valga (although femoral anteversion cannot be eliminated as a possibility): break in the Shenton line indicating subluxation antibiotics for bronchitis purchase cheapest zithromax, incomplete femoral head coverage, pelvic obliquity (right side elevated), mild windswept hips (right adducted), and mild acetabular dysplasia (right greater than left). The lateral femoral cutaneous nerve typically crosses the surgical wound and is identified and protected, but sometimes it is medial and not encountered. By isolating it from the surrounding muscle, the structure is confirmed to be the psoas tendon. Many patients have a psoas minor tendon, which must also be identified and divided. Right hip (patient supine, feet to the left); ilium, and inguinal ligament are marked. Skin incision along inguinal ligament starting just distal to anterior superior iliac spine and extending distally 3 to 4 cm. Adson forceps identify the inguinal ligament with the external oblique fascia proximal and medial. External oblique fascia is divided along the inguinal ligament and retracted by Army-Navy retractors to visualize the internal oblique. A hemostat bluntly pierces the internal oblique and transversus abdominis just medial to the anterior superior iliac spine and is passed along the inner table of the ilium extraperiosteally (in this case, the lateral femoral cutaneous nerve was not encountered). With the hip flexed, the interval between the superior pubic ramus and the iliacus is developed with blunt finger dissection to palpate the psoas tendon. The psoas tendon is visualized by retracting the iliacus medially with an Army-Navy retractor. For ambulatory patients, this is typically the only tissue that should be lengthened. If necessary, for nonambulatory patients and for more severe neuromuscular hip dysplasia, a partial or complete division of the adductor brevis and other contracted tissues can be performed. A short transverse incision (pubis left, knee right) exposes the tendinous origin of the adductor longus (pectineus laterally, gracilis medially). On the other hand, identification of pathology and indications for psoas lengthening in the ambulatory cerebral palsy patient are less well agreed upon. As a result, I believe that psoas lengthening is too often not included in the surgical plan. In the 1970s, Bleck recognized that release of the iliopsoas tendon at the lesser trochanter in the ambulatory patient resulted in excessive weakness. In nonambulators, the iliopsoas combined tendon can be released from the lesser trochanter, but care must be taken not to violate the apophysis of the lesser trochanter in order to avoid heterotopic bone formation along the iliopsoas tendon sheath postoperatively. If significant spasticity is present, pain and spasm may lead to difficulty in maintaining postoperative positioning in extension and abduction, leading to recurrence of hip flexion or adduction contractures. Botulinum toxin injected into the hip flexors and adductors at the time of surgery, effective pain management, and meticulous care to avoid postoperative positioning in flexion and adduction are essential. Because of this iatrogenic risk with limited corrective options, this procedure should be abandoned. The femoral nerve, artery, and vein are very close to the psoas tendon but are anterior to the iliacus muscle. The iliacus muscle belly can provide protection for these structures if the surgical approach is deep to it. Other protection is afforded by performing the lengthening of the tendon with the hip in the flexed position to relax the neurovascular structures, directly visualizing the tendon within the muscle belly, and stimulating the tissue with electrocautery first before cutting (if the nerve is nearby, the knee will extend). The combination of femoral anteversion with hip and knee flexion deformity results in the visual appearance of a scissoring gait in ambulatory cerebral palsy patients and is more commonly the cause of scissoring. In ambulators, only adductor longus tenotomy should be performed, and it should be performed rarely. The adductors are more commonly spastic and contracted in more severe hemiplegic cerebral palsy. Adductor lengthening An abductor pillow is used full time for 3 weeks and part time for the next 3 weeks, and early range of motion is instituted. These procedures are commonly performed in conjunction with osteotomy surgery, in which case weight bearing is typically begun 3 to 4 weeks postoperatively. When psoas lengthening is performed in conjunction with femoral derotation osteotomy, excessive anterior pelvic tilt may also improve. Postural and gait abnormalities caused by hip-flexion deformity in spastic cerebral palsy: treatment by iliopsoas recession. Intramuscular psoas lengthening improves dynamic hip function in children with cerebral palsy. This disruption is characterized by delayed and diminished peak knee flexion in swing phase. From a functional perspective, the quadriceps muscle group is actually two groups, the first consisting of the rectus femoris muscle and the second consisting of the triceps femoris muscles (remaining three muscles). The muscles typically exhibit a purely dynamic dysfunction during the first 6 years of life, characterized by a normal resting length and an exaggerated response to an applied load or stretch. With time, between 6 and 10 years of age, the muscles develop a fixed or myostatic shortening, resulting in a permanent contracture. The rectus femoris muscle is the only one of the quadriceps muscle group that is considered to be biarticular, as it crosses both the hip joint and knee joint. It has its origin on the anterior inferior iliac spine (direct head) and the innominate portion of the pelvis just proximal to the superior margin of the acetabulum (reflected head) and its insertion on the superior pole of the patella. The rectus femoris muscle fuses with the underlying vastus intermedius muscle several centimeters proximal to the superior pole of the patella. The rectus femoris muscle and the other three portions of the quadriceps muscle group envelop the patella to form the patellar tendon, which inserts on the tibial tubercle apophysis of the proximal tibia. The rectus femoris muscle has a relatively small physiologic cross-sectional area and a relatively large ratio of tendon length to muscle fiber length, indicating that it is designed for maximal excursion and diminished force generation. This may be associated with decreased velocity of hip flexion in the stance to swing phase transition and increased ankle plantarflexion in swing phase, called a "stiff" gait pattern. A thorough examination will include the prone rectus femoris test (also known as the Duncan-Ely test). A positive slow rectus test indicates fixed shortening of the rectus femoris muscle. A positive fast rectus test indicates the presence of spasticity of the rectus femoris muscle. A poor transition at the hip is characterized by decreased flexion range and velocity and is a contraindication to rectus femoris muscle transfer. This circumstance is a contraindication for transfer of the rectus femoris muscle. Leg-length inequality, when the reference limb is relatively short or the contralateral lower extremity is relatively long. In this situation, there is less need for functional shortening of the reference limb in swing phase. Sagittal plane knee (A) and hip (B) kinematic plots of a child with a jump gait pattern. The gait cycle appears on the horizontal axis, the direction of motion on the vertical axis. Kinematic indicators for transfer of the rectus femoris muscle are delayed and diminished peak knee flexion in midswing phase (circle), and decreased range and rate of knee flexion in the stance to swing transition (arrow). The kinematic contraindications at the hip for transfer of the rectus femoris muscle at the knee are decreased range and rate of hip flexion in the stance to swing transition (arrow). The stance and swing phases of each cycle are separated by the dashed black lines. The normal timing of activation of the muscle is noted by the horizontal red lines at the bottom of the strip. A tourniquet is placed about the most proximal portion of the thigh, and the extremity is carefully cleansed and draped to allow adequate exposure for the surgical approach to the rectus femoris muscle. The dissection is carried down through the subcutaneous layers to the fascia overlying the quadriceps muscle group. This fascial layer is incised for the full length of the incision, exposing the myotendinous portion of the rectus femoris muscle proximally and the superior pole of the patella distally. The rectus femoris muscle is dissected from proximal to distal, freeing it completely from the surrounding quadriceps muscle group. The rectus femoris muscle is separated from the other muscles of the quadriceps muscle group proximally (arrow). Mobilization of the rectus femoris distally from its insertion on the superior pole of the patella (circle). This tunnel should be superficial to the quadriceps fascia and deep to the majority of the subcutaneous fat of the medial thigh, and expanded to a width of two fingerbreadths. Tension is applied to the rectus femoris tendon using the transfer suture, and the line of pull of the rectus femoris muscle is assessed beneath the proximal margin of the anterior thigh incision. Further proximal release may be necessary to optimize the line of pull of the rectus femoris muscle in its transferred position. The rectus femoris muscle is manipulated using the transfer suture (dashed arrow) and released proximally using the scissors (solid arrow). Orientation of the transfer tunnel between the medial and anterior skin incisions (red arrow). A clamp is placed into the tunnel from distal medial to proximal anterior and used to guide the rectus femoris muscle­tendon unit to its site of transfer insertion (circle). The rectus femoris tendon is delivered into the medial incision (solid circle), where it will be transferred to the distal portion of the semitendinosus muscle tendon (dashed circle). The transfer is tensioned so that the muscle belly of the rectus femoris muscle is slightly tighter to palpation than the muscle bellies of the remaining three muscles of the quadriceps muscle group, when the knee is held in full extension. When gait velocity is diminished beyond 70% of normal, poor hip flexor function in the stance to swing transition is present, or there is an anatomic or functional leg-length inequality (reference limb short), delayed and diminished peak knee flexion in swing phase will not be improved by transfer of the rectus femoris muscle. The rectus femoris muscle is a biarticular muscle and should be transferred to another biarticular muscle (such as the semitendinosus). The line of pull of the transferred muscle­tendon unit should be as straight as possible. The long anterior thigh incision and intermuscular proximal release of the rectus femoris muscle must be performed. Adequate release of the rectus femoris muscle cannot be achieved through a small incision. The transfer tunnel for the rectus femoris muscle should be at the level of the subcutaneous fat, superficial to the quadriceps fascia. The muscle transfer should be tensioned so the muscle belly is at a slight stretch, to optimize the length­tension relationship of the transferred muscle. The rectus femoris muscle transfer should be tensioned so the muscle is slightly tighter than the other portions of the quadriceps muscle group. If complete knee extension has been achieved after lengthening of the medial hamstring muscles and transfer of the rectus femoris muscle, then the knee is protected in a knee immobilizer after surgery. The knee immobilizer is worn full time and the child is kept non-weight bearing for 2 weeks. This should be corrected by appropriate gait training early in the rehabilitation phase. Improved dynamic alignment at the knee during the swing phase of the gait cycle should result in improved gait efficiency and clearance of the swing limb. Improvements in swing-phase knee kinematics after rectus femoris muscle transfer have been documented at 1 year after surgery and have been shown to be maintained at 5 and 10 years of follow-up. Proper rehabilitation under the direction of an experienced physical therapist is effective in managing this problem. The principal cosmetic complication after transfer of the rectus femoris muscle is an unsightly scar that may develop at the incision site on the anterior aspect of the thigh. This is a consequence of the preferred incision crossing the skin lines of Langer. Scar formation is minimized by proper incision wound management (pressure applied by massage) during the postoperative rehabilitation phase. Prediction of outcome after rectus femoris surgery in cerebral palsy: the role of cocontraction of the rectus femoris and vastus lateralis. Diminished knee flexion after hamstring surgery in cerebral palsy: prevalence and severity. Force and moment generating capacity of the lower extremity muscles before and after tendon lengthening. Knee motion following multiple soft tissue releases in ambulatory patients with cerebral palsy. Treatment of stiff-knee gait in cerebral palsy; a comparison of distal rectus femoris transfer versus proximal rectus release. Propulsive function during gait in diplegic children: evaluation after surgery for gait improvement. Based on modeling studies, the hamstrings are a significant contribution to increasing the force in spastic hip disease, which causes hip subluxation. They are also a component that keeps the knees flexed and secondarily encourages flexion combined with spastic hip flexors, which causes the knee to fall into internal rotation and adduction, magnifying the influence of the concomitant spastic adductors. This posture of hip flexion and internal rotation and adduction, with the addition of high muscle force, tends to drive the hip posterosuperiorly out of the acetabulum.

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