Introduction                       

As the costs of healthcare continue to rise and the burdens of hospitalization increase, both to the healthcare system and the healthcare consumer, there is an argument to be made for the increasing role of truly outpatient total joint arthroplasty. Joint replacement has historically been associated with a seven to ten day hospitalization often followed by inpatient rehabilitation. However, over the last 10 years in many joint replacement centers, there has been a movement towards shorter hospitalizations which has been facilitated by improvements in surgical techniques, more sophisticated pharmacologic regimens to control nausea and pain, and modification of postoperative physical therapy pathways to allow a more rapid return to normal activities.

Our center’s experience with minimally-invasive surgery began in 1996, at which time our center, along with several centers across the United States, began to investigate minimizing approaches in total hip arthroplasty. A “mini-incision” approach was developed in 1996 and over the years the technique was improved so that it is now routinely performed through an incision size of 6.5-9 cm. Multiple surgical techniques and strategies as well as instruments were modified as this experience developed. The concept of the “mobile window” was developed in which the surgical wound is moved over the limb and the limb moved under the surgical window throughout the case to allow visualization of the surgical anatomy germane to that particular portion of the procedure. The surgical assistant began to assume a much more active and important role during the procedure. Specialized instrumentation for tissues retraction, osseous preparation, and component insertion were developed to maximize surgical exposure while minimizing surrounding tissue damage.

We reviewed our initial experience with the mini-incision posterior approach in 2004 and reviewed a series of 100 consecutive total hip arthroplasties performed in 98 patients between January 1998 and July 2002.1 The mean incision length in this group was 7.26 cm with a range of 6-8 cm and the average surgical time was 37.5 minutes. Complications in this cohort were minimal and not surgically related: one case of angina, one case of atrial fibrillation, and four DVTs in the perioperative period. There were no dislocations, nerve palsies or infections in this group. Most notably, patient length of stay was reduced to an average of only 2.89 days which was a dramatic reduction at our facility.

In 2001, our center’s next step with minimally-invasive hip surgery was the two-incision total hip arthroplasty. The original concept of this approach was that of Dana Mears and others, and the first case was performed by Dr Richard Berger at Rush Presbyterian in Chicago in February 2001.2,3 However, the two-incision total hip replacement was a procedure that was identified as being very technically demanding with a long learning curve,4,5

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requiring a great deal of tactile input and intraoperative fluoroscopy in lieu of direct visualization, and more active assistance from the surgical team. In our first 255 patients, there were three intraoperative femoral fractures, one dislocation, one deep posterior hematoma requiring drainage, and two lateral femoral cutaneous nerve palsies which were partial. In the follow-up period, one patient developed significant heterotopic bone and there were other rare complications not relating to the procedure, including urinary retention in two cases. One case required revision for subsidence. While the procedure is demanding and associated with certain complications not as frequently seen in other approaches, it was the two-incision movement that drove the development of perioperative techniques and protocols that facilitated a more rapid recovery and often allowed patients to be discharged from the hospital the day of surgery. In fact, the greatest limiting factor to same day discharge was, and still is, providing the patients with enough nursing attention and physical therapy to allow patients to be safely discharged from the hospital.

Our impression, after comparing the two-incision to the mini-posterior approach was that the mini-posterior approach had several advantages, including being easier to learn, more extensile, had significantly less blood loss, and did not require intraoperative imaging. With that in mind, we began our initial ambulatory surgical center experience in June 2008 with the goal of performing same day outpatient total joint replacement for appropriately selected surgical candidates.

 

Total Hip Arthroplasty

 

Requirements for Outpatient Total Joint Arthroplasty

 

Ambulatory TJA must be performed in either a hospital or ambulatory surgical center (ASC) with fully equipped operating rooms. We perform outpatient surgery in a three room ASC and typically run two rooms with two separate surgical teams and anesthesiologists to maximize efficiency. The number of procedures performed in a day is limited to four or five and all procedures are completed by noon. This ensures that patients have enough time to recover from anesthesia and complete physical therapy so that they may be safely discharged by early evening. While the ASC has “23 hour” capabilities, no patient has needed to spend the night at the center. The ASC has full service radiology with both conventional and fluoroscopic capabilities readily available in the event of any intraoperative complication and for routine postoperative X-ray. A physical therapy unit is present in the facility to provide intensive postoperative physical therapy for our patients which begins as soon as sensation and motor strength has returned to the lower extremities. The ASC has also developed a working relationship with multiple venders to allow for the timely delivery, maintenance, processing, and servicing of the equipment and implants needed in TJA. The ASC also has ample storage facilities, a full service central processing center, and large autoclaves essential for sterilization of the multiple large trays required for arthroplasty. A working relationship with a blood bank was also established, so that, if desired, patient may predonate autologous blood.

In order to perform outpatient total hip replacement it is important to coordinate the necessary physical therapy and nursing services that the patients will need upon discharge from the ASC. These arrangements are made well in advance of surgery through a discharge planner at the ASC. Patients begin home physical therapy the day after surgery and continue this until they are ready to begin outpatient therapy, typically at one to two weeks postoperatively. Patients are generally immediately weight bearing as tolerated and transition from crutches or a cane to unaided gait as soon as they feel comfortable. Visiting nurse services are also necessary and patients are routinely seen by a visiting nurse on the first postoperative day and then daily thereafter until such care is no longer needed.

Frequent office contact is necessary in the perioperative period and it is routine for the surgeon to contact their patients the evening of surgery and the following morning to ensure that there are no problems and to answer patient or family questions or concerns. Often the

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Table 41.1: Preoperative protocol

Table 41.2: Perioperative protocol

 

• Celecoxib 400 mg po

• Oxycodone with acetaminophen (5 / 325 mg)—2 tabs po

• Famotidine 20 mg IV

• Pregabalin 100 mg po

• Scopolamine transderm patch (1.5 mg)

  • +/– Oxycontin 10 or 20 mg po

• Metaclopramide 10 mg IV

• Ondansetron 4 mg IV

• Dexamethasone 8 mg IV

  Total Hip Replacement in an Ambulatory Surgical Setting

   

• Appropriate antibiotic

   

   

   

   

  patients return to the office for a wound check on post-op day 2. Subsequent patient contact is as needed prior to the two week follow-up.

  To facilitate a successful ambulatory surgical experience, the analgesia and anti-nausea protocols must be developed to allow early patient mobilization, physical therapy participation, and timely discharge. These can be divided into preoperative, perioperative, postoperative, and outpatient protocols.

   

  PREOPERATIVE (TABLE 41.1)

  In the holding room prior to surgery one unit of whole blood is taken from the patient to be returned to them in the OR at the conclusion of the surgery. This volume is replaced with normal saline or lactated ringers to maintain the intravascular volume but with a diluted red cell mass. Such “acute normovolemic hemodilution” is well supported in the literature to reduce postoperative allogenic and autologous transfusions.6,7 We have also found that it provides patients with vigor and helps to reduce postoperative hypotension. While we do not have patients routinely predonate autologous blood, some have elected to do so and this is also returned at the conclusion of surgery. This may also be effective at minimizing postoperative syncope. Patients are also given a “cocktail” of medications listed in Table 41.1 to pre-emptively control pain and nausea.

   

  PERIOPERATIVE (TABLE 41.2)

  In the operating room, prior to the procedure, the patient receives metoclopramide, ondansetron, and dexamethasone to help control postoperative nausea. They are also given an appropriate antibiotic prior to surgical incision. The antibiotic is continued at the appropriate interval in the recovery room. Patients are given an equivalent oral antibiotic to take at home to complete the traditional, and now Surgical Care Improvement Project (SCIP) mandated perioperative antibiotic coverage.

  Foley catheters are not routinely used as the rapid recovery from the anesthesia and early mobilization have made urinary retention an infrequent event. Patients are given warmed IV fluids to control volume and, along with a forced air warming device, to prevent hypothermia. A thigh length anti-embolic stocking and a pneumatic compression device are placed on the nonoperative leg prior to surgery to help reduce the risk of VTE. The patient is also given 1000 to 1500 units of heparin as an IV bolus prior to incision. The surgery is done under spinal anesthesia, usually with hypobaric bupivacaine, or other short acting agents at the discretion of the anesthesiologist to allow rapid motor and sensory recovery and early mobilization. The patients are also appropriately sedated for the procedure. During surgery, hypotensive anesthesia is used to minimize bleeding and meticulous hemostasis is maintained. At the conclusion of surgery the periarticular soft tissues and subcutaneous tissues are locally infiltrated with 1 cc per kg of patient body weight with 0.25% bupivicaine with epinephrine (1:200,000). Reinfusion drains are routinely used as part of the blood management protocol.

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  POSTOPERATIVE

  Total Hip Arthroplasty

   

  In the recovery room the patients are kept warm, receive the remainder of the blood removed for acute normovolemic hemodilution , and, if they pre-donated blood, their autologous unit as well. They also receive the blood collected in the reinfusion drain. Prior to discharge, the drain is removed by the recovery room nurses. IV fluid is continued until the patient is able to tolerate good oral intake. A thigh length anti-embolic stocking and a pneumatic compression device is placed on the operative leg to prevent venous stasis. Ice or a self-contained cryotherapy unit is placed over the surgical site to control local swelling. Postoperative pain and nausea are controlled with oral pain meds and IV ondansetron .

  Two of the most important components of effective ambulatory TJA are the postoperative nursing and physical therapy that the patients receive. At the ASC the patients receive oneon-one nursing which allows the patient to have the complete focused attention of a healthcare professional as they recover from the anesthesia and begin to mobilize. In this way the needs of the patient are immediately met so that the sequela of pain, nausea, and hypotension are not allowed to progress. Similarly, as soon as the anesthesia has worn off and the patient has had something to eat they begin to work with a physical therapist and have several sessions throughout the day. The first session consist of transfers and protected ambulation. Later sessions focus on independent ambulation and stairs if the patient needs to negotiate these at home.

  Prior to discharge, the patient is given their last dose of IV antibiotics and warfarin 10 mg for VTE prophylaxis. The nurses also review the postoperative instructions and medications (Table 41.3). The patients leave by regular car. From the ASC patients take with them the cryotherapy unit, the hip abduction pillow if ordered, the anti-embolic stockings and any necessary ambulatory aides.

   

  AT HOME (TABLE 41.3)

  Once the patient gets home there is frequent contact from the office to answer any questions and discuss any concerns regarding their care or treatment plan. The surgeon or their assistants typically call the patient at home both on the evening of surgery and again the following morning. Patients often return to the office on the second postoperative day for a wound check and to personally review their care. The patients also have daily visits from a visiting nurse who monitors the patient’s progress, changes the surgical dressing if necessary, reviews the proper use of the postoperative medications, and contacts our office with any concerns.

  Ten mg of warfarin is given on the day of surgery and then 5 mg on postoperative day one for DVT prophylaxis. For patients not chronically on warfarin, on postoperative day 2 the warfarin is discontinued and enoxaparin 40 mg daily is started. Initially enoxaparin was

   

  Table 41.3: Home medications

   

  • Cefalexin (to take as their last dose of Abx within 24 hours of surgery)

  • Warfarin 5 mg po to be taken Postop day #1

  • Enoxaparin 40 mg SQ daily for 10 days to start Postop day #2

  • Oxycontin 10 mg po q12 for 14 days PRN

  • Percocet (3/325) 1-2 tabs po q4 hours PRN breakthrough pain

  • Celebrex 200 mg po BID for 6 weeks (may substitute indomethacin 25 mg po TID for 10 days for heterotopic ossification prophylaxis)

  • Pregabalin 50 mg po q12 for 2 weeks

  • Famotidine 20 mg po daily for 2 weeks

  • Docusate 100 mg po TID as needed

  • Ferrous sulfate 1 tab TID for 6 weeks

 

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started the day of surgery but it was found that the surgical wounds had some serous drainage which was attributed to the combination of rapid mobilization and enoxaparin. Serous wound drainage has not been a problem since switching to warfarin on the day of surgery and postoperative day one. The patients continue the anti-embolic stocking for the first 6 weeks postoperatively. Typically, they wear the stockings during the day and remove them while sleeping.

The patients begin home physical therapy on postoperative day one and continue therapy five days a week for the first two weeks. At the two week follow-up visit the patient is transitioned to outpatient physical therapy which they continue until they have met their therapy goals and are discharged to a home program.

 

Surgical                    Technique                    

PATIENT POSITIONING AND LANDMARKS

The patient is positioned on a standard operative table in a lateral decubitus position with the surgical side up and is secured firmly in position with any one of several commercially available hip holding devices. The device must firmly secure the pelvis and allow for free range of motion of the affected limb and accurate assessment of the pelvic position and orientation. Because malposition of the operative table or hip holding device can affect component position we use a carpenter’s level to ensure that both the table and hip positioner are parallel to the floor and that the pelvis is perpendicular to the floor. Once the patient is secured in the hip positioner one should palpate the frontal plane of the pelvis, as defined by the two anterior-superior iliac spines and the pubic symphysis, to better understand the position of the pelvis and to make surgical adjustments to ensure proper acetabular component positioning. Any degree of forward roll of the pelvis should be avoided as it both compromises acetabular exposure and tends to bias acetabular cup positioning towards retroversion. It is important to keep in mind that most of the standard pelvic holding devices place the pelvis in up to 20 degrees of forward flexion and therefore require a corresponding modification in acetabular reaming and component positioning so as to obtain appropriate acetabular version.

As is true for all techniques of total hip arthroplasty, the most accurate method of restoring proper leg length and offset is by meticulous preoperative templating of the anterior-posterior (AP) and lateral X-rays of the patient’s pelvis and affected hip. With minimally invasive THA, the importance of accurate preoperative templating cannot be overly emphasized. During the templating process a surgeon must be cognizant of their bias with respect to acetabular cup position and make sure that the preoperative plan reflects this bias so as accurately restore the head center, and overall length and offset. Similarly, reproducible reference points for the femoral neck osteotomy must be established to accurately restore length and offset. Both the lesser trochanter and the superior femoral neck border with the medial wall of the greater trochanter (i.e. the greater trochanteric shoulder or saddle) are readily available reference points on which to locate the depth of the femoral neck osteotomy. Standard intraoperative neck cutting guides may be easily used with this minimally invasive technique. In minimal incision total hip arthroplasty precise location of the incision is of critical importance; a poorly located incision will have tremendous repercussions on the visualization of the hip joint, as well as, instrumentation and component positioning. It is important to drape out a wide field well above the iliac crest to facilitate palpation of both bony and soft tissue landmarks that guide incision location (Fig. 41.1). The true high point of the pelvis (i.e. the point at which the lumbar paraspinal muscles meet the lateral border of the posterolateral ileum) generally can be palpated in most patients who are candidates for minimally invasive total hip arthroplasty. This point is marked and a line approximately two fingerbreadths posterior to the high point of the pelvis and directed toward the center of the greater trochanter, is marked. This second point generally represents a good approximation

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Total Hip Arthroplasty

 

Figure 41.1: Proper placement of incision is critical for mini-incision THA. The incision is generally located just posterior to the mid-portion of the greater trochanter and is angled parallel to a line directed towards the greater trochanter starting approximately two centimeters posterior to the high point of the iliac crest

 

of the acetabular anteversion angle. The superior, anterior and posterior edges of the greater trochanter are next identified. If difficulty is encountered in identifying the greater trochanter, a 20 gauge, 3.5 inch spinal needle may be used to palpate and confirm the precise location of the greater trochanter. A slightly oblique incision is marked, directed parallel to the anteversion angle previously identified. This incision is typically oblique and directed posteriorly 10 degrees to 20 degrees with respect to the long axis of the femur, usually measuring 7 to 8 cm in length with approximately 80% of the incision distal to the superior edge of the greater trochanter. The incision is centered slightly (approximately 5 mm) posterior to the midline of the proximal femur. It is moved posteriorly as the thickness of the lateral adipose tissue increases. One must avoid excessive posterior translation as this will greatly compromise visualization of the anterior acetabulum.

With experience, the location of the incision can be modified based on the patient’s skeletal anatomy and body habitus. In patients who have more adipose tissue, the incision is translated proximally 1 cm to minimize superior wound compromise during femoral canal exposure and preparation. In patients with Crowe I-II hip dysplasia or significant lateral subluxation caused by large medial wall osteophytes, the incision is translated distally. In cases of substantial lateral subluxation, the entire incision may extend distally from the most proximal border of the greater trochanter.

 

PATIENT EXPOSURE

Once the skin incision has been made, the subcutaneous tissue is divided in the line of the incision. The gluteus maximus fascia and fascia lata are identified. It is important to not undermine the adipose tissue off of the deep fascia. Doing so not only places at risk the vascularity of the skin and subcutaneous fat, it also creates a dead space that may allow for the formation of a seroma or hematoma which could compromise the integrity of the wound. These deep fascial structures are incised in the direction of their fibers. The gluteus maximus muscle is bluntly split. If the fascial opening is too tight, the fascial incision may be extended one centimeter distal to the inferior pole of the skin incision. Proximal extension of the fascial incision beyond the proximal pole of the skin incision is rarely required. A modified Charnley retractor designed to minimize tension on the skin edges and soft tissues while providing maximal visualization is then placed into the wound. These modifications include both a lengthened anterior arm as well as radialized blade edges that match the contour of the retracted skin edges of the shortened incision (Fig. 41.2). Occasionally, a deeper posterior blade is necessary for patients with more adipose tissue or well developed gluteal musculature.

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Total Hip Replacement in an Ambulatory Surgical Setting

 

Figure 41.2: Modified Charnley retractor with an elongated anterior arm and curved blades to minimize tension on the skin edges

Figure 41.3: The short external rotators and posterior hip capsule are seen posterior to the greater trochanter

 

The surgical hip is brought to a position of neutral to slight extension, gravity assisted adduction, and lightly forced internal rotation. This position places on tension the short external rotators and posterior hip capsule and moves the surgical field well away from the sciatic nerve. The trochanteric bursa, pericapsular fat, short external rotators and posterior hip capsule are not separated from each other during this portion of the dissection. By not surgically separating these structures, the tendons of the piriformis and conjoined tendon of the superior and inferior gemelli and obturator internus tend to remain adherent to the edge of the capsular flap and allow for a more robust closure of this layer at the conclusion of the procedure. The border between the piriformis and gluteus minimus is identified and a Cobb elevator may be placed to gently elevate the posterior edge of the gluteus minimus off of the posterior-superior hip capsule. The tip of the electrocautery is gently bent to facilitate its reach behind the posterior greater trochanter onto the piriformis fossa. The short external rotators and underlying hip capsule are then released as one continuous sleeve from the piriformis fossa and posterior femoral neck with electrocautery (Fig. 41.3). This is done in the standard “hockey-stick” fashion, first along the superior edge of the piriformis tendon from the acetabular rim to the piriformis fossa, and then extending distally to release the conjoined tendon and posterior hip capsule

The hip is atraumatically dislocated posteriorly in slight flexion (approximately 15 degrees), adduction and internal rotation. The location for the femoral neck osteotomy is identified as preoperatively templated and is easily referenced off of either the lesser trochanter or superior neck-greater trochanteric junction. To facilitate visualization of the lesser trochanter the hip is brought into extension and a blunt Cobra retractor may be placed just distal to the lesser trochanter. Occasionally, the upper edge of the quadratus femoris must be released to visualize the upper portion of the lesser trochanter. Care should be taken to avoid releasing more distally into the quadratus femoris as bleeding may be encountered. There should be ample room to place a neck cutting guide if desired.

The femoral neck osteotomy is then made with a reciprocating saw with cutting teeth only on one side (Fig. 41.4A). This is a critical instrument for use in this procedure because its design protects against inadvertent injury to the posterior structures including the sciatic nerve. As the femoral neck is osteotomized from the medial calcar towards the greater trochanter, it is important that the first assistant gradually flexes the hip. This brings the greater trochanter into direct visualization within the mobile window and avoids accidental

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Total Hip Arthroplasty

 

Figures 41.4A to C: (A) The femoral neck osteotomy is performed with a single sided reciprocating saw blade to minimize risk to surrounding soft tissues. The first assistant may gently flex the hip during the osteotomy to facilitate visualization of the femoral neck. The osteotomy is opened with hip extension (B) and the femoral head removed (C)

 

trochanteric notching. The vertical limb of the neck cut then is made by starting proximally at the junction of the piriformis fossa and medial boarder of the greater trochanter and extending distally to the previous osteotomy. The hip is then brought back into extension. This generally rotates the femoral head into flexion and exposes the cut cancellous surface of the neck (Fig. 41.4B) facilitating removal of the femoral head which is easily grasped with a bone holding clamp (Fig. 41.4C). Difficulty may be encountered in removing large femoral heads or heads with massive peripheral osteophytes through the incision. In such cases the Charnley retractor may be relaxed or removed in entirety. This usually allows the femoral heads to be removed without need to extend the incision. Occasionally, in cases of severe protrusio or large osteophytes, an in situ femoral neck osteotomy may be necessary. The hip is returned to a neutral position after the femoral head has been removed and the height of the neck osteotomy has been confirmed.

 

ACETABULAR PREPARATION

It is important to understand that all parts of the acetabulum should be easily visualized throughout this procedure through the surgical incision. Using the concept of the mobile

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Total Hip Replacement in an Ambulatory Surgical Setting

 

window, different parts of the acetabulum can be highlighted through the differential relaxing and tightening of reciprocal acetabular retractors and by changing the position of the femur. For example, visualization of the anterior acetabulum is facilitated with gentle femoral flexion and slight internal rotation, pressure on the anterior acetabular retractor and relaxation of the posterior retractor while posterior acetabular visualization is facilitated with neutral limb position, relaxation of the anterior acetabular retractor and gentle pressure on the Kocher retracting the posterior capsular flap.

The anterior acetabular retractor is placed first. Many designs of these retractors exist. We prefer a long, curved Homan retractor with a pointed single tip and a radialized blade that fits against the arc of the retracted soft tissues and skin edges (Fig. 41.5A). Self-illuminating retractors may be used to focus light directly into the wound to aid with visualization. The hip is held in slight internal rotation and the anterior acetabular retractor is placed into the acetabulum. The surgical assistant then brings the hip into neutral rotation as the surgeon lifts the tip of the retractor up, through the anterior hip capsule and over the anterior wall and column of the acetabulum so as to retract the proximal femur anterior to the acetabulum.

It is critical to achieve adequate anterior exposure for later stages of acetabular preparation. In large, muscular men, difficulty may be encountered in retracting the proximal femur anteriorly. Inadequate femoral mobilization may result in proximal femoral fracture or anterior acetabular fracture from excessive pressure on the anterior acetabular retractor, eccentric reaming of the posterior acetabulum resulting in compromise of the posterior wall and/or column, or acetabular cup malposition into relative retroversion and/or excessive abduction. In such cases, the superior capsule may be released at the rim of the acetabulum. This usually allows for adequate proximal femoral mobilization. In rare cases where this does not provide adequate visualization, an anterior capsulotomy is performed by directing a scalpel blade, under direct visualization, beginning at the superior pole of the capsulotomy and continuing anteriorly and progressively inferiorly until adequate capsular relaxation is achieved. Generally, by the time an additional 90 degrees of hip capsule has been incised, the femur can be easily retracted anteriorly. Overzealous retraction of the proximal femur should not be necessary if the incision is properly located, the limb and retractors are appropriately positioned, and the capsular tissues sufficiently released.

A second retractor is than placed to retract the inferior hip capsule. We prefer to use a blunt Cobra retractor with a tip bent to 45 degrees (Fig. 41.5A). It is placed from within the acetabulum, deep to the transverse acetabular ligament, through the obturator foramen and

 

 

 

Figures 41.5A and B: (A) A blunt Cobra retractor with a 45 degree tip is placed below the transverse acetabular ligament and an anterior acetabular retractor with a curved blade is used to retract the femur anteriorly. A Kocher is used to control and retract the posterior hip capsule (B) allowing full acetabular visualization

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Total Hip Arthroplasty

 

Figure 41.6: Reamer sleeve in place to protect the inferior skin edge during acetabular preparation

 

hooked around the medial acetabular wall. If there are significant inferior acetabular osteophytes extending over or obliterating the transverse acetabular ligament and the inferior introitus to the acetabulum, they are removed with a rongeur or osteotome before the inferior retractor is be placed. A Kocher clamp is then placed on the posterior-superior corner of the capsular flap and is used to retract the posterior capsule during acetabular preparation. This clamp provides excellent visualization of the posterior acetabulum and obviates the need for placement of a large posterior retractor that could place posterior structures including the sciatic nerve at risk. With the anterior Homan retractor, the blunt Cobra retractor, and the Kocher clamp in place full visualization of the acetabulum should be achieved (Fig. 41.5B).

The pulvinar and medial wall osteophytes may be excised using a large curette or rongeur to reveal the true medial wall of the acetabulum. The acetabular labrum is resected by selectively tightening and loosening the anterior and posterior retractors to directly visualize the anterior and posterior components of the labrum. The remaining islands of acetabular cartilage may be removed with a large acetabular curette. The surgical assistant holds the anterior and inferior retractors. The posterior Kocher is controlled by the surgeon. The limb is allowed to lie dependent over the opposite leg. Acetabular reaming is then commenced, generally with the largest reamer that will bottom out in the patient’s socket. During the reaming process it is important to make sure that the reamer handle does not lever on the femur and bias the reamer posteriorly causing eccentric reaming, and ultimately, compromise of the posterior wall and column of the acetabulum. It is also important to ensure that the reamer sleeve is in proper position to protect the skin edge at the inferior pole of the incision (Fig. 41.6). Offset reamers may be used to minimize both soft tissue and bony impingement during acetabular preparation.

When inserting the acetabular component through the incision, the component should be introduced in retroversion so that it is oriented with its internal surface directed posteriorly and its external convex surface directed anteriorly (Fig. 41.7). It then is slid down along the internal radius of the anterior retractor to the level of the acetabulum and then is redirected into its appropriate position. This maneuver of utilizing the external convex geometry of the acetabular shell and orientating it to the internal concave geometry of the Charnley retractor blades is particularly important when inserting large diameter sockets in small incisions and avoids dragging soft tissue into the prosthetic/host bone interface. Before impacting the acetabular component into position great care should be taken to avoid the entrapment of soft tissue between the outer surface of the acetabular component and the prepared acetabular bone to ensure maximal prosthetic-host bone contact for osseousintegration.

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Figure 41.7: Acetabular component inserted in retroversion to facilitate passage through the incision and surrounding soft tissues

 

 

 

Figures 41.8A and B: A straight acetabular inserter may impinge on the inferior edge of the wound which could cause the cup to be placed in excessive abduction (A). Such impingement may be avoided with the use of an offset acetabular inserter (B)

The acetabular component is inserted with an ideal true abduction angle of 40 to 45 degrees and an ideal true anteversion angle of approximately 20 degrees.

While a standard acetabular inserter may be used with this approach (Fig. 41.8A) it may impinge on the inferior pole of the wound which may bias the final component position into an excessively vertical position. To avoid such impingement, a dogleg acetabular inserter may be utilized (Fig. 41.8B). The midportion of this inserter is designed to avoid soft tissue impingement at the wound edges and may greatly facilitate component positioning. The acetabular inserter is aligned to assure appropriate acetabular abduction and anteversion and is then struck firmly with a mallet to fully seat the cup (Fig. 41.9).

Anterior and inferior peripheral osteophytes are generally removed once the acetabular component has been inserted (Fig. 41.10). A 1.5 cm slightly curved osteotome is used to excise potentially impinging anterior and anteroinferior osteophytes after the acetabular shell has been impacted into position and prior to insertion of modular articular liners. Straight osteotomes generally are used to excise posterior and posteroinferior osteophytes.

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Total Hip Arthroplasty

 

Figure 41.9: The cup fully visualized and well seated in the acetabulum

 

 

 

Figure 41.10: Peripheral osteophytes are easily identified and removed with a curved osteotome under direct visualization

 

Visualization and excision of the posterior osteophytes is much easier if left until the trial femoral component is in place and the hip has been reduced as the posterior hip capsule is under tension unveiling these posterior structures.

Acetabular screws may be easily placed through the minimally invasive posterior incision If deemed necessary for additional acetabular fixation. Acetabular screw holes are readily seen, and using standard, flexible drill bits, drill guides, depth gages, and articulating screw drivers, the surgeon should be able to place screws without difficulty (Fig. 41.11).

For hip systems that call for the placement of a modular acetabular liner into the acetabular shell, this liner is now inserted and dialed into appropriate position before engagement into the locking mechanism of the acetabular component. It is important to ensure that no soft tissue is trapped between the acetabular shell and the liner. The liner is then impacted into position and locking is confirmed. The anterior and inferior retractors are removed and the Kocher clamp is removed from the posterior hip capsule.

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Figure 41.11: For additional fixation, screws may be placed under direct visualization

 

FEMORAL PREPARATION

The Charnley retractor is relaxed prior to preparation of the femur. This functionally lengthens the skin incision and reduces the risk of damage to the superior skin edges during reaming and/or broaching of the femoral canal. The nonoperative extremity is moved under the surgical drapes into a position of flexion with the knee at the edge of the operating table. The surgical assistant then presents the proximal femur into the wound by bringing the leg into a position of hip internal rotation, adduction, and neutral to slight flexion of approximately 10 degrees. The knee of the surgical extremity should sit just posterior to the nonoperative knee which remains flexed on the table. A specially designed femoral elevator is then placed under the anterior surface of the femur and is used to further present the proximal femur into the surgical wound. This retractor has a curved blade that fits within the contour of the superior skin edge. The design of this retractor not only reduces tension on the wound but also facilitates placement of femoral instrumentation while minimizing damage or abrasion to the superior and superoposterior skin edges. If damaged, the compromised skin should be trimmed prior to closure to avoid later wound compromise. With appropriate incision location, leg positioning, and the use of specially designed skin protector/femoral elevators, damage to the wound edges should be extremely rare.

With the proximal femoral elevator held in place by the surgeon or assistant, any remaining fibrous tissue, capsule, or piriformis tendon stump is removed from the area of the piriformis fossa to allow an unobstructed view of the proximal femur. The initial hand reamer or canal finder is positioned centrally and laterally into the cancellous bone of the femoral neck and directed down the femoral canal (Fig. 41.12A). If the body habitus is such that the initial canal finder cannot be passed straight down the femoral canal without impingement on the superior margin of the wound, then the proximal skin incision should be lengthened without hesitation. This is particularly important if a fully coated type of implant is being used so as to avoid skin abrasion and compromise of the wound edges.

A box osteotome or lateralizing reamer is used to remove any remaining lateral femoral neck that may direct the femoral broaches into varus (Fig. 41.12B). The femoral canal is now ready to be reamed and/or broached. Specially designed broach handles that have lower profiles and rounded edges are used to minimize impingement on the posterosuperior edge of the skin incision. However, there still remains a tendency for the proximal pole of the incision to apply a retroverting force onto the broach handle. As such, it is important to maintain rotational control of the broach handle. A Tommy bar may be placed through the

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Figures 41.12A and B: The femoral canal is first entered with a hand awl

(A) and then a box osteotome (B) or lateralizing reamer may be used to remove remaining lateral femoral neck to prevent varus canal preparation

 

 

 

Figures 41.13A and B: To prevent skin abrasion during canal preparation, the broaches are introduced in retroversion (A) until the cutting edges have cleared the superior skin edge and then the broach position is corrected to the appropriate femoral anteversion (B) before host bone is engaged

 

broach handle to maintain appropriate anteversion of the broach during femoral preparation. The avoidance of significant hip flexion during broaching is also important in minimizing impingement of the broach handles on the posterior-superior corner of the incision.

There are several ways in which the proximal pole of the skin incision is protected from broach abrasion during this portion of the procedure. One useful technique is to initially introduce the broach in retroversion (Fig. 41.13A). A major advantage of using a proximally coated, robustly tapered femoral component is that rotation of the rasp during the first several centimeters of its insertion has no effect on the final component interfaces. The broach is inserted in 60 degrees to 90 degrees of retroversion and as soon as its proximal teeth have moved beyond the proximal pole of the skin incision, the broach is rotated into its definitive anteversion (Fig. 41.13B). The proximal femoral elevator is also very useful to protect the superior pole of the wound during femoral canal preparation. The elevator is initially placed in its normal position, parallel to the long axis of the shaft of the femur until the broach has seated below the proximal margin of the skin wound. The elevator is then allowed to slide around the medial femoral neck so that its internal radius is placed between

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Figure 41.14: Modular stem in place prior to placement of modular neck and head

 

the medial edges of the broach/broach handle and the posterosuperior skin edges and thereby protect the proximal posterior corner of the wound from any incidental broach induced abrasion.

The femoral canal is prepared with successively larger broaches until an appropriate sense of fit and fill has been achieved and the broach has been demonstrated to be axially and rotationally stable at the level of the femoral neck osteotomy. In general, this broach should be roughly the same size as that predicted on the preoperative template. Once the definitive broach has been selected, a provisional reduction is performed with the trial femoral neck and head so as to fine tune leg length and offset. We frequently use a stem system that has a modular neck (Fig. 41.14) (Kinectiv Technologies, Zimmer Inc., Warsaw, IN). This design lends itself well to short incision surgery by allowing for seating of the broach and stem without impingement of the neck on the posterior soft tissues. This system also allows for the preparation of the femur independent of the neck. The neck anatomy and head center are then re-established with respect to length, offset and version with modular neck trials. When satisfied with the trial reduction, the trial components are removed, and a D and C curette is lightly applied to the prepared proximal femur to remove any soft tissue that may been inadvertently introduced during the broach process.

The final stem is then opened and pressed down the canal by hand and introduced initially, similar to the broach, in substantial retroversion to allow the neck to clear the posterosuperior skin edge (Fig. 41.15A). On occasion, particularly when placing a femoral component with a long or extended offset neck, difficulty may be encountered in getting the femoral neck to clear the posterosuperior skin edge and fascia. Bringing the limb into neutral abduction as well as extension relaxes the skin and fascia facilitating the reduction of the neck of the femoral component under these layers. For femoral components with modular necks, such maneuvers are rarely necessary as the final neck is placed after the stem is fully seated into the femur. Once the stem has been placed deep to the skin and fascia, final component rotation is achieved and the stem is impacted into final position and axial and rotational stability are confirmed (Fig. 41.15B).

Femoral head trials are then applied sequentially until appropriate leg length and hip joint tension and stability have been achieved. Leg lengths may be assessed using standard techniques including lining up the knees and ankles with the hips in neutral abduction, by push-pull testing to judge head shuck within the acetabulum, or by judging the relationship between fixed points on the proximal femur and pins firmly placed into the pelvis prior to

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Figures 41.15A and B: The femoral component is introduced in retroversion (A) to allow the neck to clear the superior skin edges and is then turned to the appropriate position prior to impaction and final seating of the implant (B)

 

 

 

Figure 41.16: A modified head impactor that avoids soft tissue impingement is used to seat the femoral head

Figure 41.17: Under direct visualization implant position and hip stability and range of motion are confirmed

 

the dislocation of the native hip. It the superior soft tissues prevent easy placement of the head trial on the femoral stem, side mounting head trials may be used as they allow for easier placement of the head trial over the Morse taper. Once the final head length has been selected the Morse taper is presented into the surgical wound with hip adduction, internal rotation, and neutral extension. The taper is cleaned and dried and the femoral head is struck once with a modified, offset head impactor that allows for firm impaction of the femoral head without compromise of the superior skin edges (Fig. 41.16). A final reduction is performed and hip range of motion, stability and leg lengths are confirmed (Fig. 41.17). The periarticular tissues and skin edges are injected with 0.25% marcaine with epinephrine to aide with postoperative analgesia.

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Figure 41.18: The posterior capsule and short external rotators are repaired to the greater trochanter through drill holes with suture

Figure 41.19: Typical mini-posterior surgical site after wound healing

An enhanced posterior capsular closure is then performed using number 1 Vicryl suture placed in a figure of eight fashion through the posterior-superior hip capsule and piriformis tendon at the point at which the radial and longitudinal portions of the capsulotomy meet. A second suture is placed approximately 1.0 to 1.5 cm distal to this through the posterior limb of the capsule and the conjoined tendon of the superior and inferior gemelli and the obturator internus. Drill holes are then placed through the greater trochanter into the piriformis fossa, taking care that the starting point is at least 1 cm below the tip of the trochanter and 1 cm anterior to the posterior boarder of the trochanter to avoid a stress riser and possible trochanteric fracture. Number 4 (22 gauge) surgical wire is then doubled over and placed through the drill holes to be used as suture passers. The free ends of the suture are then brought through the drill holes and are tied to each other with the limb in neutral rotation and 15 to 20 degrees of abduction (Fig. 41.18). A reinfusion drain is placed and the wound is closed in layers and the final dressing applied (Fig. 41.19).

 

HOW TO START

Patient selection is of paramount importance in beginning outpatient TJA. Patients must have a desire to be part of something new, a paradigm shift in how TJA are performed. They must have a clear understanding of the traditional environment of conventional TJA and how ambulatory surgery differs. We have found that patients who select ambulatory TJA are commonly motivated by a desire to stay out of the hospital and to undergo a rapid recovery program. Many of these patients are looking forward to not playing the part of a “patient” and returning to a normal lifestyle quickly. Patient education is very important and we spend considerable amount of time with each patient describing the procedure, explaining what they can expect and, just as importantly, what is expected of them throughout the perioperative period.8-10 It is imperative to select patients that are healthy and without significant medical comorbidiities that may make recovery difficult or result in perioperative medical complications. Initially, ideal patients to undergo ambulatory TJA are thin, young, and healthy with good bone stock, minimal arthritic deformity, avascular necrosis or Crowe I or II dysplasia. With experience patient selection may expand to include more challenging cases with respect to disease, deformity, and body habitus.

Pathways in the surgeon’s office must be created so that the surgical staff knows how to handle ambulatory patients and meet their unique needs. The anesthesiologists, nurses,

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physical therapists and staff at the ambulatory center need to know what is needed and expected of them in order to perform outpatient TJA. This comes through education and taking the time to develop clinical pathways that facilitate rapid patient mobilization and timely discharge from the center. Relationships with vendors must also be developed to ensure that the ASC has an adequate supply of equipment, streamlined instrument trays, and implants so that cases may be performed in an efficient manner.

 

Results                         

We performed our first ambulatory ASC THA on 6/30/2008 and have subsequently performed over 200 outpatient THAs. The age range of our patients is 22-69 with a mean of

54. These patients have a mean of one medical comorbidity with a range of 0-3. Our average surgical time is 43 minutes with a range of 31-68 minutes. We have experienced five major complications. There was one emergency room visit for an over-narcotized patient that required 6 hours of observation and an injection of naloxone, after which they were discharged home. There was one anterior hip dislocation in the recovery room which was immediately discovered. The patient was revised at the ASC that day and discharged home that same evening. There was another anterior dislocation in the first two weeks after surgery that was treated with an isolated cup revision. Two patients were taken to our main hospital for irrigation and debridements at two and three weeks postoperatively for draining hematomas. One patient had positive intraoperative cultures and was treated successfully with six weeks of intravenous antibiotics.

 

Conclusion                        

While the majority of our patients still undergo traditional THA in a hospital setting, ambulatory surgery is becoming an increasing part of our practice as patients are looking for a more rapid, streamlined and efficient total hip replacement. The actual technique that we use is familiar and converting this technique to outpatient surgery should be relatively simple for most surgeons. What is unique is the notion that total hip replacement may be safely and effectively performed on an outpatient basis. However, as cost constraints and patient demand for these procedures increases we predict that ambulatory THA in appropriately selected patients will become more common place.

 

References                       

1. Hartzband MA. Posterolateral minimal incision for total hip replacement: technique and early results. Orthop Clin North Am 2004;35:119-29.

2. Berger RA. Total hip arthroplasty using the minimally invasive two-incision approach. Clin Orthop Relat Res 2003;417:232-41.

3. Berry DJ, Berger RA, Callaghan JJ, Dorr LD, Duwelius PJ, Hartzband MA, Lieberman JR, Mears DC. Minimally invasive total hip arthroplasty. Development, early results, and a critical analysis. Presented at the Annual Meeting of the American Orthopaedic Association, Charleston, South Carolina. J Bone Joint Surg Am 2003;85:2235-46.

4. Archibeck MJ, White RE Jr. Learning curve for the two-incision total hip replacement. Clin Orthop Relat Res 2004;429:232-8.

5. Bal BS, Haltom D, Aleto T, Barrett M. Early complications of primary total hip replacement performed with a two-incision minimally invasive technique. J Bone Joint Surg Am 2005;87: 2432-8.

6. Oishi CS, D’Lima DD, Morris BA, Hardwick ME, Berkowitz SD, Colwell CW Jr. Hemodilution with other blood reinfusion techniques in total hip arthroplasty. Clin Orthop Relat Res 1997;339:132-9.

7. Goodnough LT, Despotis GJ, Merkel K, Monk TG. A randomized tria