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The Journal of Bone and Joint Surgery (American). 2005;87:1656-1666. doi:10.2106/JBJS.E.00364 © 2005 The Journal of Bone and Joint Surgery, Inc. What's New in Adult Reconstructive Knee Surgery1 New Mexico Orthopaedics, New Mexico Center for Joint Replacement Surgery, 201 Cedar S.E., Suite 6600, Albuquerque, NM 87106. E-mail address for M.J. Archibeck: archibeckmj{at}nmortho.net
Specialty Update has been developed in collaboration with the Council of
Musculoskeletal Specialty Societies (COMSS) of the American Academy of
Orthopaedic Surgeons.
The purpose of this update is to discuss, in summary fashion, topics presented at selected orthopaedic meetings and published in related orthopaedic journals during 2004. The sources for this review are articles published in The Journal of Bone and Joint Surgery (American edition) and The Journal of Arthroplasty. The podium presentations mentioned in this article include those given at the American Academy of Orthopaedic Surgeons (held in San Francisco, California, on March 10 through 14, 2004), on Combined Specialty Day at the meeting of the Knee Society (held in San Francisco, California, on March 13, 2004), at the interim meeting of the Knee Society (held in Jackson, Wyoming, on September 9 through 11, 2004), and at the annual meeting of the American Association of Hip and Knee Surgeons (held in Dallas, Texas, on November 5 through 7, 2004).
While total knee replacement has been very effective for alleviating pain and improving function in patients of all ages, other approaches remain the initial treatment for many patients with knee arthritis. The current role of nonsteroidal antiinflammatory drugs remains controversial because of new concerns regarding the elevated risk of cardiovascular complications associated with some of these medications. Clearly, their use should be carefully considered, especially for patients with preexisting cardiac or neurovascular risk factors. This decision should be individualized and, in many cases, the patient's medical physicians should be involved in the risk-to-benefit analysis. The American Academy of Orthopaedic Surgeons has issued a statement that physicians may want to consider therapies that provide protection for the stomach in addition to the pain relief provided by more traditional nonsteroidal antiinflammatory drugs (described on the AAOS web site [www.aaos.org], Your Orthopaedic Connection, Arthritis Section, "Use of Pain Medications, NSAIDs"). The role of intra-articular injection in the treatment of knee arthritis was addressed in two studies. Wind and Smolinski prospectively evaluated the reliability of superomedial, superolateral, and lateral joint line sites for the injection of low-volume (2 to 3-mL) injections typical of those used for viscosupplementation. The authors found that the lateral joint line injection site was least reliable, with a good intra-articular delivery of fluid occurring less than half the time. Wang et al. conducted a meta-analysis of twenty blinded, randomized, controlled trials that compared the therapeutic effect of intra-articular injection of hyaluronic acid with that of placebo and reported improvements in terms of pain and function, with few adverse events1. However, there was significant interstudy heterogeneity in the estimates of the efficacy of hyaluronic acid. In general, patients older than sixty-five years of age and those with the most advanced radiographic stage of osteoarthritis were less likely to benefit from the treatment. Autologous chondrocyte implantation of the patellofemoral articulation was reviewed by Minas in a study of forty-five patients. After a minimum duration of follow-up of two years, the rate of failure was 18% (eight knees) and the rate of patient satisfaction (as determined by whether the patient would choose the surgery again) was 87%. Two studies evaluated the role of osteotomy in the arthritic knee. Miller et al. retrospectively reviewed the records of sixty-one patients who had undergone a medial opening-wedge proximal tibial osteotomy and found a mean satisfaction score of 7.6 (with 1 indicating that the patient was not satisfied and 10 indicating that the patient was very satisfied) after a minimum duration of follow-up of two years. The mean Lysholm score improved significantly, from 49.9 preoperatively to 75.4 at the time of the most recent follow-up (p < 0.001), and it demonstrated no significant correlation with age, gender, fixation technique, or magnitude of correction. Tsumaki et al. found that low-intensity ultrasound, applied during the consolidation phase of distraction osteogenesis, accelerated callus maturation in a study of twenty-one patients who underwent bilateral one-stage opening-wedge proximal tibial osteotomy by hemicallotasis2.
With the recent interest in less invasive techniques and accelerated rehabilitation, several reports discussed advances in the treatment of perioperative pain. Ranawat and Ranawat reported on an "advanced perioperative pain management" protocol that included preoperative administration of Vioxx (rofecoxib) and oxycodone, administration of a spinal anesthetic with Duramorph (morphine), intraoperative injection of local tissues, and postoperative administration of Vioxx and Tylenol (acetaminophen). After six months of follow-up, the authors found that patients who had been managed with this technique had reduced narcotic requirements, reduced manipulation rates, and more rapid recovery of function and range of motion when compared with historical controls. Szczukowski et al. investigated the effects of a single-injection femoral nerve block with use of 0.5% bupivacaine with epinephrine in a study of forty randomized total knee arthroplasties (twenty with and twenty without femoral nerve block) and found significantly less morphine use (p = 0.003), a lower sedation scale (p = 0.045), and lower average pain perception (p = 0.002) in the group managed with the femoral nerve block3. The use of local injection was addressed in two studies. Lombardi et al. retrospectively compared 181 knees (138 patients) that had received no intraoperative injection during primary total knee arthroplasty with 197 knees (171 patients) that had been injected at the surgical site with bupivacaine with epinephrine and morphine. The authors reported improved pain control in the group that had received the injection as indicated by a lower requirement for breakthrough narcotics (p = 0.0278), a lower requirement for narcotic reversal, and lower blood loss (p < 0.0001). Browne et al. reported on sixty patients undergoing total knee arthroplasty who were randomized to receive a 20-mL injection of either bupivacaine (0.5%) or normal saline solution into the joint space after capsule closure. The authors reported lower pain scores, reduced narcotic usage, and a twenty-three-minute shorter time to discharge from the post-anesthesia unit in the bupivacaine group (p = 0.02)4. Breit and Van der Wall performed a randomized, blinded, placebo-controlled trial in which patients received patient-controlled analgesia only, patient-controlled analgesia plus transcutaneous electrical nerve stimulation, or patient-controlled analgesia plus sham transcutaneous electrical nerve stimulation. The authors reported no significant difference in narcotic requirements and concluded that transcutaneous electrical nerve stimulation had no utility in the treatment of postoperative pain after total knee arthroplasty.
Several studies reviewed a variety of modalities that are used to minimize patient exposure to allogeneic blood products following total knee arthroplasty. In an effort to identify current trends, Cushner et al. surveyed 433 active members of the American Association of Hip and Knee Surgeons and found that 60% routinely utilized autologous donation programs, 53% reported using epoetin alfa, and only 11% had tried using antifibrinolytics to reduce surgical blood loss. Bong et al. retrospectively reviewed 1402 primary total knee arthroplasties and found that the best predictors of allogeneic transfusion after surgery were advancing age (p < 0.001), a low preoperative hemoglobin level (p < 0.001), and the use of low-molecular-weight heparin postoperatively (p < 0.01)5. Nazarian and Booth enrolled 109 patients in a study evaluating the efficacy of epoetin alfa combined with and compared with preadmission donation and found that the preoperative use of epoetin alfa in conjunction with preadmission donation reduced the need for allogeneic blood transfusions to 11% (compared with 28% for epoetin alfa alone and 35% for preadmission donation alone). Dearborn reviewed his experience with the OrthoPAT device (Haemonetics, Braintree, Massachusetts), an automated cell-recovery system that allows intraoperative and postoperative blood collection. In his study of 830 patients undergoing total joint replacement, the author observed no complications and reported allogeneic transfusion rates of 5.7% for primary total knee arthroplasty, 9% for bilateral total knee arthroplasty, and 4.8% for total hip arthroplasty. Pierson et al. reviewed the records of 500 consecutive patients who had undergone primary unilateral total hip or total knee arthroplasty with use of a single blood-conservation algorithm involving selective use of epoetin alfa without preadmission donation and reported rates of allogeneic transfusion of 2.8% and 1.4%, respectively6.
With less invasive techniques and improved reported survival rates, unicompartmental knee replacement has become increasingly popular. One form of unicompartmental arthroplasty that has been associated with mixed results is the UniSpacer arthroplasty. Sisto, in a review of thirty-seven UniSpacer arthroplasties in thirty-four patients, reported no excellent results, ten good results, fifteen fair results, and twelve poor results (including six UniSpacer dislocations) after a mean duration of follow-up of eight months. All twelve knees with a poor result were revised. The author concluded that UniSpacer arthroplasty is not recommended for the treatment of medial compartment arthritis. More traditional unicompartmental arthroplasty has had more favorable results in appropriately selected patients. Gardner et al. reported on a series of 136 Marmor unicompartmental arthroplasties that were performed with cement in 103 elderly patients (mean age, 70.9 years) who were followed for a minimum of twenty-one years7. Nineteen knees were revised (twelve because of progression of disease and seven because of loosening) at a mean of 10.6 years. Of the nineteen knees with unicompartmental replacements that were followed for at least twenty years, 75% demonstrated disease progression and 20% demonstrated tibial subsidence or wear. Naudie et al. evaluated the mean ten-year results of 113 medial Miller-Galante unicompartmental arthroplasties (Zimmer, Warsaw, Indiana) and reported four revisions, with five and ten-year survival rates of 94% and 90%, respectively8. Berger et al. studied fifty-nine patients who had undergone unicompartmental arthroplasty and found that, by fifteen years, 10% of patients had patellofemoral symptoms and 26% had radiographic signs of patellofemoral osteoarthritis, with two patients requiring revision to total knee arthroplasty because of pain. Emerson and Higgins reviewed their series of fifty-nine medial Oxford mobile bearing unicompartmental arthroplasties (Biomet, Warsaw, Indiana) and reported no bearing dislocations, one case of femoral loosening, and four revisions because of arthritic progression after a minimum duration of follow-up of ten years. With regard to fixation, Manley et al. studied 113 consecutive hydroxyapatite-coated unicompartmental knee arthroplasties and reported no revisions and one case of reactive tibial radiolucent lines at a mean of 6.9 years of follow-up. Tabor reported the five to twenty-year results of ninety-three consecutive medial unicompartmental arthroplasties in seventy-six patients and identified twelve failures in ten patients at a mean of seventy-four months. There was no difference between patients who were more or less than sixty years of age and there was equal or improved prosthetic survival among obese patients. Unicompartmental knee arthroplasty lends itself to less invasive techniques. Tria studied fifty-seven patients who had undergone sixty-three unicompartmental arthroplasties that had been performed with a small-incision technique and reported one nondisplaced tibial plateau fracture, one revision for the treatment of a subluxating patella, and two knees with nonprogressive tibial radiolucent lines after a minimum duration of follow-up of two years. Muller et al. compared thirty-eight unicompartmental arthroplasties (Oxford; Biomet, Warsaw, Indiana) that had been performed through an open approach with thirty unicompartmental arthroplasties that had been performed through a minimally invasive approach and found improved functional results and Hospital for Special Surgery scores (92 compared with 78) in the group managed with the less invasive approach, with no adverse effect on radiographic component positioning. Lombardi et al. reviewed seventy-nine unicompartmental arthroplasties (including forty-eight procedures with instrumentation and thirty-one procedures without instrumentation) that had been performed with use of less invasive techniques and reported thirteen failures (six due to tibial loosening, two due to plateau fractures, three due to persistent pain, and two due to infection) at a mean of thirty-four months of follow-up. The authors concluded that if obesity (as indicated by a body-mass index of >32) and plateau fractures were excluded, reliable results could be obtained. The role of the anterior cruciate ligament in unicompartmental arthroplasty was the topic of several studies. Hernigou and Deschamps reviewed the mean sixteen-year results of ninety-nine unicompartmental arthroplasties in which the anterior cruciate ligament had been intact (fifty knees), damaged (thirty-one knees), or absent (eighteen knees) at the time of implantation9. They found that higher degrees of posterior slope were associated with a higher failure rate, especially in the absence of an intact anterior cruciate ligament, and concluded that posterior tibial slope of >7° should generally be avoided. Suggs et al., in an in vitro robotic study of unicompartmental arthroplasties in cadaveric knees, found that a medial unicompartmental arthroplasty did not alter the anterior stability of the knee but that a functioning anterior cruciate ligament is necessary to ensure normal stability. Price et al. compared the in vivo sagittal kinematics of the Oxford mobile-bearing unicompartmental replacement (Biomet, Warsaw, Indiana), a fixed-bearing total knee replacement, and the normal knee with use of dynamic fluoroscopy and found that the unicompartmental replacement preserved normal sagittal plane kinematics, implying that anterior cruciate ligament function was preserved at ten years10. Polyethylene wear remains a common mode of failure after unicompartmental knee replacement. Collier et al. reviewed 100 unicompartmental arthroplasties after a mean duration of follow-up of eight years and found the six-year survival rate to be 96% when the shelf age of the polyethylene was less than the median shelf age (1.7 years) and only 71% when it was greater than the median shelf age, suggesting that polyethylene that is sterilized by gamma irradiation in air is susceptible to accelerated fatigue failure with longer shelf life11. Price et al., in an in vivo study of seven patients who had had a unilateral fully congruent mobile-bearing unicompartmental arthroplasty, investigated polyethylene wear with use of radiostereometric analysis and found an average linear penetration of 0.25 mm after a mean duration of follow-up of 10.9 years (resulting in a linear wear rate of 0.02 mm/year).
While the clinical results of total knee arthroplasty continue to be excellent, debates regarding the superiority of various fixation techniques and differing designs continue. Duffy et al. studied seventy-two primary cemented total knee replacements in fifty-three patients who were fifty-five years of age or younger and reported survival rates of 96.7% and 92.2% at fifteen and twenty years, respectively. Colwell et al. studied the fourteen to seventeen-year results of 156 cruciate-retaining Press Fit Condylar total knee arthroplasties (PFC; Johnson and Johnson, Raynham, Massachusetts) and reported a survival rate of 91.9% with revision for any reason as the end point. Wright et al. reviewed the minimum ten-year results of 523 Kinemax total knee arthroplasties (Stryker, Allendale, New Jersey) and found a survival rate of 96.1% at ten years with revision for any reason as the end point. Maruyama et al. performed a prospective, randomized comparison of twenty patients undergoing bilateral total knee arthroplasty with a posterior stabilized design on one side and a cruciate-retaining design on the other. The authors found no differences in knee scores at a mean of thirty-one months but reported a superior range of motion in the posterior stabilized group. Aebli et al. studied the results of 134 cementless low contact stress mobile meniscal bearing total knee arthroplasties after a mean duration of follow-up of 7.5 years and reported that radiolucent tibial lines were nonprogressive in 99% of the knees that had such lines and that no revisions had been performed for the treatment of loosening. Cross and Parrish reviewed 1000 patients who had undergone a primary total knee arthroplasty with hydroxyapatite-coated components and found a 0.5% rate of revision (with only one revision performed because of aseptic loosening) at a mean of 6.6 years. Mobile-bearing total knee replacements received much attention this year. Dennis et al. studied the in vivo kinematics of mobile-bearing total knee replacements (including posterior-cruciate-retaining, posterior stabilized, and posterior-cruciate-sacrificing devices) and found that, in all designs studied, the polyethylene bearing rotated and translated relative to the tibial tray. Catani et al. studied eleven patients with use of fluoroscopic three-dimensional analysis and found relatively small amounts of motion of the mobile bearing (mean, 3.8°) and anteroposterior translation (mean, 0.1 mm) in association with a cruciate-retaining mobile-bearing total knee replacement. Spitzer et al. found that the use of a mobile-bearing total knee replacement did not reduce the need for lateral retinacular release as compared with that noted in their series of fixed-bearing total knee replacements. Pagnano et al., in a prospective, randomized study, found that the rotating-platform total knee replacement did not decrease the need for lateral retinacular release or the prevalence of patellar tilt or subluxation and did not increase knee flexion or stair-climbing ability. Thornhill et al. compared 100 fixed-bearing total knee replacements with 113 rotating-platform total knee replacements and found no significant difference in the mean range of motion at two years postoperatively. Ridgeway and Moskal reviewed twenty-five cases of early instability following meniscal-bearing or rotating-platform total knee replacement and concluded that any potential long-term benefit of design innovations must be balanced with known problems leading to early failure. Sansone et al. reviewed the five to nine-year results of their first 110 rotating-platform total knee replacements. The authors reported four revisions (two because of instability, one because of loosening, and one because of tibial insert dislocation) and a 93.7% survival rate with revision for any reason as the end point. Woolson and Northrop compared fifty-seven rotating-platform total knee replacements with forty-five fixed-bearing total knee replacements and found no difference in knee scores, range of motion, or radiographic findings after a mean duration of follow-up of forty-one months. However, three mobile-bearing knees required early revision because of the failure of rotating patellar or tibial polyethylene implants. Ranawat et al. compared the fixed-bearing PFC Sigma total knee replacement (DePuy, Warsaw, Indiana) with the rotating-platform version of the same design in a study of twenty-six patients and found no revisions and no significant differences in any measured parameter after short-term follow-up. Barrack et al., in a report on a consecutive series of eighty-two cementless mobile-bearing total knee replacements in knees with mild or moderate deformity, found an 8% rate of revision for the treatment of failure of tibial ingrowth, a lower Knee Society score (161 compared with 184, p < 0.05), a higher prevalence of pain that was rated as more than mild (23% compared with 7%, p < 0.01), and a trend toward a smaller arc of motion (106° compared with 115°, p < 0.2) when the study group was compared with a group of historical controls after a minimum duration of follow-up of two years. Aigner et al. performed a prospective, randomized, double-blind study of fifty total knee arthroplasties that were performed with use of the LCS-Universal prosthesis (DePuy). The patients were randomized to receive a deep-dish rotating platform or a mobile bearing that allowed anteroposterior translation (the latter of which requires an intact posterior cruciate ligament). After one year of follow-up, the authors reported that the latter design did not regularly restore femoral rollback and did not improve range of motion. Kim and Kim performed a study of 190 patients undergoing bilateral knee replacement who received an anteroposterior glide LCS total knee replacement (DePuy) on one side and a rotating-platform LCS total knee replacement on the other side. The authors found no significant differences in clinical or radiographic results after a minimum duration of follow-up of five years.
While a uniform definition of less or minimally invasive surgery remains evasive, many reports were presented or published on this topic and on the role of computer assistance in the operating room. Koyonos et al., using an image-free navigation system with manual instruments, found that alignment errors most commonly occur during manual pinning of the tibial and femoral cutting blocks. Mondanelli et al. studied fifty total knee arthroplasties that were performed through a minimally invasive subvastus approach without eversion of the patella and compared the results with those in a matched control group. The duration of the procedure was ten minutes longer and the amount of blood loss was 150 mL less in the minimally invasive surgery group. The minimally invasive surgery group had less pain, more rapid achievement of 90° of flexion, and a shorter time to performing a straight leg raise. However, the minimally invasive surgery group had more complications (including one patellar tendon injury and one lateral femoral condyle fracture) and more radiographic outliers (two varus tibiae). Similarly, Dalury compared two groups of thirty knees that were treated either with minimally invasive surgery or with a standard approach. While the knees in the minimally invasive surgery group had more rapid progression of range of motion and required the use of less pain medication, they were associated with a longer surgical time, increased minor wound-healing complications, and more frequent tibial component malalignment (observed in four of thirty knees). Scuderi et al. reported on 100 consecutive primary total knee arthroplasties (excluding those in knees with deformity, <90° of flexion, or previous incisions) that were performed through incisions of <5.5 in (<14.0 cm) and found a lower drop in the hemoglobin level (3.1 compared with 4.2 g/dL) and slightly shorter length of stay (3.9 compared with 4.4 days) in the mini-incision group and reported no differences between the two groups with regard to postoperative alignment, motion, walking ability, or pain scores. Bonutti et al. reviewed the minimum two-year results of 219 minimally invasive total knee arthroplasties and reported a 98% rate of good and excellent Knee Society scores, six manipulations, and five reoperations (including two revisions for the treatment of infection, two tibial revisions for the treatment of pain, and one revision for the treatment of posterior cruciate ligament rupture). Laskin et al. evaluated the use of a mini-midvastus approach without patellar eversion in a study of fifty-one patients and found that these patients had a shorter time to straight leg raising, used less epidural analgesia, had a more rapid progression of flexion, and were discharged 18% faster compared with patients who had been managed with a standard incision. Hungerford, in a symposium at the open meeting of the Knee Society, discussed the opposing view that there is no proven meaningful benefit of minimally invasive surgery techniques and that the reduced exposure will only make appropriate alignment more difficult to obtain, especially for the occasional knee surgeon, with a resultant increase in technical errors. Several investigators reviewed the value of computer assistance in total knee arthroplasty. Victor performed a prospective, randomized, controlled trial to evaluate the use of image-based computer-assisted surgery in total knee arthroplasty and reported significant differences in operative time (p < 0.005) but found no differences in blood loss, patellar alignment, tibial slope, or postoperative scores. However, he found significant improvement in coronal alignment, with neutral mechanical alignment being achieved in all knees that were treated with the computer-assisted procedure (p < 0.0001). Bolognesi and Hofmann described a study in which fifty total knee arthroplasties that were performed with an imageless computer-assisted-surgery system were compared with fifty total knee arthroplasties that were performed with standard instruments. The authors found that 98% of the femoral components and 100% of the tibial components were aligned within 3° of the goal position in the computer-assisted-surgery group, compared with 90% of the femoral components and 92% of the tibial components in the standard group. Kim and Wixson performed a similar comparison and found that 58% of the components were within 2° of neutral alignment in the manual group, compared with 78% of those in the computer-assisted-surgery group (p = 0.008).
Rotational alignment of the femoral component was the topic of several reports. Vaidya et al. found that the method of performing the posterior condylar cut parallel to a previously performed tibial cut was more reliable (as determined with postoperative computed tomography scanning) and was associated with better functional scores compared with the method of using the often ill-defined epicondylar axis. Stulberg et al. used computer assistance with preoperative and postoperative computed tomography scans and found that the mean relationship between the posterior condylar axis and the epicondylar axis was 4.69° of internal rotation. Similarly, the mean relationship of Whiteside's line to the epicondylar line was 0.07°. The authors found that the intraoperative determination of the posterior condylar axis and the epicondylar axis using surface registration techniques was unreliable, suggesting that the use of Whiteside's line was more reliable. Blaha used a cadaveric model to calculate the average flexion-extension axis for five specimens and found that this "functional plane" passed just lateral to the anterior-inferior iliac spine to the center of the distal part of the femur, through the tibial tubercle and the neck of the talus. On the basis of this information, he concluded that, in clinical practice, a "functional alignment" that is achieved by cutting the distal part of the femur in 3° of valgus (in contrast to the usual 6°) would aid in reestablishing the normal plane of flexion and extension. Sodha et al., evaluated the need for lateral retinacular release as a function of femoral component rotation and found that the need for release significantly decreased (p < 0.0001) when the method of using the epicondylar axis as a guide to rotational alignment was compared with the method of performing equal posterior condylar resections. Hanada et al., in a study of twelve cadaveric knees, compared the alignment and stability characteristics of six knees that were aligned and resected with use of a tensioned gap technique with those of six knees that were treated with a measured resection technique. In the group treated with the tensioned gap technique, all six knees shifted toward varus in flexion and the patellar groove shifted laterally relative to the neutral position. In the group treated with the measured resection technique, all six knees had near normal varus-valgus and rotational stability tests, alignment, patellar groove positioning, and load-transfer characteristics. Incavo et al. compared these two resection techniques in a study of fifty total knee arthroplasties and found that the flexion space-balancing technique led to a smaller size selection in 56% of knees (p < 0.05) when compared with the measured resection technique, especially in varus knees. The authors indicated that a tight flexion space could lead to inferior clinical outcomes.
Soft-tissue balancing was the topic of several reports. Politi and Scott
reported on a technique of cruciform lateral release in a study of thirty-five
consecutive knees with The debate regarding the complication rates associated with simultaneous bilateral total knee arthroplasty and unilateral total knee arthroplasty was the topic of three reports. Sporer et al. compared 514 unilateral total knee arthroplasties with 510 simultaneous bilateral total knee arthroplasties and found increases in the amount of blood loss, the need for transfusion, the duration of hospital stay, the occurrence of myocardial infarction, the frequency of postoperative confusion, and the need for intensive monitoring in the bilateral group. However, the thirty-day and one-year rates of mortality, infection, and pulmonary embolism were the same. In a debate at the interim meeting of the Knee Society, Ritter reported on 4100 simultaneous bilateral total knee arthroplasties and noted excellent clinical results. He reported that simultaneous bilateral total knee arthroplasty may pose a greater risk of death in the early postoperative course, generally in relation to the older age of the patient at the time of surgery. In the same debate, Hanssen argued that the available literature regarding the safety and efficacy of simultaneous bilateral total knee arthroplasty has notable selection bias and that the safety of this procedure therefore has not been established.
The most appropriate form of prophylaxis against thromboembolic disease following total knee arthroplasty remains controversial. The Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy was described in Chest14. This evidence-based review of thromboprophylaxis gave Grade-1A recommendations to low-molecular-weight heparin, fondaparinux, or adjusted-dose vitamin K antagonist (warfarin, with a target international normalized ratio of 2.0 to 3.0) for patients undergoing elective total hip or knee arthroplasty. The recommended duration of treatment is at least ten days. Colwell et al. reported on a multicenter clinical trial comparing fixed-dose ximelagatran (Exanta) with warfarin (target international normalized ratio, 2.5) and found that the efficacy of oral ximelagatran (36 mg twice daily) was superior to that of warfarin for prophylaxis against total venous thrombotic events (p = 0.003). Ximelagatran is administered orally and requires no coagulation monitoring, which would greatly simplify such prophylaxis.
Several authors reported on the results of total knee arthroplasty in patients with deformities or stiffness. Elkus et al. reported on forty-two total knee arthroplasties (in thirty-five patients) that were performed with use of an inside-out soft-tissue release of the posterolateral capsule and pie-crusting of the iliotibial band for the treatment of knees with a preoperative valgus deformity of >10°. After a minimum duration of follow-up of five years, the mean Knee Society score was 93, three knees had been revised (because of infection, polyethylene exchange, and patellar loosening in one knee each), and no knee had late instability. Lachiewicz, in a study of forty-two primary constrained total knee arthroplasties that were performed for the treatment of severe valgus deformity (twenty-seven knees), severe flexion contracture (twelve knees), and other reasons (three knees), reported that the ten-year survival rate was 96% (95% confidence interval, 90.6% to 100%) with component revision for loosening as the end point. Ritter et al., in a study of eighty-two primary cruciate-retaining total knee arthroplasties in seventy-five patients with preoperative varus or valgus deformities of least 20°, reported no significant difference in knee scores, alignment, or revision rates when the study group was compared with a matched control group. Sheth et al., in a study of fourteen total knee arthroplasties in nine patients with hemophilic arthropathy, reported significant improvement in Knee Society scores with nine complications in six knees after a mean duration of follow-up of seventy-seven months. Bae et al., in a study of thirty-two total knee arthroplasties in patients with complete or partially ankylosed knees, reported a mean Knee Society score of 86 points and a 12.5% prevalence of complications (two infections, one fracture, and one peroneal nerve palsy) after a mean duration of follow-up of ten years. There were several reports on total knee arthroplasty in obese patients. Namba et al. prospectively compared the results of primary total knee arthroplasty in a group of obese patients (body-mass index, >35) with those in a group of nonobese patients (body-mass index, <35) and found a higher rate of infection in the obese group (odds ratio, 6.7). Foran et al. performed a similar comparison of the results of primary total knee arthroplasty in a study of twenty-seven obese patients and thirty nonobese patients and reported that the nonobese group had higher knee scores and a lower rate of revisions (three compared with nine) after a mean duration of follow-up of fifteen years. The same group of authors performed another study in which sixty-eight obese patients (seventy-eight total knee arthroplasties) were clinically and radiographically compared with a matched control group of nonobese patients. The obese group was found to have a significantly lower percentage of Knee Society scores of >80 points (88% compared with 99%) and a significantly higher rate of revision than the nonobese group (p = 0.02). Several reports discussed the effect of certain preoperative diagnoses on clinical outcomes. Saleh et al. compared the clinical results of twenty-three primary total knee arthroplasties in patients who were receiving Workers' Compensation with those of twenty-one primary total knee arthroplasties in an age-matched control group after a mean duration of follow-up of fifty-six months. The authors reported significantly higher Knee Society scores in the control group and noted that only five of the twenty-one patients in the Workers' Compensation group returned to their previous occupation. Rose et al., in a study of twelve total knee arthroplasties in ten patients with Ehlers-Danlos syndrome, reported a mean Knee Society score of 70 points after a mean duration of follow-up of sixty-five months and concluded that total knee arthroplasty appears to be an effective option for the treatment of knee arthritis and instability in these patients. Shih et al. compared the results of sixty total knee arthroplasties in a group of fifty-one patients who had cirrhosis with those in a matched control group and found significantly more blood loss, a longer hospital stay, more complications (including a 21% rate of infection), and a higher mortality rate in the cirrhosis group (p < 0.006 for all comparisons). Parvizi et al. reviewed 166 condylar total knee arthroplasties that had been performed with cement in 118 patients who had had a previous proximal tibial osteotomy and reported significant improvements in Knee Society scores and range of motion after a mean duration of follow-up of fifteen years. Thirteen revisions (prevalence, 8%) were performed at a mean of 5.9 years, and progressive complete radiolucent lines were observed around seventeen tibial components and seven femoral components.
Controversy continues with regard to patellar resurfacing during primary total knee arthroplasty. Burnett et al., in a randomized trial of patellar resurfacing, found a 15% rate of revision in the nonresurfaced group (with three of seven revisions performed for patellar resurfacing) and a 5% rate of revision in the resurfaced group (with one revision performed for the treatment of a patellar fracture) at a minimum of ten years. No significant difference was found with regard to Knee Society scores, Western Ontario McMaster instrument (WOMAC) scores, Short Form-12 (SF-12) scores, anterior knee pain, or radiographic outcomes. Khatod et al. reviewed twenty-eight knees that had undergone primary total knee arthroplasty without patellar resurfacing and subsequently had undergone resurfacing because of anterior knee pain. The authors reported that, after an average duration of follow-up of 2.9 years, the Knee Society scores for the study group were inferior to those for historical controls. There has been some renewed interest in isolated patellofemoral resurfacing for the treatment of symptoms limited to the patellofemoral joint. Argenson et al. reviewed fifty-seven isolated patellofemoral arthroplasties and reported that fourteen revisions had been performed because of tibiofemoral arthritic progression, eleven had been performed because of femoral loosening, and four had been performed because of stiffness, giving a 58% survival rate at sixteen years. Merchant studied fifteen patients who had undergone patellofemoral arthroplasty and reported a 93% rate of good or excellent results after a mean duration of follow-up of 3.75 years. Rand et al. studied nine patients who had undergone patellectomy for the treatment of a patellar fracture following total knee arthroplasty and reported a mean Knee Society score of 81 points, a mild extensor lag in four patients, and two major complications (tendon rupture and extensor mechanism instability).
Many reports dealt with the prevalence and treatment of complications following total knee replacement. Katz et al. analyzed claims data for Medicare patients who had had an elective primary total knee replacement and found that patients who had been managed at hospitals and by surgeons with greater volumes of total knee replacements had a lower risk of perioperative adverse events15. Dalury and Jiranek reviewed 500 consecutive primary total knee arthroplasties and found that 15% were associated with the development of heterotopic ossification. Heterotopic ossification was more common in heavier patients and in men. In only four patients did the heterotopic ossification appear to influence the outcome. Bezwada et al. reviewed thirty periprosthetic supracondylar fractures that had been treated with retrograde nailing (eighteen) or traditional plate fixation (twelve) and concluded that retrograde nailing was the treatment of choice when possible; however, both techniques yielded satisfactory results. Stiffness following total knee replacement remains a difficult problem to treat. Haidukewych et al., in a study of sixteen knees that had undergone formal revision of well-fixed components because of stiffness after primary total knee arthroplasty, reported that the rate of satisfaction was 73% and that the Knee Society pain score improved from 28 to 65. Maloney et al. reviewed twenty-three knees that had undergone a reoperation for the treatment of stiffness (including twelve knees that had undergone polyethylene exchange and soft-tissue releases, three that had undergone tibial component revision, and eight that had undergone revision of both components) and reported improvement in the mean arc of motion from 60.5° to 82.5°. Kim et al. reported a 1.3% prevalence of stiffness (defined as a >15° flexion contracture and/or <75° of flexion) after total knee arthroplasty and found that revision surgery was a satisfactory treatment option in this subgroup of patients, with 93% having a modestly improved arc of motion. Burnett et al., in a study on the treatment of extensor mechanism disruption following total knee arthroplasty, found that extensor mechanism allografting (involving the use of a tibial tubercle-patellar tendon-patella-quadriceps tendon graft) was successful when the graft was tensioned tightly in extension during implantation. Kollender et al. reported on the use of Gore-Tex strips and a gastrocnemius flap to augment a primary repair in seven patients, all of whom had a good to excellent functional outcome. Rand delivered an Instructional Course Lecture entitled "Extensor Mechanism Complications Following Total Knee Arthroplasty," which provided a very thorough review of many patellofemoral complications16.
Infection is one of the most dreaded complications of total knee replacement. Deirmengian et al. reported on a novel approach for the diagnosis of infection on the basis of neutrophil gene expression. The authors found a large number of genes (124) that were expressed at significantly higher levels (0.0000001 < p < 0.0001) in infection when compared with neutrophils responding to gout. This approach holds tremendous promise for aiding the clinician in the diagnosis of infection. Further investigations of this technique are underway. The treatment of infection at the site of a total knee replacement was the topic of several reports. Haleem et al. reported on ninety-four patients (ninety-six knees) who underwent a two-stage revision for the treatment of infection at a mean of 7.2 years of follow-up and found that fifteen knees (16%) had required reoperation for the treatment of reinfection (nine knees) or loosening (six knees). Yonekura et al. found that two-stage revision was successful for the treatment of 91% of infections that had occurred at the site of a primary total knee arthroplasty and 82% of infections that had occurred at the site of a revision total knee arthroplasty. The highest success rates were noted after the treatment of early postoperative and acute hematogenous infections. Patient age, gender, body-mass index, diagnosis, and comorbidity had no effect on success or failure. Durbhakula et al. used an articulating cement spacer in twenty-four two-stage revisions that were performed for the treatment of infection and reported a 92% success rate, with minimal soft-tissue contracture and bone loss. In a study by Meek et al., the functional results associated with the use of an articulating antibiotic spacer for two-stage revision in patients with infection were compared with the results of standard revision in patients without infection. The authors reported that the rate of recurrent infection was 4% and that the two groups had very similar clinical and functional results.
Wear and osteolysis remain a major concern following total knee arthroplasty. Conditt et al. studied 124 retrieved polyethylene tibial inserts of twelve different designs after implantation periods ranging from zero to 180 months and frequently found moderate to severe wear of the nonarticulating surface (backside) in association with all designs, independent of the capture mechanism, suggesting that design modifications are needed. Tomek et al. evaluated ninety-seven retrieved constrained tibial inserts and noted that burnishing, scratching, pitting, and deformation were uniformly present, although infection, loosening, and instability were the most common forms of failure. With regard to osteolysis, Miura et al. reported that the oblique posterior femoral condylar radiographic view was significantly better than a true lateral view for the detection of radiolucencies of the posterior femoral condyles (p < 0.0005)17. Reish et al. found that, when multiple-detector computed tomography was used as the standard, plain radiographs detected only 20% of osteolytic lesions around twenty-six total knee arthroplasties. Collier et al. investigated the factors of backside interface and polyethylene sterilization method in a study of 365 cruciate-retaining total knee replacements (Anatomic Modular Knee; DePuy) with at least five years of follow-up. The authors found that staggered shifts toward a polished baseplate and away from gamma-irradiated-in-air polyethylene dramatically reduced the prevalence of osteolysis associated with this design, from 24% to 2%. Lachiewicz and Soileau reviewed the results of 193 total knee arthroplasties that had been performed in 131 patients with use of the modular Insall-Burstein II posterior stabilized prosthesis (Zimmer, Warsaw, Indiana) and reported no instances of tibial loosening, eight tibial osteolytic lesions, a 16% prevalence of nonprogressive radiolucent lines, and three reoperations after a mean duration of follow-up of seven years. Fehring et al. reported on 1287 primary total knee arthroplasties after a minimum duration of follow-up of five years. Radiographic analysis was performed by an independent radiologist. The prevalence of wear-related failure was 8.4%, and the thirteen-year survival rate was 82.6%. Five variables were found to be significantly correlated with wear-related failure: patient age, gender, polyethylene sheet vender, polyethylene finishing method, and polyethylene shelf age.
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Introduction
Treatment of Osteoarthritis...
15° of
valgus