Showing papers in "Clinical Orthopaedics and Related Research in 2007"

How to write a systematic review

Abstract: Evidence-based medicine (EBM) is the combination of the best available research evidence with clinical experience and patient needs. The concept of EBM as a part of clinical decision making has become increasingly popular over the last decade. In the hierarchy of studies meta-analysis and systematic reviews occupy the highest levels. A systematic review of a clinical question can be performed by following a relatively standard form. These techniques as described here can be performed without formal training. Systematic reviews conducted in this fashion can be used as a higher form of current concepts or as review articles and replace the traditional expert opinion narrative review.

Anatomy of the anterior cruciate ligament with regard to its two bundles.

Abstract: The anterior cruciate ligament (ACL) consists of two major fiber bundles, namely the anteromedial and posterolateral bundle. When the knee is extended, the posterolateral bundle (PL) is tight and the anteromedial (AM) bundle is moderately lax. As the knee is flexed, the femoral attachment of the ACL becomes a more horizontal orientation; causing the AM bundle to tighten and the PL bundle to relax. There is some degree of variability for the femoral origin of the anterome-dial and posterolateral bundle. The anteromedial bundle is located proximal and anterior in the femoral ACL origin (high and deep in the notch when the knee is flexed at 90 degrees ); the posterolateral bundle starts in the distal and posterior aspect of the femoral ACL origin (shallow and low when the knee is flexed at 90 degrees ). In the frontal plane the anteromedial bundle origin is in the 10:30 clock position and the postero-lateral bundle origin in the 9:30 clock position. At the tibial insertion the ACL fans out to form the foot region. The anteromedial bundle insertion is in the anterior part of the tibial ACL footprint, the posterolateral bundle in the posterior part. While the anteromedial bundle is the primary restraint against anterior tibial translation, the posterolateral bundle tends to stabilize the knee near full extension, particularly against rotatory loads.

First-time traumatic patellar dislocation: a systematic review.

Abstract: Acute patellar dislocations can result in patellar instability, pain, recurrent dislocations, decreased level of sporting activity, and patellofemoral arthritis The initial management of a first-time traumatic patellar dislocation is controversial with no evidence-based consensus to guide decision making Most first-time traumatic patellar dislocations have been traditionally treated nonoperatively; however, there has been a recent trend in initial surgical management We performed a systematic review of Level I-IV studies to make evidence-based medicine recommendations on how a clinician should approach the diagnosis and treatment of a first-time traumatic dislocation More specifically we answer the primary question of when initial treatment should consist of operative versus closed management Based on the review of 70 articles looking at study design, mean followup, subjective and validated outcome measures, redislocation rates, and long-term symptoms, we recommend initial nonoperative management of a first-time traumatic dislocation except in several specific circumstances These include the presence of an osteochondral fracture, substantial disruption of the medial patellar stabilizers, a laterally subluxated patella with normal alignment of the contralateral knee, or a second dislocation, or in patients not improving with appropriate rehabilitation

Osteosarcoma, Chondrosarcoma, and Ewing's Sarcoma: National Cancer Data Base Report

Abstract: We summarize descriptive epidemiologic and survival data from the National Cancer Data Base of the American College of Surgeons for 26,437 cases of osteosarcoma (n = 11,961), chondrosarcoma (n = 9606), and Ewing's sarcoma (n = 4870) from 1985 to 2003. Survival data are reported on cases with a minimum 5-year followup from 1985 to 1998 (8,104 osteosarcomas, 6,476 chondrosarcomas, and 3,225 Ewing's sarcomas). The relative 5-year survival rate was 53.9% for osteosarcoma, 75.2% for chondrosarcoma, and 50.6% for Ewing's sarcoma. Survival rates did not change notably over the collection period. Within osteosarcomas, the relative 5-year survival rates were 52.6% for high grade, 85.9% for parosteal, and 17.8% for Paget's subtypes. For osteosarcoma patients, the relative 5-year survival rate was 60% for those younger than 30 years, 50% for those aged 30 to 49 years, and 30% for those aged 50 years or older. Within chondrosarcomas, the relative 5-year survival rate was 76% for conventional, 71% for myxoid, 87% for juxtacortical, and 52% for mesenchymal. While the National Cancer Data Base has limitations, the survival data and demographics for bone sarcomas are unprecedented in numbers and duration. Our report supports continued efforts to refine data collection and stimulate further data analysis.

Double-bundle ACL reconstruction can improve rotational stability.

Abstract: Double-bundle anterior cruciate ligament (ACL) reconstruction reproduces anteromedial and posterolateral bundles, and thus has theoretical advantages over conventional single-bundle reconstruction in controlling rotational torque in vitro. However, its superiority in clinical practice has not been proven. We analyzed rotational stability with three reconstruction techniques in 60 consecutive patients who were randomly divided into three groups (double-bundle, anteromedial single-bundle, posterolateral single-bundle). In the reconstructive procedure, the hamstring tendon was harvested and used as a free tendon graft. Followup examinations were performed 1 year after surgery. Anteroposterior laxity of the knee was examined with a KT-1000 arthrometer, whereas rotatory instability, as elicited by the pivot shift test, was assessed using a new measurement system incorporating three-dimensional electromagnetic sensors. Routine clinical evaluations, including KT examination, demonstrated no differences among the three groups. However, using the new measurement system, patients with double-bundle ACL reconstruction showed better pivot shift control of complex instability than patients with anteromedial and posterolateral single-bundle reconstruction.

The Cellular and Molecular Biology of Periprosthetic Osteolysis

Abstract: The generation of prosthetic implant wear after total joint arthroplasty is recognized as the major initiating event in development of periprosthetic osteolysis and aseptic loosening, the leading complication of this otherwise successful surgical procedure. We review current concepts of how wear debris causes osteolysis, and report ideas for prevention and treatment. Wear debris primarily targets macrophages and osteoclast precursor cells, although osteoblasts, fibroblasts, and lymphocytes also may be involved. Molecular responses include activation of MAP kinase pathways, transcription factors (including NFkappaB), and suppressors of cytokine signaling. This results in up-regulation of proinflammatory signaling and inhibition of the protective actions of antiosteoclastogenic cytokines such as interferon gamma. Strategies to reduce osteolysis by choosing bearing surface materials with reduced wear properties should be balanced by awareness that reducing particle size may increase biologic activity. There are no approved treatments for osteolysis despite the promise of therapeutic agents against proinflammatory mediators (such as tumor necrosis factor) and osteoclasts (bisphosphonates and molecules blocking receptor activator of NFkappaB ligand [RANKL] signaling) shown in animal models. Considerable efforts are underway to develop such therapies, to identify novel targets for therapeutic intervention, and to develop effective outcome measures.

The 2007 Frank Stinchfield Award. The biomechanics of the hip labrum and the stability of the hip.

Abstract: We explored the mechanical factors leading to the formation of labral tears and the effect of these lesions on hip kinematics at the extremes of joint motion. Using a 3D motion analysis system, the stability of six cadaveric hips was measured during loading maneuvers known to impose anterior loads on the joint margin. These measurements were repeated following venting of the capsule, and after creation of a 15-mm tear in the intact labrum. Compared to the intact hip, 43% and 60% less force was required to distract the femur by 3 mm after venting and creation of a tear. An ER torque of 177 in-lbf in 30 degrees of flexion caused the vented and torn specimens to rotate 1.5 degrees +/- 2.7 degrees and 7.1 degrees +/- 4.7 degrees more than the intact specimen, and the femoral head to displace 1.21 +/- 0.53 mm and 0.67 +/- 0.35 mm, respectively. A breach of the integrity of labral function is shown to lead to decreased femoral stability relative to the acetabulum during extreme ranges of motion.

Indications for rotator cuff repair: a systematic review.

Abstract: Despite the popularity of surgical repair of rotator cuff tears, literature regarding the indications for and timing of surgery are sparse. We performed a systematic review of the literature to investigate factors influencing the decision to surgically repair symptomatic, full-thickness rotator cuff tears. Specifically, how do demographic variables, duration of symptoms, timing of surgery, physical examination findings, and size of tear affect treatment outcome and indications for surgery? We reviewed the best available evidence, which offers some guidelines for surgical decision making. Variables suggest earlier surgical intervention may be needed in the setting of weakness and substantial functional disability. With regard to demographic variables, the evidence is unclear regarding their association with treatment outcome. However, older chronological age does not seem to portend a worse outcome. Pending worker's compensation claims does seem to negatively affect treatment results. Further research is required to define the indications for surgery for full thickness rotator cuff tears. However, the design and conduct of an ethical study to obtain Level I evidence on this issue will be a major challenge.

Dynamic function of the ACL-reconstructed knee during running.

Abstract: Little is known about the three-dimensional behavior of the anterior cruciate ligament (ACL) reconstructed knee during dynamic, functional loading, or how dynamic knee function changes over time in the reconstructed knee. We hypothesized dynamic, in vivo function of the ACL-reconstructed knee is different from the contralateral, uninjured knee and changes over time. We measured knee kinematics for 16 subjects during downhill running 5 and 12 months after ACL reconstruction (bone-patellar tendon-bone or quadrupled hamstring tendon with interference screw fixation) using a 250 frame per second stereoradiographic system. We used repeated-measures ANOVA to ascertain whether there were differences between the uninjured and reconstructed limbs and over time. We found no differences in anterior tibial translation between limbs, but reconstructed knees were more externally rotated and in more adduction (varus) during the stance phase of running. Anterior tibial translation increased from 5 to 12 months after surgery in the reconstructed knees. Anterior cruciate ligament reconstruction failed to restore normal rotational knee kinematics during dynamic, functional loading and some degradation of graft function occurred over time. These abnormal motions may contribute to long-term joint degeneration associated with ACL injury and reconstruction.

The biology of aseptic osteolysis.

Abstract: Total hip arthroplasty is one of the most commonly performed and successful elective orthopaedic procedures. However, numerous failure mechanisms limit the long-term success including aseptic osteolysis, aseptic loosening, infection, and implant instability. Aseptic osteolysis and subsequent implant failure occur because of a chronic inflammatory response to implant-derived wear particles. To reduce particulate debris and their consequences, implants have had numerous design modifications including high-molecular-weight polyethylene sockets and noncemented implants that rely on bone ingrowth for fixation. Surgical techniques have improved cementation with the use of medullary plugs, cement guns, lavage of the canal, pressurization, centralization of the stem, and reduction in cement porosity. Despite these advances, aseptic osteolysis continues to limit implant longevity. Numerous proinflammatory cytokines, such as interleukin-1, interleukin-6, tumor necrosis factor-alpha, and prostaglandin E2, have proosteoclastogenic effects in response to implant-derived wear particles. However, none of these cytokines represents a final common pathway for the process of particle-induced osteoclast differentiation and maturation. Recent work has identified the fundamental role of the RANKL-RANK-NF-kappaB pathway not only in osteoclastogenesis but also in the development and function the immune system. Thus, the immune system and skeletal homeostasis may be linked in the process of osteoclastogenesis and osteolysis.

Evidence based medicine: what it is and what it isn't. 1996.

Abstract: After training in internal medicine, nephrology and epidemiology, Dave Sackett's first career (age 32) was as the founding Chair of Clinical Epidemiology & Biostatistics at McMaster. In his second career he began to design, execute, interpret, monitor, write and teach about randomized clinical trials, an activity that continues to the present, some 200 trials later. His third career was dedicated to developing and disseminating \"critical appraisal\" strategies for busy clinicians, and ended when he decided he was out of date clinically and returned (at age 49) to a two-year \"retreading\" residency in General Internal Medicine. His fourth career (and the only one he didn't enjoy) was as Physician-in-Chief at Chedoke-McMaster Hospitals. His fifth career was as Head of the Division of General Internal Medicine for Hamilton and Attending Physician at the Henderson General Hospital. When a chair was created for him at Oxford, he took up his sixth career as foundation Director of the NHS R&D Centre for Evidence-Based Medicine, Consultant on the Medical Service at the John Radcliffe Hospital, and Foundation Co-Editor of Evidence-Based Medicine. At present he is Director of the Trout Research & Education Centre at Irish Lake in Canada, where he reads, researches, writes and teaches about clinical-practice research.

On the injuries to the ligaments of the knee joint: a clinical study. 1938.

Abstract: Ivar Palmer was born in 1897 in western Sweden. Soon afterward, his family moved to the province of Jämtland, in northern Sweden. His father was a minister. Ivar Palmer graduated from high school in 1915 and received his M.D. degree in Stockholm in 1923. He completed his residency in Stockholm at the Serafimer Hospital, which was then part of the Karolinska Institute. He served in northern Sweden until 1928. He then became chief of the Military Hospital at Karlsborg, in central Sweden. During the period from 1934 to 1939, he served as a senior staff member at the surgical department of the Sabbatsberg Hospital in Stockholm and wrote his famous thesis about knee ligament injuries, published in 1938. Having successfully defended his thesis, in 1939 he was appointed chief of a special section consisting of wards for trauma and military surgery in the newly opened Karolinska Hospital. He worked there from 1939 to 1942 and describes this in his autobiography as the most satisfactory period of his professional life. He was allowed to work as a “traumatologist.” In 1942 he became chief of surgery at the Sabbatsberg Hospital, and in 1947 was appointed chief of the Department of Surgery in the newly built Southern Hospital of Stockholm. He stayed there until he retired in 1962.

Pain and depression influence outcome 5 years after knee replacement surgery.

Abstract: UNLABELLED We previously reported preoperative depression, anxiety, and pain were associated with greater pain, more utilization of healthcare resources, and worse outcome 1 year after total knee arthroplasty. We asked whether these outcomes persisted over time and whether patients with unexplained heightened pain early after surgery were ultimately satisfied. We prospectively followed and evaluated 83 patients (109 TKAs) 5 years postoperative. The mean age was 66 years; 55% were women. Preoperative pain and depression predicted lower Knee Society score mostly related to lower function subscores. Although anxiety was associated with greater pain, worse function, and more use of resources in the first year after surgery, anxiety did not affect ultimate outcome. Most patients required a full year to recover from surgery but with negligible improvements in most parameters afterward. However, patients with heightened, unexplained pain at 1 year had progressive improvement in pain over several years. By 5 years, nearly all of these patients were satisfied. Therefore, assuming good range of motion and well-aligned implants, most patients with pain 1 year after surgery can be reassured pain ultimately improves. Depression drives long-term outcomes; the Knee Society score is influenced by psychologic variables and does not solely reflect issues related to the knee. Expansion of this tool to include measures sensitive to psychologic and other health factors should be considered. LEVEL OF EVIDENCE Level I, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The john insall award

Abstract: We previously reported preoperative depression, anxiety, and pain were associated with greater pain, more utilization of healthcare resources, and worse outcome 1 year after total knee arthroplasty. We asked whether these outcomes persisted over time and whether patients with unexplained heightened pain early after surgery were ultimately satisfied. We prospectively followed and evaluated 83 patients (109 TKAs) 5 years postoperative. The mean age was 66 years; 55% were women. Preoperative pain and depression predicted lower Knee Society score mostly related to lower function subscores. Although anxiety was associated with greater pain, worse function, and more use of resources in the first year after surgery, anxiety did not affect ultimate outcome. Most patients required a full year to recover from surgery but with negligible improvements in most parameters afterward. However, patients with heightened, unexplained pain at 1 year had progressive improvement in pain over several years. By 5 years, nearly all of these patients were satisfied. Therefore, assuming good range of motion and well-aligned implants, most patients with pain 1 year after surgery can be reassured pain ultimately improves. Depression drives long-term outcomes; the Knee Society score is influenced by psychologic variables and does not solely reflect issues related to the knee. Expansion of this tool to include measures sensitive to psychologic and other health factors should be considered.Level of Evidence: Level I, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

ACL reconstruction: a meta-analysis of functional scores.

Abstract: From individual randomized studies, it is unclear whether patellar tendon grafts or hamstring tendon grafts yield the best functional results after ACL reconstruction. Therefore, we performed a meta-analysis to provide quantitative data to compare patellar with hamstring grafts after ACL reconstruction with regard to knee function. We searched computerized databases for randomized controlled trials reporting one of the following outcomes related to function: final overall International Knee Documentation Committee score and return to preinjury level of activity. Studies were abstracted independently by two reviewers. Random effect models were used to pool the data. Fourteen trials (1263 patients) met the inclusion criteria. We found no difference in final overall International Knee Documentation Committee score or in the number of patients returning to full activity after patellar and hamstring graft reconstruction. Relative risk was 0.90 for final overall International Knee Documentation Committee Class A and 0.94 for return to preinjury level of activity in favor of patellar grafts. Quantitative interaction tests on the effect of treatment based on study quality, randomization status, number of strands used, and length of followup were non significant. At last followup, only 41% and 33% of patients, respectively, had patellar and hamstring grafts reconstructed reported as normal based on the final overall International Knee Documentation Committee score.

The frog-leg lateral radiograph accurately visualized hip cam impingement abnormalities.

Abstract: Radiographic evaluation of the anterolateral femoral head-neck junction is essential in diagnosing cam femoroacetabular impingement. We hypothesized the frog-leg lateral radiograph can accurately assess femoral head-neck offset abnormalities associated with cam femoroacetabular impingement. We reviewed the radiographs of 61 hips treated for cam impingement and 24 asymptomatic control hips. To characterize the anatomy of the femoral head-neck junction, the femoral head sphericity, the alpha-angle of Notzli et al, and head-neck offset were measured on all radiographs. Asphericity of the femoral head was detected more frequently in hips with impingement on all radiographic views when compared with control hips. The average alpha-angle was greater in hips with impingement on all views, with the greatest difference between hips with impingement and control hips seen on the frog-leg lateral view (65 degrees for hips with impingement versus 47 degrees for control hips). The average head-neck offset was decreased in hips with impingement on all views. The greatest difference between groups was seen on the frog-leg lateral view (6.6 mm for hips with impingement versus 9.3 mm for control hips). The frog-leg lateral radiograph provides accurate visualization of the femoral head-neck offset in patients being evaluated for femoroacetabular impingement.

Higher risk of failure of methicillin-resistant Staphylococcus aureus prosthetic joint infections.

Abstract: We determined the effect of methicillin resistance on the outcome of patients with Staphylococcus aureus prosthetic joint infections. From January 1995 to December 2004, 33% of 137 episodes of prosthetic joint infections were the result of S. aureus (in monomicrobial or polymicrobial cultures). Thirty-three (24%) episodes among 31 patients were the result of methicillin-susceptible S. aureus and 12 (9%) episodes among 12 patients were the result of methicillin-resistant S. aureus. Overall treatment failure rate was 38%. Patients with methicillin-susceptible S. aureus or methicillin-resistant S. aureus prosthetic joint infections did not differ in age, gender, comorbidities, joint age, prior surgical procedures performed on the affected joint, number of postsurgical medical complications, or duration of intravenous antimicrobial therapy. Patients with methicillin-resistant S. aureus prosthetic joint infection had longer hospital durations (median, 15 versus 10 days). Methicillin-resistant S. aureus in periprosthetic tissue culture resulted in a higher risk of treatment failure (hazard ratio, 9.2; 95% confidence interval, 2.40-35.46) than methicillin-susceptible S. aureus when controlling for joint location (total knee arthroplasty versus total hip arthroplasty [hazard ratio, 5.8; 95% confidence interval, 1.52-22.19]) and removal of hardware (hazard ratio, 0.24; 95% confidence interval, 0.077-0.75). Efforts should be made to prevent methicillin-resistant S. aureus infections of joint arthroplasties and develop new treatment modalities.

Realignment surgery as alternative treatment of varus and valgus ankle osteoarthritis.

Abstract: In patients with asymmetric (varus or valgus) ankle osteoarthritis, realignment surgery is an alternative treatment to fusion or total ankle replacement in selected cases. To determine whether realignment surgery in asymmetric ankle osteoarthritis relieved pain and improved function, we clinically and radiographically followed 35 consecutive patients with posttraumatic ankle osteoarthritis treated with lower leg and hindfoot realignment surgery. We further questioned if outcome correlated with achieved alignment. The average patient age was 43 years (range, 26-68 years). We used a standardized clinical and radiographic protocol. Besides distal tibial osteotomies, additional bony and soft tissue procedures were performed in 32 patients (91%). At mean followup of 5 years (range, 3-10.5 years), pain decreased by an average of 4 points on a visual analog scale; range of ankle motion increased by an average of 5 degrees . Walking ability and the functional parts of the American Foot and Ankle Society score increased by an average of 10 and 21 points, respectively, and correlated with achieved reversal of tibiotalar tilt and the score of Takakura et al. Revision surgery was performed in 10 ankles (29%), of which three ankles (9%) were converted to total ankle replacement. We believe the data support realignment surgery for patients with asymmetric ankle osteoarthritis.

Orthopaedic procedure volume and patient outcomes: a systematic literature review.

Abstract: The association between greater hospital procedure volumes and improved patient outcomes has been well established with respect to a variety of procedures and treatments. However, this association in orthopaedics has not been summarized systematically. We reviewed existing literature on associations between hospital and surgeon procedure volume and patient outcomes in orthopaedic surgery. The patient outcomes examined were mortality, hip dislocation, infection, revision, complications, functional outcome, and satisfaction. Of the 26 articles reviewed, most examined outcomes after primary joint arthroplasties (predominantly hip arthroplasties) with a relatively limited number of studies examining revision arthroplasties, hip fractures, spine, or general orthopaedics. No studies evaluated any other subspecialties. We found an association between higher hospital volumes and lower rates of mortality and hip dislocation. We also found an association between higher surgeon volume and lower rates of hip dislocation. All other associations were negative or inconclusive. In addition, surgeon volume had a greater effect on patients than hospital volume for primary and revision joint arthroplasties, whereas hospital volume was more strongly related to outcome than surgeon volume for the other procedures examined. Our findings suggest the need for additional studies in the various subspecialties to establish more definitive conclusions.

Range of motion in anterior femoroacetabular impingement.

Abstract: The range of motion of normal hips and hips with femoroacetabular impingement relative to some specific anatomic reference landmarks is unknown We therefore described: (1) the range of motion pattern relative to landmarks; (2) the location of the impingement zones in normal and impinging hips; and (3) the influence of surgical debridement on the range of motion We used a previously developed and validated noninvasive 3-D CT-based method for kinematic hip analysis to compare the range of motion pattern, the location of impingement, and the effect of virtual surgical reconstruction in 28 hips with anterior femoroacetabular impingement and a control group of 33 normal hips Hips with femoroacetabular impingement had decreased flexion, internal rotation, and abduction Internal rotation decreased with increasing flexion and adduction The calculated impingement zones were localized in the anterosuperior quadrant of the acetabulum and were similar in the two groups and in impingement subgroups The average improvement of internal rotation was 54 degrees for pincer hips, 85 degrees for cam hips, and 157 degrees for mixed impingement This method helps the surgeon quantify the severity of impingement and choose the appropriate treatment option; it provides a basis for future image-guided surgical reconstruction in femoroacetabular impingement with less invasive techniques

Single-and double-incision double-bundle ACL reconstruction.

Abstract: Double-bundle anterior cruciate ligament (ACL) reconstruction is intended to replicate the anatomy and the function of the anteromedial and posterolateral bundles of the native ACL to improve patients' satisfaction and knee stability. We prospectively assigned 75 consecutive patients with an isolated ACL lesion to one of three sequential groups of 25 patients each. Group I received a single-bundle, single-incision transtibial ACL reconstruction. Groups II and III received a double-bundle reconstruction with a single-incision transtibial technique or a double-bundle, twoincision outside-in technique, respectively. We obtained subjective International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score evaluations and objective International Knee Documentation Committee scores and KT-1000 measurements preoperatively and at followup. All patients reached a minimum followup of 2 years. KT side-to-side difference in Groups I, II, and III were 2.4, 1.6 and 1.4 mm, respectively. Group III had fewer patients with a positive pivot shift than Group I. The double-bundle double-incision outside-in ACL reconstruction resulted in improved anteroposterior stability and less residual pivot shift than single-incision single-bundle technique.

Role of obesity on the risk for total hip or knee arthroplasty.

Abstract: We asked whether there was an association between obesity levels and subsequent THA or TKA using data from 54,406 THA and TKA patients entered into the Canadian Joint Replacement Registry We compared these patients with a sample of the Canadian population using the Canadian Community Health Survey of 2006 We analyzed information from the Canadian Joint Replacement Registry to quantify the relative risk for THA or TKA in Canada for specific body mass index categories In reference to the acceptable weight category of body mass index less than 25 kg/m 2 , the risk for TKA and THA was 320- and 192-fold higher, respectively, for overweight individuals (body mass index 25-299 kg/m 2 ); 853- (TKA) and 342-fold (THA) higher for those in the obese Class I (body mass index 30-349 kg/m 2 ) category; 1873- (TKA) and 524-fold (THA) higher for those identified in obese Class II (body mass index 35-399 kg/m 2 ); and 3273- (TKA) and 856-fold (THA) higher for people in obese Class III group (body mass index > 40 kg/m 2 ) Thus, our data support an association between obesity and subsequent THA and TKA

Using navigation to measure rotation kinematics during ACL reconstruction.

Abstract: Rotational kinematics of the knee is not fully restored after single-bundle anterior cruciate ligament (ACL) reconstruction. Cadaveric experiments using knee testing machines have suggested anatomical reconstruction replacing the anteromedial and posterolateral bundles could restore knee kinematics more effectively than single-bundle reconstruction. However, practical tools to objectively assess knee rotational laxities clinically have not been available. We used an optically based computer-assisted navigation system to measure the tibiofemoral motion kinematics in four fresh whole cadavers. Standard clinical knee laxity tests (anterior drawer, Lachman, and pivot shift) were performed and the kinematics described in terms of tibial axial rotation and anteroposterior translation. Data were obtained for intact knees after excision of the ACL and sequential reconstruction of the anteromedial and posterolateral bundles. In the ACL-deficient knee, the mean maximum tibial rotation during the pivot shift test was 27 degrees and mean maximum translation 11 mm. Reconstruction of the anteromedial bundle reduced the rotational component to 18 degrees and translation to 7 mm. Reconstruction of the posterolateral bundle reduced rotation to 14 degrees . This pilot study suggests computer assisted navigation could provide a practical method to objectively measure the pivot shift and may be used clinically to demonstrate differences in the control of tibiofemoral rotation kinematics afforded by single and two-bundle ACL reconstructions.

Computer-assisted navigation increases precision of component placement in total knee arthroplasty.

Abstract: To the Editor: We read with interest the article “Computer-assisted Navigation Increases Precision of Component Placement in Total Knee Arthroplasty” by Haaker et al in the April 2005 edition of Clinical Orthopaedics and Related Research. We appreciate the commendable effort made by the authors for reporting an elaborately conducted study. Comparisons of navigation-assisted total knee arthroplasty (TKA) and conventional TKA rarely mention all the angles of prosthesis implantation and limb alignment and then provide the statistical analysis for each angle. However, the authors used some angles that did not match the references mentioned; moreover, they commented on results as better for a navigation system without providing adequate references for the values that they considered normal or exact. In the Materials and Methods section, the authors stated the sagittal femoral component angle was the angle between the ventral cortex axis of the femur and a line drawn perpendicular to the distal part of the femoral component. There is disparity between the figure quoted for this angle and the text description. The angle shown in the figure is measured between the tangent to the ventral femoral cortex and tangent at the prosthesis. No perpendicular line to the distal part of the femoral component is drawn. Moreover, the three references mentioned in the text for this angle do not match with the description in the text or the figure. The first reference, an article by Ewald, reported the Knee Society roentgenographic evaluation system, used a sagittal femoral angle measured between a line perpendicular to the distal metal-cement interface of the femoral component and a line parallel to the femoral shaft axis rather than the lines used by the authors. The second reference, an article by Mahaluxmivala et al, also mentioned the Knee Society roentgenographic evaluation system. The third reference was a paper regarding mechanism of failure in TKA which does not mention a sagittal femoral component angle. While reporting the sagittal femoral alignment in the Results section, the authors used the term exact alignment for 90° sagittal femoral component angle. There is no report in the literature regarding the exact or ideal sagittal femoral component angle, as this angle varies with anatomic anterior bowing of the femoral shaft. Even if we measure this angle using the method described by the authors in the figure, the central femoral cortex axis is not likely to be a straight line perpendicular to the tangent at the distal prosthetic-bone interface. In the Results section, the authors mentioned that the coronal femoral component was better aligned in the navigation group compared with the conventional TKA group, even though the mean angle in both groups was within 1° of exact perpendicular and the 95% confidence interval also was within 1° of exact perpendicular. The angle measured by the authors is the femoral half of the mechanical axis as they measured it between a line drawn from the center of the hip to the center of the knee and tangent at the prosthesis. The mechanical axis within 3° valgus or varus is associated with a better outcome, however, there is no report in the literature about a better outcome with varus alignment compared with valgus alignment within 1° of perpendicular for the concerned angle. We understand that the difference between two groups can be significant, but there is no evidence to determine which group has better alignment, although from the wide range of angles in the conventional group it can be interpreted that outliers might be more frequent in this group. The other angles also are measured along lines different from those mentioned in the Knee Society roentgenographic evaluation system. However, these can be accepted as the authors’ personal method for measuring the angles because they did not mention that these angles were measured in accordance with the Knee Society roentgenographic evaluation system. Correspondence to: Dilbans Singh Pandher, MS, Visiting Scholar, Department of Orthopaedic Surgery, Konkuk University Hospital, 4-12 Hwayangdong, Kwangjin-gu, Seoul 143-729, South Korea. Phone: 09872020337; E-mail: dilbans@yahoo.com. CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Number 454, pp. 281–282 © 2006 Lippincott Williams & Wilkins

Incidence of fracture-healing complications after femoral neck fractures.

Abstract: What is the relationship between the age or gender of the patient and the incidence of fracture-healing complications after internal fixation of intracapsular fractures? We aimed to determine the association between the age of the patient and fracture nonunion and also to establish if the gender of the patient had any influence on the occurrence of fracture nonunion. We prospectively studied 1133 patients with intracapsular fractures of the femoral neck treated by internal fixation. The overall incidence of nonunion was 19.3%. Fracture nonunion was less common for undisplaced fractures than for displaced fractures (48 of 565 [8.5%] versus 171 of 568 [30.1%]) and in men than in women (35 of 271 [12.9%] versus 184 of 862 [21.3%]). The incidence of nonunion progressively increased with age from one of 17 (5.9%) in patients younger than 40 years to 84 of 337 (24.9%) in patients in their 70s. For patients in their 80s, the incidence of nonunion began to decrease, but if patients who died within 1 year after injury were excluded, the incidence continued to increase. Our study showed an increased risk for intracapsular hip fractures developing nonunion with older age and in females.

Antibiotics for local delivery systems cause skeletal cell toxicity in vitro.

Abstract: Antibiotic concentrations associated with antibiotic bone cements may cause skeletal cell toxicity and prevent fracture healing. We investigated toxicity effects of dose and treatment time after exposure to three antibiotics commonly used in orthopaedic local drug delivery systems. We hypothesized a threshold exists for toxicity of osteoblasts and chondrocytes after treatment with ciprofloxacin, vancomycin, or tobramycin. To test this hypothesis, we first determined whether treatment with antibiotics caused differences in cellular morphology. Cells exposed to ciprofloxacin showed considerable changes in spread, cell membrane, and extensions. We next asked what dosage of antibiotic would cause reductions in osteoblast and chondrocyte cell numbers. Ciprofloxacin at a dose greater than 100 microg/mL and vancomycin and tobramycin at doses greater than 2000 microg/mL severely decreased cellular proliferation. Finally, we questioned whether observed decreases in cell numbers were the result of increased cellular toxicity or senescence. Released lactate dehydrogenase ratios were severely increased in osteoblasts. These data suggest the balance between the targeted microbicidal effects and host cellular toxicity is critical for skeletal cell survival and function.

Difference between the epicondylar and cylindrical axis of the knee.

Abstract: Locating the true flexion-extension axis of the knee can play an important role in component placement in a total knee arthroplasty, especially using contemporary computer-assisted surgical navigation. We determined if the commonly used transepicondylar axis is an accurate and reproducible substitute for the flexion-extension axis. Twenty-three fresh-frozen cadaveric distal femurs with intact soft tissue were imaged with computed tomography and reconstructed in three-dimensional virtual space. The transepicondylar axis was compared with a line equidistant from the articular surface of each femoral condyle. Measures were performed by three observers three times for each specimen. Interobserver and intraobserver variations were small, but the differences between axes were approximately 5 degrees. The difference between axes decreased when projected from three-dimensional space to traditional two-dimensional planes (coronal and transverse), explaining why this discrepancy has not been previously documented. The greater difference in three-dimensional space may account for midrange instability reported in total knee arthroplasty. The increased accuracy afforded by computer-assisted surgical navigation in total knee arthroplasty may be lost and increased malposition of components may occur if this discrepancy between reference axes is not appreciated and addressed.

Tibial Rotation is Not Restored after ACL Reconstruction with a Hamstring Graft

Abstract: Recent research suggests ACL reconstruction does not restore tibial rotation to normal levels during high demand activities when a bone-patellar tendon-bone graft is used. We asked if an alternative graft, the semitendinosus-gracilis (ST/G) tendon graft, could restore tibial rotation during a high demand activity. Owing to its anatomic similarity with the normal ACL we hypothesized the ST/G graft could restore excessive tibial rotation to normal healthy levels along with a successful reinstatement of the clinical stability of the knee. We assessed tibial rotation in vivo, using gait analysis. We compared the knees of ACL reconstructed patients with an ST/G graft to their intact contralateral and healthy controls during a pivoting task that followed a stair descent. We also evaluated knee stability after ACL reconstruction with standard clinical tests. ACL reconstruction with the ST/G graft and with current techniques did not restore tibial rotation to previous physiological levels during an activity with increased rotational loading at the knee, although abnormal anteroposterior (AP) tibial translation was restored.

Tuberculosis of the spine: a review.

Abstract: We analyzed 124 papers published in the English language literature to define the indications and timing of surgery in spinal TB and to evaluate the outcome of various surgical procedures for kyphosis and neural outcome. Surgery in spinal tuberculosis is indicated for diagnostic dilemma, neural complications, and prevention of kyphosis progression. Up to 76% canal encroachment is compatible with a normal neurologic state as the spinal cord tolerates gradually developing compression. Patients with relatively preserved cord size, but with edema/myelitis and predominantly fluid compression on MRI respond well to nonoperative treatment. We believe patients with extradural compression by granulation tissue with little fluid component compressing or constricting the cord circumferentially with cord edema/myelitis or myelomalacia need early surgical decompression. Transthoracic transpleural anterior decompression and extrapleural anterolateral decompression have similar results in the dorsal spine. Instrumented stabilization helps prevent graft-related complications when postdebridement defects exceed two disc spaces (4-5 cm). Progression of kyphosis may occur in a short-segment disease despite instrumented stabilization. Its outcome in a long-segment disease needs observation. The correction of healed kyphosis requires multistage surgery and is fraught with complications. Prospective studies are needed to define surgical approach, steps, stages, problems, and obstacles to correct severe kyphosis in spinal TB.

Tuberculosis of the spine: a historical review.

Abstract: Almost all ancient civilizations described tuberculous bacilli in their old scripts, and these bacteria have been found in prehistoric skeletal remains The clinical availability of specific antitubercular drugs was the most important breakthrough in managing spinal tuberculosis Any attempt at surgical excision of the disease prior to the antitubercular era met with serious complications, dissemination of disease and high mortality (nearly 50%) Antitubercular drugs markedly improved the results of management by operative treatment Excellent healing of disease was also observed in those patients who were treated nonoperatively However, it took many years (1950-1970) for clinicians to appreciate the efficacy of antitubercular drugs Operations for spinal tuberculosis are now indicated less for control of disease (5-10% of all cases) than for complications, including nonresponding neural deficit (nearly 40% of neural complications), prevention or correction of severe kyphotic deformity, and for tissue diagnosis (approximately 5% of all cases) For a classic spondylodiscitis when surgery is required for debridement and decompression, an anterior approach through an extrapleural anterolateral route or through transpleural route is recommended Healthy posterior elements should not be jeopardized by surgery The real control of tuberculous disease requires a serious and sustained global effort to eliminate immunocompromised states, poverty, malnutrition, and overcrowding