S. David Stulberg

Predicting total knee replacement pain: a prospective, observational study.

To describe the natural history of pain after total knee arthroplasty and to identify factors predicting excessive postoperative pain, we used a prospective, observational study assessing clinical and radiographic variables preoperatively and at 1, 3, 6, and 12 months after knee replacement. Data sources included the visual analog pain scale and other measures of patient health, psychologic state, and component reliability. Regression analyses were conducted to identify specific factors predictive of postoperative pain, controlling for inequality of variables, and confirmed using regression diagnostics. For 116 patients (149 knees; mean age, 66 years; 55.2% women), significant pain was reported by 72.3%, 44.4%, 22.6%, 18.4%, and 13.1%, respectively. No intergroup differences existed for anesthesia, weight, age, or gender. Patients with greater preoperative pain had more postoperative pain, used more home therapy, and postoperative manipulations. Preoperative depression and anxiety were associated with heightened pain at 1 year. Pain after knee replacement resolves quickly, declining to approximately 1/2 by 3 months. However, one in eight patients report moderate to severe pain 1 year after surgery despite an absence of clinical or radiographic abnormalities. Development of office-based preoperative screening tools and interventions for these patients may reduce postoperative costs and improve patient-perceived outcomes.

Computer-assisted navigation in total knee replacement: results of an initial experience in thirty-five patients.

The success of total knee replacement surgery depends on several factors, including proper patient selection, appropriate implant design, correct surgical technique, and effective perioperative care. The outcome of total knee replacement surgery is particularly sensitive to variations in surgical technique 1-9. Incorrect positioning or orientation of the implant and improper alignment of the limb can lead to accelerated implant wear and loosening as well as suboptimal functional performance. A number of studies have suggested that alignment errors of >3° are associated with more rapid failure and less satisfactory functional results after total knee arthroplasty 1,10-20. Recent studies have also emphasized that the most common cause for revision total knee replacement is error in surgical technique. Mechanical alignment guides have improved the accuracy with which implants can be inserted. Although mechanical alignment systems are continually being refined, errors in implant and limb alignment continue to occur. It has been estimated that errors in tibial and femoral alignment of >3° occur in at least 10% of total knee arthroplasties, even when performed by experienced surgeons using mechanical alignment systems of modern design. Mechanical alignment systems have fundamental problems that limit their ultimate accuracy. The accuracy of preoperative planning is limited by the errors inherent in standard radiographs. It is difficult to determine accurately, with standard instrumentation, the correct location of crucial alignment landmarks (e.g., the center of the femoral head, the center of the ankle). Moreover, mechanical alignment and sizing devices presume a standardized bone geometry that may not apply to a specific patient. Even the most elaborate mechanical instrumentation systems rely on visual inspection to confirm the accuracy of limb and implant alignment and stability at the conclusion of the total knee replacement procedure. Computer-based alignment systems have been developed to address the …

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

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.

Functional Outcome and Patient Satisfaction in Total Knee Patients Over the Age of 75

Seventy-four patients, age 75 or older, who had undergone 98 primary total knee arthroplasties were evaluated in a retrospective cohort study, with validated questionnaires that assessed self-reported pain, physical function, mental health, and satisfaction. Average follow-up period was 34 months (range, 12-67 months). Overall, 90.8% reported improvement, 88.8% were satisfied with the results of surgery, and 91.8% felt they had made the right decision. Dissatisfaction with the results correlated with poorer mental health scores, decreased physical function, and increased bodily pain scores (P < .05). Satisfaction was correlated with better pain scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and SF-36 (P < .05) but not with Hospital for Special Surgery scores (P = .328). Poor surgical results leading to revision surgery (5%) were associated with preoperative deformity greater than 20 degrees. Based on this patient-assessed outcome analysis, total knee arthroplasty is a worthwhile and beneficial procedure in the elderly.

Prospective examination of pain-related and psychological predictors of CRPS-like phenomena following total knee arthroplasty: a preliminary study

&NA; We hypothesized that preoperative emotional distress and pain intensity would predict the occurrence of signs and symptoms of complex regional pain syndrome (CRPS) following total knee arthroplasty (TKA). Depression (Beck Depression Inventory, BDI), anxiety (State Trait Anxiety Inventory, STAI), pain (McGill Pain Questionnaire–Short Form, MPQ), and signs/symptoms meeting IASP criteria for CRPS were assessed preoperatively, and at 1‐, 3‐, and 6‐months postoperatively in 77 patients undergoing TKA. The prevalence of subjects fulfilling CRPS criteria was 21.0% at 1 month, 13.0% at 3 months, and 12.7% at 6 months postoperative. Higher preoperative scores on the STAI predicted positive CRPS status at 1‐month follow‐up (P<0.05), with a similar non‐significant trend for preoperative BDI scores (P<0.10). Diagnostic sensitivity for the STAI was good (0.73), with moderate specificity (0.56). Neither measure predicted CRPS at later follow‐up (P>0.10). Greater preoperative pain intensity predicted positive CRPS status at 3‐month (MPQ‐Sensory and MPQ‐Affective; P<0.01) and 6‐month (MPQ‐Sensory) follow‐up (P<0.01), but not at 1‐month (P>0.10). Diagnostic sensitivity was high (0.83–1.00), with moderate specificity (0.53–0.60). Post‐TKA patients with CRPS were more depressed at 1‐month follow‐up (P<0.05) and more anxious at 6‐month follow‐up (P<0.05) than patients with ongoing non‐CRPS pain (all other comparisons non‐significant, P>0.10). Overall, results indicate that CRPS‐like phenomena occur in a significant number of patients early post‐TKA; however, it is not associated with significantly greater complaints of postoperative pain. There appears to be a modest utility for preoperative distress and pain in predicting CRPS signs and symptoms following TKA, although false positive rates are relatively high.

Use of helical computed tomography for the assessment of acetabular osteolysis after total hip arthroplasty.

Background: Acetabular osteolysis is a major problem affecting long-term survival of total hip prostheses. Since lytic lesions may be asymptomatic until extensive bone loss has occurred, early detection of lytic lesions is important. The purposes of this study were to determine the efficacy and potential role of high-resolution helical (or spiral) computed tomography with metal-artifact minimization in the early detection of osteolysis of the pelvis and to use the method to determine if there was a relationship between the extent of osteolysis and the amount of polyethylene wear. Methods: Forty patients (fifty hips) who had undergone primary cementless total hip arthroplasty between 1988 and 1994 were evaluated as part of an ongoing prospective study. These patients had a history of high-level activity that was believed to place them at increased risk for accelerated polyethylene wear. The most recent follow-up radiographs were compared with the three-month postoperative radiographs. Helical computed tomography scans with metal-artifact minimization were made, and evidence of osteolytic lesions on these scans was compared with that on the radiographs. Two-dimensional wear analysis was performed with use of digitized radiographs, and the results were compared with loss of bone volume as calculated from the computed tomography scans. Results: Acetabular lysis was identified on the radiographs of sixteen hips and on the computed tomography scans of twenty-six hips. Radiographs underestimated the extent of the lysis in thirteen of the sixteen hips. There was no correlation (r = 0.036) between linear wear and the measured volume of bone loss, with the numbers available. On the basis of the amount of lysis seen on the computed tomography scans, one patient underwent a revision procedure. Conclusions: Helical computed tomography with metal-artifact minimization is more sensitive for identifying and quantifying osteolysis after total hip arthroplasty than is plain radiography. Since computed tomography scans show both the extent and the location of lytic lesions, they are useful to guide treatment decisions as well as to assist in planning for surgical intervention, when needed, in patients with suspected osteolysis.

Outcome of hip and knee arthroplasty in persons aged 80 years and older

Recent studies have established the cost effectiveness and safety of total joint arthroplasties. As the population ages, it is important to determine whether these procedures are equally beneficial in the elderly. The short term safety and efficacy of total hip and knee arthroplasties in subjects 80 years of age and older was evaluated. Between 1988 and 1993, preoperative and postoperative physical and functional information was collected on 99 consecutive elective hip and knee arthroplasties in subjects 80 years of age or older. These data were compared with those derived from a younger otherwise matched control group. Data collected included subject demographics and characteristics, information concerning the acute and postacute hospital stay, comorbid conditions, postoperative complications, discharge disposition, Hospital for Special Surgery knee and Harris hip scores, pain scores, and functional capacity. The average age of the subjects was 83 years; osteoarthritis was the most common diagnosis; and the average followup was 25 months. Complication rates and length of stay in acute care facilities were not significantly different than for the control group. Mean preoperative Hospital for Special Surgery knee and Harris hip scores were 58 and 60, respectively, with postoperative scores of 77 and 88, respectively. Pain dramatically improved with 98% of total knee arthroplasty and 100% of total hip arthroplasty subjects reporting mild or no pain at followup. Preoperatively, none of the knee or hip subjects could walk unlimited distances. Postoperatively 51% of the total knee arthroplasty and 54% of the total hip arthroplasty subjects could walk more than five blocks; 71% of the total knee arthroplasty and 86% of the total hip arthroplasty subjects walked with a cane or no assistive device. The most dramatic postoperative functional gains were seen in the most disabled subjects. Total charges of care for patients 80 years of age and older was slightly greater than for a younger group. It was established that total joint arthroplasty can be performed safely in patients 80 years of age and older, promising excellent pain relief and improved functional outcome.

Registration and immobilization in robot-assisted surgery.

Robotic systems for computer-assisted surgery involve both tools and techniques that are new to the surgical arena. Registration and immobilization in particular are key problems. Registration is the spatial alignment of the coordinate frames of the robot, an anatomic object (e.g., a bone), and the preoperative plan (a computer model). Immobilization is necessary to maintain that alignment. We discuss various approaches to registration and immobilization and solutions appropriate for an orthopedic surgical system.

Computer-Assisted Surgery versus Manual Total Knee Arthroplasty: A Case-Controlled Study

The use of computer-assisted surgery by orthopaedists experienced in the performance of total knee arthroplasty results in better overall limb and implant alignment and fewer outliers as compared with the findings after manual total knee arthroplasty1-8. However, we are not aware of any studies that have established whether these improvements in alignment accuracy are associated with superior clinical and patient-perceived functional results. In addition, we are not aware of any studies that have examined the potential training effects that occur when experienced surgeons use these techniques. Computer-assisted surgery may offer experienced surgeons the potential to improve their technique and their ability to perform total knee arthroplasty manually through intraoperative training effects provided by working with computer-assisted surgery. For example, in severely obese patients, proper limb alignment may not be readily apparent on initial visualization or with use of a standard mechanical alignment system. However, through the use of a navigation system, it is possible to obtain real-time alignment measurements during the course of the surgical procedure. The intraoperative feedback provided by the navigation system offers the surgeon the ability to adjust his or her perception and assessment of proper limb and implant alignment. This training effect may result in a more accurate total knee arthroplasty performed with use of manual instrumentation. The first goal of the present study was to compare the clinical, patient-perceived functional, and radiographic results of manually performed total knee arthroplasty with the results obtained with use of computer-assisted surgery techniques. The second goal was to assess the impact of extensive experience with computer-assisted surgery on the manual technique of an experienced total knee arthroplasty surgeon. Seventy-eight consecutive total knee arthroplasties were performed by a single surgeon (S.D.S.) who had extensive prior experience with both computer-assisted surgery and manual total knee arthroplasty. Of …

Radiographic and Navigation Measurements of TKA Limb Alignment Do Not Correlate

AbstractPrecise pre- and postoperative anatomic measurements are necessary to plan, perform, and evaluate total knee arthroplasty (TKA). We evaluated the relationship between radiographic and navigation alignment measurements, identified sources of error in radiographic and navigated alignment assessment, and determined the differences between desired and clinically accepted alignment. Fifty-eight computer-assisted TKAs were performed and limb alignment measurements were recorded both pre- and postoperatively with standard radiographs and with an intraoperative navigation system. Intraoperative navigation produced consistent navigation-generated alignment results that were within 1° of the desired alignment. The difference between preoperative radiographic and navigation measurements varied by as much as 12° and the difference between postoperative radiographic and navigation measurements varied by as much as 8°. This discrepancy depended on the degree of limb deformity. Postoperative radiographic measurements have inherent limitations. Navigation can generate precise, accurate, and reproducible alignment measurements. This technology can function as an effective tool for assessing pre- and postoperative limb alignment and relating intraoperative alignment measurements to clinical and functional outcomes. Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.