Reliability of templating with patient-specific instrumentation in total knee arthroplasty.

Magnetic resonance imaging (MRI) or computed tomography-based patient-specific instrumentation (PSI) may allow for reliable alignment and fewer outliers when compared with conventionally instrumented total knee arthroplasty (TKA). However, some authors have suggested that frequent intraoperative surgeon-directed changes may still be required. This study evaluated the accuracy of PSI to predict component sizing and alignment during TKA. A total of 84 patients (89 knees) who underwent a TKA using a PSI system were evaluated. An MRI-based preoperative plan of every knee was provided and approved by the surgeons. This demonstrated the proposed prosthetic component alignment, as well as the femoral, tibial, and bearing insert component size and position. Intraoperative changes to these components were prospectively recorded and compared with the computerized preoperative plan. Major changes were defined as any changes in femoral or tibial resection, size, and position of the components. Minor changes were defined as any change in the size of the polyethylene bearing insert. The preoperative plan was able to correctly predict the size of the implanted tibial and femoral component in 93 and 95.5% of the cases, respectively. Thirteen major intraoperative changes were made. In one knee, the proposed femoral resection was not acceptable (because of the presence of significant amount of osteophytes) and was abandoned in favor of a manual extramedullary guide. In another patient, the proposed femoral and tibial components were upsized. In two other patients, the femoral components were downsized, in four patients, the tibial components were downsized, and in another patient, it was upsized. There were also 16 minor changes, which included 2-mm upsizing of the polyethylene liner in 13 knees and 4-mm upsizing in 3 knees. Surgical experience is necessary to recognize improper component size, incorrect surgical resection, or nonideal alignment when performing TKA using PSI. The authors believe that the design and manufacture of PSI combined with a comprehensive templating resulted in excellent intraoperative concordance of the preoperative plan at the default settings with minimal changes.

Peroneal nerve dysfunction after total knee arthroplasty: characterization and treatment.

The purpose of this study was to report on the presentation, evaluation, treatment, and outcome of patients who had a peroneal nerve dysfunction after total knee arthroplasty. Six patients were unable to achieve adequate range of motion after physical therapy, and the remaining 5 patients had sensory symptoms that interfered with daily activities despite adequate range of motion. All 11 patients had abnormal electrodiagnostic testing but had intact motor strength and were treated with surgical decompression of the nerve. The patients with motion problems had a mean increase in range of motion of 40 ° (range, 20 °-70 °) at final follow-up. All patients with dominant sensory symptoms had a resolution of leg and foot pain after treatment. Orthopedic surgeons should be aware of peroneal nerve dysfunction as a possible cause of unsatisfactory rehabilitation and/or persistent atypical lateral leg pain after total knee arthroplasty.

Osteonecrosis is not a predictor of poor outcomes in primary total hip arthroplasty: a systematic literature review.

The primary goals of this critical literature review were to determine whether revision rates of primary total hip arthroplasty in patients with osteonecrosis differ based on the underlying associated risk factors and diagnoses, whether the outcomes of this procedure have improved over the past two decades, and to compare outcomes based on study level of evidence. A systematic literature review yielded 67 reports representing 3,277 hips in 2,593 patients who had a total hip arthroplasty for osteonecrosis of the femoral head. Stratification of outcomes by associated risk factors or diagnoses revealed significantly lower revision rates in patients with idiopathic disease, systemic lupus erythematosus, and after heart transplant, and significantly higher rates in patients with sickle cell disease, Gaucher disease, or after renal failure and/or transplant. There was a significant decrease in revision rates between patients operated upon before 1990 versus those in 1990 or later, with rates of 17% and 3%, respectively. The results for arthroplasties performed in 1990 or later were similar to those for all hips in publicly reported national joint registries. Certain risk factors were associated with higher revision rates in patients with osteonecrosis who were treated by total hip arthroplasty. However, most patients (82%) do not have these associated negative risk factors. Overall, this critical literature review provides evidence that osteonecrosis itself, or when associated with the most common risk factors and/or diagnoses, is not associated with poor outcomes in total hip arthroplasty.

The natural history of untreated asymptomatic osteonecrosis of the femoral head: a systematic literature review.

BACKGROUND: An asymptomatic hip with osteonecrosis is typically discovered as the contralateral hip of a patient with one symptomatic joint. Treatment of the asymptomatic hip is controversial. While some authors claim a benign natural history, others have reported a rate of femoral head collapse exceeding 50%. The purpose of this report was to systematically review the published literature regarding asymptomatic osteonecrosis of the femoral head to evaluate the overall prevalence of progression to symptomatic disease and/or femoral head collapse as well as to determine whether various radiographic and demographic factors influence progression of the disorder. METHODS: A comprehensive literature search was performed to identify prognostic studies evaluating asymptomatic hip osteonecrosis. Demographic, radiographic, and outcome data were extracted from all relevant studies. The prevalence of progression to symptomatic disease and/or femoral head collapse was determined. Next, outcomes were stratified by lesion size, lesion location, radiographic stage, associated risk factors and/or disease, and the level of evidence of the study. RESULTS: Sixteen studies that included a total of 664 hips were available for an analysis of outcomes. Overall, 394 hips (59%) had progression to symptoms or collapse. Differences in outcomes based on lesion size, lesion location, and radiographic stage at the time of diagnosis were seen. Small, medially located lesions had the best prognosis, with a prevalence of collapse of <10%. Patients with sickle cell disease had the highest frequency of progression, and those with a history of systemic lupus erythematosus had the most benign course. CONCLUSIONS: Data extracted from previously published studies suggest that asymptomatic osteonecrosis has a high prevalence of progression to symptomatic disease and femoral head collapse. While small, medially located lesions have a low rate of progression, the natural history of asymptomatic medium-sized, and especially large, osteonecrotic lesions is progression in a substantial number of patients. For this reason, it may be beneficial to consider joint-preserving surgical treatment in asymptomatic patients with a medium-sized or large, and/or laterally located, lesion.

Scientific evidence for minimally invasive total knee arthroplasty.

Total knee arthroplasty is often considered one of the most successful surgical operations, with implant survival rates as high as 95% reported over follow-up periods of 15 to 20 years. Despite these excellent reported results, some level of outcome dissatisfaction is reported in a considerable numbers of patients. Minimally invasive surgical techniques have been developed in an attempt to reduce or eliminate the surgical factors perceived to contribute to this dissatisfaction. An overview of minimally invasive total knee arthroplasty, with specific focus on level I (prospective, randomized) studies when available is presented along with an examination of how the published literature supports some of the more commonly stated benefits and drawbacks of minimally invasive techniques. Minimally invasive total knee arthroplasty generally encompasses the following goals: reduced skin incision size, minimal or no incision of the extensor muscles and quadriceps tendon, minimal or no eversion of the patella, the use of downsized instrumentation, making bone cuts in situ, and minimal dislocation of the knee joint. Five principal surgical approaches have been developed that incorporate these aims, and, to date, four level I studies have been reported that compare the results of one or more of these techniques to traditional total knee arthroplasty. Three of these four studies showed no knee score differences at 3 months; one study showed higher scores at up to 9 months follow-up. In the opinion of the authors, these surgeons may have still been on their learning curve. Further studies that examine patients treated by surgeons who have mastered minimally invasive techniques may provide further insight into the true benefits and drawbacks of these techniques.

Surgical techniques for minimally invasive exposures for total knee arthroplasty.

The anterior medial parapatellar approach has long been the standard approach for total knee arthroplasty. Although this approach uses a simple, reproducible technique, some patients have reported lasting functional limitations after the surgery. Recently, marked interest has arisen in developing minimally invasive surgical approaches, implants, and instruments with the aim of improving patient outcomes. Five principal surgical approaches-the mini medial parapatellar, the quadriceps muscle-sparing, the mini-midvastus, the mini-subvastus, and the direct lateral-are most commonly used with minimally invasive techniques. Understanding the benefits and drawbacks of each approach as well as the reported results will aid orthopaedic surgeons in selecting the best treatment option for their patients.

Percutaneous drilling for the treatment of atraumatic osteonecrosis of the ankle.

Atraumatic osteonecrosis of the ankle can be severely debilitating and can lead to joint collapse. A relatively new technique of percutaneous drilling has previously been used to relieve the symptoms of osteonecrotic hips and knees. The purpose of the present study was to examine the results of this technique when used to treat osteonecrosis of the ankle. Between September 2002 and June 2005, the senior author (M.A.M.) treated and prospectively followed 44 symptomatic osteonecrotic ankles (31 patients) using this drilling technique. The series included 23 (74.2%) women and 8 (25.8%) men with a mean age of 43 +/- 11 years. Arthrodesis had been recommended for 14 (45.2%) of these patients (20 [45.5%] ankles). At a mean follow-up duration of 45 +/- 12 months, 40 (91%) ankles had achieved a successful clinical outcome. The mean American Orthopaedic Society of Foot and Ankle Society Ankle and Hindfoot score increased from 42 +/- 5 points preoperatively to 88 +/- 10 points postoperatively, and this difference was statistically significant (P < .0001). There were no perioperative complications, although 3 ankles subsequently collapsed and required arthrodesis. The percutaneous drilling technique appears to be a useful method for the relief of symptomatic ankle osteonecrosis.

Femoral notch stenosis caused by soft tissue impingement in semi or open-box posterior-stabilized total knee arthroplasty.

The goal of this study was to evaluate the treatment of femoral notch stenosis caused by soft tissue hypertrophy. Nineteen patients (19 knees) were evaluated arthroscopically for late-onset clinical findings of progressive loss of extension, pain, and/or crepitus after posterior-stabilized total knee arthroplasty. The patients had similar pathology that included marked hypertrophic soft tissue in the posterior-stabilized box impinging against the polyethylene post. Patients underwent arthroscopic débridement, with a mean increase in Knee Society pain scores of 39 points (range, 6-76 points), a mean increase of Knee Society function scores of 37 points (range, 10-72 points), and a mean increase in range of motion of 12° (range, -15° to 61°). One patient had a recurrence of symptoms at final follow-up, which was treated with reoperation. In patients with normal radiographs and clinically stable knees, the findings of progressive loss of extension with pain and crepitus may merit further evaluation. If notch stenosis is identified, arthroscopic débridement usually leads to a satisfactory result, at least at short-term follow-up.

Minimally invasive total knee arthroplasty using the contralateral knee as a control group: a case-control study.

The primary purpose of this study was to compare clinical and functional results of bilateral total knee arthroplasties in which a conventional total knee replacement was initially performed on one knee and a minimally invasive total knee replacement was later performed on the contralateral side. Operative factors, clinical and radiographic outcomes, and quadriceps muscle strength were evaluated in twenty-five patients (50 total knee arthroplasties). Twenty-one of the 25 patients preferred the minimally invasive approach. Knee society objective scores and range-of-motion were significantly greater in the minimally invasive group. Isokinetic testing demonstrated statistically improved quadriceps muscle strength in the minimally invasive technique group compared to the standard approach at both 12 weeks and one year postoperatively. Radiographic analysis did not reveal differences in alignment variables between the two approaches. The results of this study suggest that minimally invasive total knee arthroplasty offers superior short-term as well as possible long-term results.

Bicondylar spontaneous osteonecrosis of the knee: A case report.

Spontaneous osteonecrosis of the knee was originally described as a distinct disorder in 1968. Characteristic imaging findings and distinctive demographic and clinical factors help distinguish this disease from other osteonecrotic conditions, with which it can be confused. This report presents a rare, atypical case of bicondylar spontaneous osteonecrosis of the knee in a young patient, and highlights the importance of a clear understanding of the clinical and radiographic characteristics of this condition to accurately diagnose and treat it when evaluating osteonecrotic lesions of the knee.

Minimally invasive total knee arthroplasty: pitfalls and complications.

Despite reports of complications, there has been tremendous interest in using minimally invasive surgery (MIS) for total knee arthroplasty (TKA). Over the past 10 years, we have used an MIS approach for all TKAs. In the study described here, we examined the complications of the first 1000 of these TKAs. These cases involved a minimal incision (mean, 10 cm), a quadriceps muscle-sparing approach, and a non-patellar-everting technique. The complications assessed included manipulations, reoperations, and component revisions. We also analyzed for deviations in radiographic alignment or radiographic failures. There were 45 clinical complications-25 manipulations under anesthesia, 12 arthroscopic procedures for painful patellofemoral crepitus (mostly for an initially nonvisualized retained lateral band), and 8 operative explorations for various component problems. Radiographically, there were 3 impending component failures-2 tibial and 1 femoral. Excluding manipulations, there was a significant decrease in operative complication rate from the first 200 cases (6.0%) to the next 800 cases (1.0%), with overall complication rates similar to those of a control cohort treated with traditional surgical techniques. From this analysis, the major concern was potential tibial component loosening, which may be related to decreased exposure and possibly poor cement pressurization. Despite the low complication rate, this study yielded insights into further potential improvements in using this MIS technique for TKAs.

Early failure of a unicompartmental knee arthroplasty design with an all-polyethylene tibial component.

Refined prosthetic designs and surgical techniques for unicompartmental knee arthroplasty have recently been associated with improved outcomes. The purpose of the present study was to evaluate the clinical and radiographic outcomes of the EIUS unicompartmental design, which has an all-polyethylene tibial component, and to compare these outcomes with published reports of other unicompartmental prostheses. Between February 2002 and March 2005, 113 patients (144 knees) underwent a medial unicompartmental knee arthroplasty, all performed by a single surgeon who used the EIUS prosthesis. At a mean follow-up of 36 months (range, 24-54 months), the mean Knee Society objective and functional scores improved from 55 points (range, 31-77 points) and 49 points (range, 35-60 points) to 92 points (range, 45-100 points) and 89 points (range, 10-100 points), respectively. The implant survival rate was 89%, with 16 knees either revised or scheduled for revision. The reasons for revision included aseptic loosening of the tibial component (eight knees), progressive symptomatic patellofemoral disease (four knees), and tibial component subsidence (four knees). Multiple regression analysis revealed that age, gender, and body mass index were not significantly correlated with success or failure of this design, although nine of the 16 patients who required revision were obese. This prosthesis was associated with higher revision rates than components which utilize metal-backed implants. Further modifications in the design, indications, or technique may be necessary to improve outcomes of this unicompartmental knee arthroplasty system.

Incidence and cost of intraoperative waste of hip and knee arthroplasty implants.

Many strategies have been reported for decreasing the cost of orthopedic procedures, but prosthetic waste has not been investigated. The purpose of this study was to characterize the cost of intraoperative waste of hip and knee implants. A regional prospective assessment was performed, evaluating the reasons for component waste, the cost of the wasted implants, and where the cost was absorbed (hospital or manufacturer). Implant waste occurred in 79 (2%) of 3443 procedures, with the surgeon and operating room staff bearing primary responsibility in 73% of occurrences. The annualized cost was $109 295.35, with 67% absorbed by hospitals. When extrapolated to the whole of the United States, the annual cost to hospitals would be $36,019,000 and is estimated to rise to $112,033,000 by 2030, representing a potential target for educational programs and other cost containment measures.

Joint-preserving surgical treatment of spontaneous osteonecrosis of the knee.

BACKGROUND: To date, reports of surgical treatment of spontaneous osteonecrosis of the knee (SPONK) refractory to non-operative treatment have primarily focused on knee arthroplasty. This report presents an overview of the characteristics of SPONK and reports our experience with joint-preserving surgical treatment of this condition. METHODS: Fifteen patients who had joint-preserving surgery after failed non-operative modalities were studied. These patients were treated at a single center between January 1998 and September 2006 with a combination of arthroscopy and core decompression, or osteochondral autograft transfers. RESULTS: Thirteen of the 15 knees (87%) had knee joint survival with a mean Knee Society Score of 81 points (range 45­100 points) at a mean follow-up of 40 months (range 9­120 months). Five of seven knees treated with core decompression had a successful clinical outcome. One of the patients who failed core decompression later underwent osteochondral autograft transfer, and eight of nine knees treated with this modality had a successful outcome. CONCLUSION: Overall, these results demonstrate that joint-preserving surgical treatment can successfully postpone the need for knee arthroplasty in selected patients with pre-collapse SPONK.

Static progressive stretch improves range of motion in arthrofibrosis following total knee arthroplasty.

Arthrofibrosis is a relatively common complication after total knee arthroplasty that negatively affects function and quality of life. Static progressive stretching is a technique that has shown promising results in the treatment of contractures of the elbow, ankle, wrist and knee. This study evaluated a static progressive stretching device as a treatment method for patients who had refractory knee stiffness after total knee arthroplasty. Twenty-five patients who had knee stiffness and no improvement with conventional physical therapy modalities were treated with the device. After a median of 7 weeks (range, 3-16 weeks), the median increase in range of motion was 25 degrees (range, 8-82 degrees). The median gain in knee active flexion was 19 degrees (range, 5-80 degrees). Ninety-two percent of patients were satisfied with the results. The authors believe static progressive stretching devices may be an effective method for increasing the ranges of motion and satisfaction levels of patients who develop arthrofibrosis after total knee arthroplasty.

An arthroscopic technique to enhance visualization during total hip arthroplasty.

This technical note describes the use of an arthroscope or endoscope to enhance visualization during minimally invasive total hip arthroplasty. The arthroscope/endoscope is used to verify seating of the components and to look for potential impingements, loose bodies, or fractures. This technique was successfully used to identify and address 2 bony or soft tissue impingements as well as a calcar fracture that might otherwise have been missed. Although further study is necessary, we believe that this technique might reduce postoperative complications and improve clinical outcomes of total hip arthroplasty.

Intraoperative waste of trauma implants: a cost burden to hospitals worth addressing?

OBJECTIVES: The purposes of this study were to assess the incidence of intraoperative trauma implant waste in a regional territory of the United States and to assess its impact on costs. METHODS: The total number of procedures using a single device manufacturer's orthopaedic trauma implants in one geographic region and number of occurrences of intraoperative orthopaedic trauma implant waste were recorded prospectively from 74 contiguous hospitals over a period of 18 months along with the individual responsible for the waste (surgeon, vendor representative, or operating room staff), the cost of the wasted implant, and whether the hospital paid for the implant. Hospitals were stratified into teaching or community institutions. The collected data were then aggregated and analyzed for overall incidence and cost as well as cost per trauma procedure. RESULTS: Implant waste occurred in 37 of 6531 procedures (0.6%) with 16 of the centers (21.6%) reporting at least one occurrence and 95% attributed to the surgeon or operating room staff. Community hospitals were found to have a significantly higher incidence of implant waste as compared with teaching hospitals. Hospitals absorbed 74% of the wasted implant costs ($20,357 over the study period). This expense represented a mean additional cost of $3.12 per orthopaedic trauma procedure performed. CONCLUSIONS: There is a small but notable annual incidence and cost of orthopaedic trauma implant waste in the study region with the majority of this cost borne by the hospitals. However, implant waste occurs infrequently and represents a very small cost to hospitals per procedure. Educational programs and other strategies to reduce its incidence are unlikely to yield any substantial cost savings.