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Unicondylar arthroplasty has reemerged as an option for isolated compartment knee arthritis. We have noticed an increase in the need for early revision of this construct at our revision center. This study sought to determine if the need for unicondylar revision has increased over time and what factors may have led to early failure. Revision total knee arthroplasties (TKAs) performed between 1990 and 1999 (period 1) were compared to TKAs performed between 2000 and 2008 (period 2). The prevalence of unicondylar revision, time to failure, and reasons for failure were calculated. Between 1990 and 1999, 425 revision TKAs were performed, 7 of which were uni-revisions (1.6%). These had been in place an average of 169 months (range, 12.9–478.6 months). Between 2000 and 2008, 744 revision TKAs were performed, 43 of which were uni-revisions (5.8%). These had been in place an average of only 36 months (range, 4.2–159.5 months). The dominant reasons for failure in period 1 included poly wear and loosening. Reasons for failure in period 2 were variable but included a number of technical errors. Early failure of unicondylar arthroplasty appears to be on the rise. Acknowledging that these patients came from an unknown pool, we are concerned that market pressure may have led to inappropriate patient selection and that surgical inexperience with this procedure may have led to the technical problems noted in period 2. Patients should be apprised of the possibility of early revision with this procedure.

Between 1986 and 1998, 81 total hip revisions were performed for recurrent instability. Twenty-three revisions were fixed cups to bipolars. Average follow-up was 50 months. Radiographic evaluation showed no significant osteolysis and average migration of 1.7 mm. The average postoperative Harris hip score was 74. All patients who underwent revision to a bipolar prosthesis had no further instability. Acetabular revision to a bipolar prosthesis provides stability in recurrent prosthetic hip instability.

This study describes the variance within a representative population of total knee arthroplasty (TKA) patients to provide guidance in improving coronal alignment. The authors retrospectively reviewed 250 preoperative full-length standing radiographs in a consecutive series of TKAs performed by one surgeon. The distal femoral resection was templated on each radiograph to establish a femoral mechanical anatomical (FMA) angle to guide resection. Mean FMA angle was 5.35°, with a wide variation in FMA angle ranging from 1° to 10°. Slightly more than half (56%) of patients had either a 5° or 6° FMA angle, which is concerning for surgeons using a fixed resection angle. Ninety percent of patients measured within the 5°±2° window. Similarly, 90.7% of patients measured within the 6°±2° window. However, nearly 10% of patients (9.75%) had measurements greater than 7° or less than 3°. This study reports a wide variance in the angle of resection required to establish proper femoral mechanical alignment in TKA. Surgeons should be cognizant of the numerous variables that play a role in TKA and influence overall coronal alignment. Many of these variables can be fully assessed by evaluating full-length standing leg radiographs preoperatively. With experience, templating long-leg films can be reproducible and informative in preparing for each surgical procedure. Routine reliance on a single fixed resection angle could result in malalignment in 10% of patients.

Osteoporotic fractures pose a significant health concern for postmenopausal women. Bisphosphonate therapy has been shown to decrease the risk of these fractures. The bisphosphonate alendronate was approved by the US Food and Drug Administration for use in the United States in 1995, but questions have recently arisen concerning low-energy subtrochanteric femur fractures sustained by chronic users. Although no definitive association or causality between bisphosphonates and these fractures has been established, numerous cautionary reports exist concerning the duration of use and safety of alendronate in osteoporotic patients. This article reports 3 occurrences of bisphosphonate-associated atypical femur fractures as an etiology of periprosthetic hip pain in the total hip arthroplasty (THA) patient. These fractures are particularly concerning because these patients are often not advised to protect their weight bearing simply due to a painful THA and may sustain a catastrophic failure if not followed closely. Several theories have been suggested concerning the pathophysiology of atypical low-energy subtrochanteric fractures following bisphosphonate use. Each patient described in this article carried a diagnosis of rheumatoid arthritis and underwent chronic medical therapy; each patient experienced a delay in the diagnosis and onset of therapy due to low suspicion for bisphosphonate-associated fracture. This problem may become more common in the clinical setting; therefore, one must be vigilant and aware of this etiology of periprosthetic hip pain.

With the demand for total joint arthroplasty and overall life expectancy increasing, there will be an increase in the need for revision arthroplasty surgeries. Given that revision joint surgeries are more demanding for both surgeon and patient with longer operative times, increased blood loss, and multiple patient comorbidities, the current mindset is that older patients who undergo a total hip revision or total knee revision have higher mortality rates than younger patients. We identified 1737 revision total joint patients who were at least 2 years postoperative for inclusion in the study. The overall perioperative mortality rate (defined as deaths occurring between 0 and 3 months following revision joint surgery) was calculated and then stratified by revision knee surgery, revision hip surgery, and age. In addition, mortality rates were compared for patients younger than 70 years, between 70 and 80 years and older than 80 years. The overall perioperative mortality rate after revision total hip or knee surgery was 0.7%. After stratifying by age, the perioperative mortality rate was 0.2% in patients younger than 70 years, 0.8% in patients 70 to 79 years, and 2.63% in patients older than 80 years. Of the 1737 patients, 541 died >1 year following their revision surgery at an average time to death of 6.9 years. The observed perioperative mortality rates following revision total joint surgery at a single center were extremely low among all age groups. Therefore, the age of patients undergoing revision surgery should not be the sole determinant of perioperative survival. Additionally, it appears that the mean postoperative survival noted here seems to justify the additional resources used in revision surgery regardless of age. As limited resources exert pressure on an already overburdened healthcare system, rationing of care for certain procedures may ensue using age as a specific criteria. This study should add clarity to this issue.

Knee instability is a common cause of prosthetic knee failure. This study sought to determine if synovial fluid analysis is a useful tool in diagnosing prosthetic knee instability. Aspirations were performed in 42 knees in which the diagnosis of instability was in doubt. This group was compared to 120 aspirated knees performed for other diagnoses, excluding infection. The average red blood cell count for the instability group was 79,365 (range, 300-960,000). The median red blood cell count was 9175 (interquartile range, 37,750-2337). In patients with other diagnoses, the average red blood cell count was 60,965 (range, 30-2,079,000). The median red blood cell count was 6200 (interquartile range, 27,525-2512; P=.56). This study confirms that unstable total knees have bloody effusions. The prognostic significance of this finding must be questioned, as patients with other diagnoses have similar findings. Physical examinations and stress radiographs remain the key determinants of prosthetic knee instability.

Rotating-platform knees are constructed of highly conforming polyethylene to reduce contact pressures that potentially cause wear. The mobile nature of the rotating platform can lead to bearing spin-out. The purpose of this study was to determine the prevalence of spin-out in a single series. A total of 426 knees in 393 patients were included in the study. All knees were implanted using a balanced-gap technique. The average follow up was 3.2 years. There were no cases of bearing spin-out. The author concludes that the balanced-gap technique reliably prevents spin-out in mobile-bearing total knee implantation. This implantation technique provides the potential wear benefits of the rotating platform design with a nominal bearing spin-out rate.

The primary objectives of total knee arthroplasty are to reduce pain, maximize range of motion (ROM), and provide stability through the gait cycle. Pain relief depends on proper ligamentous balancing and solid implantation. Solid implantation is typically assured through cementation, whereas soft-tissue balancing is vital to ensure maximum ROM and stability. Special consideration should be given to obtaining proper axial alignment, symmetric tension on the ligaments in both flexion and extension, and equalizing the flexion extension gaps. Strategies to ensure proper alignment and ligamentous balancing intraoperatively are discussed.