Murray J. Penner

Elution Characteristics of Vancomycin and Tobramycin Combined in Acrylic Bone-Cement

Combining two antibiotics in antibiotic-loaded bone-cement is common in clinical practice. As the effect this has on elution characteristics is unknown, an in vitro quantitative elution study was carried out. Three groups of five antibiotic-loaded cement disks were prepared and placed in individual saline baths for 5 weeks. The elution of tobramycin from the disks in the study group (containing 2.4 g tobramycin and 1.0 g vancomycin per 40-g packet of Palacos-R cement powder [Smith & Nephew Orthopaedics, Memphis, TN]) was increased by 68% over that of the tobramycin control disks (2.4 g tobramycin only) (P = .024). The release of vancomycin from the study group disks was increased by 103% over the vancomycin control disks (1.0 g vancomycin only) (P = .007). Combining two antibiotics in bone-cement improves elution of both antibiotics in vitro and may translate into enhanced elution in vivo.

Comparison of Health-Related Quality of Life Between Patients with End-Stage Ankle and Hip Arthrosis

BACKGROUND End-stage ankle arthrosis is one of the leading causes of chronic disability in North America. Information on this condition is limited. The amount of pain and the reduction in health-related quality of life and function have not been quantified with use of universal outcome measures. The purpose of the present study was to compare the extent of pain, loss of function, and health-related quality of life in two cohorts of patients waiting for the surgical treatment of end-stage ankle or hip arthrosis. METHODS One hundred and thirty patients with end-stage ankle arthrosis who were awaiting total ankle arthroplasty or ankle arthrodesis were recruited through a Canadian Orthopaedic Foot and Ankle Society multicenter study. All patients prospectively completed the Short Form-36 (SF-36) generic outcome instrument. This cohort was compared with a similar cohort of 130 patients with end-stage hip arthrosis, randomly selected from an existing prospective joint replacement database, who had completed an SF-36 questionnaire prospectively from 2000 to 2005. RESULTS In both groups, the scores for all SF-36 subscales were approximately two standard deviations below normal population scores. Patients with ankle arthrosis had significantly worse mental component summary scores (p < 0.05), role-physical scores (p < 0.05), and general health scores (p < 0.05). Patients with hip arthrosis reported significantly lower physical function scores (p < 0.05), although the SF-36 physical component summary score was not significantly different between the two groups. The SF-36 physical component summary, bodily pain, vitality, role-emotional, social functioning, and mental health subscale scores were equally affected in both cohorts. CONCLUSIONS The mental and physical disability associated with end-stage ankle arthrosis is at least as severe as that associated with end-stage hip arthrosis.

The in vitro elution characteristics of antibiotic-loaded CMW and Palacos-R bone cements.

An in vitro study was carried out comparing the elution characteristics of Palacos-R and CMW acrylic cements. Three groups of 6 antibiotic-loaded cement disks were prepared, incorporating 1.0 g vancomycin and 2.4 g tobramycin per 40 g packet of cement. Palacos-R bone cement was used for group 1, CMW 1 for group 2, and CMW 3 for group 3. The disks were placed in saline baths for 9 weeks. The baths were periodically sampled and elution rates calculated. CMW 1 released 24% less tobramycin and 36% less vancomycin than Palacos-R over the total study period (P < .05). CMW 3 released 34% less tobramycin and 38% less vancomycin than Palacos-R (P < .05). There was no significant difference in antibiotic release between CMW 1 and CMW 3. The in vitro elution characteristics of Palacos-R are superior to CMW.

Responsiveness and Validity of the SF-36, Ankle Osteoarthritis Scale, AOFAS Ankle Hindfoot Score, and Foot Function Index in End Stage Ankle Arthritis

Background: We examined four commonly used scores, the SF-36, the Ankle Osteoarthritis Scale (AOS), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score, and the Foot Function Index (FFI) to determine their responsiveness and validity. Methods: Patients with end stage ankle arthritis were recruited into a prospective multicenter cohort study and baseline and one year outcome scores were compared. The Standardized Response Mean and Effect Size for the AOS, AOFAS, and FFI were calculated and the three region- or disease-specific scores were compared with the SF-36 to determine their criterion validity. Results: All four scores showed acceptable responsiveness, and when using the validated SF-36 as the standard the three region or disease specific scores all showed similar criterion validity. Conclusion: All four scores are responsive and can be considered for use in this population. The objective component of the AOFAS Ankle Hindfoot Score may make it harder to perform than the other three scores which have subjective components only, and as yet its objective component has not been shown to demonstrate reliability. We recommend use of a purely subjective score such as the Ankle Osteoarthritis Scale or Foot Function Index as the region- or disease-specific score of choice in this population. As the SF-36 shows acceptable responsiveness, using it alone could also be considered. Level of Evidence: II, Prospective Comparative Study

Intermediate-Term Results of Total Ankle Replacement and Ankle Arthrodesis

BACKGROUND Surgical treatments for end-stage ankle arthritis include total ankle replacement and ankle arthrodesis. Although arthrodesis is a reliable procedure, ankle replacement is often preferred by patients. This prospective study evaluated intermediate-term outcomes of ankle replacement and arthrodesis in a large cohort at multiple centers, with variability in ankle arthritis type, prosthesis type, surgeon, and surgical technique. We hypothesized that patient-reported clinical outcomes would be similar for both procedures. METHODS Patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database were treated with total ankle replacement (involving Agility, STAR, Mobility, or HINTEGRA prostheses) or ankle arthrodesis by six subspecialty-trained orthopaedic surgeons at four centers between 2001 and 2007. Data collection included demographics, comorbidities, and the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) scores. The preoperative and latest follow-up scores for patients with at least four years of follow-up were analyzed. Sensitivity analyses excluded ankles that had undergone revision. A linear mixed-effects regression model compared scores between the groups, adjusting for age, sex, side, smoking status, body mass index, inflammatory arthritis diagnosis, baseline score, and surgeon. RESULTS Of the 388 ankles (281 in the ankle replacement group and 107 in the arthrodesis group), 321 (83%; 232 ankle replacements and eighty-nine arthrodeses) were reviewed at a mean follow-up of 5.5 ± 1.2 years. Patients treated with arthrodesis were younger, more likely to be diabetic, less likely to have inflammatory arthritis, and more likely to be smokers. Seven (7%) of the arthrodeses and forty-eight (17%) of the ankle replacements underwent revision. The major complications rate was 7% for arthrodesis and 19% for ankle replacement. The AOS total, pain, and disability scores and SF-36 physical component summary score improved between the preoperative and final follow-up time points in both groups. The mean AOS total score improved from 53.4 points preoperatively to 33.6 points at the time of follow-up in the arthrodesis group and from 51.9 to 26.4 points in the ankle replacement group. Differences in AOS and SF-36 scores between the arthrodesis and ankle replacement groups at follow-up were minimal after adjustment for baseline characteristics and surgeon. CONCLUSIONS Intermediate-term clinical outcomes of total ankle replacement and ankle arthrodesis were comparable in a diverse cohort in which treatment was tailored to patient presentation; rates of reoperation and major complications were higher after ankle replacement.

Impact of Complications in Total Ankle Replacement and Ankle Arthrodesis Analyzed with a Validated Outcome Measurement

BACKGROUND Major modifications in the design and techniques of total ankle replacement have challenged the perception that ankle arthrodesis is the treatment of choice for end-stage ankle arthritis. High complication and revision rates have been reported after both procedures. METHODS We performed radiographic evaluations at a mean of thirty-nine months following 114 total ankle replacements done with use of commonly used implants and at a mean of thirty-seven months following forty-seven ankle arthrodeses. The mean age was sixty-four years for the patients (fifty-one female and sixty-three male) who underwent total ankle replacement and fifty-nine years in the patients (fifteen female and thirty-two male) who underwent ankle arthrodesis. The impact of complications was analyzed with use of the Ankle Osteoarthritis Scale (AOS), a validated outcome instrument. RESULTS Both groups had significant improvement in the mean AOS score (p < 0.001). There was no significant difference in the mean improvement between the two groups (p = 0.96). The complication rate was 54% following total ankle replacement and 26% following ankle arthrodesis, which was a significant difference (p = 0.003). The impact of major complications on the AOS outcome score was significant in both the total ankle replacement group (p = 0.031) and the ankle arthrodesis group (p = 0.02). CONCLUSIONS At the time of follow-up, at a minimum of two years postoperatively, the outcomes of total ankle replacement and ankle arthrodesis, with regard to pain relief and function, were comparable. While the rate of complications was significantly higher following total ankle replacement, the impact of complications on outcome was clinically relevant in both groups.

Arthroscopic Versus Open Ankle Arthrodesis: A Multicenter Comparative Case Series

BACKGROUND Ankle arthrodesis results in measurable improvements in terms of pain and function in patients with end-stage ankle arthritis. Arthroscopic ankle arthrodesis has gained increasing popularity, with reports of shorter hospital stays, shorter time to solid fusion, and equivalent union rates when compared with open arthrodesis. However, there remains a lack of high-quality prospective data. METHODS We evaluated the results of open and arthroscopic ankle arthrodesis in a comparative case series of patients who were managed at two institutions and followed for two years. The primary outcome was the Ankle Osteoarthritis Scale score, and secondary outcomes included the Short Form-36 physical and mental component scores, the length of hospital stay, and radiographic alignment. There were thirty patients in each group. RESULTS Both groups showed significant improvement in the Ankle Osteoarthritis Scale score and the Short Form-36 physical component score at one and two years. There was significantly greater improvement in the Ankle Osteoarthritis Scale score at one year and two years and shorter hospital stay in the arthroscopic arthrodesis group. Complications, surgical time, and radiographic alignment were similar between the two groups. CONCLUSIONS Open and arthroscopic ankle arthrodesis were associated with significant improvement in terms of pain and function as measured with the Ankle Osteoarthritis Scale score. Arthroscopic arthrodesis resulted in a shorter hospital stay and showed better outcomes at one and two years.

Preference-Based Quality of Life of End-Stage Ankle Arthritis Treated with Arthroplasty or Arthrodesis

Background: Health state values, or “utilities,” are an important preference-based measure of quality of life used by health economists. This study describes the utilities reported by a multicenter cohort of subjects with end-stage ankle arthritis treated with ankle arthrodesis or total ankle arthroplasty. Materials and Methods: Subjects with end-stage ankle arthritis were enrolled in a multicenter prospective cohort study. All subjects received either ankle arthrodesis or total ankle arthroplasty. Participants completed baseline SF-36 outcome evaluations preoperatively and at 1-year followup. Preference-based quality of life was assessed using health state values (HSVs) derived from the SF-36 (SF-6D transformation). Results: 107 subjects were included. The mean baseline SF-6D health state value for the TAA group was 0.67 (95% CI 0.64 to 0.69) and 0.66 (95% CI 0.63 to 0.68) for the arthrodesis group. At 1-year followup, the mean reported health state value was 0.73 (95% CI 0.71 to 0.76) for the total ankle arthroplasty group and 0.73 (95% CI 0.70 to 0.76) for the ankle arthrodesis group. The 1-year followup results approach age- and gender-matched US population norms. Health state values poorly correlated with age, however, significant differences between genders were detected. Conclusion: These data demonstrate an improvement in preference-based quality of life following ankle arthroplasty or arthrodesis. The results also provide necessary data that can be used in future cost-effectiveness analyses. Level of Evidence: II, Prospective Comparative Study

Tibial Nerve Palsy Associated with Lateralizing Calcaneal Osteotomy: Case Reviews and Technical Tip:

Level of Evidence: V, Expert Opinion

Factors Associated with Longer Length of Hospital Stay After Primary Elective Ankle Surgery for End-Stage Ankle Arthritis

BACKGROUND Longer length of stay in the hospital after elective surgery results in increased use of health-care resources and higher costs. Improved perioperative care permits many foot and ankle surgical procedures to be performed as day surgery. This study determined perioperative factors associated with a longer length of stay after elective total ankle replacement or ankle arthrodesis. METHODS Data were prospectively collected on patients who underwent open or arthroscopic ankle fusion or total ankle replacement for end-stage ankle arthritis at our institution from 2003 to 2010. Univariate and multivariable generalized linear regression models with gamma distribution and log link function were conducted with use of the length of the hospital stay as the dependent variable and preselected risk factors of age, sex, physical and mental functional scores, comorbid factors, American Society of Anesthesiologists grade, body mass index, type of surgery, duration of surgery, and surgery day of the week as the independent variables. RESULTS This study included 343 patients with a median length of stay of seventy-five hours (interquartile range, fifty-two to ninety-seven hours). With use of regression analyses, the variables of age, female sex, higher American Society of Anesthesiologists grade, multiple medical comorbidities, rheumatoid arthritis, lower Short Form-36 Physical Component Summary and General Health domain scores, and open surgery were significantly associated with increased length of stay. Conversely, the variables of obesity, Short Form-36 Mental Component Summary score, surgery day of the week, and surgical duration were not associated with length of stay. Two predictive models of the length of stay were developed: one included only patient-related factors, and the other included patient and surgery-related factors. CONCLUSIONS The patients who are identified with a higher risk of a longer length of stay may warrant better education and more focused perioperative care when designing care pathways and allocating health-care resources.