Peter Dryden

Radiographic Assessment of Adult Flatfoot

Background: The accurate measurement of flatfoot on standing radiographs allows correct diagnosis of the condition and evaluation of reconstructive procedures. Method: The standing radiographic measurements of patients with symptomatic, adult flatfoot were compared to controls using blinded observers.Results: On the lateral radiograph, the talar-to-first metatarsal angle, the calcaneal pitch angle, and the medial cuneiform-fifth metatarsal height differed significantly between the patient group and the controls. The difference in the talar-to-first metatarsal angles on lateral radiographs was the most statistically significant (patient group 21.1 ±10.8 degrees and control 7.1 ± 10.7 degrees, p < 0.0001) with good correlation between readings (intraobserver 0.75, interobserver 0.83). On the anteroposterior (AP) radiograph, the talar head uncoverage distance was the most significantly different measurement between these groups. Conclusions: These findings support the hypothesis that the talar-first metatarsal angle is an accurate radiographic identifier of patients with symptomatic, adult flatfoot.

Immunologic studies of the mechanisms of occupational asthma caused by western red cedar

BACKGROUND Occupational asthma caused by western red cedar (Thuja plicata) is a common problem in sawmill industries. The objective of this study was to examine the cellular and immunologic mechanisms of western red cedar asthma (WRCA) more closely. METHODS Bronchial biopsy specimens, bronchoalveolar lavage (BAL) mast cells and peripheral blood basophils from patients with WRCA, patients with atopic asthma, and nonatopic control subjects were challenged in vitro with plicatic acid (PA), PA-human serum albumin conjugate (PA-HSA), grass pollen, or calcium ionophore. RESULTS PA (100 micrograms/ml) released histamine from the basophils of 9 of 11 patients with WRCA, 1 of 7 patients with atopic asthma, and 2 of 7 normal subjects. PA triggered histamine release from 10 of 11 bronchial biopsy specimens and 8 of 8 BAL samples from patients with WRCA. Interestingly, PA released histamine from BAL cells and bronchial biopsy specimens from 3 of 7 normal subjects but in none of the patients with atopic asthma. PA-HSA-induced histamine release from basophils and biopsy specimens was confined to patients with WRCA. PA-specific IgE was not detectable in serum from most patients with WRCA, and their serum did not transfer PA sensitivity to human lung fragments or lactate-stripped basophils. After pretreatment with anti-IgE in the absence of calcium, basophils from 14 subjects with WRCA still responded to PA (mean 64% to 67% of pretreatment response), whereas responses to grass pollen or anti-IgE were abolished. CONCLUSIONS This study confirms that PA releases histamine from bronchial mast cells of most patients with WRCA but not from those of patients with atopic asthma. The PA response of some normal subjects suggests that PA may have both specific and nonspecific actions on mast cells and basophils, whereas the serologic studies indicate histamine release in WRCA cannot simply be attributed to PA-specific IgE.

Outcome of Total Ankle Arthroplasty in Patients with Rheumatoid Arthritis and Noninflammatory Arthritis A Multicenter Cohort Study Comparing Clinical Outcome and Safety

BACKGROUND Patients with rheumatoid arthritis often have degeneration of the ankle and ipsilateral hindfoot joints. Patients with rheumatoid arthritis undergoing total ankle arthroplasty have a higher risk of wound breakdown and infection. We compared intermediate-term clinical outcomes after total ankle arthroplasty in patients with rheumatoid arthritis and patients with noninflammatory arthritis. METHODS Fifty patients with rheumatoid arthritis were compared with fifty patients with noninflammatory arthritis (the control group), matched for age within ten years, prosthesis type, and follow-up time. All patients underwent total ankle arthroplasty. Revisions and major complications were noted. Outcome scores included the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) Health Survey. RESULTS The groups were similar with respect to body mass index and length of follow-up (mean, 63.8 months for the rheumatoid arthritis group and 65.6 months for noninflammatory arthritis group); the rheumatoid arthritis group was younger (mean, 58.5 years compared with 61.2 years). The mean AOS pain scores were significantly different in the rheumatoid arthritis and noninflammatory arthritis groups preoperatively (p < 0.01), but were similar following total ankle arthroplasty (mean and standard deviation, 18.5 ± 17.8 for the rheumatoid arthritis group and 19.7 ± 16.5 for the noninflammatory arthritis group; p = 0.93). Both groups showed significant improvement (p < 0.05) with regard to the AOS scores for pain and disability and SF-36 physical component summary scores following surgery. Postoperatively, AOS disability and SF-36 physical component summary scores were better for patients with noninflammatory arthritis. There were seven revisions in the rheumatoid arthritis group and five in noninflammatory arthritis group. There was one major wound complication in the rheumatoid arthritis cohort and none in the control cohort. CONCLUSIONS Patients with rheumatoid arthritis benefit from total ankle arthroplasty and have similar outcomes to patients with noninflammatory arthritis. The overall pain and disability were worse for patients with rheumatoid arthritis than for those with noninflammatory arthritis preoperatively, but this did not negatively influence their final outcomes. When properly treated, patients with rheumatoid arthritis achieve good results.

Inhibition of human neutrophil responses by α-cyano-3,4-dihydroxythiocinnamamide; a protein-tyrosine kinase inhibitor

1 Activation of neutrophils results in increased tyrosine phosphorylation of several proteins that may have important roles in receptor/effector coupling. In this study, the effect of a protein tyrosine kinase inhibitor on receptor‐mediated neutrophil activation by platelet‐activating factor (PAF), leukotriene, B4 (LTB4) and N‐formylmethionylleucylphenylalanine (FMLP) is investigated. 2 α‐Cyano‐3,4‐dihydroxythiocinnamamide dose‐dependently inhibited intracellular calcium release and superoxide generation from human neutrophils activated by 1 μm LTB4, PAF, and FMLP. 3 In the presence of cytochalasin B, FMLP stimulated elastase release from neutrophils was also inhibited to unstimulated levels by 5 min pretreatment with α‐cyano,3,4‐dihydroxythiocinnamamide. 4 The inhibitory action of α‐cyano‐3,4‐dihydroxythiocinnamamide was found to be at or upstream of phospholipase C activation, blocking both phosphatidylinositol hydrolysis and protein kinase C activation. α‐Cyano‐3,4‐dihydroxythiocinnamamide did not affect agonist receptor binding sites or receptor affinity in neutrophils. 5 Immunoblot analysis demonstrated the tyrosine phosphorylation of proteins of 41, 56, 66, and 104 kDa in neutrophils treated with agonists. Treatment of neutrophils with α‐cyano‐3,4‐dihydroxythiocinnamamide prior to stimulation with chemoattractants reduced tyrosine phosphorylation of the above phosphoproteins. 6 These results indicate that α‐cyano‐3,4‐dihydroxythiocinnamamide might be a useful agent in characterizing the essential proteins and biochemical pathways that regulate neutrophil activation.

Involvement of immunologic mechanisms in a guinea pig model of Western red cedar asthma

Western red cedar asthma is the most common form of occupational asthma in the Pacific Northwest. Plicatic acid (PA) is the chemical component of Western red cedar that causes asthma. The role of immunologic processes involved in the PA-induced asthmatic reaction has not been established. To characterize the mechanisms of PA-induced asthmatic reaction, guinea pigs were sensitized to PA through biweekly injection of PA-ovalbumin conjugate with aluminum hydroxide as an adjuvant for a period of 6 months. Specific IgG1 antibodies to PA were detected in the blood 3 months after sensitization of animals. The level of specific IgG1 antibodies to ovalbumin after 6 months was about two times the level of specific IgG1 to PA. At 6 months, tracheal tissue from PA-ovalbumin-sensitized guinea pigs contracted after exposure to either PA or ovalbumin in vitro. The degree of contraction induced by PA was two to three times less than the contraction induced by ovalbumin. PA caused histamine, prostaglandin D2, and leukotriene D4 release from both lung mast cells and blood basophils. The amount of histamine and eicosanoids released by PA was also two to three times less than the amount of mediators released by ovalbumin. When the trachea of normal guinea pigs was passively sensitized with serum from PA-ovalbumin-sensitized guinea pigs, it contracted in response to PA or ovalbumin in an organ bath. When the serum of PA-ovalbumin-sensitized guinea pigs was depleted of immunoglobulins and then used for passive sensitization of normal trachea, no contraction was observed when challenged with PA, suggesting that IgG1 antibodies mediate the tracheal reaction to PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Is the Canadian Orthopaedic Foot and Ankle Society Ankle Arthritis Score (COFAS AAS) Associated with the Need for Revision Surgery

Category: Ankle Arthritis Introduction/Purpose: There has been limited evidence to support the effective use of a patient reported outcome measure (PROM) for patients that have undergone surgical treatment for end-stage ankle arthritis (ESAA). This study used longitudinally collected patient-data from a cohort of patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) ankle arthritis study to evaluate whether the post-operative COFAS Ankle Arthritis Score (COFAS AAS), a patient-reported outcome (PROs), was associated with need for revision surgery. Methods: Between 2001 and 2010, a cohort of 623 patients and 653 ankles undergoing total ankle replacement or ankle arthrodesis were enrolled in a multicenter prospective ankle reconstruction study. At pre-surgical baseline, key patient level variables were collected including demographics, body mass index, and comorbidities. The COFAS AAS, a patient-reported outcome measure was collected at baseline and annually post-surgically. Time to revision surgery was modeled using a proportional hazards model which controlled for age, sex, BMI, diabetic status, smoking status, inflammatory arthritis, and surgery on the right or left side and time varying PROs. Results: 531 ankles in 509 patients with complete pre and post-operative data were included. Seventy of the cohort underwent metal component revision procedures during the follow up time period . The remaining 461 unrevised ankles had a minimum 2 year follow up (average of 3.4 years). Baseline COFAS AAS, age, sex, side, BMI, diabetic status, smoking status, and inflammatory arthritis were not statistically associated with the need for revision surgery. However, revision surgery was found to be associated with a higher post-operative COFAS AAS, and with a longer follow-up. The hazard ratio for the COFAS AAS indicates that for every one-point increase in the score, the rate of revision surgery was one percentage point higher at each post-operative time point. Conclusion: This study demonstrated that patients who reported higher levels of post-operative functional impairment, as indicated by a higher COFAS AAS, were more likely to undergo a revision surgery. This finding is also based on duration of follow-up, with the risk of revision surgery rising with length of follow up. This study provides further evidence for the utility of the COFAS AAS in the clinical setting. Further investigation is warranted to better understand the COFAS AAS’s ability to measure clinically meaningful change in an individual patient not requiring revision surgery.

Does Smoking Affect Outcome in Surgical Management of Ankle Arthritis? A COFAS Multicentre Study

Category: Ankle Arthritis Introduction/Purpose: Smoking has been shown to increase complication rates after ankle surgery. The aim of this study was to compare complication rates between smokers and non smokers undergoing surgery for ankle arthritis. Methods: Smokers (n=88) and non smokers (n=565) with ankle arthritis who had undergone ankle arthrodesis or ankle arthroplasty were included in the study. Multicentre, prospective data was used from the COFAS ankle arthritis database. Patients with information available on smoking habits and 2 year follow up were included Results: There was no significant difference in the overall re operation rates between smokers and non smokers. However, the amputation rate was higher in smokers (3.4%) as compared to non smokers (0.7%). AOS scores and SF 36 scores were similar in the 2 groups. A higher proportion of smokers underwent fusion (46.5%) as compared to non smokers (28.8%). Amputation rate after ankle arthrodesis was higher in smokers (4.9%) as compared to non smokers (0.6%). Conclusion: Smokers have a higher amputation rate after ankle arthrodesis or ankle arthroplasty as compared to non smokers. Information from this study can be used during counselling of surgical patients

Validity of a Revision Surgery Classification System for Ankle Arthritis Surgery

Category: Ankle Arthritis Introduction/Purpose: Reoperations may be a better way of tracking adverse outcomes than complications. Repeat surgery causes cost to the system, and often indicate failure of the primary procedure resulting in the patient not achieving the expected improvement in pain and function. Understanding the cause of repeat surgery at the primary site may result in design improvements to implants or improvements to fusion techniques resulting in better outcomes in the future. Repeat operations around the primary site may also be relevant to the primary surgery. The COFAS group have designed a reoperation classification system. The purpose of this study was to outline the inter and intra observer reliability of this classification scheme. Methods: To verify the inter- and intra-observer reliability of this new coding system, six fellow ship trained practicing foot and ankle Orthopaedic surgeons were asked to classify 61 repeat surgeries. The six surgeons read the operation reports in random order, and reread the reports 2 weeks later in a different order. Reliability was determined using regression analysis and intraclass correlation coefficients (ICC) were calculated and proportions of agreement. The agreement between pairs of readings (915 for inter observer for the first and second read; 61 readings with 15 comparisons) was determined by seeing how often each observer agreed. This was repeated for the 366 ratings for intra observer readings (61 times 6). Results: The inter-observer reliability test on the first read had a mean intra-class correlation coefficient (ICC) of 0.89, range 0.80 to 0.96. For 61 cases, 45 (74%) observations that were given the same code across all six observers for the first read. The inter-observer reliability test on the second read had a mean ICC of 0.94, range .90 to to 1.0. There were 43 (72%) observations that were the same across all six observers. Of all pairs (915 in total) there was agreement in 804 pairs for the first reading (88%). For the second reading there was agreement in 801 pairs (86%). The observers agreed with themselves in the intra-observer observation 324 times out of 366 paired readings (89% agreement of pairs). Conclusion: The COFAS classification of reoperations for end stage ankle arthritis was reliable. This scheme potentially could be applied to other areas of Orthopaedic surgery and should replace the Claiden Dindo modifications that do not accurately reflect Orthopaedic outcomes. As complications are hard to define and lack consistent terminology (Mercer) reoperations and resource utilization (extra clinic visits, extra days in hospital and extra hours of surgery may be more reliable measures of the negative effects of surgery.

Swelling Results in Poor Outcome After Ankle Arthritis Surgery

Category: Ankle Arthritis Introduction/Purpose: Patients often comment on swelling after foot and ankle surgery. However the relationship between swelling and outcome has not been defined. Pinsker and Daniels demonstrated that swelling was an important aspect of outcome. The purpose of this paper was to determine the relationship between swelling score and outcome after ankle fusion and replacement. A secondary purpose was to determine how this relationship changed in time, how swelling score changed before and after surgery, and determine differences in swelling score between total ankle replacement (TAR), open ankle arthrodesis (OAA) and arthroscopic ankle arthrodesis (AAA). Methods: The MODEMS outcomes package from AAOS was used, with the validated ankle osteoarthritis score (AOS) score being used to assess outcomes in the pain and disability domains. The swelling score was indexed from 1 to 5, 1 being no swelling and five being severe swelling. Outcomes were recorded pre-operatively and annually up to 2010. Statistical analysis was performed using 95% confidence intervals and correlations being determined using Pearson’s correlation and r 2 values. Results: The swelling score was correlated with AOS score preoperatively. Postoperatively patients with a swelling score of 1 had an average AOS score of 15.1 (CI 13.3 to 16.9), a swelling score of 2 had an AOS score of 23 (CI 21.7 to 24.9), 3 an AOS of 31 (CI 29.6 to 33.1), 4 an AOS of 33.6 (CI 34.9 to 38.8), and 5 an AOS of 39 (CI 35.3 to 43.0). There was therefore a difference in outcome score for all groups of swelling score (i.e. 1 scored better than 2, 2 better than 3, 3 better than 4 and 4 better than 5). Swelling scores were the same for TAR, OAA and AAA preoperatively. Postoperatively swelling scores were lower for AAA (2.1, CI 1.9 to 2.2) compared to TAA (2.5, CI 2.4 to 2.6) and OAA (2.5, CI 2.4 t0 2.6). Conclusion: Swelling has a relationship with outcome. Swelling after surgery may result in poorer outcomes. Strategies to reduce swelling such as patient education about elevation, surgical technique and the use of compression stockings may improve outcomes. Arthroscopic surgery may have better outcomes because of the reduction in postoperative swelling.