Use of Navigation-Enhanced Instrumentation to Mitigate Surgical Outliers During Total Knee Arthroplasty.

Computer-assisted orthopedic surgery improves mechanical alignment and the accuracy of surgical cuts in the context of total knee arthroplasty (TKA). A simplified, navigation-enhanced instrumentation system was assessed to determine whether the same effects could be achieved with a less intrusive system. Two cohorts of surgeons (experienced and trainees) performed a series of TKA cuts using models with and without navigation-enhanced instrumentation. The accuracy of each system was determined via the rate of outliers, measured as any cut that deviated from the planned cut by more than 2° or 2 mm. The effect of experience level was limited, with only the outlier rate for tibial varus or valgus measurement showing a significant difference between user groups with conventional instrumentation (P=.004). The use of navigation-enhanced instrumentation significantly reduced the total outlier rate compared with conventional instrumentation from 35% to 4% for experienced users (P<.001) and from 34% to 10% for trainees (P<.001). These results suggest that navigation-enhanced instrumentation is a viable alternative to conventional instrumentation to reduce outlier rates and improve cut accuracy. This trial also showed that additional experience may not correlate with improved surgical accuracy. Outliers may not reflect individual surgical ability as much as limitations of the instrumentation or other unidentified factors. [Orthopedics. 2021;44(1):54-57.].

The Effects of Pelvic Incidence in the Functional Anatomy of the Hip Joint.

BACKGROUND: The spine-pelvis-hip interaction during postural change should be considered in the functional anatomy of the hip. The component parts of this anatomy and how they influence hip function are important to know. Pelvic incidence (PI) is one of these components. We studied if PI was preoperatively predictive of impingement risk and if it postoperatively influences hip position, which could cause outliers from the functional safe zone of hip replacement. METHODS: This was a prospective radiographic study of 187 consecutive patients (200 hips) who had lateral spinopelvis-hip radiographs before and after primary total hip arthroplasty with measurements of the component factors that influence mobility and position of the functional anatomy. The predictive value of PI for risk of impingement of the hip and its postoperative relationship to functional safe-zone outliers were assessed. Forty-one dislocations from our clinical practice were also reviewed. RESULTS: Of 200 hips, the PI was normal in 145 hips (73%), low in 18 hips (9%), and high in 37 hips (19%). Eighty-two hips had spinopelvic imbalance: 12 (67%) of the 18 hips with low PI, 56 (39%) of the 145 hips with normal PI, and 14 (38%) of the 37 hips with high PI. Low-PI hips was the most predictive of the risk of impingement and postoperatively these hips had the most outliers from the functional safe zone. CONCLUSIONS: PI is an anatomical component that is predictive of both impingement risk and functional safe-zone outliers. Preoperative risk, based on factors such as the Lewinnek zones and combined anteversion, is an established guide in determining cup position in hip replacement. Low-PI hips that have the "terrible triad" of a posteriorly tilted pelvis, stiff pelvic mobility, and increased femoral flexion therefore have no functional safe zone. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Improved Range of Motion and Patient-Reported Outcome Scores With Fixed-Bearing Revision Total Knee Arthroplasty for Suboptimal Axial Implant Rotation.

BACKGROUND: Suboptimal implant rotation has consequences with respect to knee kinematics and clinical outcomes. We evaluated the functional outcomes of revision total knee arthroplasty (TKA) for poor axial implant rotation. METHODS: We retrospectively reviewed 42 TKAs undergoing aseptic revision for poor axial implant rotation. We assessed improvements in Knee Society Score (KSS) and final range of motion (ROM). Subgroup analyses were performed for preoperative instability and stiffness, as well as the number of components revised and level of implant constraint used. RESULTS: Revision for poor axial rotation in isolation improved KSS from 52 ± 22 to 84 ± 25 (P < .001), and flexion increased from 105 ± 21° to 115 ± 13° (P = .001). Revision in the setting of instability significantly improved the KSS (P < .001) but did not affect ROM (P = .172). Revision in the setting of stiffness significantly improved both KSS (P < .001) and ROM (P = .002). There was no statistically significant difference between the postoperative KSS (P = .889) and final knee flexion (P = .629) with single- or both-component revision TKA for isolated poor axial rotation or between the postoperative KSS (P = .956) and final knee flexion (P = .541) with or without the use of higher constraint during revision TKA for isolated poor axial rotation. CONCLUSION: Revision TKA for poor axial alignment improves clinical outcomes scores and functional ROM.

Blinded Clinical Evaluation of a New Toothbrush Design.

OBJECTIVE: The purpose of this single-blind, crossover study was to compare plaque removal associated with a new manual toothbrush, the O'Nano and a best-selling, commercially available manual toothbrush, the Oral-B Indicator 40. The O'Nano toothbrush has a patented "one-piece molded design" made of Thermal Plastic Urethane, a plastic that has been used in medical devices. METHODOLOGY: Over a six-week period, 40 subjects participated. Following random assignment, 22 subjects started with the O'Nano brush and the remaining started with the Oral-B Indicator 40 brush. Crossover occurred after two-weeks' use of each brush (two-week washout in between). Plaque was scored before and after brushing using the Turesky modification of the Quigley-Hein Index (T/Q-H). Plaque accumulation was 12 to 18 hours prior to examination and brushing. RESULTS: Thirty-nine subjects completed the study; one subject was dropped for non-compliance. Groups were virtually identical at the onset in plaque level scores by study design. In comparison to baseline, both brushes achieved significant (p < 0.001) plaque reductions (gains) with a matched-paired comparison t-test. The O'Nano brush gain was 0.445 (18%) per subject and the Oral-B Indicator 40 brush was 0.504 (20%) per subject. The difference in plaque removal capability between brushes averaged 0.60 in favor of the Oral-B Indicator 40 brush, a non-significant (p = 0.20) finding determined by a matched-paired comparison t-test, which is identical to the repeated measures ANOVA when there are two groups and two time periods. Standard deviation (SD) was smaller for the O'Nano brush in plaque reduction scores (0.183 < 0.235). This difference was tested and found to be non-significant with this particular group size. CONCLUSION: Statistical analysis of T/Q-H scores demonstrated that the O'Nano brush is comparable to the Oral-B Indicator 40 brush under the conditions of this study protocol. With this small study group the slight differences in plaque removal efficiency between both brushes was not significant. The unique "one-piece molded" design of the O'Nano brush was not evaluated for durability in comparison to a more conventional brush, the Oral-B 40.

The effectiveness of scaling and root planing with adjunctive time-release minocycline using an open and closed approach for the treatment of periodontitis.

The purpose of this study was to determine the effectiveness of scaling and root planing using a closed and open approach (papilla reflection) with and without a locally delivered antibiotic (minocycline hydrochloride microspheres) in the treatment of moderate to advanced chronic periodontitis. Twenty-five periodontal recall patients with four or more probing depths of 5.0 to 9.0 mm and bleeding on probing (BOP) participated in this double-blind trial. Each of four sites per patient was randomly assigned a different treatment: scaling/root planing only; scaling/root planing followed by minocycline placement; gingival papilla reflection followed by scaling/root planing and flap closure; and gingival papilla reflection, scaling/root planing, minocycline placement, and flap closure. At baseline and each subsequent appointment, probing depth, BOP, and clinical crown length were recorded. Patients returned at three months for measurements and supportive periodontal therapy, and at six months for final measurements. Patients followed their usual oral hygiene regimens. Data were analyzed for significant differences using a repeated measure ANOVA and a Student t-test. All treatments resulted in reduction of probing depths (average of 1.76 mm) and a marked reduction in BOP at six months. While the papilla reflection plus minocycline showed the greatest reduction in probing depth (1.91 mm) and the greatest decrease in BOP (20% at three months and 28% at six months), the differences were not significant (p > 0.05). Clinical crown lengths did not change significantly in the treatment sites; therefore, improvements in probing depth can be attributed to improved clinical attachment levels (long junctional epithelium). The combination therapies did not differ significantly from scaling/root planing alone in decreasing probing depths and BOP.

Effectiveness of root planing with diode laser curettage for the treatment of periodontitis.

This study investigated the effectiveness of scaling/root planing using closed approach, closed approach with laser-curettage, closed approach with laser-curettage/laser-sealing, and an open approach (papilla reflection/flap closure) in treating moderate-advanced chronic periodontitis. All treatments resulted in a reduction in probing depth and bleeding upon probing. The closed approach therapies: SRP, laser-curettage/SRP, and laser-curettage/SRP/laser-sealing resulted in less gingival recession than the open approach (papilla reflection/flap closure). If esthetics are a concern, laser-curettage is a viable option.

Effects of nutritional supplementation on periodontal parameters, carotenoid antioxidant levels, and serum C-reactive protein.

Few studies have focused on the role of nutrition in periodontal disease. The purpose of this trial was to determine the effect of a nutritional supplement on gingival inflammation, bleeding, probing depth, clinical attachment level, carotenoid antioxidant level, and C-reactive protein. The test supplement, consisting of a standard multivitamin formula, as well as several phytonutrients associated with antiinflammatory/antioxidant effects, provided modest benefits in reducing inflammation; however, further studies with larger populations and longer intervention are warranted.

An investigation of dentists' and dental students' estimates of diagnostic probabilities.

BACKGROUND: Research in medicine has shown that physicians have difficulty estimating the probability that a patient has a condition on the basis of available diagnostic evidence. They consistently undervalue baseline information about the patient relative to test information and are poor intuitive calculators of probability. The authors could not locate in the literature any studies of diagnostic probability estimates from baseline information and test data for dentists. METHODS: Using two vignettes that contained different baseline information, dental students and clinical faculty members estimated the probability that the described hypothetical patient had the condition in question. Respondents also commented on the project. CONCLUSIONS: Both groups of respondents overemphasized the importance of test evidence relative to baseline information, although experienced practitioners did so to a lesser extent than did students. Respondents, especially practitioners, expressed resistance to performing a diagnostic task that required precise estimates of probability. CLINICAL IMPLICATIONS: Dentists appear to estimate diagnostic probabilities in an intuitive fashion, but they do so imprecisely. Clinical experience provides some protection against the bias of overestimating test evidence compared with baseline information. These findings raise questions about how practitioners use probability estimates and whether other models also may play a role. The incorporation of information from evidence-based dentistry into practice requires better understanding.

Cement technique changes improved hip resurfacing longevity - implant retrieval findings.

BACKGROUND: Most designs of metal-on-metal hip resurfacing utilize cement for femoral fixation, but the amount, application, and distribution of cement varies considerably according to implant design and surgeon preference. In one type of hip resurfacing system (Conserve Plus), the objective was to achieve a 1-mm cement mantle and several millimeters of penetration. In early cases of the senior investigator's (HCA) series, cement fixation failures were noted, and this prompted changes in femoral head preparation and cement application techniques. Survivorship improved following implementation of these changes. The aim of the current study was to examine revised femoral components for the cement distribution, especially in cases where the improved techniques were subsequently applied. METHOD: Fifteen resurfacing femoral components were sectioned and the slices were radiographed and photographed, and the amount and distribution of cement were examined and measured. Cases representative of the evolving cementing techniques were examined in detail. RESULTS: There was considerable variation observed in the amount and distribution of cement, partly as a consequence of variable bone quality in this "all-comers" included series. The cement analyses showed that the newer cementing techniques helped to reduce over-penetration while providing better cement interdigitation. The use of extra fixation holes and cementing the stem in cases with poor bone quality were associated with improved cement-to-bone contact area. CONCLUSION: Meticulous femoral head preparation was helpful in providing durable cement fixation and is essential in cases with poor bone quality.

Tweezer dexterity aptitude of dental students.

The rationale for using the Perceptual Ability Test (PAT) as a component in admissions decisions for dental schools is that candidates vary in an underlying aptitude that is predictive of degree of success in technique course performance and perhaps in clinical performance. There have been periodic attempts to identify tests that more directly measure manual dexterity aptitude that would supplement the predictive power of admissions decisions. Previous research has demonstrated that a commercially available "speeded" tweezer dexterity test (Johnson O'Connor Test #32022) is not associated with performance in dental school or dental practice. Our research investigated both Test #32022 and Test #18 that measure both speed and accuracy as potential predictors of dental school performance in technical and clinical courses. This article reports the results of a longitudinal, comparative study of tweezer dexterity scores for students at the University of the Pacific School of Dentistry during their first and last quarters in school. The goals of the study were to 1) evaluate the correlation between beginning students' scores on two different types of tweezer dexterity tests; 2) compare dental students' scores to normative data for the general population; 3) determine the effect of a dental curriculum on students' performance on Test #18; and 4) evaluate the two tests as potential dental school admission screening instruments in comparison to the PAT. Fifty first-quarter students were tested from a class of 134. Forty-nine of these students were retested on Test #18 during their final quarter. The predictor value of the initial scores for the two dexterity tests was assessed for seven outcome measures reflecting student technique performance. Analysis showed a significant correlation (r=0.318, p<0.05) between the two dexterity tests. The difference between the norm mean (41.58) and the dental student mean for Test #18 (40.42) was not significant (p>0.05). The correlation between the first and final quarter administrations for Test #18 was r=0.517 (p<0.01). The predictive power of these tests for the seven educational outcomes measures was weak. Results suggest that dental student tweezer dexterity is no different from that of the general population and is not changed by completing a dental school curriculum. The ability for an applicant to perform successfully in dental school will not be reliably predicted by tweezer dexterity score.

Longitudinal evaluation of prostaglandin E2 (PGE2) and periodontal status in HIV+ patients.

The study aim was to determine whether prostaglandin E(2) (PGE(2)) in gingival crevicular fluid (GCF) could serve as a risk factor for periodontitis in human immunodeficiency virus-positive (HIV(+)) patients. Clinical measurements, including gingival index (GI), plaque index, bleeding index, probing depth (PD), attachment loss (AL) and GCF samples were taken from two healthy sites (including sites with gingival recession, GI=0; PD< or =3 mm; AL< or =2 mm), three gingivitis sites (GI>0; PD< or =3 mm; AL=0) and three periodontitis sites (GI>0; PD> or =5 mm; AL> or =3 mm) of each of the 30 patients at baseline and 6-month visits. GCF samples were also taken by means of paper strips. GCF PGE(2) levels were determined by a sandwich ELISA. The progressing site was defined as a site which had 2 mm or more attachment loss during the 6-month study period. The mean amounts of PGE(2) were significantly higher in gingivitis and periodontitis sites than in healthy sites (p<0.0001). GCF levels of PGE(2) were significantly correlated with probing depth, attachment loss, CD4(+) cells, viral load, age and smoking pack-years at baseline and 6-month visits (0.0001

Research on hand dexterity and the practice of dentistry: reality and myth.

A brief review of the literature finds that studies of digital dexterity fail to confirm that dental students or dentists possess aptitudes that are different from the general population or that those with higher aptitudes achieve superior levels of performance. It is suggested that the complex nature of modern dental practice requires such a broad range of skills that digital dexterity contributes only a small increment or that technical dental procedures are completely trainable in the course of dental education.

Blinded clinical evaluation of a new manual toothbrush.

OBJECTIVE: A new manual toothbrush with an innovative design has recently been introduced into the marketplace. The purpose of this single-blind, crossover study was to compare plaque removal associated with this new manual toothbrush (Curvex) and a best-selling commercially available manual tootbrush (Oral-B Indicator 40). METHODOLOGY: Over a five-week period, twenty-one subjects participated in this investigation. Following random assignment, ten of the subjects started with the Curvex toothbrush, and the remaining subjects began with the Oral-B Indicator 40 toothbrush. Subjects brushed twice daily for two minutes over a two-week period. After a one-week washout period, the subjects brushed with the alternate toothbrush for two weeks. At the beginning and end of each two-week trial period, subjects were scored before and after brushing using the Turesky modification of the Quigley-Hein Plaque Index (T/Q-H). Findings of reductions in plaque scores were limited to "before vs. after" assessments. Plaque scores were measured in each subject (up to 168 sites) on each of four occasions. RESULTS: The average baseline and test plaque scores for the Oral-B Indicator 40 brush were 2.41 and 1.72; for the Curvex brush these values were 2.34 and 1.69. Repeated measures ANOVA revealed no difference between brushes. Paired-comparison t-tests were conducted on each of the 168 evaluated sites, and no patterns of superiority for either brush were identified. Although both toothbrushes effectively reduced mean plaque scores, ANOVA demonstrated no significant difference between toothbrushes. CONCLUSION: The Curvex toothbrush is as effective as the Oral-B Indicator 40 toothbrush in removing plaque. Additionally, there was no evidence of any soft tissue abrasion from either brush.