Methods for the estimation of nisin in solution and in foods are described and the nisin unit is redefined. The presence of interfering substances in certain food extracts has been demonstrated. In the foods examined compensation for the effect on the plate assay could be made by inactivating the nisin by an alkali treatment, and using these treated extracts as a basis for controls. For quantitative determination of suspensions of nisin alone and in food extracts, a large plate diffusion method requiring no prediffusion and using M. flavus as test organism is described. For semi‐quantitative estimations, or for sorting purposes, a simple reverse‐phase disk assay technique based on B. stearothermophilus spores, with overnight incubation at 55°, is proposed.

1. Certain starter cultures have been found to be inhibited in the presence of milk peroxidase.2. A high correlation has been established between the inactivation of milk peroxidase and of the inhibitory action by use of critical values of any of the following: temperature, pH, concentration of either sodium azide or hydrogen peroxide.3. The inhibitory action can be overcome by the addition of certain reducing substances such as cysteine and sodium hydrosulphite.4. The inhibitory action is exhibited by the corresponding separated milk and whey.5. It is suggested that this inhibition may be due to the formation of a specific inhibitory oxidation product having a quinonoid structure.6. The addition of 1–2% of pasteurized milk or whey to autoclaved milk caused total inhibition, whereas such additions to milk heated to 190° F. showed no such effect. This is attributed to the presence of SH groups in the latter milk capable of reducing the oxidation product.7. It is suggested that the inhibition due to peroxidase is identical with that ascribed to lactenin 2, and that the inhibition described in our previous paper as due to ‘agglutinin’ is identical with that ascribed to lactenin 1.

Background: National Basketball Association (NBA) players who return to sport (RTS) after Achilles tendon rupture have been reported to have poor outcomes. Purpose: To evaluate the effect of Achilles tendon ruptures on player performance and career longevity in NBA athletes. Study Design: Cohort study; Level of evidence, 3. Methods: NBA players who sustained Achilles tendon ruptures between 1970 and 2019 were identified using publicly available resources and were matched 1:1 to a healthy control group by age, position, height, and body mass index. Demographic characteristics, player utilization (games and minutes), and performance efficiency rating (PER) were documented for all athletes. The season of Achilles tendon rupture was set as the index year, and statistical analysis compared postindex versus preindex data both acutely and in the long term. Percentages relative to preoperative values were calculated to compare the injured and control groups in a standardized fashion. Results: Of 47 players, 34 (72.3%) with Achilles tendon ruptures returned to play at the NBA level after surgical intervention. A total of 7 players were excluded from the study. No differences were found in demographic characteristics or PER (2 years before injury) between the remaining 27 players and matched controls. The injured players had significantly shorter careers compared with control players (3.1 ± 2.3 vs 5.8 ± 3.5 seasons, respectively; P < .05). Injured players demonstrated significant declines in games per season (GPS), minutes per game (MPG), and PER at 1 year and 3 years after RTS compared with preindex baseline ( P < .05). Injured players, compared with control players, had reduced relative percentages of games started (GS) (50% vs 125%, respectively), MPG (83% vs 103%), and PER (80% vs 96%) at 1 year after return ( P < .05), but reductions at extended 3-year follow-up were seen only in GPS (71% vs 91%) and GS (39% vs 99%) ( P < .05). Conclusion: Our study found that 72.3% of NBA players returned to play after Achilles tendon repair, but they had shorter careers compared with uninjured controls. Players returning from Achilles tendon repairs had decreased game utilization and performance at all time points relative to their individual preindex baseline. However, for the injured players when compared with controls, game utilization but not performance was found to be decreased at 3-year follow-up.

Ultrasonography (US) is an inexpensive, convenient, and effective tool that can be used to evaluate the shoulder. It does not expose the patient to harmful radiation and can be used to evaluate the musculoskeletal system dynamically. Additionally, US is not subject to metal artifacts when evaluating patients with previously placed hardware. Over the years, US has been found to be reliable and accurate for diagnosing rotator cuff tears (RCTs), despite its operator-dependence. The usage of US for diagnosing RCTs in orthopedic practice varies depending on practitioners’ familiarity with the exam and the availability of experienced technicians. The purpose of this article is to review the diagnostic accuracy of US for identifying RCTs.

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Background:A proposed mechanism for recurrent instability following anterior cruciate ligament (ACL) reconstruction is failure of the anterolateral ligament (ALL). Presently, there are a number of approaches to treating ALL pathology.Purpose:To determine practice patterns among orthopaedic surgeons regarding ALL during ACL reconstruction.Study Design:Cross-sectional study.Methods:An online 7-question survey was sent to all physicians registered with the American Orthopaedic Society for Sports Medicine between June and July 2017. Results were analyzed with the survey website.Results:Overall, 225 of 3467 surgeons responded to the survey, 86 of whom performed ALL reconstruction and completed each question in the survey. Eighty-six (38.2%) surgeons who responded to the questionnaire stated that they perform ALL reconstruction/lateral extra-articular tenodesis in conjunction with ACL reconstruction. The most common indications for ALL reconstruction were grade III pivot-shift test (46.0%) on physical examination and revision ACL reconstruction (46.0%). The most common technique used to perform ALL reconstruction was hamstring autograft (48.2%). The majority of participating surgeons (87.5%) stated that they do not make any alterations to their postoperative rehabilitation protocol after they perform ALL reconstruction. In addition, most surgeons responding to the survey (91.3%) anticipated either an increase in or the same number of ALL procedures performed in the coming year.Conclusion:The majority of surgeons who responded to the survey did not routinely reconstruct the ALL. Revision procedures and grade III pivot shift were the most cited indications for performing lateral augmentation. Anatomic reconstruction with hamstring was the most commonly used procedure, although there was no consensus among surgeons responding to the survey. Understanding the ALL and its contribution to knee stability is essential. For a community of physicians, it is useful to discover how fellow sports orthopaedic surgeons address ALL pathology to integrate effective and efficient treatment strategies into practice.

Background: Multimodal pain protocols have been effective for postsurgical pain control; however, no published protocol has been effective in eliminating opioid consumption. Purpose: To compare a multimodal nonopioid pain protocol versus traditional opioid medication for postoperative pain control in patients undergoing anterior cruciate ligament reconstruction (ACLR). Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 90 patients undergoing primary ACLR were assessed for participation. We performed a prospective, randomized controlled trial in accordance with the CONSORT (Consolidated Standards of Reporting Trials) 2010 statement. The study arms were a multimodal nonopioid analgesic protocol (acetaminophen, ketorolac, diazepam, gabapentin, and meloxicam) and a standard opioid regimen (hydrocodone-acetaminophen), and the primary outcome was postoperative visual analog scale (VAS) pain scores for 10 days. Secondary outcomes included patient-reported outcomes, complications, and satisfaction. The observers were blinded, and the patients were not blinded to the intervention. Results: A total of 9 patients did not meet inclusion criteria, and 19 patients declined participation. Thus, 62 patients were analyzed, with 28 patients randomized to the opioid group and 34 to the multimodal nonopioid group. Patients receiving the multimodal nonopioid pain regimen demonstrated significantly lower VAS scores compared with patients who received opioid pain medication ( P < .05). Patients were administered the Patient-Reported Outcomes Measurement and Information System Pain Interference Short Form, and no significant difference was found in patients’ preoperative scores (opioid group, 58.6 ± 7.9; multimodal nonopioid group, 57.5 ± 7.4; P = .385) and 1-week postoperative scores (opioid group, 66.3 ± 8.2; multimodal nonopioid group, 61.4 ± 8.8; P = .147). When we adjusted for possible confounders (age, sex, body mass index, graft type), no significant differences in pain control were found between the 2 groups. The most common adverse effects for both groups were drowsiness and constipation, with no difference between the groups. All patients in the multimodal nonopioid group reported satisfactory pain management. Conclusions: A multimodal nonopioid pain protocol provided at least equivalent pain control compared with traditional opioid analgesics in patients undergoing ACLR. Minimal side effects, which did not differ between groups, were noted, and all patients reported satisfaction with their pain management.

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