Tendinopathy remains a significant clinical challenge. Although there is some evidence that leukocyte-rich platelet-rich plasma can improve the symptoms of tendinopathy, more efficacious treatments will be required in the future to improve probability of successfully resolving this condition in athletes. Because optimal treatments are not currently available, there is a need to better understand the pathology of tendinopathy from the perspective of tendon progenitor cells (TPCs). TPCs isolated from normal and tendinopathy donors were characterized by their stem cell properties and proliferation capacities, along with their ability to become tenocytes under mechanical loading. The results showed a significant 2.6-fold increase in the viable cell population in tendinopathy versus normal donors. Although the percentage of self-renewing cells was similar, the total number of TPCs in tendinopathy was significantly higher (1.6-fold) than normal TPCs based on the colony formation assays. In contrast, TPCs from tendinopathy tissue showed significantly lower cellular proliferation rate by cumulative population doublings. Next, the expanded TPCs from both tissues successfully demonstrated the trilineage differentiation capabilities with specific gene markers, staining, and biochemical assays. To induce tenogenic differentiation, stretchable silicone wells were designed and fabricated, plus the creation of an adaptor platform used on a syringe pump for mechanical stretch. This economic design provided the adequate cyclic loading to drive tenogenic differentiation. With these devices, the stretch duration was optimized and showed the significant increase in scleraxis (SCX) and tenomodulin (TNMD) expression at 2.60 (fold change) and 3.86 (fold change in logarithm), respectively, by reverse transcription-quantitative polymerase chain reaction in normal TPCs after stretch. This assay also demonstrated the widespread cell reorientation following stretch in normal TPCs. In contrast, the mechanical loading did not increase the SCX gene expression; TNMD expression remained undetectable, and cell realignment was significantly less in tendinopathy TPCs. In addition, western blot analysis confirmed the elevated TNMD protein expression in normal TPCs following stretch and the lack of expression in tendinopathy TPCs. In summary, tendinopathy TPCs were unable to differentiate into tenocytes following mechanical stretch. Future studies may aim to reprogram tendinopathy TPCs to allow tenogenic induction.

Background: The statistical significance of randomized controlled trials (RCTs) and comparative studies is often conveyed utilizing the P value. However, P values are an imperfect measure and may be vulnerable to a small number of outcome reversals to alter statistical significance. The interpretation of the statistical strength of these studies may be aided by the inclusion of a Fragility Index (FI) and Fragility Quotient (FQ). This study examines the statistical stability of studies comparing operative vs nonoperative management for Achilles tendon rupture. Methods: A systematic search was performed of 10 orthopaedic journals between 2000 and 2021 for comparative studies focusing on management of Achilles tendon rupture reporting dichotomous outcome measures. FI for each outcome was determined by the number of event reversals necessary to alter significance ( P < .05). FQ was calculated by dividing the FI by the respective sample size. Additional subgroup analyses were performed. Results: Of 8020 studies screened, 1062 met initial search criteria with 17 comparative studies ultimately included for analysis, 10 of which were RCTs. A total of 40 outcomes were examined. Overall, the median FI was 2.5 (interquartile range [IQR] 2-4), the mean FI was 2.90 (±1.58), the median FQ was 0.032 (IQR 0.012-0.069), and the mean FQ was 0.049 (±0.062). The FI was less than the number of patients lost to follow-up for 78% of outcomes. Conclusion: Studies examining the efficacy of operative vs nonoperative management of Achilles tendon rupture may not be as statistically stable as previously thought. The average number of outcome reversals needed to alter the significance of a given study was 2.90. Future analyses may benefit from the inclusion of a fragility index and a fragility quotient in their statistical analyses.

Background: Comparative studies and randomized controlled trials (RCTs) often use the P (probability) value to convey the statistical significance of their findings. P values are an imperfect measure, however, and are vulnerable to a small number of outcome reversals to alter statistical significance. The inclusion of a fragility index (FI) and fragility quotient (FQ) may aid in the interpretation of a study’s statistical strength. Purpose/Hypothesis: The purpose of this study was to examine the statistical stability of studies comparing single-row to double-row rotator cuff repair. It was hypothesized that the findings of these studies would be vulnerable to a small number of outcome event reversals, often fewer than the number of patients lost to follow-up. Study Design: Systematic review; Level of evidence, 3. Methods: We analyzed comparative studies and RCTs on primary single-row versus double-row rotator cuff repair that were published between 2000 and 2021 in 10 leading orthopaedic journals. Statistical significance was defined as a P < .05. The FI for each outcome was determined by the number of event reversals necessary to alter significance. The FQ was calculated by dividing the FI by the respective sample size. Results: Of 4896 studies screened, 22 comparative studies, 10 of which were RCTs, were ultimately included for analysis. A total of 74 outcomes were examined. Overall, the median FI was 2 (interquartile range [IQR], 1-3), and the median FQ was 0.035 (IQR, 0.020-0.057). The mean FI was 2.55 ± 1.29, and the mean FQ was 0.043 ± 0.027. In 64% of outcomes, the FI was less than the number of patients lost to follow-up.) Additionally, 81% of significant outcomes needed just a single outcome reversal to lose their significance. Conclusion: Over half of the studies currently used to guide clinical practice have a number of patients lost to follow-up greater than their FI. The results of these studies should be interpreted within the context of these limitations. Future analyses may benefit from the inclusion of the FI and the FQ in their statistical analyses.

IntroductionAlthough a substantial portion of the United States population has been infected with and recovered from Coronavirus , many patients may have persistent symptoms and complications from disease-driven respiratory disease, arrhythmias, and venous thromboembolism (VTE). With institutions resuming elective total joint arthroplasties (TJA), it is unclear whether a prior resolved diagnosis of COVID has any implications on postoperative outcomes. MethodsAll elective TJA performed in 2021 at our institution were retrospectively reviewed and a history of prior COVID+ result recorded. Baseline demographics, days from prior COVID+ result to surgery date, preoperative methicillin-resistant Staphylococcus aureus (MRSA) nares colonization, and laboratory markers were obtained to determine baseline characteristics. Postoperative estimated blood loss (EBL), length of stay (LOS), rate of revision surgery, and discharge destination were compared between groups. Perioperative and postoperative rates of VTE, urinary tract infection (UTI), pneumonia, postoperative oxygen supplementation, cardiac arrhythmia, renal disease, sepsis, and periprosthetic joint infections within six months of surgery were recorded. ResultsOf the 155 elective TJA performed in 2021, 24 patients had a prior COVID+ diagnosis with a mean of 253 days from positive result to surgery date. There were no significant differences in baseline demographics, comorbidities, and preoperative lab markers between groups. Surgeries on patients with a prior COVID+ had a significantly higher EBL (260 vs 175cc), but postoperative outcomes of VTE, UTI, pneumonia, oxygen supplementation requirement, nares MRSA+, cardiac disease, and infection rates between groups were similar. Bivariate logistic regression revealed increased days from COVID+ diagnosis (>6 months) to surgery date were associated with a shorter LOS. ConclusionAlthough a prior COVID+ diagnosis had increased intraoperative blood loss, there were no significant differences in respiratory, infectious, cardiac, and thromboembolic complications up to six months after elective TJA. This study suggests that asymptomatic C+ patients receiving elective TJA do not require more aggressive prophylactic anticoagulation or antibiotic regimens to prevent VTE or perioperative infections. As institutions around the nation resume pre-COVID rates of arthroplasty surgeries, a prior diagnosis of COVID appears to have no effects on postoperative complications.

Background: Chronic patellar tendinosis is an overuse injury of the patellar tendon that commonly afflicts jumping athletes. Indications: For patients with refractory symptoms that do not respond to extensive physical therapy and rest, surgical management may be considered. Although both open and arthroscopic treatments have been described, arthroscopic treatment allows for more direct access to the diseased dorsal portion of the tendon and allows for faster return to activities and sport. Technique Description: Arthroscopic treatment involves debridement of the diseased portion of the patella tendon and osteoplasty of the distal pole of the patella. The infrapatellar fat pad is first debrided using an arthroscopic shaver and radiofrequency ablation device to the level of the dorsal surface of the patellar tendon. Under direct arthroscopic visualization and corresponding to the location of edema noted on the magnetic resonance image, the diseased portion of the patellar tendon is gently debrided with an arthroscopic shaver. Next, an osteoplasty of the distal pole of the patella is performed to facilitate bleeding and healing of the diseased tendon as well as eliminate any mechanical impingement. Any calcifications within the enthesis can be removed using an arthroscopic biter and resector. An arthroscopic resector is then used to decorticate and smoothen the distal pole of the patella to the level of healthy, bleeding cancellous bone. Results: Significant improvements in pain and function have been reported with arthroscopic treatment for chronic patellar tendinosis. Patients can expect a 90% return to sport rate following the procedure, with return to preinjury function as soon as 3 to 5 months. This procedure is well tolerated with minimal complications reported. Discussion: Arthroscopic patellar tendon debridement and distal pole osteoplasty can be used to treat chronic patellar tendinosis refractory to nonoperative treatment. Improvements in pain and function have been reported with this technique, along with a faster return to sport compared with traditional open techniques.