Estimation of Patient Acceptable Symptom State (PASS) and Treatment Failure (TF) Threshold Values for the Achilles Tendon Total Rupture Score (ATRS) at 6 Months, 1 Year, and 2 Years After Acute Achilles Tendon Rupture

Defining the Patient Acceptable Symptom State (PASS) for PROMIS After Total Ankle Replacement

BACKGROUND

Although patient-reported outcomes (PROs), such as the Patient-Reported Outcomes Measurement Information System (PROMIS), are a key element of evaluating success after total ankle replacement (TAR), many do not explicitly state a key factor of postoperative success: is the patient satisfied with their outcome after TAR? The patient acceptable symptom state (PASS) represents the symptom threshold beyond which patients consider themselves well. This study aimed to establish the PROMIS thresholds for the PASS in a primary cohort of TAR patients.

METHODS

This single-institution study included 127 primary TAR patients with preoperative and 2-year postoperative PROMIS scores. At 2 years postoperatively, patients answered 2 PASS anchor questions (Satisfaction, Delighted-Terrible scale) with Likert-scale responses. PASS thresholds with 95% confidence intervals (CIs) were calculated from PROMIS scores using an anchor-based method. Using a bootstrapping technique with 1,000 iterations, the Youden index was calculated to determine the best specificity and sensitivity coordinates to maximize their combination. Finally, preoperative variables associated with the likelihood of achieving the PASS were assessed.

RESULTS

There was a strong association between PASS thresholds and PROMIS domains, especially Pain Interference (PASS threshold of <56.0, area under the receiver operating characteristic curve [AUC] = 0.940), Pain Intensity (<48.4, AUC = 0.936), and Physical Function (>44.7, AUC = 0.883). The likelihood of achieving the PASS was not affected by age, race, gender, American Society of Anesthesiologists (ASA) class, body mass index, or severity of ankle deformity. Patients with worse preoperative Physical Function and Global Mental Health scores were less likely to meet the PASS threshold for Physical Function postoperatively (p = 0.028 and 0.041).

CONCLUSIONS

The ability to reach the PASS after TAR was most strongly associated with postoperative PROMIS pain scores. However, PASS thresholds were generally poorer than population means. This demonstrates that patients do not need to reach normal pain or physical function levels to have an acceptable symptom state after TAR.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Muscle fascicle and sarcomere adaptation in response to Achilles tendon elongation in an animal model

Permanent loss of muscle function seen after an Achilles tendon rupture may partly be explained by tendon elongation and accompanying shortening of the muscle. Muscle fascicle length shortens, serial sarcomere number is reduced, and the sarcomere length is unchanged after Achilles tendon transection (ATT), and these changes are mitigated with suturing. The method involved in this study was a controlled laboratory study. Two groups of rats underwent ATT on one side with a contralateral control (CTRL): A) ATT with 3 mm removal of the Achilles tendon and no suturing (substantial tendon elongation), and B) ATT with suture repair (minimal tendon elongation). The operated limb was immobilized for 2 wk to reduce load. Four weeks after surgery the rats were euthanized, and hindlimbs were analyzed for tendon length, gastrocnemius medialis (GM) muscle mass, length, fascicle length, sarcomere number and length. No differences were observed between the groups, and in both groups the Achilles tendon length was longer (15.2%, P < 0.001), GM muscle mass was smaller (17.5%, P < 0.001), and muscle length was shorter (8.2%, P < 0.001) on the ATT compared with CTRL side. GM fascicle length was shorter (11.2%, P < 0.001), and sarcomere number was lower (13.8%, P < 0.001) on the ATT side in all regions. Sarcomere length was greater in the proximal (5.8%, P < 0.001) and mid (4.2%, P = 0.003), but not distal region on the ATT side. In this animal model, regardless of suturing, ATT resulted in tendon elongation, loss of muscle mass and length, and reduced serial sarcomere number, which resulted in an "overshoot" lengthening of the sarcomeres.NEW & NOTEWORTHY Following acute Achilles tendon rupture, patients are often left with functional deficits. The specific reason remains largely unknown. The shortened muscle leads to reduced fascicle length, in turn leading to adaptation by reduced serial sarcomere numbers. Surprisingly, this adaptation appears to "overshoot" and lead to increased sarcomere length. The present animal model advances understanding of how muscle sarcomeres, which are difficult to measure in humans, are affected when undue elongation takes place after tendon rupture.

Achilles Tendon Tissue Turnover Before and Immediately After an Acute Rupture

BACKGROUND

An Achilles tendon rupture (ATR) is a frequent injury and results in the activation of tendon cells and collagen expression, but it is unknown to what extent turnover of the tendon matrix is altered before or after a rupture.

PURPOSE/HYPOTHESIS

The purpose of this study was to characterize tendon tissue turnover before and immediately after an acute rupture in patients. It was hypothesized that a rupture would result in pronounced collagen synthesis in the early phase (first 2 weeks) after the injury.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The study included patients (N = 18) eligible for surgery after an ATR. At the time of inclusion, the patients ingested deuterium oxide (2H2O) orally, and on the day of surgery (within 14 days of the injury), they received a 3-hour flood-primed infusion of an 15N-proline tracer. During surgery, the patients had 1 biopsy specimen taken from the ruptured part of the Achilles tendon and 1 that was 3 to 5 cm proximal to the rupture as a control. The biopsy specimens were analyzed for carbon-14 (14C) levels in the tissue to calculate long-term turnover (years), incorporation of 2H-alanine (from 2H2O) into the tissue to calculate the fractional synthesis rate (FSR) of proteins in the short term (days), and incorporation of 15N-proline into the tissue to calculate the acute FSR (hours).

RESULTS

Both the rupture and the control samples showed consistently lower levels of 14C compared with the predicted level of 14C in a healthy tendon, which indicated increased tendon turnover in a fraction (48% newly synthesized) of the Achilles tendon already for a prolonged period before the rupture. Over the first days after the rupture, the synthesis rate for collagen was relatively constant, and the average synthesis rate on the day of surgery (2-14 days after the rupture) was 0.025% per hour, irrespective of the length of time after a rupture and the site of sampling (rupture vs control). No differences were found in the FSR between the rupture and control samples in the days after the rupture.

CONCLUSION

Higher than normal tissue turnover in the Achilles tendon before a rupture indicated that changes in the tendon tissue preceded the injury. In addition, we observed no increase in tendon collagen tissue turnover in the first 2 weeks after an ATR. This favors the view that an increase in the formation of new tendon collagen is not an immediate phenomenon during the regeneration of ruptured tendons in patients.

REGISTRATION

NCT03931486 (ClinicalTrials.gov identifier).

Treatment outcome at 1 year did not differ between use of cast or walker in the first 3 weeks after an acute Achilles tendon rupture. A registry study of 1304 patients from the Danish Achilles tendon database

BACKGROUND

The best choice of orthosis in the treatment of acute Achilles tendon rupture is still under debate.

OBJECTIVE

To investigate if choice of orthosis in the first 3 weeks of treatment affected patient reported outcome (Achilles tendon Total Rupture Score (ATRS)), tendon elongation (Achilles Tendon Resting Angle (ATRA) and Heel Rise Height (HRH)) and re-rupture.

METHODS

Registry study in the Danish Achilles tendon Database. Patients treated with cast and patients treated with walker in the first 3 weeks of treatment were compared using a linear mixed-effects model adjusted for potential confounders.

RESULTS

1304 patients were included in the study. No clinically relevant difference was found: Adjusted mean difference (using walker the whole period as reference)(95% CI) ATRS after 1 year = 0.1(-3.0; 4.1), ATRS after 6 months = 2.0(-4.5; 5.8), ATRS after 2 years = 3.0(-0.7; 7.0), HRH difference = 0.6(-6.6; 8.2), ATRA difference = 0.03°(-1.5; 1.6), re-rupture(odds ratio) = 0.812(0.4; 1.61).

CONCLUSION

Patients treated with cast the first 3 weeks after acute Achilles tendon rupture did not have better treatment outcome than patients treated with walker.

Involvement of Bacteria in the Pathological Changes Before Achilles Tendon Rupture: A Case Series Investigating 16S rDNA in 20 Consecutive Ruptures

Background

The source of the pathological changes that occur before an acute Achilles tendon rupture (ATR) is not fully understood. Bacterial DNA has previously been detected in samples from ruptured Achilles tendons, suggesting a pathogenic role of bacteria in ATR.

Purpose/Hypothesis

The purpose of this study was to investigate if DNA from bacteria was present in acutely ruptured Achilles tendons. We hypothesized that 20% to 30% of the samples from the rupture site and no samples from healthy tissue would be positive for bacterial DNA.

Study Design

Case series; Level of evidence, 4.

Methods

This study included 20 consecutive patients scheduled for surgical repair of an acute ATR. Tendon biopsy specimens were taken from the rupture site and from the healthy tendon tissue proximal to the rupture to act as a control. Samples were blinded to the technician and analyzed using polymerase chain reaction targeted to the bacterial 16S rDNA gene and Sanger sequencing to identify the bacterial species present. McNemar test for paired proportions was performed to test for statistically significant differences in the number of samples positive for bacterial DNA between the ruptured and control regions of the Achilles tendon.

Results

Of the 20 patients, 1 (5%) had a positive sample with bacterial DNA from the ruptured part of the Achilles tendon. The same patient also had a positive control sample, although with different bacterial DNA. An additional patient had a positive control sample. There was no statistically significant difference in the number of bacterial DNA-positive samples between the ruptured and control regions of the Achilles tendon. The bacteria found (Staphylococcus sp, Micrococcus sp, and Staphylococcus epidermidis) were normal commensal organisms on the human skin.

Conclusion

Bacterial DNA was infrequent in tissue from ruptured Achilles tendons and, if identified, likely was a result of contamination. This suggests that bacteria are not involved in the pathological changes occurring before rupture of the Achilles tendon.