Don't Assume the Control Group Is Normal-People with Asymptomatic Tendon Pathology Have Higher Pressure Pain Thresholds.

Objective: Pain pressure thresholds (PPT) are used to study peripheral and central pain processing. In the tendon, pathological changes may exist without pain. This pilot study aimed to compare PPT between individuals with normal tendons and asymptomatic tendon pathology, and between individuals with and without a history of tendon pain. Methods: The patellar, Achilles, and supraspinatus tendons of 128 asymptomatic participants were examined with ultrasound. Global PPT average was determined using a digital algometer at the patellar tendon, quadriceps muscle, L3 spinous process, and deltoid muscle insertion. Participants were separated into three groups: (1) healthy control group (no pathology, no history of pain), (2) tendon pathology at any site without a history of pain, (3) history of tendon pain anywhere. Results: There were 92 controls, seven with asymptomatic pathology and 29 with a history of tendon pain. Asymptomatic tendon pathology at any site (without a history of pain) was associated with globally increased PPTs compared with controls (P < 0.001, pathology N = 7, N = 92 controls). Matched pair analysis remained significant (P < 0.004). A history of tendon pain was associated with globally increased PPTs compared with the control group (P = 0.026). Matched pair analysis was not significant (P = 0.122). Conclusions: Asymptomatic tendon pathology is associated with higher PPTs. These findings point toward central nervous system adaptations but in a novel way-central desensitization. This challenges the validity of conclusions drawn from PPT studies that do not verify normal structure in the control group; artificial inflation of control group data may incorrectly indicate decreased PPTs in the comparison group.

Asymptomatic Achilles tendon pathology is associated with a central fat distribution in men and a peripheral fat distribution in women: a cross sectional study of 298 individuals.

BACKGROUND: Adiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology. METHODS: The Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry. RESULTS: Asymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 +/- 10.4, 36.3 +/- 11.3, p < 0.001), had greater WHR (0.926 +/- 0.091, 0.875 +/- 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 +/- 0.186, 0.519 +/- 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 +/- 0.630, 2.022 +/- 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 +/- 10.0, 36.0 +/- 10.3, p = 0.008), had less total fat (17196 +/- 3173 g, 21626 +/- 7882 g, p = 0.009), trunk fat (7367 +/- 1662 g, 10087 +/- 4152 g, p = 0.003) and android fat (1117 +/- 324 g, 1616 +/- 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 +/- 0.321 g, 0.922 +/- 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002). CONCLUSIONS: Men with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men.

Effect of compaction drilling during ACL reconstruction with hamstrings on postoperative tunnel widening.

TYPE OF STUDY: This study investigates whether the amount of tibial and femoral bone tunnel enlargement following anterior cruciate ligament (ACL) reconstruction with hamstrings can be reduced by compaction bone tunnel drilling. METHODS: Patients undergoing primary ACL reconstruction with four-strand hamstrings (n = 26) were matched to either extraction drilling (n = 13) or compaction drilling (n = 13). Extracortical femoral fixation was by means of a 20 mm Endobutton CL and tibial fixation was by resorbable interference screw. A CT scan was performed on the second postoperative day and an average of 4 months (range 3.8-5 months) postoperatively in all patients. Tunnel enlargement was determined by digitally measuring the widths perpendicular to the long axis of the tunnels on an oblique coronal and axial plane. The CT measurements were compared to the intraoperative drill diameter. RESULTS: With extraction drilling the average tibial tunnel diameter proximal to the interference screw increased from 8.5 to 10.4 mm (P < 0.0001) and the average femoral tunnel from 8.0 to 10.6 mm (P < 0.0001). With compaction drilling it increased from 8.2 to 10.0 mm (P < 0.0001) and from 7.6 to 9.7 mm (P < 0.002), respectively. Tunnel widening was 22% on the tibial side for both groups and 33 versus 28% on the femoral side (P = 0.09) for extraction versus compaction drilling. CONCLUSION: There was a significant tibial and femoral tunnel widening on CT an average of only 4 months following ACL reconstruction with hamstrings. Compaction drilling with a stepped router did not prove to reduce the postoperative tunnel widening significantly. Tunnel widening was higher on the femoral side which could be related to the extracortical femoral fixation technique. LEVEL OF EVIDENCE: Level 4.

Comparative accuracy of magnetic resonance imaging and ultrasonography in confirming clinically diagnosed patellar tendinopathy.

BACKGROUND: Diagnosis of patellar tendinopathy is based primarily on clinical examination; however, it is commonplace to image the patellar tendon for diagnosis confirmation, with the imaging modalities of choice being magnetic resonance imaging (MRI) and ultrasonography (US). The comparative accuracy of these modalities has not been established. HYPOTHESIS: Magnetic resonance imaging and US have good (>80%) accuracy and show substantial agreement in confirming clinically diagnosed patellar tendinopathy. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Magnetic resonance imaging and US (gray scale [GS-US] and color Doppler [CD-US]) features of 30 participants with clinically diagnosed patellar tendinopathy and 33 activity-matched, asymptomatic participants were prospectively compared. Accuracy, sensitivity, specificity, positive and negative predictive values, and the likelihood of positive and negative test results were determined for each technique. RESULTS: The accuracy of MRI, GS-US, and CD-US was 70%, 83%, and 83%, respectively (P = .04; MRI vs GS-US). The likelihood of positive MRI, GS-US, and CD-US was 3.1, 4.8, and 11.6, respectively. The MRI and GS-US had equivalent specificity (82% vs 82%; P = 1.00); however, the sensitivity of GS-US was greater than MRI (87% vs 57%; P = .01). Sensitivity (70% vs 87%; P = .06) and specificity (94% vs 82%; P = .10) did not differ between CD-US and GS-US. CONCLUSIONS: Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. GS-US and CD-US may represent the best combination for confirming clinically diagnosed patellar tendinopathy because GS-US had the greatest sensitivity, while a positive CD-US test result indicated a strong likelihood an individual was symptomatic.