Allergic reaction and metal hypersensitivity after shoulder joint replacement

PURPOSE

Metal ion release may cause local and systemic effects and induce hypersensitivity reactions. The aim of our study is first to determine if implant-related hypersensitivity correlates to patient symptoms or not; second, to assess the rate of hypersensitivity and allergies in shoulder arthroplasty.

METHODS

Forty patients with shoulder replacements performed between 2015 and 2017 were studied with minimum 2-year follow-up; no patient had prior metal implants. Each patient underwent radiographic and clinical evaluation using the Constant-Murley Score (CMS), 22 metal and cement haptens patch testing, serum and urine tests to evaluate 12 metals concentration, and a personal occupational medicine interview.

RESULTS

At follow-up (average 45 ± 10.7 months), the mean CMS was 76 ± 15.9; no clinical complications or radiographic signs of loosening were detected; two nickel sulfate (5%), 1 benzoyl peroxide (2.5%) and 1 potassium dichromate (2.5%) positive findings were found, but all these patients were asymptomatic. There was an increase in serum aluminum, urinary aluminum and urinary chromium levels of 1.74, 3.40 and 1.83 times the baseline, respectively. No significant difference in metal ion concentrations were found when patients were stratified according to gender, date of surgery, type of surgery, and type of implant.

CONCLUSIONS

Shoulder arthroplasty is a source of metal ion release and might act as a sensitizing exposure. However, patch test positivity does not seem to correlate to hypersensitivity cutaneous manifestations or poor clinical results. Laboratory data showed small constant ion release over time, regardless of gender, type of shoulder replacement and implant used.

LEVELS OF EVIDENCE

Level II.

Thompson calf squeezing test: clinical and ultrasound correlations in the follow up of Achille's tenorraphy

In the follow up of Achille's tenorraphy, negativization of Thompson calf queezing test is not always omogeneous and absolute. Aim of the paper is to correlate Thompson test to different anatomical-ultrasound and functional parameters. We investigated clinically and by ultrasound 61 patients operated on of Achille's tenorraphy at Novara Hospital with follow-up of 10 to 46 months. Negative controls were contralateral tendons. We excluded patients with previous and/or contralateral Achille's tendon ruptures, those operated after 7 days, diabetics or with autoimmune diseases, if used topic steroids, < 18 years, those rejecting the study. Measured parameters were: age, gender, height, weight, side, open vs percutaneous approach, time from operation, neutral angle and range of motion of the ankle, maximal circumference of the leg, Single Heel Rise Test, Visual-Analogue-Scale Foot and Ankle (VAS FA) score; with ultrasound: length of tendons, mio-tendinous U.S.-structure, dynamic diastasis of tendon scar, tendon sliding. Thompson test is positive if no plantar-flexion of the foot occurs at calf squeezing, negative if plantar-flexion is normal (75% patients) and intermediate if reduced or slight reactive (25%).We found correlation of Thompson test with age (p<0,05) and with tendon length (p>0,05), being intermediate tests more represented in older patients and in those with longer healed tendons. In conclusion post-operative negativization of Thompson test can be incomplete as observed in older patients and in those healed with elongated tendon.