[Hip arthroscopy for painful endoprosthesis]

Hip arthroscopy for a painful endoprosthesis is performed to confirm and evaluate or detect pathologies (sampling for microbiology/histology, function), which are treated during the procedure or can indicate treatment options for the further course of the procedure.

Hip arthroscopy is indicated for the diagnostics of unclear persistent pain after implantation of a hip endoprosthesis (low-grade infection, metal reaction/metallosis, loosening/misplacement of prosthesis components) and for treatment (iliopsoas impingement, removal of biomechanically disruptive osteophytes, removal of free joint bodies and cam impingement in hip resurfacing arthroplasty, arthrolysis in cases of restricted movement).

Local infections with the exception of the diagnostics of a low-grade infection, bone tumors near the joint, periprosthetic fractures and extensive periarticular ossification or arthrofibrosis with involvement of periarticular soft tissue (relative) are contraindications.

As with arthroscopy of native hip joints, the procedure is performed on a fracture table. Strict attention must be paid to precise positioning to avoid complications. Joint distraction is not performed in cases of an implanted endoprosthesis because no additional information can be expected from viewing the surfaces of the bearing couples and there is a risk of damaging the surfaces. Arthroscopy is carried out in the peripheral compartment in 10-30° flexion in the basic position via an anterolateral (AL) and anterior portal (A) as standard. Synovial fluid and tissue samples should be taken regularly for microbiological or histological examination. After adhesiolysis and synovectomy the exposed endoprosthesis is inspected and its function dynamically assessed. If iliopsoas impingement is present the release is performed using the transcapsular technique.

The postoperative treatment regimen includes pain-adapted mobilization with full weight-bearing after the day of the operation onwards. Crutches are indicated for ca. 5 days to harmonize the gait pattern. Physiotherapy exercises with permitted full range of motion are carried out from the 1st postoperative day and should generally be continued until the 6th postoperative week.

In the period from 2010-2025, 22 hip arthroscopies were performed on 20 patients (14 female, 6 male; 2 female patients underwent arthroscopy twice) with an average age of 59 years (39-78 years) and an average of 3.5 years (0.75 months to 14.5 years) after arthroplasty. In each case 2 portals were created. The average operation time was 45 min (25-79 min). The results were evaluated after an average of 2.5 years (0.3-12.8 years), 4 patients underwent only diagnostic arthroscopy, an infection was detected twice and excluded two times. Of the infections one was treated with re-arthroscopy and one patient with an anterior cystic mass underwent an open reoperation. For the remaining 16 arthroscopies, overall 12 (75%) patients reported an improvement in preoperative symptoms. An iliopsoas release for impingement was performed 12 times. In 10 (83%) of these cases postoperative improvement with pain reduction was noted without any relevant loss of flexion strength. Mechanical joint symptoms were preoperatively present in 12 patients and were eliminated by the operation in 10 cases (83%). No complications were noted.