|Beitragstitel||Arthroscopy for painful unicompartmental knee arthroplasty (UKA) - a promising alternative to open revision with exchange of components?|
Only few studies discuss implant-retaining treatment options for painful total knee arthroplasties. Hardly any information exists for UKA. The purpose of this study was to determine structural pathologies and to evaluate if less invasive surgery (arthroscopy/mini-arthrotomy) provides successful treatment in painful UKA?
We retrospectively reviewed all implant-preserving operations (24 arthroscopies, 7 mini-arthrotomies, 4 combined) performed for painful UKA from may 2013 - march 2016. 33 patients (16 women, 17 men) with 35 UKA (26 medial, 5 lateral, 2 bicondylar - 15 right, 20 left knees) were included. Average patient age was 61 [45-84] years. Onset of symptoms averaged at 5,4 [0-63] months after index procedure and mean time to revision was 21,4 [4-72] months after UKA implantation. Mean follow-up after revision was 6 [1,5-29] months. Preoperative complaints were evaluated clinically and by standard X-rays. Additional SPECT-CTs were performed in 23 cases. The pain was refractory to conservative treatment.
Operative diagnoses included pseudomeniscus (30), osteophytes (21) - often causing impingement between femoral component and tibial eminence -, hypertrophic synovitis (9), meniscal tears (8), loose cement bodies (3), popliteus tendon impingement (1) and 2 lateral vertical patellectomies were required for patellofemoral impingement.
In 69,7% (23/33 patients) complete (18,2%) or partial (51,5%) pain relief was achieved. 30,3% (10/33 patients) complained about persistent pain (21,2%) or pain worsening (9,1%). The latter was caused by infection in 1 patient (1/33, 3%). This complication was treated successfully by 2 subsequent open revisions. Another 2 subsequent revisions were needed for persistent pain associated with aseptic loosening of both components and recurrence of osteophytes/pseudomeniscus.
If Spect-CT analysis provided suspicion for impingement by notch-osteophytes (16/23), diagnosis was confirmed intraoperatively in 81%. In contrast 5 false-positive tibial loosenings and 3 false-negative stable implants (2 tibial, 1 femoral) were diagnosed.
Arthroscopy (+/- mini-arthrotomy) provides reliable expectations to evaluate and treat painful UKA. Soft tissue problems can be resolved and osteophytes removed. Thus in 69,7% successful treatment was achieved with retention of the implant. SPECT-CT was not effective in analyzing implant stability but was helpful to detect impingement by osteophytes.