gms | German Medical Science

Fragestellung: The incidence of deep surgical site infections following HTO ranges between 0.4 to 4.7%. It is a severe complication, requires further surgeries and can lead to an arthroplasty, knee arthrodesis or even an above-knee amputation. The aim of this study was to proof that this newly developed salvage algorithm for infected HTO with unstable bone situation leads to an infect-free status and union of the osteotomy. The second objective was to show that correct limb alignment can be restored. And third, knee function after treatment is equal to patients who underwent HTO.

Methodik: The study consisted of 7 patients treated between 2017 and 2019 in the septic department of a level-1 trauma centre. All patients had periimplant infections following HTO treatment. Infections occurred within 83 days (range 24 to 191) after HTO. All patients underwent the "RESTORE" algorithm: patients received (1) REmoval of the HTO hardware and extensive debridement; (2) the osteotomy was Stabilized with a hexapod external fixator (TSF); (3) the osteotomy gap was Opened and (4) the alignment was Reconstructed using the TSF aiming for the intended limb alignment of the initial HTO. Patient related outcome (SF-12, KOOS, Oxford Knee Score) was assessed 22-36 months after removal of the TSF.

Ergebnisse: Average duration of bone healing or removal of the TSF was 24 weeks (range 11-35). In all cases, the limb could be saved and the previously planned mechanical axis deviation (MAD) of the lower limb could be kept or restored. All patients reached full extension of the knee joint and at least 110° of flexion (range 110°-130°). KOOS test results shows slightly lowered values than healthy samples, but substantially better values than patients awaiting HTO. OKS and SF-12 measurement indicates that patients have undergone the same improvement as patients with successful TKA or HTO.

Schlussfolgerung: The "RESTORE" algorithm is a safe and effective salvage procedure of patients suffering from deep surgical site infections with unstable bone situation after HTO. The concept allows to save the limb and even to obtain the previously planned limb alignment. Due to the possibility of initial full weight bearing, the risk of higher morbidity caused by immobilization is minimized. However, TSF treatment is a demanding procedure and should be performed by experienced surgeons.