Treatment Algorithm for the Infected Shoulder Joint Replacement
Authors: Markus Wambacher
References: Presented at ICSES 2010
Infection rate in anatomical shoulder replacement ranges from 0 to 3,5% and is higher in reverse shoulder arthroplasty (3-20%),1 this data exists for the manifest infection, the rate of low grade infection in shoulder replacement and in case of shoulder revision surgery remains unknown and is supposed higher then expected. Eradication of infected shoulder replacement is a demanding surgery and a strict treatment algorithm is mandatory.4 Recommendations in the literature regarding infections in shoulder replacement are contradictory and contrary discussed. The infection may occur by intra-operative contamination or by haematogenous spreading. The mechanism has different stages, starting with adhesion and accumulation and ends with a biofilm formation on the implant, where the bacteriums are non-sensitive for the antibiotics. Spectrum of germs represents in most cases low pathogenic bacteriums of the skin (coagulase negative Staph. aureus, Staph. epidermidis, Proprionibacterium acne), Pseudomonas, Enterococcus, E.coli. A low immune status, multiple previous surgeries and a large death space as in reversed shoulder arthroplasty increases the risk of infection. The infection may be acute, subacute, chronic (+/- fistula) or a low-grade infection. Treatment algorithm in case of infected shoulder replacement starts with an intensive interdisciplinary microbiological assessment: preoperative (puncture) or intraoperative (multiple tissue cultures from different layers including sutures, bone, cement, metal peaces). Its mandatory to have pre- and intra-operative stop of antibiotics therapy. Swabs from the probably infected shoulder are not sensitive enough and should be avoided. Immediate transport in sterile containers with sodium chloride (no blood) with short transport ways to ensure an immediate cultivation. Cultivation time should be at least 3 weeks to detect also Proprioni and low grad infections. A new method is an ultrasound irradiation of the explanted prosthesis (sonication 2). In an analysis of all of our shoulder revision surgeries (manifest infections where excluded from this analysis), where we have taken tissue cultures in all cases, we found positive cultures in 50% of the cases; a positive result was achieved not until 48 hours (except of one) after start of cultivation (48 hours are the standard cultivation time!). In about 70% the bacterium was coagulase negative Staph. aureus. In summery there is 50% risk in revision cases to implant a prosthesis in low grad infected shoulder. Treatment has to be a combination with antibiotics therapy and surgical treatment. Surgical treatment is controversial in the literature regarding one or two stage exchange of the prosthesis 4. Our protocol includes debridement without change only in case of acute infection; in the other cases we recommend a two stage procedure with temporary cement spacer implantation (in our opinion the risk of remaining infection may be to high in one stage revisions). After taking the tissue cultures we start with wideband antibiotics therapy (Cephalosporin 2.generation) and continue with a combination therapy after antibiogram in positive cultures followed by long time (4 weeks) therapy with oral application of antibiotics (egg Fusidinacid, Linezolid).
Explantation of the stem of the prosthesis is the most challenging part of the revision with many intraoperative complications and problems as iatrogene fractures of the humerus, destruction of the footprint and the tendon of the supraspinatus in case of protruding components of the prosthetic shaft (egg fins), stocked shaft, remaining cement, osteoporotic bone. A stepwise transhumeral approach3 may be useful to avoid destruction of the shaft as well as a collection of cement removing devices for stepwise careful removal of the remaining cement, alternative using ultrasound devices (Caspar).
In case of multiple revisions, the surgeon will be confronted with scared tissue increasing the risk of damage of neurovascular structures and leading to limitation of range of motion and function after the final reimplantation. Reimplantation of the prosthesis after infection free interval of 6 weeks (no clinical sign of infection, normal CRP and leucos). Antibiotics break at the latest one week before reimplantation of the prosthesis. If there are any concerns, we repeat the procedure with exchange of the spacer and new tissue cultures to avoid reinfection. Eradication of infected shoulder replacement may be achieved with a strict treatment algorithm, but may also lead to a limited goal functional outcome. Careful planning and careful surgical technique especially in revision surgery (with the knowledge of a possible low grad infection) and reversed shoulder arthroplasty may lower the incidence of shoulder joint infections.
- Instructional Course: Revision shoulder arthroplasty reverse prosthesis: where we are, where we are going. 19th Congress of SECEC/ESSSE, Rome 2005
- Ackermann Y et al (2010) Improved Diagnosis of Periprosthetic Joint Infection by Multiplex PCR of Sonication Fluid from Removed Implants. J Clin Microbiol. Apr;48(4):1208-14
- Gohlke F et al (2007) Revision of Failed Fracture Hemiarthroplasties to Reverse Total Shoulder Prosthesis through the Transhumeral Approach Method Incorporating a Pectoralis-Major-Pedicled Bone Window. Oper Orthop Traumatol. Jun;19(2):185-208.
- Zimmerli W et al (2004) Prosthetic-joint infections. N Engl J Med. 14; 351(16):1645-54. Review.