Saturday, June 5, 2021

Polymethylmethacrylate spacers for shoulder periprosthetic infections

Spacers for Life: High Mortality Rate associated with Definitive treatment of shoulder periprosthetic infection with permanent antibiotic spacer

Periprosthetic infections of the shoulder have been treated with a number of different surgical prototocols, including washout with prosthesis retention, washout with partial prosthesis retention, complete prosthesis exchange at a single stage, two stage revision with implant removal and insertion of an antibiotic spacer followed by a delayed prosthesis re-insertion, implant removal and spacer insertion without subsequent revision, and resection arthroplasty. 

These authors reviewed their experience with 17 patients (mean age of  62.4 years (range 50-73); ten female). Revision with pacer placement was performed at a mean 6.1 years (range 0.48 - 14.9 years) following index arthroplasty. These patients had had an average of 2.2 procedures after the index arthroplasty prior to spacer placement.

The most common organisms were Cutibacterium acnes (6), Methicillin sensitive Staphylococcus aureus (MSSA) (6), Methicillin resistant  Staphylococcus aureus (MRSA) (2), coagulase negative Staphylococcus (2), Serratia marcescens (1), gram-positive cocci (1), Enterobacter faecalis (1), Enterobacter cloacae (1), Diphtheroids (1),  and culture negative (1). Eight had a draining sinus, purulence was found at surgery in thirteen cases, ten had elevated sedimentation rates. Five patients had spacer exchange after initial spacer placement.

Apparently the spacers used in these patients were hand crated by the surgeon, either with a stem containing a metal wire to aid in retrieval

or without a stem.

The mortality rate was 9/17 (52.9%). 

Of the 8 surviving patients, the mean ASES score was 33.9 (range 13.3-24 80.0).

Comment: There are two reasons for chronic spacer placement (rather than proceeding with the second stage of a two-stage revision): (1) the patient does not want further surgery (because of acceptable shoulder function or out of fear of further complications) and (2) the surgeon decides that either the patient or the shoulder is not suitable for additional shoulder reconstruction. In addition, as pointed out in this article, some patients expire before a second state could be performed.

As indicated in another article "Prolonged implantation of an antibiotic cement spacer for management of shoulder sepsis in compromised patients" (see this link), patients can have acceptable function with long standing spacer placement. On the other hand, as indicated in this link, spacers can be associated substantial complications.

It is of interest that a commonly used commercially available spacer 

contains Gentamycin, which is not particularly effective against Cutibacterium (the commonest organism found in shoulder periprosthetic infections).

Our primary indications for spacer placement are: (1) presence of a draining sinus, (2) purulence, (3) infection with organisms other than Cutibacterium or coagulase negative Staph, and (4) failed single stage revision.

One of the issues with chronic spacer placement is progressive glenoid erosion as shown in the case below

immediate post operative radiograph

radiograph at one year after spacer implantation

Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The total shoulder arthroplasty (see this link).
The ream and run technique is shown in this link.
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).