An antibiotic hip spacer is a specialized, temporary medical device designed to manage infection within the hip joint following the removal of an infected prosthetic hip replacement. This device is a short-term measure used during the initial phase of a two-stage surgical process known as revision arthroplasty, which is the standard treatment for a prosthetic joint infection. The spacer’s primary purpose is to deliver a high concentration of antibiotics directly to the infected area while maintaining the joint space and surrounding soft tissues before a new, permanent implant can be placed.
Visual Anatomy and Composition
The physical appearance of an antibiotic hip spacer is directly related to its function as a temporary replacement for the removed hip prosthesis. Spacers are constructed predominantly from specialized bone cement, polymethyl methacrylate or PMMA, which is mixed with powdered antibiotics. The resulting material is generally white or bone-colored and can have a somewhat rough or porous surface texture due to the inclusion of the antibiotic powder.
Spacers come in two main forms: articulating and non-articulating (static). An articulating spacer is shaped to mimic the original ball-and-socket structure of the hip joint, featuring a femoral stem and a rounded head, allowing for some joint movement. Conversely, a non-articulating spacer is typically a bulkier, non-mobile mass of cement filling the void left by the removed implant components. The surgeon may custom-make the spacer during the operation by molding the cement, or they may opt for a pre-manufactured, commercially available spacer that is already formed into the prosthetic shape.
Primary Function: Targeting Infection
The spacer’s design as an antibiotic-loaded cement structure transforms it into a localized drug delivery system. High doses of specific antibiotics, often chosen based on the bacteria causing the infection, are incorporated into the PMMA. This process allows the antibiotics to slowly “elute” from the cement matrix over a period of weeks.
This mechanism ensures an extremely high concentration of antibacterial agents is released directly into the joint capsule and surrounding tissue, targeting the bacterial biofilm that often forms on implants. The localized delivery of the antibiotic is significantly more effective at eradicating the infection than systemic (intravenous) antibiotics alone. The spacer clears the infection while preserving the joint’s general shape and the tension of the surrounding muscles.
Patient Experience: Mobility and Restrictions
Living with an antibiotic hip spacer involves significant physical limitations, as the temporary device provides reduced stability compared to a permanent implant. Most patients are placed on strict weight-bearing restrictions, typically either non-weight bearing (NWB) or touch-down weight-bearing (TDWB). These restrictions prevent the temporary cement structure from fracturing or subsiding into the bone, which could damage the remaining bone stock.
Mobility aids such as crutches or a walker are required to move around, and the overall pace of daily life is greatly reduced. The spacer itself can sometimes cause discomfort, a feeling of instability, or even an audible “clunking” or shifting sensation during movement. The spacer remains implanted for a period determined by the infection’s severity and the patient’s response, often ranging from six to twelve weeks.
Surgical Timeline: Placement and Removal
The two-stage revision arthroplasty is divided into distinct surgical procedures. Stage 1 involves the removal of all infected prosthetic components and surrounding diseased tissue, a step known as debridement. Immediately following debridement, the antibiotic-loaded cement spacer is implanted into the joint space.
The spacer remains in place while the patient receives additional intravenous or oral antibiotic therapy to ensure complete eradication of the infection. Stage 2, the final step, is performed after blood tests confirm that the infection markers have normalized and the site is clear of bacteria. The temporary spacer is removed, and a brand-new, permanent hip prosthesis is implanted, completing the treatment process.