Complications of antibiotic cement spacers used for elbow infections.

BACKGROUND: Antibiotic cement spacers have been widely used in the treatment of joint infections. There are no commercially available antibiotic spacers for the elbow. Instead, they are typically fashioned by the surgeon at the time of surgery using cement alone or a combination of cement with sutures, Steinmann pins, external fixator components, or elbow arthroplasty components. There is no consensus regarding the ideal elbow antibiotic spacer and no previous studies have examined the complications associated with these handmade implants in relation to their unique structural design. METHODS: We retrospectively reviewed 55 patients who had 78 static antibiotic cement spacers implanted between January 1998 and February 2021 as part of a 2-stage treatment plan for infection of an elbow arthroplasty, other elbow surgery, or primary elbow infection. Several antibiotic spacer structures were used during the study period. For analysis purposes, the spacers were classified into linked and unlinked spacers based on whether there was a linking mechanism between the humerus and the ulna. Complications related to these spacers that occurred either during the implantation, between implantation and removal, or during removal were recorded and analyzed from chart review and follow-up x rays. Reoperations due to spacer-related complications were also recorded. RESULTS: Among the 55 patients (78 spacers), there were 23 complications, including 17 minor and 6 major complications. The most common complication of unlinked spacers (intramedullary [IM] dowels, beads and cap spacer) was spacer displacement. Other complications included IM dowel fracture and difficulty locating beads during spacer removal. The major complications of linked cement spacers included two periprosthetic humerus fractures after internal external fixator cement spacers and re-operation due to breakage and displacement of one bushing cement spacer. The major complications of unlinked cement spacers included two reoperations due to IM dowel displacement and one reoperation due to displacement of beads. Among patients who had removal of all components and those with native joints, there was no statistically significant difference between internal external fixator cement spacers and unlinked cement spacers in minor complication rates (30% vs. 16%, P = .16), major complication rates (7% vs. 8%, P = .85) and reoperation rates (0% vs. 8%, P = .12). CONCLUSIONS: Static handmade antibiotic elbow spacers have unique complications related to their structural designs. The most common complication of linked and nonlinked cement spacers were failure of the linking mechanism and displacement, respectively. Surgeons should keep in mind the possible complications of different structures of cement spacers when choosing 1 antibiotic spacer structure over another.

Biomechanical Analysis of Implanted Clavicle Hook Plates With Different Implant Depths and Materials in the Acromioclavicular Joint: A Finite Element Analysis Study.

Clinical implantation of clavicle hook plates is often used as a treatment for acromioclavicular joint dislocation. However, it is not uncommon to find patients that have developed acromion osteolysis or had peri-implant fracture after hook plate fixation. With the aim of preventing complications or fixation failure caused by implantation of inappropriate clavicle hook plates, the present study investigated the biomechanics of clavicle hook plates made of different materials and with different hook depths in treating acromioclavicular joint dislocation, using finite element analysis (FEA). This study established four parts using computer models: the clavicle, acromion, clavicle hook plate, and screws, and these established models were used for FEA. Moreover, implantations of clavicle hook plates made of different materials (stainless steel and titanium alloy) and with different depths (12, 15, and 18 mm) in patients with acromioclavicular joint dislocation were simulated in the biomechanical analysis. The results indicate that deeper implantation of the clavicle hook plate reduces stress on the clavicle, and also reduces the force applied to the acromion by the clavicle hook plate. Even though a clavicle hook plate made of titanium alloy (a material with a lower Young's modulus) reduces the force applied to the acromion by the clavicle hook plate, slightly higher stress on the clavicle may occur. The results obtained in this study provide a better reference for orthopedic surgeons in choosing different clavicle hook plates for surgery.

Zoledronic acid-loaded bone cement as a local adjuvant therapy for giant cell tumor of the sacrum after intralesional curettage.

PURPOSE: Giant cell tumor of the sacrum is usually silent in initial stages and not diagnosed until achieving a large size. Intralesional curettage of the tumor has lower risk of neurological damage but is with high recurrence rate. Zoledronic acid-loaded cement was demonstrated to have cytotoxic effect on the cell line of giant cell tumor. This study evaluate if zoledronic acid-loaded bone cement would reduce the recurrence rate of sacral giant cell tumor after intralesional curettage. METHODS: Four patients were diagnosed as sacral giant cell tumor and received intralesional curettage with placement of zoledronic acid-loaded bone cement for adjuvant local control. The clinical records including tumor location, tumor size, complication, follow-up status, and functional outcome were analyzed retrospectively. RESULTS: All four patients presented with cauda equina syndrome before surgery with mean tumor volume of 472.8 cm(3). With placement of zoledronic acid-loaded cement, no local recurrence was observed during the mean follow-up period of 28 months. All patients were found to have new bone regeneration on radiograph. All patients suffering from cauda equina syndrome were recovered. CONCLUSIONS: We suggested that placement of zoledronic acid-loaded bone cement was an effective adjuvant therapy for sacral giant cell tumor following intralesional curettage.