Results and complications after removal of tibial tuberosity advancement cage for treatment of surgical site infections: A retrospective study

Preliminary Clinical and Radiographic Evaluation of a Novel Resorbable Implant of Polylactic Acid (PLA) for Tibial Tuberosity Advancement (TTA) by Modified Maquet Technique (MMT)

Our objectives were to determine whether PLA implants can be used in TTA with successful results; secondly, to observe whether they provide a faster bone healing; finally, to determine whether weight or age influences bone healing scores. PLA cages were created with a 3D printer. TTA by MMT with PLA implants was performed in 24 patients. Follow-ups were carried out pre-surgical, at 1, 2, and 5 months and consisted of a radiographic study and a lameness assessment. A comparison was performed in terms of weight and age. Patients data, time between follow-up examinations, healing score, and lameness score were compared between patients using commercial software for statistically significant differences p < 0.05. Eighteen dogs finished the study. The ossification degrees presented statistically significant differences between each other. PLA implants maintained the advancement in 100% of cases. Comparing weight and age did not present any statistically significant differences between groups. Lameness presented statistically significant differences between follow-up examinations. Complications were observed in 20.8%. PLA implants for TTA provide good functional results, presenting an acceptable rate of complications. They provide a faster bone healing of the osteotomy gap, which was not affected by age or body weight, and have a clinical recovery time similar to metallic implants.

Calcium sulfate antibiotic-impregnated bead implantation for deep surgical site infection associated with orthopedic surgery in small animals

OBJECTIVE

To report the outcomes and complications associated with antibiotic-impregnated calcium sulfate beads for prevention and treatment of orthopedic-related surgical site infection (SSI) in companion animals.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned cats (n = 2) and dogs (n = 14).

METHODS

Medical records of 16 cases in which implantation of antibiotic-impregnated calcium sulfate beads was performed for the prevention or treatment of SSI were reviewed. Information collected included signalment, prior surgery, reason for bead placement, antibiotics used, bacterial culture results, and clinical outcomes.

RESULTS

Surgical site infection resolved in six of 10 animals treated therapeutically and did not occur in six of six animals treated prophylactically. Susceptibility of the causative bacteria to the antibiotic implanted was confirmed in five of six cases with resolved SSI treated therapeutically but in only one of four cases with unresolved SSI treated therapeutically. Complications directly related to bead placement were evident in only one case in which beads extruded from external skeletal fixator pin tracts 7 days after implantation. At final follow-up, 11 of 12 animals without SSI had satisfactory limb use and no clinical, cytologic, or radiographic evidence of infection.

CONCLUSION

Implantation was well tolerated. Resolution of SSI was inconsistent; however, when bacteria were susceptible to the antibiotic implanted, SSI resolved in all but one case.

CLINICAL SIGNIFICANCE

Antibiotic-impregnated calcium sulfate beads could be considered for prevention or treatment of orthopedic SSI in small animals. A prospective clinical study is required to obtain additional information, including the value of preoperative bacterial culture.

Role of Tibial Tuberosity Fracture/Fissure through the Maquet Hole in Stifle Osteoarthritis after Porous Tibial Tuberosity Advancement in Dogs at Mid-Term Follow-Up

Tibial tuberosity advancement (TTA) is used to treat cranial cruciate ligament rupture of the stifle joint in dogs. Tibial tuberosity fracture/fissure is a complication of TTA that may have a favorable prognosis. The aim of this study was to detect how tibial tuberosity fracture/fissure through the Maquet hole worsens the progression of osteoarthritis (OA) in the stifle joint of dogs treated with porous TTA. Seventeen cases were included in the study, divided into two groups. The first group (n = 10) included subjects that had tibial tuberosity fracture/fissure through the Maquet, and the second group included subjects that had no complications (n = 7). Both groups showed significant progression compared to OA at 3 months after surgery. We observed that at T0, the control group showed a higher level of OA. For this reason, we normalized the OA scores, evaluating the percentage difference from T0 and T1. We verified that there were no statistically significant differences between the two groups. The results confirm that OA progression in subjects undergoing TTA was not significantly influenced by fracture/fissure of the tibial tuberosity through the Maquet hole. Therefore, fracture fissure through the Maquet hole should be considered as a common minor complication during TTA.

Biological response to an experimental implant for tibial tuberosity advancement in dogs: A pre-clinical study

In this study, we propose a novel bioresorbable bioactive implant for tibial tuberosity advancement (TTA). The implant consists of a gradually resorbing load-bearing shell which encompasses rapidly resorbing small casings loaded with silica-based bioactive glass (BG) particulates which promote bone formation and reduce the risk of infection. The shell and the casings are manufactured by 3D printing from two medical grade bioresorbable polymers (a polyglycolide/lactide based and a polydioxanone based) that have different degradation rates. The casings are expected to resorb within days after surgery to expose the BG particulates while the shell would retain the load-bearing properties of the implant for the time required by bone healing. Unlike the currently used metallic devices, the novel implant is resorbed and excreted from the body once its purpose is fulfilled. This study presents a logical progression from the in vitro characterisation of the materials and implants to the in vivo investigation of the experimental implants. This included mechanical testing of the materials, finite element analysis of a preliminary design of the novel TTA implant, assessment of the degradation behaviour of the polymers and the ion exchange of BG in simulated body fluid, and investigation of the biological response to the novel implants after implantation in rabbits. The osteointegration of the novel implants was comparable to the osteointegration of Ti6Al4V implants in the control group; the biological efficacy and safety were confirmed. The biological response was in line with the expectations. The proof of concept for the novel TTA implants was demonstrated.

Impact of postoperative antibiotics on rates of infection and implant removal after tibial tuberosity advancement in 1,768 canine stifles

OBJECTIVE

To report infection rate, implant removal rate, and postoperative antibiotic therapy after tibial tuberosity advancement (TTA) in dogs.

STUDY DESIGN

Retrospective study.

ANIMALS

One thousand seven hundred sixty-eight stifles in 1,732 dogs.

METHODS

Medical records (January 2007-December 2011) of dogs treated with a TTA were reviewed. Cases were included if at least 1 year of postoperative follow-up was available and no additional procedures were performed on the stifle. Date of surgery, date of culture, culture and susceptibility results, postoperative antimicrobials used, and any implant removals were recorded. Use of postoperative antibiotics and implant removal were evaluated statistically for effect on infection occurrence and resolution.

RESULTS

Postoperative infections were diagnosed in 82 of 1,768 (4.6%) stifles. Implants were removed from 32 (39%) stifles, with plate and screw removal only in 23 (71.9%) stifles. The rate of infection did not differ between dogs with or without postoperative antibiotic therapy. However, dogs receiving postoperative antibiotic therapy were at risk for developing an oxacillin-resistant infection (P = .001). Oxacillin-resistant infections were associated with a requirement for implant removal to achieve resolution compared with other types of bacterial infections (P < .05).

CONCLUSION

No benefit was detected with the use of postoperative antibiotics after TTA in this population. Implant removal was infrequent, and the requirement for cage removal was not commonly required for infection resolution.

CLINICAL SIGNIFICANCE

This study does not provide evidence to support postoperative antibiotic therapy after TTA. Postoperative infection can be treated in most dogs without removal of the TTA cage.