Mapping bacterial biofilm on explanted orthopedic hardware: An analysis of 14 consecutive cases.

Hardware implanted during primary total joint arthroplasty carries a serious risk for periprosthetic joint infection (PJI). The formation of bacterial biofilms, which are highly tolerant of antibiotics and host immunity, is recognized as being a major barrier to treatment. It is not known whether some components and their surface features are more prone to biofilm than others. This study attempted to map biofilm on different components and features of orthopedic hardware recovered during revision. Implant surface culture (ISC) was used on 53 components from 14 hip and knee revisions. ISC achieves a thin agar coating over components, followed by incubation and observation for colony outgrowth over 9 days. Recovered organisms were identified by selective culture and 16s rRNA sequencing. Outcomes were compared with clinical culturing and PJI diagnosis based on 2013 Musculoskeletal Infection Society criteria. ISC paralleled clinical culturing with a sensitivity of 100% and a specificity of 57.1%. When compared to Musculoskeletal Infection Society criteria, sensitivity remained at 100% while specificity was 80%. Biofilm accumulation was patchy and heterogeneous throughout different prostheses, though notably the non-articulating surfaces between the tibial tray and polyethylene insert showed consistent growth. On individual components, ridges and edges consistently harbored biofilm, while growth elsewhere was case dependent. ISC successfully identified microbial growth with high sensitivity while also revealing that biofilm growth was commonly localized to particular locations. Understanding where biofilm formation occurs most often on implanted hardware will help guide debridement, retention choices, and implant design.

Medial Osteoarthritis in an ACL-Deficient Knee: A Critical Analysis Review.

¼: In anterior cruciate ligament (ACL)-deficient knees, treatment of medial compartment osteoarthritis (OA) that is refractory to nonoperative modalities is a controversial subject. ¼: Currently available treatment options include unicompartmental knee arthroplasty (UKA) with or without ACL reconstruction (ACLR), high tibial osteotomy (HTO) with or without ACLR, and total knee arthroplasty (TKA). ¼: Each treatment option has its own risks and benefits, and the evidence that is reviewed in this article suggests that patient characteristics guide treatment selection. ¼: Future high-quality prospective studies that directly compare all 3 of the modalities are necessary to determine the best treatment option for different patient populations.

Cerclage wires or cables for the management of intraoperative fracture associated with a cementless, tapered femoral prosthesis: results at 2 to 16 years.

Initial stability is critical for fixation and survival of cementless total hip arthroplasty. Occasionally, a split of the calcar occurs intraoperatively. A review of 1,320 primary total hip arthroplasties with 2-year follow-up, performed between August 1985 and February 2001 using the Mallory-Head Porous tapered femoral component, revealed 58 hips in 55 patients with an intraoperative calcar fracture managed with single or multiple cerclage wires or cables and immediate full weight bearing. At 7.5 years average follow-up (range, 2-16 years), there were no revisions of the femoral component, radiographic failures, or patients with severe thigh pain, for a stem survival rate of 100%. Average Harris hip score improvement was 33.8 points. Fracture of the proximal femur occurs in approximately 4% of primary THAs using the Mallory-Head Porous femoral component. When managed intraoperatively with cerclage wire or cable, the mid- to long-term results appear unaffected with 100% femoral component survival at up to 16 years.

Patella baja and total knee arthroplasty (TKA): etiology, diagnosis, and management.

Patella baja, that can be divided into congenital, acquired, or a combination of the two, is commonly encountered in total knee arthroplasty (TKA). Congenital patella baja refers to a patella distal in relationship to the femoral trochlea and present since an early age. Acquired patella baja may occur secondary to distal positioning of the patella relative to the femoral trochlea or shortening of the patellar tendon, as a result of trauma or surgery. Patella baja also can occur postoperatively as a result of scarring and shortening of the patellar tendon, scarring of the patellar tendon to the anterior aspect of the tibia, or both. Another cause of acquired patella baja seen commonly in TKA is elevation of the joint line, referred to as pseudo-patella baja. The patella remains in a normal position relative to the femoral trochlea; however, the distance between the patella and tibia is narrowed. Pseudo-patella baja can be a result of tibial or femoral over-resection, which necessitates a large polyethylene insert. Alterations of the patello-tibial distance can occur during TKA by excessive soft-tissue release that requires elevation of the joint to regain stability and placement of the patellar polyethylene component distally on the patella. Prevention is the easiest way to avoid potential problems with patella baja during TKA; however, the surgeon is often confronted with this situation during total knee revisions. Failure to address patella baja can lead to decreased range of motion (ROM), a decreased lever arm, extensor lag, impingement of the patella against the tibial polyethylene or tibial plate, anterior knee pain, increased energy expenditure, and rupture of the patellar or quadriceps tendons. Treatment of patella baja first depends on determining the cause and distinguishing between patella baja and pseudo-patella baja. Five different methods to measure patella baja are reviewed and include: (1) Blumensaat's line, (2) Insall-Salvati ratio, (3) Modified Insall-Salvati ratio, (4) Blackburne-Peel, and (5) Caton-Deschamps. Corrective measures include reestablishing the joint line by use of distal femoral augments, tibial tubercle osteotomy with proximal displacement, lengthening of the patellar tendon, shaving of the anterior portion of the tibial polyethylene, and placement of the patellar implant in a cephalad position.