No higher tibial post fracture rate with highly cross-linked polyethylene inserts in total knee arthroplasty at a minimum 10-year follow-up.

PURPOSE: The purpose of this study was to assess tibial post fracture between highly cross-linked polyethylene (HXPE) and conventional polyethylene inserts in consecutive posterior-stabilized (PS) total knee arthroplasty (TKA) over a minimum 10-years follow-up period. METHODS: Between July 2008 and December 2011, a consecutive series of 3264 primary TKAs was performed in 2098 patients using a PS total knee prosthesis at a single institution. The final cohort was classified into the HXPE group (792 cases) and the conventional group (2113 cases) according to insert material used during the procedure. RESULTS: The mean follow-up period was 11.4 years in the HXPE group and 11.8 years in the conventional group. Both cases of tibial post fracture occurred in the HXPE group, a complication rate of 0.25%. These two cases required replacement with a thicker tibial insert with retention of the femoral and tibial components. There were no cases of tibial post fracture in the conventional group. CONCLUSION: There was no difference in tibial post fracture rate between the HXPE group and the conventional group in PS TKA on long-term follow-up. LEVEL OF EVIDENCE: IV.

High rate of tibial post-fracture in highly cross-linked polyethylene compared to conventional polyethylene in posterior-stabilized total knee arthroplasty at a minimum 12-year follow-up.

PURPOSE: The purpose of this study was to assess tibial post-fracture between highly cross-linked polyethylene (HXPE) and conventional polyethylene inserts in consecutive posterior-stabilized (PS) total knee arthroplasty (TKA) over a minimum 12-year follow-up period. METHODS: Between January 2007 and June 2008, a consecutive series of 2446 primary TKAs was performed in 1478 patients at a single institution. The final cohort was classified into two groups (1559 in the HXPE group and 887 in the conventional group) based on the insert material used during the procedure. RESULTS: The mean follow-up period was 13.1 years in the HXPE group and 13.4 years in the conventional group. All 16 cases of tibial post-fracture occurred in the HXPE group. This complication rate was 1.03%. The mean elapsed time from primary TKA to the diagnosis of post-fracture was 3.9 years (range 0.5-10.0 years). Ten cases required replacement with a thicker polyethylene insert, and six cases underwent tibial revision surgery. There were no cases of tibial post-fracture in the conventional group. CONCLUSION: Tibial post-fracture is not a rare complication in PS TKA with HXPE. Therefore, the possibility of a tibial post-fracture should be considered if newly developed pain, acute subluxation, effusion, patellar clunking, or instability occurs in patients treated with PS Scorpio knee system TKA using an HXPE insert. LEVEL OF EVIDENCE: IV.

Patellar Impingement on Tibial Polyethylene after Primary Total Knee Arthroplasty without Patellar Resurfacing.

Patellar impingement on tibial polyethylene (PIP) is one potential complication of total knee arthroplasty (TKA). When PIP occurs, it is often related to inaccurate restoration of the joint line or due to soft-tissue contracture. We investigated the prevalence and etiology of PIP in Asian patients with deeply flexed knees following posterior stabilized (PS)-TKA. We retrospectively reviewed 54 patients (65 knees) with PIP after primary PS-TKAs without patellar resurfacing performed between 2008 and 2011. These patients were compared with a group of 124 patients (130 knees) without PIP matched for age, sex, and body mass index (BMI). The minimum follow-up was 5 years (range, 5-8.1 years). Patients were evaluated by blinded, independent observers using the Oxford knee score, the Waters score, and radiographic parameters. Impingement between the patella and the tibial polyethylene had a mean onset of 13.5 months after PS-TKA. The development of PIP was significantly associated with change in patellar tendon length (odds ratio [OR] = 11.4, 95% confidence interval [CI]: 11.2-11.6%), shorter postoperative patellar tendon length (OR = 2.1, 95% CI: 1.8-2.5%), change in the Insall-Salvati ratio (OR = 0.9, 95% CI: 0.8-1.0%), and joint line elevation (OR = 5.3, 95% CI: 4.8-5.8%) on multiple logistic regression analysis. Our findings reinforce the importance of accurate joint line restoration and the avoidance of iatrogenic injury to the patellar tendon, which can lead to shortening of the patellar tendon. This is a retrospective comparative study and its level of evidence is III.

Dural Tears in Percutaneous Biportal Endoscopic Spine Surgery: Anatomical Location and Management.

OBJECTIVE: To determine the rate and anatomical location of dural tears associated with spinal surgery using a percutaneous biportal endoscopic surgery (PBES) technique. We investigated the relationship between dural tears and the type of procedure and type of instrument used. METHODS: We retrospectively analyzed 643 PBES cases by reviewing the medical records, operative records, and operative videos. Incidental durotomy was identified in 29 cases. We analyzed the size and anatomical location of the dural tears, the surgical instrument that caused the tear, and the technique used to seal the tear. RESULTS: The dural tear incidence was 4.5% (29 of 643 cases). Tears in the exiting nerve area (2 cases; 6.9%) had mainly been caused by curettage, tears in the thecal sac area (18 cases; 62.1%) were associated with electric drill and forceps use; and tears in the traversing nerve area were associated with the use of a Kerrison punch (9 cases; 31%). Of the 29 cases of dural tear, 12 were treated with in-hospital monitoring and bed rest, 14 were treated with a fibrin sealant, 2 were treated with a nonpenetrating titanium clip, and 1 was converted to microscopic surgery. One case of postoperative meningocele after conservative treatment required endoscopic revision surgery to close the dural tear. CONCLUSIONS: Most cases of incidental dural tear during PBES were treated with an endoscopic procedure. The incidence of dural tear was no greater than that associated with microscopic surgery. Our management strategy for incidental dural tears during PBES has been shown to be safe and effective.

Fractured polyethylene tibial post in a posterior-stabilized knee prosthesis presenting as a floating palpable mass.

Complications associated with posterior-stabilized total knee arthroplasty (TKA) include patellar clunk syndrome, posterior subluxation of the tibial component, tibial post wear, and tibial post failure. Recently, an increasing number of reports have been issued on polyethylene tibial post failure in posterior-stabilized TKA. In most of these cases, tibial post failure in a well-functioning posterior-stabilized TKA was suspected based on clinical symptoms, such as a sudden onset of pain, effusion, patellar clunking, knee instability, and prosthesis dislocation. However, a floating, palpable, hard, mass-like symptom in the knee joint has not been previously reported. The authors report a case of a fractured polyethylene tibial post in a posterior-stabilized TKA that manifested as a palpable mass in the suprapatellar pouch.

Lateral meniscus and lateral femoral condyle cartilage injury by retained cement after medial unicondylar knee arthroplasty.

The authors experienced an unusual case of a patient with a complex tear of the lateral meniscus and adjacent lateral femoral condyle cartilage injury in the contralateral compartment by retained cement, possibly located at the posteromedial side of the medial tibial component after unicondylar knee arthroplasty. Arthroscopic partial meniscectomy and cartilage microfracture were successfully performed. Two small cement fragments were removed from the posterolateral compartment. A sharp pain in the lateral side disappeared postoperatively and posterior knee pain was much reduced.

Polymer micelle formulation for the proteasome inhibitor drug carfilzomib: Anticancer efficacy and pharmacokinetic studies in mice.

Carfilzomib (CFZ) is a peptide epoxyketone proteasome inhibitor approved for the treatment of multiple myeloma (MM). Despite the remarkable efficacy of CFZ against MM, the clinical trials in patients with solid cancers yielded rather disappointing results with minimal clinical benefits. Rapid degradation of CFZ in vivo and its poor penetration to tumor sites are considered to be major factors limiting its efficacy against solid cancers. We previously reported that polymer micelles (PMs) composed of biodegradable block copolymers poly(ethylene glycol) (PEG) and poly(caprolactone) (PCL) can improve the metabolic stability of CFZ in vitro. Here, we prepared the CFZ-loaded PM, PEG-PCL-deoxycholic acid (CFZ-PM) and assessed its in vivo anticancer efficacy and pharmacokinetic profiles. Despite in vitro metabolic protection of CFZ, CFZ-PM did not display in vivo anticancer efficacy in mice bearing human lung cancer xenograft (H460) superior to that of the clinically used cyclodextrin-based CFZ (CFZ-CD) formulation. The plasma pharmacokinetic profiles of CFZ-PM were also comparable to those of CFZ-CD and the residual tumors that persisted in xenograft mice receiving CFZ-PM displayed an incomplete proteasome inhibition. In summary, our results showed that despite its favorable in vitro performances, the current CFZ-PM formulation did not improve in vivo anticancer efficacy and accessibility of active CFZ to solid cancer tissues over CFZ-CD. Careful consideration of the current results and potential confounding factors may provide valuable insights into the future efforts to validate the potential of CFZ-based therapy for solid cancer and to develop effective CFZ delivery strategies that can be used to treat solid cancers.

Graphene-Iodine Nanocomposites: Highly Potent Bacterial Inhibitors that are Bio-compatible with Human Cells.

Graphene-composites, capable of inhibiting bacterial growth which is also bio-compatible with human cells have been highly sought after. Here we report for the first time the preparation of new graphene-iodine nano-composites via electrostatic interactions between positively charged graphene derivatives and triiodide anions. The resulting composites were characterized by X-ray photoemission spectroscopy, UV-spectroscopy, Raman spectroscopy and Scanning electron microscopy. The antibacterial potential of these graphene-iodine composites against Klebsiella pneumonia, Pseudomonas aeruginosa, Proteus mirobilis, Staphylococcus aureus, and E. coli was investigated. In addition, the cytotoxicity of the nanocomposite with human cells [human white blood cells (WBC), HeLa, MDA-MB-231, Fibroblast (primary human keratinocyte) and Keratinocyte (immortalized fibroblast)], was assessed. DGO (Double-oxidizes graphene oxide) was prepared by the additional oxidation of GO (graphene oxide). This generates more oxygen containing functional groups that can readily trap more H(+), thus generating a positively charged surface area under highly acidic conditions. This step allowed bonding with a greater number of anionic triiodides and generated the most potent antibacterial agent among graphene-iodine and as-made povidone-iodine (PVP-I) composites also exhibited nontoxic to human cells culture. Thus, these nano-composites can be used to inhibit the growth of various bacterial species. Importantly, they are also very low-cytotoxic to human cells culture.