Knee arthrodesis as last resort for persistent knee joint infections : Comparison of extramedullary and intramedullary treatment

A retrospective claims data analysis of health care utilization and cost among patients receiving multi-injection intraarticular hyaluronic acid

BACKGROUND

With the rising costs for knee arthroplasty, therapies that allow patients to avoid or delay surgery following knee osteoarthritis (KOA) may help in reducing overall health care costs. Multiple intraarticular hyaluronic acid (HA) products are available on the market, varying by formulation, molecular weight, and number of injections, but clinical and economic benefits may differ by product. OBJECTIVES: To evaluate the all-cause and KOA-related health care resource utilization (HCRU) and costs among newly diagnosed patients with KOA treated with multi-injection HA.

METHODS

A retrospective cohort study using a large commercial claims database (Merative MarketScan database) to identify patients with KOA treated with high molecular weight (HMW) (n = 11,200), medium molecular weight (MMW) (n = 10,225), or low molecular weight (LMW) HAs (n = 8,473) between 2016 and 2019. KOA-related and all-cause HCRU and costs were compared within 12 months after the index HA treatment date. The association between outcomes and HA treatments was evaluated using a doubly robust method to adjust for confounding factors. HCRU and costs among the propensity score-weighted HA groups were compared using generalized linear models.

RESULTS

HMW HA patients were found to have lower adjusted KOA-related medical costs by $265.37 (P < 0.001) and pharmacy costs by $19.90 (P < 0.001) compared with LMW HA patients, as well as lower all-cause total medical costs by $130.42 (P = 0.013) and pharmacy costs by $63.33 (P < 0.001). HMW HA patients also had a lower adjusted KOA-related medical cost by $205.74 (P < 0.001) and pharmacy cost by $14.39 (P < 0.001) compared with MMW HA patients, as well as lower all-cause medical by $1,195.66 (P < 0.001) and pharmacy by $196.99 (P < 0.001). Three-injection treatment patients (HMW HA, 84%; MMW HA, 82%) had high completion rate, compared with the 5-injection treatment cohort (LMW HA, 48%).

CONCLUSIONS

HMW HA patients had statistically significantly lower adjusted all-cause and KOA-related medical and pharmacy costs at 1 year follow-up compared with MMW HA and LMW HA patients. It is unclear if this is related to differences in molecular weight or specific mechanism of actions.

Knee Arthrodesis for Periprosthetic Knee Infection: Fusion Rate, Complications, and Limb Salvage-A Systematic Review

The aim of this systematic review was to investigate the outcomes of knee arthrodesis (KA) after periprosthetic joint infection (PJI) of the knee. Differences in clinical outcomes and complication rates among the intramedullary nailing (IMN), external fixation (EF), and compression plating (CP) procedures were compared. A total of 23 studies were included. Demographics, microbiological data, types of implants, surgical techniques with complications, reoperations, fusion, and amputation rates were reported. A total of 787 patients were evaluated, of whom 601 (76.4%), 166 (21%), and 19 (2.4%) underwent IMN, EF, and CP, respectively. The most common causative pathogen was coagulase-negative Staphylococcus (CNS). Fusion occurred in 71.9%, 78.8%, and 92.3% of the patients after IMN, EF, and CP, respectively, and no statistically significant difference was found. Reinfection rates were 14.6%, 15.1%, and 10.5% after IMN, EF, and CP, respectively, and no statistically significant difference was found. Conversion to amputation occurred in 4.3%, 5%, and 15.8% of patients after IMN, EF, and CP, respectively; there was a higher rate after CP than after EF. The IMN technique is the most common option used for managing PJI with KA. No differences in terms of fusion, reinfection, or conversion-to-amputation rates were reported between IMN and EF. CP is rarely used, and the high amputation rate represents an important limitation of this technique.

Prosthetic Knee Joint Infection Due to Candida lusitaniae: A Diagnostic and Therapeutic Odyssey: A Case Study

Prosthetic joint infections (PJIs) caused by fungi, although relatively rare, represent a major surgery-related complication. An extremely rare fungal PJI, following revised total knee replacement (TKR) caused by Candida lusitaniae, is reported, and a meticulous review of similar cases is provided. A 74-year-old female, who underwent primary total knee arthroplasty 10 years ago and a revision surgery three weeks ago, presented with signs and symptoms of PJI. C. lusitaniae was eventually isolated from the periprosthetic tissue using the MALDI-TOF VitekMS-bioMérieux technique. Multiple strategies for managing this fungal PJI were performed, and finally, the patient was treated successfully with an intramedullary arthrodesis system and proper antifungal treatment, including fluconazole. A multidisciplinary approach is essential for the diagnosis and treatment of such severe infections. In persistent cases and in cases where revision surgery is extremely difficult to perform, arthrodesis seems to be an effective solution for the elimination of the infection. The efficacy of the therapeutic management of fungal PJIs remains unclear. Therefore, more research should be reported, focusing on proper treatment so that the optimal strategy in treating these severe infections may be established.

Low complication rate and better results for intramedullary nail - arthrodesis for infected knee joints compared to external fixator-a series of one hundred fifty two patients

PURPOSE

Arthrodesis of the knee joint is still a salvage procedure after recurrent prosthetic joint infections (PJI) of total knee arthroplasties (TKA) with substantial bone loss and seems to be a good solution to avoid amputation. Until now, intramedullary arthrodesis has increasingly been performed; no study has yet been published to compare these techniques after septic removal of TKA in terms of functional assessment and quality of daily life.

METHODS

In a single-centre retrospective setting, clinical and radiographic evaluation of consecutive patients after knee arthrodesis using intramedullary and external fixation for infected knee joints was performed. All patients were evaluated clinically, with x-ray and questionnaire including analysis regarding any complications at latest follow-up of a minimum 12 months postoperatively.

RESULTS

We included 152 patients (75 females, 77 males) in this study. The mean age of the patients at surgery was 63.6 years (range 12 to 90 years). The minimum follow-up was 12 months (mean 3.1 years, range 12 to 49 months). Arthrodesis with external fixator (83 patients, 52.2%) showed less blood loss and less peri-operative complications (1.6%) but a high rate of post-operative, pin-track infections (35.5%); loose pins (12.7%); and pin fractures (4.8%), and therefore risk factors for instability and nonunion (30.9%). Revision rate was 22.6% for arthrodesis with external fixator, and the primary union rate was 65.6%. Intramedullary arthrodesis (69 patients, 43.4%) showed a similar re-infection rate to external fixation (16.1% and 15.9%, respectively) but a significantly lower revision rate (5.4%, p < 0.001). Eighty percent of patients with intramedullary arthrodesis showed very good patient-related outcomes regarding pain, function and daily life activities in the questionnaire.

CONCLUSION

Despite similar results regarding patient satisfaction and everyday competences in questionnaires, intramedullary arthrodesis of the knee is superior to the external fixator, as it results in fewer complications, lower revision rate, and union rates/loosening.