The Effect of Porous Tantalum Cones on Mechanical Alignment and Canal-Fill Ratio in Revision Total Knee Arthroplasty Performed with Uncemented Stems.

In revision total knee arthroplasty (TKA), the internal diameter of metal cones may limit the ability of the stem to properly fill the medullary canal. We prospectively studied 115 patients who underwent revision TKA with uncemented stems to evaluate the effect of metal cones on mechanical alignment and stem positioning. Correction on the mechanical alignment was well achieved in all patients, regardless of whether a metal cone was used. The proportion of patients achieving restoration of neutral mechanical alignment was similar between groups, as were the mean canal fill ratio (CFR) and the proportion of patients achieving CFR ≥ 85%. The use of porous tantalum cones in revision TKA with uncemented stems is not an obstacle in achieving optimal mechanical alignment and stem positioning.

Traffic in the operating room during joint replacement is a multidisciplinary problem.

BACKGROUND: Door openings disrupt the laminar air flow and increase the bacterial count in the operating room (OR). We aimed to define the incidence of door openings in the OR during primary total joint arthroplasty (TJA) surgeries and determine whether measures were needed and/or possible to reduce OR staff traffic. METHODS: We recorded the number of door openings during 100 primary elective TJA surgeries; the OR personnel were unaware of the observer's intention. Operating time was divided into the preincision period, defined as the time from the opening of surgical trays to skin incision, and the postincision period, defined as time from incision to dressing application. RESULTS: The mean number of door openings during primary TJA was 71.1 (range 35-176) with a mean operative time of 111.9 (range 53-220) minutes, for an average of 0.64 (range 0.36-1.05) door openings/min. Nursing staff were responsible for 52.2% of total door openings, followed by anesthesia staff at 23.9% and orthopedic staff at 12.7%. In the preincision period, we observed an average of 0.84 door openings/ min, with nursing and orthopedic personnel responsible for most of the door openings. The postincision period yielded an average of 0.54 door openings/min, with nursing and anesthesia personnel being responsible for most of the door openings. CONCLUSION: There is a high incidence of door openings during TJA. Because we observed a range in the number of door openings per surgery, we believe it is possible to reduce this number during TJA.

CONTEXTE: Les ouvertures de porte perturbent le flux laminaire et accroissent la numération bactérienne au bloc opératoire. Nous avons voulu mesurer l'incidence des ouvertures de porte au bloc opératoire durant les chirurgies pour prothèse articulaire totale (PAT) et déterminer si des correctifs étaient requis ou s'il était possible de réduire la circulation du personnel au bloc opératoire. MÉTHODES: Nous avons dénombré les ouvertures de porte durant 100 chirurgies électives primaires pour PAT; le personnel du bloc opératoire n'était pas au courant de l'intention de l'observateur. Le temps opératoire a été subdivisé en une période pré-incision, définie par l'intervalle entre l'ouverture des plateaux chirurgicaux et l'incision chirurgicale, et une période post-incision, définie par l'intervalle entre l'incision et l'application du pansement. RÉSULTATS: Le nombre moyen d'ouvertures de porte par intervention pour PAT primaire a été de 71,1 (entre 35 et 176) et la durée moyenne des interventions a été de 111,9 (entre 53 et 220) minutes, pour une moyenne de 0,65 (entre 0,36 et 1,05) ouverture/ minute. Le personnel infirmier était responsable de 52,2 % du nombre total d'ouvertures de porte, suivi du personnel d'anesthésie avec 23,9 % et du personnel d'orthopédie avec 12,7 %. Durant la période pré-incision, nous avons observé une moyenne de 0,84 ouverture de porte/minute, le personnel infirmier et d'orthopédie ayant été responsable de la majorité des ouvertures de porte. La période post-incision a donné lieu à une moyenne de 0,54 ouverture de porte/minute, le personnel infirmier et d'anesthésie ayant été responsable de la majorité des ouvertures de porte. CONCLUSION: On observe un nombre important d'ouvertures de porte durant les interventions pour PAT. Étant donné que ce nombre varie, nous croyons qu'il est possible de le réduire.

Internal rotation of the tibial component is frequent in stiff total knee arthroplasty.

BACKGROUND: Stiffness complicating TKA is a complex and multifactorial problem. We suspected internally rotated components compromised motion because of pain, patellar maltracking, a tight medial flexion gap, and limited femoral rollback on a conforming lateral tibial condyle. QUESTIONS/PURPOSES: We sought to determine: (1) the incidence of internal rotation of the femoral and tibial components in stiff TKAs; (2) if revision surgery that included correction of rotational positioning improved pain, ROM, and patellar tracking; and (3) if revision altered nonrotational radiographic parameters. METHODS: From a cohort of 52 patients with TKAs revised for stiffness, we performed CT scans of 34 before and 18 after revision to quantify rotational positioning of the femoral and tibial components using a previously validated scanning protocol. RESULTS: All 34 patients with TKAs had internal rotation of the summed values for tibial and femoral components (mean, 14.8°; range, 2.7°-33.7°) before revision for stiffness. The incidence of internal rotation was 24 of 34 femoral (mean, 3.1°; internal) and 33 of 34 tibial components (mean, 13.7° internal). Revision arthroplasty improved Knee Society function, knee, and pain scores. Mean extension improved from a contracture of 10.1° to 0.8° and flexion from 71.5° to 100°. Postrevision CT scans confirmed correction of component rotation. Nonrotational parameters were unchanged. CONCLUSIONS: We recommend CT scanning of patients with stiff TKAs before surgical intervention to identify the presence of internally rotated components. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Total knee arthroplasty with distal femoral replacement is associated with an important complication rate. A case series.

BACKGROUND: With the aging population and an increasing number of total knee arthroplasties (TKAs) performed yearly worldwide, revision surgeries for many causes (septic or aseptic loosening, periprosthetic femoral fractures (PDFF), non-unions, malunions) are more frequent and challenging. Distal femoral replacement (DFR) is sometimes the only option to restore knee function and quality of life. DFR in non-oncologic patient is still a rare indication and few reports are published on this topic, with a non-consistent variety of functional results, complication rates and survivorship. METHODS: We present a retrospective series of patients who underwent a DFR for a non-oncologic indication between 2010 and 2017. Nineteen patients were available for a full evaluation (clinical and radiological) with a mean follow-up of 48.3 months (range 15-99). Goniometry was performed at the six-week postoperative visit. Complications were reported. Osteolysis and/or signs of aseptic loosening were described using the Knee Society Radiographic Evaluation. Survivorship was calculated for aseptic loosening, infection, and revision for any cause. RESULTS: The mean Knee Society Score was good for the pain score (42.2, range 10-50) and fair for the function score (60.6, range 0-100). Four deep infections (21.1%) were successfully treated with mobile parts exchange and debridement. Three patients presented femoral osteolysis ≥5 years after the DFR. Survivorship for aseptic loosening was 100% at four years, 81.8% after five years and 53.3% after eight years. CONCLUSIONS: TKA with DFR is a valuable option for patients with a severe bone loss and poor bone quality in the distal femur. DFR restores an acceptable quality of life but is related to an important complication rate.

Up to seven years' follow-up of short cemented stems in complex primary total knee arthroplasty: A prospective study.

BACKGROUND: Although primary total knee arthroplasty (TKA) shows good clinical, functional and radiological results, it can be complicated by certain conditions or pathologies. The main objective of this study was to evaluate the global performance of short cemented metaphyseal stem components in patients undergoing complex primary TKA. METHODS: This is a single-surgeon prospective case series of 91 patients who underwent complex primary TKA requiring short stem fixation between January 2009 and October 2014. Knee Society Scores, physical examinations, and radiological assessments were performed pre- and postoperatively at six weeks, three months, six months, 12months, and annually thereafter. RESULTS: There were 40 females (46 TKAs) and 40 males (45 TKAs) in the study cohort. The left knee accounted for 52.7% of the surgeries. The average body-mass index (BMI) was 31.8kg/m2. Knee Society Scores obtained at the latest follow-up showed 96.4% and 95.5% good-to-excellent results respectively for the Knee and Function sub-scores. Radiological assessment showed that all Knee Society roentgenographic scores were below 10, without any evidence of impending or possible failure. Only one revision was required in this cohort for a patient suffering a deep chronic infection. At seven years, the Kaplan-Meier survivorship analysis revealed a 100% survivorship for aseptic loosening and a 98.9% survivorship for infection and revision of the components for any reason. CONCLUSION: This study demonstrated that TKA with short cemented stems resulted in good functional, clinical, and radiological outcomes for up to seven years for patients requiring complex TKA.

Instability of the proximal tibiofibular joint associated with total knee arthroplasty.

To our knowledge, proximal tibiofibular joint instability has never been reported in a patient with a total knee arthroplasty (TKA). We present the case of a patient with anterolateral proximal tibiofibular joint instability associated with a complex primary TKA. In 2010, a male patient of 47 years was referred for TKA after posttraumatic osteoarthritis. The patient's history includes a fracture of the left lateral tibial plateau in 2008 and removal of osteosynthesis material in 2009. TKA with a lateral metal augment and intramedullary stem was performed in 2010. After TKA, instability of the left proximal tibiofibular joint (PTFJ) was diagnosed. The patient underwent PTFJ arthrodesis and, at 5 years' follow-up, had no residual pain, with full range of motion. In this case, arthrodesis was the only possible surgical option because reconstruction surgeries require the establishment of bone tunnels in the tibia and fibula for the passage of a graft. Low bone quality and the use of an intramedullary stem with a metal augment in the tibia made any reconstruction technique unfeasible because the proximal tibia was obliterated. Although several PTFJ reconstruction techniques are available, they are difficult to apply to patients with a complex TKA.

Metabolic priorities during starvation: enzyme sparing in liver and white muscle of Atlantic cod, Gadus morhua L.

Atlantic cod, Gadus morhua, respond to starvation first by mobilising hepatic lipids, then muscle and hepatic glycogen and finally muscle proteins. The dual role of proteins as functional elements and energetic reserves should lead to a temporal hierarchy of mobilisation where the nature of a function dictates its conservation during starvation. We examined (1) whether lysosomal and anti-oxidant enzymes in liver and white muscle are spared during prolonged starvation, (2) whether the responses of these enzymes in muscle vary longitudinally. Hepatic contents of lysosomal proteases decreased with starvation, whereas those of catalase (CAT) increased and lysosomal enzymes of carbohydrate metabolism and glutathione S-transferase (GST) did not change. In white muscle, starvation decreased the specific activity of lysosomal enzymes of carbohydrate degradation and doubled that of cathepsin D (CaD). The activity of anti-oxidant enzymes and acid phosphatase in muscle was unchanged with starvation. In white muscle neither lysosomal enzymes nor anti-oxidant enzymes varied significantly with sampling position. In cod muscle, antioxidant enzymes, CaD and acid phosphatase are spared during a period of starvation that decreases lysosomal enzymes of carbohydrate metabolism and decreases glycolytic enzyme activities. In cod liver, the anti-oxidant enzymes, CAT and GST, were also spared during starvation.