Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects.

PURPOSE: Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects. METHODS: This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason. RESULTS: Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components. CONCLUSION: Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Opening-wedge osteotomies of the distal femur: minor advantages for a biplanar compared to a uniplanar technique.

PURPOSE: Valgus malalignment of the distal femur may be treated with corrective osteotomy. The purpose of this study was to compare the primary stability of a lateral opening-wedge osteotomy (LOWO) using a uniplanar compared to a biplanar technique. A study was carried out to test both surgeries, with both an intact medial cortex and with a deliberate attached cut of the medial cortex simulating a fracture. The primary hypothesis was that the biplanar technique provides higher axial and torsional stiffness. It was further hypothesized that the mechanical superiority of the biplanar technique would not be affected in the case of breakage of the far medial cortex. METHODS: A LOWO was performed in ten synthetic femora (#3406 left large Femur, 4th Generation, Sawbones, Malmö, Sweden) using a lateral angle stable locking plate (NCB© Distal Femur Plate, Zimmer Biomet, Warsaw, USA). A uniplanar osteotomy was performed in five femora, and a biplanar osteotomy was performed in five femora. The femora were tested for axial and torsional loads using a servo-hydraulic testing machine (Instron 8874, Instron Structural Testing GmbH, High Wycombe, UK). RESULTS: Axial stiffness decreased significantly (p = 0.001) in both groups (20% in the uniplanar group and 28 % in the biplanar group) by cutting the medial cortex. The type of osteotomy had no significant effect. A slightly lower but not statistically significant axial stiffness was seen in the biplanar group both for intact and broken medial cortices. Internal torsional stiffness dropped by more than 30% for the uniplanar group and almost 24% for the biplanar group when the cortex was cut (p < 0.001). No significant change concerning internal torsional stiffness was found between the two groups. External torsional stiffness decreased by 32% for the uniplanar group and 4% for the biplanar group after the cortical cut (p = 0.029). No significant change concerning external torsional stiffness was found between the groups, but the biplanar group showed a tendency towards higher values of external torsional stiffness. CONCLUSIONS: The axial and torsional stiffness of the implant-bone construct were not significantly affected by the type of osteotomy performed. Biplanar osteotomy tended to increase external torsional stiffness. In cases of fracture of the medial cortex, biplanar osteotomy significantly reduced the external rotation at the osteotomy and showed a significantly increased external torsional stiffness.

Magnetic resonance evaluation in long term follow up of operated lateral tibial plateau fractures.

BACKGROUND: A lack of data exists on the long-term magnetic resonance imaging (MRI) findings after surgical repair of tibial plateau fractures (TPFs). We evaluated the MRI findings 13 to 31 years after surgical repair of TPFs, focusing especially on the pathological changes in the ligaments, menisci, and cartilage. METHODS: Twenty-three patients with 24 TPFs underwent open reduction and internal fixation with the same fork-shaped surgical plate that was used in our institution until 1999. No patient underwent preoperative or immediately postoperative MRI. The knees of all patients who underwent plate removal were examined by axial, coronal, and sagittal MRI. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and whole-organ magnetic resonance score (WORMS) were determined in all patients. RESULTS: All 24 knees exhibited MRI abnormalities. An unexpectedly high number of pathological changes in the menisci and ligaments were observed. No meniscal or ligamentous injuries were documented at the time of the injury or initial surgery, but meniscal injuries manifested in the long term. MRI in almost all cases showed a damage to the lateral meniscal, the severity of which was related to the degree of tibial plateau widening, but not to the severity of the lateral joint surface impression. The overall condition of the knee joint was satisfactory as measured by the WORMS, and there was a weak correlation between WORMS and KOOS.

Total knee arthroplasty with patient-specific instruments improves function and restores limb alignment in patients with extra-articular deformity.

BACKGROUND: Restoring function and alignment when treating knee arthritis with a total knee arthroplasty (TKA) in patients who have an extra-articular deformity (EAD) from a malunion or with retained femoral hardware is a challenge. The normal anatomical landmarks are hard to find and difficult to use to obtain correct alignment. The procedure will be further challenged by angular deformity of the femur or tibia. A retrospective study was performed on a case series of patients with EAD or obliteration of the canal treated with patient-specific instruments (PSI). METHODS: A multicenter retrospective review of 10 patients with multiplanar deformities in which the knee components were aligned with patient-specific instruments was performed. Outcome and alignment were studied. RESULTS: At a mean follow-up of 3.4years, function improved from preoperative as evidenced by a mean increase in the KS pain score of 53 points, KS function score of 48 points and Oxford Score of 28 points (P<0.05). Flexion improved from 94° +/- 11° to 112° +/- 15° (P<0.05). Limb alignment was restored with a mean Hip-Knee-Ankle angle of 179.3° +/- 1.3° (P<0.05). Maximum outliers were 177° to 181°. An average tourniquet time of 75 +/- 9minutes (range, 62-83min) was observed. CONCLUSIONS: The use of patient-specific instrumentation systems to perform TKA in patients without access to the intramedullary canal because of EAD or fixation devices, improved function and restored limb alignment. Mechanical alignment can easily be obtained with this technique by intra-articular correction of deformities under 20°. LEVEL OF EVIDENCE: Level IV.

Systematic analysis of painful total knee prosthesis, a diagnostic algorithm.

Remaining pain after total knee arthroplasty (TKA) is a common observation in about 20% of postoperative patients; where in about 60% of these knees require early revision surgery within five years. Obvious causes of this pain could be identified simply with clinical examinations and standard radiographs. However, unexplained painful TKA still remains a challenge for the surgeon. The management should include a multidisciplinary approach to the patient`s pain as well as addressing the underlying etiology. There are a number of extrinsic (tendinopathy, hip, ankle, spine, CRPS and so on) and intrinsic (infection, instability, malalignment, wear and so on) causes of painful knee replacement. On average, diagnosis takes more than 12 months and patients become very dissatisfied and some of them even acquire psychological problems. Hence, a systematic diagnostic algorithm might be helpful. This review article aims to act as a guide to the evaluation of patients with painful TKA described in 10 different steps. Furthermore, the preliminary results of a series of 100 consecutive cases will be discussed. Revision surgery was performed only in those cases with clear failure mechanism.

Early revision for isolated internal malrotation of the femoral component in total knee arthroplasty.

PURPOSE: In this prospective study, we determined whether corrective surgery for isolated rotational malalignment of femoral prosthesis components would benefit patients previously treated with total knee arthroplasty. The symptoms, amount of malrotation and type of constraint necessary for the revision prosthesis were investigated. METHODS: Seventy-two patients were screened with computed tomography; of these, 14 had isolated internal malrotation of the femoral component with no other malpositions and were included in the study. A complete exchange arthroplasty with the correction of the malrotated femoral component was performed within 3 years of primary arthroplasty. Mean follow-up was 57 months. RESULTS: At the time of revision, patients suffered either from instability in flexion with good range of motion (ROM) (flexion ≥ 90°) and pain on the lateral side of the distal femur and proximal tibia (n = 8) or from stiffness with pain on the medial side of the proximal tibial and poor ROM (flexion < 90°) (n = 6). One patient showed no patellar maltracking, six patients, patellar tilt and six patients, patellar subluxation. Median internal rotation of the femoral component was 7.1° (4.1-10.0°). A condylar-type revision implant with a posterior-stabilized insert was used in all patients. The corrective surgery resulted in an increase in the mean Knee Society Score from 52/65 to 85/84 points and an improvement in the mean Hospital for Special Surgery knee score from 63 to 83 points. CONCLUSIONS: Correction of isolated internal malrotation of the femoral component ≥ 4° improves patient outcome.

[Surgical treatment of knee joint osteoarthritis in the middle-aged patient]. / Gelenkerhaltende chirurgische Therapie der Gonarthrose im mittleren Lebensalter.

Several treatment options for the osteoarthritis of the knee in middle-aged patients to preserve the joint are available. Arthroscopic debridement is still a valuable treatment when detailed indications are considered. Microfracture procedure showed good and excellent results primarily at a follow-up of 2 years. Cartilage defects up to 4 cm2 should be treated by the mosaic-type osteochondral autologous transplantation. Autologous chondrocyte implantation (ACI) should be discussed when larger defects are presented in the younger patient. Existing osteoarthritis, ACI is not recommended. Up till now, there was no significant difference in outcomes comparing ACI and mosaicplasty or microfracture. Basic for successful surgical cartilage repair is a stable joint with a normal limb. An eventual additional osteotomy of the knee should be considered based on a standing, three-joint radiograph in every patient.

Treatment of deep infection of total knee arthroplasty using a two-stage procedure.

OBJECTIVE: Treatment of deep infection of total knee arthroplasty by two-stage reimplantation. Using an articulating spacer may reduce the disadvantages of a static spacer (ligament contracture, muscle atrophy, muscle contraction, arthrofibrosis, and bone loss). Restoration of pain-free loading and ability to walk. INDICATIONS: Late deep infection after total knee arthroplasty. DEFINITION: infection occurring at least 6 weeks after the initial arthroplasty. CONTRAINDICATIONS: Large metaphyseal bony defects of the distal femur and proximal tibia. Missing or insufficient extensor mechanism. SURGICAL TECHNIQUE: The articulating spacer is made intraoperatively by cleaning and autoclaving the explanted femoral component and the tibial polyethylene insert. These components are reinserted by "press-fit cementing" without cement interdigitation into the trabecular bone. The cement is loaded with antibiotic during the same operation (2-4 g antibiotics per 40 g of cement powder). POSTOPERATIVE MANAGEMENT: With the articulating spacer in place, partial weight bearing with crutches and continuous passive motion daily up to a flexion of 90 degrees are allowed. Usually, reimplantation with a standard revision system is scheduled for 6-12 weeks after spacer implantation. RESULTS: In a prospective study 33 consecutive patients were treated from February 2000 to July 2003. The average period of hospitalization after spacer implantation was 14 days (8-26 days). Three patients had recurrent infection (success rate 91%) after a mean follow-up period of 28 months (12-48 months). The average Hospital for Special Surgery Knee Score could be increased from 67 points (44-84 points) preoperatively to 87 points (53-97 points) after reimplantation. The complications were one temporary peroneal palsy, one dislocation of the spacer due to the absence of the extensor ligaments, and one fracture of the tibia due to substantial primary metaphyseal bone loss.

Absolute configuration of (-)-2,6-dimethyl-10-(p-tolyl)-2,6(E)-undecadiene from Cistus monspeliensis.

(-)-2,6-Dimethyl-10-(p-tolyl)-2,6(E)-undecadiene (1) is a major constituent in the essential oil of Cistus monspeliensis, an aromatic shrub common in Mediterranian countries. 1 was isolated by column chromatography, subjected to ozonolyses, and the absolute configuration was determined by enantioselective gas chromatographic correlation with the ozonolysis product of the sesquiterpene hydrocarbon ar-curcumene with known absolute configuration.