Treatment of 10-mm-Deep or Greater Uncontained Tibial Bone Defects in Primary Total Knee Reconstruction without Metal Augmentation: Autologous Oblique Structural Peg Bone and Cancellous Chip Bone Grafting.

BACKGROUD: In this study, we report satisfactory clinical and radiological outcomes after autologous oblique structural peg bone and cancellous chip bone grafting without metal augmentation, including the use of a metal wedge, block, or additional stem, for patients with ≥ 10-mm-deep uncontained medial proximal tibial bone defects in primary total knee replacement. METHODS: The study group included 40 patients with primary total knee replacement with ≥ 10-mm-deep uncontained tibial bone defects who underwent autologous oblique structural peg bone and cancellous chip bone grafting and were followed-up for at least 1 year. Tibial cutting was performed up to a depth of 10 mm from the articular surface of the lateral tibial condyle, after which the height and area of the remaining bone defect in the medial condyle were measured. The bone defect was treated by making a peg bone and chip bone using excised segments of the tibia and femur. In all cases, the standard tibial stem and full cemented fixation techniques were used without metal augmentation. Preoperative and final follow-up radiologic changes and clinical measures were compared, and prosthesis loosening and bone union were checked radiologically at final follow-up. RESULTS: The mean depth of the bone defects was 10.9 mm, and the mean percentage of the area occupied by bone defects in the axial plane was 18.4%. The mean mechanical femorotibial angle was corrected from 19.5° varus preoperatively to 0.2° varus postoperatively (p < 0.002). There was no prosthesis loosening, and all cases showed bone union at the 1-year postoperative follow-up. CONCLUSIONS: Even in patients with uncontained tibial bone defects ≥ 10-mm deep in primary total knee replacement, if the defect occupies less than 30% of the cut surface, autologous oblique structural peg bone and cancellous chip bone grafting can be used to achieve satisfactory outcomes with a standard tibial stem and no metal augmentation.

Microfractures Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial.

PURPOSE: The purpose of this study was to evaluate the clinical efficacy and safety of treating patients with a cartilage defect of the knee with microfractures and porcine-derived collagen-augmented chondrogenesis technique (C-ACT). METHODS: One hundred participants were randomly assigned to the control group (n = 48, microfracture) or the investigational group (n = 52, C-ACT). Clinical and magnetic resonance imaging (MRI) outcomes were assessed 12 and 24 months postoperatively for efficacy and adverse events. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) assessment was used to analyze cartilage tissue repair. MRI outcomes for 50% defect filling and repaired tissue/reference cartilage (RT/RC) ratio were quantified using T2 mapping. Clinical outcomes were assessed using the visual analogue scale (VAS) for pain and 20% improvement, minimal clinically important difference (MCID), and patient acceptable symptom state for Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee score. RESULTS: MOCART scores in the investigation group showed improved defect repair and filling (P = .0201), integration with the border zone (P = .0062), and effusion (P = .0079). MRI outcomes showed that the odds ratio (OR) for ≥50% defect filling at 12 months was statistically higher in the investigation group (OR 3.984, P = .0377). Moreover, the likelihood of the RT/RC OR becoming ≥1 was significantly higher (OR 11.37, P = .0126) in the investigation group. At 24 months postoperatively, the OR for the VAS 20% improvement rate was significantly higher in the investigational group (OR 2.808, P = .047). Twenty-three patients (52.3%) in the control group and 35 (77.8%) in the investigation group demonstrated more than the MCID of KOOS pain from baseline to 1 year postoperatively, with a significant difference between groups (P = .0116). CONCLUSION: In this multicenter randomized trial, the addition of C-ACT resulted in better filling of cartilage defect of the knee joint. LEVEL OF EVIDENCE: Level Ⅰ, Multicenter Randomized Controlled Trial.

Rotational alignment of femoral component for minimal medial collateral ligament release in total knee arthroplasty.

PURPOSE: We attempted to determine the degree of rotation of the femoral component to achieve an ideal rectangular flexion gap with minimal medial collateral ligament (MCL) release using a modified measured technique. MATERIALS AND METHODS: Group I consisted of 60 osteoarthritis patients (72 cases) who underwent total knee arthroplasty (TKA) with minimal MCL release and Group II consisted of 48 patients without osteoarthritis (61 cases). We performed computed tomography (CT) scanning of the knee with 90 degree flexion in all of the patients and analyzed the angles between the distal femur landmarks and the tibial mechanical axis using a Picture Archiving Communication system. External rotation of the femoral component from the Whiteside line and posterior condylar line was measured in group I who underwent TKA with minimum MCL release. The variance in the mediolateral flexion gap according to the degree of rotation was also measured using an Auto-Computer Aided Design program. RESULTS: The CT scans showed that the Whiteside line, posterior condylar line, and transepicondylar line was more internally rotated on average from the longitudinal axis of tibia by 4.12°, 5.54°, and 4.64°, respectively, in group I compared to group II. In group I, the femoral component was inserted with an average external rotation of 5.6° from the posterior condylar line and with an average external rotation of 2.0° from the Whiteside line with minimal MCL release. From the measurements of the femoral component size and the variance in the degree of rotation using an Auto-CAD program, it was found that the change in the mediolateral flexion gap was greater when the rotation angle was greater and it was greater when the size of femoral component was larger at the same rotation angle. CONCLUSIONS: The average rotation angle of the femoral component to achieve an ideal rectangular flexion gap with minimal MCL release in TKA was an external rotation of 5.6° from the posterior condylar line and an external rotation of 2.0° from the Whiteside line. We concluded that when a femoral component is small in size, greater than average external rotation needs to be applied and when a femoral component is large in size, less than average external rotation needs to be applied.

Hybrid stem fixation in revision total knee arthroplasty (TKA).

The purpose of this study was to retrospectively compare the clinical and radiographic results of the Maxim Posterior Stabilized Constrained (PCS) (Biomet Orthopaedics, Inc., Warsaw, IN, USA) knee system using the hybrid fixation versus the fully cemented fixation of stems of the same length. The cohort in this study included 115 knees in 104 patients, with a minimum 2-year follow up postoperatively. All patients were evaluated with the Knee Society clinical rating score and roentgenographic evaluation. Of the 115 revision total knee arthroplasty (TKA) cases, the hybrid-fixation technique was used on both the femoral and tibial components of 75 (Group I-hybrid femur, hybrid tibia); the fully cemented technique was used on both components of 24 (Group II-cemented femur, cemented tibia); the hybrid-fixation technique was used on the femoral component and full cement on the tibial component of 13 (Group III-hybrid femur, cemented tibia); the femoral component was fully cemented, and tibial component had the hybrid-fixation technique used on 3 (Group IV-cemented femur, hybrid tibia). The average follow up was 44 (range: 24-126) months. At the most recent evaluation, the Knee Society score improved from an average preoperative value of 51.7 to 76.7, the pain score improved from 14.0 to 33.3, and the functional score improved from 40.5 to 47.0. The average stem-to-canal fill ratio was 80% in the femur and 85% in the tibia (p<0.05). Stem-to-canal fill ratio did not appear to influence clinical outcome. Radiolucent lines less than 2 cm were observed more frequently in the hybrid-cemented stems (89%) than the fully cemented stems (58%) at an average 8-year follow up postoperatively (p<0.05). A lower, but not statistically significant, failure rate was observed in the hybrid group in comparison with the cemented group.