Background. Total knee arthroplasty (TKA) is the highly developed procedure for sever osteoarthritic knee, in which there are two major concepts; Cruciate Retaining design (CR) and Posterior Stabilized design (PS). The femoral roll back movement is enforced with the post-cam mechanism in the PS, however, this structure associates with the complications, i.e. wear and dislocation. The CR has been developed to obtain the knee stability with native posterior cruciate ligament (PCL) in TKA. However, the preservation of the PCL can limit knee exposure and increase the technical challenge of surgery. We hypothesized that the knee exposure was easily achieved after the PCL was released, however, the PCL was repaired and the posterior stability was re-established after the TKA with time if it was released subperiostealy. Objective. The objective of this study was to evaluate the varying of the posterior stability after the PCL-released CR TKA. Methods. Patients were performed the CR TKA with 3DKnee (DJO Global, Vista, CA), in which the entire PCL was subperiostealy released at its femoral insertion (Fig. 1). Following that, the patients were examined with the Knee Society Score and the KT-2000 knee ligament arthrometer (MedMetric Corp., San Diego, CA) firstly between 3 weeks and 7 weeks and secondly between 12 weeks and 20 weeks postoperatively. Results. There were 8 cases in 2 female and 6 male knees, and the age was 63.3 ± 11.1 (ranging from 51 to 79). Once the PCL was released, the tibia was easy to subluxate, and the knee was clearly exposed intraoperatively. The Knee Society knee score at the first evaluation was 74.4 ± 10.7 (59 to 90), which was significantly improved compared to the preoperative score of 37.0 ± 9.4 (25 to 50) (p<0.001). Then, the score increased up to 89.4 ± 11.6 (70 to 100) at the second evaluation. The function score was 35.6 ± 19.9 (5 to 55) preoperatively and decreased to 24.4 ± 12.2 (20 to 55) at the first evaluation. After that, it increased to 82.5 ± 14.1 (65 to 100) (p<0.001) at the second evaluation. The anteroposterior laxity was 5.2 ± 1.9 (3 to 7.5) mm at the first evaluation, and was improved to 3.6 ± 1.2 (2 to 5) mm (p<0.046). Therefore, the posterior stability was confirmed to be re-established. We also confirmed the re-establishment of the PCL integrity at a revision TKA, in which the original procedure had been performed 7 years ago (Fig. 2). Conclusion. The re-establishment of the posterior stability after the PCL-released CR TKA was demonstrated. This procedure to release the entire PCL subperiostealy is recommended as a means of facilitating CR TKA

Aims

No predictive model has been published to forecast operating time for total knee arthroplasty (TKA). The aims of this study were to design and validate a predictive model to estimate operating time for robotic-assisted TKA based on demographic data, and evaluate the added predictive power of CT scan-based predictors and their impact on the accuracy of the predictive model.

Aims

Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.

Our aim was to evaluate the functional outcome of extensile revision knee exposure techniques. 166 revision total knee arthroplasties requiring an extensile exposure with 2 year minimum follow-up were prospectively studied {81 rectus snips (RS), 42 tibial tubercle osteotomies (TTO), and 43 quadriceps turn-downs (QT)}. Patients were clinically evaluated for knee society score, range of motion (ROM) and extensor lag comparing pre-op and 24 month follow-up appointment findings. Radiological evidence of avascular necrosis (AVN) pre & post operation was recorded. The TTO group was further examined for proximal migration of the tubercle post op. Pre-operative knee motion (75° & 71°) and knee scores (74 & 70) were lower in revision total knee arthroplasties requiring QT & TTO than those requiring a RS (91° & 84). Post op flexion and knee scores were greater in the RS group (102° & 131) than in the QT (81° & 114) and TTO (84° & 111) groups in whom there was no significant difference. Avascular necrosis of the patella was most commonly seen following QT. In both QT & TTO groups performing a lateral release was significantly associated with AVN of the patella. Extensor lag (> 10°) was seen only in the QT & TTO groups (11% & 8%) in whom there was no significant difference. Tubercle escape (> 2mm) in the TTO group was significantly greater (54%) in those where circlage wires only had been used than in those where a proximal transfixation wire was used (11%). In conclusion, both QT & TTO groups had similarly poor knee scores & ROM pre & post operation. AVN of the patella for both groups was similar and significantly associated with performing a lateral release. Finally we would conclude that the use of a through wire significantly reduces tubercle escape in TTO fixation

The aim of the study was to investigate rotational behaviour of the arthritic knee before (preimplant) and after (postimplant) total knee replacement (TKR) using (image-free navigation system as a measurement tool which recorded the axial plane alignment between femur and tibia, in addition to the coronal and sagittal alignment as the knee is flexed through the range of motion. The data on the rotation of the arthritic knee was collected after the knee exposure and registration of the lower limb (preimplant data). The position of rotation between the femur and tibia was recorded in 30° flexion, 45°, 60°, 90° and maximum degrees of flexion of the knee. The data was divided into subsets of varus and valgus knees and these were analysed pre and postimplant for their rotational position using SPSS for statistics. The system was used in 117 knees of which 91 had full data set available (43 male 48 female). These included 71 varus knees, 16 valgus knees and 4 neutral knees to start in extension. Preimplant data analysis revealed there is tendency for the arthritic knees to first go in internal rotation in the initial part of flexion to 30 degrees and then the rotation is reversed back. This happens irrespective of the initial starting rotational relationship between femur and tibia in full extension. This happens in both varus as well as valgus arthritic knees. This trend of internal rotation in this initial part of flexion is followed in TKR as well implanted with fixed bearing CR knees irrespective of the preoperative deformity. Also noteworthy was the difference in rotation at 30°, 60° and 90 degrees of flexion between preimplant and postimplant knees (irrespective of varus and valgus groups). When calculated at different points of flexion, there was statistically significant difference in the change of rotation at each point of flexion except 45 degree of flexion. The pre-operative values of change in rotation (internal being positive) at each step from the extended position being 5.4° (SD 4.5°) at 30 ° flexion, 4.7°(5.2°) at 45°, 3.6°(6.1°) at 60°, 3.5°(7.2°) at 90° and 4.2°(8.3°) at maximum flexion. Corresponding post-operative rotations were 2.2°(4.8°), 4.1°(6.4°), 6.6°(7.3°), 9.9°(8.8°) and 7.7°(8.9°). There was also an increase in the total range of rotation that the knee goes through after it has been implanted with prosthesis although it may not happen in every knee. This is statistically significant (p value <0.001) and seems more so in valgus group. The rotational movements and interrelationship of the femur and tibia is a complex issue, especially in the arthritic knees. Preimplant arthritic knee behaved generally similarly to normal knees according to the literature. Normal gait pattern demonstrates that the tibia moved through a 4° to 8° arc of internal rotation relative to the femur. The overall range (10.2° =/−4.2°) of knee rotation in this study greater than 8° might be explained by preimplant data acquired after the knee was approached and therefore releasing knee soft tissue envelop. This study confirmed that during the first 30° both varus and valgus knees moved internally. In our study there is increased range of total rotation postimplant (14° =/−6.8°) which may be explained by the fact that the anterior cruciate ligament is lost in all the TKRs and the posterior cruciate ligament may be dysfunctional as well. Thus the constraints on the knee rotation are decreased postimplant leading to increased rotation. We found some difference between varus and valgus post implant knees in that internal rotation seen in initial 30 degrees of flexion is much more pronounced in valgus knees as compared to varus knees (p value <0.001). This study confirmed knee internal rotation in initial stages of flexion, preimplant in arthritic knees during a passive knee flexion assessment. Varus and valgus knee seemed to behave similarly. This mimics the normal knee rotation. Postimplant knees in TKR behave differently

Between the year 1987 to 2005, 45 primary knee replacements were performed for 30 patients affecting ankylosing knee joint. 23 patients were having flexion fused deformities with 38 knee arthroplasty, ten of them were having flexion fused deformities over than 60 degrees. 18 cases were performed ipslateral THR & TKR. 2 AS patients undergone THR, TKR and total ankle replacement on the same anesthesia. The other 7 patients were having extension ankylosing deformities with 9 primary TKR performed. All patients were post infection deformities with the exception of one Rheumatoid Arthritis and one hemophiliac patient with bilateral extension ankylosing deformities of the knee joint. Exposure of the knee joint and separation of the fused bones, providing a mobile joint space plays a crucial procedure for the next step of surgery for both flexion and extension ankylosing deformities. The following 2 points are important:. First separate the fused bone between the femoral condyles and the patella, pay attention to the thickness of the patella button allowing sufficient bone stock with thickness and strength for patella replacement. Separate the fused bone between the femoral and tibial condyles allowing motion and space, pay attention that:. the resection plane is 90 degrees perpendicular to the tibial axis and as proximal to the tibial plateau fused with the femoral condyles as possible. release and protect the blood supply and nerve of the posterior resection area avoiding damage to the nerve endings and the blood vessels. Soft tissue balancing is important, it is difficult to achieve the same flexion and extension gap. Usually the extension gap is narrow than flexion gap with flexion ankylosing deformities, on the contrary the flexion gap is narrow than extension gap with extension ankylosing deformities. Post operative rehabilitation and traction can gradually improve for the patients who less than 20 degrees flexion contracture deformities. For extension ankylosing deformities, post-operative rehabilitation can achieve better results even though the intra-operative ROM is less than 90 degrees but if the patient is stable in extension position

Aims: Prospective randomized single blind investigation was made to evaluate inßuence of two surgical approaches to the knee (antero-medial approach and subvastus approach) for total knee arthroplasty. Materials: Between 1995– 2002 215 consecutive total knee arthroplasties in 204 patients (192 women, 12 men) were made. There are following prosthesis implanted: PFC Ð 74, GSB Ð 45, PFC ∑ Ð 73, Link Ð 5, AGC Ð 18. All patients were evaluated. Patientsñ mean age was 65,7 years old. TKR with antero-medial approach was performed in 98 cases (45 per cent), whereas TKR with subvastus approach was performed in 117 cases (55 per cent). Methods: Functional status according to HSS scale at the 14 days and 6 months after procedure was regard as end results for both protocols. Results: In group with antero-medial approach there were: 26,4% excellent results, 69,8% good results and 3,8% fair results respectively. In group with subvastus approach there were: 24,3% excellent results, 70,2% good results, 3,3% fair and 2,2% poor results respectively. There are no statistical differences between early functional results of these two surgical approaches for total knee replacement. Conclusions: We assumed that subvastus approach is as good as anteromedial one in knee joint exposure but less harmful for extensor apparatus and joint proprioception