Aims

Patient dissatisfaction is not uncommon following primary total knee arthroplasty. One proposed method to alleviate this is by improving knee kinematics. Therefore, we aimed to answer the following research question: are there significant differences in knee kinematics based on the design of the tibial insert (cruciate-retaining (CR), ultra-congruent (UC), or medial congruent (MC))?

Aims

Current guidelines consider analyses of joint aspirates, including leucocyte cell count (LC) and polymorphonuclear percentage (PMN%) as a diagnostic mainstay of periprosthetic joint infection (PJI). It is unclear if these parameters are subject to a certain degree of variability over time. Therefore, the aim of this study was to evaluate the variation of LC and PMN% in patients with aseptic revision total knee arthroplasty (TKA).

Aims

To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty.

Objectives

The monitoring of fracture healing is a complex process. Typically, successive radiographs are performed and an emerging calcification of the fracture area is evaluated. The aim of this study was to investigate whether different bone healing patterns can be distinguished using a telemetric instrumented femoral internal plate fixator.

Purpose of the study: Implants with multidirectional locking screws theoretically have many advantages for the treatment of periprosthetic fractures. In the event of osteoporotic bone, this system of plate fixation ensures stability and better bone fixation. Using screws anchored in the different angles, we proposed rigid fixation around the prosthesis. We conducted a retrospective analysis of outcomes obtained after treatment of perprosthetic femoral fractures, Vancouver B1 and C, comparing two types of implants with angular stability (straight plate and folded plate).

Material and methods: From June 1999 to December 2007, we treated 58 patients with periprothetic fractures of the femur using locking plates. Mean age was 72.4 years, 40 patients were female. Thirty-two patients (55.2%) had a total hip prosthesis, 21 a total knee prosthesis and 5 both types of prosthesis (8.6%). We noted: peri- and postoperative complications, degree of bone healing, degree of mobility (Barthel Mobility index and stand up and go test) as well as the social status of the patients.

Results: Bone healing was obtained in 56 cases (96.5%). In two patients, the implant was dislocated and in four others there were general complications. The mean time necessary to obtain total weight-bearing two-leg stance was 8.6 weeks. Forty-six patients (78%) had the same social status as before the fracture. For mobility, 52 patients (89%) achieved the same level as before fracture. Four other patients required a crutch for walking and two needed a walker. Mean Barthel index was 85 points (max 100) and improved 35 points at onset of rehabilitation. Mean stand up and go was 22 s.

Conclusion: According to the review of the literature, 35% of plates dislocate after osteosynthesis of periprosthetic fractures. In our study, the rate was 3.5%, with 7% general complications. We can thus conclude that the methods presented here enable good bone healing in the majority of cases.

Implants with multidirectional locked screws have theoretical advantages in the treatment of periprosthetic fractures. In osteoporotic bone those locked plate systems with multidirectional applicable screws give a high stability. With the possibility of fixing screws in various angles, a rigid fixation in the presence of a prosthetic implant can be achieved. We concluded a retrospective study of a consecutive series of the outcome of Vancouver B1 and C femoral injuries using two specific locked implants (Straight and wave plate).

From June 1996 to December 2004 we treated 58 patients with a periprosthetic fracture of the femur with a locked plate. The mean age at the index procedure was 72.4 years, 40 patients were female (69%). In 32 cases (55.2%) we saw a hip endoprosthesis, in 21 cases (36.2%) a knee endoprosthesis and in 5 cases both (8.6%). Outcome measures were intra- and postoperative complications, bony union, degree of mobility and social status, Barthel mobility index and “stand up and go” test.

Union occurred in 56 cases (96.5%) after the index procedure. Twice the implant failed, we saw 4 general complications. The mean duration until full weight bearing status in these patients was 8.6 weeks.

At follow up 46 patients (78%) had maintained the same social status as before the fracture. Regarding the mobility status 52 patients (89%) had regained their previous level, 4 patients walking without aid before now required a cane and two patients a walking frame. The mean Barthel Index was 85 points of possible 100 and improved from 35 points at point of beginning of the rehabilitation. The mean stand-up& go time was measured as 22 seconds.

Conclusion: Overall failure rates of osteosynthesis after periprosthetic fractures of up to 35% are reported (20). With 3.5% implant related failures and 7% general complications, the presented Methods: achieve bony union and mobility in a high percentage of cases.

Introduction: Trauma surgeons are often less exposed to large caseloads of primary osteoarthritis, compared to purely “elective”orthopaedic surgeons. The experience in total knee arthroplasty is thereby markedly On the other hand, posttraumatic knee arthrosis is often accompanied by severe deformity and axis deviation. In theory, navigated arthroplasty can overcome some of the problems in this setting.

Aim: Evaluation of the navigated technique of total knee arthroplasty (TKA), including the technical difficulties, the learning curve and the feasibility in severe bony deformity. Setting is a level I trauma center. Study setup was prospective, follow up period on average 14.5 months (11–25 months).

Patients: Between 7/04–6/05 we treated 36 patients with arthritis of the knee related to trauma. 18 patients were male. Average age at TKA was 59 (32–77) years. On average patients had 2.83 previous operations.

Methods: The navigational system used is manufactured by PRAXIM (La Tronche/France). It uses infrared-tracking and bone-morphing software. The implant was a mobile bearing LCS knee (DePuy/USA). Follow up included radiographs, clinical examination and the knee society scores.

Results: In three cases the procedure was finished in a conventional technique, reasons were suspicion of the surgeon about the cuts recommended by the system, a missing femoral cut block and a broken screw of the tracker-fixation. There was no failure of the navigational system. There was a clear learning curve regarding procedure time. Preop mean extension deficit was improved from av. 7.1° (0–30°) to 1.67° (0°–10°) postop., flexion contracture improved from av. 95° to 103°. The combined knee society score (max. 200 pts) improved from 77 pts preop to 156 pts at follow up.

Conclusions: Navigated knee endoprosthesis is reliable tool for the trauma surgeon with few technical problems. Especially for surgeons with less experience in TKA, planning of implant size and position is very helpful. With posttraumatic deformity the surgeon can gain valuable information and assistance to improve alignment and ligamentous balancing.