Prospective validation of an indication algorithm for UKA

Aims and Objectives: Patients with isolated medial gonarthrosis benefit from a treatment with a unicompartmental knee arthroplasty (UKA) compared to a total knee arthroplasty (TKA). They have a shorter rehabilitation time, better function, lower morbidity and a higher satisfaction rate. However, the revision rate is higher than in patients with TKA. Patient selection and the resulting incorrect indication may be one reason. Hamilton et al.’s research group prepared a radiological “decision aid” for the indication of a UKA. The aim of this study was to validate this uncomplicated diagnostic procedure based on intraoperative findings. Materials and Methods: In this prospective study, 85 patients received routinely conventional x-rays. Strictly lateral and anterior-posterior view as well as varus/valgus stress x-rays were taken. Using Hamilton et al.’s “desiscion aid”, the x-ray images were preoperatively evaluated with regard to medial and lateral cartilage damage and the function of the anterior cruciate ligament. The cartilage damage of the individual tibial and femoral compartments was also scaled and documented intraoperatively. The results of the decision aid were validated with regard to the intraoperative findings. Indication-justifying cartilage damage was defined as focal complete cartilage loss. The sensitivity (SEN) and specificity (SPE) of decision aid with regard to cartilage damage in the medial and lateral compartments and the functionality of the anterior cruciate ligament were determined. Results: In the area of the medial compartment, decision aid has a SEN and PES of 79.4% and 82.4% respectively. The SEN and SPE for lateral compartments are 98.5% and 55.0%, respectively. Intact ACLs are correctly diagnosed at 94.7%. Insufficient ACLs at 33.3%. Conclusion: These data suggest that according to our findings, only about 2 out of 10 patients are not reliably diagnosed with medial gonarthrosis. However, about 2 out of 10 patients are diagnosed with medial gonarthrosis, which does not yet have to be treated with UKA. Furthermore, it could be shown that almost all patients with a completely laterally preserved cartilage are also recognized as such. However, every second patient with relevant cartilage damage is not radiologically identified. These data refer only to the radiological findings. Coupled with the patient’s medical history and clinic, the “Desicion Aid” is a very good aid for the correct indication for a UKA.

Reliability of Roentgenographic Knee Alignment Measurements in Gonarthrosis

A reliable method of measuring knee alignment is critical in the preoperative planning of high tibial osteotomy (HTO). This radiological study, based on the measurements of the mechanical and anatomical axes of the lower limb, aimed to determine which method would be more reliable and reproducible. From 2004 to 2013, 50 consecutive patients (50 knees) with medial gonarthrosis were treated with valgus-producing HTO. Four independent investigators assessed preoperative standing lower limb radiography (including hip, knee, and ankle joints) to measure both anatomical and mechanical axes. We defined a response as a difference in the angle measured by the same investigator using the same method. The covariates were the investigators and methods. To account for both inter- and intraobserver variabilities, all data were evaluated using a generalized estimating equation model. The results revealed that the effect of the investigators was not statistically significant; however, the effect of the measurement method was highly significant (p < 0.0001). The estimated coefficient of the anatomical axis method was negative, indicating that the reproducibility of the anatomical axis method was better than that of the mechanical axis.

Proximal Tibia Medial Biplanar Retrotubercle Open Wedge Osteotomy for Varus Knees with Medial Gonarthrosis

Objectives: The purpose of this study is to evaluate the early results of proximal tibia medial biplanar retrotubercle open wedge osteotomy for varus gonarthrosis and compare the results with the literatüre. Methods: The results of proximal tibia medial biplanar retrotubercle open wedge osteotomy for 23 knees of 22 patients with medial gonarthrosis were evaluated clinically and radiologically. Results: Twenty of the patients were female and two were male. Mean age of the patients was 56.24; mean boy mass index was 31.95 and preoperative HSS (Hospital for Special Surgery) score was 68.7. Mean tibiofemoral axis was 186.39° and mean Insall-Salvatti index value was 1.04 preoperatively. Mean follow up period was 30.19 months. Mean HSS score was 86.48, femorotibial anatomic axis angle was 175° and Insall-Salvati index value 1.06 during the last follow-up. The improvement of the HSS score and the femorotibial anatomic axis angle was statistically significant. However, the change in Insall Salvati index values was statistically insignificant. Nonfatal pulmonary embolus in 1 patient, and deep vein thrombosis that occured one year after the procedure in 1 patient, rhabdomyolysis in 1 patient and loss of correction (relapse) in 1 patient were encountered as complications. Conclusion: Our results show that proximal tibia medial biplanar retrotubercle open wedge osteotomy improves the frontal and sagittal plane deformities without changing the patellar tendon length. Hence, possible patellofemoral problems are prevented and the clinical results are improved.