Preservation of the PCL when performing cruciate-retaining TKA: Is the tibial tuberosity a reliable predictor of the PCL footprint location?

PURPOSE: Reconstruction of the joint line is crucial in total knee arthroplasty (TKA). A routine height of tibial cut to maintain the natural joint line may compromise the preservation of the PCL. Since the PCL footprint is not accessible prior to tibial osteotomy, it seems beneficial to identify a reliable extraarticular anatomic landmark for predicting the PCL footprint and being visible within standard TKA approach. The fibula head predicts reliably the location of PCL footprint; however, it is not accessible during TKA. The aim of this study now was to analyze whether the tibial tuberosity can serve as a reliable referencing landmark to estimate the PCL footprint height prior to tibial cut. METHODS: The first consecutive case series included 216 CR TKA. Standing postoperative lateral view radiographs were utilized to measure the vertical distance between tibial tuberosity and tibial osteotomy plane. In the second case series, 223 knee MRIs were consecutively analyzed to measure the vertical distance between tibial tuberosity and PCL footprint. The probability of partial or total PCL removal was calculated for different vertical distances between tibial tuberosity and tibial cutting surface. RESULTS: The vertical distance between the tibial tuberosity and tibial cut averaged 24.7 ± 4 mm. The average vertical distance from tibial tuberosity to proximal and to distal PCL footprint was found to be 22 ± 4.4 and 16 ± 4.4 mm, respectively. Five knees were considered at 50% risk of an entire PCL removal after CR TKA. CONCLUSIONS: Current surgical techniques of tibial preparation may result in partial or total PCL damage. Tibial tuberosity is a useful anatomical landmark to locate the PCL footprint and to predict the probability of its detachment pre-, intra-, and postoperatively. This knowledge might be useful to predict and avoid instability, consecutive pain, and dissatisfaction after TKA related to PCL insufficiency. LEVEL OF EVIDENCE: III.

Comparative study of elbow disorders in young high-performance gymnasts.

The study aimed to investigate the prognosis of osteochondral affection (e.g., osteochondritis dissecans (OCD), cartilage lesions, fractures and bone edema in the elbows of high-performance gymnasts (n=30) compared to prognosis results with athletes not undergoing excessive stress on the upper extremity (n=29). The study also tested a novel isotropic 3D-FSE-sequence (CUBE) technique as an early diagnostic modality. Standard protocol was used to conduct the MRI examinations, which were then compared to results from the CUBE - sequence. The gymnast group (p=0.012) presented a significantly higher prevalence of complaints in the elbow joint compared to the other athlete group. Furthermore, osteochondral lesions in MRIs appeared more frequently in the group of gymnasts (n=10, 33%, p=0.033), including 7 cases (23%) of OCD. In the control athlete group 2 asymptomatic cases of OCD and one case of bone edema were detected. The MRI investigation with the CUBE - sequence showed similar results as the standard MRI protocol in terms of the diagnosis sensitivity. The current study indicates that juvenile gymnasts are at a higher risk for osteochondral lesions of the elbow than athletes without excessive stress on the upper extremities.