Mechanical Alignment in Knee Replacement Homogenizes Postoperative Coronal Hip-Knee-Ankle Angle in Varus Knees: A Navigation-Based Study.

After knee replacement, postoperative lower limb alignment is influenced by the geometry of the prosthesis position and surrounding soft tissue that contributes to the hip-knee-ankle (HKA) angle. The purpose of this study is to determine the dynamic coronal HKA angle after mechanical alignment in total knee replacement using computer navigation. We conducted a pre-post design study of 71 patients with varus osteoarthritic knees on which total knee arthroplasty was performed. The HKA was measured before and at the end of the surgical procedure with the patient in the supine position using a navigation system at 30, 60, and 90 degrees of knee flexion. Postoperative implant position and flexion and extension gaps were assessed. HKA was clustered in three preoperative dynamic patterns (PDPs; Varus-Neutral, Varus-Valgus, and Varus-Varus). There were statistically significant differences in the dynamic coronal HKA between the preoperative and postoperative statuses after mechanically aligned knee replacement (with p < 0.0001) Before the surgical procedure, statistically significant differences were found between patterns at any angle of flexion confirming a well-differentiated preoperative dynamic behavior between the three groups. Postoperatively, 98.6% (71 out of 72) of the knees were within ± 3 degrees of the HKA at full extension. Fifty-eight knees (80.6%) were assessed to a "within-range" postoperative dynamic alignment at any grade of flexion considered. There are differences between the preoperative and postoperative status of the dynamic coronal HKA angle after mechanically aligned knee replacement. We proposed that an excellent dynamic HKA alignment is achieved not only at full extension within the range of 0 ± 3 degrees but also when this alignment is maintained at 30, 60, and 90 degrees.

Dynamic Alignment Analysis in the Osteoarthritic Knee Using Computer Navigation.

The lower limb alignment is influenced by the geometry of the joint surfaces and surrounding soft tissue tension. The mechanical behavior changes in a normal, osteoarthritic, and postoperative knee. The purpose of this study is to determine the dynamic coronal femoral tibial mechanical angle (FTMA) in osteoarthritic knees using computer navigation. The authors hypothesize that there are different varus-valgus patterns between flexion and extension in the osteoarthritic knee. We conducted a transversal observational study and included patients with osteoarthritis who underwent primary navigation TKA (Orthopilot version 4.2; B. Braun Aesculap, Tuttlingen, Germany). In total, 98 consecutive patients with 100 osteoarthritic knee joints, on which total knee arthroplasty was performed in our institution from 2009 to 2010, were enrolled in this prospective study. The FTMA was measured with the patient supine with maximum knee extension possible (considering the value as 0), 30, 60, and 90 degrees. All FMTA data obtained were segmented by hierarchic cluster measuring method. Through the clustering system, five segments were generated for varus patients and three for valgus patients: expected varus, expected valgus, severe varus, severe valgus, structured varus, structured valgus, concave varus, mixed varus-valgus, and mixed valgus-varus. The findings of the present study have demonstrated that there is a well-defined dynamic alignment in osteoarthritic knees, resulting in a wide kinematic variation in the coronal FTMA between flexion and full extension. Further studies will be necessary to determine whether this dynamic approach to FTMA has clinical utility in the surgeon's decision-making process.

The role of Weil and triple Weil osteotomies in the treatment of propulsive metatarsalgia.

BACKGROUND: The Weil and triple Weil osteotomy are widely used to treat third rocker metatarsalgia. The aim of this study was to analyze the results and complications of Weil and triple Weil osteotomy used for the treatment of third rocker metatarsalgia. METHODS: This is a report of 82 patients who were operated due to third rocker metatarsalgia from March 2004 to May 2007. A total of 76 completed the study, 68 women and eight men, with a total of 93 operated feet, 52 right and 41 left ( 17 bilateral). The clinical results were evaluated using the AOFAS score for the assessment of lesser metatarsals and interphalangeal joints, and weightbearing lateral and AP foot X-ray for radiological evaluation. RESULTS: The median AOFAS score was 90 (range, 34 to 100). We had good results in 80% and unsatisfactory in 20%. Prior to surgery 75 feet were index minus, but after all 81 feet were plus-minus. With regard to complications, we had serious recurrence of metatarsalgia in 4.3%, moderate stiffness in 60.2% (severe in one case), floating toes in 4.3% and delays in bone healing in 7.5%. CONCLUSION: We believe that Weil and triple Weil osteotomies are effective procedures in the treatment of third rocker metatarsalgia. We feel preoperative planning with tracing on the weightbearing AP radiographs is an essential step.