Comparable accuracy of femoral joint line reconstruction in different kinematic and functional alignment techniques.

PURPOSE: A key part of kinematic alignment (KA) and functional alignment (FA) is to restore the natural femoral joint line, in particular the medial joint line. KA is known to reproduce the femoral joint line accurately; however, direct comparisons with other surgical techniques such as FA are currently lacking. The purpose of this study was to evaluate differences of alignment parameters in KA and FA techniques with a special focus given to the femoral joint line. METHODS: We performed a retrospective radiological analysis of pre- and postoperative long leg radiographs of 221 consecutive patients with varus or neutral leg alignment, who underwent primary total knee arthroplasty (TKA) procedures from 2018 to 2020. Patients were assigned to one of four groups: (1) FA: image-based robotic-assisted TKA, (2) FA: imageless robotic-assisted TKA, (3): restricted KA: 3D cutting block-assisted (patient-specific instruments, PSI) TKA, (4): unrestricted KA: calipered technique. Patients' radiographs were (re)-analyzed for overall limb alignment, medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), as well as medial and lateral femoral joint line alteration. Statistical significance was determined using unpaired t testing (FA vs. KA group) and one-way ANOVA (subgroup analyses). RESULTS: Comparisons of KA vs. FA, as well as individual subgroups of KA and FA did not show any differences in the accuracy of medial joint line reconstruction (< 2 mm, p = 0.384, p = 0.744, respectively) and LDFA alteration (< 2°, p = 0.997, 0.921, respectively). Correction of MPTA (3.4° vs. 2.2°) and lateral femoral joint line (2.1 mm vs. 1.5 mm) was higher for FA and FA subgroups compared to KA and KA subgroups (both p < 0.001). CONCLUSION: Kinematic and functional alignments showed a comparable accuracy in reconstruction of the medial femoral joint line and femoral joint line orientation. Increased correction of MPTA and lateral femoral joint line was recorded with FA techniques. LEVEL OF EVIDENCE: III.

What you need to know about kinematic alignment for total knee arthroplasty.

This lecture outlines the various alignment philosophies for total knee arthroplasty (TKA). It is logical that our desire to improve clinical outcomes for TKA involves a more personalized and physiological implantation process that preserves each patient's anatomical features. We will take a deep dive into the kinematic alignment concept by describing its rationale, surgical steps and results. Kinematic implantation of TKA can be done reliably at a low cost and appears to achieve acceptable implant biomechanics. While its short-term clinical results are encouraging, it must be evaluated further. The thresholds for acceptable alignment (indications for restricted kinematic alignment) still need to be specified. LEVEL OF EVIDENCE: V; Expert opinion.

Short-term follow-up of kinematically vs. mechanically aligned total knee arthroplasty with medial pivot components: A case-control study.

INTRODUCTION: The kinematic alignment (KA) technique for total knee arthroplasty (TKA) and the medial pivot (MP) component design are two options promoting a physiologic prosthetic knee kinematics when used in combination that could improve TKA outcomes. Case-control study is initiated to compare the 1-year radio-clinical outcomes between kinematic alignment medial pivot total knee arthroplasty (KA MP-TKAs) and mechanical alignment medial pivot total knee arthroplasty (MA MP-TKA). Goal of a study was to answer the following questions: Do KA MP-TKAs patients have improved functional outcomes compared to MA MP-TKAs patients? (Q1); Do prosthetic knee and lower limb alignments differ between KA and MA patients (Q2)? And does kinematic implantation of MP TKA has higher risk of reoperations and revisions (Q3)? MATERIAL AND METHODS: A case-control study was carried out to compare the 1-year clinical and radiographic outcomes between 24 consecutive KA-TKA patients and 24 matched MA-TKA patients. All patients had implantation with manual instruments and a cemented medial pivot TKA with excision of the PCL. All data were collected prospectively, and outcome scores were patient reported. RESULTS: KA patients had superior values in Forgotten Joint Score (FJS) at 1-year (KA 77 vs. MA 51) (p=0.05) follow-up. After one year KA patients scored better in objective section of the new Knee Society Score (KSS) (p=0.02), and in sport section of the Knee Osteoarthritis Outcome Score (KOOS) (p=0.01). Eleven out of 24 patients (46%) in KA group and 7/24 patients (29%) in MA group had limb alignment out of 180°±3°, whereas 17/24 (70%) of KA patients, and 14/24 (58%) of MA patients had orientation of tibial component with more than 3° of varus. No reoperation or revision occurred in either group. DISCUSSION/CONCLUSION: The KA of MP TKA design seems to have a good efficacy at early-term, with some 1-year functional performance higher to the ones from MA MP TKAs. Further research is needed to define if those early results will last over time. LEVEL OF EVIDENCE: III, case-controlled study.

[The significance of the ovarian arteriolar vasodilatation in pathogenesis of the ovarian hyperstimulation syndrome].

Ovarian hyperstimulation syndrome is a complication of the ovulation stimulation, most commonly by gonadotrophins. It frequently occurs in patients included in in vitro fertilization program. The exact mechanism of development of this syndrome has not been elucidated yet. The basic pathogenic mechanism of development of this syndrome is vasodilation of the ovarian blood vessels. Dilated ovarian blood vessels become permeable. Permeability of dilated ovarian blood vessels is more increased by released ovarian mediators. Due to increased permeability of the blood vessels, there is leakage of the intravascular fluid into the extravascular areas resulting in hypovolemia, edema and ascites. Hypovolemia leads to renal perfusion decrease. Increased salt and water reabsorption occurs in the renal tubules so oliguria develops. Decreased arterial blood volume results in stimulation of the renin-angiotensin-aldosterone system, the sympathetic nervous system as well as the antidiuretic hormone. The activation of the sympathetic nervous system via beta adrenergic receptors stimulates renin release and aldosterone secretion. Renin stimulates release of angiotensin I which transforms into angiotensin II. Angiotensin II increases the pressure and stimulates aldosterone secretion. In patients with this syndrome, there is an elevated plasma endothelin and natriuretic peptide level. Endothelin is an important vasoconstrictor. It increases secretion of renin, aldosterone, catecholamines, antidiuretic hormone, and atrial natriuretic peptide, and enhances the vasoconstrictive effect of norepinephrine and angiotensin II. The platelet number increase together with the elevated factor of blood coagulation and hyperviscosity in a severe form of this syndrome may result in development of intravascular thrombosis. The treatment consists of maintenance of circulatory function, i.e. the increase of effective arterial blood volume by applying the plasma volume expanders.

[Early results of cementless hip arthroplasty in the treatment of femoral head posttraumatic and atraumatic osteonecrosis].

AIM: To evaluate the value of cementless hip arthroplasty in the treatment of posttraumatic and atraumatic osteonecrosis (ON) of the femoral head. METHODS: The study was conducted at the Department of Orthopedics and Traumatology, Military Medical Academy, between January 1st, 1999 and December 31st, 2003. Twenty-five patients with 27 implanted endoprostheses, and the diagnosis of osteonecrosis of the femoral head, and radiographically confirmed Arlet-Ficat stage III and IV were evaluated retrospectively. The results were evaluated according to Harris Hip Score (HHS). The research included 10 patients with traumatically induced osteonecrosis and 15 patients (17 endoprothesis) with osteonecrosis of the femoral head. The mean age of the patients in the group with posttraumatic osteonecrosis of the femoral head was 41 (19-62) years, and in the group of the patients with atraumatic osteonecrosis of the femoral head it was 40.2 (21-53) years. Complications included one case with postoperative luxation, and one case with iatrogenic sciatic nerve palsy. RESULTS: The average Harris Hip Scores in the group of posttraumatic osteonecrosis were 31 points preoperatively and 86 points postoperatively. In the group of osteonecrosis of atraumatic etiology, the average Harris Hip Score was 28 points preoperatively, and 77 points postoperatively. Postoperative Harris Hip Scores were compared with the Student's t-test and the results showed no statistically significant difference (p = 0,125). CONCLUSIONS: Our study did not find any significant difference between the results of posttraumatic and atraumatic osteonecrosis of the femoral head treated with cementless endoprosthesis.