Objective :To retrospectively review the results at minimum ten years after surgery of a consecutive series of total knee arthroplasties (TKAs) performed using a constrained condylar implant in patients with severe coronal plane instability.Materials and Methods :The series comprised of 44 patients (45 knees) who received primary (19 knees) or revision (26 knees) TKA with a constrained condylar implant between 2001 and 2003 at a single institution.Results :There were no revisions or any other surgery related complications at a mean implantation time of 11.0 years. In 38 patients (15 knees in the primary group and 24 knees in the revision group) who were available for clinico-radiographic follow-up at a minimum of ten years, there was no sign of radiographic loosening. Two patients showed cortical hypertrophy at the extension stem tip but none complained of pain around the stem tip.According to the TLKSS score grading, 73% of the patients in the primary group had results categorized as good or excellent, while 54% of the patients in the revision group had fair results. Four patients (one (7%) in the primary group and three (13%) in the revision group) had poor results. The median WOMAC Index was 80.2% (interquartile range: 74.0% - 81.2%) and 74.0% (interquartile range: 72.1% - 75.8%) in the primary and in the revision groups, respectively (p=0.010).Conclusion :This study showed satisfactory clinical outcomes with no re-operations at minimum ten years after implantation in patients who had undergone primary or revision TKA with a condylar constrained implant.
Background
A proper restoration of hip biomechanics is fundamental to achieve satisfactory outcomes after total hip arthroplasty (THA). A global hip offset (GO) postoperatively reduction of more than 5 mm was known to impair hip functionality after THA. This study aimed to verify the restoration of the GO radiographic parameter after primary THA by the use of a cementless femoral stem available in three different offset options without length changing.
Methods
From a consecutive series of 201 patients (201 hips) underwent primary cementless THA in our center with a minimum 3-year follow up, 80 patients (80 hips) were available for complete radiographic evaluation for GO and limb length (LL) and clinical evaluation with Harris hip score (HHS). All patients received the same femoral stem with three different offset options (option A with – 5 mm offset, option B and option C with + 5 mm offset, constant for each sizes) without changing stem length.
Results
Mean GO significantly increased by + 3 mm (P < 0.05) and mean LL significantly decreased by + 5 mm (P < 0.05) after surgery, meaning that postoperatively the limb length of the operated side increased by + 5 mm. HHS significantly improved from 56.3 points preoperatively to 95.8 postoperatively (P < 0.001). Offset option A was used in 1 hip (1%), B in 59 hips (74%) and C in 20 hips (25%).
Conclusions
The femur is lateralized with a mean of + 5 mm after surgery than, the native anatomy, whatever type of stem was used. Thus, the use of this 3-offset options femoral stem is effective in restoring the native biomechanical hip parameters as GO, even if 2 offset options were considered sufficient to restore GO.
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