Restoring global offset and lower limb length with a 3 offset option double-tapered stem

Abstract

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.

Radiographic results on acetabular cup placement with the SuperPath technique: a retrospective study of 756 cases

“…FO was measured as the perpendicular distance from the center of rotation of the femoral head to the long axis of the femoral canal [ 37 ]. AO was measured as the distance from the center of rotation of the femoral head to the perpendicular line passing through the medial edge of the ipsilateral terardrop [ 38 ]. The mean (in degrees) of the values obtained ± standard deviation (SD) was then calculated.…”

The modern state of femoral, acetabular, and global offsets in total hip arthroplasty: a narrative review

“…Research continues to put greater emphasis on global offset, the sum combination of the femoral and acetabular components, as an essential factor when considering its subsets in the realm of offset. Biggi et al ( 34 ) underline that, since the global offset takes into account both acetabular and femoral offset, it is a more reliable joint parameter when restoring hip parameters after primary THA than femoral offset alone ( Table 3 ). Because femoral and acetabular offsets may be individually changed, however, this raises a question about whether the overall global offset should be resultingly decreased, increased, or maintained.…”

“…Global offset seemed not as important as femoral offset Biggi et al . ( 34 ) 2020 80 patients Retrospective 4.4 years (range: 3.2–5.7) Preoperative ipsilateral offset NA ΔGO within ±5 mm range. The use of a 3-offset femoral stem was effective in restoring native global offset Weber et al .…”

Clinical Outcomes for Total Hip Arthroplasty with and without Previous Curved Periacetabular Osteotomy

“…However, there are no reports on global offset (GO), measured as the sum of AO and femoral offset (FO) [ 24 ], after THA with previous PAO. GO after THA is important to obtain good HHS, and therefore, it should also be investigated [ 25 ].…”