Long-term outcomes of cementless femoral stem revision with the Wagner cone prosthesis

Background The procedure of femoral stem revision is challenging, and bone conservation with less stress shielding is a mandatory effort in these cases. Although there are several reports of stem revision with stems designed for primary total hip arthroplasty (THA), there is no report on stem revision with the Wagner cone prosthesis. Methods Between 1996 and 2008, 41 hips of 41 consecutive patients were subjected to femoral revision THA using the Wagner cone prosthesis. The mean age during revision surgery was 56.1 years, and the mean follow-up period was 14.8 years. The clinical results were evaluated, and the femoral component was assessed radiologically. Results The results showed that the average period from the first operation to revision THA was 8.0 years. Additionally, the mean Harris hip score improved from 52 points preoperatively to 83 points at the final follow-up. All stems showed bone integration in the radiological evaluation. A subsidence of more than 5 mm was observed in 3 out of 28 (10.7%) femoral stems. Two patients needed an acetabular revision for acetabular cup loosening during the follow-up period. Furthermore, one patient had recurrent dislocation and had to undergo revision surgery for soft tissue augmentation. Conclusions We achieved favorable clinical and radiological long-term outcomes in femoral stem revision using the Wagner cone prosthesis. This cementless femoral stem could be an option for femoral stem revision in cases with relatively good bone stock.

Comparison of Forces Applied During Inserting A Cementless Femoral Stem Versus A Test To Failure: A Pilot Trial

Background The increasing number of total hip arthroplasties (THA) and the more common use of uncemented stems are leading to an increasing incidence of intraoperative proximal femoral fractures (IPFF), making them a clinically relevant complication. When inserting the stem, the surgeon has to find a compromise between sufficient anchorage and the risk of fracture. Only a few biomechanical studies investigated forces that are necessary, or already risky, when inserting a femoral stem. Therefore, the aim of the study was to determine the forces occurring during the insertion of the stem and the forces that lead to IPFF. Methods Two female chemically untreated fresh-frozen human cadavers, aged 71 and 83 years and weighed 54 kg and 65 kg respectively, underwent left and right implantation of a THA stem by an experienced orthopaedic surgeon. The insertion of the stem was followed by a failure test, in which the surgeon hit the stem so hard that a fracture occurred. The forces, occurred while insertion and test to failure, were measured using an impulse hammer. Results The observed forces varied greatly. Over the four performed implantations, the forces ranged from 1317.7 N to 4347.5 N during insertion, and from 526.5 N to 7383.9 N during the failure test. The comparison between insertion versus failure test showed significantly higher peak forces (P < 0.001, P < 0.001, P = 0.002) in the failure test for implantations 1, 3 and 4. The comparison was not possible for implantation 2 because of a sensor error. Conclusions The biomechanical experiments presented in this study have shown that even with the small number of implantations, significantly higher hammering forces were required to cause a visually or acoustically perceptible IPFF than were necessary for adequate seating of the femoral stem. However, as fractures often cannot be perceived intraoperatively, it is important to advance the development of supporting systems for intraoperative use.

Correction to: Short‑term results of a new self‑locking cementless femoral stem: a prospective cohort study of the Lima MasterSL

The article Short‑term results of a new self‑locking cementless femoral stem: a prospective cohort study of the Lima MasterSL, written by C. E. Dlaska, I. A. Jovanovic, A. L. Grant, G. Graw, M. P. Wilkinson, K. Doma, K. Hazratwala, was originally published electronically on the publisher’s internet portal on 02 March 2020 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed on 12 December 2020.

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

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.