With greater numbers of younger patients undergoing total hip replacement (THR), the effect of patient age on the diameter of the femoral canal may become more relevant. This study aimed to investigate the relationship between the diameter of the diaphysis of the femoral canal with increasing age in a large number of patients who underwent THR. A total of 1685 patients scheduled for THR had their femoral dimensions recorded from calibrated radiographs. There were 736 males and 949 females with mean ages of 67.1 years (34 to 92) and 70.2 years (29 to 92), respectively. The mean diameter of the femoral canal was 13.3 mm (8.0 to 23.0) for males and 12.7 mm (6.0 to 26.0) for females. There was a poor correlation between age and the diameter of the canal in males (r = 0.071, p = 0.05) but a stronger correlation in females (r = 0.31, p < 0.001). The diameter of the femoral canal diameter of a female patient undergoing THR could be predicted to increase by 3.2 mm between the ages of 40 and 80 years, in contrast a male would be expected to experience only a 0.6 mm increase during the same period. This increase in the diameter of the canal with age might affect the long-term survival of the femoral component in female patients. Cite this article: Bone Joint J 2013;95-B:339–42

We have investigated the use of a conically-shaped cement plug made of Polyactive (PA), a biodegradable copolymer. The flexibility and hydrogel properties were thought to facilitate occlusion of the femoral canal even when it was oval or irregular in shape. The function of the plug was first compared with that of the Thackray polyethylene model in 16 artificial plastic femora. The maximum intramedullary pressure achieved during cementing was ten times higher with the biodegradable model. Migration or leakage of cement did not occur when the diameter of the femoral canal was equal to or smaller than the diameter of the plug. We also showed that the biodegradable properties of this implant were such that it did not require removal during revision. The new plug was tested in a pilot clinical trial. At two years only two out of 21 patients had evidence of migration or leakage of cement, probably due to a mismatch in the size of plug and femoral canal. There were no local changes in the femur

Objectives. In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. Patients and Methods. We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject–specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year. Results. Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively. Conclusions. The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding. Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362–369. DOI: 10.1302/2046-3758.59.2000525

Traditional mechanical debridement can only remove visibly infected tissue and is unable to completely clear all the biofilm that hides within muscle crevices and nerves. This study aims to determine the results of single-stage revision using noncontact low frequency ultrasonic debridement in treating chronic periprosthetic joint infections (PJI). A prospective study of consecutive patients requiring single-stage revision for chronic PJI was performed since August 2021. After mechanical debridement, an 8‑mm handheld non‑contact low‑frequency ultrasound probe was used for ultrasonic debridement at a frequency of (25±5) kHz and power of 90% for 5 minutes. Each ultrasound lasted 10 seconds with 3‑seconds intervals. The probe was repeatedly sonicated among all soft tissue and bsingle interface. The distal femoral canal and the posterior capsule of the knee were fully sonicated with a special right‑angle probe. Chemical debridement was then performed to irrigation the whole operative area. Recurrence of infection, culture results and number of colonies 24 hours after ultrasonic debridement were recorded. A total of 45 patients (25 hips and 20 knees) were included and 43 of them (95.6%) were free of infection at a mean follow-up time of 29 months (24 to 33). There were no intraoperative complications related to ultrasonic debridement (neurovascular and muscle injury, poor wound healing and fat liquefaction). The culture‑positive rate of wound liquid before ultrasonic debridement was 40.0% (18/45), which significantly increased to 75.6% (34/45) after ultrasonic debridement (P=0.001). The median number of colonies 24 hours after ultrasonic debridement was 2372 CFU/ml (310 to 4340 CFU/ml), which was significantly higher than that before debridement (307 CFU/ml; 10 to 980 CFU/ml) (P=0.000). Single-stage revision with non‑contact low‑frequency ultrasonic debridement can fully expose bacteria within biofilm, increase the efficacy of chemical debridement and lead to a favorable short‑term outcome without related complications

Although data on uncemented short stems are available, studies on cemented short-stemmed THAs are limited. These cemented short stems may have inferior long-term outcomes and higher femoral component fracture rates. Hence, we examined the long-term follow-up of cemented short Exeter stems used in primary THA. Within the Exeter stem range, 7 stems have a stem length of 125 mm or less. These stems are often used in small patients, in young patients with a narrow femoral canal or patients with anatomical abnormalities. Based on our local database, we included 394 consecutive cemented stems used in primary THA (n=333 patients) with a stem length ≤125 mm implanted in our tertiary referral center between 1993 and December 2021. We used the Dutch Arthroplasty Registry (LROI) to complete and cross-check the data. Kaplan-Meier survival analyses were performed to determine 20-year survival rates with stem revision for any reason, for septic loosening, for aseptic loosening and for femoral component fracture as endpoints. The proportion of male patients was 21% (n=83). Median age at surgery was 42 years (interquartile range: 30–55). The main indication for primary THA was childhood hip diseases (51%). The 20-year stem survival rate of the short stem was 85.4% (95% CI: 73.9–92.0) for revision for any reason and 96.2% (95%CI: 90.5–98.5) for revision for septic loosening. No stems were revised for aseptic femoral loosening. However, there were 4 stem fractures at 6.6, 11.6, 16.5 and 18.2 years of follow-up. The stem survival with femoral component fracture as endpoint was 92.7% (CI: 78.5–97.6) at 20 years. Cemented short Exeter stems in primary THA show acceptable survival rates at long-term follow-up. Although femoral component fracture is a rare complication of a cemented short Exeter stem, orthopaedic surgeons should be aware of its incidence and possible risk factors

Aims. In patients where the proximal femur shows gross deformity due to degenerative changes or fracture, the contralateral femur is often used to perform preoperative templating for hip arthroplasty. However, femurs may not be symmetrical: the aim of this study was to determine the degree of variation between hips in healthy individuals and to determine whether it is affected by demographic parameters. Materials and Methods. CT-scan based modelling was used to examine the pelvis and bilateral femurs of 345 patients (211 males, 134 women; mean age 62 years (standard deviation (. sd). 17), mean body mass index 27 kg/m. 2. (. sd. 5)) representing a range of ethnicities. The femoral neck-shaft angle (NSA), femoral offset (FO), femoral neck version (FNV), femoral length (FL), femoral canal flare index (fCFI), and femoral head radius (FHr) were then determined for each patient. All measurements were constructed using algorithm-calculated landmarks, resulting in reproducible and consistent constructs for each specimen. We then analyzed femoral symmetry based on absolute differences (AD) and percentage asymmetry (%AS) following a previously validated method. Results. We found an asymmetry > 2% for NSA (mean AD 2.9°, mean %AS 2.3; p = 0.03), FO (AD 3.8 mm, %AS 9.1 ; p = 0.01), FNV (AD 5.1°, %AS 46.7 ; p = 0.001) and fCFI (AD 0.2 mm, %AS 5.4 ; p = 0.7). Significant relationships were found for AD regarding NSA and ethnicity (p = 0.037), FL and height (R. 2.  = 0.22), and fCFI and gender (R. 2.  = 0.34). Conclusion. Our data confirm the presence of asymmetry of proximal femurs, which is mostly independent of demographic parameters. In cases where contralateral templating is used, such asymmetry may lead to inaccurate anatomical restoration of the hip if the templated sizes are routinely implanted. However, the clinical impact cannot be determined from our investigation. Cite this article: Bone Joint J 2018;100-B:839–44

We report on a cadaveric study and early experience using patient specific drill guides to prevent cortex perforations and reduce the need for a trochanteric osteotomy in revision THA. Mimic software (Materialise) was used for 3D analysis of the cement mantle and cement plug. Based on the CT findings a Cannulated drill guide with the shape of the femoral stem was printed in medical graded nylon intraoperative findings and complications were recorded on videotape using a standard 5mm laparoscope for medullary inspection. Surgical Technique was to attain a pre-operative CT scan with MARS protocol of the proximal femur to evaluate the femoral stem positioning, the 3D anatomy of the cement mantle, the length of the cement plug and the quality of the surrounding bone. Subsequent a 3D printing of patient specific cannulated drill guide with the shape of the removed femoral component but an eccentric cannulation was made. Endoscopic inspection was performed of the inside of the cement mantle, then insertion of the autoclaved cannulated drill guide in the existing cement mantle. After perforation of the distal plug through the PSI drill guide using either a long drill or an ultrasound plug perforation tool (Zimmer Biomet, Warsaw) the excessive cement was removed with standard available flexible femoral shaft reamers (Zimmer Biomet). Further laproscopic examination of the femoral canal performed to verify completeness of the cement removal. Results. CT scans with 3D reconstruction of the existing cement mantle is possible using Modern CT with MARS protocols. After the training on sawbones and cadaveric bones a predictable plug perforation was obtained in all clinical cases. There were no intraoperative cortex perforations and no intraoperative femoral fractures. Conclusion. CT scan analysis of femoral cement mantles together with patient specific drill guides are promising tools to reduce the risk of femoral perforation in revision total hip arthroplasty

Occlusion of the femoral canal is an important step in cemented hip arthroplasty. The goal of occlusion is to allow cement pressurisation and prevent cement egress into the femoral diaphysis. There are numerous designs of cement plugs made out of different materials but there is no consensus or clinical guideline for the choice of cement restrictors. At our centre two types of plugs are used – autologous bone block from femoral canal and the gelatine C-plug (Depuy International). We conducted this study to evaluate the stability of these two plugs and their effect on quality of cementation. The purpose of our study was to assess retrospectively both the length of the “cement tail” i.e. the length of the cement column distal to the stem tip and the cement mantle quality in both groups. A retrospective comparative review was designed after approval from the local R & D department. Power analysis indicated that a minimum of 74 patients per group would be needed. A total of 203 consecutive patients were analysed, 89 received an autologous bone block and 114 had C-plugs. Apart from the plugs both the groups were treated similarly with regards to surgical approach, cementing and operative technique. Surgical technique was to achieve adequate pressurisation and a minimum length of cement tail. Immediate post-operative radiographs were used for analysis. The primary outcome measure was the length of the cement tail, i.e. the length of the cement column from the tip of the stem. The secondary outcome measure was the quality of cementing which was quantified using Barrack's grading. The data was tested for normality using the Shapiro-Wilk test. The means of cement tail lengths in between the two groups were compared using the Wilcoxon ranked sum test. The cementation grades were compared using ANOVA. The correlation between the length of cement tail and the quality of cementation was calculated using ordinal regression. Both the groups were similar in terms of age, sex and primary diagnosis. The mean cement tail length was 6.42 (SE 0.71 mms; range-0–31) in the bone block group and 17.11 (SE-1.34 mms; range 0–65.7 mms) in the C-plug group. This difference was statistically significant (p< 0.0001). The proportion of patients with good quality of cementation (grade A) was significantly higher in the bone block group (80.6%) as compared to the C-plug group (56%) (p < 0.0001). There was a negative correlation between the length of the cement tail and the Barrack grade (rho=0.398), indicating that a short cement tail is associated with better quality cementation. Quality of cementation is of paramount importance in cemented hip arthroplasty. Revision surgery can be more difficult and higher risk in the presence of a long cement tail. We have shown that better quality cementation and shorter cement tails can be achieved with the cheapest of all options for canal occlusion, an autologous bone block and recommend its use

Femoral revision after cemented total hip replacement (THR) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. . Femoral impaction allografting has been widely used in revision surgery for the acetabulum, and subsequently for the femur. In combination with a primary cemented stem, impaction grafting allows for femoral bone restoration through incorporation and remodelling of the impacted morsellized bone graft by the host skeleton. Cavitary bone defects affecting meta-physis and diaphysis leading to a wide femoral shaft, are ideal indications for this technique. Cancellous allograft bone chips of 1 mm to 2 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a prosthesis dummy of the same dimensions of the definitive cemented stem is driven into the femur to ensure that the chips are very firmly impacted. Finally, a standard stem is cemented into the neo-medullary canal using bone cement. . To date several studies have shown favourable results with this technique, with some excellent long-term results reported in independent clinical centres worldwide. Cite this article: Bone Joint J 2013;95-B, Supple A:92–4

A longitudinal study was done assessing the latest radiographs available in a series of collarless Corail uncemented stems which have reported survival rates of 95% at 20 years. Parameters scored included the degree of “Ghosting” or delamination, the Gruen, the stem fit in the femoral canal and the degree of calcar resorption. Patient and implant demographics were noted. At 3 years the loosening rate was 23% reaching 64% at 6 years after the index procedure. It was present in all age groups, with a peak in the 24 to 49 year age group. Males and females had the same occurrence. When it was present this was always in zone 1. It was present in 6% of patients in zone 7, but then always associated with zone 1 changes. High and standard off-set stems had the same loosening rates. The looser fit of the stem the higher the incidence of loosening. There was no correlation to the type of bearing surface or the degree of calcar resorption. Those patients with a BMI of 25 – 35 had lower loosening rates compared to those with higher or lower BMI's. We postulate that cancellous bone on-growth onto the hydroxyapatite coating associated with loading flexural micro-motion leads to hydroxyapatite being pulled off the smooth stem substrate in zone 1. Progressive delamination of the hydroxyapatite then occurs. The triple-tapered design though imparts continued stability. We report high loosening rates in the Corail stem and suggest a mechanism for its development

We describe the results at five years of a prospective study of a new tri-tapered polished, cannulated, cemented femoral stem implanted in 51 patients (54 hips) with osteoarthritis. The mean age and body mass index of the patients was 74 years and 27.9, respectively. Using the anterolateral approach, half of the stems were implanted by a consultant orthopaedic surgeon and half by six different registrars. There were three withdrawals from the study because of psychiatric illness, a deep infection and a recurrent dislocation. Five deaths occurred prior to five-year follow-up and one patient withdrew from clinical review. In the remaining 51 hips the mean pre-operative Oxford hip score was 47 points which decreased to 19 points at five years (45 hips). Of the stems 49 (98%) were implanted within 1° of neutral in the femoral canal. The mean migration of the stem at five years was 1.9 mm and the survivorship for aseptic loosening was 100%. There was no significant difference in outcome between the consultant and registrar groups. At five years, the results were comparable with those of other polished, tapered, cemented stems. Long-term surveillance continues

Aims

When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results.

Standard practice in revision total hip replacement (THR) for periprosthetic fracture (PPF) is to remove all cement from the femoral canal prior to implantation of a new component. This can make the procedure time consuming and complex. Since 1991 it has been our practice to preserve the old femoral cement where it remains well fixed to bone, even if the cement mantle is fractured, and to cement a new component into the old mantle. We have reviewed the data of 48 consecutive patients, treated at our unit between 1991 and 2009, with a first PPF around a cemented primary THR stem where a cement in cement revision was performed. 8 hips were revised to a standard length stem, 39 hips to a long stem & 1 patient had the same stem reinserted. All fractures were reduced and held with cerclage wires or cables and four had supplementary plate fixation. Full clinical and radiographic follow up was available in 38 patients & clinical or radiographic follow up in a further 6 patients. The other 4 patients. without follow up but whose outcome is known, have suffered no complications and are pain free. Of the remaining 44 patients, forty-two went on to union of the fracture and two have required further surgery for non-union. One patient has ongoing undiagnosed hip pain. Our long term experience with cement in cement revision for periprosthetic femoral fractures shows that this is a viable technique with a low complication rate and high rate of union (95%) in what is generally regarded as a very difficult condition to treat

Aims

The Exeter short stem was designed for patients with Dorr type A femora and short-term results are promising. The aim of this study was to evaluate the minimum five-year stem migration pattern of Exeter short stems in comparison with Exeter standard stems.

Using radiography and computer tomography (CT) we studied the morphology of 83 hips in 69 Caucasian adults with osteoarthritis secondary to developmental dysplasia of the hip (DDH). A previously published series of 310 hips with primary osteoarthritis was used as a control group. According to the Crowe classification, 33 of the dysplastic hips were graded as class I, 27 as class II and 23 as class III or class IV. The intramedullary femoral canal had reduced mediolateral and anteroposterior dimensions in all groups compared with the control group. Only in Crowe class II hips was the femoral neck-shaft angle increased. The proximal femur had more anteversion in all the developmental dysplasia of the hip groups, ranging from 2° to 80°. Templated measurement of acetabular dimensions for plain radiography closely matched measurements taken by CT. The results of our study confirm the observations previously confined to the Japanese population

The purposes of this study were to review retrospectively the 10-year outcome of cementless total hip arthroplasty (THA) using an active robot system in the femoral canal preparation for an anatomic short stem and navigation in the cup placement through a mini incision posterior approach. We reviewed all patients who underwent THA with this procedure in 53 hips between 2004 and 2007. There were no intraoperative fracture nor navigation- or robotic-related complications. All implant sizes were same as planned ones. All cases were followed up at least two years and all implants showed bone ingrowth stable according to the Engh's criteria. After then, six patients died of unrelated causes. Two patients (three hips) could not come to the 10-year follow-up examination. The remaining 44 hips were followed for 10 to 12 years (11 years on average). There is no dislocation. The average JOA hip score improved from 48 preoperatively to 96 at the final examination. On the postoperative x-ray measurements, the average cup radiographic inclination was 39° and the radiographic anteversion was 14°. There was no stem which showed more than 2° of varus or valgus alignment. There was no case who showed more than 5mm of limb length discrepancy. Postoperative CT images of 38 hips were obtained at 2 weeks. After matching the coordinates of the pelvis and femur with the preoperative planning, we got very small differences in alignment parameters between the measured values and the planed ones. The difference differences between the plan and measured values were −0.1° in cup inclination, −1.4° in cup anteversion, stem 0.5° in coronal alignment, 0.6° in stem sagittal alignment, and −1.6° in stem anteversion, respectively. We conclude that our robotic femoral preparation for a short anatomical stem and navigated cup placement thru a mini-posterior approach was safe and feasible without affecting the accuracy of the procedure. There were no long term adverse effect of the procedure

When inserting a femoral stem, surgeons make use of many visual and tactile cues to be sure that the implant is correctly sized and well-seated. One such cue is the change of pitch that can be heard when the final femoral broach is inserted. This is known to be important, but has not been widely studied. We set out to analyse the sounds produced during femoral broaching and implant fixation, and to discover whether the absence of these sounds could predict a poor fixation. We recorded the sound of femoral broaching and definitive implant insertion, for twenty un-cemented Corail total hip replacements. Procedures were performed by the same surgeon, in the same theatre. The recordings were visualised using audio editing software, and a Fast Fourier Transform was used to identify the dominant audio frequencies. In 19 of the 20 cases, the final strikes of the final femoral broach displayed a distinctive pattern, with the most prominent frequencies being harmonics (multiples of a fundamental frequency) which had a wavelength directly related to the length of the femoral canal. This contrasts with initial strikes, where multiple unrelated frequencies were present. Postoperative radiographs were examined by two surgeons independently, to assess implant sizing and positioning. The one case, in which the harmonic pattern was not observed, was found on radiographs to be an undersized, varus malpositioned implant. We demonstrate that a characteristic frequency pattern is present when impacting cancellous bone with a well-sized and well-placed femoral broach. When the pattern was absent, the broach and implant were undersized and malpositioned. We hypothesise that this pattern arises when broach and femur are vibrating as one, indicating adequate contact with, and compression of, cancellous bone

The removal of well-fixed bone cement from the femoral canal during revision of a total hip replacement (THR) can be difficult and risks the loss of excessive bone stock and perforation or fracture of the femoral shaft. Retaining the cement mantle is attractive, yet the technique of cement-in-cement revision is not widely practised. We have used this procedure at our hospital since 1989. The stems were removed to gain a better exposure for acetabular revision, to alter version or leg length, or for component incompatibility. We studied 136 hips in 134 patients and followed them up for a mean of eight years (5 to 15). A further revision was required in 35 hips (25.7%), for acetabular loosening in 26 (19.1%), sepsis in four, instability in three, femoral fracture in one and stem fracture in one. No femoral stem needed to be re-revised for aseptic loosening. A cement-in-cement revision of the femoral stem is a reliable technique in the medium term. It also reduces the risk of perforation or fracture of the femoral shaft

Aims

Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon.

Aims

The purpose of this study is to report our updated results at a minimum follow-up of 30 years using a first generation uncemented tapered femoral component in primary total hip arthroplasty (THA).