Can a Conical Implant Successfully Address Complex Anatomy in Primary THA? Radiographs and Hip Scores at Early Followup

Single-Taper Conical Tapered Stem in Total Hip Arthroplasty for Primary Osteoarthritis: A Comparative Long-Term Registry Evaluation

Background/Objectives: Single-taper conical tapered stems (STCTSs) are possible options for femoral reconstruction in THA performed for primary osteoarthritis, but outcomes are poorly ascertained. A specific STCTS in THA performed for primary osteoarthritis was investigated and compared to a control group including all the other cementless stems, aiming to assess the following: (1) the survival rates of the two cohorts and the hazard ratios for failure; (2) the survival rates and the hazard ratios for failures for stem failure, stem aseptic loosening, and periprosthetic fracture. Methods: A regional arthroplasty registry study evaluating a specific STCTS in THA performed for primary osteoarthritis was designed. A control group including all the other cementless stems was considered. Results: In total, 1773 STCTSs were compared to 37,944 cementless stems. The cumulative survivorship of the STCTS cohort was 95.6% at 10 years and 92.7% at 15 years, which was not different to the control group (p = 0.252). After age stratification, the hazard ratio for STCTS failure was not different to the control group. With stem revision as the endpoint, the STCTS cohort outperformed the control group (at 10 years, 98% versus 96.8%; p < 0.001). The STCTSs achieved better survival rates in females <65 years (p = 0.023). With stem aseptic loosening as the endpoint, the survival rates did not differ between the two cohorts (p = 0.085), as well as the adjusted hazard ratios (p = 0.264). With periprosthetic fracture as the endpoint, the survival rates were better for the STCTSs (p < 0.001). Conclusions: STCTSs in THA for primary osteoarthritis provided dependable long-term outcomes, not inferior to all the other cementless stems with various designs.

Usefulness of non-surgical treatment without weight bearing restriction versus surgical treatment for maintaining activities of daily living in patients with peri-prosthetic femoral fractures

PURPOSE

Non-surgical treatment without weight-bearing restriction, even in the early post-injury phase, may have a favourable effect on the activities of daily living (ADLs) in elderly patients with peri-prosthetic femoral fractures (PFFs). This study aimed to assess the effectiveness of surgical and non-surgical treatments for PFFs in terms of ADL maintenance and clinical safety.

METHODS

This retrospective cohort study included 44 patients with PFFs proximal to the stem fixation site without stem loosening. Rehabilitation with weight bearing was initiated after internal fixation of the fracture site in the surgical group (n = 12) and immediately after the injury in the non-surgical group (n = 32). Clinical and radiological outcomes, including time until the first weight-bearing exercise, time until independent walking, ADL deterioration, and bone union rate, were compared between groups. Independent risk factors for ADL deterioration were also evaluated.

RESULTS

The time until first weight-bearing exercise was shorter and the ADL deterioration rate was smaller in the non-surgical group than in the surgical group (8.8 ± 9.2 vs. 21 ± 13 days, P = 0.004; 6.2% vs. 12.5%, P = 0.04, respectively). Bone union rates were similar between groups (91% vs. 83%, P = 0.42), and aseptic loosening of the stem was not observed. Time until first weight-bearing exercise was identified as an independent risk factor for ADL deterioration (odds ratio, 1.13; 95% confidence interval, 1.01-1.26; P = 0.03).

CONCLUSION

Non-surgical treatment of PFFs proximal to the stem fixation site without stem loosening, which does not restrict early weight-bearing exercise after injury, is an effective and safe treatment procedure that maintains ADL performance in elderly patients.

The Wagner Cone Stem for Atypical Femoral Anatomy in Total Hip Arthroplasty: A Report of 320 Cases with Minimum 5-Year Follow-up

BACKGROUND

The Wagner Cone Prosthesis was designed to address complex femoral deformities during total hip arthroplasty (THA), but its mid-term component survivorship and functional outcomes remain undetermined. The objectives of this study were to determine the implant survivorship, patient satisfaction, functional outcomes, osseointegration as seen radiographically, implant subsidence, and complications of THA using the Wagner Cone Prosthesis stem at intermediate-term follow-up.

METHODS

This study involved 302 patients with proximal femoral deformities, including developmental hip dysplasia and Legg-Calvé-Perthes disease, who underwent a total of 320 primary THAs using the Wagner Cone Prosthesis. The average age at the time of surgery was 49.4 ± 14.5 years (range, 18.8 to 85.6 years). Patient satisfaction was recorded using a self-administered questionnaire assessing satisfaction in 4 domains. The University of California at Los Angeles (UCLA) activity score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score (OHS), the Forgotten Joint Score (FJS), radiographic outcomes, and complications were recorded. The mean follow-up time was 10.1 years (range, 5.2 to 15.5 years).

RESULTS

Survivorship of the Wagner Cone Prosthesis was 98.7% (95% confidence interval [CI]: 97.2% to 100%) with stem revision as the end point and 95.8% (95% CI: 93.5% to 98.2%) with reoperation for any reason as the end point at 10 years postoperatively. In total, 3 stems were revised: 2 for infection and 1 for chronic hip dislocation. The median patient satisfaction score was 95 (interquartile range [IQR], 80 to 100), median UCLA score was 6 (IQR, 6 to 7), median WOMAC score was 18 (IQR, 16 to 22), median OHS was 40 (IQR, 36 to 47), and median FJS was 80 (IQR, 76 to 88) at the time of final follow-up. All Wagner Cone stems that were not revised showed radiographic evidence of osseointegration, with a mean stem subsidence of 0.9 ± 0.8 mm at the most recent follow-up.

CONCLUSIONS

The use of the Wagner Cone Prosthesis stem in patients with complex femoral anatomy undergoing primary THA is associated with excellent component survivorship, high levels of patient satisfaction, good functional outcomes, and reliable osseointegration with minimal stem subsidence as seen on radiographs at intermediate-term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Clinical and radiographic outcomes of long monoblock, hydroxyapatite-coated stem in revision hip arthroplasty with extended trochanteric osteotomy: a multicenter study

BACKGROUND

The distally fixed stem used in revision total hip arthroplasty (rTHA) with extended trochanteric osteotomy (ETO) is subject to periprosthetic fracture, stem subsidence, and stress shielding. The prospective multicentric study aimed to assess the clinical and radiographic outcomes, and complications of using the Corail revision stem in rTHA with ETO.

METHODS

Sixty-four patients undergoing rTHA with ETO using the Corail revision stem between 2019 and 2020 were enrolled in the study. We performed a postoperative follow-up of the patient and obtained radiographs and Harris hip scores (HHSs). These results were used to analyze ETO union, Engh scores, bone remodeling, stem stability and hip function.

RESULTS

The mean follow-up duration was 34 months (range 23-41). Sixty-two patients who underwent ETOs achieved complete healing at the final follow-up. Fifty-nine hips had bony ingrowth from the osteotomy fragment to the stem without radiolucent lines. The postoperative Engh score was 21.3 ± 3.59 (range 15.5-27.0). Forty-three hips had regeneration in the proximal femur. Two patients had transient thigh pain postoperatively. The postoperative HHS improved from 40.7 ± 16.67 (range 0-67) preoperatively to 82.1 ± 6.83 (range 73-93).

CONCLUSION

Corail revision stems are a viable and reliable option in rTHA with ETO. This stem had excellent clinical and radiographic outcomes, resulting in a high rate of ETO union and stem survival. The revision stem enabled restoration of proximal bone stock in femurs with prerevision bone defects, which were prepared for the next revision operation. Level of evidence Level IIb, Prospective self-control study.

Single-taper conical tapered stem in total hip arthroplasty for developmental dysplasia of the hip: A long-term evaluation

INTRODUCTION

Conical tapered stems may be useful implants to manage the reconstruction of complex dysplastic anatomies. The aims of this paper were to assess: 1) the preoperative CT features of the dysplastic femurs; 2) survival rates, complications and reasons for revision; 3) the clinical outcomes; 4) the radiographic outcomes of single-taper conical stems in dysplasia (defined as center edge angle < 20°) at a long-term follow-up.

HYPOTHESIS

Monoblock conical stem provides a 10-year survival rate of at least 95%, with excellent clinical outcomes and bony ingrowth.

MATERIALS AND METHODS

In total, 100 THAs in 85 patients (15 bilateral cases) were enrolled. The average age of the patients at surgery was 50.9±11.5 years. Assessment of the native femoral morphology was performed using CT-scan, coronal (neck-shaft angle, offset, center of rotation position) and axial parameters (anteversion, mediolateral and anteroposterior femoral diameters). Clinical (HHS score) and radiological (osseointegration, subsidence and offset reconstruction) outcomes were evaluated at the last available follow-up.

RESULTS

The mean follow-up was 9.34±5.61 years. Severely distorted anatomies from Crowe I to Crowe IV were included, with a mean canal flare of 4.3 and a mean femoral antetorsion of 34°. The survival rates were stable at long-term (98.9% at 10 and 15 years): no aseptic loosening occurred. The mean postoperative HHS was 89.8±6.8 points. Ninety-nine percent of the stems showed bone ingrowth, from 6 months to the last available follow-up. Subsidence occurred in 18% of the cases (mean value: 2.5mm, range: 1-6mm) in the first month, with subsequent stabilization. A mild proximal stress shielding occurred in 28% of the THAs. Radiolucent lines were detected in the 8% of the cases. There was a postoperative loss of offset in 12% of the cases.

DISCUSSION

Conical stems in dysplastic hips achieved bony ingrowth at long-term outcome, even in complex anatomies. Subsidence, proximal stress shielding and imperfect offset restoration may occur with this implant.

LEVEL OF PROOF

IV; retrospective study.

The use of a standard-length conical tapered stem in hip revision arthroplasty to address Paprosky type I-II femoral defects: a prospective study of 87 patients

INTRODUCTION

Low-grade femoral defects in revision total hip arthroplasty (rTHA) might be preferably treated with a primary implant. Almost no previous study reported the use of standard-length conical tapered (SLCT) stems in these cases. We analyzed a series of cases using a SLCT stem in rTHA with Paprosky type I-II femoral defects. The purpose of the study was to determine clinical and radiographic outcomes in this series of rTHA.

MATERIALS AND METHODS

We prospectively followed 87 patients undergoing a femoral component rTHA: 53 Paprosky type I and 34 type II femoral defects. Patient-reported measures (Oxford Hip Score, EQ-5D, VAS pain during rest and activity) were administered at baseline, 1 and 2 years post-operatively. Radiographic subsidence overtime was scored. Kaplan-Meier curves were used to evaluate the subsidence over time, the complication-free survival, and the implant survivorship with reoperation and stem revision as endpoints.

RESULTS

The mean follow-up was 72.5 (SD ± 23.9) months. All PROMs significatively improved over time. The average subsidence was 2.8 (SD ± 3.2), 3.6 (SD ± 4.4), and 4.0 (SD ± 4.9) mm at 4, 12, and 24 months respectively. 6 stems had subsidence > 10 mm. The survival without complication was 0.85 (95% CI 0.94-0.77), while the implant survival without reoperation was 0.83 (95% CI 0.95-0.72). The overall stem survival rate was 93.7% (95% CI 0.91-0.97) at 2 years.

CONCLUSION

The use of a SLCT stem in rTHA with Paprosky type I-II femoral defects demonstrated good survival with low subsidence rates during the first 2 years after surgery. Surgeons should consider the use of this primary prosthesis as a potential treatment during stem revision in cases with limited femoral bone loss.

Midterm results of titanium conical Wagner stem with challenging femoral anatomy: Survivorship and unique bone remodeling

BACKGROUND

Complex anatomy of the proximal femur makes total hip arthroplasty (THA) more challenging. Short, straight, fluted and conical titanium stem like the Wagner Cone can be helpful to address small femoral canal, increased femoral neck version, important leg length discrepancy or proximal femoral deformity. The outcome in these patients is less assured and associated with high rate of complications. Therefore, we did a retrospective study aiming to answer: 1) can the Wagner Cone stem provide acceptable mid- to long-term implant survivorship; 2) help minimizing perioperative adverse events; 3) produce favorable clinical outcome measured by WOMAC score; and 4) be associated with a favorable radiographic femoral bone remodeling at the last follow-up?

HYPOTHESIS

Wagner Cone stem is an advantageous solution for the distorted proximal femur in complex THA.

PATIENTS AND METHOD

Our cohort was derived from the patient registries where medical records of 88 patients (103 hips) who underwent primary THA using the Wagner prosthesis were retrospectively reviewed. Then, data was analyzed for patients' demographics and surgical data, and comparing preoperative, immediate postoperative and last follow-up data. Eleven patients (12 hips) were excluded (7 hips followed up less than 2 years or lost to follow-up, 3 hips that had the Wagner stem for revision and 2 Wagner stems inserted for periprosthetic fracture). This left 77 patients (91 hips) with Wagner cone stems implanted for more than 2 years between March 2003 and February 2017 by 7 surgeons in 3 academic hospitals. Implant revision, reoperations, WOMAC score and radiographic analyses were recorded at last follow-up.

RESULTS

After a mean follow-up of 7.8 (range, 2.0-16.2) years, Wagner stem survivorship was 98.9% (95% CI: 94 to 100%) with one (1.1%) stem revision for failure of osteointegration. Five (5.5%) acetabular revisions, one for aseptic loosening, 2 for adverse reaction to metal debris and 2 for infection. One (1.1%) sciatic neuropathy and 4 (4.4%) intraoperative fractures were encountered. The mean WOMAC score was 90.5±11.4 (59-100). Radiographic analysis showed clear signs of stem osseointegration and hypertrophic bone remodeling in 82 cases (92.1%).

CONCLUSIONS

Used in complex cases with proximal distorted femurs, the Wagner Cone stem demonstrated a low complication rate, a high-rate consistent adaptive bone remodeling, excellent clinical results, and midterm survival. It is a safe, reliable and advantageous option in complex primary THA. However, the contribution of the underlying cause of the secondary osteoarthritis on the long-term survival of the stem remains to be demonstrated.

LEVEL OF EVIDENCE

IV; retrospective study.

Clinical and radiographic outcomes of primary total hip arthroplasty with the revelation hip system using density mapping

The Revelation Hip System is a cementless stem with a lateral flare concept. Stable fixation is achieved by fitting the stem to the medullary cavity of the proximal lateral femoral cortex. Patients who have undergone total hip arthroplasty using the Revelation Hip System show good postoperative clinical and radiographic outcomes. However, to the best of our knowledge, no study has reported the relationship between stem fitting and clinical or radiological outcomes after the surgery. In the present study, we investigated the relationship between stem fitting and clinical or radiological outcomes after total hip arthroplasty (THA) using the Revelation Hip System. In this study, 28 hips of 26 patients who were treated with the Revelation Hip System for osteoarthritis, osteonecrosis of the femoral head, rheumatoid arthritis, and rapidly destructive coxarthropathy and were followed up for > 5 y were enrolled. These patients were divided into two groups, including the rest fit group (11 hips, group R) and the control group (17 hips, group C), according to the results of the density mapping analysis. In group R, the lateral side of the stem fits on the medullary cavity of the proximal lateral femoral cortex, while in group C, the lateral side of the stem did not fit. Radiographic results showed no significant differences between the groups in terms of stem alignment, subsidence, and stress shielding around the cup. The incidence of stress shielding around the stem in zone 7 was not significant but tended to be higher in group R than in group C (p = 0.052). Clinical outcomes showed no significant differences between group R and group C in terms of the Harris hip score, the Japanese Orthopaedic Association (JOA) score, and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) total score. However, pain complaints that were assessed by patient-reported outcomes using the 36-Item Short Form Health Survey (SF-36) bodily pain and vitality subscales and the JHEQ pain subscale were significantly higher in group R than in group C at the final follow-up. These results suggest that some patients had pain complaint even if the stems were inserted as per the concept after THA with the Revelation Hip System.Trial Registration911.

Outcome of the Wagner Cone femoral component for difficult anatomical conditions during total hip arthroplasty

PURPOSE

Total hip arthroplasty (THA) in patients with small or unusual proximal femoral anatomy is challenging due to sizing issues, control of version, and implant fixation. The Wagner Cone is a monoblock, fluted, tapered stem with successful outcomes for these patients; however, there is limited information on subsidence, a common finding with cementless stems.

METHODS

We retrospectively reviewed our cases using the modified Wagner Cone (Zimmer, Warsaw, IN) implanted over a 13-year period (2006-2019) in patients with small or abnormal proximal femoral anatomy. We performed 144 primary THAs in 114 patients using this prosthesis. Mean follow-up was 4.5 ± 3.4 years (range, 1-13 years). Common reasons for implantation were hip dysplasia (52%) and osteoarthritis in patients with small femoral proportions (22%). Analysis of outcomes included assessment of stem subsidence and stability.

RESULTS

Survival was 98.6% in aseptic cases; revision-free survival was 97.9%. Femoral subsidence occurred in 84 cases (58%). No subsidence progressed after 3 months. Of those that subsided, the mean distance was 2.8 ± 2.0 mm. There was less subsidence in stems that stabilized prior to six weeks (2.2 ± 1.4 mm) compared to those that continued until 12 weeks (3.9 ± 1.6, p = 0.02). Harris Hip, UCLA, and WOMAC scores significantly improved from pre-operative evaluation (p < 0.001*, p < 0.003*, p ≪ 0.001*); there was no difference in outcome between patients with and without subsidence (p = 0.430, p = 0.228, p = 0.147).

CONCLUSION

The modified Wagner Cone demonstrates excellent clinical outcomes in patients with challenging proximal femoral anatomy. Subsidence is minor, stops by 3 months, and does not compromise clinical outcome.

Which stem in total hip arthroplasty for developmental hip dysplasia? A comparative study using a 3D CT-based software for pre-operative surgical planning

Background

Stem choice in total hip arthroplasty (THA) for hip dysplasia is still controversial. The aims of the study were to evaluate (1) which stem design provided the highest percentage of adequate reconstructions in THA for dysplasia and (2) any correlation between the reconstructions provided by the stems and the native femoral morphology.

Materials and methods

150 CT scans including 200 adult dysplastic hips were randomly selected. Using the 3D CT-based software Hip-Op for surgical planning, the native hip anatomy was studied. Then, a single wedge tapered stem, an anatomical stem and a conical tapered stem were simulated in every hip. An adequate reconstruction of hip biomechanics was obtained when combined anteversion, offset restoration, coronal and sagittal tilt, canal filling and leg lengthening were inside the normal ranges.

Results

Conical stems achieved the highest percentage of adequate reconstructions (87%, p < 0.0001). The anatomical stem was the worst performer. Single wedge and anatomical stem acceptability was mainly influenced by the combined anteversion. Stem anteversion was correlated with the femoral anteversion (fair correlation), the calcar femorale (fair) and the mediolateral femoral diameter at isthmus (poor). When the femoral anteversion was ≥ 25°, combined anteversion was very acceptable for the conical stem (99.2%), whereas the rate of acceptable combined anteversion for the single wedge tapered stem was 71.4%, and that for the anatomical stem was 51.6% (p < 0.0001).

Conclusions

Stem choice in developmental hip dysplasia is mainly driven by appropriate combined anteversion, which is dependent on the coronal and axial femoral morphologies. As a rule of thumb, tapered stems are adequate when femoral anteversion is < 25°; conical stems should be adopted for higher anteversions.

Level of evidence

IV.

Short-term results of total hip arthroplasty using a tapered cone stem for patients with previous femoral osteotomy

PURPOSE

In total hip arthroplasty (THA) for patients with previous femoral osteotomy, we hypothesized that a tapered cone stem may be an option due to the altered morphology of the proximal femur. The purpose of this study was to assess the short-term results of THA after femoral osteotomy using a tapered cone stem, and to identify issues that require further attention.

METHODS

Twenty-two hips in 21 consecutive patients who underwent THA after femoral osteotomy using a Wagner Cone tapered cone stem were retrospectively reviewed, with a mean follow-up period of 34.4 (range, 24-50) months. Clinical information was obtained from medical records. On preoperative radiographs, the Dorr type was classified based on the anteroposterior cortical index. On postoperative radiographs, the degree of stem subsidence and the stem location with the highest canal fill ratio were assessed.

RESULTS

The mean Harris hip score significantly improved from 55.2 at baseline to 84.8 at final follow-up. Radiologically, stem subsidence (>3 mm) was observed in seven hips, and it stabilized within 1 year after THA in all cases. In five of seven hips with stem subsidence, the highest postoperative canal fill ratio was observed in the distal third of the stem. The proportions of males and Dorr type A were significantly higher among hips with stem subsidence than among those without. During the follow-up period, no hips showed implant loosening or required revision surgery.

CONCLUSIONS

The occurrence of stem subsidence should be noted when using Wagner Cone stems for Dorr type A femurs after femoral osteotomy.

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.

Total hip arthroplasty for dysplastic coxarthrosis using a cementless Wagner Cone stem

Background

Total hip arthroplasty (THA) is currently the best surgical option for hip osteoarthritis secondary to developmental hip dysplasia (DDH); it may be extremely challenging, because of the hypoplasic proximal metaphysis, pathological anteversion, and excessive cervico-diaphyseal angle of the neck at the femoral side. The purpose of this retrospective study was to evaluate the long-term survival and clinical and radiological results of Conus uncemented stems, implanted in patients affected by hip osteoarthritis with Crowe not-type IV secondary to DDH.

Material and methods

We identified 100 consecutive THAs performed for DDH in 63 women and 24 men, with an average age of 53 years in a single center. Thirteen patients underwent bilateral hip replacement. The patients’ mean body mass index was 29.8 kg/m² (range 27.1–35.6 kg/m²). The main indications for surgery were severe hip pain and considerable functional impairment: the preoperative Harris Hip Score was 29.5 on average (range 22–61). Radiologically, 8 hips were classified as Crowe I, 43 hips as Crowe II, and 49 hips as Crowe III. In all cases, we implanted the Wagner femoral cone prosthesis using the direct lateral approach; in the attempt to reestablish native hip biomechanics, 66 stems were 135° and 34 were 125°.

Results

The mean follow-up of the study was 11.7 years (range 2.2–21.8 years). Harris Hip Score increased to a mean value of 71.5 points (range 52–93 points). Radiographic evaluation demonstrated osteointegration of the implant with stable bone growth observed at the stem–endosteum interface; signs of bone readaptation and thinning of the femoral calcar were present in nine hips. None of the patients underwent revision for septic or aseptic loosening of the stem; none sustained a periprosthetic fracture.

Conclusions

This study confirms the theoretical advantages that suggest the choice of the Wagner cone when technical difficulties during prosthetic surgery are expected owing to abnormal proximal femoral anatomy.

Level of evidence

Level IV, retrospective case study

Cementless ceramic-on-ceramic total hip arthroplasty in post-traumatic osteoarthritis after acetabular fracture: long-term results

INTRODUCTION

Total hip arthroplasty (THA) is the standard procedure for post-traumatic osteoarthritis (OA) of the hip after acetabular fracture. However, it is not as simple as a primary THA, challenging the surgeon with anatomical deformity and intra and postoperative complications. In the current literature, there is a lack of studies reporting long-term results. May ceramic-on-ceramic (CoC) bearings provide good clinical and radiological outcomes at a long-term follow-up in patients undergoing THA following acetabular fracture?

MATERIALS AND METHODS

We retrospectively analyzed 68 patients (mean age 47 years [range 22-75)] who underwent cementless modular neck stem THA, all implants CoC bearings (50 previously operatively treated and 18 non-operatively treated) after a specific CT study protocol at our Institute since 2000-2008. Clinical outcomes, prosthetic components' osseointegration, survival rate, and reasons for revision were analyzed. Minimum clinical and radiological follow-up was 10 years.

RESULTS

HHS improved significantly after surgery from 37.6 ± 14.1 to 88.4 ± 11.6. 8 revision surgeries were performed, none for infection: we reported 2 stem aseptic loosening, 2 periprosthetic femoral fractures and 4 modular neck fractures. One implant noise (third-generation ceramic coupling) was described. Cup osseointegration was present (according to Moore the presence of at least 3 radiological criteria defines an effective osseointegration) in 67 patients (98.5%). After a 10 years follow-up, survival rate resulted 88.4%, sensibly higher than most of results reported in the current literature.

CONCLUSION

The high survival rate may be related to CoC: no osteolysis and no infections were reported. Also acetabular cup loosening incidence was sensibly lower (1.47%) among loosening rate described by other authors. Clinical and radiological outcomes were decent, probably due to modular prosthesis design. Modular necks are a solution which can help achieving a proper functional reconstruction of the hip (offset, center of rotation), but should be avoided in young and overweight patients because of the high risk of fracture. CoC bearings in THAs in post-traumatic OA after acetabular fracture showed good results despite the fact that specific ceramic-related issues have to be considered.

Modular Fluted Tapered Stems in Aseptic Oncologic Revision Total Hip Arthroplasty: A Game Changer?

BACKGROUND

Modular fluted tapered (MFT) stems are the most frequently used femoral component in revision total hip arthroplasties (THAs). Despite this, no data are available on how they perform in revision THA for oncologic salvage. This is a unique population, often with severe bone loss and prior radiation that extends the limits of uncemented femoral reconstruction. The aims of this study were to evaluate the implant survivorship, radiographic results, and clinical outcomes of MFT stems used for revision oncologic salvage.

METHODS

We identified 17 patients treated initially with primary THA for an oncologic diagnosis (15 primary oncologic, 2 metastatic disease) who underwent subsequent femoral revision with an MFT stem. Mean age at revision was 66 years and 35% of patients were female. Mean follow-up was 4 years. Before revision, 5 of 17 had undergone local radiation.

RESULTS

Ten-year survivorship free from aseptic loosening was 100%. The survivorship free of any reoperation was 76%. There were no femoral component fractures. Three patients were revised for recurrent instability, and 1 patient underwent irrigation and debridement for an acute infection. At most recent follow-up, no patient had radiographic evidence of progressive femoral component subsidence or failure of osteointegration. The mean Harris Hip Score improved from 29 preoperatively to 76 postoperatively (P < .0001).

CONCLUSION

In this series of patients with cancer, many of whom had severe bone loss and/or prior local radiation, being treated with revision THA, there were no revisions for femoral component loosening and no cases of implant fracture.

LEVEL OF EVIDENCE

III.

Total Hip Arthroplasty With a Monoblock Conical Stem in Dysplastic Hips: A 20-Year Follow-Up Study

BACKGROUND

Total hip arthroplasty in patients with hip dysplasia is challenging as a result of complex anatomic deformities in the hip. The aim of the study was to evaluate the survivorship, the clinical and radiographic outcomes of cementless Wagner Cone stem in patients with dysplastic hip.

METHODS

This retrospective study reports on 102 patients (135 hips) who have undergone total hip arthroplasty between 1993 and 1997. The mean age of patients was 51 years (range, 21-73). Minimum follow-up was 20 years. According to the Crowe classification, 38 hips presented dysplasia of grade I, 41 of grade II, 37 of grade III, and 19 of grade IV.

RESULTS

Kaplan-Meier survivorship for aseptic loosening was 97% (95% confidence interval, 94.4-99.6) at 20 years. The average Harris hip score increased from 43.4 points (range, 22-51) to 86.4 points (range, 39-100) (P < .0001) and average Merle d'Aubignè score increased from 8.4 (range, 4-13) to 15 (range, 5-18) (P < .0001); at the last follow-up, average University of California at Los Angeles activity score and visual analog score were 4.53 (range, 1-9) and 1.25 (range, 0-6), respectively; 17% of heterotopic ossification and 19.2% of radiolucency lines around the stem were reported.

CONCLUSION

Monoblock Wagner Cone stem is a reliable option in dysplastic hip with an excellent survivorship and good clinical and radiographic outcome in the long term.

The Hip in Juvenile Idiopathic Arthritis

The hip joint is commonly affected in Juvenile Idiopathic Arthritis (JIA), especially in cases of systemic polyarticular disease. Chronic synovitis of the hip leads to joint destruction, therefore, systemic and local control of the disease is of paramount importance. Non-steroidal anti-inflammatory drugs, Disease Modifying Anti-Rheumatic Drugs (DMARDs), biologics, intra-articular corticosteroid injections, and physical therapy are the mainstay for controlling ongoing inflammation and hip joint contractures. Synovectomy with soft tissue releases is useful in the early stages of the disease, when the joint cartilage is largely preserved. Total joint arthroplasty (THA) is successful in relieving pain, and improving function, ambulation and range of motion in end-stage degenerative arthritis. With improved designs of smaller prostheses and modern bearing couples, it is hoped that the longevity of THA will facilitate a more normal and enduring lifestyle.

Comparison of two different on-shelf femoral stems for Crowe type IV developmental dysplasia of the hip

Objective

This study was performed to evaluate the proximal anatomical compatibility of stems for treatment of Crowe IV developmental dysplasia of the hip (DDH) using a previously developed three-dimensional comparison technique.

Methods

Patients with Crowe IV DDH who underwent computed tomography were retrospectively analyzed. The femoral medullary canals were three-dimensionally reconstructed, and models of cementless modular (S-ROM; DePuy Synthes) and conical (Wagner Cone; Zimmer Biomet) implants were used for virtual implantation. The negative point percentages (NPPs) were applied to verify fitting. The average distance (deviation) and the root mean square of the distance (RMSd) were used to quantify geometric compatibilities.

Results

Four (16.7%) and 12 (50.0%) femoral medullary canals could not be fitted properly with either the modular or conical implant. The NPPs in the distal comparison region were significantly greater in the conical than modular group. The deviation was significantly smaller in the modular than conical group. The RMSd was also significantly smaller in the modular than conical group.

Conclusions

Compared with conical implants, modular implants might be more effectively used in patients with Crowe type IV DDH. However, some Crowe IV DDH femurs with severe deformity cannot be fitted with either of these two on-shelf implants.

Wagner Cone Midterm Survivorship and Outcomes

BACKGROUND

Total hip arthroplasty (THA) in patients with abnormal proximal femoral anatomy requires an individualized treatment approach to prevent complications. Metaphyseal engaging stems in this population risk fracture, size/offset mismatch, and aseptic loosening. The Wagner conical femoral implant is a short diaphyseal engaging femoral stem that could improve treatment success in this difficult patient population.

METHODS

We identified 302 consecutive patients undergoing THA using the Wagner cone femoral prosthesis between January 2010 and January 2017. Clinical, radiographic, and patient-reported outcomes were obtained through chart review and radiographic measurements of postoperative X-rays. We used multivariate analysis to determine predictors of poor outcomes. Kaplan-Meier curves were created to demonstrate implant survivorship with reoperation and revision as endpoints. The average follow-up was 3.2 years, with a minimum of 2 years.

RESULTS

The implant retention survival rate during the 3.2-year study period was 98.7%. The overall reoperation rate was 4.2%, with infection followed by fracture being the most common reasons for reoperation. No patients were revised for aseptic loosening, and no patients were revised for subsidence. The average subsidence was 1.1 mm. The Harris Hip Score improved from 48.6 ± 7.3 (range, 28-64) preoperatively to 86.1 ± 8.5 (range, 66-100) at latest follow-up. The patient-reported satisfaction rate was 98.3%.

CONCLUSION

The Wagner cone femoral prosthesis demonstrated excellent clinical, radiographic, and patient-reported functional outcomes at midterm follow-up. We recommend use of the Wagner cone in THA patients with challenging proximal femoral anatomy, small femoral diameter, or poor metaphyseal bone quality.

Double-tapered conical taper in primary and revision surgery: rationale and short-term follow-up

BACKGROUND:

The new double-conical tapered stem is a novel cementless modular system, which is indicated for both primary and revision surgeries. It has been designed with different angles at the proximal (5°) and distal sections (1° 36') in order to obtain optimal fixation by proximal and distal fit and fill of the femoral canal.

AIM:

The aim of this prospective study was to evaluate the short-term clinical and radiographic outcomes of primary and revision hip surgery with the new double-conical stem.

METHODS:

61 stems were implanted (December 2013 to September 2016) in 42 cases of primary and in 19 cases of revision surgery. The mean age of patients was 64.7 (17-94; standard deviation [SD] 21.9) years.

RESULTS:

The mean body mass index of the patients was 24.6 (17-34.6). In 3 cases of developmental dysplasia of the hip we performed femoral shortening osteotomy. The mean follow-up was 26 (8-40) months. 3 patients died due to causes unrelated to surgery. Postoperative complications included 3 hip dislocations, 2 infections and 1 case of stem explant for metastatic tumour. For all other cases, at the last follow-up radiographs showed no loosening, no radiolucent lines nor subsidence. The mean Harris Hip Score significantly improved from 45 (range 35-58) preoperatively to 87 (range 75-94). Leg length discrepancy was found in 10% of cases but never >1 cm.

CONCLUSIONS:

Radiographic analysis showed the bone-stem contact full at 2 levels of taper. The double-tapered prosthetic stem can therefore be usefully employed both in primary and in revision surgeries.

Modular Fluted Tapered Stems in Aseptic Revision Total Hip Arthroplasty

BACKGROUND

Modular fluted tapered stems have become the most commonly employed category of femoral component in revision hip arthroplasty in North America as a result of favorable early results and simplicity of use. Despite wide adoption, the majority of published data are limited to relatively small series with modest follow-up. The goal of the current study was to determine the success rate and factors associated with success, failure, and complications of the use of modular fluted tapered stems in aseptic revision total hip arthroplasties (THAs) in a large patient cohort.

METHODS

We identified 519 aseptic femoral revisions during which a modular fluted tapered stem was utilized. Clinical outcomes, Kaplan-Meier survivorship, radiographic outcomes, and complications were assessed. The mean age at revision arthroplasty was 70 years, the mean body mass index (BMI) was 29 kg/m, and the mean duration of follow-up was 4.5 years (range, 2 to 14 years).

RESULTS

The mean Harris hip score (HHS) improved significantly from 51 points preoperatively to 76 points at 2 years (p < 0.001). This improvement was maintained at the last follow-up evaluation (mean HHS = 75 points). At the time of the most recent follow-up, 16 femoral revisions had been performed: 6 because of aseptic loosening, 4 because of infection, 3 because of instability, 2 because of periprosthetic fracture, and 1 because of stem fracture. The 10-year survivorship was 96% with revision for any reason as the end point and 90% with any reoperation as the end point. Of the patients who were alive and had not undergone revision at the time of final follow-up, 12 had stem subsidence but all but 1 of these stems had stabilized after subsiding. Postoperative complications were noted in 12% of the cases. Repeat revision due to femoral component loosening was not correlated with the preoperative bone-loss category or patient demographic factors.

CONCLUSIONS

In this large series, femoral revision with a modular fluted tapered stem provided a high rate of osseointegration and sustained improvement in clinical scores at the time of the last follow-up. There was also a high rate of successful implant fixation across all categories of preoperative bone loss and an acceptable rate of complications.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Is there a role for femoral offset restoration during total hip arthroplasty? A systematic review

Benefits of femoral offset restoration during total hip arthroplasty should be the reduction of bearing surfaces wear, implant loosening and dislocation rates. Modular neck stems ensure offset customization but fretting corrosion and catastrophic failures are well-documented complications. Since clinical evidences are needed to substantiate the effectiveness of femoral offset restoration and promote modular neck choice, we systematically reviewed the literature to ascertain whether femoral offset itself has a proven clinical influence: (1) on bearing surfaces wear, (2) implant loosening, (3) and dislocation rates. A systematic literature screening was conducted to find papers dealing with the influence of femoral offset on wear, dislocation and loosening, including articles with conventional radiographic femoral offset assessment and with comparative design. Observational studies, case reports, instructional course lectures, cadaveric and animal studies as well as biomechanical studies, letters to the editor, surgical techniques or technical notes were all excluded. No limits about publication date were supplied but only papers in English were taken into account. Data were extracted into an anonymous spreadsheet. Offset values, dislocation rates, wear rates, follow-up and surgical approaches were all detailed. Ten manuscripts were finally selected. A statistically significant correlation between femoral offset restoration and the reduction of conventional ultrahigh-molecular-weight polyethylene wear was found in two out of three papers investigating this issue, but no correlations were found between femoral offset and dislocation rates or implant loosening. Femoral offset modification influences ultrahigh-molecular-weight polyethylene liners wear, but no correlation was found with dislocation rates or implant loosening. Advantages on wear can be counterbalanced by the use of hard bearing surfaces or highly cross-linked polyethylene liners, besides the availability of larger femoral heads improving implant stability further reduces the importance of femoral offset restoration by means of modularity. We believe that efforts in restoring femoral offset during total hip arthroplasty do not translate into tangible clinical profits and consequently, we do not advise the routinely usage of modular neck stems in total hip arthroplasty.

LEVEL OF EVIDENCE

level III, systematic review of case-control studies.