Total hip arthroplasty in developmental hip dysplasia using cementless tapered stem. Results after a minimum 10-year follow-up

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.

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.

Battle of the titans: Survivorship analysis of the 3 most common types of uncemented femoral stems used across national registries

Background

Although many institutions utilize uncemented stems as routine in performing total hip arthroplasty (THA), many surgeons continue to rely on outcomes reported in the literature in the form of small cohorts and patient series when analyzing survivorship for specific implants. The purpose of this study was to identify and analyze the survivorship of the 3 most common uncemented stem types (as opposed to brands) used across multiple national joint registries.

Methods

A review of data available from all national joint registries was carried out in July 2022. Analysis of each individual registry and classified uncemented implants into the seven different uncemented stem types. The 3 most common stem types were identified, and average cumulative revision rates calculated. Metal on metal bearings surface implants were excluded from this study due to high revision rates across all implant types.

Results

Our detailed review identified 6 out of 13 (NJR, AOANJRR, LROI, EPRD, MARCQI and the NZJR) international registries reporting implant specific survivorship on uncemented femoral stems; including 960,328 uncemented stems across all registries. The most common type of stem used was type 3c, accounting for 61% (583,724), followed by type 1 stems with 23% (217,897) and type 2 stems with 8% (79,257). Cumulative revision rates at 13 years follow-up for these stems ranged from 6.9% to 7.9%.

Conclusion

Although all stem types have comparable revision rates across all registries, the most common uncemented stem reported was the type 3c, tapered rectangular fully coated stem. Furthermore, out of all type 3c, the Müller design philosophy with full hydroxyapatite coating seems to be the most sought after worldwide. In this study we can conclude, thus far, that there does not appear to clinical or statistical differences in revision rates between the different stem types.

Level of evidence

III.

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.

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.

Minimum 10-Year Follow-Up of Total Hip Arthroplasty With a Collarless Triple-Tapered Polished Cemented Stem With Line-to-Line Implantation Using a Direct Anterior Approach

BACKGROUND

The Trilliance stem (B. Braun-Aesculap, Tuttlingen, Germany), a novel collarless triple-tapered polished stem, was introduced in 2009. The aim of this study is to evaluate the long-term clinical and radiological results of the Trilliance stem with line-to-line implantation in primary total hip arthroplasty using a direct anterior approach.

METHODS

A consecutive retrospective series of 130 patients (151 hips) who underwent total hip arthroplasty between February 2009 and August 2011 were evaluated for a minimum of 10 years. Of these, 87.4% had a diagnosis of secondary osteoarthritis based on developmental hip dysplasia. Clinical and radiological results, complications were evaluated and survival analysis was performed.

RESULTS

The mean follow-up was 10.7 years (range, 10.0-12.1). Thirteen hips (13 patients, 6.8%) were lost to follow-up. Adequate cementation (Barrack grade A) was achieved in 136 hips (93.8%) 1 week post-operatively. Nearly all (144 hips, 99.3%) had been inserted within the range of 3°. No significant differences were identified between high- (≥30 procedures/year) and low- (<30 procedures/year) volume surgeons. The Kaplan-Meier survival analysis with revision of the femoral component for aseptic loosening, revision of the femoral component for any reason and revision of either component for any reason as the end points, cumulative survivorship was 100.0%, 97.6% (95% confidence interval (CI) 95.4-100.0) and 96.5% (95% CI 93.8-99.3) at 10 years, respectively.

CONCLUSION

The Trilliance stem with line-to-line implantation using a direct anterior approach has an excellent clinical and radiological outcome at a minimum of 10 years' follow-up.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Mid-term outcomes of the Wagner Cone Prosthesis™ stem for developmental dysplasia of the hip: minimum two year follow-up

PURPOSE

Treatment of symptomatic developmental dysplasia of the hip (DDH) requires a technically demanding total hip arthroplasty (THA) reconstruction. In patients with DDH, prostheses can be difficult to implant and often face the risk of fracture, mismatch, and loosening. The Wagner Cone Prosthesis™ is a tapered, conical stem which can improve treatment success in this population. We look at midterm survivorship and outcomes of THA for DDH using the Wagner Cone Prosthesis™.

METHODS

We retrospectively analyzed 28 patients (33 hips) with DDH undergoing THA using the Wagner Cone Prosthesis™ between January 2008 and January 2020. Ten, nine, and fourteen included patients were classified as Hartofilakidis A, B, and C, respectively. Survivorship according to Kaplan-Meier analysis was the primary outcome, with re-operation and revision as endpoints. The Oxford hip score (OHS) was used to assess clinical outcome. We used multivariate analysis to determine predictors of poor outcomes. The average follow-up was 4.6 years, with a minimum of two years.

RESULTS

Kaplan-Meier survivorship over the 13-year study period was 93.9 ± 4.2% for all-cause revision as an endpoint and 96.9 ± 3.1% for stem revisions only. The overall reoperation rate was 6.1%, with periprosthetic fracture and dislocation being reasons for re-operation. No patients were revised for aseptic loosening, and no patients were revised for subsidence. OHS improved from 19.3 ± 9.6 (4-39) pre-operatively to 37.6 ± 8.4 (19-48) at latest follow-up (p < 0.05).

CONCLUSION

In patients with DDH, THA with the Wagner Cone Prosthesis™ demonstrates excellent clinical, radiographic, and patient-reported functional outcomes at midterm follow-up.

Risk factors of dislocation after total hip arthroplasty in patients with developmental dysplasia of the hip

PURPOSE

Dislocation following total hip arthroplasty (THA) is a well-known complication. However, there is little data on its rate and predictors in patients with developmental dysplasia of the hip (DDH). The current study is aimed to determine the rate and specific risk factors of dislocation following THA in DDH patients.

METHODS

All the medico-surgical records of primary THAs from January 2014 to January 2019 were retrospectively reviewed. They were categorized into three main groups: primary OA, DDH, and others. Pre-operative and post-operative radiographs, past medical and surgical history, and surgical notes were reviewed in DDH cases.

RESULTS

In a total of 171 patients with DDH, 21 suffered from dislocation after THA (12%) which was significantly more frequent than those with primary OA. In univariate analysis, higher grade of dysplasia, smaller head size, intra-operative fracture, Wagner Cone stem, failure of offset restoration, and implanting the cup outside the Lewinnek's safe zone were identified as predictors of dislocation. In multiple regression analysis, however, only higher Crowe grade, intra-operative fracture, and post-operative acetabular offset less than 16 mm were independent predictors of dislocation.

CONCLUSION

Dysplastic hips can be more prone to post-THA dislocation than those with primary OA. Higher grades of dysplasia, failure of offset restoration, and intra-operative fracture can increase the rate of dislocation in this group of patients.

Is Obesity Associated with Higher Complication Rates in Total Hip Arthroplasty for High-Riding Dysplastic Hips?

OBJECTIVE

Developmental dysplasia of the hip (DDH) is a disabling pathology leading to hip problems, such as painful arthritic hip, unstable hip, etc. Total hip arthroplasty (THA) is an effective treatment modality for this condition. Obesity has been shown to be associated with increased rates of complications following orthopaedic surgeries (Journal of Arthroplasty 20:46-50). The hypothesis of this study was that patients with a body mass index (BMI) greater than 30 (obese), who undergo total hip arthroplasty for dysplastic hip, are associated with longer operative and anaesthetic times, longer hospital stays and higher re-admission rates within 30 days.

METHODS

All the cases of total hip arthroplasty in patients with high-riding dysplastic hips were reviewed. Evaluation was made of a total of 68 patients comprising 64 females and 4 males, classified into two groups. Patients with BMI < 30 kg/m2 formed the non-obese group and patients with BMI ≥ 30 kg/m2 the obese group.

RESULTS

The mean age was 44.67 ± 6.49 years. BMI was < 30 in 44 (64.7%) patients and > 30 in 24 (35.3%) patients. The data analysis showed that mean surgical time, anaesthesia duration and re-admission rate were significantly higher in the group with BMI ≥ 30(obese) as compared to the group with BMI < 30 (non-obese) (p < 0.01). The complication rate was determined to be higher in the obese group (p < 0.05).

CONCLUSION

Obese patients performed with total hip arthroplasty for high-riding dysplastic hips had more complications and higher rates of re-admission to hospital compared with the non-obese patients.

Survival rates and reasons for revision of different stem designs in total hip arthroplasty for developmental dysplasia: a regional registry study

INTRODUCTION

Total hip arthroplasty (THA) in dysplastic hips is challenging, and each specific implant used in this context has been associated with specific complications. A registry study was performed to query survival rates, hazard ratios, and reasons for revision of different stem designs in THAs after developmental dysplasia of the hip.

MATERIALS AND METHODS

A regional arthroplasty registry was inquired about cementless THAs performed for hip dysplasia from 2000 to 2017. Patients were stratified according to stem design in tapered (TAP; wedge and rectangular), anatomic (ANAT), and conical (CON), and divided on the basis of modularity (modular, M; nonmodular, NM). In total, 2039 TAP stems (548 M and 1491 NM), 1435 ANAT (1072 M and 363 NM), and 2287 CON (1020 M and 1267 NM) implants were included. Survival rates and reasons for revisions were compared.

RESULTS

The groups were homogeneous for demographics, but not fully comparable in terms of implant features. NM-CON stems showed the highest risk of failure (significant) and a high risk for cup aseptic loosening (2.5%). The adjusted risk ratio showed that NM-CON was more prone to failure (HR versus NM-ANAT: 3.30; 95%CI 1.64-7.87; p = 0.0003). Revision rates for dislocations and stem aseptic loosening did not differ between cohorts.

CONCLUSIONS

NM-CON stems showed the highest risk of failure, especially high rates of cup aseptic loosening. NM-CON implants were not more prone to dislocations and stem aseptic loosening. Clinical comparative studies are required to investigate the causes of NM-CON failures, which may be due to abnormal acetabular morphology or imperfect restoration of the proximal biomechanics.

Bilateral Total Hip Arthroplasty in the Setting of Developmental Dysplasia of the Hip and Extreme Hip Flexion Requirements due to Phocomelia

Phocomelia is a rare congenital birth defect marked by hypoplastic or markedly absent limbs. Developmental dysplasia of the hip (DDH) is a congenital disorder with a failure of the native acetabulum to provide complete coverage over the femoral head. The secondary osteoarthritis that develops from DDH is technically challenging for orthopedic surgeons because of distorted anatomy. The present case describes the diagnosis of Crowe 3 DDH in a phocomelia patient with hyperflexion requirements who successfully underwent staged bilateral total hip arthroplasty via a direct anterior approach. It highlights the utility of preoperative computerized tomography and intraoperative computer navigation to assist in implant placement. Recognizing difficult arthroplasty cases in advance is imperative as these cases may require great expertise and more extensive surgical planning.

Prior Pelvic Osteotomy Affects the Outcome of Subsequent Total Hip Arthroplasty

BACKGROUND

Although pelvic osteotomy (PO) is an important surgical procedure that can alleviate symptoms and potentially slow progression of osteoarthritis in patients with development dysplasia of the hip, some patients eventually require conversion to total hip arthroplasty (THA). This study aimed to determine the outcome of conversion THA in patients with prior PO.

METHODS

Forty nine patients with a history of prior PO who underwent conversion THA at a single institution were matched at a 1:3 ratio based on the date of surgery, age, gender, and body mass index with 147 developmental dysplasia of the hip patients who underwent primary THA without prior PO. A retrospective chart review was performed to compare outcomes at a minimum follow-up of 2 years.

RESULTS

Patients with prior PO required more supplemental screw fixation for the acetabular component (59.2% vs 38.1%, P = .016), more autologous bone grafting (24.5% vs 11.6%, P = .048), had a longer mean operative time (106.0 vs 79.8 minutes, P < .001), and greater estimated blood loss (350.0 vs 206.8 mL, P = .015). Patients with prior PO had smaller cup version angle (26.0° vs 29.0°, P = .012) and greater discrepancy in the limb length (10.3 vs 7.26 mm, P = .041). Eight hips (16.3%) with prior PO and 6 (4.1%) without osteotomy required reoperation (P = .008). There was no difference in outcome scores at the latest follow-up.

CONCLUSION

THA after prior PO is technically demanding, leading to longer operative times, greater blood loss, and variation in implant placement. Although functional outcomes are similar, THA after a prior PO is more likely to require reoperation.

CONCLUSION

THA after prior PO is technically demanding, leading to longer operative times, greater blood loss, and variation in implant placement. Although functional outcomes are similar, THA after a prior PO is more likely to require reoperation.

The Use of Robotic-Assisted Total Hip Arthroplasty in Developmental Dysplasia of the Hip

BACKGROUND

Total hip arthroplasty (THA) is an effective operation for patients with hip osteoarthritis; however, patients with hip dysplasia present a particular challenge. Our novel study examined the effect of robot-assisted THA in patients with hip dysplasia.

METHODS

We retrospectively reviewed patients with developmental dysplasia of the hip undergoing primary THA using robotic arm assistance at 2 institutions from January 2010 to January 2017. Patients undergoing revision arthroplasty were excluded. Preoperatively, all patients underwent a computed tomography scan so that 3-dimensional templating could be performed. Hip range of motion (ROM) and clinical leg length discrepancy were recorded preoperatively. Two independent observers calculated Crowe and Hartofilakidis grades for each operative hip. At the final follow-up, hip ROM, postoperative complications, and modified Harris Hip scores were obtained.

RESULTS

Seventy-nine patients underwent THA because of degenerative joint disease in the setting of developmental dysplasia of the hip. There were 56 females and 23 males with a mean age of 45 years (range: 26-64 years). We found that components were placed according to the preoperative plan, that there was an improvement in the modified Harris hip score from 29 to 86 (P < .001), an improvement in the hip ROM (flexion improvement from 66° to 91°, P < .0001), and a correction of leg length discrepancy (17.1 vs 4 mm, P < .0002). There were no complications during the short-term interim follow-up (mean: 3.1 years).

CONCLUSIONS

Robot-assisted THA can be a useful method to ensure adequate component positioning and excellent outcomes in patients with hip dysplasia.

LEVEL OF EVIDENCE

Level III, Retrospective.

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.

Mid-term results of short-stem total hip arthroplasty in patients with Crowe type I and II developmental dysplasia of the hip

BACKGROUND

This study aimed to evaluate the clinical and radiographic mid-term results of short-stem THA in patients with DDH.

METHODS

We reviewed 32 cases that underwent Metha stem between November 2010 and February 2015. WOMAC scores, Oxford Hip Scores (OHS) and Harris Hip Scores (HHS) were recorded to evaluate the clinical results. The appearance of bone trabeculae development and stress shielding was analyzed.

RESULTS

The mean age of patients was 50.3 years (33-67) with the mean follow-up of 77 months (60-106). According to Crowe classification, 13 cases were graded as Crowe I and 19 cases as Crowe II. According to Dorr classification, 17 cases were graded as Dorr A and 15 cases as Dorr B. The postoperative WOMAC scores decreased, and OHS and HHS increased significantly compared with preoperative (p < 0.001). The caput-column-diaphysis angles decreased significantly (p < 0.001) and limb length discrepancy decreased significantly (p = 0.013) after surgery. The radiographic change around the stem showed bone trabeculae development at zones 1 (93.9%), 2 (93.9%), 3 (25%), 5 (6.3%), 6 (96.9%) and 7 (90.6%). There was grade 1 stress shielding in 30 cases (93.9%). There was no stem subsidence greater than 2 mm in all hips, no sciatic nerve injury or no dislocation. Neither acetabulum nor femoral stem was defined as definite loosening, and none of the implants was revised.

CONCLUSIONS

The short stem showed promising mid-term clinical results in patients with DDH. The radiographic results demonstrated that the short stem provided physiological proximal load transfer with less stress shielding, being a useful alternative for femoral reconstruction.

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.

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

BACKGROUND

Total hip arthroplasty is a successful treatment for hip osteoarthritis. Primary and secondary implant fixation is dependent on implant design and plays an important role in the longevity of an implant. In this study, we assessed the self-locking cementless Master^SL femoral stem.

MATERIALS AND METHODS

In this single-centre prospective study, 50 consecutive hips with the indication for total hip arthroplasty, who met the inclusion criteria, received the Master^SL stem from LIMA Corporate. Patients had pre- and post-operative clinical and radiological assessment and completed patient-reported outcome measures [Oxford Hip Score (OHS), Harris Hip Score (HHS) and Forgotten Joint Score (FJS)] at the 6-week and 6-, 12- and 24-month mark. Post-operative X-rays were assessed for osteointegration (Engh Score), alignment and subsidence.

RESULTS

After 2 years, aseptic survival was 100%. One hip had to be explanted due to early deep infection and was excluded from the study. At 2 years, the patients reported a significant improved HHS and OHS of 95.3 ± 5.8 and 46.1 ± 3.6 (mean ± standard deviation), respectively, compared to preoperatively. The mean ± standard deviation for the FJS was 86.4 ± 18.7 with two-thirds of the patients reporting a score above 85. The mean Engh score is 15.1 ± 5.9 (mean ± standard deviation) with no patient scoring below 1 which suggests good osteointegration in all femoral stems.

CONCLUSIONS

The Master^SL femoral stem performed well in this short-term follow-up study, with high patient satisfaction and good signs of osteointegration. Long-term follow-up will be necessary to evaluate longevity.

LEVEL OF EVIDENCE

Level 3, Prospective cohort study.

TRIAL REGISTRATION

The study was registered on the 30.03.2016 with Australia New Zealand Clinical Trials Registry (ACTRN12617000550303).

[Challenges of primary hip arthroplasty with high hip dislocation]

BACKGROUND

Endoprosthetic care of high hip dislocation is a surgical challenge. The hip anatomy is greatly altered in these patients, including a rather flat and small acetabulum with impaired bone quality and a relevant chance of a bony defect of the acetabular roof. Additionally, the front coverage and in some cases even the dorsal coverage of the hip are missing. The proximal femur is characterized with an increased antetorsion, a coxa valga position and an enlarged greater trochanter. The medullary cavity is narrowed, the offset is reduced, and the absolut leg length can be enlarged. Further anatomic variations can have been caused by previous surgeries.

AIM OF THE TREATMENT

The goal of the endoprosthetic care is the re-creation of a hip with an anatomic center of rotation, an anatomic offset and equal leg length.

TREATMENT

This can be achieved by a medial shift of the acetabular cup. An acetabular osteotomy including central cancellous bone graft or a bony graft to reinforce the acetabular roof might be necessary. In cases in which an anatomic acetabular cup placement is not possible, a more cranial placement can be done. Further strategies that are essential in several cases are shortening or re-orientation osteotomies of the femur, reaming of the medullary cavity and correct implant selection. Additionally, thorough soft tissue management is of main importance. Generally, the surgery should be well prepared preoperatively.

Dual offset metaphyseal-filling stems in primary total hip arthroplasty in dysplastic hips after a minimum follow-up of ten years

PURPOSE

The aim of this study was to assess the long-term performance of tapered one-third proximally coated stems in dysplastic hips.

METHODS

This study included 135 dysplasia patients (150 hips) who underwent a total hip arthroplasty and had a minimum follow-up of ten years. Single design tapered stems were used in all patients. There were 112 women (83%) and 23 men (17%) with a mean age of 45 years (23 to 72) at the time of surgery. The mean follow-up was 14.7 years (10 to 16.8). For clinical evaluation, the Harris Hip Score and Merle D'Aubigne scale were used pre-operatively and at the final follow-up. Implant survival was calculated using Kaplan-Meier survivorship analysis, with failure defined as a component revision for any reason.

RESULTS

Overall, one stem was revised for a deep infection. There were no other femoral stem revisions secondary to loosening, wear, periprosthetic fracture, or instability. Radiographic evaluation showed excellent stem osteointegration in all cases. Kaplan-Meier survivorship, with stem revision for any reason as the end point, was 98% at 14 years (95% confidence interval 92.5 to 99.8).

CONCLUSION

This study demonstrates that a dual offset tapered stem achieved excellent survivorship and stability, as well as good clinical outcome scores with minimal thigh pain and stress shielding in patients with arthritis and developmental dysplasia of the hip; a dual offset tapered stem may be a suitable option for primary total hip arthroplasty in this group.

Implant Survival and Patient-Reported Outcomes After Total Hip Arthroplasty in Young Patients

BACKGROUND

Younger patients are undergoing total hip arthroplasty (THA) for various conditions that affect the hip joint. This study evaluates the implant survival and long-term patient-reported outcomes of THA in patients aged 35 years or younger.

METHODS

Data were collected through a retrospective chart review, and follow-up surveys were conducted to determine implant survival and patient-reported outcomes. Kaplan-Meier survival analysis was performed to evaluate implant survival, and the hip disability and osteoarthritis outcome score (HOOS) was used to describe patient-reported outcomes. Descriptive statistics were used to summarize baseline and follow-up data, and univariate and multivariate analyses were used to compare implant survival and patient-reported outcomes.

RESULTS

This study included 400 patients (548 THAs). The average age at the time of surgery was 27 (range: 8-35) years, and the mean time to follow-up was 14 (range: 2-29.7) years. The 10- and 20-year implant survival was 87% and 61%, respectively. Implant survival differed based on primary diagnosis (P = .05), and it was significantly better in patients aged 25 years or older at the time of surgery, male patients, and patients with ceramic-on-ceramic or ceramic-on-plastic implants (P < .05). Mean HOOS scores at follow-up were 86 for pain, 84 for symptoms, 86 for ADLs, and 77 for sports. All HOOS scores were significantly worse after revision THA (P < .01).

CONCLUSION

Young patients have good implant survival and favorable long-term outcomes after THA. There are several predictors of implant survival and patient-reported outcomes after THA in young patients.

Is a short stem suitable for patients with hip dysplasia? A report on technical problems encountered during femoral reconstruction

INTRODUCTION

A wide variety of stems have been used for the treatment of osteoarthritis secondary to advanced hip dysplasia. Since evidence for using short stems in dysplastic hips is limited, we planned to analyse the technical problems encountered when reconstructing the proximal femur of patients with osteoarthritis secondary to congenital dysplasia of the hip treated with total hip arthroplasty (THA) using a type 2B short stem.

METHODS

We prospectively analysed 17 patients (22 hips) treated with primary THA performed with a single-branded short uncemented stem with metaphyseal fixation (MiniHip™; Corin). We excluded cases in which other type of stems were used, or in which retrospective data was only available. Mean follow-up was 41.22 months (minimum 24). We analysed clinical outcome using the modified Harris Hip Score (mHHS) and pain using the visual analogue scale (VAS). Radiographs were examined in order to determine causes of complications and revision surgery.

RESULTS

All patients showed statistically significant improvement when preoperative and postoperative values for mHHS (54.19 vs. 94.57; p = 0.0001) and for pain VAS (8.71 vs. 0.71; p = 0.0003) were compared. No cases of thigh pain, instability or infection were found. 1 case of acetabular cup loosening and 1 case of periprosthetic fracture were diagnosed at 8 months and 45 days, respectively. Overall survival was 84.7% at 5 years (CI 95%, 64.4-105.3) with revision for any reason as an end point. When stem performance was separately evaluated, it showed a survival rate of 100% at 5 years with revision for aseptic loosening as an end point.

CONCLUSIONS

THA with a type 2B short stem for the treatment of dysplastic osteoarthritis showed very few technical intraoperative problems, being a useful alternative for femoral reconstruction.

High-Riding Congenital Hip Dislocation: THA With Unilateral vs Bilateral Transverse Femoral Shortening Osteotomy

BACKGROUND

We argue that 1-stage bilaterally total hip arthroplasty (THA) could be acceptable in bilateral coxarthrosis because of high-riding developmental dysplasia of the hip (DDH).

METHODS

Sixty-nine cases (51 patients) of high-riding DDH in patients who underwent THA from 2010 to 2013 were reviewed. Patients were divided into 2 groups: unilateral (group 1) and 1-stage bilateral surgery (group 2). The clinical measurements were the visual analog scale and Harris Hip Score.

RESULTS

The average follow-up was 37.3 months for group 1 and 38.8 months for group 2. The hospital stay time was 5.2 days in group 1 and 6.2 days in group 2 (P = .334). The mean Harris Hip Score and visual analog scale score were improved significantly after surgery for both groups, and there was no statistically significant difference (P = .988). There was no difference between groups 1 and 2 in terms of complications (P = .137).

CONCLUSION

Our data confirm that 1-stage bilateral transverse osteotomy with THA is an effective method as unilateral and it does not increase the length of patients' hospital stays and features a low risk of postoperative complications in the treatment of patients with high-riding DDH.

High congenital hip dislocation in adults - arthroplasty and functional results

Objective

Retrospective case–control study on the authors’ experience regarding arthroplasty in high congenital dislocations of the hip in adults.

Methods

Sample with 11 high congenital hip dislocations (Hartofilakidis type C) that occurred in seven patients, who were submitted to hip arthroplasty by the same surgeon and with the same surgical technique. Mean follow-up period was 4.32 ± 2.67 years (minimum one year) and all patients were evaluated by the same examiner.

Results

All the arthroplasties had cementless fixation, with application of screwed acetabular cups, conical femoral stems, and a metal-polyethylene articular pars. In every patient, shortening femoral osteotomies were performed at subtrochanteric or supracondylar locations. The mean Harris Hip Score at the last evaluation was 88.55 ± 4.50 (range 81–94). The mean time with high dislocation of the hip (42.91 ± 14.59 years, range 19–68) showed a significant inverse correlation with Harris Hip Score (r = 0.80; p = 0.003). All patients reported important relief of pain complaints and are capable of ambulation without any external support. In the unilateral dislocations, leg length discrepancies were fully corrected; in the bilateral cases, isometric limbs were achieved in all patients. All osteotomies consolidated, with a mean interval of 3.27 ± 0.47 months. There were complications in 18.18% of the sample: one iatrogenic intraoperative fracture of the greater trochanter and a transitory sciatic neurapraxia.

Conclusion

Despite being a demanding surgery with a reportedly high complication rate, total hip arthroplasty in high congenital dislocations, when properly indicated and technically correctly performed, allows an improvement in function and quality of life.

Midterm Outcome of Cementless Total Hip Arthroplasty in Crowe IV-Hartofilakidis Type III Developmental Dysplasia of the Hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is widespread in developing countries, and treating Crowe IV-Hartofilakidis Type III DDH in adults requires the use of a highly demanding technique.

METHODS

We sought to determine the outcome of cementless total hip arthroplasty using Zweymüller components to treat Crowe IV-Hartofilakidis Type III DDH. Fifty-eight patients (71 hips) with a mean age of 35.8 years at time of index operation were included in our study. The average duration of follow-up was 70.5 months. The acetabular component was placed in the true acetabulum in all cases, and subtrochanteric shortening osteotomy was performed in 61 hips.

RESULTS

With any component revision for any reason as the end point, Kaplan-Meier survivorship analysis at 98 months revealed a cumulative survival rate for implanted components of 91.40%. The mean Harris Hip Score improved from 35.6 preoperatively to 82.9 postoperatively. There were 20 cases of intraoperative fracture, 1 case of complete nerve palsy, and 7 cases of transient nerve palsy. Revision surgery was performed in 7 patients because of cup loosening in 1, severe polyethylene wear in 4, cup breakage in 1, and dislocation in 1.

CONCLUSIONS

Midterm results for cementless total hip arthroplasty in patients with Crowe IV-Hartofilakidis Type III DDH was satisfactory; however, intraoperative fracture and polyethylene wear were major complications.

MODULUS Stem for Developmental Hip Dysplasia: Long-term Follow-up

Between October 2001 and December 2010, 143 patients with developmental dysplasia underwent hip arthroplasty surgery using a conical stem with modular necks (MODULUS system, Lima Corporate, Villanova di San Daniele del Friuli, Italy). Thirty (21.0%) patients had both hips replaced, for a total of 173 implants. The mean age at the time of surgery was 55 years (range: 22-81 years). The mean follow-up was 87 months (range: 36-146 months); average Harris Hip Score increased from 42 (range: 23-65) preoperatively to 92 (range: 76-100) at the last follow-up. Stem revision was required in two cases. The MODULUS stem showed good long-term clinical and radiographic results, with a Kaplan-Meier survivorship of 97.6% (95% CI: 94.8-100.0%) at 8 years.

Oblique femoral shortening osteotomy in total hip arthroplasty for high dislocation in patients with hip dysplasia

PURPOSE

The aim of this study was to evaluate outcomes after implantation of total hip arthroplasty for developmental dysplasia with high dislocation of the hip using conical stems combined with oblique subtrochanteric shortening osteotomy.

METHODS

We retrospectively reviewed the functional scores, radiographic results, and complications in a consecutive series of 16 hips (12 patients) with Crowe IV developmental dysplasia of the hip. The average age at surgery was 53.2 years and the patients were operated on between 1999 and 2008.

RESULTS

The average Harris Hip Score improved from 37.2 to 83.7 at a mean follow-up of 8.7 years. All acetabular cups were inserted into the true acetabulum and all prosthetic components were stable at the last follow-up visit. No neurovascular damage was recorded. Complications arose in six hips (37.5%): intra-operative fracture of proximal femur requiring fixation (n = 2); dislocation (n = 3); and asymptomatic non-union of the osteotomy (n = 1). The osteotomy healed within less than six months in all the remaining cases.

CONCLUSIONS

With the numbers given the oblique femur shortening osteotomy led to an increased rotational stability and proved to be a simple and effective method. Compared with transverse osteotomy and as related to our experience, this technique may be a method of choice in selected cases.

Total hip arthroplasty with a non-modular conical stem and transverse subtrochanteric osteotomy in treatment of high dislocated hips

Conventional stems may be unsuitable for hypoplastic femurs associated with severe dysplasia, meanwhile, custom-made or modular stems in total hip arthroplasty are often complex and expensive. This series included 21 Crowe type IV dysplastic hips in which a non-modular cementless conical stem was implanted with transverse subtrochanteric femoral osteotomy. Follow up averaged 40months. Twenty hips survived with mean Harris hip score improved from 52 to 90. One hip failed for stem loosening. The average leg lengthening was 3.8cm with transient sciatic nerve palsy occurring in three hips. Femoral offset averaged 3.3cm postoperatively. The non-modular conical stem not only obviated the complexities, high medical cost and potential risk at the neck-stem interface associated with stem modularity, but also simplified surgical technique.

Is cup positioning challenged in hips previously treated with periacetabular osteotomy?

After periacetabular osteotomy (PAO), some patients develop osteoarthritis with need of a total hip arthroplasty (THA). We evaluated the outcome of THA following PAO and explored factors associated with inferior cup position and increased polyethylene wear. Follow-up were performed 4 to 10 years after THA in 34 patients (38 hips) with previous PAO. Computer analysis evaluated cup position and wear rates. No patient had dislocations or revision surgery. Median scores were: Harris hip 96, Oxford hip 38 and WOMAC 78. Mean cup anteversion and abduction angles were 22° (range 7°-43°) and 45° (range 28°-65°). Outliers of cup abduction were associated with persisting dysplasia (CE <25°). THA after PAO can produce excellent clinical results. Persisting acetabular dysplasia following PAO may lead surgeons to place the acetabular component in excessive cup abduction, and this tendency should be recognized at the time of the PAO.

Influence of surgical experience in the learning curve of a new approach in hip replacement: anterior mini-invasive vs. standard lateral

There is conflicting evidence regarding the potential benefit of minimally invasive surgery for total hip arthroplasty (THA), especially during the 'learning curve' of individual surgeons. Sixty patients who underwent THA between January and December 2010 were evaluated. The aim was to assess the anterior mini-invasive (MI) approach performed in 30 patients during the learning curve of a single experienced hip surgeon compared with the results of 30 patients operated upon through a standard lateral approach by the same surgeon. Operation and hospitalisation times, blood loss, number of transfusions, peri-operative complications and femoral/acetabular component placement were monitored. Harris Hip Score (HHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS) were analysed before and 12 months after surgery. Pain Visual Analogue Scale (VAS) was also recorded 1 week and 1 month after surgery. Hospitalisation, blood loss, number of transfusions and VAS score 1 week postoperatively were significantly lower and operative time was significantly longer in the anterior MI approach. Similar functional outcomes 1 year after surgery, component positioning and complication rates were observed in both groups. The results suggest that anterior MI approach is a safe procedure during the learning curve of an experienced hip surgeon.

Greater trochanter osteotomy with cementless THA for Crowe type IV DDH

This study explored the surgical method and short-term clinical effect of a greater trochanter osteotomy along with cementless artificial total hip arthroplasty in the treatment of Crowe type IV developmental dysplasia of the hip. The authors conducted a retrospective analysis of 18 patients (22 hips) with Crowe type IV dysplasia who were seen between June 2008 and August 2010. After undergoing cementless artificial total hip arthroplasty using a posterolateral approach, a greater trochanter osteotomy was used to adjust the tension of the gluteal muscle, and an acetabular cup was placed. Average preoperative length shortening of the affected limb was 4.5 cm (range, 3.4-6 cm), and average postoperative length increase was 4.0 cm (range, 3.2-4.8 cm). Average postoperative Harris Hip Score was 87 (range, 79-91), which was higher than the average preoperative score of 38 (range, 32-51). Intraoperatively, 3 hips (3 patients) sustained a proximal femur fracture. Due to the stability of the femoral prosthesis, either no treatment or wire fixation only was given; by 2 months postoperatively, radiographs indicated that all fractures had healed. One patient had symptoms of sciatic nerve paralysis that resolved 3 months postoperatively. Performing a greater trochanter osteotomy after cementless artificial total hip arthroplasty is effective for the treatment of Crowe type IV dysplasia and can rebuild the complex biology and biomechanics of hip dysplasia without increasing the complication risk.

Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up

BACKGROUND

Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up.

MATERIALS AND METHODS

Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10-14 years).

RESULTS

Average Harris Hip Score was 56 ± 9 (range 45-69) preoperatively, 90 ± 9 (range 81-100) 12 months after surgery, and 91 ± 8 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised.

CONCLUSIONS

Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results.