Short stem survival after osteonecrosis of the femoral head

[Short hip stem for THA in avascular necrosis of the femoral head]

INTRODUCTION

Osteonecrosis of the femoral head or avascular necrosis of the femoral head (HKN) is a complex disease that, without treatment, leads to infraction of the femoral head in most cases. In these cases, only replacement of the hip joint will help, although there is no clear recommendation of an arthroplasty type. In the last two decades, the treatment of primary and secondary coxarthrosis with short-shaft prostheses with different anchoring philosophies has increased. Since short-shaft fitting is a possible option especially in younger patients, the question arises about possible fittings of advanced HKN with these stem types, especially with metaphyseal anchorage. The aim of this study was to review the existing literature on the results of short stem prosthesis in HKN and to present the advantages and disadvantages of short stem prosthesis in osteonecrosis of the femoral head.

MATERIAL AND METHODS

This review analyzes the existing studies on short stem arthroplasty for HKN.

RESULTS

Only a few studies exist that have analyzed clinical and radiologic outcomes of short stem replacement in HKN.

CONCLUSION

The existing short- and medium-term results show mostly good outcomes. However, it is difficult to draw a general conclusion due to differences in stem design and fixation. Short stems with primary diaphyseal fixation do not show an increased risk of failed osseointegration or loosening. Constructions with primary metaphyseal fixation should undergo MRI to rule out the possibility of necrosis extending beyond the femoral neck.

Total hip arthroplasty with ultra-short uncemented stem in patients with osteonecrosis of the femoral head: mid-term results

BACKGROUND

Mid-term results (clinical and radiographic) of ultra-short anatomical cementless stem total hip arthroplasty (THA) in patients with osteonecrosis of the femoral head (ONFH) has not often been presented. The aim of this study is to evaluate THA using the Proxima stem in patients with ONFH in the mid-term.

METHODS

The study consists of 73 patients (97 THAs) with a Proxima stem implanted between 2006 and 2015. The mean age of patients was 47.4 years, with a mean follow-up 105.2 months. The clinical results include preoperative and postoperative Harris Hip Scores (HHSs). Radiological follow-up reports on stem migration, bony trabecular development and radiolucent lines. The complications and revisions were registered. Kaplan-Meier survival analysis was performed to determine the implant survival.

RESULTS

The average HHS improved significantly from 40.3 preoperatively to 98.0 at the final evaluation (p ˂ 0.0001). Stem migration (subsidence and "varisation") was observed in 11 hips (in 9 of them up to 6th postoperative month without any further progression, in 2 with progressive migration and radiological loosening). Bony trabecular development was detected in modified Gruen zones (1,2,4,6,7 for Proxima stem): in zone 1 (0%), 2 (67.0%), 4 (64.9%), 6 (64.9%), 7 (0%). Radiolucent lines were observed in 1 cup and 6 stems (2 were loose, 4 with fibrous stable fixation). Complications were found in 5 hips (5.1%): squeezing hip once, repeated dislocation in 1, 1 early deep infection, and 2 loose stems. 2 hips (2.1%) were revised (dislocation, infection). The implant survival was 98.9% and 97.9% clinically and radiologically, respectively.

CONCLUSIONS

Observations in the mid-term show that the clinical and radiological results of the Proxima stem in patients with ONFH are promising. The stem design preserves the proximal femoral bone stock. The bony trabecular appearance confirms physiological proximal femoral load transmission.

Calcar-guided short-stem total hip arthroplasty: Will it be the future standard? Review and perspectives

Short stems in total hip arthroplasty (THA) are becoming increasingly popular. In Germany, already 10.4% of all primary THAs are performed using a cementless short stem. The concept of modern, calcar-guided, short stems aims for an individualized reconstruction of the hip anatomy by following the calcar of the femoral neck, a bone- and soft-tissue-sparing implantation technique, and physiological loading. The stem design uses either metaphyseal fixation alone or additional diaphyseal anchoring, depending on the stem alignment and indication. These individualized anchorage types increase the potential indications for the safe use of a short stem. The design features may account for potential advantages of current short stem implants compared with earlier short-stem designs, particularly in cases of reduced bone quality or osteonecrosis of the femoral head and femoral neck fractures. The implantation technique, however, requires distinct knowledge regarding the characteristics of varus and valgus positioning, with the potential for clinical consequences. A learning curve for surgeons new to this technique must be taken into account. Cortical contact with the distal lateral cortex appears to be crucial to provide sufficient primary stability, and the use of intraoperative imaging to identify “undersizing” is highly recommended. Current results of several national registries indicate that calcar-guided short stems are among the most successful implants in terms of mid-term survivorship. However, long-term data remain scarce. This review introduces the characteristics of calcar-guided short-stem THA and summarizes the current evidence.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today?: A 5-Year Update

➢. Clinicians should exercise a high level of suspicion in at-risk patients (those who use corticosteroids, consume excessive alcohol, have sickle cell disease, etc.) in order to diagnose osteonecrosis of the femoral head in its earliest stage. ➢. Nonoperative treatment modalities have generally been ineffective at halting progression. Thus, nonoperative treatment is not appropriate in early stages when one is attempting to preserve the native joint, except potentially on rare occasions for small-sized, medially located lesions, which may heal without surgery. ➢. Joint-preserving procedures should be attempted in early-stage lesions to save the femoral head. ➢. Cell-based augmentation of joint-preserving procedures continues to show promising results, and thus should be considered as an ancillary treatment method that may improve clinical outcomes. ➢. The outcomes of total hip arthroplasty in the setting of osteonecrosis are excellent, with results similar to those in patients who have an underlying diagnosis of osteoarthritis.

Outcome of short- to medium-term migration analysis of a cementless short stem total hip arthroplasty using EBRA-FCA: a radiological and clinical study

INTRODUCTION

Stress shielding may lead to aseptic loosening which is a common reason for implant failure. An established method to identify implants with risk of implant failure caused by aseptic loosening is to measure early migration of the stem with the "Ein Bild Roentgen Analyse" femoral component analysis (EBRA-FCA). Therefore, the aim of this study was to measure the migration of a cementless short stem prosthesis via EBRA-FCA to predict the future performance.

MATERIALS AND METHODS

A total collective of 71 patients were treated with a cementless short hip stem prosthesis. Indications for surgery were primary coxarthrosis, dysplasia coxarthrosis or femoral head necrosis. After surgery, the patients were followed-up immediately after 3, 6, 12, 24, 36, and 48 months and X-ray images for EBRA-FCA measurements were taken. Axial caudal migration as well as the varus/valgus tilting of the prosthesis was determined. Possible influencing factors like BMI, age, diagnosis, gender or Harris Hip Score (HHS) on the migration of the stem were assessed.

RESULTS

HHS increased significantly direct postoperatively (p < 0.001). At the second follow-up the average caudal migration was 0.42 ± 0.52 mm (range: 0.00-2.85 mm) (p < 0.001). A total of 14 patients underwent a caudal migration greater than 1.5 mm until 48 months. The initial varus and valgus tilts within the first 3 months were significant (p < 0.001). No correlations between BMI, age, diagnosis, gender or HHS and the migration as well as the tilting of the cementless short hip stem prosthesis were found.

CONCLUSIONS

Although initial axial caudal migration as well as tilting tendencies in varus or valgus position can be detected, there is no marked migration of the examined prosthesis after the first 48 months. Likewise, no aseptic early loosening was detected throughout the study period, which indicates good osseointegration of the short stem prosthesis.

Primary stability of calcar-guided short-stem total hip arthroplasty in the treatment of osteonecrosis of the femoral head: migration analysis using EBRA-FCA

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) is a disabling condition that often results in secondary arthritis necessitating total hip arthroplasty (THA). Short-stem THA has constantly gained popularity. It remains controversial, whether ONFH represents a risk factor for failure after the implantation of short stems with pronounced metaphyseal anchorage. The potential spread of the osteonecrotic area and bone marrow edema into the metaphyseal bone might result in compromised stability. Early implant migration is considered predictive of subsequent aseptic loosening. The purpose of this study was a migration analysis of a modern, calcar-guided short-stem implant in patients with ONFH in a mid-term follow-up.

MATERIALS AND METHODS

This retrospective analysis investigated the migration pattern of 45 calcar-guided short stems in patients with ONFH, using Einzel-Bild-Roentgen-Analyse Femoral-Component-Analysis (EBRA-FCA). Influencing factors such as ARCO categories, age, gender, body weight and BMI were analyzed. Complications and adverse events were documented.

RESULTS

At mid-term [48.1 months (SD 20.7 months)], mean axial migration was 1.56 mm (SD 1.77 mm). Mean migration rate stabilized after 2 years. No influence of ARCO categories, age and BMI was found. A tendency of increased axial migration was observed in male patients and in overweight patients. No revision surgeries had to be performed during follow-up.

CONCLUSION

The results indicate a migration pattern comparable to that of primary osteoarthritis patients with slight initial migration under full load followed by subsequent stabilization in the metaphyseal femur. The 100% survival rate at mid-term supports the usage of this short-stem design in patients with ONFH.

Comparison of short-stem with conventional-stem prostheses in total hip arthroplasty: an 8-year follow-up study

PURPOSE

Coxarthrosis is a common disease of the adult hip joint. Elderly patients have mainly been treated with total hip arthroplasty (THA); however, younger patients are increasingly affected. Short-stem prostheses were developed for this special patient group. There have been few studies on the clinical outcomes of this type of prosthesis. This study compared the mid-term results of a short-stem prosthesis and a standard-stem prosthesis 8 years after implantation.

METHODS

According to our clinical registry, patients who received a short-stem prosthesis before 2011 were identified. Patients in the standard-stem prosthesis group were matched based on the sex, age, height, weight, and degree of arthrosis. At the follow-up time, the modified Harris Hip Score (mHHS), University of California Los Angeles (UCLA) activity score and visual analog scale (VAS) pain score were collected and compared with the preoperative values.

RESULTS

Fifty-five patients could be matched and analyzed for both groups. No patients needed revision surgery. In both groups, there were significant improvements at the follow-up time. The pre- and postoperative mHHSs, UCLA scores, and VAS scores were 41.9 and 95 (p < 0.0001), 3.75 and 7.9 (p < 0.0001), and 7.6 and 0.9 (p < 0.0001), respectively, in the short-stem group and 44.8 and 96.25 (p < 0.0001), 3.6 and 7.7 (p < 0.0001), and 7.7 and 0.9 (p < 0.0001), respectively, in the control group, with no significant differences between the groups at the follow-up time.

CONCLUSION

The short-stem prosthesis provides mid-term results comparable to those of a standard-stem prosthesis. In both groups, excellent patient-reported outcomes were achieved after an average of 8 years.

LEVEL OF EVIDENCE

IV.

Short stems have lower load at failure than double-wedged stems in a cadaveric cementless fracture model

Objectives

Periprosthetic femoral fractures (PFFs) have a higher incidence with cementless stems. The highest incidence among various cementless stem types was observed with double-wedged stems. Short stems have been introduced as a bone-preserving alternative with a higher incidence of PFF in some studies. The purpose of this study was a direct load-to-failure comparison of a double-wedged cementless stem and a short cementless stem in a cadaveric fracture model.

Methods

Eight hips from four human cadaveric specimens (age mean 76 years (60 to 89)) and eight fourth-generation composite femurs were used. None of the cadaveric specimens had compromised quality (mean T value 0.4 (-1.0 to 5.7)). Each specimen from a pair randomly received either a double-wedged stem or a short stem. A materials testing machine was used for lateral load-to-failure test of up to a maximal load of 5000 N.

Results

Mean load at failure of the double-wedged stem was 2540 N (1845 to 2995) and 1867 N (1135 to 2345) for the short stem (p < 0.001). All specimens showed the same fracture pattern, consistent with a Vancouver B2 fracture. The double-wedged stem was able to sustain a higher load than its short-stemmed counterpart in all cases. Failure force was not correlated to the bone mineral density (p = 0.718).

Conclusion

Short stems have a significantly lower primary load at failure compared with double-wedged stems in both cadaveric and composite specimens. Surgeons should consider this biomechanical property when deciding on the use of short femoral stem.

Cite this article: A. Klasan, M. Bäumlein, P. Dworschak, C. Bliemel, T. Neri, M. D. Schofer, T. J. Heyse. Short stems have lower load at failure than double-wedged stems in a cadaveric cementless fracture model. Bone Joint Res 2019;8:489–494. DOI: 10.1302/2046-3758.810.BJR-2019-0051.R1.

[Total hip replacement in avascular femoral head necrosis]

BACKGROUND

Avascular necrosis of the femoral head is a progressive perfusion disorder of the hip joint. Progress in avascular necrosis causes structural damage to the affected joint, often requiring total hip replacement.

AIM

This article is intended to give the reader an overview of the current literature on total hip replacement of patients with an avascular necrosis of the femoral head.

RESULTS

Before 1990, patients with avascular necrosis of the femoral head had significantly higher revision rates after total hip replacement. Recent studies, however, showed no significant differences in clinical outcomes after total hip replacement in femoral head necrosis and primary osteoarthritis. Despite the young age of the patients, good long-term clinical results can be expected even in patients with an avascular necrosis of the femoral head after total hip replacement.

[Update of the German S3 guideline on atraumatic femoral head necrosis in adults]

The update of the German S3 guideline on atraumatic femoral head necrosis in adults aims to provide an overview of diagnosis and treatment. All clinical studies, systematic reviews, and meta-analyses published in German or English between 01.05.2013 and 30.04.2017 were included. Of 427 studies, 28 were suitable for analysis. Risk factors are corticosteroids, chemotherapy, kidney transplants, hemoglobinopathies, and alcoholism. Differential diagnoses are for example bone marrow edema, insufficiency fracture, and destructive arthropathy. Radiography should be performed upon clinical suspicion. In patients with normal radiography findings but persistent complaints, magnetic resonance imaging (ARCO classification) is the method of choice. Computed tomography (CT) can be used to confirm/exclude articular surface collapse. A subchondral sclerosis zone >30% in CT indicates a better prognosis. Left untreated, a subchondral fracture will develop within 2 years. The risk of disease development in the opposite side is high during the first 2 years, but unlikely thereafter. In conservative therapy, iloprost and alendronate can be used in a curative approach, the latter for small, primarily medial necrosis. Conservative therapy alone as well as other drug-based and physical approaches are not suitable for treatment. No particular joint-preserving surgery can currently be recommended. Core decompression should be performed in early stages with <30% necrosis. From ARCO stage IIIc or in stage IV, the indication for total hip arthroplasty should be checked. Results after total hip arthroplasty are comparable with those after coxarthrosis, although the revision rate is higher due to the relatively young age of patients. Statements on the effectiveness of cell-based therapies such as expanded stem cells or bone marrow aspirates cannot currently be made.

Age-related osseointegration of a short hip stem: a clinical and radiological 24 months follow-up

PURPOSE

The purpose of this study was to examine potential differences between patients under and over 60 years who underwent a total short hip stem arthroplasty in a 24-month follow-up in a clinical setting.

METHODS

Sixty seven patients were included in this prospective study and divided in two groups. In the younger cohort 39 patients ≤ 59 years and in the older cohort 28 patients ≥ 60 years were included. Clinical and radiological examinations of the patients took place preoperatively, postoperatively and after 3, 6, 12 and 24 months. The Harris Hip Score (HHS) was raised as clinical examination. Changes of bone mass density (BMD), stress shielding, reactive lines, spot welds and sclerosing were examined as radiological analysis.

RESULTS

The HHS improved from 53.6 ± 8.2 preoperative to 93.2 ± 9.6 in the younger cohort and for the older cohort from 57.6 ± 14.8 to 94.1 ± 7.6 after 24 months. BMD growth was detectable in regions of interest (ROI) 3 and 6 for both groups. Different results between the cohorts could only be detected in ROIs 4 and 5. The older cohort showed a loss of BMD of 5.95% in ROI 4 and 3.17% in ROI 5 after 24 months, whereas the younger cohort showed no loss of BMD in both ROIs.

CONCLUSIONS

No significant differences or any influences of osseointegration and clinical outcome of the short hip stem for both groups were detectable. Lower losses (ROIs 1 and 2) and higher growths (ROIs 3, 4, 5) were discovered in younger patients and the HHS improved in both groups. Reasons for this result could be age, sex or the level of activity of the patients, but in both groups the short hip stem shows comparable results in clinical as well as in radiological examination. We conclude that the short hip stem seems to be an adequate treatment also for older patients.