The clinical outcome of the Metha short hip stem: a systematic scoping review

Analysis of Postoperative Complication and Revision Rates and Mid- to Long-Term Implant Survival in Primary Short-Stem Total Hip Arthroplasty

Background/Objectives: Short-stem prostheses were introduced as an alternative to conventional straight-stem prostheses. Despite their benefits, including minimally invasive approaches, soft-tissue- and bone-sparing implantation, and physiological load transfer to the metaphysis, data on postoperative complication and revision rates as well as on implant survival are scarce. Methods: A retrospective analysis of 1327 patients who underwent primary total hip arthroplasty (THA) using the Metha® short stem between 2006 and 2023 was conducted. Complication and revision rates were analysed for the intraoperative, direct postoperative, and follow-up episodes. Implant survival was analysed with the endpoint of all-cause stem revision. Results: Intraoperative complications were observed in 3.77% of the cases and included 44 hairline cracks and 6 fractures. In 15 cases (30.0%), conversion to a straight-stem or revision implant was necessary. The direct postoperative complication rate was 2.44%, and 11 revision procedures were performed during inpatient stay (0.84%). Mean follow-up was 7 years (range 1-17). During follow-up, femoral component revision was performed in 60 cases. Aseptic loosening and stem subsidence accounted for a combined percentage of 80% of all indications. Implant survival rate was 95.66% after 5 years, 95.58% after 10 years, and 95.50% after 15 years. Conclusions: Our study provides a comprehensive analysis of postoperative complication and revision rates in a large sample undergoing primary short-stem THA. Postoperative complication rates were favourable, and the long-term implant survival rates were comparable to conventional straight-stem prostheses. Therefore, short-stem THA may be considered an alternative for younger patients.

United States Experience With a Femoral Neck Retaining Total Hip Arthroplasty Stem: A Retrospective Study With Control Comparison From the Literature

BACKGROUND

Femoral neck retaining prostheses have gained popularity in Europe, but the United States has not seen the same trends occurring. Previous reports demonstrate high survivorship for these implants, but to our knowledge, there are no reports examining US data.

METHODS

After institutional review board approval, 824 primary total hip arthroplasties utilizing a femoral neck-retaining prosthesis were examined for femoral component survivorship rates. European studies were systematically reviewed to determine survivorship rates. The data were used to formulate a Kaplan-Meier survivorship curve and compare US data to that of the European studies.

RESULTS

European studies demonstrated survivorship rates for all causes of 97.7 and 99.0% for aseptic loosening at an average of 6 years (range, 4.5 to 10). The current study demonstrated an all-cause 94% Kaplan-Meier survivorship estimate at 5 years and when aseptic loosening only was considered, survivorship increased to 99.4% at 5 years and 98.4% at 11 years.

CONCLUSION

This femoral neck-retaining prosthesis demonstrated excellent survivorship that is comparable to the rates seen in European studies as well as the rates of standard and mid-stem prostheses in the United States.

Ten-year follow-up and clinical outcome of a metaphyseal anchoring short hip stem prosthesis: a retrospective single-centre analysis

PURPOSE

Short stems for total hip arthroplasty are an alternative to traditional conventional long stems. Short stems are designed to facilitate minimal-invasive surgery, improve bone-stock preservation, and mimic a physiological load distribution. However, there is little evidence of the long-term outcome of short stems. This study aims to analyze the ten year survival rates and clinical outcome of one specific metaphyseal short hip stem implant.

METHODS

We retrospectively analyzed the patient records of the patients who underwent a total hip arthroplasty with a monoblock partial collum sparing metaphyseal short hip stem prosthesis in 2008 and 2009 in our clinic. Patients were contacted, and clinical follow-up was recorded using the German version of the modified Harris Hip Score. Furthermore, complications, revision surgery, and post-operative radiographs were analyzed.

RESULTS

Data from 339 primary implantations in 322 patients were retrieved. The mean follow-up was 10.6 years. Seven patients underwent a revision. The ten year survival rate with any revision surgery as the endpoint was 97.5%. The mean modified Harris Hip Score was 86 points (range 30 to 91 points). Five patients had an intraoperative fracture of the femur (1.6%). Two patients (0.6%) had a dislocation of the hip. The stem tip-to-cortex distance, measured in the anterior posterior view, was 2.6 mm (range 0 to 8.3 mm).

CONCLUSION

The ten year survival rate of our used monoblock partial collum sparing metaphyseal short hip stem implant is comparable to traditional stems for total hip arthroplasty.

Comparative Study for Postoperative Initial Fixation Patterns of Two Different Types of Cementless Short Stem Using Three-Dimensional Templating Software

Background

While cementless short stems have become popular in total hip arthroplasty (THA), Metha is a relatively recent development that differs from other short stems in its initial fixation concept of partial collum-sparing metaphyseal anchorage. The purpose of this study was to quantify the contact state between Metha and the femur. Additionally, we investigated the difference in contact points between Meta and Fitmore, which is one of the more popular curved short stems.

Methods

We conducted a retrospective review of 42 hips that underwent THA using Metha and 41 hips using Fitmore. Stem-to-femur contact was evaluated by density mapping using a three-dimensional digital template system to quantify the contact condition according to the modified Gruen zone. The criterion for the stem-to-bone contact boundary was defined as a computed tomography value of 543 Hounsfield.

Results

Quantitative evaluation of Metha according to the modified Gruen zones showed the ratio of surface area with high cortical contact in each zone. The results were 4.6% ± 5.7% in zone 1, 0.9% ± 2.3% in zone 2, 19.1% ± 12.9% in zone 3, 1.4% ± 3.2% in zone 5, 29.6% ± 16.4% in zone 6, and 25.1% ± 17.7% in zones 7. Evaluation of Fitmore for the same zones was as follows: 1.6% ± 2.4%, 18.5% ± 16.9%, 20.8% ± 17.4%, 12.7% ± 12.8%, 3.7% ± 5.8%, and 13.3% ± 10.3%. Comparing the two groups, the contact area was significantly greater for Metha in zones 1, 6 and 7 and Fitmore in zones 2 and 5 (p < 0.05).

Conclusions

It is possible for Metha to achieve metaphyseal anchoring by contacting the cortical bone at the proximal femur, thus avoiding proximal offloading. To the best of our knowledge, no previous studies have quantitatively reported stem-to-cortical bone contact conditions in curved short stems.

Clinical and radiological outcomes of an uncemented metaphyseal short stem at minimum 10 years of follow-up: a prospective observational study

PURPOSE

There is growing interest around short stems as they provide a less invasive approach for total hip arthroplasty preserving bone stock for a possible revision surgery if required. The main purpose of this work was to assess the long-term performance of an uncemented metaphyseal short stem in terms of survival rate and in addition its clinical and radiological outcomes.

MATERIALS AND METHODS

From January to December 2010, we prospectively enrolled all consecutive patients undergoing primary total hip arthroplasty with an uncemented metaphyseal short stem in our institution with a minimum follow-up of 10 years. The radiographic features investigated were the varus-valgus stem orientation, areas of osteolysis and radiolucencies, stress shielding, and heterotopic calcifications. The clinical outcomes were measured using the HHS.

RESULTS

A total of 163 patients (172 hips) were finally included and the measured survival rate at 10 years was 99.6%. The average HHS increased from 55.0 preoperatively to 97.8 at the last follow-up (p < 0.0001). Among them, 137 patients (164 hips) were also available for radiographic assessment. Mild varus malalignment was observed in 40% of cases and remained stable in the serial X-rays and was not associated with step loosening. Mild stress shielding was observed around 13 stems (9%) and moderate only around 3 implants.

CONCLUSION

In conclusion, the uncemented metaphyseal short stems showed excellent survival and clinical results at 10 years and at a radiographical level very low stress shielding was observed; moreover, besides the high frequency of varus alignment the implanted stems was not associated with revision surgery or with worse clinical outcomes.

Short neck-preserving femoral stem for total hip arthroplasty: medium-term results of a 68-case series

INTRODUCTION

Short stems seem to be a good alternative for young patients as they offer promising results, rapid recovery and preservation of metaphyseal bone stock. This is one of the few studies in the literature to report medium-term clinical-radiological results for short hip stems.

MATERIALS AND METHODS

This prospective study evaluated 68 short femoral stems in 63 patients treated with total hip replacement. Clinical, functional and quality-of-life outcomes were measured at 6 and 12 months, and annually thereafter until the end of follow-up. The radiological analysis included measurements of potential leg length discrepancies, stem alignment and signs compatible with stress shielding.

RESULTS

Fifty-four males (59 hips) and nine females (9 hips) of an average age of 44.3 years (range, 25-68) were studied. The most common diagnosis was osteoarthritis (51.5%). Mean overall follow-up was 7.8 years (range, 5.8-9.8). The overall survival rate was 97.1% (95% CI 88.7-99.7%). Surgery resulted in an increase of 42.3 ± 1.1 points in the modified Harris Hip Score and 21.9 ± 0.6 points in the Oxford Hip Score (p < 0.001, respectively). Moreover, the pain score as measured on a numerical rating scale (NRS) improved from 95.8 to 36.3. As regards function, an improvement was observed from 3.2 ± 0.8 points to 6.8 ± 1.14 points on the University of California at Los Angeles activity score (p < 0.001, respectively). The radiological analysis showed an absence of radiolucencies or stress-shielding throughout the series. The complications rate at the end of follow-up was 5.7%.

CONCLUSIONS

The use of ultra-short cylindrical stems with complete anchorage in the femoral neck was shown to offer promising medium-term results. Such stems appear to be a good option for young patients, who are likely to require several revisions over their lifetime.

Minimally invasive anterolateral approach versus direct anterior approach total hip arthroplasty in the supine position: a prospective study based on early postoperative outcomes

BACKGROUND

Minimally anterolateral approach (MAA) and direct anterior approach (DAA) have been reported as beneficial for total hip arthroplasty (THA) due to their ability to reduce postoperative pain and lead to quicker rehabilitation by preserving muscle insertions. As there is an ongoing debate on the effect of these two approaches on early postoperative outcomes, this prospective study aimed to assess the difference in early clinical, radiological, and patient-reported outcomes between the two minimally invasive approaches.

METHODS

A total of 98 patients, 50 in the MAA group and 48 in the DAA group, were included in the study. Patients with complete data were evaluated preoperatively and postoperatively at 2, 6, and 12 weeks. Clinical measurements, including the ability to climb stairs and walk, 6-min walk test (6MWT), the Forgotten Joint Scale (FJS-12), Japanese Orthopedic Association (JOA) Hip scores, radiological evaluation, and complications were analyzed.

RESULTS

There were no significant differences in clinical outcomes and implant alignments between MAA and DAA groups. In regards to patient-reported outcomes, the FJS-12 was significantly higher in the MAA group compared to group DAA at 2 and 6 weeks postoperatively. However, there was no significant difference in the FJS-12 between the two groups 12 weeks after surgery. The differences also included shorter operative times (62.4 ± 9.05 min vs. 71 ± 8.01 min), less blood loss (132.6 ± 43.31 ml vs. 159.23 ± 37.25 ml), lower Hb drop (29.56 ± 8.02 g/L vs. 36.4 ± 7.12 g/L), and fewer blood transfusions in the MAA group (4.0% vs. 18.8%). The incidence of the lateral femoral cutaneous nerve (LFCN) neuropraxia after surgery was 7 (14.6%) in the DAA group and 0 in the MAA group. One fracture was found in each group and managed conservatively.

CONCLUSION

MAA and DAA approach yielded excellent and similar early clinical outcomes. However, better patient-reported outcomes could be achieved by MAA THA. The MAA resulted in a safer approach associated with shorter operative times, less blood loss, lower Hb drop, fewer blood transfusions, and LFCN neuropraxia than DAA. A longer follow-up is needed to further examine differences between these procedures.

Short Stem for Total Hip Arthroplasty (THA) - Overview, Patient Selection and Perspectives by Using the Metha® Hip Stem System

Short stem hip replacement has not only gained attention but also significance over the past decades. However, there still remains uncertainty regarding the correct indications for these stems. Even companies, producing implants, have varying recommendations that are more likely based on a well-meant advice than on statistically evaluated data. Thus, it is important to evaluate the advantages and disadvantages of a short stem prosthesis. The goal of this paper is to reveal some of the existing uncertainty in this field, by analyzing the Metha^® short hip stem system. This paper does not only focus on general aspects but also discusses some more specific problems, such as avascular necrosis and post-rheumatic diseases, as well as hip dysplasia and coxarthrosis. The aim is also to convey the opportunity to indicate this type of implant for elderly and obese patients as well as for femoral misalignments following post-Perthes disease, post-traumatic deformities or other malpositions of the hip.

Outcome and technical consideration of conversion total hip arthroplasty after failed fixation of intracapsular and extracapsular hip fractures: Are they really that different?

INTRODUCTION

Conversion Total Hip Arthroplasty (cTHA) is a rescue strategy for proximal femur osteosynthesis failures. However, it is unclear whether cTHAs performed for extra-capsular fracture fixation failures (ECF) or for intra-capsular fracture fixation failures (ICF) share the same complexity and efficacy. The purpose of our study was to compare cTHAs performed on pre-existing ICFs and pre-existing ECFs, focusing on surgical complications and functional outcomes in both groups.

METHODS

An observational retrospective study was conducted on cTHA patients, treated between 2014 and 2018, divided into 2 groups: ICF-group and ECF-group. The main outcomes were: type of implant used, duration of surgery, need for transfusions, incidence of complications, functional outcomes.

RESULTS

28 patients were included (15 in the ECF group and 13 in the ICF group); the average follow-up was of 31 ± 17.3 months. No significant differences were identified in terms of the type of implant used and duration of surgery. The number of transfused patients was 4 in the ICF group and 12 in the ECF group (p = 0.02); the average transfused units were 0.4 ± 0.7 in the ICF group and 1.3 ± 0.9 in the ECF group (p = 0.01). The incidence of complications - an infection and a dislocation, both of which occurred in the ICF group - and functional outcomes did not present significant differences.

CONCLUSION

The conversion surgery on ECFs patients is technically more difficult for the surgeon and prone to greater blood loss. The outcomes are satisfactory and overlap between the two groups.

Cementless Short Stems in Total Hip Arthroplasty: Chances and Limits

In recent decades, a large number of cementless short stems have been introduced to the market. The concept aims at saving soft tissue using minimally invasive surgery and at the same time preserving as much bone as possible. In particular, the latest generation of short stems, which are implanted using a calcar-guided round-the-corner technique, are attracting increasing attention. An individualised resection level allows individual stem alignment and thus an ideal reconstruction of the hip anatomy. The early clinical results of short-stem total hip arthroplasty (THA) are promising and have led to an expansion of the indications and limitations for the use of short stems. In particular, the individual positioning in valgus or varus and the resulting individual metaphyseal or metadiaphyseal anchorage offers various possibilities to reconstruct even abnormal joint morphologies. Consequently, short stems are increasingly used in patients with complex anatomical variations or in cases of osteonecrosis of the femoral head. In some various cases, they can also be used in revision or conversion arthroplasty. In some patients, short stems can also be used after femoral neck fracture. Currently, scientific data on those areas of indication of short-stem THA is scarce.

Future of total hip arthroplasty with the Metha short stem in modern surgeries

The aim of the study was to analyse the results of uncemented total hip replacement, using the Metha (metaphyseal) stem. A total of 158 patients (70 females and 88 males) were qualified to the study and submitted to total hip arthroplasty (183 procedures altogether), using the Metha stem. The mean age of the patients on the day of surgery was 51.7 years (the range from 17 to 69 years). The mean follow up period was 9.2 years (the range from 5 to 13.5 years). Preoperative assessments gave poor scores, according to the Merle d’Aubigne and Postel classification, modified by Charnley. The average improvement after surgery, according to the used scale, was 6.9 points. A very good outcome was recorded in 154 cases (84.2%), a good outcome was achieved in 20 cases (10.9%) and a poor outcome was confirmed in 9 cases, while no satisfactory case was observed. Poor outcomes were associated with implant loosening. Extraskeletal ossification was noted in 10 cases (5.5%). According to the Kaplan–Meier estimator, the 10-year survival was 93.2% and 97.3% for the whole implant and the stem alone, respectively. 1. Our follow-up period of more than 9 years on the average, indicates that Metha stems produce excellent clinical and functional results in operated young patients with advanced degenerative changes of the hip joint. 2. Assuming a proper qualification for the procedure, the absence of complications and a correct surgical technique, which is slightly more difficult, when compared to standard stem implantation, the risk of aseptic loosening is fairly negligible.

Total Hip Replacement in Developmental Hip Dysplasia: A Narrative Review

The reconstruction of the hip joint in patients suffering from developmental hip dysplasia (DDH) is a demanding procedure and presents many challenges to the reconstructive surgeon. Higher rates of mechanical complications are present in this group of patients. The results of cemented and uncemented implants used in DDH patients are very promising, according to recent outcomes. However, the surgeon has to be aware of several complications, in order to establish an uneventful surgical management of DDH. The specific article investigates the technical challenges and clinical results of total hip arthroplasty in patients with DDH.