Immediate weight bearing after uncemented total hip arthroplasty with an anteverted stem: a prospective randomized comparison using radiostereometry

Migration patterns of acetabular cups: a systematic review and meta-analysis of RSA studies

BACKGROUND AND PURPOSE

We conducted a systematic review and meta-analysis of RSA studies to investigate the early and long-term migration patterns of acetabular cups and the influence of implant factors on cup migration over time.

METHODS

We performed a systematic search of PubMed, Embase, and Scopus databases to identify all RSA studies of cup migration following primary total hip replacement (THR). Proximal migration at 3 and 6 months, 1, 2, 5, and 10 years were considered for analysis. Implant factors investigated included fixation type, head size, bearing surface, uncemented coating design, and the decade of RSA introduction.

RESULTS

47 studies reported the proximal migration of 83 cohorts (2,328 cups). Besides 1 threaded cup design, no implant factor investigated was found to significantly influence proximal migration. The mean pooled 2-year proximal migration of cemented cups (0.14 mm, 95% confidence interval [CI] 0.08-0.20) was not significantly different from uncemented cups (0.12 mm, CI 0.04-0.19). The mean pooled proximal migration at 6 months was 0.11 mm (CI 0.06-0.16) and there was no significant increase between 6 months and 2 years (0.015 mm, CI 0.000-0.030). 27 of 75 cohorts (36%) reported mean proximal migration greater than 0.2 mm at 2 years, which has previously been identified as a predictor of implants at risk of long-term loosening.

CONCLUSION

Our meta-analysis demonstrated that the majority of cup migration occurs within the first 6 months. With one exception, no implant factors influenced the 2-year proximal migration of acetabular cups. 36% of studies with 2-year migration were considered at risk of long-term loosening. Further investigation and comparison against long-term survivorship data would validate 6-month and/or 1-year proximal migration measurements as an earlier predictor of long-term loosening than the current 2-year threshold.

Early unrestricted vs. partial weight bearing after uncemented total hip arthroplasty: a systematic review and meta-analysis

Background

The choice of postoperative weight bearing protocol after uncemented total hip arthroplasty (THA) remains controversial. The aim of this study was to assess the efficacy and safety of immediate unrestricted weight bearing (UWB) compared with partial weight bearing (PWB) in patients undergoing uncemented THA.

Methods

Relevant articles were retrieved from electronic databases. Both randomized controlled trials (RCTs) and non-RCTs were included but analyzed separately. All functional and clinical outcomes with at least 2 independent study outcomes were meta-analyzed.

Results

A total of 17 studies were investigated. No adverse effect was found regarding micromotion of the femoral stem with immediate UWB following uncemented THA. There was also no correlation between immediate UWB and failure of ingrowth fixation and higher risks of femoral stem subsidence and surgical revision in RCTs. Harris hip score was better in patients with immediate UWB than those with PWB at 1 year post surgery, but the difference was not statistically significant.

Conclusions

Immediate UWB did not have extra harm compared with PWB in patients undergoing uncemented THA. UWB was not superior to PWB. Considering the improvement of Harris score and the compliance of patients, UWB can be encouraged in THA rehabilitation.

Total joint arthroplasty versus trapeziectomy in the treatment of trapeziometacarpal joint arthritis: a randomized controlled trial

The aim of this double anonymized, randomized controlled trial was to determine whether total joint arthroplasty has superior outcomes than trapeziectomy 1 year after surgery for trapeziometacarpal osteoarthritis. A total of 62 women aged 40 years and older, scheduled for surgery for stage II or III osteoarthritis of the trapeziometacarpal joint, were included and randomized to trapeziectomy or total joint arthroplasty. The primary outcome was the total score of the Michigan Hand Outcomes Questionnaire. Secondary outcomes were the Michigan Hand Outcomes Questionnaire subscale scores, Disability of the Arm, Shoulder and Hand Questionnaire, active range of motion, strength, return to work, patient satisfaction and complications. Data were collected at baseline and at 3 and 12 months. At 1 year, we found no superiority of total joint arthroplasty over trapeziectomy regarding the total score of the Michigan Hand Outcomes Questionnaire. The total joint arthroplasty did show a significant advantage in strength and range of motion.Level of evidence: I.

The Recovery of Weight-Bearing Symmetry After Total Hip Arthroplasty Is Activity-Dependent

This study aimed to characterize ipsilateral loading and return to weight-bearing symmetry (WBS) in patients undergoing total hip arthroplasty (THA) during activities of daily living (ADLs) using instrumented insoles. A prospective study in 25 THA patients was performed, which included controlled pre- and postoperative follow-ups in a single rehabilitation center of an orthopedic department. Ipsilateral loading and WBS of ADLs were measured with insoles in THA patients and in a healthy control group of 25 participants. Measurements in the THA group were performed at 4 different visits: a week pre-THA, within a week post-THA, 3–6 weeks post-THA, and 6–12 weeks post-THA, whereas the healthy control group was measured once. ADLs included standing comfortably, standing evenly, walking, and sit-to-stand-to-sit (StS) transitions. All ADLs were analyzed using discrete methods, and walking included a time-scale analysis to provide temporal insights in the ipsilateral loading and WBS waveforms. THA patients only improved beyond their pre-surgery levels while standing comfortably (ipsilateral loading and WBS, p < 0.05) and during StS transitions (WBS, p < 0.05). Nevertheless, patients improved upon their ipsilateral loading and WBS deficits observed within a week post-surgery across all investigated ADLs. Ipsilateral loading and WBS of THA patients were comparable to healthy participants at 6–12 weeks post-THA, except for ipsilateral loading during walking (p < 0.05) at the initial and terminal double-leg support period of the stance phase. Taken together, insole measurements allow for the quantification of ipsilateral loading and WBS deficits during ADLs, identifying differences between pre- and postoperative periods, and differentiating THA patients from healthy participants. However, post-THA measurements that lack pre-surgery assessments may not be sensitive to identifying patient-specific improvements in ipsilateral loading and WBS. Moreover, StS transitions and earlier follow-up time points should be considered an important clinical metric of biomechanical recovery after THA.

Efficacy and Safety of Lower Limb Progressive Resistance Exercise for Patients With Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate the efficacy and safety of progressive resistance exercise (PRE) for patients with total knee arthroplasty (TKA) in a meta-analysis.

DATA SOURCES

PubMed, MEDLINE, Cochrane's Library, and EMBASE databases.

STUDY SELECTION

Randomized controlled trials evaluating the effect of PRE on mobility and function in patients with TKA.

DATA EXTRACTION

A random-effects model was applied if significant heterogeneity was detected; otherwise, a fixed-effects model was applied.

DATA SYNTHESIS

Seven randomized controlled trials. Compared with a rehabilitation program without PRE, physiotherapy including PRE was associated with improvements in the 6-minute walking test (weighed mean difference [WMD], 19.22m; P=.04) with a wide confidence interval (CI, 0.48∼37.95). However, sensitivity analysis by omitting 1 study with preoperative rehabilitation revealed nonsignificant results (WMD, 15.15m; P=.16). Moreover, PRE did not significantly improve the maximal walking speed (WMD, 0.05m/s, 95% CI, 0.00∼0.11; P=.05). However, PRE was associated with improved knee strength of extension (standardized mean difference [SMD], 0.72; 95% CI, 0.47∼0.96; P<.001) and flexion (SMD, 0.47; 95% CI, 0.19∼0.74; P<.001) but not self-reported physical function (SMD, -0.17; 95% CI, -0.37∼0.03; P=.10) or changes in pain score (SMD, 0.11; 95% CI, -0.15∼0.37; P=.40). PRE did not increase the risk of adverse events (risk ratio, 1.19; 95% CI, 0.52∼2.71; P=.68).

CONCLUSIONS

PRE may lead to improvements in physical function among patients receiving a TKA. PRE leads to higher ultimate strength in the surgical knee and is safe to perform.

Good stability of a cementless, anatomically designed femoral stem in aging women: a 9-year RSA study of 32 patients

Background and purpose - We previously reported a transient, bone mineral density (BMD)-dependent early migration of anatomically designed hydroxyapatite-coated femoral stems with ceramic-ceramic bearing surfaces (ABG-II) in aging osteoarthritic women undergoing cementless total hip arthroplasty. To evaluate the clinical significance of the finding, we performed a follow-up study for repeated radiostereometric analysis (RSA) 9 years after surgery. Patients and methods - Of the 53 female patients examined at 2 years post-surgery in the original study, 32 were able to undergo repeated RSA of femoral stem migration at a median of 9 years (7.8-9.3) after surgery. Standard hip radiographs were obtained, and the subjects completed the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index outcome questionnaires. Results - Paired comparisons revealed no statistically significant migration of the femoral stems between 2 and 9 years post-surgery. 1 patient exhibited minor but progressive RSA stem migration. All radiographs exhibited uniform stem osseointegration. No stem was revised for mechanical loosening. The clinical outcome scores were similar between 2 and 9 years post-surgery. Interpretation - Despite the BMD-related early migration observed during the first 3 postoperative months, the anatomically designed femoral stems in aging women are osseointegrated, as evaluated by RSA and radiographs, and exhibit good clinical function at 9 years.

The Influence of Tribological Pairings and Other Factors on Migration Patterns of Short Stems in Total Hip Arthroplasty

Over the last decade, the number of short stem total hip arthroplasty procedures has increased. Along with the possible benefits associated with short stems is a smaller implant-bone contact surface, which may have a negative influence on primary stability and impair osseointegration. Previous studies observed migration of short stems, especially within the first three months. The variables that influence migration in short stem hip implants remain unknown. Therefore, the purpose of this study was to associate the migration of short stems with its possible influencing variables. Migration data from two different short stem studies were retrospectively analyzed. Migration within the first two postoperative years was determined by model-based Roentgen stereophotogrammetric analysis. Migration was correlated to bearing couple, type and size of stem, size of acetabular cup, and age, gender, weight, and height of patients using a multiple factor analysis. Eigenvalue analysis explained 80.7% of the overall variance for the first three dimensions. The four most dominant variables in the first dimension were weight, stem size, acetabular cup size, and patient height (correlations of 0.81, 0.80, 0.71, and 0.70, resp.). None of the analyzed parameters (bearing couple, type and size of stem, size of acetabular cup, and age, gender, weight, and height of patients) affected the migration pattern of short stem THA with primary metaphyseal fixation.

Partial versus early full weight bearing after uncemented total hip arthroplasty: a meta-analysis

BACKGROUND

This meta-analysis aimed to investigate the efficacy and safety of partial weight bearing (PWB) versus early full weight bearing (FWB) after uncemented total hip arthroplasty (THA).

METHODS

We conducted a search in PubMed, EMBASE, The Cochrane Library, and Web of Science for randomized controlled trials (RCTs) and non-RCTs comparing PWB and early FWB after uncemented THA. Two authors conducted the selection of studies, data extraction, and assessment of risk of bias independently. A pooled meta-analysis was performed using the RevMan 5.3 software.

RESULTS

Six RCTs and three non-RCTs met the inclusion criteria. The meta-analysis indicated that compared with PWB, the FWB group showed greater femoral subsidence at 3-month follow-up (MD = -0.12, 95% CI -0.22 to -0.01, P = 0.03). There were no significant differences in the hip Harris score at 1-year and 2-year follow-up (MD = 1.54, 95% CI -0.83 to 3.90, P = 0.20; MD = 0.08, 95% CI -1.19 to 1.34, P = 0.90, respectively), in femoral subsidence at 2-year follow-up and at two additional years of follow-up (MD = -0.03, 95% CI -0.31 to 0.25, P = 0.84; (MD = -0.02, 95% CI -0.37 to 0.33, P = 0.91, respectively). There were no significant differences in the incidences of bone ingrowth fixation, spot welds, and radiolucent lines.

CONCLUSIONS

This meta-analysis shows that early FWB in patients with uncemented THA could be safe and could not increase the incidence of postoperative complications.

One-stage bilateral versus unilateral short-stem total hip arthroplasty: comparison of migration patterns using "Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis"

PURPOSE

The hypothesis of this study was that femoral implant migration would not differ between simultaneous bilateral or unilateral short-stem THA.

METHOD

Implant migration of 202 femoral short-stems (100 unilateral and 102 one-stage bilateral cases) in 151 patients was assessed by "Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis" in a two years follow-up (2.0-3.0 years). Migration patterns of unilateral and simultaneous cases were analysed and compared.

RESULTS

There was no difference between the two groups regarding age, body mass index and gender. After two years mean subsidence of all 202 implants was 1.43 mm (-6.5 mm to 2.0 mm). After initial subsidence of 0.37 mm per month within the first six weeks, the mean monthly migration was reduced to 0.02 mm between one and two years post-operative. There was no statistical difference in mean migration between unilateral (1.34 mm) and simultaneous bilateral (1.51 mm) THA (p = 0.33).

CONCLUSION

In summary, two years post-operative there was no difference in the amount of mean implant subsidence between unilateral compared to simultaneous bilateral short-stem THA. This suggests that regarding implant fixation simultaneous bilateral short-stem THA is as safe and successful as a solely unilateral intervention.

Total hip arthroplasty in an outpatient setting in 27 selected patients

BACKGROUND AND PURPOSE

As a result of introduction of a fast-track program, length of hospital stay after total hip arthroplasty (THA) decreased in our hospital. We therefore wondered whether THA in an outpatient setting would be feasible. We report our experience with THA in an outpatient setting.

PATIENTS AND METHODS

In this prospective cohort study, we included 27 patients who were selected to receive primary THA in an outpatient setting between April and July 2014. Different patient-reported outcome measures (PROMs) were recorded preoperatively and at 6 weeks and 3 months postoperatively. Furthermore, anchor questions on how patients functioned in daily living were scored at 6 weeks and 3 months postoperatively.

RESULTS

3 of the 27 patients did not go home on the day of surgery because of nausea and/or dizziness. The remaining 24 patients all went home on the day of surgery. PROMs improved substantially in these patients. Moreover, anchor questions on how patients functioned in their daily living indicated that the patients were satisfied with the postoperative results. 1 re-admission occurred at 11 days after surgery because of seroma formation. There were no other complications or reoperations.

INTERPRETATION

At our hospital, with a fast-track protocol, outpatient THA was found to be feasible in selected patients with satisfying results up to 3 months postoperatively, without any outpatient procedure-specific complications or re-admissions.

Early subsidence of shape-closed hip arthroplasty stems is associated with late revision. A systematic review and meta-analysis of 24 RSA studies and 56 survival studies

BACKGROUND AND PURPOSE

Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral stems.

PATIENTS AND METHODS

Of the 2 reviews, one covered early migration data obtained from radiostereometric analysis (RSA) studies and the other covered long-term aseptic revision rates obtained from survival studies with endpoint revision for aseptic loosening. Stems were stratified according to the design concept: cemented shape-closed, cemented force-closed, and uncemented. A weighted regression model was used to assess the association between early migration and late aseptic revision, and to correct for confounders. Thresholds for acceptable and unacceptable migration were determined in accordance with the national joint registries (≤ 5% revision at 10 years) and the NICE criteria (≤ 10% revision at 10 years).

RESULTS

24 studies (731 stems) were included in the RSA review and 56 studies (20,599 stems) were included in the survival analysis review. Combining both reviews for the 3 design concepts showed that for every 0.1-mm increase in 2-year subsidence, as measured with RSA, there was a 4% increase in revision rate for the shape-closed stem designs. This association remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. The threshold for acceptable migration of shape-closed designs was defined at 0.15 mm; stems subsiding less than 0.15 mm in 2 years had revision rates of less than 5% at 10 years, while stems exceeding 0.15 mm subsidence had revision rates of more than 5%.

INTERPRETATION

There was a clinically relevant association between early subsidence of shape-closed femoral stems and late revision for aseptic loosening. This association can be used to assess the safety of shape-closed stem designs. The published research is not sufficient to allow us to make any conclusions regarding such an association for the force-closed and uncemented stems.

Can Early Rehabilitation after Total Hip Arthroplasty Reduce Its Major Complications and Medical Expenses? Report from a Nationally Representative Cohort

Objective. To investigate whether early rehabilitation reduces the occurrence of posttotal hip arthroplasty (THA) complications, adverse events, and medical expenses within one postoperative year. Method. We retrospectively retrieve data from Taiwan's National Health Insurance Research Database. Patients who had undergone THA during the period from 1998 to 2010 were recruited, matched for propensity scores, and divided into 2 groups: early rehabilitation (Early Rehab) and delayed rehabilitation (Delayed Rehab). Results. Eight hundred twenty of 999 THA patients given early rehabilitation treatments were matched to 205 of 233 THA patients given delayed rehabilitation treatments. The Delayed Rehab group had significantly (all p < 0.001) higher medical and rehabilitation expenses and more outpatient department (OPD) visits than the Early Rehab group. In addition, the Delayed Rehab group was associated with more prosthetic infection (odds ratio (OR): 3.152; 95% confidence interval (CI): 1.211–8.203; p < 0.05) than the Early Rehab group. Conclusions. Early rehabilitation can significantly reduce the incidence of prosthetic infection, total rehabilitation expense, total medical expenses, and number of OPD visits within the first year after THA.

A randomised trial comparing a short and a standard-length metaphyseal engaging cementless femoral stem using radiostereometric analysis

This was a randomised controlled trial studying the safety of a new short metaphyseal fixation (SMF) stem. We hypothesised that it would have similar early clinical results and micromovement to those of a standard-length tapered Synergy metaphyseal fixation stem. Using radiostereometric analysis (RSA) we compared the two stems in 43 patients. A short metaphyseal fixation stem was used in 22 patients and a Synergy stem in 21 patients. No difference was found in the clinical outcomes pre- or post-operatively between groups. RSA showed no significant differences two years post-operatively in mean micromovement between the two stems (except for varus/valgus tilt at p = 0.05) (subsidence 0.94 mm (sd 1.71) vs 0.32 mm (sd 0.45), p = 0.66; rotation 0.96° (sd 1.49) vs 1.41° (sd 2.95), p = 0.88; and total migration 1.09 mm (sd 1.74) vs 0.73 mm (sd 0.72), p = 0.51). A few stems (four SMF and three Synergy) had initial migration > 1.0 mm but stabilised by three to six months, with the exception of one SMF stem which required revision three years post-operatively. For most stems, total micromovement was very low at two years (subsidence < 0.5 mm, rotation < 1.0°, total migration < 0.5 mm), which was consistent with osseous ingrowth. The small sample makes it difficult to confirm the universal applicability of or elucidate the potential contraindications to the use of this particular new design of stem.

Cite this article: Bone Joint J 2015; 97-B:595–602.

Adherence of hip and knee arthroplasty studies to RSA standardization guidelines. A systematic review

BACKGROUND AND PURPOSE

Guidelines for standardization of radiostereometry (RSA) of implants were published in 2005 to facilitate comparison of outcomes between various research groups. In this systematic review, we determined how well studies have adhered to these guidelines.

METHODS

We carried out a literature search to identify all articles published between January 2000 and December 2011 that used RSA in the evaluation of hip or knee prosthesis migration. 2 investigators independently evaluated each of the studies for adherence to the 13 individual guideline items. Since some of the 13 points included more than 1 criterion, studies were assessed on whether each point was fully met, partially met, or not met.

RESULTS

153 studies that met our inclusion criteria were identified. 61 of these were published before the guidelines were introduced (2000-2005) and 92 after the guidelines were introduced (2006-2011). The methodological quality of RSA studies clearly improved from 2000 to 2011. None of the studies fully met all 13 guidelines. Nearly half (43) of the studies published after the guidelines demonstrated a high methodological quality and adhered at least partially to 10 of the 13 guidelines, whereas less than one-fifth (11) of the studies published before the guidelines had the same methodological quality. Commonly unaddressed guideline items were related to imaging methodology, determination of precision from double examinations, and also mean error of rigid-body fitting and condition number cutoff levels.

INTERPRETATION

The guidelines have improved methodological reporting in RSA studies, but adherence to these guidelines is still relatively low. There is a need to update and clarify the guidelines for clinical hip and knee arthroplasty RSA studies.

Task-oriented exercises and early full weight-bearing contribute to improving disability after total hip replacement: a randomized controlled trial

OBJECTIVE

To evaluate the efficacy of an in-hospital programme based on task-oriented exercises associated with early full weight-bearing in patients with multiple comorbidities undergoing total hip replacement.

DESIGN

Randomized controlled trial.

SETTING

Specialised rehabilitation centre.

SUBJECTS

A total of 100 patients (mean age of 69 (8) years; 40 males, 60 females).

INTERVENTIONS

The experimental group underwent task-oriented exercises and was encouraged to abandon any walking aids by the end of their in-hospital stay. The control group underwent open chain kinetic exercises, and was recommended to use partial weight-bearing and walking aids until three months after surgery. Both groups individually followed programmes of 90-minute sessions five times a week for three weeks.

OUTCOME MEASURES

Western Ontario and McMaster Universities Osteoarthritis Index, Pain Numerical Rating Scale, Functional Independence Measure, and Short-Form Health Survey. The participants were evaluated before, after training, and after a further 12 months.

RESULTS

There were no significant between-group differences at baseline. After training, a between-group difference of 12 points was found for the Western Ontario and McMaster Universities Osteoarthritis Index - functional subscale, indicating a clinically tangible treatment effect on disability. The Functional Independence Measure increased by 31 and 15 points in the experimental and control group, respectively. A linear mixed model revealed significant effects of time, group, and time by group interaction on disability, pain, activities of daily living, and most of the physical quality of life domains.

CONCLUSION

Task-oriented exercises associated with early full weight-bearing improve disability, pain, activities of daily living, and quality of life after total hip replacement.

Small and similar amounts of micromotion in an anatomical stem and a customized cementless femoral stem in regular-shaped femurs. A 5-year follow-up randomized RSA study

BACKGROUND AND PURPOSE

High primary stability is important for long-term survival of uncemented femoral stems. Different stem designs are currently in use. The ABG-I is a well-documented anatomical stem with a press-fit design. The Unique stem is designed for a tight customized fit to the cortical bone of the upper femur. This implant was initially developed for patients with abnormal anatomy, but the concept can also be used in patients with normal femoral anatomy. We present 5-year radiostereometric analysis (RSA) results from a randomized study comparing the ABG-I anatomical stem with the Unique femoral stem.

PATIENTS AND METHODS

100 hips with regular upper femur anatomy were randomized to either the ABG-I stem or the Unique femoral stem. RSA measurements were performed postoperatively and after 3, 6, 12, 24, and 60 months.

RESULTS

RSA measurements from 80 hips were available for analysis at the 5-year follow-up. Small amounts of movement were observed for both stems, with no statistically significant differences between the 2 types.

INTERPRETATION

No improvement in long-term stability was found from using a customized stem design. However, no patients with abnormal geometry of the upper femur were included in this study.

What does standard rehabilitation practice after total hip replacement in the UK entail? Results of a mixed methods study

Background

There is evidence of prolonged poor function in patients following total hip replacement (THR). Studies of progressive resistance training (PRT) interventions to improve function are often compared to ‘standard’ practice which is not well defined. This study aimed to investigate ‘standard’ rehabilitation care in the UK after total hip replacement (THR) as well as determine whether PRT was part of ‘standard’ care.

Methods

After ethical approval, questionnaire item development about rehabilitation practice was guided by a focus group interview (after informed consent) with physiotherapists (n = 4; >5 years post-qualification) who regularly treated THR patients. An online questionnaire investigating the exercises prescribed and rehabilitation practice following THR was developed and sent to physiotherapists working in hospitals in the UK. The survey was performed from January to May 2011. The survey results were analysed (frequency (%) of responses) focusing on the exercises the physiotherapists considered important, as well as their use of PRT in prescribed regimes.

Results

106 responses were obtained from physiotherapists in the UK. The survey respondents considered that the most important muscles to target in all phases of rehabilitation were the hip abductors (62.2%), followed by the quadriceps (16.9%), and other muscles (21%). Exercise type prescribed revealed no consensus, with weight bearing (42%), functional (45%) and Bed-based/Bridging/Postural exercises (13%) favoured. 83.7% were able to define the basis of progressive resistance training (PRT), but only 33% prescribed it.

Conclusions

Standard physiotherapy rehabilitation in the UK after THR is variable, and appears to rarely include PRT. This may be a factor in prolonged poor function in some patients after this common operation.

A prospective cohort study on the short collum femoris-preserving (CFP) stem using RSA and DXA. Primary stability but no prevention of proximal bone loss in 27 patients followed for 2 years

BACKGROUND AND PURPOSE

Short femoral stems have been introduced in total hip arthroplasty in order to save proximal bone stock. We hypothesized that a short stem preserves periprosthetic bone mineral density (BMD) and provides good primary stability.

METHODS

We carried out a prospective cohort study of 30 patients receiving the collum femoris-preserving (CFP) stem. Preoperative total hip BMD and postoperative periprosthetic BMD in Gruen zones 1-7 were investigated by dual-energy x-ray absorptiometry (DXA), stem migration was analyzed by radiostereometric analysis (RSA), and the Harris hip score (HHS) was determined.

RESULTS

2 patients were excluded intraoperatively and 1 patient was revised due to a deep infection, leaving 27 patients for analysis. The mean HHS increased from 49 (24-79) preoperatively to 99 (92-100) after 2 years. DXA after 1 year showed substantial loss of BMD in Gruen zone 7 (-31%), zone 6 (-19%), and zone 2 (-13%, p < 0.001) compared to baseline BMD determined immediately postoperatively. The bone loss in these regions did not recover after 2 years, whereas the more moderate bone loss in Gruen zones 1, 3, and 5 partially recovered. There was a correlation between low preoperative total hip BMD and a higher amount of bone loss in Gruen zones 2, 6 and 7. RSA showed minor micromotion of the stem: mean subsidence was 0.13 (95% CI: -0.28 to 0.01) mm and mean rotation around the longitudinal axis was 0.01º (95% CI: -0.1 to 0.39) after 2 years.

INTERPRETATION

We conclude that substantial loss in proximal periprosthetic BMD cannot be prevented by the use of a novel type of short, curved stem, and forces appear to be transmitted distally. However, the stems showed very small migration-a characteristic of stable uncemented implants.

Early proximal migration of cups is associated with late revision in THA: a systematic review and meta-analysis of 26 RSA studies and 49 survivalstudies

BACKGROUND AND PURPOSE

The association between excessive early migration of acetabular cups and late aseptic revision has been scantily reported. We therefore performed 2 parallel systematic reviews and meta-analyses to determine the association between early migration of acetabular cups and late aseptic revision.

METHODS

One review covered early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were classified according the Swedish Hip Arthroplasty Register and the Australian National Joint Replacement Registry: < 5% revision at 10 years.

RESULTS

Following an elaborate literature search, 26 studies (involving 700 cups) were included in the RSA review and 49 studies (involving 38,013 cups) were included in the survival review. For every mm increase in 2-year proximal migration, there was a 10% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, proximal migration of up to 0.2 mm was considered acceptable and proximal migration of 1.0 mm or more was considered unacceptable. Cups with proximal migration of between 0.2 and 1.0 mm were considered to be at risk of having revision rates higher than 5% at 10 years.

INTERPRETATION

There was a clinically relevant association between early migration of acetabular cups and late revision due to loosening. The proposed migration thresholds can be implemented in a phased evidence-based introduction, since they allow early detection of high-risk cups while exposing a small number of patients.

Migration analysis of a metaphyseal anchored short-stem hip prosthesis

BACKGROUND AND PURPOSE

Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA).

PATIENTS AND METHODS

First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score.

RESULTS

After 2.7 (2.0-4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3-1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0).

INTERPRETATION

The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement.

Low BMD affects initial stability and delays stem osseointegration in cementless total hip arthroplasty in women: a 2-year RSA study of 39 patients

BACKGROUND AND PURPOSE

Immediate implant stability is a key factor for success in cementless total hip arthroplasty (THA). Low bone mineral density (BMD) and age-related geometric changes of the proximal femur may jeopardize initial stability and osseointegration. We compared migration of hydroxyapatite-coated femoral stems in women with or without low systemic BMD.

PATIENTS AND METHODS

61 female patients with hip osteoarthritis were treated with cementless THA with anatomically designed hydroxyapatite-coated femoral stems and ceramic-ceramic bearing surfaces (ABG-II). Of the 39 eligible patients between the ages of 41 and 78 years, 12 had normal systemic BMD and 27 had osteopenia or osteoporosis. According to the Dorr classification, 21 had type A bone and 18 had type B. Translational and rotational migration of the stems was evaluated with radiostereometric analysis (RSA) up to 2 years after surgery.

RESULTS

Patients with low systemic BMD showed higher subsidence of the femoral stem during the first 3 months after surgery than did those with normal BMD (difference = 0.6, 95% CI: 0.1-1.1; p = 0.03). Low systemic BMD (odds ratio (OR) = 0.1, CI: 0.006-1.0; p = 0.02), low local hip BMD (OR = 0.3, CI: 0.1-0.7; p = 0.005) and ageing (OR = 1.1, CI: 1.0-1.2; p = 0.02) were risk factors for delayed translational stability. Ageing and low canal flare index were risk factors for delayed rotational stabilization (OR = 3, CI: 1.1-9; p = 0.04 and OR = 1.1, CI: 1.0-1.2; p = 0.02, respectively). Harris hip score and WOMAC score were similar in patients with normal systemic BMD and low systemic BMD.

INTERPRETATION

Low BMD, changes in intraosseous dimensions of the proximal femur, and ageing adversely affected initial stability and delayed osseointegration of cementless stems in women.

The effects of different weight-bearing regimes on press-fit cup stability: a randomised study with five years of follow-up using radiostereometry

PURPOSE

There is little evidence to support immediate weight bearing after uncemented total hip arthroplasty (THA).

METHODS

Thirty-seven patients with unilateral osteoarthritis of the hip received a press-fit cup. Cup stability was assessed with radiostereometry (RSA) over five years. Patients were randomised to immediate full weight bearing, or partial weight bearing for three months.

RESULTS

At five years, we found no difference in micro-motion as assessed with radiostereometry. Numerically, there was more proximal translation and increased inclination with immediate weight bearing, but these values barely exceeded the precision limit for the method. Pooled data for the two groups revealed translations of 0.1-0.3 mm and rotations of 0.2-0.3° over the five year follow-up period.

CONCLUSIONS

We found no adverse effects of immediate weight bearing after THA in relation to stability of these press-fit cups. Early mobilisation might have other advantages.

Is there an increased stem migration or compromised osteointegration of the Mayo short-stemmed prosthesis following cerclage wiring of an intrasurgical periprosthetic fracture?

AIM

Short-stemmed prostheses are increasingly regarded as implants of first choice in primary THA. As a result of the press-fit fixation in the femoral metaphysis, the occurrence of intraoperative fractures were reported. The aim of this study was to analyze the postoperative results of the Mayo short-stem prosthesis following treatment of an intrasurgical femur fracture with cerclage wiring.

PATIENTS AND METHODS

From 1999 to 2005, in 38 patients (18 females, 20 males; mean age 56 years; mean BMI = 27) with the diagnosis of coxarthrosis in whom a Mayo short-stemmed prosthesis has been implanted, an intraoperative fracture was observed. The fractures were treated with cerclage wiring (1 cerclage, n = 32; 2 cerclages, n = 5; 3 cerclages, n = 1). Postoperatively, all patients were prescribed mobilization without weight-bearing (floor contact) on the treated leg for 6 weeks. Using the Wristing software, longitudinal stem migration and varus-valgus femoral stem alignment were examined digitally in anteroposterior X-rays taken immediately after surgery, after 6 weeks and on average after 5.7 years (Zeh et al., Z Orthop Unfall 149:200-205, 2011). Additionally, the incidence of periprosthetic radiolucent lines was captured in the anteroposterior X-rays and assigned to the Gruen zones. Additionally, a DEXA scan was performed. The X-rays of a matched control group after the implantation of a Mayo prosthesis without femur fracture were analyzed by the same method.

RESULTS

There was no significant migration of the Mayo prosthesis in the study or control groups during postoperative follow-up (t test, P > 0.05). The cerclage group compared with the control group showed a statistically significant valgus tilt of 1.5° on average during the follow-up, which is regarded to be clinically not relevant. The frequency of occurrence of radiolucent lines was not statistically different (chi-square test, χ = 0.42, P = 0.51). DEXA scans showed no differences of the bone mineral density in the Gruen zones compared with a historical control group.

CONCLUSION

After wiring of an intrasurgical fracture, no disadvantage could be proven for Mayo prosthesis regarding stem migration and varus-valgus alignment. Furthermore, due to the absence of differences in the occurrence of radiolucent lines and the same results in the DEXA scan, an unimpaired osseointegration is assumed.

A prospective randomized study comparing electrochemically deposited hydroxyapatite and plasma-sprayed hydroxyapatite on titanium stems

BACKGROUND AND PURPOSE

Plasma-sprayed hydroxyapatite (HA) is a successful coating for fixation of uncemented femoral stems. There may be alternative coatings with advantages in bone remodeling and transport of bone-active substances. We investigated whether an electrochemically deposited hydroxyapatite, Bonemaster (BM), might be a safe alternative in total hip arthroplasty. Our hypothesis was that the new coating would not be inferior to the conventional one.

PATIENTS AND METHODS

50 patients (55 hips) were included. The stem was tapered and porous-coated proximally. On top of the porous coating was either HA or BM. Patients were evaluated postoperatively and after 3, 6, 12, and 24 months to measure fixation by radiostereometric analysis (RSA), bone mineral density by dual-energy X-ray absorptiometry (DXA), and conventional radiography. Clinical evaluation was performed with Harris hip score and Oxford hip score, both preoperatively and after 2 years.

RESULTS

After 2 years, the stems had subsided 0.25 (HA) and 0.28 (BM) mm and there were no statistically significant differences between the groups in any direction, regarding both migration and rotation. The BM group retained significantly more bone than the HA group in Gruen zone 1 during the first 2 years. The Harris and Oxford hip scores were similar in both groups.

INTERPRETATION

Electrochemically deposited hydroxyapatite on an uncemented stem does not appear to be inferior to plasma-sprayed HA regarding clinical and radiological results, bone remodeling, and micromotion after 2 years follow-up.

The optimal timing of baseline radiostereometric analysis of uncemented press fit cups

BACKGROUND AND AIMS

The baseline radiostereometric analysis (RSA) is usually performed during the first postoperative week. We investigated the micromotion of two uncemented press fit acetabular cups during the first week after total hip arthroplasty.

MATERIAL AND METHODS

All study patients had unilateral osteoarthritis of the hip and received an uncemented THA combination consisting of a CLS stem and either an Allofit or an Interop acetabular cup. The study group consisted of 24 patients who underwent RSA within 1 hour after skin closure, and at 1 and 7 days after surgery.

RESULTS

The upper limit of the 95% confidence interval for micromotion was less than or close to the precision of the method for all studied directions during the first week after surgery. Mean values indicate proximal and medial translation of the uncemented cup at one week.

CONCLUSIONS

We found only minimal micromotion, barely above the precision limit, measured as medial and proximal translations of these uncemented cups. This indicates that the first postoperative RSA measurement following a primary THA with an uncemented press fit ace-tabular cup should be made as early as possible after the first postoperative day.

Partial weightbearing is not necessary after cementless total hip arthroplasty: a two-year prospective randomized study on 100 patients

The purpose of this study was to evaluate the effects of partial and full weightbearing after cementless total hip arthroplasty over a two year follow-up period. Fifty-nine women and 41 men (average age 61 years) received an uncemented Spotorno stem and were randomised into a full and a partial weightbearing group. No significant difference was found between the groups with regard to the Merle d' Aubigne hip score, VAS pain level, shaft migration or radiographic signs of bony ingrowth. All femoral components seemed radiologically well-fixed and showed bone ingrowth at 24 months. Provided that solid initial fixation is obtained full weightbearing immediately after cementless total hip arthroplasty using a hydroxyapatite-coated Spotorno-type femoral shaft component can be recommended.

Periprosthetic bone mineral density and fixation of the uncemented CLS stem related to different weight bearing regimes: A randomized study using DXA and RSA in 38 patients followed for 5 years

BACKGROUND AND PURPOSE

There is no consensus on the best rehabilitation regime after uncemented total hip arthroplasty. Theoretically, bone ingrowth into the implant should benefit from initial partial weight bearing. We investigated whether the degree of postoperative weight bearing influences the periprosthetic bone mineral density (BMD) and/or the stability of the CLS stem.

PATIENTS AND METHODS

38 patients received an uncemented CLS stem and were randomized to either unrestricted postoperative weight bearing or to partial weight bearing for 3 months. Periprosthetic BMD was measured in the 7 Gruen zones with DXA and the stability of the femoral stem was assessed by radiostereometric analysis (RSA) after surgery and at 3, 12, 24, and 60 months.

RESULTS

Periprosthetic BMD was not influenced by the type of postoperative weight bearing. BMD was reduced by 8-15% in all Gruen zones at 3 months. Restoration toward initial BMD was observed in all zones except in zone 7 (calcar region), where BMD was reduced by 22% at 5 years. Immediate weight bearing after surgery had no influence on the stability of the CLS stem, as assessed by RSA.

INTERPRETATION

Immediate full weight bearing after uncemented total hip arthroplasty is safe. There is no difference in the periprosthetic BMD or in stability of the stem as measured by RSA compared to partial weight bearing for 3 months. BMD is reduced by more than 20% in the calcar region around a CLS stem after 5 years.

[Partial weight-bearing in rehabilitation. Strategies for instruction and limitations]

Following trauma or surgery on the musculoskeletal system the primary aim is always as complete a restitution of mobility as possible. By mobilization with partial weight-bearing this is possible. The preferred way of teaching partial weight-bearing is the use of conventional bathroom scales. This method proves to be simple as well as time and cost-saving, but the transferability to the patient's daily life is questionable. Training and control of partial weight-bearing under dynamic conditions, such as normal walking, and walking up and down stairs seem to be very important. Different investigations have shown that the minority of subjects recruited could manage to maintain the given load of partial weight-bearing. Furthermore, the actual resulting moments within the joints, caused by muscles, fascia and tendons, are not considered in presets of partial weight-bearing, as only external forces (ground reaction forces) are measured. However, the problems in teaching partial weight-bearing have to be contrasted with the as yet unexplained issue of postoperative partial versus full weight-bearing.

Partial versus unrestricted weight bearing after an uncemented femoral stem in total hip arthroplasty: recommendation of a concise rehabilitation protocol from a systematic review of the literature

The aim of this systematic review was to find evidence-based support in the literature to allow immediate unrestricted weight bearing after primary uncemented total hip arthroplasty (THA). Accelerated rehabilitation programs for THA are becoming increasingly popular to shorten hospital stay and to facilitate rapid restoration of function. The goals of these rehabilitation programs could be more easily achieved if immediate unrestricted weight bearing (UWB) could be allowed after a THA. So far, however, immediate weight bearing is frequently contraindicated in widely accepted protocols for uncemented THA due to fear for subsidence and absence of osseous integration of the femoral stem. Thus, frequently protected weight bearing and restricted activities are still advocated for at least 6 weeks after surgery. In addition, we analyzed the literature to come to a recommendation on gait pattern and walking aid. From a systematic search in several electronic databases 13 studies met the inclusion criteria. These studies were reviewed according to the Cochrane methodology. We found moderate to strong evidence that no adverse effects on subsidence and osseous integration of the femoral stem after uncemented THA occur after immediate UWB. Based on this literature review, we recommend early rehabilitation after uncemented THA with a reciprocally gait pattern using crutches, one cane for independency in ADL in case patients walk limp-free and walking without crutches as soon as possible. During the first weeks after surgery only stair climbing should be performed with protected weight bearing because of high torsion loads on the hip.

Pilates training for use in rehabilitation after total hip and knee arthroplasty: a preliminary report

Recently, a strong emphasis has been placed on establishing rehabilitation protocols after primary total hip and knee arthroplasty in an attempt to shorten, improve, and standardize the postoperative period of recovery. Less invasive surgical techniques, patient demands, and the pressure of insurance regulations have forced postoperative rehabilitation to be placed on an expedited scale. With these concerns in mind, we introduce a pre- and postarthroplasty program involving the Pilates method. Modified exercises have been developed to account for the postoperative precautions and needs of total hip and knee arthroplasty patients. A patient-driven interest in the use of Pilates for postoperative rehabilitation has led to the development of our programs following total hip or knee arthroplasty. In reviewing our early observations of a small series of patients, it appears this technique can be utilized without early complications; however, further studies are necessary to confirm its utility and safety.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.