HIP International最新文献

Background: There are variations in the performance of individual prostheses used in hip replacements. Some of which have unexpectedly higher revision rates - outliers. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) has established a standardised multi-stage approach for identifying these devices. This is done by comparing the revision rates of individual prostheses to all other prostheses in class, with the exception of large head metal-on-metal (LHMoM) prostheses. However, improvements in device design and performance over time have required a need to reconsider the comparator group. This study aimed to identify a more specific comparator to better reflect contemporary surgical practice.

Methods: The time to first revision was estimated on the data of 413,417 primary total conventional hip replacements undertaken for osteoarthritis (OA) from 01 January 2003 to 31 December 2019. Survivorship analyses with stepwise exclusions were undertaken. The first exclusion was LHMoM, followed by other non-modern bearing surfaces (defined as all the bearing couples except metal or ceramic heads on cross-linked polyethylene and mixed ceramic-on-ceramic), and then devices with modular neck-stem design or used for specific purposes (incl. constrained, dual-mobility, and head size <28 mm). Lastly, all remaining prostheses previously identified as having a higher than anticipated rate of revision (HTARR) were also excluded.

Results: These exclusions progressively reduced the cumulative percent revision (CPR) rate. The final comparator, which only includes satisfactory-performed prostheses of contemporary design and use, has a 10-year CPR of 4.30% (95% CI, 4.2-4.41) which is lower than 4.93% (95% CI, 4.84-5.02) for the current comparator used by the AOANJRR (all prostheses excluding LHMOM). Over the study period, 13 additional components were identified utilising the modified comparator.

Conclusions: The calculation of the comparator revision rate should be re-evaluated to include only modern prosthesis constructs to ensure that poorly performing prostheses are identified early.

Background: Restoring hip anatomy during total hip arthroplasty (THA) is the gold standard. The general goal is for hips to be symmetrical in terms of height. This study aimed to analyse the effect of simulating hip length (HL) equalisation on leg-length difference (LLD) before and after THA with a computerised plan.

Methods: 141 consecutive patients were enrolled following THA. Outcomes of interest were preoperative hip-length difference (HLD) and LLD as determined on CT and final LLD as determined by simulating HL equalisation. We divided patients into 3 groups: no LLD, LLD >5 mm and LLD ⩾10 mm.

Results: The rate of preoperative LLD >5 mm and LLD ⩾10 mm was 37.5% and 14.8%, respectively. HL equalisation did not change LLD distribution in the overall cohort. Among patients with smaller preoperative HLs and LLDs, HL equalisation changed the rate of LLD >5 mm from 100% (n = 24) to 41.7% (n = 10) (p < 0.0001) and of LLD ⩾10 mm from 100% (n = 12) to 16.7% (n = 2) (p < 0.0001). Among patients with no preoperative LLD, HL equalisation changed the rate of LLD ⩽5 mm from 100% (n = 64) to 59.3% (n = 38) (p < 0.0001) and of LLD<10 mm from 100% (n = 76) to 89.5% (n = 68) (p = 0.006).

Conclusions: Restoring biomechanical hip anatomy by HL equalisation may not be the correct goal for all patients. In patients with no LLD and shorter HLs, equalisation could result in LLD >5 mm in 40% of patients and LLD >10 mm in 10%, demonstrating the necessity to further analyse individuals and propose a personalised stem position.

Background: The alpha angle has been widely used in the assessment of cam-type of impingement, but recent studies have shown that this angle may also be high in asymptomatic patients. The aim of this study is to report the prevalence of cam-type morphology in asymptomatic volunteers and explore its correlation with hip clinical and radiological parameters.

Methods: This single-centre prospective study included 48 asymptomatic male volunteers (96 hips). All candidates fulfilled the inclusion and exclusion criteria. Physical examination and 1.5 -T MRI imaging were done for bilateral hips on the same day. Alpha angle measurements were obtained from 4 different positions and cam-type morphology was considered positive using 2 different cut points >55° and >60°. Descriptive statistics were analysed and correlations were performed where appropriate and p-value < 0.05 was considered to be significant.

Results: The prevalence of cam-type morphology using alpha angle >55° was 68.8%, 87.5%, 50% and 34.4% in the 12, 1, 2 and 3 o'clock positions respectively. While it was 38.5%, 69.8%, 26% and 12.5% in the 12, 1, 2 and 3 o'clock positions of the studied hips respectively using alpha angle >60°. The maximum alpha angle was more frequently prevalent at the 1 o'clock position in 71 (74%). Labral tear was detected in 26 (27.1%) hips and impingement test was positive in 12 (12.5%) hips. There was no correlation between the presence of cam-type morphology and range of motion of the hip, presence of positive impingement test nor labral tears.

Conclusions: Cam-type morphology prevalence is high among asymptomatic males, and mostly pronounced at the 1 o'clock position. A correlation between high alpha angle and positive impingement test or labral tear was not found in our cohort. Future studies are required to determine the natural history of asymptomatic cam-type morphology and risk of hip derangement.

Background: Persisting groin pain post total hip arthroplasty (THA) is a common and complex issue that can be difficult to diagnose and manage. Acetabular component positioning is often implicated.

Aims and methods: We used a previously well described and validated functional positioning protocol to determine if functional acetabular malpositioning was a factor in groin pain post THA and hence to determine if acetabular revision would be indicated. We compared patient-specific functional acetabular positioning to traditional CT evaluation of cup position and assessment of anterior cup overhang.

Results: 39 patients with groin pain post-THA were investigated. Functional acetabular malpositioning was diagnosed in 31% (12/39). Revision THA was performed in those 12 patients, resulting in resolution of functional malpositioning (100%), with an overall accuracy of 5.6° (range 1-12), and resolution of groin pain in 67% (8/12). 33% (4/12) of the revised implants had functional positioning located outside the traditional "40/20 zone". Comparison with CT indicated that 40% (4/10) of implants with anterior overhang were well positioned, however only 50% (6/12) of functionally malpositioned implants had CT evidence of anterior cup prominence. Of the 8/12 revision patients who had resolution of their groin pain, only 1 had cup prominence.

Conclusions: This study suggests that the utilisation of a patient specific functional positioning algorithm in the analysis of persistent groin pain following THA can assist in identifying the underlying cause of pain and help to guide treatment. For a functionally malpositioned acetabulum, revision surgery offers a potential resolution of groin pain.

Background: The choice between total hip arthroplasty (THA) and hemiarthroplasty (HA) to treat displaced femoral neck fractures, particularly among the elderly, is still controversial. Acetabular erosion consists of a late multifactorial process that may happen after hip HA resulting in significant postoperative burden. This study aims to investigate the impact of acetabular erosion progress after hip HA in patients over 70 years old.

Materials and methods: This is a 5-year (2013-2018) retrospective study including consecutive series of patients >70 years who were treated with bipolar hip HA for femoral neck fractures. Patients were categorised into 3 groups for analysis (A = 70-75 years, B = 75-80 years, C = >80 years). The study enrolled a total number of 813 patients who met the inclusion criteria. We assessed acetabular erosion through radiological examinations and measured functional deterioration using the modified Harris Hip Score (mHHS) at 6 and 12 months follow-up. Our comprehensive investigation extended over a maximum period of 5 years. The correlation of patients' characteristics and HA features on erosion progress was assessed.

Results: There were no significant differences in sex distribution, injury side, BMI, ASA score, bipolar head diameter, mHHS and leg-length discrepancy among the groups (p > 0.05). During the follow-up period, acetabular erosion with consequential conversion to THA was observed in 6.13%, 4.22% and 1.96% for Groups A, B and C respectively (p = 0.009). A statistically significant difference of acetabular erosion was observed in Group A compared to patients of Group C.

Conclusions: Age constitutes a significant factor of acetabular wear after HA in the elderly. The higher rate of acetabular wear in patients <75 years suggests that THA is a more viable option, as HA is for patients >80 years old.

Background: The management of the valgus-impacted neck of femur fracture (AO/OTA 31-B1) remains contentious. The objective of this study was to determine whether operative intervention is cost-effective.

Methods: We conducted a systematic review using electronic databases (Medline, Embase, Cochrane, Ebsco, Scholar) identifying studies published in the English language concerning valgus-impacted neck of femur fractures until June 2022. Additional studies were identified through hand searches of major orthopaedic journals, and bibliographies of major orthopaedic textbooks. MeSH terms (hip fracture and femoral neck fracture) and keywords (undisplaced, valgus-impacted, valgus, subcapital, Garden) connected by the Boolean operators "AND" and "OR" were used to identify studies. 2 reviewers independently extracted the data using standardised forms and recording spreadsheet. Methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-analysis of Statistics Assessment and Review Instrument. Meta-analysis was undertaken. Outcome measures were rate of displacement, avascular necrosis, non-union, mortality and requirement of further operative intervention. A cost utility analysis was then conducted to compare the 2 groups on the basis of the cost of initial treatment and the potential requirement of secondary intervention to hemiarthroplasty.

Results: 47 studies met the inclusion criteria. Meta-analysis data demonstrated a significant difference in the displacement rate of 22.8% and 2.8% between the nonoperative and internal fixation groups respectively (p = 0.05). The overall incidence of further operative intervention for each group was 23% and 10% respectively. There was no significant difference with respect to avascular necrosis, mortality or union rates. The cost utility analysis revealed nonoperative management to be approximately 60% more costly than initial internal fixation when the costs of subsequent surgery were included.

Conclusions: This meta-analysis of the existing literature concludes that whilst nonoperative management is possible for valgus impacted neck of femur fractures, it is associated with higher complication rates and greater expense than management by internal fixation.