HIP International最新文献

Purpose: To determine whether synthetic grafts are a satisfactory treatment option for pathological proximal femoral fractures in children.

Methods: Paediatric patients treated for pathological fractures of the proximal femur between 2013 and 2020 were evaluated retrospectively. 17 patients with a mean age of 10.7 years (range 6-16 years) were assessed. The definitive histopathological diagnoses were SBC (simple bone cyst) (12) and ABC (aneurysmal bone cyst) (5). The median duration of follow-up was 37 months (range 12-70 months).

Results: All patients returned to their normal daily routine within 3-8 months following surgery. The mean post-op recovery time was 3.2 months (range 3-6 months). Graft was incorporated at approximately 12 months. No significant radiographic healing was observed in 2 patients. In the remaining 15 patients, the mean duration of healing was 14 months (range 8-24 months).

Conclusion: Synthetic grafts are a satisfactory treatment option for pathological proximal femoral fractures in children.

Aim: Preoperative identification of acetabular corrections that optimally improve joint stability and reduce elevated contact stresses could further reduce osteoarthritis progression in patients with hip dysplasia who are treated with periacetabular osteotomy (PAO). The purpose of this study was to investigate how providing patient-specific, mechanically optimal acetabular reorientations to the surgeon during preoperative planning affected the surgically achieved correction.

Methods: Preoperative CT scans were used to create patient-specific hip models for 6 patients scheduled for PAO. A simulated acetabular fragment was extracted from the preoperative pelvis model and computationally rotated to simulate candidate acetabular reorientations. For each candidate, discrete element analysis was used to compute contact stresses during walking, which were summed over the gait cycle and scaled by patient age to obtain chronic contact stress-time exposure. The ideal patient-specific reorientation was identified using a cost function that balances minimising chronic stress exposures and achieving surgically acceptable acetabular coverage angles. The optimal reorientation angles and associated contact mechanics were provided to the surgeon preoperatively. After PAO was performed, a model of the surgically achieved correction was created from a postoperative CT scan. Radiographic coverage and contact mechanics were compared between preoperative, optimal, and surgically achieved orientations.

Results: While surgically achieved reorientations were not significantly different from optimal reorientations in radiographically measured lateral (p = 0.094) or anterior (p = 0.063) coverage, surgically achieved reorientations had significantly (p = 0.031) reduced total contact area compared to optimal reorientations. The difference in lateral coverage and peak chronic exposure between surgically achieved and optimal reorientations decreased with increasing surgeon experience using the models (R² = 0.758, R² = 0.630, respectively).

Conclusions: Providing hip surgeons with a patient-specific, computationally optimal reorientation during preoperative planning may improve contact mechanics after PAO, which may help reduce osteoarthritis progression in patients with hip dysplasia.

Background: Modular femoral stems have the advantage of anatomic hip reconstruction by restoring the femoral offset thus minimising the bearing surface wear, implant loosening and dislocation.

Aim: This study aims to investigate the existing literature on modular neck fractures, to identify predisposing factors and guide the decision-making process in the management of these difficult cases.

Methods: A systematic literature review was conducted until July 2022. PRISMA guidelines were followed, eligibility criteria were set, and methodology assessment of included studies was conducted based on MINORS criteria, size and primary outcome. Data were extracted and analysed thoroughly.

Results: 5657 studies were initially screened; the full texts of 124 records were assessed and finally, 32 reports were included. There were 7 clinical studies and 25 case reports. A total of 4825 patients (5204 hips) with a mean age 62.38 years and a mean BMI 29.06 kg/m² were analysed in the 7 clinical studies. The reported overall weighted revision rate was 0.86%, while the weighted mean modular neck fracture rate was 0.26%. The usual history was sudden experience of hip pain and instability. The average time interval to neck fracture was 4.57 (range 3-4.7) years and a long modular neck was identified in 91.17% of them. Data from case reports showed a mean age and average BMI of 55.85 and 31.63 kg/m². 82.35% of the patients were male. Necks were fractured after an average time interval of 64.5 ± 8.8 months.

Conclusions: The incidence of modular neck fracture is significant. The profile of a male, obese patient with a long modular neck increased risk of neck fracture. Microstructural investigation of the retrieved implants demonstrated a higher incidence of fracture line in the base of the neck junction and at its anterolateral distal part. Surgeons should be aware of this complication while using or revising such protheses.

Background: Corrosion at the head-neck junction of femoral stems is a rare complication of total hip arthroplasty (THA) with manifestations ranging from subclinical wear to failure. Prior studies have identified a single femoral component design with an increased propensity for catastrophic trunnion failure. The purpose of the present study was to quantify trunnion damage of this femoral component retrieved from patients undergoing revision THA for non-trunnionosis indications.

Methods: 24 femoral components from a single manufacturer were identified for study inclusion. Each prosthesis underwent stereomicroscopic inspection. Corrosion and fretting scores were assigned per the Goldberg criteria to quadrants of the trunnion. Material loss was calculated based on cone angles across trunnion quadrants. This was carried out using a coordinate measuring machine that digitised each trunnion surface. Stems were compared to a series of femoral stems with the same trunnion design.

Results: 20 of the 24 (83%) trunnions demonstrated corrosion, all 24 trunnions demonstrated fretting. Corrosion scores did not statistically differ with respect to trunnion zone (p = 0.53), while fretting scores were higher in the inferior compared to the superior zones (p < 0.001). There was no significant difference in cone angles assessing material loss between stems (p = 0.25).

Conclusions: Evidence of trunnion damage was observed in each stem retrieved for non-trunnionosis revision. Fretting occurred more frequently about the inferior quadrants. However, digitised trunnion shapes were similar between compared stems exhibiting no material loss. Therefore, it is possible that previous reports of trunnion failures for this implant are not a systemic issue, and that further investigation is required.

Introduction: This study aims to: (1) describe perioperative complications amongst patients who underwent primary total hip arthroplasty (THA) using a short cementless, titanium, flat, tapered stem; (2) estimate this stem's early- to mid-term survival; (3) identify factors associated with revision arthroplasty; and (4) describe femoral remodelling at minimum 6 years postoperatively.

Methods: A retrospective review of consecutive patients who underwent THA using a Taperloc Microplasty stem (Zimmer-Biomet, Warsaw, Indiana, USA) with minimum 2-year follow-up was performed. Surgeries were performed by 1 of 6, non-designer, arthroplasty surgeons between 2014 and 2018. Outcomes included perioperative complications including revision arthroplasty, and survival. Cox analysis was used to analyse the effect of different factors on risk of revision arthroplasty. Radiographs with 6-year follow-up served to describe femoral remodelling.

Results: In 1205 patients, followed for 5.1 ± 1.4 years, the incidence of perioperative complication was 5.2% for which 29 patients (2.4%) required revision arthroplasty. The 5- and 7-year survival rates were 97.8% (95% CI, 96.9-98.5) and 97.0% (95% CI, 95.6-98.0), respectively. The only factor associated with revision arthroplasty was proximal femur morphology, as per Dorr classification (HR 1.24 [95%CI, 1.09-1.41]; p = 0.005). During radiographic assessment, 12% of patients showed ⩾25% of relative change in cortical thickness in Gruen zones 3 or 5. We observed calcar remodelling in 50% of radiographs while 10% showed presence of a pedestal sign.

Conclusions: The 7-year survivorship of the Taperloc Microplasty stem is within National Institute for Health and Care Excellence (NICE) guidelines. Patients ⩽65 years with osteoarthritis and Dorr A/B femoral morphology may be ideal candidates for THA with this stem. Femoral remodelling is common and not associated with adverse outcome.

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.