HIP International

Multimodal analgesia regimes including local infiltration analgesia (LIA) have been successfully applied in fast-track hip arthroplasty programmes. LIA’s contribution to the analgesic effect in hip arthroplasty has been questioned. Our study sought to determine the analgesic efficacy of LIA in THA surgery in a fast-track programme.

Patients diagnosed with hip osteoarthritis scheduled for arthroplasty were randomised to receive LIA (120 ml ropivacaine 0.2% plus epinephrine 0.5 µ/ml) or saline as a part of a multimodal analgesia regime. The surgical team, the nursing staff, and patients were all blinded regarding patient allocation throughout the study. The primary outcome was pain assessed as a continuous variable using the visual analogue scale (VAS) at 4, 8, 24 and 48 hours postoperatively. Secondary outcomes included the amount of analgesic rescue consumption, complications and length of hospital stay.

A total of 63 patients were interviewed and agreed to participate in the study. No statistically significant differences were found between groups for pain measurements at 4, 8, 12, 24 and 48 hours after surgery. There were also no differences in rescue medication consumption, complications, or length of stay.

Our results suggest LIA (ropivacaine plus epinephrine, single shot) has no effect in pain management and has not shown benefits for early ambulation in primary THA surgery. Further research is needed to establish the optimal multimodal analgesia regime for THA fast-track programmes.

Clinicaltrials.gov (NCT03513276).

Diabetes mellitus (DM), poor glycaemic control and raised body mass index (BMI) have been associated with postoperative complications in arthroplasty, although the relative importance of these factors is unclear. We describe the prevalence of DM in elective hip arthroplasty in a UK centre, and evaluate the impact of these factors.

We analysed retrospective data for DM patients undergoing arthroplasty over a 6-year period and compared with non-diabetic matched controls (1 DM patient: 5 controls). DM was present in 5.7% of hip arthroplasty patients (82/1443).

Postoperative complications occurred in 12.2% of DM patients versus 12.9% of controls (p = 1.000); surgical complications were present in 6.1% of those with DM and 2.4% of controls (p = 0.087), while medical complications occurred in 8.5% of DM patients versus 10.7% of controls (p = 0.692). Complications developed in 23.1% of DM patients with poor glycaemic control (HbA1c > 53 mmol/mol) versus 9.8% with good control (p = 0.169). In DM patients and controls combined, complications occurred in 16.3% of obese patients versus 10.0% of non-obese patients (p = 0.043). In the DM cohort, 13.7% of overweight patients had complications versus 0% with a normal or low BMI (p = 0.587).

DM rates were lower than expected, and glycaemic control was good. Overall complication rates were unrelated to the presence of DM or to glycaemic control, although surgical complications were observed more frequently in those with DM and poor glycaemic control was uncommon within our cohort. Complications were more frequent in those with a higher BMI. Whether some patients with DM but without an increased risk of complications are currently being excluded from surgery requires exploration.

Cementless fixation is the standard for acetabular fixation in primary total hip arthroplasty (THA). There are various surface finishes thought to improve osteointegration, although literature regarding the long-term survival of some of these surfaces is limited. Regardless of design, primary stability is essential to allow for osteointegration. Previous studies have suggested an increased rate of radiolucency and compromised short-term functional outcomes using the Tritanium primary acetabular component (Stryker, Mahwah, NJ). The purpose of this study was to compare the primary Tritanium acetabular component to another contemporary acetabular component as a control group with an established clinical record.

444 consecutive, primary THAs performed by a single surgeon from 2008 to 2012 were reviewed. Patients were included if they had a minimum 1-year follow-up. Implant survivorship and modified Harris Hip Scores (mHHS) were recorded for all patients at final follow-up. Radiographs were evaluated by 2 surgeons at 6 weeks, 1 year, and the most recent follow-up for evidence of radiolucency and migration. Components were considered to have evidence of radiographic lucency if they had radiolucency in 2 or more DeLee zones.

198 patients met criteria for inclusion (96 Pinnacle, 102 Tritanium). Average follow-up was 28 (12–72) months. At final follow-up 6.2% of the Pinnacle cups and 29.4% of the Tritanium cups had radiographic evidence of loosening (p < 0.01). The average mHHS for the Tritanium group was 83.1, and 88.4 for the Pinnacle group (p < 0.01). Radiographic evidence of loosening also correlated with a lower mHHS: 75.5 versus 86.4 (p < 0.01). In patients that received Tritanium cups without screw fixation 44.6% showed radiographic evidence of loosening versus 8% that received screw fixation (p < 0.01). In total, 6 patients in the Tritanium group required revision for aseptic loosening of the acetabular component.

The 30% rate of radiographic loosening in the Tritanium group was significantly higher than the Pinnacle group and correlated with an inferior clinical outcome. Interestingly the use of screw augmentation was protective against radiographic evidence of loosening. This suggests that the Tritanium component may be prone to fibrous in-growth because of inadequate primary stability.

The prevalence of diabetes mellitus (DM) continues to increase among patients undergoing total hip arthroplasty (THA). It is unclear how insulin use is correlated with risk for adverse outcomes.

A cohort of 146,526 patients undergoing primary THA were identified in the 2005–2017 National Surgical Quality Improvement Program database. Patients were classified as insulin-dependent diabetic (IDDM), non-insulin-dependent diabetic (NIDDM), or not diabetic. Multivariate analyses were used.

Compared to patients without diabetes, patients with NIDDM were at increased risk for 4 of 17 perioperative adverse outcomes studied. Patients with IDDM were at increased risk for those 4 and 8 additional adverse outcomes (12 of the 17 studied).

These findings have important implications for preoperative risk stratification and quality improvement initiatives.

The uncemented total hip arthroplasty relies on a secure initial fixation of the femoral stem to achieve osseointegration. Undersizing of the femoral implant compromises this. Surgeons routinely review postoperative radiographs to assess appropriate sizing, but existing methods of assessment lack standardisation. We present a system of accurately and reliably classifying radiological undersizing, which will help us better understand the factors that might have led to undersizing.

To describe and evaluate a classification system for assessing radiological undersizing of the uncemented stem in hip arthroplasty.

We conducted a retrospective review of 1,337 consecutive hip arthroplasties using the Corail stem. Two independent investigators reviewed post-operative radiographs and classified them as either appropriately sized or undersized. Undersized stems were sub-categorised into four subtypes: uniformly undersized, varus undersized, valgus undersized or ‘cocktail-glass’ undersized. Inter- and intra-observer agreement was determined. The accuracy of our classification system was validated by comparison with digital re-templating. We further assessed patient demographics and stem size in relation to sizing.

1 in 5 cases (19.75%) were deemed radiologically undersized. The commonest subtypes of undersizing were uniformly (47%) and varus (39%) undersized. When assessing sizing and subtype categorisation, inter-observer agreement was 89–92% and intra-observer agreement 86%. Classification decisions showed 92% and 97% accuracy for uniformly undersizing and varus undersizing respectively when validated against digital re-templating. Age, gender and smaller stem size were significantly associated with radiological undersizing. The Corail KLA model (125° neck) was found to have a higher incidence of stems undersized in varus.

This study describes and validates a classification system for the analysis of radiological undersizing.

Excellent long-term survival has been reported for both the Taperloc and the Mallory-Head cementless stems. However, little is known about the migration behaviour of these stems which have different design rationales. The purpose of this randomised clinical trial was to compare the migration and clinical outcomes of these stems during 5 years of follow-up.

42 consecutive hips in 38 patients scheduled to receive cementless THA were randomised to either a Taperloc or a Mallory-Head stem. Evaluation took place preoperatively and postoperatively on the second day, at 6, 12, 26, and 52 weeks, and annually thereafter. Primary outcome was stem migration measured using roentgen stereophotogrammetric analysis (RSA) and secondary outcomes were the Harris Hip Score (HHS) and 36-Item Short-Form Health Survey (SF-36). No patients were lost to follow-up; in 1 patient the THA was removed due to deep infection 3 months postoperatively. In 6 hips migration measurements were not possible due to insufficient marker configuration.

Throughout the follow-up period of 5 years, 3-dimensional migration was comparable between the Taperloc and the Mallory-Head stems (p-values > 0.05). However, at the 5-year follow-up point the retroversion of the Mallory-Head stem was 0.9° more than the Taperloc stem (p = 0.04). Initial subsidence and retroversion were respectively as large as 6.8 mm and 3.6° for the Taperloc stem and 5 mm and 3.6° for the Mallory-Head stem. After the first postoperative year, both implants had stabilised. The mean increment of HHS, as well as the SF-36 scores during the 5-year follow-up, were comparable between the 2 stems.

The excellent long-term survival of both designs was confirmed in this study showing comparable initial migration with subsequent stabilisation. However, the Taperloc design with a flat, wedged geometry showed better rotational stability.

To investigate whether combined treatment of hyperbaric oxygen (HBO) and core decompression (CD) result with better outcomes and have an additional influence on health quality scores when compared with HBO alone.

63 consecutive patients’ 80 hips (43 male, 20 female, 17 bilateral), diagnosed with Stage II Osteonecrosis of the femoral head were included in our study. The mean age at presentation in the HBO and CD + HBO groups were 39.9 years and 39.2 years, respectively. The mean follow-up was 39.8 months (24–56 months) for HBO group and 43.1 months (24–58 months) for the CD + HBO group. Standard radiographs and MRI were performed initially and during controls. Clinical outcomes were assessed using the modified Harris Hip Score (HHS), the visual analogue score (VAS) and SF-36 life quality score.

52 hips (65%) were Ficat Stage IIa and 28 hips (35%) were IIb. Totally, 46 hips (30 hips IIa, 16 hips IIb) were in HBO alone group and 34 hips (22 hips IIa, 12 hips IIb) were in CD + HBO group. Both VAS and HHSs were improved in each group after treatment (p < 0.001). When both groups were compared, this improvement was more distinct and evident in CD + HBO combination group than HBO alone group (p < 0.001). The physical function and pain components of SF-36 survey were found to be different in between two groups (p < 0.005).

HBO treatment decreases pain, increases functional scores for Ficat Stage II patients. Addition of HBO treatment to decompression of the femoral head improves the results better than HBO alone. In particular, reduction of pain is more prevalent for Stage IIa patients than IIb with combination of HBO and CD therapies.

A critical part in preoperative planning for revision arthroplasty surgery involves the identification of the failed implant. Using a predictive artificial neural network (ANN) model, the objectives of this study were: (1) to develop a machine-learning algorithm using operative big data to identify an implant from a radiograph; and (2) to compare algorithms that optimise accuracy in a timely fashion.

Using 2116 postoperative anteroposterior (AP) hip radiographs of total hip arthroplasties from 2002 to 2019, 10 artificial neural networks were modeled and trained to classify the radiograph according to the femoral stem implanted. Stem brand and model was confirmed with 1594 operative reports. Model performance was determined by classification accuracy toward a random 706 AP hip radiographs, and again on a consecutive series of 324 radiographs prospectively collected over 2019.

The Dense-Net 201 architecture outperformed all others with 100.00% accuracy in training data, 95.15% accuracy on validation data, and 91.16% accuracy in the unique prospective series of patients. This outperformed all other models on the validation (p < 0.0001) and novel series (p < 0.0001). The convolutional neural network also displayed the probability (confidence) of the femoral stem classification for any input radiograph. This neural network averaged a runtime of 0.96 (SD 0.02) seconds for an iPhone 6 to calculate from a given radiograph when converted to an application.

Neural networks offer a useful adjunct to the surgeon in preoperative identification of the prior implant.

Despite the high success rate of total hip arthroplasty (THA), new implant technologies continue to be developed. Although potentially useful, such novel developments may result in unintended consequences, leading to revision surgery, often prematurely. In several instances, new technology that appeared promising was later found to be inferior to existing technology and resulting in early revision surgery. Additionally, technical surgical errors may also lead to early revisions. Some have argued that revisions related to such phenomena are potentially avoidable. The present analysis investigates to what extent the contribution of “failed new technology” and “technical errors” contributes to the revision burden and to the need for premature revision arthroplasty.

We retrospectively analysed 432 revision THAs and categorised them as either “late revisions” based on survivorship of 10 years or “premature revisions”. Among both cohorts, we determined what percentage of revisions were potentially avoidable and due to failed novel technologies and technical errors, and what percent were “unavoidable”.

Of the 432 revisions, 267 (62%) were considered premature and 38% were considered late. Of the premature revisions, 108 were considered potentially avoidable (81 failed novel technologies, 27 technical errors).

Our data demonstrates that new technology and surgical techniques can result in premature failure of THA. Surgeons should take caution when incorporating new implant technology or surgical techniques into their practice.

The aim of this prospective, randomised and controlled study was to evaluate the wear and fixation properties of a new cemented highly cross-linked all-polyethylene (HXLPE) cup in comparison with a conventional cemented ultra-high molecular weight polyethylene (ConvPE) cup using radiostereometric analysis (RSA).

A total of 58 patients (58 hips) with primary osteoarthritis (OA) were enrolled in a randomised controlled trial to receive either a ConvPE cup (control) or HXLPE cup (intervention) with identical geometry. The subjects were randomised in a 1:1 ratio. The primary endpoint was proximal wear measured as femoral head penetration into the cup, secondary outcomes were 3D-wear and annual proximal wear from 1 to 5 years. Cup fixation was measured as movement of the cup in relation to the acetabular bone with proximal migration being the primary outcome measure, 3D-migration and change in inclination as secondary outcomes. The patients were followed for 5 years with RSA performed postoperatively, at 3, 12, 24, and 60 months.

The HXLPE displayed a lower median proximal femoral head penetration compared to ConvPE, with a median difference at 2 years of –0.07 mm (95% CI, –0.10 to –0.04 mm), and –0.19 mm (95% CI, –0.27 to –0.15 mm) at 5 years. Annual proximal wear between 1 and 5 years was 0.03 mm/year for HXLPE and 0.06 mm/year for ConvPE (mean difference 0.05 mm, [95% CI, 0.03–0.07 mm]). Proximal migration, 3D migration and change in inclination was numerically slightly higher for HXLPE, albeit not statistically significant.

Compared to ConvPE, the HXLPE cup displayed significantly lower polyethylene wear. Cup migration was not statistically significant different.

NCT04322799.

Periacetabular osteotomy (PAO) is increasingly being used to treat young adults with symptomatic hip dysplasia. Currently there is a lack of evidence to guide return to driving after this procedure. This study aimed to identify the length of time required after a Periacetabular Osteotomy procedure before a patient can safely return to driving.

All patients undergoing PAO were assessed for suitability for the study. Inclusion criteria were: currently driving with a valid licence; and being able to attend follow-up assessment. Baseline driving reaction time was assessed using a driving simulator preoperatively. The simulation was repeated 5 times for each patient and reaction times recorded (Thinking time, Action time and Total reaction time for braking at 30 mph). The driving simulation was repeated using the same methods at 6 weeks and 12 weeks postoperatively. Pre- and postoperative times were compared.

26 patients were included (24 females, 2 males) with a mean age of 32 (range 19–50) years. The mean preoperative times were: Thinking time 0.48, Action time 0.21, Total time 0.69 seconds. At 6 weeks postoperatively, mean Action time increased to 0.26 seconds (p = 0.012) and mean Total time increased to 0.78 seconds (p = 0.013). By 12 weeks post procedure, there was no significant difference in reaction times compared to baseline (mean Thinking time 0.47 seconds, Action time 0.23, Total time 0.72; p > 0.05).

Most patients may not be safe to drive at 6 weeks following PAO procedures but should be safe to drive at 12 weeks postoperatively. Individual patient factors should also be taken into consideration.

It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment.

In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography.

10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases.

All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV).

Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

Residual acetabular dysplasia of the hip after open reduction can complicate the treatment of developmental dysplasia of the hip (DDH) due to the potential need for corrective surgery. This retrospective study aimed to determine the predictive factors for acetabular development using postoperative radiographs and magnetic resonance imaging (MRI).

We retrospectively investigated 74 hips of patients with DDH who underwent open reduction after reaching walking age and were followed up radiologically until skeletal maturity. We evaluated the cartilaginous acetabulum and labrum using a new method that measures the cartilaginous and labral landmarks on coronal and axial MR T2*-weighted images in patients aged 5 years. The mean age at the time of surgery was 22 months and that at the final survey was 20 years. Severin classification was determined at the final follow-up. Groups with good (53 hips) and poor (21 hips) outcomes were compared using the postoperative radiographic and MRI parameters recorded at 5 years of age. Factors predicting acetabular development were identified using univariate and multiple logistic analyses.

There were no significant differences in the bony-acetabular index (AI) and centre-edge (CE) angle between the good and poor outcome groups. However, the poor outcome group had significantly larger cartilaginous- and labral-AIs but significantly smaller cartilaginous- and labral-CE angles than the good outcome group (both p < 0.05). Multiple logistic regression analysis showed that labral-AI and labral-CE angle were predictors of acetabular development after open reduction for DDH, and their optimal cut-offs were 4° (77% sensitivity, 76% specificity) and 37° (68% sensitivity, 85% specificity), respectively.

Normal cartilaginous acetabulum development occurs in childhood, and evaluation using only radiographs is difficult. However, labral-AI ⩾4° and labral-CE angle <37° on MRI at 5 years of age offer useful indications for corrective surgery in patients with DDH.

The Chiari pelvic osteotomy (CPO) has been recommended as a salvage procedure to improve head coverage in case of hip joint incongruence in paediatric hip disease. In this study, we aimed to assess the long-term results of CPO for severe Legg-Calvé-Perthes disease (LCPD).

A total of 39 patients who underwent a CPO at our department between 1995 and 2010 were prospectively followed both radiologically (Stulberg classification) and clinically (Harris Hip Score [HHS], conversion into total hip arthroplasty). In this study, we retrospectively reviewed the cases of 12 hips (12 patients, 3 girls, 8 left hips) treated by CPO for severe LCPD (Catterall grade 3 or 4) with hip joint incongruence. Mean follow-up was 14.0 (range 7.6–21.3) years.

Mean age at surgery was 10.2 (range 8.2–17.8) years. Additional femoral osteotomy was performed in 8 patients. A good radiological result (Stulberg I or II) was achieved in 2 patients, a fair result (Stulberg III) in 4 patients, and a poor outcome (Stulberg IV or V) in 6 patients. Mean postoperative HHS averaged 93 (range 65–100) points. An excellent functional outcome (HHS 90–100 points) was achieved in 9 patients. No patient underwent total hip arthroplasty during follow-up. Postoperative limb-length discrepancy was found in 3 patients.

CPO for severe LCPD with hip joint incongruence resulted in good long-term clinical outcome in about ⅔ of our patients after a mean of 14 years. Our results suggest that CPO can still be considered as a salvage joint-conserving procedure in this selected group of younger patients.

The modified Dunn procedure (MDP) has risen enthusiasm in treating slipped capital femoral epiphyses (SCFE) due to the anatomic reduction and high patients’ satisfaction rates at long-term follow-up. Main aim of this study is to compare clinical and radiographic outcomes of 2 cohorts with moderate to severe stable SCFE treated by MDP and in situ fixation.

Medical records were analysed to collect demographic data, comorbidities and time from slip to surgery. The collected postoperative data were: avascular necrosis (AVN); complications; progression of osteoarthritis and subsequent procedures. Southwick angles (SA), alpha angles and Klein line were measured on the preoperative x-rays, on the immediate postoperative period and at the latest follow-up. Outcomes scores were recorded by the following questionnaires: the Harris Hip Score, the Hip disability and Osteoarthritis Outcome Score, the Merle d’Aubigné and Postel score and the Western Ontario and McMaster Universities Arthritis Index. Kaplan-Meier survivorship curve was calculated.

We compared 81 hips treated by MDP with 22 hips treated by in situ pinning (PS) for moderate/severe stable SCFE. No significant differences were found between the 2 groups in terms of age, BMI, comorbidities and preoperative slip angles. At the latest follow-up, postoperative anteroposterior mean slip angles were respectively 6.2 and 19.9° in MDP and PS group (p = 0.3). Slip angles in frog lateral view were 11° in the MDP group and 39.7° in the PS group (p = 0.2). MDP group achieved better correction angles on frog leg view (11° vs. 39.7°; p < 0.001). There was no statistically significant difference in the occurrence of AVN among both groups (19.7% MDP group vs. 31.8% PS group) (p = 0.2).

The MDP in treating severe stable SCFE showed the best deformities corrections in conjunction with the highest functional scores at long-term follow-up and similar rates of osteonecrosis compared to in situ fixation.

Proximal femoral fracture is common with a high mortality (7% mortality at 30 days). Accurate determination of mortality risk allows better consenting, clinical management and expectation management. Our study aim was to develop a prognostic tool to predict 30-day mortality after proximal femoral fracture, among patients treated within a dedicated hip fracture unit.

We collected data from our hospital concerning 2210 patients with 2287 proximal femoral fractures. The clinical parameters of 97 patients who died within 30 days of surgery were analysed. We used logistic regression to determine if the parameters’ relationship with 30-day mortality was statistically significant or not. The statistically significant parameters were used to create a prognostic model for predicting 30-day mortality.

The 5 independent predictors of 30-day mortality were gender, age, admission source, preoperative Abbreviated Mental Test Score (AMTS) and American Society of Anesthesiologists Score (ASA). The highest risk was for males >85 years, admitted from institutional care, with low preoperative mental test score and high ASA grade. Using these predictors, we formulated the G4A score. The Hosmer-Lemeshow ‘goodness of fit’ test showed good concordance between observed and predicted mortality rates.

We recommend the use of the G4A score to predict 30-day mortality after surgery for proximal femoral fracture, particularly within dedicated hip fracture units. Further research is needed to establish whether the findings of this study are applicable on a national scale.