Advertisement for orthosearch.org.uk
Results 1 - 20 of 39
Results per page:
Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_11 | Pages 42 - 42
1 Nov 2022
Kumar K Van Damme F Audenaert E Khanduja V Malviya A
Full Access

Abstract. Introduction. Recurrent groin pain following periacetabular osteotomy (PAO) is a challenging problem. The purpose of our study was to evaluate the position and dynamics of the psoas tendon as a potential cause for recurrent groin pain following PAO. Methods. Patients with recurrent groin pain following PAO were identified from a single surgeon series. A total of 13 patients with 18 hips (4.7%) out of a 386 PAO, had recurrent groin pain. Muscle path of the psoas tendon was accurately represented using 3D models from CT data were created with Mimics software. A validated discrete element model using rigid body springs was used to predict psoas tendon movement during hip circumduction and walking. Results. Five out of the 18 hips did not show any malformations at the osteotomy site. Thirteen hips (72%) showed malformation secondary to callus at the superior pubic ramus. These were classified into: osteophytes at the osteotomy site, hypertrophic callus or non-union and malunion at the osteotomy. Mean minimal distance of the psoas tendon to osteophytes was found to be 6.24 mm (n=6) and to the osteotomy site was 14.18 mm (n=18). Conclusions. Recurrent groin pain after PAO needs a thorough assessment. One need to have a high suspicion of psoas issues as a cause. 3D CT scan may be necessary to identify causes related to healing of the pubic osteotomy. Dynamic ultrasound of the psoas psoas tendon may help in evaluating for psoas impingement as a cause of recurrent groin pain in these cases


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_12 | Pages 25 - 25
1 Dec 2022
Verhaegen J Vandeputte F Van den Broecke R Roose S Driesen R Corten K
Full Access

Psoas tendinopathy is a potential cause of groin pain after primary total hip arthroplasty (THA). The direct anterior approach (DAA) is becoming increasingly popular as the standard approach for primary THA due to being a muscle preserving technique. It is unclear what the prevalence is for the development of psoas-related pain after DAA THA, how this can influence patient reported outcome, and which risk factors can be identified. This retrospective case control study of prospectively recorded data evaluated 1784 patients who underwent 2087 primary DAA THA procedures between January 2017 and September 2019. Psoas tendinopathy was defined as (1) persistence of groin pain after DAA THA and was triggered by active hip flexion, (2) exclusion of other causes such as dislocation, infection, implant loosening or (occult) fractures, and (3) a positive response to an image-guided injection with xylocaine and steroid into the psoas tendon sheath. Complication-, re-operation rates, and patient-reported outcome measures (PROMs) were measured. Forty-three patients (45 hips; 2.2%) were diagnosed with psoas tendinopathy according to the above-described criteria. The mean age of patients who developed psoas tendinopathy was 50.8±11.7 years, which was significantly lower than the mean age of patients without psoas pain (62.4±12.7y; p<0.001). Patients with primary hip osteoarthritis were significantly less likely to develop psoas tendinopathy (14/1207; 1.2%) in comparison to patients with secondary hip osteoarthritis to dysplasia (18/501; 3.6%) (p<0.001) or FAI (12/305; 3.9%) (p<0.001). Patients with psoas tendinopathy had significantly lower PROM scores at 6 weeks and 1 year follow-up. Psoas tendinopathy was present in 2.2% after DAA THA. Younger age and secondary osteoarthritis due to dysplasia or FAI were risk factors for the development of psoas tendinopathy. Post-operatively, patients with psoas tendinopathy often also presented with low back pain and lateral trochanteric pain. Psoas tendinopathy had an important influence on the evolution of PROM scores


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 42 - 42
23 Feb 2023
Bekhit P Ou C Baker J
Full Access

Sarcopenia has been observed to be a predictor of mortality in international studies of patients with metastatic disease of the spine. This study aimed to validate sarcopenia as a prognostic tool in a New Zealand setting. A secondary aim of this study was to assess the intra-observer reliability of measurements of psoas and vertebral body cross sectional areas on computed tomography imaging. A cohort of patients who had presented to Waikato Hospital with secondary neoplasia in the spinal column from 2014 to 2018 was selected. Cross sectional psoas and vertebral body areas were measured at the mid-pedicle L3 level, followed by calculation of the psoas to vertebral body cross sectional area ratio. Psoas to vertebral body cross sectional area ratio was compared with survivorship. The strength of the correlation between sarcopenia and survivorship was compared with the correlation between serum albumin and survivorship, as well as the correlation between the Metastatic Spine Risk Index (MSRI) and survivorship. A total of 110 patients who received operative (34) and non-operative (76) were included. The results demonstrate that psoas to vertebral body cross sectional area ratio is not statistically significantly correlated with survivorship (p=0.53). Serum albumin is significantly correlated with survivorship (p<0.0001), as was the MSRI. There is good intra-observer and inter-observer reliability for measurements of psoas to vertebral body cross sectional area. This study failed to demonstrate the utility for the psoas to vertebral body cross sectional area ratio that other studies have demonstrated in estimating survivorship. Serum albumin levels remain a useful prognostic indicator in patients with secondary tumours in the vertebral column


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_7 | Pages 30 - 30
1 Jul 2020
Faizan A Zhang J Scholl L
Full Access

Iliopsoas tendonitis after total hip arthroplasty (THA) can be a considerable cause of pain and patient dissatisfaction. The optimal cup position to avoid iliopsoas tendonitis has not been clearly established. Implant designs have also been developed with an anterior recess to avoid iliopsoas impingement. The purpose of this cadaveric study was to determine the effect of cup position and implant design on iliopsoas impingement. Bilateral THA was performed on three fresh frozen cadavers using oversized (jumbo) offset head center revision acetabular cups with an anterior recess (60, 62 and 66 mm diameter) and tapered wedge primary stems through a posterior approach. A 2mm diameter flexible stainless steel cable was inserted into the psoas tendon sheath between the muscle and the surrounding membrane to identify the location of the psoas muscle radiographically. CT scans of each cadaver were imported in an imaging software. The acetabular shells, cables as well as pelvis were segmented to create separate solid models of each. The offset head center shell was virtually replaced with an equivalent diameter hemispherical shell by overlaying the outer shell surfaces of both designs and keeping the faces of shells parallel. The shortest distance between each shell and cable was measured. To determine the influence of cup inclination and anteversion on psoas impingement, we virtually varied the inclination (30°/40°/50°) and anteversion (10°/20°/30°) angles for both shell designs. The CT analysis revealed that the original orientation (inclination/anteversion) of the shells implanted in 3 cadavers were as follows: Left1: 44.7°/23.3°, Right1: 41.7°/33.8°, Left2: 40/17, Right2: 31.7/23.5, Left3: 33/2908, Right3: 46.7/6.3. For the offset center shells, the shell to cable distance in all the above cases were positive indicating that there was clearance between the shells and psoas. For the hemispherical shells, in 3 out of 6 cases, the distance was negative indicating impingement of psoas. With the virtual implantation of both shell designs at orientations 40°/10°, 40°/20°, 40°/30° we found that greater anteversion helped decrease psoas impingement in both shell designs. When we analyzed the influence of inclination angle on psoas impingement by comparing wire distances for three orientations (30°/20°, 40°/20°, 50°/20°), we found that the effect was less pronounced. Further analysis comparing the offset head center shell to the conventional hemispherical shell revealed that the offset design was favored (greater clearance between the shell and the wire) in 17 out of 18 cases when the effect of anteversion was considered and in 15 out of 18 cases when the effect of inclinations was considered. Our results indicate that psoas impingement is related to both cup position and implant geometry. For an oversized jumbo cup, psoas impingement is reduced by greater anteversion while cup inclination has little effect. An offset head center cup with an anterior recess was effective in reducing psoas impingement in comparison to a conventional hemispherical geometry. In conclusion, adequate anteversion is important to avoid psoas impingement with jumbo acetabular shells and an implant with an anterior recess may further mitigate the risk of psoas impingement


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 51 - 51
23 Feb 2023
Full Access

Dual mobility is a French concept that appeared in the 1970s and was initially intended to reduce dislocation rates. In recent years, this concept has evolved with new HA titanium spray coatings, new external macrostructures, and better-quality polyethylene. This has allowed to extend the indications to younger and therefore active populations. The objective of our work is to analyze at least 10 years a homogeneous and continuous series of 170 primary total hip replacements associating a latest generation Novae Sunfit. ®. dual mobility cup with a straight femoral stem. Only primary arthroplasties for osteoarthritis or necrosis were included. Total hip arthroplasty was always performed through a posterolateral approach. All patients had regular clinical and radiological follow-up. The average follow-up in our series was 11.5 years. The average age of the population is 71 years. At the last follow-up, there were 17 deaths, 6 losses to follow up and 9 adverse events, including 1 cup change for psoas impingement and 1 dislocation. The low rate of dislocation at 11 years confirms the high stability of the dual mobility, which should be recommended for primary procedure for patients at high risk of postoperative instability. The lack of intraprosthetic dislocation due to wear at 11 years of follow-up highlights the good quality of the latest generation of polyethylene, and the need to combine high-polished surfaces and a refined femoral neck with a dual mobility cup. Finally, the lack of aseptic loosening confirms the quality of the secondary fixation of these implants and justifies their wider use in all patients


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_16 | Pages 125 - 125
1 Dec 2015
Menon A Agashe V Jakkan M
Full Access

The insidious and occult characteristics of psoas abscess and clinical features similar to conditions like lumbar strain, abdominal/urologic disorders sometimes cause diagnostic delays; resulting in considerably high morbidity and mortality. Chronic inflammatory conditions of the digestive tract and tuberculosis of spine are the commonest source of secondary abscess in the developed and developing countries, respectively [1]. We report a case of an 86 year with a psoas abscess secondary to mucinous adenocarcinoma of colon. 86 year old female presented with right thigh pain in February 2014. CT scan confirmed the clinical suspicion of right psoas abscess which was drained surgically. Intraoperatively, we found pus mixed with mucinous material coming from a small opening in a rounded structure lateral to psoas which could not be identified. The abscess recurred within 2 days. Culture grew Pseudomonas aerugenosa and streptococcus viridans and histopathology showed metastatsis of mucin secreting adenocarcinoma infiltrating the muscle with pyogenic abscess. Repeat CT scan showed abscess communicating with tumor in the colon(Fig 1). Abscess was drained, but tumor was not addressed considering patients age. The infection resolved with 6 weeks of oral linezolid, however the patient expired after 8 months. Cultures in secondary psoas abscess are often mixed, with E. coli and Bacteroides spp predominating. One must rule out gastrointestinal/genitourinary pathology in cases where the CT/ USG guided culture reports are suggestive of gram negative infection. The fact that carcinoma of the colon could be a cause of psoas abscess should be considered when an unexplained psoas abscess is diagnosed [2]. Acknowledgements. None of the authors received payments or services, either directly or indirectly from a third party in support of any aspect of this work that could be perceived to influence what is written


Abstract. Optimal acetabular component position in Total Hip Arthroplasty is vital for avoiding complications such as dislocation and impingement, Transverse acetabular ligament (TAL) have been shown to be a reliable landmark to guide optimum acetabular cup position. Reports of iliopsoas impingement caused by acetabular components exist. The Psoas fossa (PF) is not a well-regarded landmark for Component positioning. Our aim was to assess the relationship of the TAL and PF in relation to Acetabular Component positioning. A total of 22 cadavers were implanted on 4 occasions with the an uncemented acetabular component. Measurements were taken between the inner edge of TAL and the base of the acetabular component and the distance between the lower end of the PF and the most medial end of TAL. The distance between the edge of the acetabular component and TAL was a mean of 1.6cm (range 1.4–18cm). The distance between the medial end of TAL and the lowest part of PF was a mean of 1.cm (range 1,3–1.8cm) It was evident that the edge of PF was not aligned with TAL. Optimal acetabular component position is vital to the longevity and outcome following THA. TAL provides a landmark to guide acetabular component position. However we feel the PF is a better landmark to allow appropriate positioning of the acetabular component inside edge of the acetabulum inside the bone without exposure of the component rim and thus preventing iliopsoas impingement at the psoas notch and resultant groin pain


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 122 - 122
1 May 2016
Patel R Zumbrunn T Varadarajan K Freiberg A Rubash H Muratoglu O Malchau H
Full Access

Introduction. Dual-mobility (DM) liners have increased popularity due to the range of motion and stability provided by these implants. However, larger head diameters have been associated with anterior hip pain, due to surrounding soft-tissue impingement, particularly the iliopsoas. To address this, an anatomically contoured dual mobility (ACDM) liner was designed by reducing the volume of the liner below the equator (Fig1). Previous cadaver studies have shown that the ACDM significantly reduces iliopsoas tenting and trapping of the liner compared to conventional designs. We created a finite element study based on previous cadaver testing to further analyze the effectiveness of the ACDM design in reducing soft-tissue impingement, specifically the tendon-liner contact pressure and the tendon stress. Methods. The finite element model was developed within COMSOL 4.3b. The psoas tendon was modelled as a Yeoh hyper-elastic Material, which uses 3 constants (c1-c3), density (1.73g/cm3) and a bulk modulus (26GPa)[Hirokawa,2000]. In a previous, separate study, the average stiffness of 10 psoas tendon samples (5 cadavers), were measured to be 339[N/mm] in the linear region with average width and thickness of 14mmX4mm. The 3 constants were tuned to match experimental uniaxial test data, and were 5[GPa], 0[Gpa], and 46[GPa] for c1, c2, and c3 respectively. The implant components were rigidly modeled relative to the psoas. Cadaver specific CT models were used to create the FEA geometry. The insertion points for the Psoas were digitally determined on the proximal end of the lesser trochanter, and the psoas notch on the pelvis for hip flexion angles of −15°, 0°, 15° and 30°. These insertion points determined the length of the psoas and its relative position to the femoral head in 3D. The specific liner size and position for each cadaver was determined by implant planning with the CT models. In this abstract, we only present data for 2 specimens (left/right hips) with 44mm conventional DM, and 44mm ACDM, matching specimen anatomy. A 500N tensile load was applied to the psoas tendon proximally to simulate moderate physiological loading, the average/max stresses and contact pressures between the psoas and the two liner designs were determined. Results. At all flexion angles from −15° to 30°, the ACDM had lower psoas-liner contact pressure and stress compared to the conventional liner. Both contact pressure and tendon stress decreased for both liners with increasing hip flexion. At −15° flexion angle, there was an average contact pressure difference of .51MPa between the conventional and ACDM designs, or 37% decrease in pressure when using the ACDM. The average difference in tendon stress was 67.9MPa, or a 59% decrease in stress when using the ACDM (fig2, fig3). Conclusion. This study utilized cadaver specific FEA models to evaluate interaction between the iliopsoas tendon and conventional and ACDM liners. Although this abstract presented FEA models for only four hips (two specimens), the results show a notable reduction in contact pressure and tendon stress with ACDM designs. This validates findings from previous cadaver studies, suggesting that anatomically contoured designs could reduce anterior hip pain and soft tissue impingement


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 12 - 12
23 Feb 2023
Hardwick-Morris M Twiggs J Miles B Balakumar J Walter WL
Full Access

Iliopsoas impingement occurs in between 5–30% of patients after hip arthroplasty and has been thought to only be caused by an oversized cup, cup malpositioning, or the depth of the psoas valley. However, no study has associated the relationship between preoperative measurements with the risk of impingement. This study sought to assess impingement between the iliopsoas and acetabular cup using a novel validated model to determine the risk factors for iliopsoas impingement. 413 patients received lower limb CT scans and lateral x-rays that were segmented, landmarked, and measured using a validated preoperative planning protocol. Implants were positioned according to the preference of ten experienced surgeons. The segmented bones were transformed to the standing reference frame and simulated with a novel computational model that detects impingement between the iliopsoas and acetabular cup. Definitions of patients at-risk and not at-risk of impingement were defined from a previous validation study of the simulation. At-risk patients were propensity score matched to not at-risk patients. 21% of patients were assessed as being at-risk of iliopsoas impingement. Significant differences between at-risk patients and not at-risk patients were observed in standing pelvic tilt (p << 0.01), standing femoral internal rotation (p << 0.01), medio-lateral centre-of-rotation (COR) change (p << 0.01), supine cup anteversion (p << 0.01), pre- to postoperative cup offset change (p << 0.001), postoperative gross offset (p = 0.009), and supero-inferior COR change (p = 0.02). Impingement between the iliopsoas and acetabular cup is under-studied and may be more common than is published in the literature. Previously it has been thought to only be related to cup size or positioning. However, we have observed significant differences between at-risk and not at-risk patients in additional measurements. This indicates that its occurrence is more complex than simply being related to cup position


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_13 | Pages 52 - 52
1 Dec 2022
Moskven E Lasry O Singh S Flexman A Fisher C Street J Boyd M Ailon T Dvorak M Kwon B Paquette S Dea N Charest-Morin R
Full Access

En bloc resection for primary bone tumours and isolated metastasis are complex surgeries associated with a high rate of adverse events (AEs). The primary objective of this study was to explore the relationship between frailty/sarcopenia and major perioperative AEs following en bloc resection for primary bone tumours or isolated metastases of the spine. Secondary objectives were to report the prevalence and distribution of frailty and sarcopenia, and determine the relationship between these factors and length of stay (LOS), unplanned reoperation, and 1-year postoperative mortality in this population. This is a retrospective study of prospectively collected data from a single quaternary care referral center consisting of patients undergoing an elective en bloc resection for a primary bone tumour or an isolated spinal metastasis between January 1st, 2009 and February 28th, 2020. Frailty was calculated with the modified frailty index (mFI) and spine tumour frailty index (STFI). Sarcopenia, determined by the total psoas area (TPA) vertebral body (VB) ratio (TPA/VB), was measured at L3 and L4. Regression analysis produced ORs, IRRs, and HRs that quantified the association between frailty/sarcopenia and major perioperative AEs, LOS, unplanned reoperation and 1-year postoperative mortality. One hundred twelve patients met the inclusion criteria. Using the mFI, five patients (5%) were frail (mFI ³ 0.21), while the STFI identified 21 patients (19%) as frail (STFI ³ 2). The mean CT ratios were 1.45 (SD 0.05) and 1.81 (SD 0.06) at L3 and L4 respectively. Unadjusted analysis demonstrated that sarcopenia and frailty were not significant predictors of major perioperative AEs, LOS or unplanned reoperation. Sarcopenia defined by the CT L3 TPA/VB and CT L4 TPA/VB ratios significantly predicted 1-year mortality (HR of 0.32 per one unit increase, 95% CI 0.11-0.93, p=0.04 vs. HR of 0.28 per one unit increase, 95% CI 0.11-0.69, p=0.01) following unadjusted analysis. Frailty defined by an STFI score ≥ 2 predicted 1-year postoperative mortality (OR of 2.10, 95% CI 1.02-4.30, p=0.04). The mFI was not predictive of any clinical outcome in patients undergoing en bloc resection for primary bone tumours or isolated metastases of the spine. Sarcopenia defined by the CT L3 TPA/VB and L4 TPA/VB and frailty assessed with the STFI predicted 1-year postoperative mortality on univariate analysis but not major perioperative AEs, LOS or reoperation. Further investigation with a larger cohort is needed to identify the optimal measure for assessing frailty and sarcopenia in this spine population


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_4 | Pages 130 - 130
1 Apr 2019
Tamura K Takao M Hamada H Sakai T Sugano N
Full Access

Introduction. Most of patients with unilateral hip disease shows muscle volume atrophy of pelvis and thigh in the affected side because of pain and disuse, resulting in reduced muscle weakness and limping. However, it is unclear how the muscle atrophy correlated with muscle strength in the patient with hip disorders. A previous study have demonstrated that the volume of the gluteus medius correlated with the muscle strength by volumetric measurement using 3 dimensional computed tomography (3D-CT) data, however, muscles influence each other during motions and there is no reports focusing on the relationship between some major muscles of pelvis and thigh including gluteus maximus, gluteus medius, iliopsoas and quadriceps and muscle strength in several hip and knee motions. Therefore, the purpose of the present study is to evaluate the relationship between muscle volumetric atrophy of major muscles of pelvis and thigh and muscle strength in flexion, extension and abduction of hip joints and extension of knee joint before surgery in patients with unilateral hip disease. Material and Methods. The subjects were 38 patients with unilateral hip osteoarthritis, who underwent hip joint surgery. They all underwent preoperative computed tomography (CT) for preoperative planning. There were 6 males and 32 females with average age 59.5 years old. Before surgery, isometric muscle strength in hip flexion, hip extension, hip abduction and knee extension were measured using a hand held dynamometer (µTas F-1, ANIMA Japan). Major muscles including gluteus maximus, gluteus medius, iliopsoas and quadriceps were automatically extracted from the preoperative CT using convolutional neural networks (CNN) and were corrected manually by the experienced surgeon. The muscle volumetric atrophy ratio was defined as the ratio of muscle volume of the affected side to that of the unaffected side. The muscle weakness ratio was defined as the ratio of muscle strength of the affected side to that of the unaffected side. The correlation coefficient between the muscle atrophy ratio and the muscle weakness ratio of each muscle were calculated. Results. The average muscle atrophy ratio was 84.5% (63.5%–108.2%) in gluteus maximus, 86.6% (65.5%–112.1%) in gluteus medius, 81.0% (22.1%–130.8%) in psoas major, and 91.0% (63.8%–127.0%) in quadriceps. The average muscle strength ratio was 71.5% (0%–137.5%) in hip flexion, 88.1% (18.8%–169.6%) in hip abduction, 78.6% (21.9%–130.1%) in hip extension and 84.3% (13.1%–122.8%) in knee extension. The correlation coefficient between the muscle atrophy and the ratio of each muscle strength between the affected and unaffected side were shown in Table 1. Conclusion. In conclusion, the muscle atrophy of gluteus medius muscle, psoas major muscle and quadriceps muscle significantly correlated with the muscle weakness in hip flexion. The muscle atrophy of psoas major muscle and quadriceps muscle also significantly correlated with the muscle weakness in knee extension. There were no significant correlation between the muscle atrophy and the muscle weakness in hip extension and abduction


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 13 - 13
1 Feb 2017
Hawkins E Bas M Roc G Cooper J Rodriguez J
Full Access

Introduction. Iliopsoas impingement is a well described cause of groin pain after direct anterior total hip arthroplasty (THA). We proposed to evaluate the incidence, natural history and response to treatment of iliopsoas impingement after direct anterior total hip arthroplasty. Methods. A retrospective chart review of 725 consecutive patients who underwent anterior approach total hip arthroplasty between 2009 and 2014 was conducted. All surgeries were performed by one of two surgeons. Patients were included if they underwent primary anterior approach THA and had a minimum of 2 years of follow up. Patients who had a posterior approach, revision surgery or had less than 2 years of follow up were excluded. Iliopsoas impingement was identified if patients reported groin pain at greater than 6 weeks of postoperative follow up and in association with pain with resisted seated hip flexion. The natural history and response to treatment was recorded for patients identified as having iliopsoas impingement. Results. 900 patients met inclusion criteria. Of these, 120 (13.4%) developed groin pain following direct anterior total hip arthroplasty. The average time of onset was at 21 months postoperatively. At 2 years postoperatively, 16% of patients had symptoms, whereas 84% had resolution. 28% of patients responded to structured physical therapy, 22% improved with home stretching, 19% improved after arthroscopic psoas release, 9% after psoas sheath injection, and 6% required acetabular component revision. Conclusion. In our study population, iliopsoas impingement is not an uncommon finding after direct anterior total hip arthroplasty, but nearly half of these patients responded well to home stretching or physical therapy. In some cases, psoas injection and arthroscopic release was necessary. Rarely, cup revision was required for symptomatic relief


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_3 | Pages 23 - 23
1 Mar 2021
Kelley S Maddock C Bradley C Gargan M Safir O
Full Access

The use of total hip arthroplasty in adolescents for end-stage degenerative hip disease is controversial with few reported outcomes in the literature. The purpose of the study was to report the outcomes of total hip arthroplasty in a cohort of adolescents managed by a multidisciplinary team of paediatric and adult orthopaedic surgeons from a single centre. A multidisciplinary clinic consisting of paediatric and adult hip surgeons was established in 2013 to identify, treat and prospectively follow adolescents who would potentially beneift from a total hip arthoplasty. To date 29 consecutive adolescent patients (20 female, 9 male, 32 hips) with end stage degenerative hip disease have undergone cementless primary total hip arthroplasty. Mean age at decision to treat was 15.7 years (age 11.4–18.5). Ten different underlying paediatric specific pathologies were documented including DDH, cerebral palsy, JIA, skeletal dysplasias, SCFE and idiopathic chondrolysis. Three patients had bilateral staged procedures. Clinical baseline and outcomes were measured using Oxford Hip Score (OHS), WOMAC score and ASKp scores. Radiographic follow-up was conducted at 6 weeks, 6 months and yearly thereafter. Post-operative complications were recorded. Twenty-five hips were eligible for minimum 2-year follow-up scoring at a mean 2.7 years (2.0–3.6 years). No intraoperative complications occurred. One case of recalcitrant postoperative psoas tendonitis occured. OHS improved from 25 (7–43) to 41 (23–48). WOMAC improved from 48 (12–8) to 12 (1–44), and ASKp improved from 78% (33–98%) to 93% (73–100%). Radiographic review revealed acceptable alignment of all components with no signs of loosening or wear. No revision of components was required. One patient died at 6 months post op from an unrelated condition. The early term results of total hip arthroplasty in adolescents from our multidisciplinary program are encouraging. Improvements in quality of life to normal values were seen as were hip scores consistent with satisfactory joint function. Depite the range of complex and varied causes of arthritis seen in this population the establishment of combined paediatric and adult orthopaedic surgical teams appears to be a successful model to manage end-stage degenerative hip disease in adolescents


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 135 - 135
1 Feb 2017
Varadarajan KM Patel R Zumbrunn T Rubash H Malchau H Freiberg A Muratoglu O
Full Access

Introduction. Dual-mobility (DM) liners provide increased range of motion and stability. However, large head diameters have been associated with anterior hip pain due to impingement with surrounding soft-tissues, particularly the iliopsoas. Further, during hip extension the liner can get trapped due to anterior soft-tissue impingement that resists rotation being imparted to the liner from posterior stem-liner contact. Over time this can cause liner rim damage, leading to intra-prosthetic dislocation of the small diameter inner head. To address this, an anatomically contoured dual mobility (ACDM) liner was designed to reduce the volume of the liner below the equator that can interact with soft-tissues (Fig. 1). In this study, we utilized finite element analysis to evaluate tendon-liner contact pressure and tendon stresses with ACDM and conventional designs during hip extension, wherein the posterior edge of liner is in contact with the stem while the anterior edge is exposed to the soft-tissue. Methods. The average uniaxial stiffness (350 N/mm), and average dimensions (width × thickness = 14mm × 4mm) of 10 cadaver psoas tendon samples were determined in a separate study. The iliopsoas tendon was modelled as a Yeoh hyper-elastic material, and the material constants were tuned to match the experimental uniaxial test data. Cadaver specific FEA models were created for 5 specimens (10 hips) using computed tomography (CT) scans. The implant components were modeled as being rigid relative to the iliopsoas tendon. The iliopsoas tendon was modelled as extending from its insertion point on the lesser trochanter to the psoas notch on the pelvis for hip flexion angles of −15°, 0°, 15° and 30°. Appropriately sized DM components were implanted virtually for each specimen. Once placed in its proper position, the liner was rotated about the flexion axis until it contacted the stem posteriorly to represent its orientation during hip extension (Fig. 2). A 500N tensile load was applied to the iliopsoas tendon and the average/max stresses within the tendon, and average/max contact pressures between the tendon and liner were measured. Results. At all hip flexion angles from −15° to 30°, the tendon-liner contact pressure and tendon stresses were lower with the ACDM liners compared to the conventional liner. Contact pressure and tendon stress decreased for both liner designs with increasing hip flexion angle. At −15° flexion angle, the average contact pressure was 42.3% lower (0.36Mpa), and the maximum contact pressure was 45.1% (8.5Mpa lower), with the ACDM compared to conventional liner design. Similarly, at −15° flexion angle the average vonMises pressure in the tendon was 32.5% lower (14.8Mpa), and the maximum vonMises stress in the tendon was 55.7% (159Mpa lower) with the ACDM design. (Fig 3). Discussion. This study utilized cadaver specific FEA models to evaluate interaction between the iliopsoas tendon and conventional and ACDM liners during hip extension. The results showed a notable reduction in contact pressure and tendon stress resulting from reduced volume and more soft-tissue friendly profile of the ACDM design. Thus, the ACDM design may be able to reduce undesirable soft-tissue interaction with dual mobility liners


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 497 - 497
1 Dec 2013
Rathod P Deshmukh A Robinson J Stirton J Rodriguez J
Full Access

Introduction. Acetabular component position is an important determinant of stability, wear and impingement following total hip arthroplasty (THA). Its optimum position and size in direct anterior approach (DAA) THA has not been clearly described in previous studies. Our aim was to study the evolution of the same with reference to stability and impingement as a part of a single surgeon's learning curve. Methods. Clinical and radiographic records of first 300 consecutive DAA THAs performed by a single surgeon from April 2009 to April 2011 were reviewed from a prospective database at a single center. Radiographic analysis was done by two observers to determine acetabular inclination and anteversion on 6 week postoperative standing radiographs. Native femoral head size, measured on preoperative radiographs after adjusting for magnification, was used to calculate the native acetabular cup size. The study population was divided into three groups; Group A– 1. st. 100 DAA THA cases, Group B – 2. nd. 100 and Group C – 3. rd. 100 corresponding to the use of intraoperative anterior stability assessment (Group B and C) and change in the cup size strategy (Group C). The incidence of instability and psoas impingement (PI) –related groin pain at 2 year follow-up was determined for the three groups. Statistical analysis was done to see if there were differences in these clinical and radiographic outcome measures in the three groups. Results. Mean values for abduction were similar in all the groups. Mean anteversion was significantly lower in Group B [12.5° (± 3.3°)] and C [13.6 °(± 2.3°)] as compared to group A [24.3°(± 7.5°)]. The difference between the implanted cup size and calculated native cup size was significantly higher in Group A [5.2(± 2.1) mm] and group B [5.8 (± 2.60 mm] as compared to group C [1.4 (± 1.4) mm] (Figure 1). There were 2 anterior dislocations in group A with none in the other groups. The incidence of PI-related groin pain was higher in group B (12%) as compared to group A (2%) and group C (2%). For PI related groin pain, an arthroscopic psoas release was performed in 3 patients and cup revision in 1 patient. Discussion. For optimum anterior stability, the target cup anteversion is lower in the DAA. Increasing the cup size makes the use of large heads possible. However, the implanted cup size should be as close to the native cup size with DAA THA to avoid anterior overhang (psoas impingement) or posterior overhang (cup-neck impingement and anterior instability)


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 80 - 80
1 May 2012
Cobb J
Full Access

Background. In large diameter hip arthroplasty, the femoral head size and shape have to be optimised to avoid neck on socket impingement if the head is too small, or psoas tendonopathy if the head is too large, overhanging the normal head neck junction in the sagittal plane. Currently there is no published guideline to help the surgeon select an optimal size femoral head. Instead, the novice surgeon may inadvertently oversize the femoral component through fear of notching the femoral neck—causing psoas impingement, especially in female patients. We sought to provide anatomically based advice for surgeons to optimise both the position of the femoral head and the head neck ratio. Materials and Methods. 100 hips were reviewed. Fifty radiographically normal hips in elderly patients with fractures of the contralateral side and 50 hips from patients whose contralateral side was arthritic secondary, either to Cam or pincer type impingement, or DDH. The head neck ratios were calculated using two methods: the plain AP radiographs were measured on PACS (Picture Archiving and Communication System) and CT scans obtained as part of the work up to hip surgery were measured in validation. The head neck ratio was calculated by dividing the diameter of the widest point across the femoral head by the narrowest part across the femoral neck. The HNR of 39 patients who attended a painful MOM clinic were also reviewed. Results. The normal mean HNR is 1.40 (min 1.22, max 1.58). Hips contralateral to a CAM type deformity have smaller HNRs (mean 1.30, min 1.23, max 1.41), while those on the other side of a DDH are larger, (mean 1.47, min 1.40, max1.53). In our painful MOM group only seven of these patients (18%) had a HNR within 1.45-1.5, and only 13 (33%) had a HNR between 1.4-1.5. Conclusions. There appears to be an optimal head neck ratio in the normal hip that is sufficient for normal function as defined by the absence of any arthritic change in either hip by the seventh decade. We recommend that a HNR of 1.45-1.5 (taking into consideration cartilage thickness) should be used to calculate the optimal femoral head size. This algorithm can be applied when resurfacing hips or when using large diameter MOM arthroplasty. Although the causes for a painful big ball arthroplasty may be multifactorial, there does appear to be a correlation between a painful joint and inappropriate HNR


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_10 | Pages 44 - 44
1 Jun 2018
Hofmann A
Full Access

Since 1997, a patented rim flared cup has been used for both primary and revision total hip arthroplasty with great success. The concept was based on a “stretched” hemispherical geometry to improve initial contact between cup and bone. This improved geometry provided a 1 mm press fit predominantly at the perimeter of the acetabulum much like the footprint of the native anatomic acetabulum. Thousands of these were implanted. A second version of this concept was introduced in August 2011. This similarly “stretched” geometry provides 1.6 mm of press fit. Building on what was learned from the original design, this updated, stretched geometry was created with a single radius for a smooth transition from the apex to the peripheral press fit. Porous coating is the key to implant durability. With this aggressive “sticky” porous coating, only 0.6 mm of press fit is required. This porous coating has 60% porosity, and 150–400 mm pore size. It has a tensile strength of 5000 psi (The FDA requires a minimum of 2900 psi) and a mean thickness of 0.8 mm. Three thousand cups have been implanted with the author contributing 400. In our own primary subgroup done in 2014–15, 142 had 2–4 year follow up with zero loosening. There was one infection and 2 dislocations. One implant was revised on a patient with psoas tendonitis from an oversized cup. At retrieval it showed excellent ingrowth into the porous coating with 38% ingrowth. This graduated rim fit concept has a proven track record spanning 2 decades and provides a stable and reproducible acetabular construct


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 106 - 106
1 Feb 2017
Le D Smith K Mitchell R
Full Access

Introduction. Orientation of the acetabular component in total hip arthroplasty has been shown to influence component wear, stability, and impingement. Freehand placement of the component can lead to widely variable radiographic outcomes. Accurate abduction, in particular, can be difficult in the lateral decubitus position due to limited ability to appreciate and control positional obliquity of the pelvis. A CT-based mechanical navigation device has been shown to decrease cup placement error. This is an independent report of a single-surgeon's radiographic results using the device to control cup abduction. Patients and Methods. Sixty-four (64) consecutive elective THRs in 58 patients were performed via a supercapsular percutaneously-assisted (SuperPATH) surgical approach. Intraoperatively, the acetabular components were aligned with the aid of the CT-based mechanical navigation device (HipXpert; Surgical Planning Associates, Medford, MA). The cup orientation was then further adjusted to ensure that the anterior rim of the acetabular component was not prominent to avoid psoas impingement. Postoperatively, radiographic abduction was measured on standing postoperative radiographs. Results. Measured on standing postoperative radiographs, the cup radiographic abduction angle averaged 42.7° with a standard deviation of ± 3.9° and a range of 35° to 51°. Conclusions. Total hip arthroplasty using a CT-based navigation device as a guide for abduction led to cup implantation within a very narrow abduction range. This navigation device deserves more widespread interest and study, as acetabular component malposition remains a major concern in THR


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_6 | Pages 12 - 12
1 Apr 2018
Lazennec J Kim Y Pour AE
Full Access

Introduction. Few studies are published about total hip arthroplasties (THA) in Parkinson's disease as it is often considered as a contraindication for hip replacement. THA for fracture is reported as a high complication rate surgery. Regarding bone quality these cases are assimilated to elderly patients and cemented implants are generally preferred. However, due to the improved length and quality of life, we face more potential indications for joint replacement. The aim of this study is to report our experience of cementless dual mobility implants for primary THAs for osteoarthrosis and THA revisions focusing on the risks and benefits of surgery. Material and methods. 65 THA were performed in 59 patients (34 men, 25 women, mean age 73 years, 55–79). Mean latest follow-up was 8,3 years (4–14). Indications were 42 primary THA (osteoarthrosis) and 21 revisions (11 recurrent dislocation, 6 acetabular PE wear, 4 femoral loosening). Surgical approach was always antero-lateral. All patients were implanted with the same dual mobility cementless cup. The same cementless corail-type stem was used for primary THA cases. All the cemenless implants were hydroxyapatite coated. The disability caused by the disease was classified according to Hoehn and Yahr. (19 stage 1, 21 stage 2,16 stage 3). Results. 2 patients were lost for follow-up before 2 years. general complications were 3 pulmonary infection, 7 urinary tract infection, 12 cognitive impairment and 2 sacral pressure ulcer. A post-op. wound infection (E Coli) required an early revision in 2 cases without secondary consequencies (7 and 9 years follow-up). We did not observe early or late THA dislocation except in one case at 9 years follow-up (intraprosthetic dislocation due to an increase of ilio psoas muscle retraction requiring a revision of the dual mobility mechanism). We did not observe loosening cases of the cementless cup. 4 patients fell and fractured the femur. The cementless cup was not affected. 10 patients died. Good to excellent pain relief was achieved in 53/57cases at 2 years and in 40/47 cases at latest follow-up. The progression of neurological disability was observed in most of cases. At the latest follow-up for the 47 remaining patients, we had 5 stage 1, 12 stage 2, 21 stage 3,9 stage 4. Discussion. According to literature infection and dislocation are the main concerns for THA in Parkinson patients. This study does not report any trauma cases; this may explain the rather good results on a mean follow-up to more than 8 years. Nevertheless progression of Parkinson's disease is the rule, with significant disability or even death (10 /57 cases). Cementless fixation is possible even on the acetabular side. The poor bone quality of these patients was not an argument against hydroxyapatite coated implants. Conclusion. THA in Parkinson's disease is a challenging surgery due to associated comorbidity. For all patients the functional status improved in the early follow-up and declined with the disease progression. Cementless dual mobility cups and femoral stems can be used with a very low rate of mechanical complication


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 28 - 28
1 Apr 2018
Yoon P Park J Kim C
Full Access

We report a case of fatal heart failure caused by cobalt intoxication after revision THR in the patient who successfully underwent re-revision THR. 53-year old male presented to emergency room in our hospital with progressive shortness of breath. Symptom was started about 6 months ago so he visited local hospital. He worked up for worsening dyspnea. Simple chest radiograph and enhanced heart MRI study were performed and they showed bilateral pericardial and pleural effusion. There was no evidence of ischemic change. Transthoracic echocardiogram showed the evidence of heart failure, left ventricular ejection fraction(EF) was 40%. He was admitted at local hospital and started on vasopressors but urine output was decreased and follow-up echocardiogram showed a 25% of EF. Patient recommended heart transplantation and transferred our hospital emergency room. He underwent sequential bilateral total hip arthroplasties using CoP bearing surfaces. At 12 years postoperatively, he presented to the other hospital with acute onset of left hip pain. He was diagnosed ceramic head fracture on his left hip. Head and liner change revision surgery was performed using Cobalt-Chrome alloy 28mm metal head and Protruded cross-linked polyethylene liners. In our hospital, the patient admitted cardiovascular department of internal medicine. Patient complained nonspecific fatigue and general weakness but had no other symptoms such as visual and hearing loss, cognitive dysfuction. During work-up, patient presented progressive left hip pain and complaint of discomfort for the mass on the left groin. He also complained Left leg weakness and numbness. Simple radiograph and enhanced CT study was done. Simple radiograph image shows radiodense area around the hip joint and radiologist suspected heterotopic ossification. The cardiovascular department consulted orthopedic department. In the image findings showed huge mass combined hemorrhagic component lining acetabular component extending psoas compartment and eccentric wear on cobalt-chrome alloy metal head. Also highly radiodense material was seen around neck inferor portion and severly deformed metal head was seen. It was highly suspected that metal related granuloma, which means severe metallosis. Performed heavy metals screen, cobalt levels were 397,800 μg/Land chrome levels were 236,000 μg/L suggesting cobalt toxicity. Hip joint aspiration was done for decompression as radiologic intervention and EDTA (ethylenediamine tetraacetate) chelation therapy started immediately. After 10 cycle chelating therapy, metal level was lowered cobalt levels by 255.2μg/L and chrome levels by 39.5 μg/L. When hospital day after 134, Medical condition of the patient was getting improved, we underwent revision surgery using ceramic on ceramic bearing surface. The patient discharged postoperative 79 days. Final heavy metals screen results were 27.79μg/L on cobalt and 22.17μg/L on chrome. Although there were also reported a good clinical result of revision surgery using MoP bearing, and some surgeons reluctant to use CoC articulation because of concerns about re-fracture of ceramic. But take into account like this devastating complication after cobalt-chrome wear caused by remained ceramic particles, we should carefully select which bearing is safer