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Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_4 | Pages 133 - 133
1 Apr 2019
Taki N Mitsugi N Mochida Y Yukizawa Y Sasaki Y Takagawa S
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INTRODUCTION. Recently, short shaped stem becomes popular in total hip arthroplasty (THA). Advantages of the short stem are preserving femoral bone stock, thought to be less thigh pain, suitable for minimally invasive THA. However, bony reaction around the short stem has not been well known. The purpose of this study was to compare the two years difference of radiographic change around the standard tapered round stem with the shorter tapered round stem. MATERIALS AND METHODS. Evaluation was performed in 96 patients (100 joints) who underwent primary THA. Standard tapered round stem (Bicontact D stem) was used in 44 patients from January 2011 to May 2013. Shorter stem (Bicontact E stem) was used in 56 patients from May 2015 to March 2016. The proximal shapes of these two stems are almost the same curvature. The mean age at surgery was 64 years. The mean BMI at surgery was 24.0 kg/m. 2. Eighty-six patients had osteoarthrosis and 10 patients had osteonecrosis. Evaluation was performed 2 years after surgery with standard AP radiographs. The OrthoPilot imageless navigation system was used during surgery. Evaluation of the stem fixation, stress shielding, and cortical hypertrophy were carried out. RESULTS. There were no differences of patient characteristics between the standard D stem group and the shorter E stem group. All 100 stems showed bony stable fixation two years after surgery. No subsidence was observed in both groups. No clear zone was observed around the stems in both groups. Cortical hypertrophy was observed 19 patients (43.2%) with the standard D stem group and 13 patients (23.2%) with the shorter E stem group. The standard D stem group showed higher incidence of cortical hypertrophy. Stress shielding was observed 35 patients (80%) with the standard D stem group and 42 patients (75%) with the shorter E stem group. The number of grade 1 and grade 2 stress shielding cases were 13 and 22 with the standard D stem group and 10 and 32 with the shorter E stem group, respectively. There were no grade 3 stress shielding case in both groups. Regarding the incidence of stress shielding, there was no difference between the two groups. DISCUSSION. This study demonstrated that the shorter stem showed less incidence of cortical hypertrophy compared to the standard stem. With radiographic evaluation, both standard and shorter stem showed good fixation. The meaning of cortical hypertrophy, whether it is a good reaction for the femur or not, has not been clarified yet. Less bony reaction around the shorter stem may suggest the potential for better clinical performance of the shorter stem compare to the standard stem


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_8 | Pages 104 - 104
11 Apr 2023
Vadgaonkar A Faymonville C Obertacke U
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Osteoarthritis (OA) is the most common disorder of the Sternoclavicular Joint (SCJ). In our case-control study, we evaluated the relationship between clavicular length and OA at the SCJ.

CT scans of adults presenting to the Emergency Department of our hospital were examined to look for OA, defined as the presence of osteophytes, subchondral cysts, or cortical sclerosis at the SCJ. Medial-most and lateral-most points of the clavicle were marked on the slices passing through the SC and AC joints respectively. Using x, y, and z-axis coordinates from the DICOM metadata, clavicular length was calculated as the distance between these two points with 3D geometry.

Preliminary data of 334 SCJs from 167 patients (64% males, 36% females) with a mean age of 48.5 ± 20.5 years were analysed. Multivariate regression models revealed that age and clavicular length were independent risk factors for OA while gender did not reach statistical significance. A 1mm increase in length was associated with 9% and 7% reduction in the odds of developing OA on the left and the right respectively. Comparing the mean clavicular length using t-test showed a significantly shorter clavicle in the group with OA (145.8 vs 152.7, p=0.0001, left and 144.2 vs 150.3, p=0.0007, right).

Our data suggest that the risk of developing OA at the SCJ is higher for shorter clavicles. This could be of clinical relevance in cases of clavicular fracture where clavicular shortening might lead to a higher risk of developing OA. Biomechanical studies are needed to find out the mechanism of this effect.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_11 | Pages 13 - 13
7 Jun 2023
Diffley T Ferry J Sumarlie R Beshr M Chen B Clement N Farrow L
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Appropriate surgical management of hip fractures has major clinical and economic consequences. Recently IMN use has increased compared to SHS constructs, despite no clear evidence demonstrating superiority of outcome. We therefore set out to provide further evidence about the clinical and economic implications of implant choice when considering hip fracture fixation strategies.

A retrospective cohort study using Scottish hip fracture audit (SHFA) data was performed for the period 2016–2022. Patients ≥50 with a hip fracture and treated with IMN or SHS constructs at Scottish Hospitals were included. Comparative analyses, including adjustment for confounders, were performed utilising Multivariable logistic regression for dichotomous outcomes and Mann-Whitney-U tests for non-parametric data. A sub-group analysis was also performed focusing on AO-A1/A2 configurations which utilised additional regional data. Cost differences in Length of Stay (LOS) were calculated using defined costs from the NHS Scotland Costs book. In all analyses p<0.05 denoted significance.

13638 records were included (72% female). 9867 received a SHS (72%).

No significant differences were identified in 30 or 60-day survival (Odds Ratio [OR] 1.05, 95%CI 0.90–1.23; p=0.532), (OR 1.10, 95%CI 0.97–1.24; p=0.138) between SHS and IMN's.

There was however a significantly lower early mobilisation rate with IMN vs SHS (OR 0.64, 95%CI 0.59–0.70; p<0.001), and lower likelihood of discharge to domicile by day-30 post-admission (OR 0.77, 95%CI 0.71–0.84; p<0.001). Acute and overall, LOS were significantly lower for SHS vs IMN (11 vs 12 days and 20 vs 24 days respectively; p<0.001). Findings were similar across a sub-group analysis of 559 AO A1/A2 fracture configurations.

Differences in LOS potentially increases costs by £1230 per-patient, irrespective of the higher costs of IMN's v SHS.

Appropriate SHS use is associated with early mobilisation, reduced LOS and likely with reduced cost of treatment. Further research exploring potential reasons for the identified differences in early mobilisation are warranted.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 400 - 400
1 Sep 2009
Confalonieri N Manzotti A Motavalli K
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The Authors performed a matched paired study between 2 groups UKR or CA-TKR implanted with a mini-incision (MICA group) in the treatment of isolated medial compartment knee arthritis. The Authors hypothesized that UKR offers a real less invasive surgery with lower economical costs despite a worse limb/implant alignment. Furthermore at a minimum 40 months follow-up they hypothesized that this small implant guarantees still both better clinical score and patient satisfaction than in the MICA group.

Thirty two patients with isolated medial compartment knee arthritis who underwent to a medial UKR from February 2001 to September 2002 were included in the study (UKR group). In all 32 knees the arthritic change was graded according to the classification of Älback 1. Arthritic change did not exceed grade IV in the medial compartment and grade II in the patello-femoral compartment. All patients had an asymptomatic patello-femoral joint. All patients had a varus deformity lower than 8° and a body mass index lower than 30. No patient had any clinical evidence of ACL laxity or flexion deformity and all had a preoperative range of motion of a least 110°. At a minimum follow-up of 48 months, every single patients in group A was matched with a patient who had undergone a computer assisted TKR performed with a less invasive approach (shorter than 12 cm) for an isolated medial compartment knee arthritis between August 1999 and September 2002 (MICA group) in our hospital. At latest follow-up the clinical outcome was evaluated using both the Knee Society Score and a dedicated UKR score developed by the Italian Orthopaedic UKR Users Group (GIUM). The HKA angle and the Frontal Tibial Component angle (FTC) were measured at latest follow up on long leg standing anterior-posterior radiographs and the mean values between the 2 surgeons assessments were used as final values. Furthermore during the hospital staying we registered in both the groups when each patient was standing comfortably in full weight-bearing according to a self- answered questionnaire and the data were compared. Statistical analysis of the results was performed using parametric test (Student’s t-test). A statistical comparison of the percentage of results for the GIUM score was performed using the Chi-square test. A statistically significant result was given a p≤ 0.05.

Both hospital stay and operative time were statistically longer obviously in MICA group. In the UKR group the mean surgical time was 51.5 minutes (range: 36–75) (p< 0.001) while in the MICA group was 108.8 minutes (range: 80–132) (p< 0.001). In the UKR group the patients remained in the hospital for a mean of 5.1 days (range: 3–7) and in the MICA group 8.2 days (range: 4–16). At the latest follow-up the mean Knee Society Score was 80.5 (range: 70–100) and 78.4 (range: 70–87) for group A and B respectively. No statistically significant difference was seen for the Knee Society score between the 2 groups (p=0.08). The mean Functional score was 83.5 (range: 73–100) for group A and 78.8 (range: 59–90) for group B. A statistically significant difference was seen for the Functional score with superior results for group A (p=0.02). A statistically significant difference was seen for the GIUM score with better results for group A (p=0.01). The mean GIUM score was 76 (range: 67–90) and 73.02 (mean: 65–85) for group A and B respectively. At latest follow up the mean HKA angle was 176.8° for group A (range: 174°–182°) and 179.3° for group B (range 177–182) (p< 0.001). The mean FTC angle was 86.9° (range: 84°–90°) and 89.4° (range: 87°–92°) for group A and B respectively (p< 0.001). All TKR implants were positioned within 4 degrees of a HKA angle of 180° and FTC angle of 90°.

At the latest follow-up (minimum 48 months) no statistically significant difference was seen in the postoperative Knee Society score for either group. However, significant differences were seen between the 2 groups in the functional results and in the GIUM score with better results in the UKR group. All the patients achieved a range of motion greater than 120° and could walk for longer distances. During the hospital staying in this group the patients reported a statistically significant earlier full weight-bearing. This was despite a significant less accurate limb alignment. In addition to inferior results for the computer assisted mini-invasive TKR group the costs of the procedure were obviously greater because of the expensive implants and technology along with statistically significant longer surgical times and hospital stay


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 267 - 267
1 Sep 2012
Nymark T Lindoe L Al-Maleh A
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Introduction

The length of hospital stay following a hip fracture has decreased significantly during the past decades. Knowing that a hip fracture patient is often one with several comorbidities and high mortality, is it possible to further decrease the length of stay without compromising the quality of care?

Setting

Prior to November 2007 a hip fracture patient at Svendborg Hospital would be admitted to the orthopedic department. Postoperatively the patient would be treated by the orthopedic surgeons. If needed a geriatric consult could occur. If the patient was eligible she could be transferred to the geriatric department for further rehabilitation.

After November 2007 eight orthopedic beds were dedicated to hip fracture patients, in an orthogeriatric setting. The patient was treated operatively by the orthopedic surgeons, and then a geriatric consultant was responsible for the rest of the stay. Nurses and therapists were dedicated to the care of hip fracture patients, and had recieved special training regarding. The patient would stay in the same bed throughout the hospitalisation.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_6 | Pages 41 - 41
1 Mar 2017
Taki N Mitsugi N Mochida Y Ota H Shinohara K Sasaki Y Ishigatsybo R
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INTRODUCTION

Recently, the short stem has become popular in total hip arthroplasty (THA). The advantages of the short stem are that it preserves femoral bone stock, possibly results in less thigh pain, and is suitable for minimally invasive THA. However, because of the short stem, malposition may happen during surgery. The purpose of this study was to compare the stem alignment, which was measured by CT, between the standard tapered round stem and the shorter tapered round stem.

MATERIALS AND METHODS

CT evaluation was performed in 28 patients (29 joints) who underwent primary THA. The standard tapered round stem (Bicontact D stem) was used in 13 patients. The shorter stem (Bicontact E stem) was used in 16 patients (17 joints). The proximal shapes of these two stems have almost the tame curvature. The mean age at surgery was 68 years. The mean BMI at surgery was 23.3 kg/m2. Eighteen patients had osteoarthrosis, 3 patients had osteonecrosis, and 1 patient had femoral neck fracture. All surgeries were performed in the supine position with the direct anterior approach. The OrthoPilot imageless navigation system was used during surgery. Evaluation of the stem antetorsion angle (AA), flexion angle (FA), and varus angle (VA) were carried out.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIX | Pages 63 - 63
1 Jul 2012
McKenna R Latif A McLeery M Chambers M Rooney B Leach W
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Aim

We aim to compare post-operative length of stay and cardiopulmonary morbidity in patients randomised to either navigated or conventional total knee arthroplasty (TKA).

Method

Patients undergoing primary TKA for osteoarthritis were prospectively assigned randomly to either navigation-guided or control groups and blinded to this.

All patients received a PFC implant (DePuy, Warsaw, IN). In the control group the standard femoral intramedullary and tibial extramedullary alignment rod was used. In the navigation group, the BrainLab (Munich, Germany) navigation system was used. All operations were carried out by one of two consultant orthopaedic knee surgeons.

Length of post operative hospital stay and the development of cardiopulmonary complication were recorded and groups compared.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVIII | Pages 42 - 42
1 Jun 2012
McKenna R Latif A McLeery M Chambers M Rooney B Leach W
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We aim to compare post-operative length of stay and cardiopulmonary morbidity in patients randomised to either navigated or conventional total knee arthroplasty (TKA).

Patients undergoing primary TKA for osteoarthritis were prospectively assigned randomly to either navigation-guided or control groups and blinded to this.

All patients received a PFC implant (DePuy, Warsaw, IN). In the control group the standard femoral intramedullary and tibial extramedullary alignment rod was used. In the navigation group, the BrainLab (Munich, Germany) navigation system was used. All operations were carried out by one of two consultant orthopaedic knee surgeons.

Length of post operative hospital stay and the development of cardiopulmonary complication were recorded and groups compared.

100 patients were recruited (55 control vs 45 navigated). Patient demographics were similar in both groups.

Mean length of stay was 7 days in the control group (range 3-101), 5 days in the navigation group (range 3-10). The mode was 4 days in both groups.

7 patients (13%) stayed for >7 days in the control group, 3 patients (7%) stayed >7 days in the navigation group(p=0.339).

4 patients(7%) required >10 days inpatient stay in the control group, 0 patients required to stay in hospital for longer than 10 days in the navigation group(p=0.069).

The causes for the length of stay exceeding 10 days were pulmonary embolus in 3 patients, and chest infection in 1 patient.

Patients undergoing navigation-guided TKA required shorter post-operative inpatient stays than those undergoing arthroplasty using conventional techniques. Fewer patients in the navigation group required stays longer than 7 or 10 days. The difference in post-operative stay was associated with fewer respiratory complications in the navigated group.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 400 - 400
1 Dec 2013
Meneghini M Lovro L Licini D
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Introduction:

Although cementless total hip arthroplasty (THA) is well accepted, the optimal femoral component design remains unknown. Among early complications, loosening and periprosthetic fracture persist and are related to implant design. The purpose of this study is to compare the anatomic fit and early subsidence of two different stem designs: a modern, short taper-wedge design and a traditional fit-and-fill design.

Methods:

A retrospective cohort study of 129 consecutive cementless THAs using two different femoral stems was performed. A modern taper-wedge stem was used in 65 hips and a traditional proximal fit-and-fill stem was used in 64 hips. Radiographic analysis was performed at preoperative, immediate postoperative and 1-month postoperative intervals. The radiographic parameters of bone morphology via the canal-flare index, implant subsidence at 1 month, sagittal alignment, and the “anatomic fit” metrics of canal fill and associated gaps were measured and recorded.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXII | Pages 58 - 58
1 May 2012
Parker L Smitham P McCarthy I Garlick N
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Conventionally, medial malleolus fractures are treated surgically with anatomical reduction and internal fixation using screws. There seems to be no consensus, backed by scientific study on the optimal screw characteristics in the literature.

We retrospectively examined case notes and radiographs of 48 consecutive patients taken from our trauma database (21 male, 27 female) with an average age of 50 years (range 16-85) who had undergone medial malleolus fracture fixation with screws at the Royal Free Hospital, London between January 2009 and June 2010.

The most commonly used screw was the AO 4.0 mm diameter cancellous partially-threaded screw in 40, 45 and 50 mm lengths (40 mm n = 28, 45 mm n = 26, 50 mm n = 23) with the threads passing beyond the physeal scar in all cases. Incomplete reduction defined as > 1mm fracture displacement was observed on post-operative x-rays in 12 out of 48 cases (25%), all of which relied on partially-threaded screw fixation. In 5 cases where AO 4.0 mm diameter fully-threaded screws engaging the physeal scar had been used, no loss of reduction was observed.

This unusual, occasional use of fully-threaded screws prompted us to investigate further using a porcine model and adapted pedo-barographic transducer. We compared pressures generated within the fracture site using AO 4.0 mm partially-threaded cannulated screws, 4.0 mm partially-threaded cancellous screws and 4.0 mm fully-threaded cancellous screws.

Fully-threaded cancellous 4.0 mm diameter screws generated almost 3 times the compression of a partially-threaded cancellous screw with superior stability at the fracture. Partially-threaded screws quickly lost purchase, compression and stability particularly when they were cannulated. We also observed that screw thread purchase seemed enhanced in the physeal region.

We conclude that fully-threaded cancellous 4.0 mm AO screws are superior to longer partially-threaded screws and that use of cannulated 4.0 mm partially-threaded screws should be avoided in fixation of medial malleolus fractures.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_14 | Pages 16 - 16
1 Dec 2015
Shivji F Weston S Addison T Erskine R Milner S
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Purpose

Ankle and hindfoot surgery is associated with severe post-operative pain, leading to a reliance on opiate analgesia and its side effects, longer hospital stays, and patient dissatisfaction. Popliteal sciatic nerve blockade has the potential to resolve these issues. We present our experience with using a continuous local anaesthetic nerve block delivered by an elastomeric pump in patients undergoing major foot and ankle surgery.

Methods

All patients undergoing major ankle or hindfoot surgery during a one-year period under a single surgeon were eligible for a continuous popliteal block. An ultrasound-guided popliteal nerve catheter was inserted immediately before surgery and a bolus of bupivacaine infiltrated. Using a 250ml elastomeric pump, a continuous infusion was started immediately post operatively and terminated 48 hours later. Prospective data including post-operative analgesia, nausea and vomiting (PONV), length of stay (LOS), pain scores, and patient satisfaction were recorded daily for 48 hours post operatively.


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_12 | Pages 17 - 17
1 Dec 2022
Kowalski E Dervin G Lamontagne M
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One in five patients remain unsatisfied due to ongoing pain and impaired mobility following total knee arthroplasty (TKA). It is important if surgeons can pre-operatively identify which patients may be at risk for poor outcomes after TKA. The purpose of this study was to determine if there is an association between pre-operative measures and post-operative outcomes in patients who underwent TKA. This study included 28 patients (female = 12 / male = 16, age = 63.6 ± 6.9, BMI = 29.9 ± 7.4 kg/m2) with knee osteoarthritis who were scheduled to undergo TKA. All surgeries were performed by the same surgeon (GD), and a subvastus approach was performed for all patients. Patients visited the gait lab within one-month of surgery and 12 months following surgery. At the gait lab, patients completed the knee injury and osteoarthritis outcome score (KOOS), a timed up and go (TUG), and walking task. Variables of interest included the five KOOS sub-scores (symptoms, pain, activities of daily living, sport & recreation, and quality of life), completion time for the TUG, walking speed, and peak knee biomechanics variables (flexion angle, abduction moment, power absorption). A Pearson's product-moment correlation was run to assess the relationship between pre-operative measures and post-operative outcomes in the TKA patients. Preliminary analyses showed the relationship to be linear with all variables normally distributed, as assessed by Shapiro-Wilk's test (p > .05), and there were no outliers. There were no statistically significant correlations between any of the pre-operative KOOS sub-scores and any of the post-operative biomechanical outcomes. Pre-operative TUG time had a statistically significant, moderate positive correlation with post-operative peak knee abduction moments [r(14) = .597, p < .001] and peak knee power absorption [r(14) = .498, p = .007], with pre-operative TUG time explaining 36% of the variability in peak knee abduction moment and 25% of the variability in peak knee power absorption. Pre-operative walking speed had a statistically significant, moderate negative correlation with post-operative peak knee abduction moments [r(14) = -.558, p = .002] and peak knee power absorption [r(14) = -.548, p = .003], with pre-operative walking speed explaining 31% of the variability in peak knee abduction moment and 30% of the variability in peak knee power absorption. Patient reported outcome measures (PROMs), such as the KOOS, do indicate the TKA is generally successful at relieving pain and show an overall improvement. However, their pre-operative values do not correlate with any biomechanical indicators of post-operative success, such as peak knee abduction moment and knee power. Shorter pre-operative TUG times and faster pre-operative walking speeds were correlated with improved post-operative biomechanical outcomes. These are simple tasks surgeons can implement into their clinics to evaluate their patients. Future research should expand these findings to a larger sample size and to determine if other factors, such as surgical approach or implant design, improves patient outcomes


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 272 - 272
1 Dec 2013
Connor E Boucher F Wuestemann T Crawford R
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Introduction. The Exeter cemented polished tapered stem design was introduced into clinical practice in the early 1970's. [i] Design and cement visco-elastic properties define clinical results [ii]; a recent study by Carrington et al. reported the Exeter stem has 100% survivorship at 7 years. [iii] Exeter stems with offsets 37.5–56 mm have length 150 mm (shoulder to tip). Shorter stems, lengths 95–125 mm, exist in offsets 30–35.5 mm. The Australian National Joint Replacement Registry recently published that at 7 years the shorter stems are performing as well as longer stems on the registry [iv]. Clinical observation indicates in some cases of shorter, narrower femora that fully seating a 150 mm stem's rasp in the canal can be difficult, which may affect procedural efficiency. This study investigates the comparative risk of rasp distal contact for the Exeter 150 mm stem or a 125 mm stem. Materials and Methods. Rasps for 37.5, 44, 50 mm offset, No.1, 150 mm length stems (Exeter, Stryker Orthopaedics, Mahwah NJ) were compared with shortened length models using SOMA™ (Stryker Orthopaedics Modeling and Analytics technology). 637 patients' CT scanned femora were filtered for appropriate offset and size by measuring femoral-head to femoral-axis distance and midsection cancellous bone width (AP view). These femora were analyzed for distal contact (rasp to cortices) for 150 mm and 125 mm models (Figure 1). The widths of the rasp's distal tip and the cancellous bone boundary were compared to assess contact for each femur in the AP and ML views; the rasp was aligned along an ideal axis and flexed in order to pass through the femoral neck (ML view only). Results. The sample size of appropriate patients totaled 238 femora. In the AP view, the rasp exhibited contact in 43 cases for a 150 mm stem but in 0 cases for a 125 mm stem; 95% of bones with contact were Champagne Fluted. In the ML view, rasp distal contact occurred in 52 femora for a 150 mm stem and in 1 femur for a 125 mm stem (Table 1). The difference was significant in both views with p < 0.001. Discussion. This study shows that a shortened stem design's rasp avoids distal contact. Shorter stem rasps resolved all cases where there was a risk of contact with a 150 mm rasp and reduced the likelihood of contact (one case compared to 52), AP and ML views respectively. These results indicate that shorter stems may address patients with champagne-fluted and/or excessively bowed femora, commonly found in the Asian population[v]. Contact avoidance may improve rasp seating height (AP view) and alignment with the femoral axis (ML view), thereby increasing procedural efficiency and producing an optimal cement mantle distally.[vi] The data shows that a total 29% of appropriate model patients would benefit from a shorter stem. Shorter cemented stems may effectively address the global population's needs in THR


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_3 | Pages 38 - 38
1 Mar 2021
Tavakoli A Faber K Langohr G
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Total shoulder arthroplasty (TSA) is an effective treatment for end-stage glenohumeral arthritis. The use of high modulus uncemented stems causes stress shielding and induces bone resorption of up to 63% of patients following TSA. Shorter length stems with smaller overall dimensions have been studied to reduce stress shielding, however the effect of humeral short stem varus-valgus positioning on bone stress is not known. The purpose of this study was to quantify the effect of humeral short stem varus-valgus angulation on bone stresses after TSA. Three dimensional models of eight male cadaveric humeri (mean±SD age:68±6 years) were created from computed tomography data using MIMICS (Materialise, Belgium). Separate cortical and trabecular bone sections were created, and the resulting bone models were virtually reconstructed three times by an orthopaedic surgeon using an optimally sized short stem humeral implant (Exactech Preserve) that was placed directly in the center of the humeral canal (STD), as well as rotated varus (VAR) or valgus (VAL) until it was contacting the cortex. Bone was meshed using a custom technique which produced identical bone meshes permitting the direct element-to-element comparison of bone stress. Cortical bone was assigned an elastic modulus of 20 GPa and a Poisson's ratio of 0.3. Trabecular bone was assigned varying stiffness based on CT attenuation. A joint reaction force was then applied to the intact and reconstructed humeri representing 45˚ and 75˚ of abduction. Changes in bone stress, as well as the expected bone response based on change in strain energy density was then compared between the intact and reconstructed states for all implant positions. Both varus and valgus positioning of the humeral stem altered both the cortical and trabecular bone stresses from the intact states. Valgus positioning had the greatest negative effect in the lateral quadrant for both cortical and trabecular bone, producing greater stress shielding than both the standard and varus positioned implant. Overall, the varus and standard positions produced values that most closely mimicked the intact state. Surprisingly, valgus positioning produced large amounts of stress shielding in the lateral cortex at both 45˚ and 75˚ of abduction but resulted in a slight decrease in stress shielding in the medial quadrant directly beneath the humeral resection plane. This might have been a result of direct contact between the distal end of the implant and the medial cortex under loading which permitted load transfer, and therefore load-reduction of the lateral cortex during abduction. Conversely, when the implant was placed in the varus angulation, noticeable departures in stress shielding and changes in bones stress were not observed when compared to the optimal STD position. Interestingly, for the varus positioned implant, the deflection of the humerus under load eliminated the distal stem-cortex contact, hence preventing distal load transfer thus precluding the transfer of load


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_1 | Pages 1 - 1
1 Feb 2021
Tavakoli A Faber K Langohr G
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Introduction. Total shoulder arthroplasty (TSA) is an effective treatment to restore shoulder function and alleviate pain in the case of glenohumeral arthritis [1]. Stress shielding, which occurs when bone stress is reduced due to the replacement of bone with a stiffer metallic implant, causes bone resorption of up to 9% of the humeral cortical thickness following TSA [2]. Shorter length stems and smaller overall geometries may reduce stress shielding [3], however the effect of humeral head backside contact with the resection plane has not yet been fully investigated on bone stress. Therefore, the purpose of this study was to quantify the effect of humeral head contact conditions on bone stresses following TSA. Methods. 3D models of eight male left cadaveric humeri (68±6 years) were generated from CT data using MIMICS. These were then virtually prepared for reconstruction by an orthopaedic surgeon to accept a short-stem humeral implant (Exactech Equinoxe® Preserve) that was optimally sized and placed centrally in the humeral canal. The humeral head was positioned in the inferior-medial position such that contact was achieved on the medial cortex, and no contact existed on the lateral cortex. Three different humeral head backside contact conditions were investigated (Figure 1); full backside contact (FULL), contact with only the inferior-medial half of the resection (INF), and contact with only the superior-lateral half of the resection (SUP). Cortical bone was assigned an elastic modulus of 20 GPa and a Poisson's ratio of 0.3. Trabecular bone was assigned varying stiffness based on CT attenuation [4]. A joint reaction force was then applied representing 45˚ and 75˚ of abduction [5]. Changes in bone stress, as well as the expected bone response based on change in strain energy density [6] was then compared between the intact and reconstructed states. Results. For cortical bone, the full backside contact altered bone stress by 28.9±5.5% compared to intact, which was significantly less than the superior (37.0±3.9%, P=0.022) and inferior (53.4±3.9%, P<0.001) backside contact conditions. Similar trends were observed for changes in trabecular bone stress relative to the intact state, where the full backside contact altered bone stress by 86.3±27.9% compared to intact, compared to the superior and inferior contact conditions, which altered bone stress by 115.2±45.0% (P=0.309) and 197.4±80.2% (P=0.024), respectively. In terms of expected bone response, both the superior and inferior contact resulted in an increase in bone volume with resorbing potential compared to the full contact (Figure 2). Discussion and Conclusions. The results of this study show that full humeral head backside contact with the humeral resection plane is preferable for short stem humeral TSA implants with the head in the inferior-medial position. As expected, the superior contact typically increased resorption potential in the medial quadrant due to the lack of load transfer, however interestingly the inferior contact increased resorption potential in both the lateral and medial quadrants. Analysis of implant micromotion showed that medial liftoff of the implant occurred, which resulted in a lack of load transfer in the most medial aspect of the resection plane. For any figures or tables, please contact the authors directly


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_8 | Pages 27 - 27
1 Aug 2020
Abdic S Athwal G Wittman T Walch G Raiss P
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The use of shorter humeral stems in reverse shoulder arthroplasty has been reported as safe and effective. Shorter stems are purported to be bone preserving, easy to revise, and have reduced surgical time. However, a frequent radiographic finding with the use of uncemented short stems is stress shielding. Smaller stem diameters reduce stress shielding, however, carry the risk of varus or valgus malalignment in the metadiaphyseal region of the proximal humerus. The aim of this retrospective radiographic study was to measure the true post-operative neck-shaft (N-S) angle of a curved short stem with a recommended implantation angle of 145°. True anteroposterior radiographs of patients who received RTSA using an Ascend Flex short stem at three specialized shoulder centres (London, ON, Canada, Lyon, France, Munich, Germany) were reviewed. Radiographs that showed the uncemented stem and humeral tray in orthogonal view without rotation were included. Sixteen patients with proximal humeral fractures or revision surgeries were excluded. This yielded a cohort of 124 implant cases for analysis (122 patients, 42 male, 80 female) at a mean age of 74 years (range, 48 – 91 years). The indications for RTSA were rotator cuff deficient shoulders (cuff tear arthropathy, massive cuff tears, osteoarthritis with cuff insufficiency) in 78 patients (63%), primary osteoarthritis in 41 (33%), and rheumatoid arthritis in 5 (4%). The humeral component longitudinal axis was measured in degrees and defined as neutral if the value fell within ±5° of the humeral axis. Angle values >5° and < 5 ° were defined as valgus and varus, respectively. The filling-ratio of the implant within the humeral shaft was measured at the level of the metaphysis (FRmet) and diaphysis (FRdia). Measurements were conducted by two independent examiners (SA and TW). To test for conformity of observers, the intraclass correlation coefficient (ICC) was calculated. The inter- and intra-observer reliability was excellent (ICC = 0.965, 95% confidence interval [CI], 0.911– 0.986). The average difference between the humeral shaft axis and the humeral component longitudinal axis was 3.8° ± 2.8° (range, 0.2° – 13.2°) corresponding to a true mean N-S angle of 149° ± 3° in valgus. Stem axis was neutral in 70% (n=90) of implants. Of the 34 malaligned implants, 82% (n=28) were in valgus (mean N-S angle 153° ± 2°) and 18% (n=6) in varus position (mean N-S angle 139° ± 1°). The average FRmet and FRdiawere 0.68 ± 0.11 and 0.72 ± 0.11, respectively. No association was found between stem diameter and filling ratios (FRmet, FRdia) or cortical contact with the stem (r = 0.39). Operative technique and implant design affect the ultimate positioning of the implant in the proximal humerus. This study has shown, that in uncemented short stem implants, neutral axial alignment was achieved in 70% of cases, while the majority of malaligned humeral components (86%) were implanted in valgus, corresponding to a greater than 145° neck shaft angle of the implant. It is important for surgeons to understand that axial malalignment of a short stem implant does influence the true neck shaft angle


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 9 - 9
1 Feb 2020
Vendittoli P Lavigne M Pellei K Desmeules F Masse V Fortier L
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INTRODUCTION. In recent years, there has been a shift toward outpatient and short-stay protocols for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). We developed a peri-operative THA and TKA short stay protocol following the Enhance Recovery After Surgery principles (ERAS), aiming at both optimizing patients’ outcomes and reducing the hospital length of stay. The objective of this study was to evaluate the implementation of our ERAS short-stay protocol. We hypothesized that our ERAS THA and TKA short-stay protocol would result in a lower complication rate, shorter hospital length of stay and reduced direct health care costs compared to our standard procedure. METHODS. We compared the complications rated according to Clavien-Dindo scale, hospital length of stay and costs of the episode of care between a prospective cohort of 120 ERAS short-stay THA or TKA and a matched historical control group of 150 THA or TKA. RESULTS. Significantly lower rate of Grade 1 and 2 complications in the ERAS short-stay group compared with the standard group (mean 0.8 vs 3.0, p<0.001). Postoperative complications that were experienced by significantly more patients in the control group included pain (67% vs 13%, p<0.001), nausea (42% vs 12%, p<0.001), vomiting (25% vs 0.9%, p<0.001), dizziness (15% vs 4%, p=0.006), headache (4% vs 0%, p=0.04), constipation (8% vs 0%, p=0.002), hypotension (26% vs 11%, p=0.003), anemia (8% vs 0%, p=0.002), oedema of the operated leg (9% vs 1%, p=0.005), persistent lameness (4% vs 0%, p=0.04), urinary retention (13% vs 4%, p=0.006) and anemia requiring blood or iron transfusion (8% vs 0%, p=0.002). No difference was found between the 2 groups for Grade 3, 4, or 5 complications. The mean hospital length of stay for the ERAS short-stay group decreased by 2.8 days for the THAs (0.1 vs 2.9 days, p bellow 0.001) and 3.9 days for the TKAs (1.0 vs 4.9 days, p<0.001). The mean estimated direct health care costs reduction with the ERAS short-stay protocol was 1489% per THA and 4206% per TKA. DISCUSSION AND CONCLUSION. Shorter hospitalization time after THA and TKA is associated with lower risk of nosocomial infections and adverse events related to reduced mobilization such as venous thromboembolism, pulmonary atelectasis, and constipation. In addition, it increases bed availability in a restricted environment and is very favorable economically for the care provider. Multiple strategies have been described to reduce hospital length of stay. One attractive option is to follow the ERAS principles to improve patient experience to a level where they will feel confident to leave for home earlier. Implementation of a ERAS short-stay protocol for patients undergoing THA or TKA at our institution resulted not only in reduced hospital length of stay, but also in improved patient care and reduced direct health care costs


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_6 | Pages 16 - 16
1 May 2019
Matharu G Berryman F Dunlop D Revell M Judge A Murray D Pandit H
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Introduction. We investigated predictors of poor outcomes following metal-on-metal hip arthroplasty (MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD), to help inform the revision threshold and type of reconstruction. Patients and Methods. A retrospective cohort study was performed involving 346 MoMHAs revised for histologically confirmed ARMD at two specialist centres (245=hip resurfacing, 101=total hip arthroplasty). Numerous preoperative (blood metal ions and imaging) and intraoperative (findings, and components removed/implanted) factors were used to predict poor outcomes. Poor outcomes were postoperative complications (including re-revisions), 90-day mortality, and poor Oxford Hip Scores (<27/48). Multivariable logistic regression models for predicting poor outcomes were developed using stepwise selection methods. Results. Cumulative implant survival rate seven-years after ARMD revision was 87.0% (95% CI=81.0%-91.2%). Poor outcomes occurred in 39% (n=135). Shorter time (under four-years) from primary to revision surgery (odds ratio (OR)=2.12, CI=1.00–4.46) was the only preoperative predictor of poor outcomes. Pre-revision metal ions and imaging did not influence outcomes. Single-component revisions increased the risk of poor outcomes (acetabular or femoral vs. all component revisions; OR=2.99, CI=1.50–5.97). Intraoperative factors reducing the risk of poor outcomes included the posterior approach (OR=0.22, CI=0.10–0.49), revision head sizes ≥36mm (vs. <36mm: OR=0.37, CI=0.18–0.77), ceramic-on-polyethylene (OR vs. ceramic-on-ceramic=0.30, CI=0.14–0.66) and metal-on-polyethylene revision bearings (OR vs. ceramic-on-ceramic=0.37, CI=0.17–0.83). Discussion. This large cohort study demonstrated 39% of patients experience poor outcomes following MoMHA revision for ARMD. This information will help surgeons when counselling patient's pre-revision about the expected prognosis. No threshold exists for recommending ARMD revision, therefore surgeons must make decisions on an individual case basis. However, surgeons can make intraoperative decisions that influence outcomes following ARMD revision. Conclusion. We recommend optimal outcomes following ARMD revision may be achieved if surgeons use the posterior approach, revise all MoMHA components, and use ≥36mm ceramic-on-polyethylene or metal-on-polyethylene articulations


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 53 - 53
1 Apr 2018
Herteleer M Quintens L Carrette Y Vancleef S Vander Sloten J Hoekstra H
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Purpose. Addressing posterior tibial plateau fractures is increasingly recognized as an important prognostic factor for functional outcome. The treatment of posterior tibial plateau fractures is rather demanding and the implants are still standard, off-the-shelf implants. This emphasizes the need for a more thorough morphological study of the posterior tibial plateau, in order to treat these posterior fractures more adequately. We aimed to demonstrate anatomical variations of the tibia in order to develop better implants. Method. After approval of the ethical committee 22 historically available CT scans of intact left tibia”s were segmented using Mimics (Materialise, Belgium). In order to perform principal component analysis, corresponding meshes are necessary. Mesh correspondence was achieved by deforming one selected source tibia to every other target tibia, through non rigid registration. The non-rigid registration algorithm was based on the algorithm described by Amberg et al (ref). After performing the non-rigid registration, principal component analysis was performed in Matlab (Mathworks, USA). Results. The first 3 components account for 98,1% of the anatomical shape variation of the tibia. The first principal component accounts for 95,4, the second accounts for 1,6% and the third component accounts for the remaining 1,1% of variation. In the first principal component the most marked variation was the length and the shaft width. Shorter tibia”s have a steeper and more angled posterior medial and lateral plateau as where longer tibia”s have a more rounded posterior tibia plateau. On the distal end, the tip of the medial malleolus is more prominent in shorter tibia”s than in longer tibia”s. The orientation of the tibiofibular joint is directed more posteriorly in larger tibias where it is orientated more laterally in smaller tibia”s. The slope of the medial and lateral tibia plateau is not related to the length or width of the plateau. The second principal component shows a relationship between a valgus shaped tibia shaft and its relation to a relatively smaller medial plateau”s compared with straight tibia”s of the same length. Valgus shaped, small tibia shafts have more posteriorly tilted lateral plateau”s compared with straight, broad shafted tibias. The third principal component shows that an angular shaped posterior tibia plateau is related to a more increased anterior bowing. The increase in the posterior tilt is mostly marked in the medial tibia plateau. Conclusion. The majority of tibia shape variations is directly related to the length of the shaft. The clinically known varus and valgus deformations represent only a small percentage of the total variation. Nevertheless, their variation within the second component is large and has a direct relation to the morphology of the tibia plateau. This data coud furthermore be used to improve implant design


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_4 | Pages 141 - 141
1 Jan 2016
Yang C
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Total knee replacement is a standard procedure for the end-staged knee joints. The main concerns at the perioperative period are infection prophylaxis, pain control, and blood loss management. Several interventions are designed to decrease the blood loss during and after the operation of total knee arthroplasty. In the recent meta-analysis showed that early tourniquet release of the tourniquet for hemostasis increased the total measured blood loss with primary TKR about 228.7 ml. So, Intra-operative blood loss for hemostasis can be saved by not to release the tourniquet after implants fixation, irrigation, closure of the wound and the application of compression dressing. Our study showed that most of the post-operative blood loss was collected during the first few postoperative hours: 37% in the first 2 hours and 55% in the first 4 hours and 82.1% in the first 24 hours. So, clamping the drainage for the first 4 postoperative hours would reduce blood loss after TKA (518 v.s. 843 mL). The fall in hemoglobin and Hct are also of significant difference (1.64 vs. 2.09 for Hb; 5.18 vs.7.69 for Hct). Appropriate clamping for an optimal time may be the most economical and simple, and the benefits of clamping also appear to outweigh its potential risks. NO DRAIN at all is able to reduce the post-operative blood loss. Our study showed that the decrease of postoperative hemoglobin was significantly less than that in no-drain group (1.45±0.72 vs 1.8±0.91). Shorter hospital stay was achieved in the no-drain group (8.3 ± 2.6 vs 10.7±3.2 days). All patients achieved good range of motion (flexion: 0 to >90 degree)by the five days after operation and no prosthetic infection was noted during follow-up. Thus, the routine use of closed suction drains for elective minimal-invasive total knee arthroplasty is not recommended