Acetabular Reaming Research Articles

Physical and mental demand during direct anterior total hip arthroplasty: Comparison of robotic-assisted and conventional techniques

IntroductionThe adoption of new techniques, such as the direct anterior (DA) approach, and technologies, such as robotic assistance, in total hip arthroplasty (THA) has the potential to alleviate the intraoperative physical and mental demand that surgeons experience. Therefore, the aim of this study is to compare the physical and mental demand of surgeons performing conventional DA THA with fluoroscopy and robotic-assisted DA THA without fluoroscopy. MethodsTwo orthopaedic surgeons completed bilateral DA THA's on six cadaveric specimens. To assess physical demand, heart rates (HR), respirations, HR variability (stress), calories burned, and sweat loss were recorded using smartwatches. Surgeons completed a modified SURG-TLX questionnaire to assess physical and mental demand. Data were pooled together and two-sample t-tests were performed. ResultsPhysical and mental demand metrics such as maximum HR, maximum stress, mean caloric expenditure and sweat loss were lower in robotic-assisted DA THA without fluoroscopy. Robotic-assisted THA was associated with a decreased percentage change for both the overall procedure and all surgical steps. Robotic-assisted THA also resulted in a significant difference in percentage change for maximum HR during acetabular reaming.Via questionnaire results, surgeons reported that robotic-assisted DA THA was significantly less physically and mentally demanding compared to conventional DA THA for the overall procedure and acetabular reaming. DiscussionIt is important to understand how robotic-assisted THA impacts the health of the surgeons using them. Robotic-assisted DA THA without fluoroscopy resulted in less physical and mental demand for orthopaedic surgeons for the overall procedure and individual surgical steps.

Long-Term Outcomes of Cementless Bipolar Hemiarthroplasty in Young Patients With Osteonecrosis of the Femoral Head: The Impact of Implant Improvements and Preoperative Stage.

Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH. Methods The records of consecutive patients with ONFH who underwent cementless BHA were retrospectively reviewed. Patients aged ≥60 years, with <10 years of follow-up, or who underwent acetabular reaming during surgery were excluded. Radiographical and clinical outcomes of patients who received first-generation BHAs and new-generation BHAs (developed after 1998) were compared by stratifying based on preoperative stage 2/3A and 3B/4, according to the Japanese Investigation Committee classification. Results Overall, 50 hips from 39 patients (mean age: 44.6 years; 64% male) with an average follow-up of 18.6 years were included. The frequency of advanced-stage patients was significantly higher in the first-generation BHA group than in the new-generation group. Regarding postoperative outcomes, the first-generation BHA group had higher acetabular erosion grades (p<0.001) and more femoral component loosening than those in the new-generation group (p<0.001). Revisions were performed in eight hips (seven in the first-generation and one in the new-generation BHA groups, p<0.001). In the new-generation BHA group, there were no significant differences in patient background between stage 2/3A and 3B/4 groups, and only one case in the stage 3B/4 group required revision. In the new-generation group, the grade of acetabular erosion was significantly higher for stage 3B/4 than stage 2/3A (p<0.001); other radiographical and clinical outcomes did not differ significantly between stages. Conclusion New-generation BHAs have significantly better implant survival rates for early-stage ONFH than those of first-generation BHAs. These findings indicate that BHA is an acceptable treatment option for early-stage ONFH in young patients.

Acetabular cup size trends in total hip arthroplasty.

Total hip arthroplasty (THA) is a common procedure for end stage osteoarthritis. The learning curve for THA is complex and challenging. One of the most difficult skills to master is acetabular reaming. We wish to identify if experience in arthroplasty leads to preservation of more bone stock. To investigate if increasing surgeon experience will predict an ever decreasing acetabular cup size. A retrospective case series of four attending orthopaedic surgeons was completed. All uncemented elective total hip arthroplasties since appointment were selected for inclusion. The size of acetabular cup used was noted and logistic regression was used to identify if a trend to smaller cups existed. A total of 1614 subjects were included with a mean age of 64 years. Overall cups were on average 0.18mm smaller per year (95% confidence interval -0.25 to -0.11, P < 0.001). Individual surgeon trends showed cup sizes to decrease 0.27 mm/year for surgeon A, 0.02 mm/year for surgeon B, 0.15 mm/year for surgeon C and 0.29 mm/year for surgeon D. Three of the four surgeons had a more pronounced trend to smaller cups for male subjects than their female counterparts. We found increasing surgeon experience to be associated with an ever-decreasing acetabular cup size. Smaller acetabular cup size may act as a surrogate marker of surgical proficiency by virtue of decreased acetabular reaming.

Does Body Mass Index (BMI) Affect the Reconstruction of Biomechanical Parameters in Patients Undergoing Total Hip Replacement (THR) through the Direct Anterior Approach (DAA)?

Direct anterior approach total hip replacement (DAA-THR) is gaining increased interest due to its tissue-sparing nature and rapid recovery. Obesity has been shown to be a significant parameter influencing cup positioning in DAA-THR. It was the intention of this retrospective study to examine how obesity would influence the restoration of native hip biomechanical parameters during DAA-THR. A total of 74 patients from a high-volume university orthopedic center after unilateral DAA-THA were included. Patients were retrospectively allocated to a study group (BMI > 30 kg/m2) and a control group (BMI < 30 kg/m2). Furthermore, propensity-score matching for baseline parameters was performed, leaving 30 patients in each group. Biomechanical parameters of the hip (i.e., femoral offset (FO), abductor lever arm (ABL), acetabular offset (AO), center of rotation (COR), stem alignment (SA), body weight lever arm (BWL), cup inclination (CI), and leg length discrepancy (LLD) were evaluated on standardized plain radiographs, and parameters were compared to the native contralateral hip. Mean BMI in the study group was 35.07 ± 5.13 kg/m2 and 25.43 ± 2.64 kg/m2 in the control group. There was a significant decrease of the ABL only in the study cohort (p = 0.01). CI and SA did not differ between both cohorts. FO was slightly increased compared to the native hip in both groups. There was a marginally higher but non-significant proportion of improper FO restoration in the study group (19 vs. 16 patients, p = 0.60). Obesity, as quantified by BMI, only has a limited impact on the adequate reconstruction of native biomechanical parameters of the hip during DAA-THR. ABL was the only parameter to be significantly decreased in the overweight patients after DAA-THR. Therefore, special care should be taken on proper acetabular reaming and consequent seating of the cup in the obese patient to avoid excessive lateral positioning.

Enhancing acetabular reaming accuracy: optimal techniques and a novel reamer design

IntroductionSuccessful press-fit implantation relies on an accurately reamed bone cavity. Inaccurate reaming can lead to a suboptimal press-fit risking fracture and cup deformation or excessive micromotion and loosening. Several factors may impact reaming accuracy including the reamer design, the surgeon’s technique and the bone quality. The aim of this study is to investigate the accuracy of reaming techniques and the accuracy of a novel reamer design.MethodsEighty composite bone models, half high density and half low density, were reamed with either a conventional or an additively manufactured reamer with a novel design employing either a straight or ‘whirlwind’ reaming technique. Reamed cavities were scanned using a 3D laser scanner and the median difference between achieved and expected diameters compared.ResultsThe novel reamer design was more accurate than the unused conventional reamer, using both whirlwind (0.1 mm (IQR 0–0.2) vs. 0.3 mm (IQR 0.3–0.4); p < 0.001) and straight techniques (0.3 mm (IQR 0.1–1.0) vs. 1.2 mm (IQR 1–1.6); p = 0.001). Whirlwind reaming was more accurate than straight reaming using both conventional (0.3 mm (IQR 0.3–0.4) vs. 1.2 mm (IQR 1–1.6); p < 0.0001) and single use reamers (0.1 mm (IQR 0–0.2) vs. 0.3 mm (IQR 0.1–1.0); p = 0.007). Reaming errors were higher in low-density bone compared to high-density bone, for both reamer types and reaming techniques tested (0.6 mm (IQR 0.3–1.5) vs. 0.3 mm (IQR 0.1–0.8); p = 0.005).ConclusionWe present a novel reamer design that demonstrates superior accuracy to conventional reamers in achieving the desired reaming diameter. Improved reaming accuracy was also demonstrated using both devices and in both bone models, using a ‘whirlwind’ technique. We recommend the use of this novel reamer design employing a ‘whirlwind’ technique to optimize reaming accuracy. Particular attention should be paid toward patients with lower bone quality which may be more susceptible to higher inaccuracies.

The direct anterior approach for conversion to total hip arthroplasty after acetabular fixation is safe and effective

IntroductionTotal Hip Arthroplasty (THA) after prior acetabular fracture repair is known to be demanding as studies have shown inferior implant survival rates and higher infection rates for these procedures. The direct anterior (DA) approach might help mitigate some of these risks by utilizing a new surgical tissue plane. However, potential criticisms of the DA approach for these surgeries include the inability to access previous acetabular implants or heterotopic ossification (HO) if they were to inhibit implant placement. The goals of this study are to analyze the efficacy of the DA approach for conversion to hip arthroplasty surgery after previous acetabular fixation. MethodsAfter reviewing all records at our institution using current procedural terminology codes, we isolated patients with previous acetabular repair who underwent conversion to THA through the DA approach. Patient records were reviewed, and patients were contacted to obtain Harris Hip Scores. Results23 patients (16 males and 7 females) were found with a mean follow-up time of 46 months (range 16–156 months). The mean age was 50 (range 28 – 83) and mean BMI was 28.5 (range 15.2 – 39.2). The average blood loss was 400 ml (range 200 – 900). The average operative time was 140 min (range 85–200 min). In 7 cases (32%) implants were encountered during acetabular reaming but the implants were either removed entirely or removed partially with a burr so that the acetabular cup could be positioned within acceptable parameters. In 2 cases pre-operative HO was encountered and was resected. The average Harris Hip Score at final follow-up was 92 (range 75 – 100). There were no deep infections and no neurovascular injuries encountered. 2 patients (9%) underwent revision surgery for aseptic femoral stem loosening. There was 1 anterior dislocation (4.5%) at 3 days post-operatively that was successfully treated with closed reduction and maintenance of hip precautions. Otherwise, the remaining 19 (86%) patients went on to uncomplicated recovery. ConclusionThis is the largest known cohort analyzing the DA approach for conversion to hip arthroplasty after previous acetabular fixation. Overall, we demonstrate that the DAA is safe for conversion THA after acetabular fixation.

HOW MUCH CAN A SURGEON TRUST A ROBOT FOR HIP ARTHROPLASTY?

The variables involved in a robotic THA can exceed 52: many parameters as pelvic orientation with CT scan, templating, offset, and leg-length, acetabular reaming, femoral osteotomy, mapping the anatomy; predefining safe zones, robotic execution, femoral head size, thickness of PE etc. with several variables for each parameter, with a total number of variables exceeding 52. This familiar number is the number of cards in a standard deck. The number of possible combinations (factorial 52! = 10^67) to shuffle the cards (and may be to perform a THA) is greater than the number of atoms on earth! Thinking that artificial intelligence and robotics can solve these problems, some surgeons and implant manufacturers have turned to artificial intelligence and robotics.We asked two questions:1) can robot with artificial intelligence really process 52 variables that represent 10^67 combinations? 2) the safety of the technology was ascertained by interrogating Food and Drug Administration (FDA) database about software-related recalls in computer-assisted and robotic arthroplasty [1], between 2017 and 2022.1)The best computers can only calculate around 100 thousand billion combinations (10^14), and with difficulty: it takes more than 100 days to arrive at this number of digits (10^14) after the decimal point for the number π (pi). We can, therefore, expect the robot to be imperfect.2)For the FDA software-related recalls, 4634 units were involved. The FDA determined root causes were: software design (66.6%), design change (22.2%), manufacturing deployment (5.6%), design manufacturing process (5.6%). Among the manufacturers’ reasons for recalls, a specific error was declared in 88.9%. a coding error in 43.8%. 94.4% software-related recalls were classified as class 2. Return of the device was the main action taken by firms (44.4%), followed by software update (38.9%).3)In the same period, no robot complained about its surgeon!Hip surgeon is as intelligent as a robot and almost twice as safe.

A NEW LESS INVASIVE HIP APPROACH

This technique is a novel superior based muscle sparing approach. Acetabular reaming in all hip approaches requires femoral retraction. This technique is performed through a hole in the lateral femoral cortex without the need to retract the femur.A 5 mm hole is drilled in the lateral femur using a jig attached to the broach handle, similar to a femoral nail. Specialised instruments have been developed, including a broach with a hole going through it at the angle of the neck of the prosthesis, to allow the rotation of the reaming rod whilst protecting the femur. A special C-arm is used to push on the reaming basket. The angle of the acetabulum is directly related to the position of the broach inside the femoral canal and the position of the leg. A specialised instrument allows changing of offset and length without dislocating the hip during trialling.Some instrumentation has been used in surgery but ongoing cadaver work is being performed for proof of concept. The ability to ream through the femur has been proven during surgery. The potential risk to the bone has been assessed using finite analysis as minimal. The stress levels for any diameter maintained within a safety factor &gt;4 compared to the ultimate tensile strength of cortical bone.The described technique allows for transfemoral acetabular reaming without retraction of the femur. It is minimally invasive and simple, requiring minimal assistance. We are incorporating use with a universal robot system as well as developing an electromagnetic navigation system. Assessment of the accuracy of these significantly cheaper systems is ongoing but promising.This approach is as minimally invasive as is possible, safe, requires minimal assistance and has a number of other potential advantages with addition of other new navigation and simple robotic attachments.

A Reamer by Another Number: What Do They Actually Measure?

Acetabular reamers are a mainstay in the preparation of the acetabulum in total hip arthroplasty. Many surgeons, however, have noticed a discrepancy in the preparation of the socket and the reported size of reamers during this crucial phase of the procedure. A cross-sectional study performed by measuring a variety of sets of acetabular reamers was performed. The results showed that 17 of 21 sizes (81%) measured at least 2mm less than their reported size. Given that these differences beget unintended consequences, the industry may consider replacing or sharpening reamers already in use or even switching to a single-use reamer model.

Revision Total Hip Arthroplasty with Severe Acetabular Defect: A Preliminary Exploration and Attempt of Robotic‐Assisted Technology

BackgroundRobotic‐assisted technology may be useful in hip revision cases with acetabular defects. However, data on the use of robotic‐assisted technology for such complex diseases is lacking.Case PresentationThis case study described the adoption of MAKO robotic‐assisted treatment of revision total hip arthroplasty (THA) combined with severe acetabular defect (Paprosky type IIIB). Robotic‐assisted technology accurately achieved preoperative planning; the acetabular component and augment were placed in the original position and angle as planned. Robotic‐assisted acetabular reaming was successful in a single pass, preserving the remaining acetabular bone mass very well with no procedure‐related complications. The Harris Hip Score (HHS) at 6 months postoperatively was 84 and the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index was 24.ConclusionRobotic‐assisted technology can help in the accurate reconstruction of acetabular defect in complex hip revision surgery.

Acetabular Reaming Is a Reliable Model to Produce and Characterize Periarticular Heterotopic Ossification of the Hip.

Heterotopic ossification (HO) is a pathologic process characterized by the formation of bone tissue in extraskeletal locations. The hip is a common location of HO, especially as a complication of arthroplasty. Here, we devise a first-of-its-kind mouse model of post-surgical hip HO and validate expected cell sources of HO using several HO progenitor cell reporter lines. To induce HO, an anterolateral surgical approach to the hip was used, followed by disclocation and acetabular reaming. Animals were analyzed with high-resolution roentgenograms and micro-computed tomography, conventional histology, immunohistochemistry, and assessments of fluorescent reporter activity. All the treated animals’ developed periarticular HO with an anatomical distribution similar to human patients after arthroplasty. Heterotopic bone was found in periosteal, inter/intramuscular, and intracapsular locations. Further, the use of either PDGFRα or scleraxis (Scx) reporter mice demonstrated that both cell types gave rise to periarticular HO in this model. In summary, acetabular reaming reproducibly induces periarticular HO in the mouse reproducing human disease, and with defined mesenchymal cellular contributors similar to other experimental HO models. This protocol may be used in the future for further detailing of the cellular and molecular mediators of post-surgical HO, as well as the screening of new therapies.

Anatomic placement of the acetabular implant in cementless total hip arthroplasty does not adversely affect the implant survival and patient satisfaction

ObjectiveThis study aimed to evaluate if the acetabulum's conservative reaming with preservation of the medial acetabular bone and anatomic placement of the acetabular implant in cementless total hip arthroplasty (THA) has any adverse effect on the radiological outcome, long term implant survival and patient satisfaction. Methods106 consecutive patients were identified from a single surgeon practice who underwent cementless THA from 2005 to 2010. Twenty-one were lost to follow up, and five patients died unrelated to THA. Eighty patients were available for the study. The mean follow-up was 8.6 years (range 5.7–11.6). The mean age was 61.9 years. Immediate pre- and postoperative radiographs were reviewed to calculate combined offset (Acetabular offset – AO, plus Femoral offset – FO). Implant failure, aseptic loosening, revision surgery, patient satisfaction and complications were assessed on long-term follow-up. ResultsAcetabular component survival was 100% with no aseptic failure. None of the patients had revision surgery for any cause. The mean difference in the acetabular offset and combined offset postoperatively was within 3 mm. One patient had a dislocation, and one had a prosthetic joint infection (PJI). 95% of the patients in this series would recommend the hip replacement procedure to others, with a mean satisfaction score of 8.7 (range; 1–10). ConclusionConservative acetabular reaming with preservation of medial acetabulum bone with the anatomic placement of the acetabular implant in cementless THA is safe with no adverse effects on implant survival and patient satisfaction. It offers the advantage of preserving the patient's bone stock, which would potentially be of significant advantage to the patient and the surgeon in case of revision arthroplasty.

Three-dimensional morphological analysis of true acetabulum in Crowe type IV hip dysplasia via standard-sized cup-simulated implantation.

Acetabular reconstruction in Crowe type IV developmental dysplasia of the hip (DDH) can be a challenging procedure for surgeons. A high risk of acetabular revision has been reported to be associated with extremely small acetabular prostheses. However, to our knowledge, quantitative morphological and coverage evaluations of the true acetabulum in Crowe IV hips have been infrequently conducted. Useful bony landmarks for acetabular reconstruction can also facilitate satisfactory intraoperative implantation. The aim of the present study was to investigate the anatomical size, orientation angles, and 2/3-dimensional (2D/3D) coverage parameters of the true acetabulum in Crowe IV hips; evaluate the feasibility of standard cup (>44 mm) implantation at the true acetabulum in Crowe IV hips; and identify the optimal position and useful bony landmarks of the acetabular reaming center in Crowe IV hips. A total of 42 Crowe IV hips in 37 patients and 36 normal hips were included in this study. Based on pelvic 3D computed tomography (CT) reconstruction, anatomical size and integral volume of the true acetabulum were measured quantitatively. Through standard-size cup-simulated implantation, morphological assessments of the true acetabulum included Cup-CE, Cup-Sharp, acetabular anteversion angle, and thickness of the medial wall. Acetabular sector angles (ASAs) and the component coverage ratio were measured to provide coverage indices. Acetabular reconstruction was also performed at different vertical levels to measure medial bone stock and 3D component coverage. Bony landmarks for optimal component center location were also determined. The anatomic shape and volume of the acetabular triangle were significantly smaller in Crowe IV hips. Compared with the control group, the dysplastic acetabulum was more anteverted and abductive, with a thicker medial wall. According to the true acetabulum, bone stock was relatively sufficient in the posterior direction and prominently deficient in the anterosuperior and superior direction. The average 3D component coverage reached 79.89% by standard-sized cup implantation, with the most satisfactory coverage achieved at the true acetabulum (at the level of 13.32 mm above the transverse acetabular ligament). Regarding the component opening plane, the optimal component center was located at the midpoint between the superolateral and posteroinferior points of the true acetabulum. The most satisfactory coverage was achieved at the level of the true acetabulum, of which the most prominent deficiency was mainly located in the anterosuperior and superior directions. The optimal component center was determined to be the midpoint between the superolateral and posteroinferior points of the true acetabulum.

Learning curve and short-term clinical outcomes of Mako robotic-assisted direct anterior approach total hip arthroplasty

Objective: To explore the learning curve and short-term clinical outcomes of Mako robotic-assisted direct anterior approach total hip arthroplasty (THA). Methods: The preoperative basic data, surgical information and postoperative rehabilitation of 50 patients who underwent Mako robotic-assisted THA for hip diseases in Department of Orthopedic Surgery of the 6th People's Hospital Affiliated to Shanghai Jiao Tong University from December 2018 to December 2020 were analyzed retrospectively, included operation time, intraoperative blood loss, postoperative complications, postoperative imaging parameters (abduction angle, anteversion angle, lower limb length difference, eccentricity difference) and postoperative hip joint Harris score (hip Harris score, HHS). There were 16 males and 34 females, with a mean age of 50-79(67±10) years. The postoperative clinical results of Mako robotic-assisted total hip arthroplasty was analyzed. A cumulative sum analysis (CUSUM) was performed on the operation time (OT). The CUSUM learning curve was modeled by curve fitting and R² was used to testify the goodness. The different phase of the learning curve was compared with several observation indicators. Results: All patients were followed up for more than 6 months. Two patients had poor wound healing and 5 patients had symptoms of lateral femoral cutaneous nerve injury, which disappeared within 1-2 months. No serious complications such as dislocation, aseptic loosening, periprosthetic infection or revision occurred in all the patients. The average operation time was (81±16) min, and the intraoperative blood loss was (456±84) ml. The average Harris hip score at the last follow-up was 88.6±2.5. The radiological evaluation showed that the positions of the acetabular cups were all in the Lewinnnek safety zone; the limb length discrepancy was (0.15±0.50) cm, the offset was (-0.11±0.72) cm. The OT decreased with the accumulation of the cases. The CUSUM learning curve was best modeled as cubic curve,the fitting curve reached the top at the 19th case. As a cut-off point, the 19th point divided the learing curve into two phases. There were statistical differences in OT, pelvic array installation time, acetabular registration time, acetabular reaming time (all P<0.05), but there was no significant differences in Harris hip score, acetabular prosthesis anteversion angle and abduction angle between the two groups (all P>0.05). Conclusions: The learning curve of Mako robot-assisted DAA-THA is about 19 cases. Mako robot-assisted DAA-THA can ensure the accuracy of prosthetic placement and the safety of the operation during the learning curve, and the short-term clinical results after surgery is excellent.

Is Robotic Arm Assisted Total Hip Arthroplasty More Bone Preserving than Conventional Hip Replacements and Hip Resurfacing?

Background: Total hip arthroplasty (THA) is a common procedure that is increasingly being performed in younger patients. Deep acetabular reaming will result in more bone loss and the need for large acetabular components to be implanted. It can also lead to impingement, loosening, an altered center of rotation, and intraoperative periprosthetic fracture. The purpose of this study is to determine whether the single ream, robotic arm-assisted (RAA) THA can preserve a greater volume of bone stock compared to conventional hip replacement and resurfacing. Methods: We prospectively recruited 69 patients who had undergone primary THA using the Stryker Trident Acetabular System® in combination with the Stryker RAA System (MAKO)® and compared their mean reaming weight (g) with that of conventional hip replacement and resurfacing, as measured by Brennan et al. Comparison of acetabular reaming during hip resurfacing versus uncemented THA (J Orthop Surg. 2009; 17(1): 42-46). Results: The mean reaming weight using the MAKO system was 9.08 g, which was 29% less than the reaming weight using uncemented THA and hip resurfacing of 12.75 g. None of the acetabular cups required screw fixation. During the 35-month follow-up period, there were no complications related to cup placement or positioning. Conclusions: The use of RAA THA results in statistically significant preservation of acetabular bone compared to conventional hip replacement and resurfacing. This approach reflects the increased precision offered by RAA single reaming. Surgeons may consider utilizing RAA THA, particularly in younger patients, to better preserve bone stock as this could potentially impact future revision procedures.

Does total hip arthroplasty with high hip centre in dysplasia compromise acetabular bone stock?

The placement of uncemented acetabular components during total hip arthroplasty (THA) in Crowe II and Crowe III dysplasia can be at the anatomic or high hip centre position. Using computerised tomography data, we simulated acetabular cup placement at the anatomic hip centre and the high hip centre positions to assess whether there is a difference between the 2 in terms of bone loss from acetabular reaming and in acetabular coverage by host bone. The study population included a consecutive cohort of 19 patients (22 hips) with Crowe II or III dysplasia. 3-dimensional models of the pelvis were created for each patient and digital templating was used to determine the anatomic and high hip centre positions. The coordinates of the digitally templated cup positions were fed into an image processing software to estimate the amount of bone reamed, the cup coverage by host bone and the elevation from tear drop. The mean volume of bone reamed was greater in the high hip centre position as compared to the anatomic position (27.3 ± 11. 4 cm3 vs. 19.4 ± 12.2 cm3, p < 0.0001). The coverage of the acetabular cup by host bone was greater in the high hip centre position (87.3 ± 5.9% vs. 68.3 ± 10%). The mean elevation in the high hip centre group was 13 mm with 3 hips having a breach of the medial wall. In Crowe II and III dysplasia, placement of acetabular cups at the anatomic hip centre better preserves bone stock as compared to high hip centre placement and should be preferred in young patients requiring THA.

Key performance and training parameters in primary total hip arthroplasty - an expert consensus using the Delphi technique.

Primary total hip arthroplasty (THA) is a commonly performed and successful operation which orthopaedic trainees must demonstrate competence in prior to completion of surgical training. An assessment of agreement between surgical trainers regarding the critical steps of a primary THA has never been undertaken. The aim of this study was to define and rank the key steps of a primary THA regards ease of teaching and their importance in achieving the best patient outcome. The Delphi technique with 3 iterative rounds was used to establish expert group consensus. The benchmark for consensus was set at an 80% agreement in any category for each step of a THR. The intra-class correlation coefficient (ICC) was used to report on the inter- and intra-rater reliabilities between and within participants responses respectively in rounds 2 and 3. 50 consultant orthopaedic hip surgeons completed round 2, and 28 completed round 3. Overall, 27 steps (54 parameters) were identified, with 16 parameters achieving consensus agreement for their impact on patient outcome, and 17 for ease of teaching. The inter-rater ICC for patient outcome parameters was 0.89 and 0.92 in rounds 2 and 3 respectively while for teaching parameters it was 0.82 and 0.73. 50% of surgeons agreed that acetabular reaming, assessing and accurately restoring leg length, and acetabular cup anteversion were the 3 most difficult steps to teach trainees, while 90% agreed these 3 steps were substantially important to patient outcome. Another 5 steps achieved consensus for their substantial impact on patient outcome but failed to achieve consensus for ease of teaching. The results of this expert consensus have produced a rank-order list of the key steps in primary THA, which may be used for orthopaedic curriculum development and guiding focused improvements for surgical training in primary THR including simulation.

TiN-Ag as an antimicrobial and wear resistant coating

Nosocomial infections are a major clinical concern, posing great risks for patients and rising costs for health services providers. This work aims at developing a hard, wear resistant coating, whose antimicrobial properties shall prevent the transmission of infections.TiN coatings deposited by Physical Vapour Deposition, PVD, with different Ag contents have been studied, especially in relation to the hardness and adhesion, their microstructure and morphology. The antimicrobial activity of the surfaces has been assessed against Staphylococcus epidermidis at different time frames, one of the most troublesome source of infections in trauma and orthopaedic surgeries. The electro-tribology properties of different silver contest have been studied. Finally, the coatings have been deposited on surgical acetabular reamers and wear resistance tests have been carried out against synthetic composite bone (simulating cortical and cancellous bone).Results have shown a good coating adhesion on stainless steel (both quantitatively in the scratch tests and qualitatively in the tests against synthetic composite bone), while the hardness decreased with higher Ag percentages. Furthermore, coatings exhibited antimicrobial activity against S.epidermidis, limited silver release, a remarkable wear resistance (vs. uncoated surgical acetabular reamers), while the electrical contact resistance provided valuable information about the evolution of friction and the status of the coating. Therefore TiN-Ag coatings present promising features for reducing the risk of infections, monitoring and extending cutting edge life and quality, and thus limiting damage to living tissues, e.g. necrosis.

Glenoid and acetabular reaming force varies in simulation between fellowship trained surgeons

BackgroundThe acquisition of surgical skills required to correctly perform orthopedic procedures varies among different institutions due to the diversity of training curriculums. With its technologic advances, surgical simulation can provide trainees with an accurate, safe, and standardized mean to practice procedures throughout their time in residency. The force utilized by a surgeon while reaming relies on prior experience and muscle memory developed throughout their career. The aim of the present study was to evaluate and compare the average force applied during reaming of an acetabulum vs. a glenoid by fellowship trained orthopedic surgeons in order to provide trainees a standard to use during simulation and in practice and to provide an understanding of the force differentials. MethodsA reaming simulator was created by installing a force transducer onto a reamer which allowed the testing of fellowship trained hip and shoulder orthopedic surgeons from the surrounding communities. Each surgeon was given 6 trials to determine the mean clinical force and their max effort force. Demographic information was surveyed for each participating surgeon to determine their level of experience and personal characteristics. Statistical analysis was performed using a Welch t test for scale variables and a Levene's F test to compare variances between groups via SPSS Statistics 24 software. ResultsA 61% greater mean clinical force was applied while simulating reaming of the acetabulum (90.12 N ± 30.12) than of the glenoid (55.91 N ± 25.65), t (184) = 8.0, P< .001. When shoulder (297.62 N ± 82.25) and hip surgeons (318.11 N ± 112.06) were asked to push the reamer at a maximal effort, there was no significant difference between the max effort force generated by the 2 groups (P = .16). For glenoid reaming, shoulder surgeons applied 19% of their max effort force while for acetabular reaming, hip surgeons applied 28% of their max force. ConclusionThe mean clinical force utilized to ream an acetabulum is greater than that of a glenoid by nearly twofold. Application of this knowledge can be translated into surgical simulation training for residents to help them develop the proper muscle memory for reaming in the 2 different clinical scenarios throughout residency. Reamers with an incorporated force transducer could provide surgeons, in real time, feedback on the force they apply to bone. With the advances in simulations, these tools can be optimized to give trainees tactile feedback when learning crucial steps of surgery. Level of evidenceClinical Science Study; Biomechanics

Variability of Cutting and Thermal Dynamics Between New and Used Acetabular Reamers During Total Hip Arthroplasty.

BackgroundAseptic loosening of the acetabular component remains one of the leading causes of early failure of total hip arthroplasty. Poor apposition of bone onto the implant surface can be due to inaccurate reaming and osteonecrosis of the acetabular bone due to the heat generated while reaming.MethodsNew and used acetabular reamers were tested on an MTS system using a clinically relevant force of 87.6 N. A thermal profile and depth achieved by the reamers were analyzed and compared between the 2 cohorts. Heat generated and force required for the community used reamers to achieve the same depth as the new reamers were subsequently analyzed.ResultsThe new reamers achieved a depth 3.4 mm deeper than the community reamers (P < .001). The new reamers generated 4.1°C less heat than the community reamers (P = .007) under the same force and time. When programmed to ream to the average depth of the new reamers, the community reamers generated 16.8°C more heat (P = .002) and required forces 95-318% greater than the 87.6 N force used by the new reamers.ConclusionsCommunity use of reamers will cause variations in depth of penetration and increased temperatures at a clinically generated force vs new reamers. When community reamers were forced to the same depths the new reamers achieved, a significantly greater amount of heat was generated, and an increased amount of time was needed, both of which are known risk factors for osteonecrosis.