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Bone & Joint Open
Vol. 2, Issue 3 | Pages 191 - 197
1 Mar 2021
Kazarian GS Barrack RL Barrack TN Lawrie CM Nunley RM

Aims

The purpose of this study was to compare the radiological outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA).

Methods

Postoperative radiological outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic centre were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiologically measured to identify outliers.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_10 | Pages 18 - 18
1 Oct 2020
Nunley RM Barrack RL Lawrie CM
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Introduction

Modular dual mobility (MDM) prostheses are increasingly utilized for total hip arthroplasty (THA) to mitigate the risk of postoperative instability in high risk patients. Short-term reports on clinical outcomes are favorable but there are few studies on young active patients. This study quantified proximal femoral stress shielding and metal ion release in MDM combined with modern cementless stem design in young active patients.

Methods

This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m2 and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. DEXA scans were performed at 6 weeks postoperatively as a baseline, then again at 6 months, 1 year, 2 years and 5 years postoperatively as were metal ions.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_9 | Pages 69 - 69
1 Oct 2020
Lawrie CM Barrack RL Nunley RM
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Introduction

Bone mineral density (BMD) is correlated with component migration and aseptic loosening after total knee arthroplasty (TKA). Older implant designs have demonstrated BMD loss up to 23% in the first 6 months after TKA, and continued to BMD decline at an average of 5% per year for as long as 2 years after TKA. The impact of component design and fixation method on BMD loss after TKA in modern implant designs has not been fully elucidated. The purpose of this study is to determine the effect of tibial tray thickness and fixation method (cemented versus cementless) on BMD loss patterns of the proximal tibia in two different modern TKA implant systems

Methods

A prospective, nonrandomized, single center study of patients undergoing primary TKA by one of two surgeons was performed with four study cohorts: cemented DePuy Attune, cementless DePuy Attune, cemented Stryker Triathlon, cementless Stryker Triathlon. Target sample size was 80, with 20 per cohort based on adhoc power analysis. Exclusion criteria included: age over 75, BMI >40, inflammatory arthritis, previous knee surgery involving the femur, tibia or tibial bone, and diagnosis of osteopenia/osteoporosis. Implant fixation type was based on surgeon intraoperative assessment of patient bone quality. Demographic data was collected preoperatively. Dual Energy X-ray Absorptiometry (DEXA) Bone Density Monitoring was performed at 6 weeks and one year postoperatively. Bone mineral density was calculated from the DEXA scans for 4 zones for the tibia relative to the keel or central peg: anterior, posterior, medial and lateral. Results were reported as BMD at 1 year postoperatively as a percentage of BMD at 6 weeks postoperatively.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_10 | Pages 54 - 54
1 Oct 2020
Freiman S Schwabe M Pashos G Barrack RL Nunley R Adelani M Pascual-Garrido C Clohisy J Lawrie C
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Introduction

The purpose of the study was to determine access to and, ability to use telemedicine technology in an adult hip and knee reconstruction patient population and we seek to understand these patients' perceived benefits, risks and preferences of telemedicine.

Methods

We performed a cross-sectional telephone administered survey on patients scheduled to undergo primary THA and TKA by one of six surgeons at a single academic institution between March 23 and June 2, 2020.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_9 | Pages 24 - 24
1 Oct 2020
Kazarian GS Barrack RL Barrack TN Lawrie CM Nunley RM
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Introduction

The purpose of this study was to compare the radiographic outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA).

Materials & Methods

Postoperative radiographic outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic center were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiographically measured to identify outliers. Clinical results at 4–6 weeks postoperative were compared to a control cohort of total knee arthroplasty (TKA) patients from our institution.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_11 | Pages 4 - 4
1 Oct 2019
Lawrie CM Okafor LC Kazarian GS Barrack TN Barrack RL Nunley RM
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Background

The purpose of this study was to assess the overall clinical and radiographic outcomes of unicompartmental knee arthroplasty (UKA) in the 2–10 year postoperative period. The secondary goal was to compare outcomes between fixed- (FB) and mobile-bearing (MB) implant designs.

Methods

We performed a retrospective analysis of 237 consecutive primary medial UKAs from a single academic center. All cases were performed by high-volume fellowship-trained arthroplasty surgeons, though UKA comprised <10% of their overall knee arthroplasty practice (<20 medial UKAs per surgeon per year). Clinical outcomes included the Oxford Knee Scores (OKS) and revision rates. Femoral and tibial coronal and sagittal angles (FCA, FSA, TCA, TSA) were radiographically measured. FCA (>±10º deviation from the neutral axis), FSA (>15º flexion), TCA (>±5º deviation from the neutral axis), and TSA (>±5º deviation from 7º) outliers were defined. Far outliers were defined as measurements that fell an additional >±2º outside of these ranges. Outcomes were compared between the FB and MB groups.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_11 | Pages 34 - 34
1 Oct 2019
Lawrie CM Jo S Barrack TN Barrack RL
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Introduction

Periprosthetic infection (PJI) after primary total knee arthroplasty (TKA) remains a challenging issue affecting 1–2% of cases. Locally delivered prophylactic antibiotics, including tobramycin or gentamicin mixed in polymethylmethacrylate (PMMA) bone cement and vancomycin powder, are increasingly used despite a lack of high quality evidence for either practice. In this study, we report the antibiotic susceptibility of organisms recovered in culture from patients with acute prosthetic joint infection after primary TKA to gentamicin, tobramycin and vancomycin.

Methods

Using a retrospective database of all primary TKA performed at a single institution between January, 1 2014 and July 1, 2018, we identified 18 cases of acute PJI after primary TKA, as defined by the Musculoskeletal Infection Society 2011 guidelines as less than 3 months from symptoms or index surgery to presentation. The use of antibiotic bone cement during the index procedure and time to surgical management of the infection were recorded. Fluid cultures and tissue cultures were obtained intraoperatively at the time of revision. The organisms from positive cultures underwent MIC testing to gentamicin, tobramycin and vancomycin using a gradient diffusion method (ETEST). MIC breakpoints for susceptibility were based on Clinical and Laboratory Standards Institute definitions.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_12 | Pages 23 - 23
1 Oct 2019
Lawrie CM Barrack TR Abu-Amer W Adelani MA Clohisy JC Barrack RL Nunley RM
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Introduction

The utility and yield of the current practice of routine screening of asymptomatic patients after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) is unclear. The purpose of this prospective survey study was to determine the utility of the routine on year follow up visit primary THA and TKA.

Methods

We prospectively enrolled all patients undergoing primary THA and TKA. At one-year follow-up, patients were asked to complete a survey that asked about satisfaction with the and if they thought the visit was worthwhile. Surgeons also completed a survey which asked if any intervention was done, if any problems were diagnosed/avoided, and if the visit was worthwhile. Data was analyzed and compared between patients and surgeons, and was also compared to the need for any additional interventions


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_12 | Pages 8 - 8
1 Oct 2019
Lawrie CM Schloemann D Kazarian GS Barrack TN Barrack RL
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Background

The aim of this study was to determine the change in standing pelvic sagittal alignment and associated impact on functional acetabular component position at follow-up after total hip arthroplasty (THA).

Patients and Methods

A retrospective review was performed on 91 consecutive patients who had undergone primary THA by a single surgeon via a posterior approach in the lateral decubitus position. Of these, 41 patients had high quality standing AP pelvis radiographs preoperatively, at six weeks postoperatively, and at one year postoperatively available for analysis. Pelvic ratio was defined as the ratio between the vertical distance from the inferior sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior SI joints. Apparent changes in the functional acetabular component position were determined from the change in pelvic ratio between the preoperative and one year postoperative standing AP pelvic radiograph. A change of at least five degrees was considered clinically meaningful.


The Bone & Joint Journal
Vol. 101-B, Issue 4 | Pages 365 - 371
1 Apr 2019
Nam D Salih R Nahhas CR Barrack RL Nunley RM

Aims

Modular dual mobility (DM) prostheses in which a cobalt-chromium liner is inserted into a titanium acetabular shell (vs a monoblock acetabular component) have the advantage of allowing supplementary screw fixation, but the potential for corrosion between the liner and acetabulum has raised concerns. While DM prostheses have shown improved stability in patients deemed ‘high-risk’ for dislocation undergoing total hip arthroplasty (THA), their performance in young, active patients has not been reported. This study’s purpose was to assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular DM acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design.

Patients and Methods

This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m2 and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (sd 6.5)) were enrolled. All patients had a minimum of two years’ clinical follow-up. Patient-reported outcome measures, whole blood metal ion levels (ug/l), and periprosthetic femoral BMD were measured at baseline, as well as at one and two years postoperatively. Power analysis indicated 40 patients necessary to demonstrate a five-fold increase in cobalt levels from baseline (alpha = 0.05, beta = 0.80). A mixed model with repeated measures was used for statistical analysis.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_12 | Pages 29 - 29
1 Oct 2018
Lawrie CM Schwabe M Pierce A Barrack RL
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Introduction

Cemented total knee arthroplasty (TKA) remains the gold standard with survivorship above 90% at greater than 10 years postoperatively. However, with younger, heavier, more active patients undergoing TKA at an increasing rate, cementless implants have the appeal of potential for improved implant fixation longevity and decreased rates of aseptic loosening. The cementless implants are more expensive than their cemented counterparts such that implant costs may create a barrier to utilization. However, such comparisons fail to consider the unavoidable additional costs of cementing, including the cost of operating room time, cement and cementing accessories. The purpose of this study is to compare the actual cost of cemented and cementless TKA.

Methods

The TKA cost calculation included the cost of operative time, implants, cement and cementing accessories. The difference in operative time between cemented and cementless TKA was determined from a previously published study of 100 TKAs performed using a cemented (55) or press fit (45) implant of the same design performed at a single institution by four fellowship trained arthroplasty surgeons. The decision to use cemented or cementless design in these patients was made based on patient bone quality intraoperatively. Operative time was compared between groups using a Student's two-tailed T-test. The cost of operating room time was based on estimates in the recent literature. The cost of cement and cementing accessories was estimated based on publically available market data. The cost of implants was estimated from institutional data for multiple companies.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_12 | Pages 19 - 19
1 Oct 2018
Kazarian GS Barrack TN Donaldson MJ Lawrie CM Miller GA Haddad FS Barrack RL
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Introduction

Implant malalignment is an important predictor of prosthetic failure following total knee arthroplasty (TKA). The purpose of this study was to determine the incidence of outliers for common alignment targets and the impact of surgeon volume and experience on the accuracy of implant alignment with current generation manual instrumentation.

Methods

This study was a retrospective, multi-center, radiographic analysis of 1675 consecutive primary uncomplicated TKAs from seven surgeons at three academic and state-funded centers in the US and UK. Surgeons were categorized as “high-volume” (≥50 TKAs/year) and “high-experience” (≥5 years post-fellowship). Femorotibial, tibial varus/valgus, and posterior tibial slope angles were digitally measured using postoperative radiographs. Femorotibial (<2° or >8° valgus), tibial (> ±3° deviation from the neutral axis), and tibial slope (<0° or >7° of flexion for cruciate retaining, <0° or >5° of flexion for posterior stabilized) angle outliers were identified. The proportion of outliers among surgeons in each subgroup was compared.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_13 | Pages 42 - 42
1 Oct 2018
Schloemann DT Edelstein AI Barrack RL
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Introduction

Malposition of the acetabular component in total hip arthroplasty (THA) is linked to multiple adverse outcomes. Changes in the sagittal plane position of the pelvis, owing both to patient positioning in the operating room and to altered spinopelvic alignment following surgery, potentially contribute to variation in component position. The dynamics of sagittal plane pelvic position before, during, and after THA have not been defined. We measured the differences in pelvic ratio, a measure of sagittal plane pelvic position, between preoperative, intraoperative, and postoperative anteroposterior (AP) radiographs of patients undergoing THA in the lateral decubitus position.

Methods

We retrospectively compared the radiographic pelvic ratio among 90 patients undergoing THA. AP radiographs were obtained in the standing position preoperatively and at 6 weeks after surgery; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post anesthesia care unit (PACU). Pelvic ratio was defined as the ratio between the vertical distance from the inferior sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior SI joints. Radlink software was used to determine the pelvic ratio on each radiograph. Changes in apparent cup position based on changes in pelvic ratio were calculated using data from the literature, and a change of at least 10 degrees in acetabular component position was defined as clinically meaningful. Analyses were performed using paired t-tests, with p<0.05 defined as significant.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_13 | Pages 11 - 11
1 Oct 2018
Nam D Salih R Riegler V Nunley RM Clohisy JC Lombardi AV Berend KR Barrack RL
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Introduction

Despite well-fixed implants, persistent pain following total hip arthroplasty (THA) remains a concern. Various surgical approaches have been advocated, yet whether patient-reported pain differs amongst techniques has not been investigated. This study's purposes were to determine differences in patient-reported pain based on surgical approach (direct anterior –DA versus posterolateral-PL) or PL approach incision length. Our hypothesis was that no differences in patient-reported pain would be present.

Methods

A retrospective, IRB-approved investigation from 2 centers was performed. 7 fellowship trained arthroplasty surgeons (3 DA, 3 PL, 1 both) enrolled patients undergoing primary THA for non-inflammatory arthritis. PL approach patients were categorized based on incision length (6–8cm, 8–12cm, 12–15cm). Exclusion criteria were a prior hip surgery, revision procedure, or limited postoperative mobility. All THAs were performed using a cementless titanium, proximally coated, tapered femoral stem and hemispherical acetabular component. All patients had a minimum of 1-year clinical follow-up with radiographically well-fixed components.

A pain-drawing questionnaire was administered in which patients identify the location and intensity of pain on an anatomic diagram. Independent Student's t-tests and Chi-square analyses were performed (p<0.05 = significant). Power analysis indicated 800 patients in each cohort would provide adequate power to detect a 4% difference in patient-reported pain (alpha = 0.05, beta = 0.80).


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 263 - 263
1 Jul 2011
Barrack RL Burnett RSJ Barnes CL Miller D Clohisy JC Maloney WJ
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Purpose: A study was undertaken to determine the current prevalence of revisions of total knee arthroplasty (TKA) following minimal incision surgery (MIS) and to compare revisions of MIS TKA procedures to revisions of TKA performed following a standard surgical approach.

Method: A consecutive series of revision TKA performed at three centers by five surgeons over a three year time period was reviewed. Revisions performed for infection and re-revisions were excluded. Review of clinical and radiographic data determined incision type, gender, age, time to revision, and primary diagnosis at time of revision.

Results: Two hundred and thirty-seven first time revision TKAs were performed of which 44 (18.6%) had been a MIS primary TKA and 193 (81.4%) had been a standard primary TKA. Patients with MIS were younger (62.1 years versus 66.2 years, p=.02). There was a trend towards a higher percentage of females in the MIS group (75% versus 63%), although this difference was not significant (p=0.12). Most striking was the difference in time to revision which was significantly shorter for the MIS group (14.8 months versus 80 months, p< .001). The MIS group was much more likely to fail at < 12 months (37% versus 5%, p< .001) and at < 24 months (81% versus 22%, p< .001).

Conclusion: MIS TKA accounted for a substantial percentage of revision TKA in recent years at these centers. The high prevalence of MIS failures occurring within 24 months is disturbing and warrants further investigation.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 275 - 275
1 Jul 2011
Burnett RSJ Aggarwal A Givens SA McClure JT Barrack RL
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Purpose: Prophylactic antibiotics are frequently withheld until cultures are obtained in revision TKA. A prospective study was undertaken to determine whether prophylactic pre-operative IV antibiotics would affect the results of cultures obtained intra-operatively.

Method: A consecutive series of 25 TKA’s with a known infecting organism were enrolled over 36 months. Inclusion criteria: clinically infected TKA, a known preoperative infecting organism, and no recent antibiotic therapy. Re-aspiration of the infected TKA was performed following anesthesia and sterile prep. IV antibiotic prophylaxis was then administered and the tourniquet was then inflated. Intra-operative culture swabs and tissue were obtained at arthrotomy. The timing of events was recorded. Pre/post antibiotic culture data were analyzed to determine the effect of IV preoperative prophylactic antibiotics on cultures obtained intra-operatively.

Results: Mean time from end of antibiotic infusion to tourniquet inflation was 15 minutes; to arthrotomy culture was 25 minutes. In all 25 knees the organism(s) cultured at arthrotomy were the same as obtained at pre-operative aspiration. In 24 knees the organism cultured was sensitive to the preoperative prophylactic antibiotics given (Ancef and Vancomycin); one patient grew Candida albicans.

Conclusion: Pre-operative prophylactic antibiotics did not affect the results of intra-operative cultures, and should not be withheld prior to infected TKA surgery when an organism has been identified on aspiration. Based on these results, holding pre-operative antibiotics prior to revision TKA is rarely justified.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 253 - 253
1 Jul 2011
MacDonald SJ Barrack RL Rosenzweig S Guerin JF McCalden RW Bohm E Bourne RB Rorabeck CH
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Purpose: There are two broad-based categories of cementless femoral components performed during total hip arthroplasty: proximally coated versus fully porous coated. While both have enjoyed widespread clinical applications, there remains debate regarding differences in clinical outcome scores, relative incidence of thigh pain and the development of stress shielding. The purpose of this study was to investigate these variables in a multi-center prospective randomized blinded clinical trial.

Method: Between three centers 388 patients were enrolled in this clinical trial. 198 patients received a proximally coated tapered cementless femoral component (Synergy, Smith and Nephew, Memphis) and 190 patients received a fully porous coated cementless femoral component (Prodigy, Depuy, Warsaw). Patients were evaluated pre-operatively, at 3, 6, 12 months and annually thereafter, with multiple validated outcome measures including WOMAC, SF12, HSS, UCLA activity and thigh pain scores. A cohort of 72 patients underwent preoperative and postoperative DEXA scanning.

Results: 367 patients had a minimum of 2 years follow-up (average 6.4 years). There were no differences in age at surgery, BMI, or pre-operative clinical outcome scores (WOMAC, SF12, HSS, UCLA activity, thigh pain) between groups. There were no differences in any post-operative clinical outcome scores at any interval of follow-up. There were no differences in incidence of thigh pain between groups at any time. The only measurable difference between study groups was in bone mineral density evaluation. Bone density change in Gruen zone 7 was 23.7% with the Prodigy stem and 15.3% with the Synergy stem (p=0.011).

Conclusion: Both fully porous coated and proximally porous coated cementless stems performed well, with no clinical differences at a minimum of 2 years follow-up. Only bone mineral density evaluations could detect any differences between these femoral components designs.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_III | Pages 548 - 548
1 Aug 2008
Soler JA Haddad F Barrack RL
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Introduction: Third generation fixation systems allow for the retightening of cables, and are associated with high rates of trochanteric union. This is a prospective study undertaken to evaluate the outcome of the first 40 patients treated with a third generation cable plate and trochanteric hook system.

Methods: 36 patients treated by two revision hip arthroplasty surgeons using a third generation cable plate system were enrolled and followed up. These included 28 females and 12 males with an average age of 64 (range: 48–91). Large hooks were used in 30 with an average of 4.8 cables (range: 4–9). The need to retighten cables intra-operatively was noted. Clinical and radiographic follow-up was undertaken at 2 years.

Results: A third generation fixation system was used for 16 peri-prosthetic fractures, 6 trochanteric non unions, 5 structural femoral allografts, 6 complex revisions and for trochanteric advancement in 3 cases. The first cable tightened was loose by the end of the procedure in the majority of cases and had to be retightened. There were no cases of fretting or cable breakage. Two further trocanteric non unions needed re-fixation and bone grafting in a further procedure

Discussion and Conclusion: Third generation cable system allow for re-tightening, as the cable is not damaged by the crimping mechanism. This facility appears critical as some retightening is invariably required in the process of applying this type of device. There were only 2 re-operations for trochanteric non unions, but the overall outcomes were otherwise excellent, with no fretting or cable breakage. Modern cable systems afford improved, more flexible trochanteric fixation possibilities.