This study used model-based radiostereometric analysis (MBRSA) to compare migration of a recently introduced cementless hip stem to an established hip stem of similar design. Novel design features of the newer hip stem included a greater thickness of hydroxyapatite coating and a blended compaction extraction femoral broach. Fifty-seven patients requiring primary total hip arthroplasty (THA) were enrolled at a single centre. Patients were randomized to receive either an Avenir collarless stem and Trilogy IT cup (ZimmerBiomet) or a Corail collarless stem and Pinnacle cup (DePuy Synthes) via a posterior or lateral approach. Both stems are broach-only femoral bone preparation. RSA beads (Halifax Biomedical) were inserted into the proximal femur during surgery. Patients underwent supine RSA imaging a 6 weeks (baseline), 6, 12, and 24 months following surgery. The primary study outcome was total subsidence of the hip stem from baseline to 24 months as well as progression of subsidence between 12 and 24 months. These values were compared against published migration thresholds for well-performing hip stems (0.5mm). The detection limit, or precision, of MBRSA was calculated based on duplicate examinations taken at baseline. Patient reported outcome measures were collected throughout the study and included the Oxford-12 Hip Score (OHS), EuroQoL EQ-5D-5L, Hip Osteoarthritis Score (HOOS) as well as visual analogue scales (VAS) for thigh pain and satisfaction. Analysis comprised of paired and unpaired t-tests with significance set at p≤0.05. Forty-eight patients (30 males) were included for analysis; 7 patients received a non-study hip stem intra-operatively, 1 patient suffered a traumatic dislocation within three weeks of surgery, and 1 patient died within 12 months post-surgery. RSA data was obtained for 45 patients as three patients did not receive RSA beads intra-operatively. Our patient cohort had a mean age of 65.9 years (±;7.2) at the time of surgery and body mass index of 30.5 kg/m2 (±;5.2). No statistical difference in total stem migration was found between the Avenir and Corail stems at 12 months (p=0.045, 95%CI: −0.046 to 0.088) and 24 months (p=0.936, 95% CI: −0.098 to 0.090). Progression of subsidence from 12-24 months was 0.011mm and 0.034mm for the Avenir and Corail groups which were not statistically different (p=0.163, 95%CI: −0.100 to 0.008) between groups and significantly less than the 0.5mm threshold (pNo statistically significant differences existed between study groups for any pre-operative function scores (p>0.05). All patients showed significant functional improvement from pre- to post-surgery and no outcome measures were different between study groups with exception of EQ-5D-5L health visual analogue scale at 12 months which showed marginally superior (p=0.036) scores in the Avenir group. This study was not powered to detect differences in clinical outcomes. This study has demonstrated no statistical difference in subsidence or patient-reported outcomes between the Corail hip stem and the more recently introduced Avenir hip stem. This result is predictable as both stems are of a triple-tapered design, are coated with hydroxyapatite, and utilize a broach-only bone preparation technique. Both stem designs demonstrate migration below 0.5mm suggesting both are low-risk for aseptic loosening in the long-term.
Proximal junctional kyphosis (PJK) is defined as adjacent segment kyphosis >10° between the upper instrumented vertebrae and the vertebrae 2 levels above following scoliosis surgery. There are few studies investigating the predictors and clinical sequelae involved with this relatively common complication. Our purpose was to determine the radiographic predictors of post-op PJK and to examine the association between PJK and pain/HRQOL following surgery for AIS. The Post-Operative Recovery after Scoliosis Correction: Home Experience (PORSCHE) study was a prospective multicenter cohort of AIS patients undergoing spinal fusion surgery. Pre-op and minimum 2 year f/u scoliosis and sagittal spinopelvic parameters (thoracic kyphosis–TK, lordosis–LL, pelvic tilt-PT, sacral slope-SS, pelvic incidence-PI) were measured and compared to numeric rating scale for pain (NRS) score, SRS-30 HRQOL and to the presence or absence of PJK (proximal junctional angle >100). Continuous and categorical variables were assessed using logistic regression and binomial variables were compared to binomial outcomes using chi-square. 163 (137 females) patients from 8 Canadian centers met inclusion criteria. At final f/u, PJK was present in 27 patients (17%). Pre-op means for PJK vs No PJK: Age 14.1 vs 14.7yr; females 85 vs 86%; scoliosis 57±22 vs 62±15deg; TK 28±18 vs 19±16deg ∗, LL 62±11 vs 60±12deg, PT 8±12 vs 10±10deg, SS 39±8 vs 41±9deg, PI 47±14 vs 52±13deg, SVA −9±30 vs −7±31mm. Final f/u for PJK vs No PJK: Scoliosis 20±11 vs 18±8deg, final TK 26±12 vs 19±10deg∗, LL 60±11 vs 57±12deg, PT 9±12 vs 12±13deg, SS 39±9 vs 41±9deg, PI 48±17 vs 52±14deg, SVA −23±26 vs −9±32mm∗. Significant findings: Pre-op kyphosis >40deg has an odds ratio (OR) of 4.41 (1.50–12.92) for developing PJK∗. The presence of PJK was not associated with any significant differences in NRS or SRS-30. ∗denotes p<0.05. This prospective multicenter cohort of AIS patients demonstrated a 17% risk of developing PJK. Pre-op thoracic kyphosis >40deg was associated with the development of PJK; however, the presence of PJK was not associated with increased pain or decreased HRQOL.
Total hip arthroplasty (THA) is a highly successful procedure achieving excellent clinical outcomes beyond 10 years post-surgery. With exception of periprosthetic infection, dislocation is the most common cause of failure in THA. A novel reverse total hip (RTH) replacement has been developed to address dislocation through reversal of the typical THA articulation in which a femoral cup and acetabular ball interlock at the extremes of motion to enhance mechanical stability in all planes. The purpose of this study was to assess the safety and efficacy of this novel RTH in a series of 22 patients and to monitor implant fixation using radiostereometric analysis (RSA). Twenty two patients with end-stage osteoarthritis of the hip were enrolled between 2017 and 2019 at a single center. All surgeries were performed by a group of four high-volume fellowship-trained arthroplasty surgeons. All patients received at least 1 acetabular cup screw and RSA markers inserted into the acetabulum and proximal femur. Follow-up time points were 6 weeks, 6, 12 and 24 months and included patient reported outcome measures (HOOS, Oxford-12, Harris Hip Score, SF-36 and Satisfaction) as well as RSA assessment.Introduction
Methods
The evolution of operative technology has allowed correction of complex spinal deformities. Neurological deficits following spinal instrumentation is a devastating complication and the risk is especially high in those with complex sagittal and coronal plane deformities. Prior to intraoperative evoked potential monitoring, spinal cord function was tested using the Stagnara Wake up test, typically performed after instrumentation once the desired correction has been achieved. This test is limited as it does not reflect the timeframe in which the problem occurred and it may be dangerous to some patients. Intraoperative neuromonitoring allows timely feedback of the effect of instrumentation and curve correction on the spinal cord. Pedicle screws that are malpositioned can result in poor fixation or neuronal injury. Evoked EMG monitoring can aid in accurate placement. A positive EMG response can alert the surgeon to a potential pedicle breech and allow them to reassess the placement of their hardware intraoperatively. The stimulation threshold is affected by the amount of surrounding bone acting as an insulator to electrical conduction and is variable in different regions of the spine. In the non-deformed, lumbar spine stimulation thresholds have been established. Such guidelines have not been well-developed for the thoracic spine, or for severely scoliotic spines. Thus our primary objective was to compare the stimulation threshold of the apical pedicle on the concave side to the stimulation threshold of the pedicles at the upper and lower instrumented levels. Intraoperative EMG stimulation thresholds were done at 192 apical pedicles on the concave side of the deformity and then compared to those thresholds found at 169 terminal level pedicles. Only pedicles for which a stimulation threshold was found were reported and excluded those where a breech was suspected. The lowest stimulation required for an EMG response was documented to a maximum stimulation of 20 mA. The mean threshold at the apex was 16.62 milliamps (mA) compared to 18.25mA at the terminal levels. This was compared with the t-test and showed a statistically significant difference (p<0.05). In this study we report only the thresholds for the concave side, the pedicle that is most likely to be reduced in size. The threshold for stimulation is reduced compared to those seen at the highest and lowest instrumented level. Most of the apexes are located in the mid-thoracic spine with the highest instrumented levels being in the high thoracic spine and the lowest levels being in the lumbar spine. This study provides preliminary evidence that the apical, concave pedicle has a lower threshold than the end pedicles and one cannot rely on established thresholds from different areas of the spine. The surgeon should be cognisant of these differences when instrumenting at the apical level. Ongoing work is examining the convex apex threshold as well as the relationship between the effect of age and a diagnosis other than adolescent idiopathic scoliosis.
The purpose of this study was to compare the clinical outcomes and complications following bilateral simultaneous total knee arthroplasty in high body mass index (BMI) patients(>30kg/m2) to those of patients with a BMI<30 kg/m2. Using data from an academic arthroplasty database and review of clinic charts we obtained health related quality of life (SF-12), and disease specific functional outcome scores (WOMAC or Oxford Knee Score). We also assessed length of hospital stay, ASA grade and transfusion requirements. Sixty six patients had a BMI<30 and 151 patients had a BMI>30.Introduction
Materials and Methods
The efficiency of brace treatment for adolescent idiopathic scoliosis is correlated to how the brace has been worn. A smart orthosis was developed to maintain the interface pressure between the brace and the body within the prescribed range during daily activity. Six patients with scoliosis, with Cobb angles of 31 +/− 5 degrees, who were new brace candidates were recruited. They used the system for four weeks: two weeks with monitoring only and two weeks with an automatic feedback activated. The time that the pressure level was in target level range during the study period was increased from 53 +/− 9% to 68 +/− 14% with the feedback activated. This work helps brace candidates wear their braces more effectively and receive the most benefit from the brace treatment. As a result, all subjects who participated in the study maintained their Cobb angles within + two degrees during the study period. Brace correction based upon mechanical action requires appropriate interface pressure between the body and the brace. A smart orthosis was developed to record how much time (quantity) a brace was worn, how well (quality) it was used and how well the interface pressure was maintained to the prescribed level. Six subjects were recruited and they all were fitted with Boston style braces. Each subject wore the brace for 2 weeks without the force maintenance system activated to serve as the control period, and the remaining 2 weeks with the force maintenance system activated. During the automatic feedback mode, the pressure maintenance system was activated only during the daytime hours (8:00–22:00hrs) to avoid disturbing the patients during sleep. The subject could either return the system to us after 1 month or continue to use the system until the next clinic. The time that the pressure level was in the target level range during the study period was increased from 53 +/− 9% to 68 +/− 14% with the feedback activated. The average brace wear time for the study period was 72 +/− 15% (12.6hr/day) of the prescribed time (17.5 +/− 3.8 hours). The curve severity of all subjects on the following clinical visit was the same (within measurement error) as the first visit (32 +/− 5 vs 31 +/− 5 degrees). Compliance was not affected when wearing the monitor. The smart orthosis was able to improve the efficiency of a conventional brace by maintaining the prescribed interface pressure automatically. This project helps brace candidates wear their braces more effectively and gets the most benefit from the brace treatment. As a result, all participating subjects maintained their Cobb angle within +/− 2 degrees during the study period.
To determine the pattern of brace wear compliance over time in both day and night time wear by using objective force measurements within the brace. Twenty subjects who were diagnosed of AIS, age between nine and fifteen years, and new to brace treatment were recruited in this study. To use the data for analysis, only subjects who used the brace for five hours continuously either in daytime or nighttime were considered. For daytime wear, the selected five hour intervals had to begin with an initial spike in force after a period of non-activity as recorded by the transducer, which would indicate that they had just put on the brace. At night, the measurements began at one am and ended at six am. Among the twenty subjects, only nine subjects’ data were used for daytime and eleven subjects’ data were used in nighttime. The average wear period was 11.4 ± 4.3 days for the day group, 11.6 ± 3.9 days for the night group. There was a statistically significant decrease in force within the first five hours of consecutive brace wear during daytime hours. The decrease was from 1.4 ± 0.6 (140% of prescribed force) in the first hour to 1.0 ± 0.6 in the fifth hour, a difference of 0.4, which is a 29% drop from the initial force. Most of the drop in force happened between hour one and hour two, as the difference in those two hours is 0.2 ± 0.1 (p = 0.001); between hours two and five the difference did not reach statistical significance. The observed difference between hours one and five for the night group was 0.2 ± 0.2, p = 0.06, which did not reach significance as well. Daytime forces in a Boston Brace tend to decrease over a period of time, but the nighttime forces seem to be maintained at the same level. These results show that daily adjustment of the brace tightness may be required to maintain the tightness level and the efficiency of brace treatment.
Image guided navigation systems for total knee replacement surgery (TKR) are gaining popularity in an effort to improve both alignment and functional outcome. This trial was undertaken to compare one year functional outcome and radiological alignment of TKRs inserted with and without an image guided navigation system. Patients were randomised to undergo surgery using either an image guided navigation system or traditional instrumentation. Pre and post-operative Knee Society (KSS), WOMAC and SF-36 scores were collected. Postoperatively, limb and implant alignment &
rotation were assessed using both full-length films and CT scans. One hundred and twenty-three patients (one hundred and forty-five knees) were enrolled: eighty-one females, forty-two males, mean age sixty-seven years. Age, gender and pre-operative range of motion, KSS WOMAC and SF-36 scores did not differ between the groups. While there was no statistically significant difference in postoperative KSS, WOMAC and seven of eight SF-36 subscales, the navigated group demonstrated better post-operative SF-36 General Health Scores. Mean postoperative flexion in all patients was 115°, and did not differ between groups. Mean post-operative leg alignment demonstrated more varus in the navigated group (2.1°) versus the non-navigated group (0.9°, p=0.02), however there was a trend towards a smaller standard deviation in the navigated group. Rotational alignment of the femoral component relative to the femur, tibial component relative to the tibia, and tibial component relative to the femoral component were not statistically different between groups; however, there were larger standard deviations of these measures in the non-navigated group. Pre-operative alignment appeared to affect tibial component placement; varus knees had a mean of 3° of tibial component internal rotation while valgus knees had a mean of 12° external rotation. Imaged guided navigation systems appear to reduce the variability in TKR component placement and limb alignment. However, this may not necessarily translate into better mean limb alignment or early functional outcome.
A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection. Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken. Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system. Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0–5.0), respiratory 2.3 (0.8–6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7–4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00. Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.
A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection. Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken. Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system. Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0 – 5.0), respiratory 2.3 (0.8 – 6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7 – 4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00. Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.
Little is known about the priorities of patients undergoing surgery for idiopathic scoliosis. This study explores the priorities of adolescents and contrasts them from their parents and their surgeons. Fifty-five pairs of children and parents underwent structured interviews separately, to explore their concerns, desires and expectations both about scoliosis and surgery. Surgeons of these patients and from across Canada completed a similar questionnaire. We found a significant mismatch between child, parent and surgeon priorities. This mismatch has implications on matters relating to decision making, informed consent, understanding of patient satisfaction, and measuring outcomes that are meaningful to patients. To define the concerns, desires (goals) and expectations of adolescents undergoing surgery for idiopathic scoliosis and to contrast them from their parents and surgeons. We conducted structured interviews of fifty-five pairs of adolescents and parents separately. The questionnaire had sections on concerns, desires and expectations regarding both scoliosis and surgery, with items pertaining to present and future effects on appearance, pain, physical and psychosocial function and health. Parents also reported what their child’s responses might be. Their surgeons (four) and paediatric spine surgeons (twenty-four) across Canada completed the same questionnaire. Analysis involved repeated measures ANOVA, intra-class correlation coefficients and kappa statistics. Parents were more concerned than their children about present and future consequences of scoliosis. Surgeons were least concerned. Children, parents and surgeons agreed that improving physical appearance was the primary goal of surgery. Surgeons agreed very little about the natural history of scoliosis, other goals of surgery and the likelihood of specific outcomes. Parents wanted more from surgery than their children. Parents and patients had greater expectations of surgery than surgeons. Adolescents had different priorities from their parents, but parents were aware of this difference and knew what their child’s priorities were. Adolescents with idiopathic scoliosis, their parents and surgeons have different priorities. This mismatch might stem from uncertainty about the natural history of idiopathic scoliosis for Knowledge of patient priorities is vital for shared decision making, informed consent, understanding patient satisfaction, and for measuring outcomes that matter most to patients.
Orthopaedic Research &
Education Foundation: (Unni. G. Narayanan: AAOS/OREF Health Services research Fellowship award) Canadian Institutes of Health Research: (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson) DePuyAcroMed-Johnson &
Johnson Medical Products (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson) Synthes, Canada (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson)
Revision of massive femoral defects in revision hip arthroplasty is extremely difficult. This study assesses defects where bone loss extends to the isthmus of the femur. By using a medial allogeneic femoral graft in a wedge fashion, rotational and axial stability of the femoral implant is augmented, allowing bone ingrowth to occur. The technique is described which is simple, inexpensive and readily available in most institutions. A medial allogeneic femoral strut graft is assessed in hip arthroplasty revision to improve implant stability and thereby promote bony ingrowth into the implant. Thirty-three revision arthroplasties were preformed in twenty-nine patients (avg. age 63.7 yrs) using a fully-porous coated implant of eight or ten inch length. All patients had a Paprosky Type III or IV femoral defect. The implants, by definition were press-fit at or past the isthmus. To aid ingrowth and to decrease axial and rotational stresses, a medial femoral strut graft was wedged into the remaining medial host bone and under the collar of the implant. Cabling was utilized to prevent dislodgement of the graft from the implant and host. A radiographic and clinical comparison to a series of similar defects without grafting was performed for a minimum of thirty-five month follow-up. Twenty-eight of the thirty-three implants had radiographic evidence of ingrowth with migration of only two millimeters (average). Medial femoral strut grafting displayed much better potential for ingrowth and decreased potential for migration. Harris hip scores averaged eighty-one from a preoperative score of thirty-two. Cost of the grafts averaged $2100 cheaper compared to a bulk structural graft which would otherwise have been used in this situation. Medial femoral strut grafts augment initial implant stability to allow for implant in- growth. The advantages of the medial strut grafts are decreased cost, improved stability, and improved implant in- growth potential.
Five surgeons independently rated clinical photographs of forty patients with AIS. Ratings of shoulder blades, shoulder symmetry, and waist symmetry were related to “overall appearance”, and were also correlated with rib prominence and Cobb angle. Because the components of surgeons’ ratings of appearance differed, this may lead to inconsistent recommendations regarding surgery. To identify patient characteristics associated with surgeons’ ratings of patient physical deformity in Adolescent Idiopathic Scoliosis (AIS). Five surgeons independently rated clinical photographs of forty patients with AIS. Surgeons separately rated the appearance of patients’ shoulder blades, shoulder symmetry, waist symmetry and also rated their “overall appearance Surgeons’ mean rating for “overall appearance” was moderately correlated with rib prominence (r = 0.48), vertebral rotation (r = 0.44) and Cobb angle (r = 0.53). Surgeons’ rating of patients’ “overall appearance” was affected by each of: shoulder blades (p = 0.001), shoulder symmetry (p = 0.01) and waist symmetry (p = 0.001). However, each surgeon weighted components of patients’ appearance differently to arrive at their overall rating of appearance (p<
0.006). Because patients’ physical appearance is an important element of surgical decision making, differences among surgeons could be contributing to inconsistent recommendations. Surgeons’ ratings of physical appearance are based on surgeons’ ratings of patients’ shoulder blades, waist symmetry and shoulder symmetry but surgeons weight those elements differently. Surgeon decision making is complicated. It is based on radiographs and subjective assessment. Patients’ appearance undoubtedly influences surgeon recommendation for surgery. We need to clarify surgeons’ ratings and improve the criteria for surgeon decision making.