Accuracy of cup placement and pelvic motion in total hip arthroplasty in the lateral decubitus position using a new computed tomography-based navigation system with augmented reality technology

INTRODUCTION

This study aimed to investigate the accuracy of cup position and assess the changes in pelvic tilt during primary total hip arthroplasty (THA) in the lateral decubitus position using a new computed tomography (CT)-based navigation system with augmented reality (AR) technology.

MATERIALS AND METHODS

There were 37 cementless THAs performed using a CT-based navigation system with AR technology in the lateral decubitus position and 63 cementless THAs performed using manual implant techniques in the lateral decubitus position in this retrospective study. Postoperative cup radiographic inclination and anteversion were measured using postoperative CT, and the proportion of hips within Lewinnek's safe zone was analyzed and compared between the two groups. The mean absolute values of navigation error were assessed. Intraoperative pelvic tilt angles were also recorded using navigation system.

RESULTS

The percentage of cups inside Lewinnek's safe zone was 100% in the navigation group and 35% in the control group (p < 0.001). The mean absolute values of navigation error in inclination and anteversion were 2.9° ± 2.1° and 3.3° ± 2.4°, respectively. The mean abduction angle of the pelvis was 5.1° ± 4.8° after placing the patients in the lateral decubitus position and 4.1° ± 6.0° after cup placement. The mean posterior tilt angle was 6.8° ± 5.1° after placing the patients in the lateral decubitus position and 9.3° ± 5.9° after cup placement. The mean internal rotation angle was 14.8° ± 7.4° after cup placement. There were no correlations between the navigation error in inclination or anteversion and the absolute values of changes of the pelvic tilt angle at any phase.

CONCLUSIONS

Although progressive pelvic motion occurred in THA in the lateral decubitus position, especially during cup placement, the CT-based navigation system with AR technology improved cup placement accuracy.

Neuropathic pain in patients with osteoarthritis of the hip before and after total hip arthroplasty

OBJECTIVES

The pain associated with osteoarthritis (OA) was thought to be nociceptive; however, neuropathic pain is also observed. We investigated the relationship between hip OA and neuropathic pain using the PainDETECT questionnaire (PDQ).

METHODS

A total of 159 hips of 146 consecutive patients who underwent total hip arthroplasty (THA) with a diagnosis of OA were enrolled in this study. The prevalence of each pain phenotype was evaluated preoperatively and at 6 months postoperatively using the PDQ. Patient characteristics and numerical rating scale (NRS) scores were compared between a group with possible neuropathic pain (NP group) and a group with nociceptive pain (non-NP group).

RESULTS

Before THA, neuropathic, unclear, and nociceptive pain was observed in 18, 36, and 105 hips, respectively. The prevalence in the NP group was 54 hips, accounting for approximately one-third of all hips, which decreased significantly to seven hips after THA. A significantly higher NRS score was observed in the NP group, both before and after THA.

CONCLUSION

Approximately one-third of the patients with hip OA had neuropathic pain. Therefore, neuropathic pain should be considered when treating patients with hip OA.

Comparison between accuracy of augmented reality computed tomography-based and portable augmented reality-based navigation systems for cup insertion in total hip arthroplasty

Augmented reality (AR) has been used for navigation during total hip arthroplasty (THA). AR computed tomography (CT)-based navigation systems and AR-based portable navigation systems that use smartphones can also be used. This study compared the accuracy of cup insertion during THA using AR-CT-based and portable AR-based navigation systems. Patients with symptomatic hip disease who underwent primary THA in the supine position using both AR CT-based and portable AR-based navigation systems simultaneously between October 2021 and July 2023 were included. The primary outcome of this study was the absolute difference between cup angles in the intraoperative navigation record and those measured on postoperative CT. The secondary outcome was to determine the factors affecting the absolute value of the navigation error in radiographic inclination (RI) and radiographic anteversion (RA) of the cup, including sex, age, body mass index, left or right side, approach, and preoperative pelvic tilt. This study included 94 consecutive patients. There were 11 men and 83 women, with a mean age of 68 years. The mean absolute errors of RI were 2.7° ± 2.0° in the AR CT-based and 3.3° ± 2.4° in the portable AR-based navigation system. The mean absolute errors of RA were 2.5° ± 2.1° in the AR CT-based navigation system and 2.3° ± 2.2° in the portable AR-based navigation system. No significant differences were observed in RI or RA of the cup between the two navigation systems (RI: p = 0.706; RA: p = 0.329). No significant factors affected the absolute value of the navigation errors in RI and RA. In conclusion, there were no differences in the accuracy of cup insertion between the AR CT-based and portable AR-based navigation systems.

Two- and three-dimensional evaluations following handheld robot-assisted total knee arthroplasty

Robot-assisted total knee arthroplasty (TKA) has proven to be successful in improving the accuracy of component positioning and reducing radiographic outliers. This study aimed to evaluate and compare the alignment of the components using two- and three-dimensional (2D and 3D) measurements following handheld imageless robot-assisted TKA. Seventy consecutive patients underwent primary TKA at our institution using a handheld robot-assisted system. Full-length standing anteroposterior and lateral radiographs were obtained 2 weeks after surgery for assessment of 2D component alignments. Pre- and postoperative computed tomography (CT) images were obtained to assess 3D component alignment. The reference points defined on preoperative CT images were transferred to the postoperative CT images. The absolute errors in the 2D and 3D component alignments from the planned, validated cutting, and validated implantation angles were calculated. Outliers of >  ± 3° of femoral and tibial component alignments in the coronal and sagittal planes were also investigated. All absolute errors in the 2D and 3D component alignments were < 1°, except for the planned and validated cutting angles of the femoral sagittal alignment. No outliers were observed in the femoral or tibial component in the coronal plane. Significant differences between the 2D and 3D measurements were observed for the mean absolute value from the planned and validated cutting angles in the femoral sagittal plane and from the validated implantation angle in the tibial coronal plane. The handheld robot-assisted system demonstrated a high accuracy for component alignment using 2D and 3D evaluations.

Comparison of accuracy and early outcomes in robotic total knee arthroplasty using NAVIO and ROSA

This study aimed to compare the cutting and component placement accuracies and early outcomes after total knee arthroplasty (TKA) between an image-free handheld robotic system (NAVIO) and a radiography-based robotic system (ROSA). This retrospective study included 88 patients (88 knees) who underwent TKA using the NAVIO (40 patients) or ROSA (48 patients) robotic systems. The accuracies of the robotic systems were compared. Clinical scores were evaluated using the Knee Society Score 2011 (KSS 2011) and the forgotten joint score (FJS)-12 at 1 year postoperatively. The femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group. The other cutting errors were not statistically different in both groups. Implantation errors did not differ between the groups. Regarding the clinical outcomes of the KSS 2011 subscales, the symptoms score was higher in knees operated using ROSA than in those using NAVIO. The other KSS 2011 subscales and the FJS-12 showed no differences between the two groups. In conclusion, the femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group, and the KSS 2011 symptom score subsection at one year was higher in the knees operated using ROSA than in those using NAVIO.

Minimum 7-year results of cementless total hip arthroplasty with vitamin E-diffused and 2-methacryloyloxyethyl phosphorylcholine-grafted highly cross-linked polyethylene

The purpose of this study was to evaluate the mid-term clinical results and polyethylene wear of vitamin E-diffused highly cross-linked polyethylene (HXLPE) and 2-methacryloyloxyethyl phosphorylcholine (MPC)-grafted HXLPE in cementless total hip arthroplasty (THA). Thirty-four THAs with vitamin E-diffused HXLPE (VEPE) and 32-mm cobalt-chromium head, and 116 THAs with MPC-grafted HXLPE and 32-mm alumina head were evaluated. The Merle d'Aubigné and Postel scores were administered. Kaplan-Meier survivorship was analyzed. Annual radiographs were analyzed using computerized method and linear steady-state wear rate was measured. The mean duration of follow-up was 9 years (range, 7-11 years) in VEPE group and 8 years (range, 7-10 years) in MPC group. The mean Merle d'Aubigné and Postel scores improved postoperatively in both groups. Kaplan-Meier survivorship with endpoint of revision was 100% (95% confidence interval, 100%-100%) in VEPE group and 98.3% (95% confidence interval, 93.4%-99.6%) in MPC group at 10 years (P = .44). The mean steady-state wear rate was 0.007 mm/year in VEPE group and 0.006 mm/year in MPC group (P = .60). The clinical results of both groups were good and wear rates of both liners were very low.

Registration in the supine position improve the accuracy of cup placement in total hip arthroplasty using a portable navigation system

Portable navigation systems have been developed for use in total hip arthroplasty (THA) in recent years. Although intraoperative registration in the lateral decubitus position or the supine position is need to create the three-dimensional coordinate system, it is not clear which position is appropriate. The purpose of this study was to assess the accuracy of cup placement in primary THA in the lateral decubitus position using an image-free handheld navigation device with registration in the lateral decubitus or the supine position, and clarify which position is appropriate. This retrospective study included 129 consecutive cementless THAs performed using an image-free handheld navigation device in the lateral decubitus position. Registration in the first 68 hips was performed in the lateral decubitus position and the last 61 hips was performed in the supine position. Postoperative cup radiographic inclination and radiographic anteversion were assessed, and the accuracy was compared between the two groups. The mean absolute errors of the postoperative measured inclination and anteversion from the target angles were 3.9° ± 2.2° and 4.8° ± 3.5° in the lateral group and 2.9° ± 2.7° and 3.2° ± 2.7° in the supine group (p < 0.05). The percentage of cups inside Lewinnek's safe zone was 94% in the lateral group and 95% in the supine group (ns). The mean absolute values of navigation error in inclination and anteversion were 3.1° ± 2.1° and 4.2° ± 2.8° in the lateral group and 2.3° ± 2.0° and 3.1° ± 2.4° in the supine group (p < 0.05 and p < 0.05). Registration in the supine position improved the accuracy of cup insertion compared with the lateral decubitus position in THA using an image-free handheld navigation device in the lateral decubitus position.

Two- and three-dimensional measurements of leg length change using an accelerometer-based portable navigation system in total hip arthroplasty

BACKGROUND

The aim of this study was examining the accuracy of accelerometer-based portable navigation systems (HipAlign) when measuring leg length changes using two-dimensional (2D) and three-dimensional (3D) methods.

METHODS

Inclusion criteria were patients ≥ 20 years old with symptomatic hip disease who underwent primary total hip arthroplasty (THA) in the supine position using HipAlign between June 2019 and April 2020. The exclusion criteria were patients who underwent THA via a posterior approach. We examined correlations between the leg length change measurement with HipAlign and either 2D or 3D measurement. We performed a multivariate analysis to determine which factors may have influenced the absolute error results.

RESULTS

This study included 34 patients. The absolute error in leg length change between the HipAlign and 3D measurement (4.0 mm) was greater than the HipAlign and 2D measurement (1.7 mm). There were positive correlations between leg length change with HipAlign and 2D and 3D measurements. Male patients had larger errors with 2D measurement. No significant factors were identified for 3D measurement.

CONCLUSION

HipAlign provided acceptable measurement accuracy for leg length changes.

Predicting outcomes after total knee arthroplasty using intraoperative knee kinematics measured by navigation

OBJECTIVES

The objective of the study is to evaluate the relationship between clinical results following posterior-stabilized total knee arthroplasty (TKA) and intraoperative kinematic pattern determined from navigation.

METHODS

Participants were patients with knee osteoarthritis and varus deformity who underwent primary posterior-stabilized TKA. Preoperative and post-implantation kinematic data were recorded, and all kinematic patterns were divided into two types: medial pivot (MP) or non-MP. Knees with MP and non-MP patterns after implantation were compared in terms of postoperative flexion angle, pain, patient satisfaction, expectations, and activity using the new Knee Society Score 2011 at 1 year postoperatively.

RESULTS

This study involved 55 patients (12 men, 43 women) with a mean age of 73.1 years and mean body mass index of 26.5 kg/m2. Preoperative kinematic measurements showed MP in 23 knees and non-MP in 32 knees. After implantation, navigation showed MP in 25 knees and non-MP in 30 knees. No significant differences were found between kinematic patterns preoperatively and after implantation. Postoperative flexion angle, pain, patient satisfaction, expectations, and activity using Knee Society Score 2011 showed no differences between MP and non-MP knees.

CONCLUSION

Intraoperative knee kinematics as measured by navigation could not predict postoperative outcomes of TKA.

Long-term results of hemi-resurfacing and metal-on-metal hip resurfacing for osteonecrosis of the femoral head

PURPOSE

Hemi-resurfacing arthroplasty (Hemi) and metal-on-metal hip resurfacing arthroplasty (HR) were proposed as alternatives to conventional total hip arthroplasty (THA) for patients with osteonecrosis of the femoral head (ONFH). Long-term results were evaluated.

METHODS

Twenty-three hips with ONFH were treated, using Hemi in 12 and HR in 11. Mean follow-up was 15 years in the Hemi group and 10 years in the HR group. Long-term outcomes were reviewed retrospectively.

RESULTS

In the Hemi group, 8 hips showed acetabular protrusion and were revised to THA. One of the 8 hips showed femoral loosening. In the HR group, pseudotumor was detected in 4 hips (36%), and 1 hip was revised due to symptomatic pseudotumor. No evidence of any femoral or acetabular loosening was seen in the HR group. Ten-year survival rates were 64.2% and 90.9% in the Hemi and HR groups, respectively. Survival rate in the Hemi group dropped to 22.9% at 15 years.

CONCLUSIONS

Long-term results of Hemi for patients with ONFH were very poor, and Hemi should not continue to be used. Although HR had a concern of pseudotumor, it could offer attractive indications for 10 years.

Association between pre- and postoperative rotational mismatches of the femorotibial components and bones in bi-cruciate retaining and posterior stabilized total knee arthroplasty

To clarify the association between pre- and postoperative rotational mismatches of the femorotibial components and bones for total knee arthroplasty (TKA) with bi-cruciate retaining (BCR) design and with fixed bearing posterior stabilized (PS) design. This retrospective cohort study included 40 BCR TKAs and 50 PS TKAs. Pre- and postoperative rotational mismatches of the femorotibial components and bones were measured by three-dimensional assessment based on computed tomography imaging. The mean value and percentage within ± 5° of pre- and postoperative rotational mismatches were compared between BCR TKA and PS TKA. Correlations between pre- and postoperative rotational mismatches of the femorotibial components and bones were investigated in BCR TKA and PS TKA. There was no significant difference in mean preoperative rotational mismatch of femorotibial components and bones between BCR TKA and PS TKA. Mean postoperative rotational mismatch of femorotibial components and bones was significantly greater in BCR TKA than in PS TKA. Postoperative rotational mismatch of the femorotibial components was within ± 5° in 21 knees (52.5%) for BCR TKA and in 43 knees (86.0%) for PS TKA. The rate of postoperative rotational mismatch of the femorotibial components and bones within ± 5° was significantly lower for BCR TKA than for PS TKA. In BCR TKA, there was a positive correlation between pre- and postoperative rotational mismatches of the femorotibial components and of bones. We consider these results can be attributed to the retention of both cruciate ligaments, which may affect the reduction of rotational permittance of the components and bones.

Accuracy of augmented reality with computed tomography-based navigation in total hip arthroplasty

BACKGROUND

Augmented reality (AR) provides the surgeon with direct visualization of radiological images by overlaying them on the patient. This study aimed to evaluate the accuracy of cup placement using a computed tomography (CT)-based AR navigation system.

METHODS

Sixty-five prospectively enrolled patients underwent primary cementless total hip arthroplasty (THA) in a supine position using this novel AR navigation system, and changes in pelvic flexion angle (PFA) were evaluated. Absolute navigation errors were defined as the absolute differences between angles in the intraoperative navigation record and those measured on postoperative CT. Factors affecting the absolute navigation error in cup alignment were determined.

RESULTS

Mean absolute change in PFA between preoperative CT and reduction was 2.1° ± 1.6°. Mean absolute navigation errors were 2.5° ± 1.7° in radiographic inclination (RI) and 2.5° ± 2.2° in radiographic anteversion (RA). While no factors significantly affecting absolute navigation error were found for RI, absolute change in PFA between preoperative CT and reduction correlated significantly with the absolute navigation error for RA.

CONCLUSION

This CT-based navigation system with AR enabled surgeons to place the cup more accurately than was possible by freehand placement during THA in a supine position.

Comparing an imageless hand-held robotic-assisted system versus conventional technique for component positioning and early clinical outcomes in total knee arthroplasty

BACKGROUND

This study aimed to examine the component positioning and early clinical outcomes in total knee arthroplasty (TKA) using an imageless hand-held robotic-assisted system compared with those without robotics.

METHODS

Component positioning, hip-knee-ankle angle (HKA), and clinical outcome 1-year postoperatively were compared between 40 patients who underwent TKA with Navio (robot group) and 40 control patients who underwent TKA with a jig-based technique (manual group). The clinical outcomes evaluated were range of motion and the 2011 Knee Society Score.

RESULTS

Implantation errors in the coronal and sagittal alignments were significantly fewer in the robotic group than in the manual group. All knees in the robotic group achieved component positions within 3°. However, the HKA and clinical outcomes did not differ between the groups.

CONCLUSION

Although the accuracy of implantation in the robotic group was superior to that in the manual group, the clinical outcomes were similar.

Outcome of Irrigation and Debridement with Topical Antibiotic Delivery Using Antibiotic-Impregnated Calcium Hydroxyapatite for the Management of Periprosthetic Hip Joint Infection

We assessed the clinical results of irrigation and debridement (I&D) with antibiotic-impregnated calcium hydroxyapatite (CHA) as a novel antibiotic delivery system for the treatment of prosthetic-joint-associated infection (PJI) after total hip arthroplasty (THA). Thirteen patients (14 hips) treated with I&D for PJI after THA at our institution between 1997 and 2017 were retrospectively evaluated. The study group included four men (five hips) and nine women, with an average age of 66.3 years. Four patients (five hips) had symptoms of infection within less than 3 weeks; however, nine patients had symptoms of infection over 3 weeks. All patients received I&D with antibiotic-impregnated CHA in the surrounding bone. In two hips (two cups and one stem), cup and/or stem revision were performed with re-implantation because of implant loosening. In ten patients (11 hips), vancomycin hydrochloride was impregnated in the CHA. The average duration of follow-up was 8.1 years. Four patients included in this study died of other causes, with an average follow-up of 6.7 years. Eleven of thirteen patients (12 of 14 hips) were successfully treated, and no signs of infection were observed at the latest follow-up. In two patients (two hips) for whom treatment failed, infection was successfully treated with two-stage re-implantation. Both patients had diabetes mellitus and symptoms of infection over 3 weeks. Eighty-six percent of patients were successfully treated. No complications were observed with this antibiotic-impregnated CHA. I&D treatment with antibiotic-impregnated CHA produced a higher rate of success in patients with PJI after THA.

Ultra-High-Molecular-Weight Polyethylene in Hip and Knee Arthroplasties

Ultra-high-molecular-weight polyethylene (UHMWPE) wear and particle-induced osteolysis contribute to the failure of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Highly crosslinked polyethylene (HXLPE) was developed in the late 1990s to reduce wear and has shown lower wear rates and loosening than conventional UHMWPE in THA. The irradiation dose for crosslinking is up to 100 kGy. However, during crosslinking, free radical formation induces oxidation. Using HXLPE in THA, the cumulative revision rate was determined to be significantly lower (6.2%) than that with conventional UHMWPE (11.7%) at a mean follow-up of 16 years, according to the Australian Orthopaedic Association National Joint Replacement Registry. However, HXLPE does not confer to TKA the same advantages it confers to THA. Several alternatives have been developed to prevent the release of free radicals and improve polymer mechanical properties, such as thermal treatment, phospholipid polymer 2-methacryloyloxyethyl phosphorylcholine grafting, remelting, and vitamin E addition. Among these options, vitamin E addition has reported good clinical results and wear resistance similar to that of HXLPE without vitamin E, as shown by short-term clinical studies of THA and TKA. This review aims to provide a comprehensive overview of the development and performance of UHMWPE in THA and TKA.

High rates of outliers in computer-assisted high tibial osteotomy with excellent mid-term outcomes

PURPOSE

The primary aim was to evaluate the accuracy of navigation in opening wedge high tibial osteotomy (HTO). The secondary aim was to examine mid-term outcomes after HTO.

METHODS

Inclusion criteria were patients with medial compartment knee osteoarthritis who underwent computer-assisted HTOs. Mechanical axis (MA), percentage MA (%MA), and change in posterior tibial slope (ΔPTS) were displayed on the navigation screen. Radiographic examinations included hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), and PTS. Preoperative and 5 weeks postoperative standing radiographs of the whole lower extremity and knee were used. Clinical evaluations were performed using American Knee Society knee score and function score both preoperatively and at last follow-up. Radiographic evaluations were performed by orthopedic surgeons. Intraoperative navigation after osteotomy and postoperative standing radiograph were compared. MA (HKA), %MA, and ΔPTS were compared. Outliers were defined as > 3° in MA, > 10% in %MA, and > 10° in ΔPTS. Outlier and non-outlier groups were compared. The rate of conversion to arthroplasty was examined.

RESULTS

This study involved 38 patients (44 knees) and last follow-up was at a mean of 5 years (range, 1-9 years). Mean American Knee Society knee score and function score improved significantly from 59 to 69 preoperatively to 95 and 85 at last follow-up, respectively. Absolute values of mean errors for MA, %MA, and ΔPTS were 2.1°, 9.3%, 1.2°, respectively. Outlier rates were 18% in MA, 39% in %MA, and 5% in ΔPTS. No significant factors were found in MA and ΔPTS. In %MA, preoperative JLCA was significantly higher in the outlier group compared to the non-outlier group. No knees underwent conversion to total knee arthroplasty. No differences in outcomes were found between outlier and non-outlier groups.

CONCLUSION

Although rates of outlier values in computer-assisted opening wedge HTO were high, mid-term outcomes were excellent.

LEVEL OF EVIDENCE

IV.

Minimum 10-Year Results of Modular Metal-On-Metal Total Hip Arthroplasty

Background: this study aimed to assess the long-term outcomes of (a minimum of 10-years) total hip arthroplasty with a metal-on-metal acetabular prosthesis. Methods: Eighty-nine primary total hip arthroplasties (82 patients) were performed using a Pinnacle modular metal-on-metal acetabular prosthesis. Clinical hip function outcomes were evaluated using the Japanese Orthopaedic Association hip score preoperatively and at the final follow-up. Radiological analysis was performed at the final follow-up and magnetic resonance imaging in all hips postoperatively. Results: Out of 82 patients, 17 were excluded who were followed up for <10 years. Of the remaining 65 patients (70 hips), 19 (20 hips) developed pseudotumors during 2−10 years postoperatively. After 10 and 13 years, the survival rates of revision endpoint were 93.6% and 90.4%, respectively. Clinical hip function outcomes had improved significantly at the final follow-up. In the radiological analysis, the mean cup angle of inclination and mean ratio of femoral offset on the operated hip to the contralateral hip was highest in patients with revision surgery for adverse reactions to metal debris. Conclusions: This study showed a 29.0% prevalence of pseudotumors. Some cases required revisions even after 10 years following surgery. Regular clinical surveillance is recommended for the early detection of adverse reactions to metal debris.

Intraoperative midflexion medial laxity using navigation affects patient expectations following posterior stabilized total knee arthroplasty

BACKGROUND

Patient satisfaction and expectations are now recognized as an outcome measure for successful total knee arthroplasty (TKA). The purpose of this study was to determine which factors including soft tissue balance during surgery affect patient satisfaction and expectations after TKA.

METHODS

A total of 135 patients (157 knees) with knee osteoarthritis who underwent primary TKA with a posterior stabilized design were studied. After implantation of all components, varus/valgus laxity of the knee was measured intraoperatively with the knee at 0°, 30°, 60°, 90°, and 120° guided by an image-free navigation system. Factors that affected patient satisfaction and expectations, including lateral and medial laxities, were evaluated using the 2011 Knee Society score.

RESULTS

The mean intraoperative lateral laxity was 1.1°, 1.6°, 0.9°, 1.3°, and 1.7° with the knee at 0°, 30°, 60°, 90°, and 120°, respectively. The mean intraoperative medial laxity was 1.1°, 1.4°, 1.1°, 1.1°, and 1.7° with the knee at 0°, 30°, 60°, 90°, and 120°, respectively. Patient satisfaction after TKA correlated positively with symptom (R = 0.61, p < 0.01) and functional activity (R = 0.47, p < 0.01) scores. Patient expectations after TKA weakly positively correlated with symptom (R = 0.29, p < 0.01) and functional activity (R = 0.20, p = 0.01) scores, and weakly negatively with medial laxity at 30° (R = -0.21, p < 0.01).

CONCLUSION

Midflexion medial laxity was associated with worse patient expectations after TKA. Avoiding medial laxity could be one of the important techniques during TKA.

Comparison of the accuracies of computed tomography-based navigation and image-free navigation for acetabular cup insertion in total hip arthroplasty in the lateral decubitus position

Image-free navigation has been proven as reliable as that using computed tomography (CT) in positioning the acetabular cup in total hip arthroplasty (THA), but previous studies rarely included hip dysplasia cases. The purpose of the present study was to determine the accuracies of CT-based navigation and image-free navigation for acetabular cup insertion, including hip dysplasia cases. Sixty-three hips were studied, including 57 with hip dysplasia. The hips were divided into two groups based on the registration point of image-free navigation. In Group I, the ipsilateral anterior superior iliac spine (ASIS) and the L5 spinous process were registered in 31 hips. In Group II, bilateral ASIS points were registered in 32 hips. Final component orientation was measured from postoperative CT scans. The accuracy of cup orientation was compared between CT-based and image-free navigation. In Group I, the cup inclination was more accurate with CT-based navigation (1.9°) than with image-free navigation (4.4°, p=.009). Cup anteversion was also more accurate with CT-based navigation (2.9°) than with image-free navigation (7.1°, p<.001). In Group II, the accuracies of cup inclination and anteversion showed no differences between CT-based and image-free navigation. The accuracy of cup positioning was better with CT-based navigation than with image-free navigation when the ipsilateral ASIS and L5 spinous process were digitized. However, accuracy was similar when bilateral ASIS points were digitized.

Accuracy of image-free navigation in intraoperative leg length change from total hip arthroplasty using evaluations from 2D and 3D measurements

Background

Leg length discrepancy is one of the most common problems after total hip arthroplasty (THA). The aim of this study was to investigate the accuracy of image-free navigation in intraoperative leg length change (LLC) using evaluations from anteroposterior radiographs (2D measurement) and 3D bone models using CT data (3D measurement).

Methods

One hundred THAs with cementless cups and stems were performed using an image-free navigation system in our hospital. We evaluated the accuracy of image-free navigation based on LLC from 2D and 3D measurements. Furthermore, we also investigated error in absolute value and correlations between 2D and 3D measurements in LLC.

Results

The accuracy of image-free navigation based on 2D measurement was 94% within 5 mm and 76% within 3 mm. The accuracy of image-free navigation based on 3D measurement was 92% within 5 mm and 81% within 3 mm. The error in absolute value in LLC between 2D and 3D measurements was 1.7 ± 1.4 mm (range, 0 to 6 mm). A strong correlation was observed between 2D and 3D measurements in the LLC.

Conclusions

In the present study, good accuracy of image-free navigation in intraoperative LLC was confirmed for both evaluation methods from 2D and 3D measurements. In addition, the error in absolute value in the LLC between 2D and 3D measurements was very small, and we observed a strong correlation between 2D and 3D measurements. Based on these results, evaluation of LLC from radiographs was considered sufficient if radiographs can be taken accurately.

The accuracy of acetabular cup placement in primary total hip arthroplasty using an image-free navigation system

BACKGROUND

Intraoperative navigation systems have been shown to improve the accuracy of acetabular component insertion in total hip arthroplasty (THA). The purpose of this study was to investigate the accuracy of cup orientation in primary THA using an image-free navigation system.

METHODS

A total of 107 consecutive cementless THAs using an image-free navigation system were performed from February 2017 to March 2020 (the navigation group). As a control group, 77 retrospective consecutive cases who underwent THAs with manual implant-techniques between February 2012 and April 2017 were included. Postoperative cup radiographic inclination and radiographic anteversion relative to the functional pelvic plane were assessed using a 3D-template system after computed tomography (CT) examination.

RESULTS

The mean absolute errors of the postoperative measured angles from the target angles in inclination were 3.4° ± 3.0° in the navigation group and 8.4° ± 6.6° in the control group (p < 0.001). The mean absolute errors in anteversion were 5.1° ± 3.6° in the navigation group and 10.8° ± 6.5° in the control group (p < 0.001). The percentage of cups inside the Lewinnek safe zone was 93% in the navigation group and 44% in the control group (p < 0.001). The mean absolute values of navigation error were 3.3° ± 2.8° in inclination and 5.8° ± 4.9° in anteversion. Among the cases of osteoarthritis, the inclination error was significantly higher in Crowe group 2 to 4 than in Crowe group 1 (5.1° ± 3.5° and 3.0° ± 2.5°, respectively, p < 0.05). The percentage of hips with inclination error over 10° in Crowe group 2 to 4 was significantly higher than in Crowe group 1 (17 and 1%, respectively, p < 0.05).

CONCLUSIONS

The image-free navigation system improved the accuracy of cup orientation. The accuracy of cup position was less in Crowe group 2 to 4 than in Crowe group 1.

Possible Neuropathic Pain in Patients with Osteoarthritis of the Knee Before and After Total Knee Arthroplasty

Purpose

Although the pain of osteoarthritis (OA) is traditionally considered to be nociceptive, some patients also have neuropathic pain. The objective of this study was to evaluate the presence of neuropathic pain in the knees of OA patients using the painDETECT questionnaire (PDQ).

Methods

A total of 180 knees in 158 consecutive patients who underwent total knee arthroplasty (TKA) were enrolled prospectively. The prevalence of neuropathic pain, unclear pain, and nociceptive pain in the knee was determined before and after TKA using a numerical rating scale (NRS). All patients were evaluated preoperatively and 6 months postoperatively. Neuropathic pain and unclear pain were grouped together as possible neuropathic pain. The relationship between possible neuropathic pain and pain intensity was evaluated.

Results

Before TKA, neuropathic pain and unclear pain were found in 10 and 30 knees, respectively. The remaining 140 knees were categorized as nociceptive pain. After TKA, the numbers of knees with neuropathic and unclear pain decreased to one and five, respectively. The prevalence of possible neuropathic pain decreased significantly from 22.2% to 3.3% after surgery. Among the six knees with possible neuropathic pain postoperatively, four had possible neuropathic pain preoperatively as well, while the remaining two patients had been classified as nociceptive pain preoperatively. Knees with possible neuropathic pain postoperatively had higher postoperative NRS scores than those with nociceptive pain.

Conclusion

Although the prevalence of possible neuropathic pain decreased significantly after TKA, the preoperative presence of possible neuropathic pain might be associated with the development of persistent postoperative pain following TKA.

The Evaluation of Hemostatic Abnormalities Using a CWA-Small Amount Tissue Factor Induced FIX Activation Assay in Major Orthopedic Surgery Patients

We analyzed the utility for a clot waveform analysis (CWA) of small tissue factor induced FIX activation (sTF/FIXa) assay in patients with major orthopedic surgery (including total hip arthroplasty [THA] and total knee arthroplasty [TKA]) receiving edoxaban for the prevention of venous thromboembolism (VTE). The sTF/FIXa assay using recombinant human TF in platelet-rich plasma (PRP) and platelet-poor plasma (PPP) was performed using a CWA in the above patients to monitor the efficacy of edoxaban administration. Of 147 patients (109 THA and 38 TKA), 21 exhibited deep vein thrombosis (DVT), and 15 had massive bleeding. Increased peak heights of the CWA-sTF/FIX were observed in almost patients after surgery and prolonged peak heights of the CWA-sTF/FIX were observed in almost patients treated with edoxaban. The peak heights and times of the CWA-sTF/FIX were significantly higher and shorter, respectively, in PRP than in PPP. There were no significant differences in parameters of the CWA-sTF/FIXa between the patients with and without DVT or between those with and without massive bleeding. The peak time of CWA-sTF/FIXa were significantly longer in TKA patients than in THA patients on day 1 after surgery. The second derivative peak height of the CWA-sTF/FIXa was significantly lower in TKA patients than in THA patients on day 4. The CWA-sTF/FIX reflected hemostatic abnormalities after surgery and the administration of edoxaban, and the results were better in PRP than PPP. Further studies separately analyzing the THA and TKA subgroups should be conducted.

Minimum ten-year results in revision total hip arthroplasty using titanium fully porous long stem

PURPOSE

The fully porous long stem could be used for diaphyseal locking and achieve bypass fixation in revision total hip arthroplasty (THA). This study evaluated long-term results for fully porous long stems made of titanium alloy in revision THA.

METHODS

Between 2003 and 2010, 45 consecutive femoral revisions were performed using fully porous long stems. Thirty-eight hips had complete clinical and radiographic data for a mean of 13.8 years (range, 10-16.7 years). Femoral bone loss was Paprosky type II in 14 hips, type IIIA in 18 hips, and type IIIB in six hips. Clinical results were analyzed using the Merle d'Aubigné and Postel scoring system. Femoral stress shielding was graded. Radiological loosening of the femoral component was evaluated. Kaplan-Meier survival analysis was performed with revision for any reason as the end-point.

RESULTS

Mean Merle d'Aubigné and Postel score improved significantly from 10.7 before revision to 14.5 at latest follow-up (p < 0.001). Third-degree stress shielding was found in seven hips, and fourth degree in 11 hips. Radiological femoral loosening occurred in one hip, which was revised. Another hip was revised for stem fracture. Kaplan-Meier cumulative survival rate was 94.7% at both ten and 15 years.

CONCLUSION

Although stress shielding is a concern with fully porous stems, this stem was useful in revision THA and provided satisfactory long-term results in hips with Paprosky types II, IIIA, and IIIB.

Reconstruction of patellar tendon rupture after total knee arthroplasty using polyethylene cable

BACKGROUND

Patellar tendon rupture is a devastating complication after total knee arthroplasty (TKA). Different strategies have been used to reconstruct or augment direct repairs.

METHODS

Acute patellar tendon ruptures after TKA were treated using ultra-high molecular weight polyethylene cable (Nesplon cable) for augmentation in four patients. Nesplon cables were inserted anteriorly through the quadriceps just above the patella, and drill holes were placed in the tibial tubercle with one in figure-of-eight fashion and the other in cerclage configuration. Clinical evaluations were performed using range of motion and Knee Society Score at the time of last follow-up. Mean follow-up was 3.5 years.

RESULTS

Postoperatively, mean flexion was 119° and mean extension was 0° in all cases. No knees showed extension lag. Mean knee score was 93.8 and mean function score was 63.8. Infection occurred in one case.

CONCLUSION

Patellar tendon reconstruction with Nesplon cable was favorable with good clinical outcomes.

Minimum 10-Year Follow-Up of Cementless Total Hip Arthroplasty With a 32-mm Cobalt-Chromium Head on Highly Cross-Linked Polyethylene and a Tapered, Fiber Metal Proximally Coated Femoral Stem

BACKGROUND

The clinical and radiographic results of cementless total hip arthroplasty using a 32-mm cobalt-chromium head on remelted highly cross-linked polyethylene (HXLPE) and a tapered, fiber metal proximally coated femoral stem were evaluated at a mean follow-up of 12 years.

METHODS

A total of 57 cementless total hip arthroplasties using remelted HXLPE combined with a 32-mm cobalt-chromium head, and a tapered, fiber metal proximally coated femoral stem were performed from October 2004 to December 2006. Clinical evaluation was performed using the Merle d'Aubigné and Postel scoring system. Standardized anteroposterior and lateral radiographs of the pelvis and femur without weight-bearing were analyzed. Radiographic measurements of two-dimensional femoral head penetration into the polyethylene were performed with a computerized method. The steady-state wear rates were measured based on the radiographs from the first year after surgery to the final follow-up.

RESULTS

The mean Merle d'Aubigné and Postel score improved significantly from 10.7 points preoperatively to 15.6 postoperatively (P < .001). No osteolysis was found around the implant. Stem fixation in all cases showed stable bone ingrowth. Third-degree stress shielding was found in 46% of all stems. The total head penetration rate was 0.05 mm/y, and the steady-state wear rate was 0.01 mm/y. The Kaplan-Meier survivorship with the end point of revision was 95% (95% confidence interval, 85%-98%) at 12 years.

CONCLUSION

A 32-mm cobalt-chromium head on remelted HXLPE demonstrated low wear properties, and a tapered, fiber metal proximally coated femoral stem showed good results at long-term follow-up.

Use of antibiotic-impregnated hydroxyapatite for infection following total knee arthroplasty

OBJECTIVES

Antibiotic-impregnated hydroxyapatite (HA) is an emerging drug delivery system for the treatment of periprosthetic joint infection (PJI) of the knee. The aim of this study was to evaluate the clinical results of this treatment in patients with PJI following total knee arthroplasty (TKA).

METHODS

Participants comprised 14 consecutive patients with PJI of the knee who were scheduled to undergo two-stage knee revision. In the first stage, all components were removed with thorough debridement, and antibiotic-impregnated HA was inserted in the bone and joint space. In the second stage, revision TKA was performed after the eradication of infection. The mean period from the removal of all components and treatment with antibiotic-impregnated HA to revision TKA was 3.4 months. Clinical and radiographic evaluations were performed after a mean follow-up of 6.1 years following revision TKA. Predictors of reinfection were evaluated.

RESULTS

Eleven patients had no recurrent infection, whereas 3 patients showed recurrent infection. Knee Society knee score and function score, as well as flexion angles, improved significantly postoperatively. No knees showed osteolysis or loosening after revision TKA. The present study identified no predictors of reinfection.

CONCLUSION

Antibiotic-impregnated HA could be effective in treating knee PJI.

Thirteen-year results of cementless total hip arthroplasty with zirconia heads on highly cross-linked polyethylene

OBJECTIVES

Zirconia ceramic was introduced for femoral heads because of its mechanical strength and fracture toughness. Highly cross-linked polyethylene has been shown to achieve wear reduction compared to conventional polyethylene. The purpose of this study was to investigate the long-term results of cementless total hip arthroplasty with zirconia femoral heads on highly cross-linked polyethylene.

METHODS

Radiographic measurements of two-dimensional femoral head penetration into the polyethylene were performed with a computerized method (PolyWare) in 93 hips at a mean follow-up of 13 years. The steady-state wear rates were measured based on the radiographs from the first year after surgery to the final follow-up.

RESULTS

The mean Merle d'Aubigné and Postel score had improved significantly from 10.9 points preoperatively to 15.3 postoperatively (p < 0.001). Osteolysis was not found around the implant, and no zirconia heads had fractures. The total head penetration rate was 0.04 mm/year, and the steady-state wear rate was 0.02 mm/year. Kaplan-Meier survivorship with the endpoint of revision was 97% (95% confidence interval [CI], 92% to 99%) at 10 years.

CONCLUSION

Zirconia on highly cross-linked polyethylene demonstrated extremely low wear properties at long-term follow-up.

Accuracy of acetabular cup insertion in an anterolateral supine approach using an accelerometer-based portable navigation system

The purpose of this study was to determine the accuracy of acetabular cup insertion during total hip arthroplasty (THA) in a supine position using an accelerometer-based portable navigation system. A single-surgeon study was conducted in which 62 prospective patients with navigation and 42 retrospective patients without navigation as historical controls were compared. The patients underwent THA via an anterolateral supine approach. The absolute values of errors of radiographic inclination and anteversion were calculated. The navigation error was also calculated. The factors that affected the absolute values of errors of cup alignment were determined. The mean absolute error of the postoperative CT measurement from the target angle for radiographic inclination was 3.8° in the navigation group and 6.6° in the control group (P < 0.001). The mean absolute error for anteversion was 3.3° in the navigation group and 5.9° in the control group (P < 0.001). The mean absolute values of navigation error were 3.7° ± 2.8° in inclination and 3.0° ± 2.6° in anteversion. Changes in the pelvic tilt angle among preoperative, intraoperative, and postoperative were the significant risk factors for the absolute values of navigation error of anteversion relative to the anterior pelvic plane. Other factors affecting the absolute values of errors in the navigation group were not found for radiographic inclination and anteversion. The portable navigation system significantly improved the accuracy of cup inclination and anteversion. Changes in the pelvic tilt were the risk factors for the error of anteversion relative to the anterior pelvic plane.

Prevalence of Persistent Pain after Total Knee Arthroplasty and the Impact of Neuropathic Pain

The present study aimed to define the prevalence of pain persisting after total knee arthroplasty (TKA) and determine the impact of neuropathic pain. Knee pain after TKA was evaluated in 154 patients (222 knees with osteoarthritis) using a numerical rating scale (NRS) and followed up for a mean of 4.7 years. The patients were classified according to whether they had no or mild pain (NRS ≤ 3), or moderate-to-severe pain (NRS > 3), and then assigned to groups with nociceptive, unclear, or neuropathic pain based on responses to painDETECT questionnaires. Risk factors for these types of pain were determined. The ratio of patients with moderate-to-severe pain was 28% (62 knees). Thirteen patients (21 knees; 9%) experienced unclear pain. Patients with moderate-to-severe or unclear pain had malalignment and lower Knee Society knee scores. In conclusion, a significant number of patients experienced moderate-to-severe and unclear pain after TKA. Moderate-to-severe pain was associated with unclear pain.

Surface modifications and oxidative degradation in MPC-grafted highly cross-linked polyethylene liners retrieved from short-term total hip arthroplasty

Highly cross-linked polyethylene (HXLPE) hip liners grafted with 2-methacryloyloxyethyl phosphorylcholine (MPC) on their bearing surfaces have recently been commercialized as components of a new generation of artificial hip joints, while improvements in wear resistance and biocompatibility were reported based on in vitro studies. The present study aimed at evaluating the surface modification and oxidative degradation in short-term retrieved MPC-grafted liners by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR) with attenuated total reflection (ATR) equipment and Raman spectroscopy. In none of 3 samples of retrieved MPC-grafted liners, detectable MPC graft remained on the bearing surfaces although 2 samples yet contained remains of MPC polymer in their rim zone. These results revealed that the MPC polymer might have quickly disappeared from the bearing surface under in vivo loading, which is more severe than the in vitro one. Furthermore, a detectable oxidation index (OI) value (>0.1) was not only observed in any zone of any sample investigated, but also in the rim zones of Samples 1 and 2, which surprisingly experienced the most remarkable increase in OI value detected in this study. We thus confirmed that: (i) annealing of HXLPE cannot completely remove free radicals; (ii) the MPC graft has no beneficial effect in protecting HXLPE against oxidation and wear; and, (iii) lipid absorption occurred even in the rim zone where the MPC layer remained. Based on these evidences we consider that the declaimed advanced MPC technology is not a suitable one to elongate the in vivo lifetime of hip joints.

STATEMENT OF SIGNIFICANCE

Several studies reported that highly crosslinked polyethylene (HXLPE) have resulted in reduced wear in total hip arthroplasty. Beyond those studies, HXLPE hip liners grafted with 2-methacryloyloxyethyl phosphorylcholine (MPC) on their bearing surface were extensively studied in vitro and then commercialized as a new generation of artificial hip joints. The present study reports for the first time results about the evaluation of surface modification and oxidative degradation in retrieved the MPC grafted liners. The findings of this investigation clearly show that the MPC layer has been peeled off on the bearing surface of the liner main wear zone although the MPC layer remained on the surface of the rim zones. Furthermore, we assessed the microstructural modifications and the oxidation drifts that occurred in vivo in the hip joints despite the presence of the MPC layer.

Comparison of three different anti-Xa assays in major orthopedic surgery patients treated with direct oral anticoagulant

Background

Measurement of edoxaban plasma concentration has been gathering attention in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE).

Methods

The anti-Xa activity was measured one hour after edoxaban intake using 3 different assays in 200 patients after major orthopedic surgery.

Results

The anti-Xa activities on Day 8 were significantly higher than those on Day 4 and those on Day 4 were significantly higher than those on Day 1. The anti-Xa activities in two assays closely correlated with each other, but the other anti-Xa assay did not correlated with other two assays. The anti-Xa activities as detected in the three Xa assays were significantly higher in the patients without deep vein thrombosis (DVT) than in those with DVT on Day 4. Additionally, there were no significant differences in the anti-Xa activities of assays A, B and C between patients with and without massive bleeding (MB) on Days 1, 4, 8 and 15.

Conclusion

The results of this study suggest that anti-Xa level could be predictive of the risk of VTE, but not of the risk of massive bleeding.

Monitoring of hemostatic abnormalities in major orthopedic surgery patients treated with edoxaban by APTT waveform

INTRODUCTION

An analysis of the activated partial thromboplastin time (APTT) in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE) was carried out.

METHODS

The APTT waveform was analyzed in the above patients to monitor edoxaban administration.

RESULTS

Of these 99 patients, 12 exhibited deep vein thrombosis, and 25 had massive bleeding. An increased biphasic pattern of the APTT waveform was observed after the administration of edoxaban, but there were no significant differences between the patients with and without complications. The peak times of acceleration, velocity, and 1/2 fibrin formation were significantly prolonged after the administration of edoxaban, especially in patients with massive bleeding, and were moderately correlated with the anti-Xa activity. While the heights of velocity and acceleration peak 2 were lower in patients receiving warfarin treatment than in those receiving edoxaban, the widths of these parameters were significantly longer. The height of 1/2 fibrin formation and the width of acceleration peaks 1 and 2 and the velocity were significantly increased after the administration of edoxaban.

CONCLUSION

The peak time of the APTT waveform was significantly prolonged after the administration of edoxaban. The analysis of the APTT waveform may therefore be useful for the prediction of the risk of massive bleeding.

Validation of a protocol based on Raman and infrared spectroscopies to nondestructively estimate the oxidative degradation of UHMWPE used in total joint arthroplasty

As a matter of fact, the in vivo oxidative degradation of highly cross-linked polyethylene (HXLPE) still remains one of the limiting factors that affect the long term survivorship of joint replacements. Recent studies clearly pointed out that also the new generation of highly cross-linked and remelted polyethylene components in total hip and knee replacement underwent unexpected oxidation after 5-10years of implantation. The standard methodology to investigate the oxidation of polyethylene (PE) relies on the use of infrared spectroscopy, which, if from one hand is a reliable technique for the detection of oxidized species containing carbonyl group, on the other hand it is not capable of discriminating the fraction of carboxyl acids that is responsible for chain scission and subsequent deterioration of the mechanical properties of the polymer. In the present study we validate a new protocol based on Raman spectroscopy, which is suitable on assessing the structural degradation of polyethylene induced by oxidation. Following in vitro accelerated aging experiments, the oxidation index (OI) of different commercially available HXLPEs, as calculated by infrared spectroscopy according to ASTM standard, has been univocally correlated to the most severe variation of crystalline phase (αc), as calculated by Raman spectroscopy. In each material, locations with equal values of OI showed different degree of recrystallization induced by chain scission, confirming that infrared spectroscopy might overestimate the effective mechanical degradation of the polymer. In addition, as compared to the standards based on infrared spectroscopy, this new method of assessing oxidation enables to investigate the degradation occurring on the original surface of HXLPE components, due to the nondestructive nature of Raman spectroscopy and its high spatial resolution.

STATEMENT OF SIGNIFICANCE

In the present study we validate a new protocol based on Raman spectroscopy, which is suitable on assessing the structural degradation of polyethylene induced by oxidation. In fact, the standard methodology to investigate the oxidation in polyethylene relies on the use of infrared spectroscopy, which is capable of detecting the presence of oxidized species containing carbonyl group, the main products of oxidation in polyolefins. If from one hand this technique enables quantitative analysis of oxidation, on the other hand it is not capable of discriminating the fraction of species with carbonyl groups responsible for the chain scission. In fact, esters, ketones and carboxyl acids are products of oxidation with carbonyl groups commonly formed on polyethylene at the end of the oxidative cascade initiated by the presence of free radicals, but only the latter are responsible for the chain scission and the subsequent deterioration of the mechanical properties. The oxidation index as obtained according to the ASTM standards is not univocally correlated to a certain degree of mechanical deterioration, but, in simple words, two retrievals with the same amount of carbonyl groups might have had different degradation of the mechanical properties. Recrystallization is a direct consequence of the reduction of molecular weight that occurs after chain scission. Raman spectroscopy (RS) is a viable non-destructive method to assess the fraction of crystalline phase in polyethylene and, due to its high spatial resolution, is perfectly suitable to analyze the microstructural modification at the mesoscopic scale, where the effects of oxidation manifest themselves. The aim of the present paper is twofold: i) to compare the microstructural modifications caused by in vitro oxidation on 5 different types of polyethylene currently available on the market of joint replacements; ii) to establish a protocol based on the comparative analysis of IR and RS results to obtain a phenomenological correlation capable to judge the mechanical deterioration of the material induced by the oxidative degradation.

Serum macrophage migration inhibitory factor (MIF) levels after allogeneic hematopoietic stem cell transplantation

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), as MIF plays an important role to regulate the production of tumor necrosis factor-alpha (TNF-alpha), one of the inflammatory cytokines which induces and exacerbates aGVHD. We examined the association between serum MIF levels and aGVHD vs. chronic GVHD (cGVHD) in allo-SCT patients in this study. We found a significant increase in the peak serum MIF (14.46 ng +/- 1.47 ng/ml) at onset in patients that developed aGVHD (n = 23, P = 0.009). We also found that mean serum MIF levels in patients who developed extensive type cGVHD within 6 months (12.58 +/- 2.18 ng/ml, n = 13) were significantly higher than MIF levels before allo-HSCT (7.86 +/- 1.17 ng/ml, n = 19, P = 0.04). Therefore, we speculated that serum MIF levels increase during the active phase of both aGVHD and cGVHD.

Valuation of growth parameters in monolayer keratinocyte cultures based on a two-dimensional cell placement model

The influence of inoculum size on the growth of keratinocyte cells was investigated in a monolayer culture with serum-free medium. A growth model of cell placement was applied to the expression of the cell adhesion phase after the inoculation, lag phase, exponential growth phase, and stationary phase because of contact inhibition at high cell densities. Based on the model, the lag time until the onset of cell division was shortened in proportion to the logarithm of the inoculum cell size, resulting in the enhancement of overall cell propagation. It was verified that the proposed model is valid for the determination of the optimal inoculum size to realize the efficient growth of keratinocytes, indicating that the model is a useful tool to predict an optimal culture scheme for the production of skin grafts.

Indoleamine 2,3-Dioxygenase is Necessary for Cytolytic Activity of Natural Killer Cells

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan catabolic enzyme that is widely distributed in various tissues. In peripheral blood mononuclear cells (PBMCs), production of IDO by macrophages or dendritic cells has been reported to inhibit T-cell activation and proliferation. In the present study, we have determined that other phenotypes of PBMCs also express IDO. In cultures of PBMCs, IDO was found predominantly in monocyte by immunohistochemistry. Reverse transcriptase polymerase chain reaction analysis showed that IDO mRNA was expressed in T lymphocytes, B lymphocytes and natural killer (NK) cells and that expression was increased upon activation with interferon-gamma. The cytotoxicity of NK cells against K562 and HepG2 cells was reduced by IDO inhibitor. These results suggest that IDO in NK cells is essential for NK cells to generate killing activity against cancer cells.

Transcriptional suppression of the estrogen receptor by truncated estrogen receptor-alpha

The estrogen receptor (ER) is composed of six major functional domains - the A/B domain as the activation function 1 domain, domain C as the DNA-binding domain, domain D as a hinge domain, and domain E/F as the ligand-dependent transcriptional domains. A novel protein (designated as SRB-RGS) that interacted with domains C and D of ER alpha (ER alpha C/D) repressed the transcriptional activity of ER alpha. In this study, we have examined whether ER alpha C/D releases transcriptional suppression of ER alpha by intrinsic SRB-RGS. The expression vector of ER alpha C/D was transfected to the human cancer cell, KPL-1, which expressed the intrinsic ER. Unexpectedly, transcriptional suppression of ER by ER alpha C/D was observed. COS-7 cells, which have no intrinsic ER, showed a similar suppression of ER alpha by co-transfection of ER alpha and ER alpha C/D. The DNA-binding and the estrogen-binding activities of ER alpha decreased on co-transfection of ER alpha C/D, suggesting a decrease in the receptor protein itself. It is likely that the degradation of ER by co-transfection caused the transcriptional suppression of the ER.

CAD/DFF40 nuclease is dispensable for high molecular weight DNA cleavage and stage I chromatin condensation in apoptosis

DNA degradation during apoptotic execution generally occurs at two levels: early as high molecular weight (HMW) fragments and later on as oligonucleosomal fragments. Two nucleases, CAD/CPAN/DFF40 and endonuclease G, can digest nuclear chromatin to produce the oligonucleosomal fragments, and it has been suggested that CAD might be responsible for HMW DNA cleavage. To more clearly define the role of CAD in nuclear disassembly, we have generated CAD(-/-) sublines of chicken DT40 cells in which the entire CAD open reading frame has been deleted. These cells grow normally and undergo apoptosis with kinetics essentially identical to wild type cells. However, they fail to undergo detectable oligonucleosomal fragmentation, proving that CAD is essential for this stage of DNA cleavage, at least in DT40 cells. Other aspects of nuclear disassembly, including HMW DNA cleavage and early stage apoptotic chromatin condensation against the nuclear periphery proceed normally in the absence of CAD. However, the final stages of chromatin condensation and nuclear fragmentation do not occur. Our results demonstrate that CAD is required for complete disassembly of the nucleus during apoptosis and reveal the existence of one or more as yet unidentified second factors responsible for HMW DNA cleavage and the early stages of apoptotic chromatin condensation.