Indian Knees Research Articles

CT Morphometric Analysis of the Medial Femoral Condyle in an Indian Population: A Comparative Study of Unicompartmental Knee Arthroplasty Implants.

Purpose The objective of this study was to evaluate the compatibility of the medial femoral condyle (MFC) dimensions in the Indian population with the standard femoral components of three commercially available unicompartmental knee arthroplasty (UKA) implants. Methods This analytical study utilized CTmorphometric data from 100 consecutive non-arthritic adult knees. MFC dimensions were measured to assess their compatibility with UKA prostheses. The proportion of knees that could be optimally replaced using three commercially available UKA femoral implant systems, Link, DePuy, and Smith & Nephew, was calculated. Results The study cohort comprised 56 males and 44 females, with a mean age of 43.28 ± 10.53 years. For the Link implant system, the 'small' size was the most compatible, fitting 43% (43) of the patients, followed by 'medium-small' (35%, n = 35) and 'medium' (16%, n = 16). For the DePuy Sigma Uni implant, the best fit was 'size 1' for 38% (38) of the patients, followed by 'size 3' (25%, n = 25), 'size 4' (13%, n = 13), 'size 2' (10%, n = 10), and 'size 5' (2%, n = 2). In the case of the Smith & Nephew system, 'size 2' was the best fit for 30% (30) of the knees, followed by 'size 3' (27%, n = 27), 'size 4' (15%, n = 15), 'size 1' (12%, n = 12), and 'size 5' (8%, n = 8). Overhang of the femoral component, due to the MFC being smaller than the smallest available femoral component size, was observed in 6% (6) of knees with Link implants, 12% (12) with DePuy implants, and 8% (8) with Smith & Nephew implants. Conclusion The findings indicate that the most suitable femoral component sizes for Indian knees were 'small' in the Link system (43%, n = 43), 'size 1' in the DePuy system (38%, n = 38), and 'size 2' in the Smith & Nephew system (30%, n = 30). The results suggest a need for implant manufacturers to consider developing customized components tailored to the Indian population to enhance fit and minimize the occurrence of femoral component overhang.

Radiological Study of Ossified Fabella in Indian Knees: A Cross-sectional Study

Radiological Study of Ossified Fabella in Indian Knees: A Cross-sectional Study

Coronal Plane Alignment of Knee Joint (C.P.A.K.) Classification in Indian Population- Study of A New Classification System in Indian Knees

Background: Distribution of CPAK types in Indian knees will help surgeons better understand management of knee arthritis using concept of Kinematic alignment (K.A.). C.P.A.K. uses a matrix of 9 phenotypes of knees based on arithmetic hip knee ankle angle (aHKA) and Joint Line Obliquity (JLO). Methods: A radiological analysis of 200 healthy knees (HC) and 250 osteoarthritic knees (OC) was done and were classified based on C.P.A.K. classification. Primary outcomes include descriptive analysis of both groups, and comparison between frequencies of types within each group. Results: The commonest CPAK types in Healthy group were type 5, type 2, type 1. For arthritic group, common types in order were type 1, type 4 and type 2. Varus CPAK types (1,4,7) accounted for 34% of HC types while 59% of OC type, with odds of developing osteoarthritis in type 1 CPAK being 2.84 while that for type 4 were 2.02. Out of 450 knees studied 216 (48%) accounted for varus alignment. Conclusion: C.P.A.K. classification can be used to understand the targets for TKR in Indian population. Constitutional varus being commoner in Indian knees (48%) than their western counterparts implies that majority of Indian knees are in constitutional varus dynamics, hence K.A. caters to majority of the population. Arthritic Indian populations are predominantly of types C.P.A.K. 1(34%) and 4(22%). Further research is needed to understand which Indian knee types benefit the most from KA TKR.

Does One Size Really Fit All? Morphometric Analysis of Distal Femur and Proximal Tibia in an Ethnic Indian Population and Correlation to the Sizing of Existing Total Knee Arthroplasty Implants.

Total knee arthroplasty (TKA) has been proven to be a highly efficacious procedure for patients with end-stage osteoarthritis who have persistent symptoms not managed by conservative treatment. A large percentage of standard commercially available total knee arthroplasty (TKA) implants are imported and designed based on morphometric data of Western populations, which are known to have a larger build compared to their Asian counterparts. Hence, these prostheses may sometimes not be the best fit for Indian patients. We conducted this study to examine the anthropometry of osteoarthritic knees of Indian patients, analyze anatomical differences between males and females, and compare these measurements with commercially available five TKA implants. Morphometric data were collected from 150 Indian patients with osteoarthritis of the knee using computed tomography (CT) scans. The mediolateral (ML) and anteroposterior (AP) dimensions of the distal femur and proximal tibia were measured, and aspect ratios (ML/AP) were calculated. These measurements were correlated with current commercially available implant sizes. We examined CT scans of100 female and 50 male patients' knees with a combined average age of 58.2 ± 7.5 years. The mean mediolateral and anteroposterior dimensions of the distal femur for Indian knees were 74.5 ± 5.8 mm and 58.0 ± 4.2 mm, respectively, whereas for the proximal tibia, 69.1 ± 5.5 mm and 43.8 ± 3.6, respectively. The mean aspect ratio for the femur was 129.0 ± 6.0 and for the tibia was 158.1 ± 9.1. Male dimensions were found to be greater than female dimensions in all measured aspects of the distal femur and proximal tibia for the Indian population. However, the aspect ratio of the tibia was not found to vary with gender. When compared with the dimensions of other ethnic groups, the size of Indian knees was found to be smaller than Caucasians. There is a mismatch between the anatomy of Indian knees and currently available TKA implants, and these implants may have drawbacks when implanted in Indian patients. The obtained anthropometric data may provide useful directions for designing TKA implants of more suitable sizes and aspect ratios for Indian patients.

CT Morphometric Analysis of Medial Tibial Condyles: Are the Currently Available Designs of Unicompartmental Knee Arthroplasty Suitable for Indian Knees?

The main purpose of this study is to assess the compatibility of medial tibial condyle (MTC) morphometry of Indian population with that of six contemporary UKA prostheses tibial components. We hypothesized that from the currently available UKA designs at least one would fit the MTC morphometry optimally as per the manufacturer's recommendation. We used CT morphometric data of 100 (66 males and 34 females) consecutive nonarthritic adult knees with reference to the MTC to assess the compatibility of currently available (in India) UKA prostheses. Each MTC was measured in the anteroposterior dimension, mediolateral at pre-defined points and the MTC aspect ratio calculated. Proportion of knees which could be optimally fitted with the existing UKA tibial components was calculated. The mean age was 39.6 (SD 15.9) years. Anteroposterior and mediolateral dimensions in males were higher as compared to females (p < 0.001). As the anteroposterior dimension increased, the MTC aspect ratio decreased. There was asymmetry of anteroposterior halves with maximum mediolateral width being posterior to the central mediolateral width by 5.5 (SD 2.8) mm. Optimal anteroposterior fit ranged from 66 to 93%. However, optimal mediolateral fit as well, ranged from 5 to 37% with underhang present in 17-61% and > 2mm medial overhang present in 0-35% cases. In 23% of cases, not a single implant could be fitted optimally. Currently available UKA implants do not provide optimal tibial fit in nearly 25% of Indian patients. A surgeon needs to be aware of these limitations of existing implants when considering UKA.

Is Flexion Gap Rectangular in Native Indian Knees? Results of an MRI Study.

The purpose of this study was to evaluate the flexion-gap of the native knees in the normal population and to assess any gender-specific variations in the flexion gap of the knees. A total of 50 normal asymptomatic volunteers with normal knee radiographs were selected for MRI of the knee. The left knee was scanned in an open MRI using a T1-weighted sequence. Imaging was performed in neutral, passive varus and valgus stress at 90° of knee flexion by placing custom-made blocks on a special board consecutively below the distal part of the leg. The study population consisted of 26 males and 24 females with a mean age of 25.77years. Under varus stress, the mean lateral flexion gap increased to 9.28 ± 1.53mm and under valgus stress, the mean medial flexion gap increased to 2.75 ± 1.22mm from neutral. The increase in the flexion gap on the lateral side was 5.28 ± 1.79mm, which was significantly higher compared to that on the medial side. In gender-specific analysis, the mean lateral flexion gap was 10.21mm in females and 8.46mm in males under varus stress. The findings of the study indicate that the lateral soft tissues are more lax compared to the medial soft tissue structures and this laxity is higher in females as compared to males. The study provides evidence of the existing physiological variations of these soft tissue structures resulting in a trapezoidal flexion gap in the native knees rather than the recommended rectangular gap.

Clinical evaluation of low cost Indian knee prosthesis in government medical colleges

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The clinical and functional outcome of total knee arthroplasty was studied using low cost Indian knee prosthesis called Destiknee by Maxx Company in government medical hospital. The objectives was to do assessment of pain relief, joint mobility and deformity correction post-operatively, pre-operative and post-operative Knee society score comparison.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Patients included were those who underwent primary total knee arthroplasty in Department of Orthopaedics, GMCH Aurangabad from January 2020 to January 2021. Clinical and functional assessment was done using the Knee society score and x-rays at 3, 6 and 12 months intervals.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; At 1 year follow up of 28 knees, there was an improvement in the average pre-op Knee society score of 53.92 to average post-op score of 86.25 and in the range of motion from 80.42 degree to 127.32 degrees and knee flexion deformity improved from 15.25 degrees to 2.17 degrees, all of which had a p value&amp;lt;0.05 are significant statistically. One diabetic patient with poor glycemic control had superficial infection and one developed minor pulmonary embolism which recovered with medical management. Patients had good satisfaction both in unilateral and bilateral TKA.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; TKA resulted in significant reduction in knee pain and improvement in the functional ability of patients. The results of this low cost Indian prosthesis in a government rural setup with no laminar airflow with good efficacy and minimal complications are excellent. It was a boon for the rural population suffering from knee pain.&lt;/p&gt;

Sexual dimorphism and racial diversity render bone-implant mismatch inevitable after off-the-shelf total knee arthroplasty: a systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to investigate the variability in femoral geometric ratios among knees of different sexes and races, and to appreciate whether the observed variability is accommodated by commonly implanted total knee arthroplasty (TKA) components. The hypothesis was that the anthropometric studies report considerable variability of femoral geometric ratios among sexes and races. This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) criteria. Two authors independently conducted an electronic search using MEDLINE® and Embase® on 6 July 2020 for clinical studies reporting on femoral geometric ratios among sexes and races. Femoral geometric ratios were graphically represented as means and 2 standard deviations, and compared to those of 13 commonly implanted femoral components. A total of 15 studies were identified that reported on a combined total of 2627 knees; all reported the aspect ratio, and 2 also reported the asymmetry ratio and trapezoidicity ratio. Men had wider knees than women, and compared to Caucasian knees, Arabian and Indian knees were wider, while East Asian were narrower. There were no differences in asymmetry ratio between men and women, nor among Caucasian and East Asian knees. Men had more trapezoidal knees than women, and East Asian knees were more trapezoidal than Caucasian knees. The commonly implanted femoral components accommodated less than a quarter of the geometric variability observed among sexes and races. Anthropometric studies reported considerable sexual dimorphism and racial diversity of femoral geometric ratios. Since a surgeon generally only uses one or a few TKA brands, bone-implant mismatch remains unavoidable in a large proportion of knees. These findings support the drive towards personalized medicine, and accurate bone-implant fit may only be achievable through customisation of implants, though the clinical benefits of custom TKA remain to be confirmed. IV.

Western-designed total knee implants mismatch Saudi patient knees. Anatomical bony measurements documented by computed tomography.

Objectives:To determine the anthropometric features of Saudi knees compared with knees of other ethnicities and reveal mismatches among different knee implant systems.Methods:All knee computed tomography images obtained between January 2016 and September 2016 for varying medical reasons in a tertiary care hospital in Southwestern Saudi Arabia were retrospectively evaluated. Patients aged <18 years, with trauma or soft tissue or bone tumors were excluded. Eleven parameters were measured for each knee joint.Results:We evaluated 100 knees of 50 Saudi patients (25 men, 25 women) aged 28-85 (mean, 57.3) years. No statistically significant differences were found in age and Sasaki angle measurements between male and female patients. All other parameters were significantly larger in male than female knees. Our measurements were close to those published for Chinese, Thai, and Korean patients; however, published measurements were larger for Caucasian and Indian knees than our measurements.Conclusion:The Saudi population has morphological features of knee bone anatomy that do not match with the widely available prostheses designed for Caucasian knees. As several studies of different ethnicities have documented considerable prosthesis mismatch; our study further indicates the need for new implant designs that take these variations into account.

Anthropometric Comparison between Indian and Arabian Knees with Respect to Total Knee Replacement.

Implants used for total knee replacement (TKR) in most Asian countries are not designed originally for the Asian population, and studies have shown anthropometric differences with respect to TKR among various ethnic groups. For this reason, implants designed for a specific population may not provide an anatomic fit when used in other populations. To avoid the consequences associated with such a misfit, the concept of ethnic-specific implant design is being introduced. In this study, the knee anthropometry of the Indian and Arabian patients was compared. They were operated with implants which were not ethnic-specific designs. Since the consequences associated with implant misfit apply equally to both the Indian and Arabian population, it is essential to compare the knee anthropometry of these two populations. Anthropometric measurements of the distal femur and proximal tibia of the Indian and Arabian knees were obtained intraoperatively using a Vernier caliper. Their respective aspect ratios (ARs) were calculated and statistically compared. It was found that the ARs of both tibia and femur of Indian and Arabian population did not show any statistical difference. There was no statistical difference between Indian and Arabian males (p = 0.345) and between Indian and Arabian females (p = 0.8210). However, a statistical difference in tibial AR (p-value = 0.049) and femoral AR (p-value = 0.003) was found significant when a comparison was made between the knees of Indian males and Indian females in the study. The above results suggested that TKR implants designed anatomically to suit the Indian population can also suit the Arabian population and vice versa. The obtained data can help implant designers to come up with ethnic-specific TKR implants.

Anthropometry of Nonarthritic Asian Knees: Is It Time for a Race-Specific Knee Implant?

BackgroundThis study was done to study the anthropometry of nonarthritic Asian knees; to determine the differences in morphology between knees of different ethnicities and to compare the knee anthropometry values with sizes of available knee implants.MethodsMagnetic resonance imaging scans of 100 nonarthritic Indian knees were analyzed. Anteroposterior (AP) length, mediolateral (ML) length, and aspect ratio of the distal femur and proximal tibia, patellar length, and patellar tendon length were measured. These values were compared with values of other ethnicities from literature. The values were also compared with sizes of available knee implants and evaluated for mismatch.ResultsAll the parameters of female knees were significantly smaller than those of male knees (p < 0.05). The distal femur of Indian knees resembled that of Chinese knees with similar AP and ML lengths and aspect ratio. The distal femur of Indian knees had a significantly smaller AP, ML, and aspect ratio than those of Hispanic knees did. In comparison to Caucasian distal femur, Indian knees had smaller AP and ML lengths and larger aspect ratio. In terms of the proximal tibia, the Indian knees were smaller than Chinese (only ML), Caucasian (AP and ML) and Hispanic (AP and ML) knees. On comparison with implant sizes, there was a mismatch between the distal femur morphology and the dimensions of all implants. For a given AP length, the ML dimensions of all implants were smaller than the measured ML length of the knee. However, the tibial components of all the studied implants correlated well with the tibial morphology.ConclusionsDistinct anthropometric differences exist between knees of different ethnicities. The knees of females were smaller than the knees of males. In Indian knees, the ML-AP aspect ratio of the distal femur was higher than that of the currently available femoral components. These results suggest the need for race-specific knee implants.

Computed Tomography-based Analysis of Tibial Tuberosity-Trochlear Groove Distance in Indian Population.

AimTo study the tibial tuberosity-trochlear groove distance (TT-TG) in normal Indian population and the variation of the same in relation to tibial size using computed tomography (CT) of knee.MethodsCT of 100 knees (62 males and 38 females) were assessed. TT-TG distance and maximal medio-lateral (MML) distance of tibia was measured on axial CT scans. The modified TT-TG (mTT-TG) was calculated as the ratio of TT-TG and MML.ResultsThe average TT-TG distance was 13.01 (±2.84) mm for the entire group with males and females having 12.82 (±2.95) and 13.32 (±2.66) mm, respectively (p > 0.05). The MML distance was 75.99 (±3.78) and 66.77 (±4.33) mm for males and females, respectively (p < 0.05). The average modified TT-TG was 0.18 ± 0.04. The TT-TG distance of Indian knees was similar to values obtained in Caucasian knees and higher than other Asian knees (p < 0.05).ConclusionThe average TT-TG distance in Indian population is 13.01 mm, with no difference between males and females. The ML/TT-TG ratio was 0.18. The TT-TG distance in Indian population is found to be similar to the Western population and significantly higher than other Asian population.

Comparative study of existing knee prosthesis with anthropometry of Indian patients and other races, a computer tomography 3D reconstruction-based study

Background: Appropriate component sizing plays an important role in determining the functional outcome following total knee arthroplasty. Comparative studies of different populations have shown significant differences in the anthropometric parameters of knees in different race groups which negates the possibility of using a single sized implant system across different ethnic groups. This study evaluates the dimensions of femoral and tibial articular surfaces of Indian patients and compares the parameters with other ethnic groups and correlates the dimensions with five different commercially available knee systems.Material & Methods: Computerized tomography (CT) scans of contralateral normal knees of patients who underwent the scan for various ailments of the knee were retrieved retrospectively from the hospital database and 3D reconstruction of the images was done. Mediolateral dimensions (fML,tML), Anteroposterior dimensions (fAP, tAP) and aspect ratio (fML/fAP, tML/tAP) of the femur and tibia respectively were calculated and compared with the dimensions of different ethnic groups as well as the femoral and tibial components of five different knee prosthesis systems. ResultsThe average fML in the study group was less than that of Caucasian knees but was marginally larger than other ethnic groups. The fAP, tML and tAP was found to be smaller than all other ethnic groups but a larger femoral aspect ratio was reported than other ethnic groups. Among the implant systems, only NexGen LPS and Scorpio NRG implant femoral components closely matched the femoral dimensions in the study group whereas all implant systems showed significant mismatch with tibial component dimensions when compared to the study populations. ConclusionThis study concludes that the dimensions of Indian knees are different from other ethnic groups and the use of commercially available knee Implants designed based on measurements in Caucasian populations can lead to significant mismatch between implant and resected bone surfaces.

Anatomy of posterior cruciate ligament retained in a posterior cruciate ligament retaining total knee replacement: a cadaveric study.

Background: Recent evidence has highlighted a risk that the majority of posterior cruciate ligament (PCL) is removed while making bone cuts in tibia and femur during total knee replacement surgery. Aim of this cadaveric study is to calculate how much PCL footprint is retained in a PCL retaining prosthesis after routine tibial and femoral cuts are made. Methods: Twelve paired formalin-fixed Indian cadaveric knees were studied. Knees were disarticulated and all soft tissues were circumferentially removed from the tibia and femur. Footprints of antero-lateral and postero-medial bundles were marked on tibia and femur. Proximal tibial and distal femoral cuts were made using standard cutting jigs (Zimmer NexGen LPS). Digital photographs were taken with a magnification marker attached on the bone before and after making the cuts. Area of PCL insertion before and after the bone cuts was measured using software ImageJ (National Institute of Health).Results: Footprint on tibial side was reduced by 9.1%, and on femoral side by 21.8%. Footprint of AL bundle was reduced by 24.3% on the tibial side and by 15.3% on the femoral side. Footprint of PM bundle on tibia was not affected by the bone cut but was reduced by 18.5% on the femoral side.Conclusion: Tibial and femoral insertions of PCL are relatively well preserved after bone cuts are made in a posterior cruciate retaining TKR. There is differential sectioning of antero-lateral and postero-medial bundles of PCL on tibial and femoral sides.

Anthropometric assessment of tibial resection surface morphology in total knee arthroplasty for tibial component design in Indian population

IntroductionAn anthropometrically well designed knee prosthesis that matches properly to the resected surface of the bone is key for long term survivorship in TKA. AimThe aim of the study was to make an anthropometric analysis at resected surfaces of proximal tibia in Indian population and to compare it with the available data of other ethnicities. Methods- CT scans of 50 subjects were used to select the tibial resection surface. The surface selection was virtually done on each tibia at 8mm off the lateral plateau using Micro Dicom system (reflecting a 10-mm surgical cut assuming a cartilage thickness of 2mm). We measured the mediolateral, middle anteroposterior, medial and lateral anteroposterior dimensions, the aspect ratio and asymmetry metrics of the resected proximal tibial surface. ResultsThe dimensions of the tibial plateau of Indian knees demonstrated significant differences according to gender (P<0.05) in terms of size. The shape parameters are not different significantly. When compared to all other ethnicities the Indian knee differs in size as well as the shape parameters i.e. Aspect ratio. ConclusionClinically relevant differences in proximal tibia morphology at the level of proximal TKA resections across ethnicities can lead to mismatch of sizes of Western TKA implants in Indian patients. Tibial component designs should be done by considering the morphometry of knee in Indian population. Indian females were found to have significant smaller dimension of tibia in terms of size than. But the impact of small sample size and single centre on study warrant a multicentric study with large sample size.

Computer tomography 3D reconstruction based study of knee anthropometry of Indian population: Comparison with other ethnic groups and current TKA implants

Introduction: Most of the implants used for total knee arthroplasty in Asian patients have been produced based on anthropometry of Western people. Anthropometric studies have shown that there are significant variations in knee morphology between the Asian and Western population. Data of Indian knee morphometry of healthy and non osteoarthritic knee was lacking. Objective of this study was to study the knee anthropometry of Indian population and its comparison with other ethnic groups and current TKA Implants. Materials and Methods: 60 patients, 29 female and 31 male with peri-articlar knee injuries from the period of June 2016 to November 2016 were studied. 3D reconstruction of normal knee of the patients undergoing CT scan for injured knee was done. Measurement of the mediolateral width, anteroposterior width and aspect ratio of distal femur and proximal tibia was done. Data was compared with other ethnic groups and currently available and commonly used knee systems. Results: Indian females were found to have significantly (p>0.01) smaller dimensions of femur and tibia than Indian males and both had smaller aspect ratios than the Western population. Also study suggests that there is a morphological mismatch between commonly used implants and Indian knees. Conclusion: Our study suggests that why Western implant mismatches when implanted in Indian patients. Also this study provides definite rationale for designing total knee prosthesis, especially a gender-specific design suitable for the Indian population.

Quantification of Indian femur: Dry bone anthropometry in relation to total knee arthroplasty

To study the distal femoral anatomy in Indian population via dry femoral bone measurements and to quantify its effect with relation to total knee arthroplasty. Accurate positioning and sizing of femoral components are important for stability and better outcome.Anatomic measurements on 70 adult cadaveric distal femora were performed using a standardized vernier caliper. The femurs were also photographed in both sagittal and coronal view for bowing and length measurements.The mean length was 42.85cm (±2.82). 39 femurs belonged to the right side. There were 45 males and 25 female femurs. The mean sagittal bowing was measured by radius of curvature and found to have a mean of 109.34cm (±25.00). Coronal bow was mostly lateral and with a mean of 4.12° (±2.78). A total of 13 patients had a medial bow with a mean bowing of 1.73° (±1.32). The mean medial AP was 57.67mm (±3.94). Mean lateral AP was 58.42mm (±3.73).Asian knees are generally considered smaller than their western counterparts. Femoral medio-lateral diameter (fML) was comparatively lesser than other ethnicities published in literature (Chinese and Caucasian). No gender based significant difference was found between aspect ratio. Strong positive correlation between the length of femur and fML (p<0.001) and antero-posterior (fAP) diameter (p<0.001) in both sexes underline the requirement of larger sized implants in larger individual. The average aspect ratio is also less than the western knees. Moreover, a negative correlation (p<0.05) between increasing AR and fAP diameter was noted. This has a crucial bearing on the fitting of the implant, permitting or mitigating the over- or under-hang of the implant.The strength of this study is its basis on healthy non-arthritic distal femur data. The analysis provides a morphometric template for a larger study for designing of gender specific Indian knees suited implant.

Reference axes for optimal femoral rotational alignment in varus osteoarthritic Indian knees - A CT based study.

Optimal rotational alignment of femoral component is important for longevity and success of total knee replacement. Whiteside line (WL), posterior condylar axis (PCA) and femoral transepicondylar axis are various intra-operative landmarks to guide femoral rotation. Each of these has its pros and cons. The aims of our study were to assess the relationship of posterior condylar axis and the antero-posterior axis of femur with the surgical epicondylar axis and evaluate whether degree of deformity or severity of osteoarthritis alters the rotational alignment of the femur when posterior condylar axis is taken as a reference. Are we justified in using a 3° external rotation with respect to posterior condylar axis in each knee? The study is a single-centre, CT-based, cross-sectional, radiological study in 56 bilateral osteoarthritic varus Indian knees. The following were deduced using a uniform standardised method: Whiteside-surgical transepicondylar angle and posterior condylar angle. The study population was subdivided based on age, sex, deformity and grade of osteoarthritis. The mean posterior condylar angle (N=112) was 3.25±1.379° (95% CI). The posterior condylar angle ranged from '0' degrees to '6' degrees with only 27.7% having an angle of 3°. The mean Whiteside-transepicondylar angle (N=112) is 89.72±3.537° (95% CI). PCA and the WL are comparable in establishing the rotational alignment of the femoral component with respect to the surgical transepicondylar axis. A fixed, 3° external rotation with respect to the PCA is an oversimplification and rotational alignment of the knees should be individualised.

Patellar instability in Indian population: relevance of tibial tuberosity and trochlear groove distance.

Introduction: The tibial tuberosity to trochlear groove (TTTG) distance in the western population is extensively studied through various modalities such as X-rays, computerised tomography and magnetic resonance imaging. However, to our knowledge there is very little or no literature support to indicate that TTTG distance has been studied in the Indian population. Methods: We therefore undertook a study to measure the TTTG distance in 100 MRI scans of normal Indian knees. Patients with the following co-morbidities were excluded from the study; ligamentous laxity, patellofemoral instability, mal-alignment and osteoarthritis. We measured TTTG distance on the axial MRI slices using OsiriX software. Results: The mean value for females was found to be 14.07 mm and that for male was found to be 13.34 mm. Our study indicates that the TTTG distance, using MRI scans as measurement modality, in the Indian population is significantly different when compared to the published western data. Discussion: We believe that this study can form the basis for future studies on the relationship between TTTG distance and patellar instability in Indian population.

Distal femoral rotational alignment in the Indian population - An important consideration in total knee arthroplasty.

To measure the angular relationships of distal femoral rotational axes in the normal Indian population. Magnetic Resonance Imaging (MRI) scans of the knee of 40 Indian subjects were used to define the posterior condylar axis, the transepicondylar axis and the Whiteside's line (anteroposterior axis). The posterior condylar angle (PCA) - the angle between the posterior condylar axis and the transepicondylar axis, and the Whiteside-epicondylar angle (W-EP angle) were then calculated. The mean posterior condylar angle in the Indian knee was 4.67° and the mean Whiteside-epicondylar angle was 92.7°. There are differences in the distal femoral rotational axes among various races. The mean PCA and the W-EP angle are more externally rotated in the Indian than in the Western, population, but similar to the Chinese. Using fixed values to define the angular relationships between the axes could lead to malrotation of the femoral component. An understanding of the racial differences is essential while designing implants for the Indian population.