Nonarthritic Knees Research Articles

Immunoglobulin G complexes without sialic acids enhance osteoclastogenesis but do not affect arthritis-mediated bone loss.

Immunoglobulin G (IgG) is important in clearance and recognition of previously presented antigens and after activation, IgGs can interact with the Fc gamma receptors (FcγRs) on haematopoietic cells, including bone‐resorbing osteoclasts. The pathogenicity of IgG, that is the ability to elicit stimulatory effects via FcγRs, can be modulated by attachment of sugar moieties, including sialic acids. Human IgGs and autoantibodies are associated with bone loss in autoimmune disease. However, the impact of polyclonal murine IgG via FcγRs on bone loss is poorly understood. Here, we investigate if heat‐aggregated activated murine polyclonal IgG complexes have any direct effects on murine osteoclasts and if they modulate arthritis‐mediated bone loss. Using cell cultures of murine osteoclasts, we show that IgG complexes without sialic acids (de‐IgG complexes) enhance receptor activator of nuclear factor kappa‐Β ligand (RANKL)‐stimulated osteoclastogenesis, an effect associated with increased FcγRIII expression. Using an in vivo model of arthritis‐mediated bone loss, where IgG complexes were injected into arthritic knees, no effect on the severity of arthritis or the degree of arthritis‐mediated bone loss was detected. Interestingly, injection of de‐IgG complexes into non‐arthritic knees increased osteoclast formation and enhanced bone erosions. Our findings show that activated de‐IgG complexes have no additive effect on arthritis‐mediated bone loss. However, de‐IgG complexes potentiate murine osteoclastogenesis and enhance local bone erosion in non‐arthritic bones, further confirming the link between the adaptive immune system and bone.

Primary osteoarthritic knees have more varus coronal alignment of the femur compared to young non-arthritic knees in a large cohort study.

Many surgeons are performing total knee arthroplasty (TKA) with an aim to reproducing native anatomical coronal alignment. Yet, it remains unclear if primary osteoarthritic and non-osteoarthritic populations have similar knee coronal alignment. This study aims to describe and compare the distribution of femoral and tibial coronal alignment in a large primary osteoarthritic cohort and a young non-osteoarthritic cohort. This is a retrospective analysis of a monocentric prospectively gathered data, from 1990 to 2019, of 2859 consecutive primary osteoarthritic knees in 2279 patients. Patients underwent standardized long-leg radiographs. Femoral mechanical angle (FMA) and tibial mechanical angle (TMA) were digitally measured using software. Femoral, tibial and knee phenotypes were analyzed, and descriptive data were reported. Data were compared to a young non-osteoarthritic population previously described. In osteoarthritic knees, the mean FMA was 91° ± 2.9° (range 86°-100°) and the mean TMA was 87° ± 3.1° (range 80°-94°). No significant difference was observed for FMA and TMA between genders. The most common femoral and tibial phenotypes were varus (38.7%) and neutral (37.1%). The most frequent knee phenotype was a varus femoral phenotype with a neutral tibial phenotype (15.5%), which is different to the non-osteoarthritic population. This study showed the wide distribution of knee phenotypes in a large osteoarthritic cohort. There was more varus distribution of the femoral coronal alignment compared to a non-osteoarthritic population, suggesting consideration and potential adaptation of the realignment strategy of the femoral component during TKA. III.

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.

Partial Meniscectomy for Degenerative Medial Meniscal Root Tears Shows Favorable Outcomes in Well-Aligned, Nonarthritic Knees

Background: Arthroscopic meniscectomy has been commonly performed for persistent pain caused by degenerative medial meniscal posterior root tears (MMPRTs). However, risk factors that affect long-term outcomes and joint survivorship after meniscectomy are unclear. Purpose: To identify the risk factors associated with end-stage osteoarthritis after arthroscopic meniscectomy for degenerative MMPRT for middle-aged or elderly patients and to determine the joint survivorship according to the identified risk factors. Study Design: Case-control study; Level of evidence, 3. Methods: Data from 288 patients (24 male and 264 female), followed for at least 5 years after arthroscopic meniscectomy for degenerative MMPRTs performed between 1999 and 2010, were examined retrospectively. The modified Lysholm score was used for clinical evaluation. Cox proportional hazards regression analysis was used to assess factors that affect joint survivorship when conversion to total knee arthroplasty (TKA) was taken as the endpoint; these factors were age, sex, body mass index (BMI), preoperative tibiofemoral alignment (varus [<2° valgus] vs well-aligned [2°-10° valgus]), preoperative Kellgren-Lawrence grade (0 or 1 vs 2 or 3), and the modified Outerbridge grade of the medial compartment. Kaplan-Meier survival analysis and the log-rank test were used to compare overall survivorship with respect to each significant risk factor. Results: Mean age at the time of surgery was 58.9 years (range, 43-78 years). Sixty (20.8%) patients underwent TKA at 7.0 ± 3.6 years (range, 1.1-14.4 years) postoperatively. The mean follow-up time for those who did not undergo TKA was 8.9 ± 2.9 years (range, 4.5-16.5 years). The overall modified Lysholm score improved from 64.4 to 81.3 (P < .001), but progression of radiographic arthritis was noted in 156 (61.9%) patients (P < .001) at 2 years postoperatively. Age (hazard ratio [HR] = 1.049), BMI (HR = 1.092), varus alignment (HR = 2.283), and Kellgren-Lawrence grade 2 or higher (HR = 2.960) were significant risk factors for end-stage arthritis requiring TKA. Well-aligned nonarthritic knees (n = 131, 45.5%) survived significantly longer before requiring TKA than did knees with varus alignment or radiographic arthritis (P < .05). The 5- and 10-year survival rates in these low-risk groups were 97.7% (95% CI, 95.2%-100.2%) and 89.1% (95% CI, 82.4%-95.8%), respectively. Conclusion: Arthroscopic meniscectomy is an effective treatment for degenerative MMPRTs, with favorable long-term survival in well-aligned nonarthritic knees. However, meniscectomy should be undertaken cautiously in patients with varus alignment and preoperative radiographic osteoarthritis.

Full-Thickness Cartilage Defects Are Important Independent Predictive Factors for Progression to Total Knee Arthroplasty in Older Adults with Minimal to Moderate Osteoarthritis: Data from the Osteoarthritis Initiative.

Knee osteoarthritis (OA) severity on radiographs is not a reliable predictor of symptom severity. The purpose of this study was to determine whether full-thickness defects or OA grade are predictive of the progression to total knee arthroplasty in older patients without end-stage arthritis. This study included 1,319 adults aged 45 to 79 years (mean age [and standard deviation], 61.0 ± 9.2 years) who were enrolled in the Osteoarthritis Initiative, a prospective multicenter study with median 9-year follow-up data. All participants had Kellgren-Lawrence grade-0 to 3 (no to moderate) OA on bilateral radiographs; patients with grade-4 (severe) OA were excluded. The presence and total surface area of full-thickness cartilage defects on the tibia or the weight-bearing portion of the femoral condyle were determined. The risk of total knee arthroplasty due to defect presence and size as well as OA grade was determined with Cox proportional-hazards modeling after controlling for baseline variables including, but not limited to, age, sex, race, weight, knee alignment, symptom severity, quality-of-life scores, and activity level. Four hundred and ninety-six patients (37.6%) had full-thickness defects. The incidence of knee arthroplasty was 0.57% per person-year for adults without a full-thickness defect and 2.15% for those with a defect. After adjusting for confounders, the presence of a full-thickness defect increased the risk of total knee arthroplasty regardless of OA grade, with higher risk demonstrated for larger (≥2 cm) defects (hazard ratio [HR] = 5.27 [95% confidence interval (CI) = 2.70 to 10.3]; p < 0.001) compared with smaller (<2 cm) defects (HR = 2.65 [95% CI = 1.60 to 4.37]; p < 0.001). Compared with nonarthritic knees (grade 0 to 1), mild arthritis (grade 2) did not increase total knee arthroplasty risk (HR = 0.71 [95% CI = 0.31 to 1.60]); moderate arthritis (grade 3) increased total knee arthroplasty risk in adults without a full-thickness defect (HR = 3.15 [95% CI = 1.34 to 7.40]; p = 0.009) but not in adults with a defect (HR = 0.64 [95% CI = 0.28 to 1.49]; p = 0.30). Full-thickness cartilage defects were a major determinant of future knee arthroplasty in older adults with minimal to moderate OA, even after adjusting for baseline knee symptom severity. Baseline radiographic severity grade was only associated with future total knee arthroplasty risk in the absence of a full-thickness defect. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Medially-stabilized total knee arthroplasty does not alter knee laxity and balance in cadaveric knees.

Instability after total knee arthroplasty (TKA) can lead to suboptimal outcomes and revision surgery. Medially-stabilized implants aim to more closely replicate normal knee motion than other implants following TKA, but no study has investigated knee laxity (motion under applied loads) and balance (i.e., difference in varus/valgus motion under load) following medially-stabilized TKA. The primary purposes of this study were to investigate how medially-stabilized implants change knee laxity in non-arthritic, cadaveric knees, and if it produces a balanced knee after TKA. Force-displacement data were collected on 18 non-arthritic cadaveric knees before and after arthroplasty using medially-stabilized implants. Varus-valgus and anterior-posterior laxity and varus-valgus balance were compared between native and medially-stabilized knees at 0°, 20°, 60°, and 90° under three different loading conditions. Varus-valgus and anterior-posterior laxities were not different between native and medially-stabilized knees under most testing conditions (p ≥ 0.068), but differences of approximately 2° less varus-valgus laxity at 20° of flexion and 4 mm more anterior-posterior laxity at 90° were present from native laxities (p < 0.017) Medially-stabilized implant balance had ≤1.5° varus bias at all flexion angles. Future studies should confirm if the consistent laxity afforded by the medially-stabilized implant is associated with better and more predictable postoperative outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:335-349, 2019.

Does medial-to-lateral femoral posterior condylar offset difference effect accuracy of established reference axes for determining femoral component rotation in total knee arthroplasty?

Aims and Objectives: The femoral posterior condylar offset (PCO) has been viewed with increased significance for knee joint movement patterns and has been discussed for its possible implication for femoral component rotation in total knee arthroplasty (TKA). However, a great inter-individual variability in medial and lateral PCO size has also been demonstrated. Though the medial and lateral PCO seem closely related to the functional flexion axis (fFA), determined by the radius curvature of the medial and lateral femoral condyle, the relationship of both parameters considering their impact on the accuracy of established reference axes for determining femoral component rotation in TKA remains unknown. The objective of this paper was, therefore, to compare the individual fFA with the anatomical and surgical transepicondylar axis (aTEA; sTEA) and with the posterior condylar axis (PCA) considering the medial and lateral PCO size. It was hypothesized that the disparity of the PCO influences the accuracy of the sTEA, aTEA, and PCA for determination of femoral component rotation in TKA. Materials and Methods: MRI investigations of 56 consecutive non-arthritic knee joints (male/female 28/28; mean age 22.8 years; range 16-59 years) were used for this study. Coronal, sagittal and transverse MRI images were used to measure the medial and lateral PCO and to determine the fFA, aTEA, sTEA, and PCA for each subject as described previously. A paired two-tailed t-test was used to test for differences between the medial and lateral PCO sizes. Deviation of the aTEA, sTEA and PCA from the fFA were analyzed with a one-sample t-test. Correlation analysis (Pearson r) was used to determine the relationship between the PCO ratio (medial-to-lateral PCO) and the deviation of the aTEA, sTEA and PCA from the fFA in each subject. The level of significance was set at 0.05. Results: The mean medial PCO was 34.0 mm (90%CI 28.72-30.55 mm; range 26.3 to 44.7 mm) and the lateral PCO averaged 29.64 mm (90%CI 30.3-31.4 mm; range 14.3 to 39.1 mm) (p<0.0001). The medial-to-lateral PCO ratio was 1.16 (90%CI 1.13 -1.19; range 0.93 to 1.85). The aTEA showed an increased external rotation in relation to the fFA throughout the whole PCO ratio range (mean deviation 4.2°; 95%CI 3.8°-4.6°; range -4.2° to 10.1°; p<0.0001), whereas the sTEA tends towards a slight but significant internal rotation throughout the PCO ratio range (mean deviation -1.6°; 95%CI -2.1°- -1.2°; range -8.1° to 4.8°; p<0.0001). The PCA showed the best conformity with the fFA (mean difference -0.2°; 95%CI -0.5°-0.2°; range -6° to 5.3°; p=0.36) and was most robust against medial-to-lateral PCO variations. A weak but significant positive correlation between the PCO ratio and the deviation from the fFA was solely found for the sTEA (r=0.28; p=0.042). Conclusion: Differences of the medial and lateral PCO size are a common finding. The PCA had the best match with the fFA, regardless of medial-to-lateral PCO disparity. Only the sTEA was influenced to a small extent by variation of the PCO-ratio.

Anthropometric Measurements of Knee Joints in the Hispanic Population

BackgroundTotal knee arthroplasty (TKA) systems provide a set of incrementally sized tibial and femoral components intended to accommodate most knee parameters. However, the most commonly used systems in the United States were developed using data from Caucasian patients which might not lead to the best fit in non-Caucasians. Therefore, we wanted to evaluate whether these TKA systems proportionally match femoral and tibial measurements in Hispanics. MethodsAll lower extremity magnetic resonance imaging performed at our institution between January 2007 and October 2015 were screened. A total of 500 nonarthritic knees from the same number of Hispanic patients were included in this retrospective descriptive radiographic study. Intraoperative osseous TKA resections were simulated on magnetic resonance imaging. Linear regression analyses were used to contrast the mediolateral (ML) width/anteroposterior (AP) length of simulated resected femoral condyle and tibia with the ML/AP dimensions of components offered by 4 current TKA systems. ResultsSimulated resected male femurs tended to be wider than most TKA system components for a given AP size, probably leading to component ML underhang. Altogether, systems studied accommodated most AP and ML measurements of female condyles. However, we identified subsets of Hispanic female patients with certain AP lengths and/or ML widths that particular knee systems could not accommodate. Resected male and female tibias tended to be slightly narrower than all TKA systems for a given AP size. ConclusionThe results of our study provide valuable data concerning the unique morphology of the Hispanic knee. These data can assist surgeons in the selection of the most suitable TKA systems for these patients.

Femoral rotational asymmetry is a common anatomical variant.

The sulcus line (SL) is a three-dimensional landmark that corrects for individual variation in the coronal alignment of the trochlear groove in contrast to the traditional Whiteside's line (WL). Femoral rotational asymmetry (FRA) is an anatomical variation in which the posterior condyles and trochlear groove are not perpendicular to each other. This study aims to measure the SL and assess its reliability relative to WL, in addition to measuring and classifying the FRA. A retrospective analysis of a series of 191 CT scans of nonarthritic knees was performed. Measurements were taken of rotational landmarks in three-dimensional reconstructions. The variability and outlier rate of SL was less than WL (P < 0.05), however, it was also greater than the posterior condylar line (PC) (P < 0.05). Averaging the PC + 3° and the SL did not change the rate of femoral malrotation relative to the surgical epicondylar axis (SEA) (P > 0.05), however it decreased the rate of change of the rotational alignment of the trochlear groove between the native knee and the prosthetic knee from 31% to 5% (P < 0.05). FRA was classified and was >5° in 56/191 (29%) of cases. The SL technique is more accurate than WL for determining the rotational alignment of the trochlear groove. Nonarthritic femora have a high rate of rotational asymmetry. Identifying and classifying FRA in individual cases allows the femoral component to be inserted in a position which gives the best possible match to both the native posterior condyles and trochlear groove. Clin. Anat. 31:551-559, 2018. © 2018 Wiley Periodicals, Inc.

The Effects of Meniscal Geometry on Susceptibility for Meniscal and ACL Injury in Non-Arthritic Knees: A Retrospective Case-Control Study.

Prior studies have not found significant differences in meniscal parameters between patients with meniscal and ligamentous injury and those without. The purpose of this study was to determine whether such relationships exist. Clinical records and magnetic resonance images of three subject groups were reviewed. Group 1 solely had meniscal tears (medial/lateral), Group 2 had meniscal tears with concurrent ACL tears, and Group 3 had healthy knees. The mean age of subjects included was 35.9 years (range 8.2-72.6). The height, width, diagonal, slope, and cross-sectional area for the anterior and posterior horns of the lateral and medial menisci were assessed. Normal distribution of data was confirmed by the Shapiro-Wilk test and analysis of variance with a post hoc Tukey's test was used to assess potential differences. p < 0.05 was set as the level of significance. There was no difference between the meniscal slopes of patients with and without meniscal tears (p = 0.77-1.0). Meniscal height (p = 0.0001-0.024) and width (p = 0.0001-0.046) demonstrated significant differences in all horns. Cross-sectional area was larger in the torn group (p = 0.0001-0.012). To compare intact and torn menisci, a logistical regression model was used and found to be significantly different from the constant model (p < 0.0001). Predictive success was 80.5%. A logistical regression model was used comparing undamaged menisci with torn menisci with accompanying anterior cruciate ligament (ACL) tear and was significant (p < 0.0001). A larger cross-sectional meniscal area in both the anterior and posterior horns of both menisci was a risk factor for isolated meniscal tears and combined meniscal and ACL tears. It has been postulated that certain demographic variables, such as gender, age, and body mass index, may be risk factors associated with ACL and meniscal injuries. However, the relationship between intrinsic morphology, namely meniscal size and shape, and risk of injury is unclear. The majority of studies have focused on meniscal morphology/geometry and its association with degenerative tears in patients with end-stage osteoarthritis rather than on acute meniscoligamentous injury. In this study of non-arthritic knees, a larger cross-sectional meniscal area in both the anterior and posterior horns of both menisci was a risk factor for having both an isolated meniscal tear as well as a combined meniscal and ACL tear. With advances in the field of meniscal repair, particularly with allograft procedures, more attention should be paid to meniscal cross-sectional area because it may play a role in the natural history of knee injury.

Distal Femoral Rotation Correlates With Proximal Tibial Joint Line Obliquity: A Consideration for Kinematic Total Knee Arthroplasty

BackgroundWe hypothesized that there is a correlation between the distal femoral rotation and proximal tibial joint line obliquity in nonarthritic knees. This has significance for kinematic knee arthroplasty, in which the target knee alignment desired approximates the knee before disease. MethodsFifty computed tomography scans of nonarthritic knees were evaluated using three-dimensional image processing software. Four distal femoral rotational axes were determined in the axial plane: the transepicondylar axis (TEA), transcondylar axis (TCA), posterior condylar axis (PCA), and a line perpendicular to Whiteside's anterior-posterior axis. Then, angles were measured relative to the TEA. Tibial joint line obliquity was measured as the angle between the proximal tibial plane and a line perpendicular to the axis of the tibia. ResultsThere was a strong positive correlation between PCA-TEA and tibial joint line obliquity (r = 0.68, P < .001) as well as TCA-TEA and tibial joint line obliquity (r = 0.69, P < .001). In addition, the tibial joint line obliquity and TCA-TEA angles were similar, 3.7° ± 2.2° (mean ± standard deviation) and 3.5° ± 1.7°, respectively (mean difference, 0.2° ± 0.2°; P = .369). ConclusionBoth PCA-TEA and TCA-TEA strongly correlated with proximal tibial joint line obliquity indicating a relationship between distal femoral rotational geometry and proximal tibial inclination. These findings could imply that the native knee in flexion attempts to balance the collateral ligaments toward a rectangular flexion space. A higher tibial varus inclination is matched with a more internally rotated distal femur relative to the TEA.

Repeated administration of mazindol reduces spontaneous pain-related behaviors without modifying bone density and microarchitecture in a mouse model of complete Freund's adjuvant-induced knee arthritis.

BackgroundThe role of dopaminergic system in the development of rheumatoid arthritis-related pain, a major symptom in this disease, has not been explored. Therefore, the anti-nociceptive effect of mazindol, a dopamine uptake inhibitor, was evaluated in a model of complete Freund’s adjuvant (CFA)-induced arthritis. Furthermore, as studies have shown that the dopaminergic system regulates bone metabolism, the effect of mazindol on bone mass and microarchitecture was determined.MethodsAdult ICR male mice received intra-articular injections of either CFA or saline into the right knee joint every week. Spontaneous pain-like behaviors (flinching and guarding) and locomotor activity were assessed at day 26 post-first CFA, following which, a single intraperitoneally (i.p.) administered dose of mazindol was given (1, 3 and 10 mg/kg). Then, the antinociceptive effect of a repeated administration of 3 mg/kg mazindol (daily, i.p.; day 15–day 26) was evaluated. Additionally, at day 26, the participation of D1-like, D2-like or opioid receptors in the antinociceptive effect of mazindol was evaluated. The effect of mazindol on bone density and microarchitecture was evaluated by micro-computed tomography.ResultsAcute administration of mazindol decreased the spontaneous pain-like behaviors in a dose-dependent manner without reducing the knee edema. However, mazindol at 10 mg/kg significantly increased the locomotor activity; therefore, 3 mg/kg mazindol was used for further studies. Repeated administration of 3 mg/kg mazindol significantly decreased the pain-like behaviors without modifying locomotor activity. The antinociceptive effect of mazindol was blocked by administration of a D2-like receptor antagonist (haloperidol), but not by administration of D1-like receptor antagonist (SCH 23390) or an opioid receptor antagonist (naloxone). Repeated administration of mazindol did not significantly modify the density and microarchitecture of periarticular bone of the arthritic and nonarthritic knee joints.ConclusionResults suggest that mazindol via D2-like receptors has an antinociceptive role in mice with CFA-induced knee arthritis without modifying the bone health negatively.

Bone morphotypes of the varus and valgus knee.

Coronal deformity correction with total knee arthroplasty (TKA) is an important feature in the treatment of osteoarthritis (OA). The hypothesis of this study was that bone morphology would be different in varus and valgus deformity, both before osteoarthritis development as well as during and after the disease process of OA. Retrospective study with measurements on preoperative and postoperative full leg standing radiographs of 96 patients who underwent TKA. The included patients were selected for this study because they had an OA knee on one side and a non-arthritic knee on the contralateral side presenting the same type of alignment as the to-be-operated knee (varus or valgus alignment on both sides). The control group of 46 subjects was a group of patients with neutral mechanical alignment who presented for ligamentous problems. A single observer measured mechanical alignment, anatomical alignment, anatomical-mechanical femoral angle and intra-articular bone morphology parameters with an accuracy of 1°. Varus OA group has less distal femoral valgus (mLDFA 89°) than control group (87°) and valgus OA group (mLDFA 85°). Varus OA group has same varus obliquity as control group (MPTA 87°) but more than valgus OA group (MPTA 90°). Joint Line Congruency Angle (JLCA) is 3°open on lateral side in varus and medially open in valgus OA group (2°). The non-arthritic valgus group presents a constitutional mechanical valgus of 184° Hip-Knee-Ankle (HKA) angle. Varus deformity in OA as measured with an HKA angle (HKA) <177° is a combination of distal femoral wear, tibial varus obliquity and lateral joint line opening. Valgus deformity in OA with an HKA > 183° is a combination of femoral distal joint line obliquity and wear combined with medial opening due to medial collateral ligament stretching. The clinical importance of bone morphotype analysis is that it shows the intra-articular potential of alignment correction when mechanical axis cuts are performed. Bone morphology in varus and valgus deformity is different before and after osteoarthritis. Perpendicular cuts to mechanical axes do not necessarily lead to neutral mechanical axis. Constitutional mechanical valgus was observed as 184° HKA angle before the development of OA. Level IV study.

Is There Any Benefit in Anterior Cruciate Ligament Reconstruction in Patients Older Than 60 Years?

Background: Results of anterior cruciate ligament (ACL) reconstruction are traditionally excellent in younger and nonarthritic patients. During the past few decades, people older than 60 years have become more active than ever, with more demanding physical lifestyles. An increase also has been noted in active patients with diagnosed ACL injuries. More patients are requesting treatment for ACL deficiency in hopes of returning to preinjury levels of activity. Purpose: The aims of this study were to evaluate the results of ACL reconstruction in patients older than 60 years in terms of functional recovery, return to sports, and postoperative incidence of osteoarthritis and to compare their results with published results of different age groups. Study Design: Case series; Level of evidence, 4. Methods: Consecutive patients older than 60 years with isolated ACL tear and no established osteoarthritic lesions (Ahlbäck grade 1 or no arthritis) who were treated from 2008 to 2013 were retrospectively included in this study. Primary ACL reconstruction was performed with the same technique in all patients by means of single-bundle autologous hamstring tendon graft. Meniscal injuries were treated with partial debridement when required. No further treatment on cartilage lesions was performed. Postoperative rehabilitation was the same in every case. The International Knee Documentation Committee (IKDC) objective grade, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS) were assessed before and after surgery, and the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) score was recorded during the final follow-up. Postoperative incidence of osteoarthritis was evaluated on weightbearing radiographs during final follow-up, and anteroposterior laxity was measured pre- and postoperatively with the use of stress radiographs. Results: Twelve patients with mean age (±SD) of 61.0 ± 1.4 years at the time of surgery were included. They were followed-up for a mean period of 49.6 ± 24.0 months. Eight patients had associated meniscal tears, and 6 patients had International Cartilage Repair Society stage 1 or 2 chondral lesions. Preoperatively, the objective IKDC grades were B in 4 patients, C in 5, and D in 3. After surgery, the IKDC grades were A in 4 patients, B in 7, and grade C in 1. The mean subjective IKDC and Lysholm scores were a respective 43.4 ± 8.4 and 55.7 ± 12.4 preoperatively and 83.8 ± 9.4 and 93.2 ± 9.0 at the final follow-up (P < .05). Ten patients (83%) reported recovery of sports activities, with 6 patients (50%) reaching the same level as before injury. The mean ACL-RSI score was 76.2%. Preoperatively, 50% (n = 6) of patients had Ahlbäck stage 1 medial compartment arthritis, versus 58% (n = 7) at the final follow-up (P = nonsignificant). The side-to-side difference in anterior tibial translation on stress radiographs was 7.2 ± 6.4 mm preoperatively and 1.9 ± 4.3 mm postoperatively (P < .05). No major complications were reported. Conclusion: ACL reconstruction in active patients older than 60 years without arthritis restored knee stability in all treated cases. In these patients, as in younger age groups, ACL reconstruction showed good results on functional recovery while not increasing the risk of midterm functional knee deterioration or evolution of knee arthritis. The majority of patients returned to activities at their preinjury level. These data show that older and active patients with nonarthritic ACL-deficient knees need not be excluded from surgical treatment.

Meniscal allograft subluxations are not associated with preoperative native meniscal subluxations

To determine the relationship between preoperative subluxation of the original menisci and postoperative graft subluxation after lateral meniscal allograft transplantation (MAT). Forty patients who underwent isolated lateral MATs in meniscus-deficient knees with a low-grade chondral lesion (≤ICRS grade 2) were assessed. Lateral subluxation of the native meniscus before meniscectomy and those of remaining meniscal tissue before MAT were measured on mid-coronal MRI scans taken at each time point. Postoperative meniscal subluxation was assessed using MRI at 6months postoperatively, when the full rehabilitation protocols were completed. Correlation analyses were conducted to determine the associations between each of two preoperative lateral displacements and the postoperative graft subluxation. The mean lateral subluxations before primary meniscectomy and before MAT were 0.3±1.0mm and 0.2±0.8mm, respectively. At 6months postoperatively, it was 2.3±1.9mm. There were no significant correlations between the preoperative subluxation at the two preoperative time points and the postoperative extrusion (Spearman rho 2-sided test: ρ=-0.058, (n.s.) for the native meniscus; Pearson r 2-sided test, r=0.309, (n.s.) for the remaining meniscal rim). Between the postoperative nonextruded and extruded groups, there were no significant differences for the preoperative subluxations. There are no associations between preoperative lateral subluxation of the native menisci and postoperative subluxation of meniscal transplants in patients who undergo MAT on the lateral compartment with low-grade arthritic changes. The extrusion phenomenon may be a distinct feature of transplanted menisci rather than an individual characteristic of meniscal displacement. Surgeons need to keep in mind that graft extrusion in nonarthritic knees might occur during transplantation. IV.

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

Rotational alignment of prosthetic components in total knee arthroplasty (TKA) is important to successful outcomes. Component malrotation is a known cause of revision and understanding normal rotational alignment may help recreate normal joint kinematics. To date, no large MRI study assessing femorotibial rotational alignment in nonarthritic knees has been undertaken. Is Insall's tibial axis a reliable rotational landmark against common femoral rotational axes in the nonarthritic patient population? We reviewed 544 knee MRI scans performed for suspected soft tissue pathology and identified Insall's tibial rotational axis as well as the femoral clinical trans-epicondylar axis (TEAc), femoral surgical trans-epicondylar axis (TEAs), posterior condylar articular axis (PCA), and a modified Eckhoff's cylindrical axis. The perpendiculars of these axes were superimposed on Insall's tibial axis, and the angular differences were measured. Insall's axis was internally rotated to the TEAc by 1.4°, externally rotated to Eckhoff's cylindrical axis by 1.8°, externally rotated to the TEAs by 2.7°, and externally rotated to the PCA by 3.5°. The mean deviation from 0° (optimal alignment for each femoral axis) was significantly greater for the PCA relative to all other femoral axis. Insall's axis is a reliable landmark for rotational positioning of the tibial component and may optimize femorotibial kinematics in fixed-bearing TKA.

Evaluation of the size and position of the insertion of the anterior medial meniscus root in varus osteoarthritic knees.

Recent studies have suggested radial displacement of the medial meniscus as a cause of varus knee osteoarthritis (OA). Two anatomical studies reported that such displacement may be associated with anterior insertion of the medial meniscus anterior horn. It was aimed to evaluate the location and area of this insertion in patients with advanced knee OA. Medial meniscus anterior horn insertions were classified into four types, as described in a previously reported classification during 225 total knee arthroplasty (TKA) in 184 patients. The incidence rates of insertion type were compared with previously reported rates in nearly normal or non-arthritic knees. The insertion surface area was also measured during 158 TKAs. Of the 225 knees, 82 (36.4%), 93 (41.3%), 35 (15.6%), and 15 (6.7%) were classified as I, II, III, and IV, respectively. An anteriorly inserted anterior horn was not more frequent in advanced varus OA knees than in previously reported nearly normal or non-arthritic knees. The insertion surface areas were 57.5±18.9, 56.1±16.0, and 56.4±14.4mm2 for types I, II, and III, respectively; these areas did not differ significantly. Since the incidence of an anteriorly inserted medial meniscus anterior horn was not higher in advanced varus OA knees than in normal or non-arthritic knees, an anteriorly inserted anterior horn may have little or no effect on the aetiology of varus OA knees. This study provides some information for clarifying the aetiology of knee OA. IV.

Optical spectroscopic determination of human meniscus composition.

This study investigates the correlation between the composition of human meniscus and its absorption spectrum in the visible (VIS) and near infrared (NIR) spectral range. Meniscus samples (n = 24) were obtained from nonarthritic knees of human cadavers with no history of joint diseases. Specimens (n = 72) were obtained from three distinct sections of the meniscus, namely; anterior, center, posterior. Absorption spectra were acquired from each specimen in the VIS and NIR spectral range (400-1,100 nm). Following spectroscopic probing, the specimens were subjected to biochemical analyses to determine the matrix composition, that is water, hydroxyproline, and uronic acid contents. Multivariate analytical techniques, including principal component analysis (PCA) and partial least squares (PLS) regression, were then used to investigate the correlation between the matrix composition and it spectral response. Our results indicate that the optical absorption of meniscus matrix is related to its composition, and this relationship is optimal in the NIR spectral range (750-1,100 nm). High correlations (R(2) (uronic) = 86.9%, R(2) (water) = 83.8%, R(2) (hydroxyproline) = 81.7%, p < 0.0001) were obtained between the spectral predicted and measured meniscus composition, thus suggesting that spectral data in the NIR range can be utilized for estimating the matrix composition of human meniscus. In conclusion, optical spectroscopy, particularly in the NIR spectral range, is a potential method for evaluating the composition of human meniscus. This presents a promising technique for rapid and nondestructive evaluation of meniscus integrity in real-time during arthroscopic surgery.

Anthropometric difference of the knee on MRI according to gender and age groups.

The purpose of this study was to analyze the anthropometric data from MRI images that were obtained from the non-arthritic knees in Asian adults, and to identify the existence of morphologic differences between age groups. This cross-sectional study included knee MR images of 535 patients (273 males, 262 females) taken for the evaluation of soft-tissue injuries, excluding cases with cartilage defect and malalignment. The age, gender, height, and BMI were also assessed. The patients were grouped into three different 20-year age groups (20-39, 40-59, and 60-79). The MRI analysis was performed on the anthropometric parameters of distal femur and posterior tibial slope. Age-related differences were found in femoral width, distance from the distal and posterior cartilage surface to the medial/lateral epicondyle, medial posterior condylar offset (PCO), and posterior condylar angle (PCA) (all P < 0.001), but not in lateral PCO, and medial/lateral tibial slopes. In the analysis of covariance analyses, significant interaction between gender and age groups was found in most parameters, but not in PCA, distance from the posterior cartilage surface to the medial epicondyle, or medial tibial slope. We found anthropometric differences among age groups exist in most of distal femoral parameters, but not in posterior tibial slope. The results of this study can be used by manufacturers to modify prostheses to be suitable for the future Asian elderly population.

Physiologic characterization of inflammatory arthritis in a rabbit model with BOLD and DCE MRI at 1.5 Tesla.

Our aim was to test the feasibility of blood oxygen level dependent magnetic resonance imaging (BOLD MRI) and dynamic contrast-enhanced (DCE) MRI to monitor periarticular hypoxic/inflammatory changes over time in a juvenile rabbit model of arthritis. We examined arthritic and contralateral nonarthritic knees of 21 juvenile rabbits at baseline and days 1,14, and 28 after induction of arthritis by unilateral intra-articular injection of carrageenin with BOLD and DCE MRI at 1.5 Tesla (T). Nine noninjected rabbits served as controls. Associations between BOLD and DCE-MRI and corresponding intra-articular oxygen pressure (PO2) and blood flow [blood perfusion units (BPU)] (polarographic probes, reference standards) or clinical-histological data were measured by correlation coefficients. Percentage BOLD MRI change obtained in contralateral knees correlated moderately with BPU on day 0 (r = -0.51, p = 0.02) and excellently on day 28 (r = -0.84, p = 0.03). A moderate correlation was observed between peak enhancement DCE MRI (day 1) and BPU measurements in arthritic knees (r = 0.49, p = 0.04). In acute arthritis, BOLD and DCE MRI highly correlated (r = 0.89, p = 0.04; r = 1.0, p < 0.0001) with histological scores in arthritic knees. The proposed techniques are feasible to perform at 1.5 T, and they hold potential as surrogate measures to monitor hypoxic and inflammatory changes over time in arthritis at higher-strength MRI fields. • BOLD and DCE MRI detect interval perisynovial changes in a rabbit knee • BOLD and DCE MRI act as surrogate markers of physiologic changes in arthritis • BOLD MRI signal represents oxygen extraction compared with intra-articular PO 2 • DCE MRI measurements estimate physiologic periarticular vascular properties • In rabbit knees with acute arthritis, BOLD/DCE MRI highly correlated with histological scores.