Advantages of cone beam computed tomography for evaluation of subchondral insufficiency fractures of the knee compared to MRI.

To determine the diagnostic yield of cone beam computed tomography (CBCT) compared with 3 T magnetic resonance imaging (MRI) for the evaluation of subchondral insufficiency fractures of the knee. Consecutive patients with subchondral insufficiency fractures of the knee examined by 3 T MRI and CBCT of the femoral condyles were reviewed. Two experienced raters graded the lesion severity on 3 T MRI and CBCT images: grade 1: no signs of a subchondral bone lesion; grade 2: subchondral trabecular fracture or cystic changes, but without infraction of the subchondral bone plate; grade 3: collapse of the subchondral bone plate. Ratings were repeated after six weeks to determine reliability. In addition, the bone lesion size was measured as elliptical area (mm2) and compared between CBCT and T1-weighted MRI sequences. Among 30 patients included (43.3% women; mean age: 60.9 ± 12.8 years; body mass index (BMI) 29.0 ± 12.8 kg/m2), the medial femoral condyle was affected in 21/30 patients (70%). The grading of subchondral lesions between MRI and CBCT did not match in 12 cases (40%). Based on MRI images, an underestimation (i.e., undergrading) compared with CBCT was observed in nine cases (30%), whereas overgrading occurred in three cases (10%). Compared to CBCT, routine T1-weighted 3 T sequences significantly overestimated osseus defect zones in sagittal (84.7 ± 68.9 mm2 vs. 35.9 ± 38.2 mm2, p < 0.01, Cohen's d = 1.14) and coronal orientation (53.1 ± 24.0 mm2 vs. 22.0 ± 15.2 mm2, p < 0.01, Cohen's d = 1.23). The reproducibility of the grading determined by intra- and inter-rater agreement was very high in MRI (intra-class correlation coefficient (ICC) 0.78 and 0.90, respectively) and CBCT (ICC 0.96 and 0.96, respectively). In patients with subchondral insufficiency fractures of the knee, the use of CBCT revealed discrepancies in lesion grading compared with MRI. These findings are clinically relevant, as precise determination of subchondral bone plate integrity may influence the decision about conservative or surgical treatment. CBCT represents our imaging modality of choice for grading the lesion and assessing subchondral bone plate integrity. MRI remains the gold standard modality to detect especially early stages.

A slight degree of osteoarthritis appears to be present after anterior cruciate ligament reconstruction compared with contralateral healthy knees at a minimum of 20 years: A systematic review of the literature.

Purpose: The aim of the present systematic review was to quantitatively synthesize the best literature evidence regarding osteoarthritis developing after anterior cruciate ligament reconstruction (ACLR), including only studies with a follow-up duration of at least 20 years. Material and Methods: A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines on four electronic databases (PubMed, Scopus, EMBASE and Cochrane Library). The outcome measures extracted from the studies were failure rate, subsequent knee surgery on the same knee, radiographic development of osteoarthritis measured with Kellgren-Lawrence, International Knee Documentation Committee (IKDC) radiographic score and Ahlbäck classification. The health of both the ACLR knee and the contralateral knee was compared. Results: A total of 1552 patients were included in the study, of which 1290 (83.11%) were operated on using a patellar tendon graft, 190 (12.24%) with hamstrings, 27 (1.73%) with an iliotibial band and 45 (2.89%) with patellar tendon plus a ligament augmentation device (LAD). The mean age at the time of surgery was 25.18 ± 1.91 years, and the mean follow-up time was 23.34 ± 2.56 years. Analysing IDKC Score at final follow-up, ACLR Group showed a higher degree of OA compared with contralateral healthy knee (p < 0.01), but only 33.2% (324/976) of the patients showed a moderate to severe degree (Grade C or D) of osteoarthritis, while for Kellgren-Lawrence, ACLR Group showed a higher degree of OA compared with contralateral healthy knee (p < 0.01), but only 28.9% (196/678) of the patients showed a moderate to severe degree (Grade III or IV) of osteoarthritis. In total, 1552 patients were registered, 155 reruptures (9.98%) and a total of 300 (19.3%) new surgeries, of which 228 meniscectomy (14.69%), 21 (1.35%) knee arthroplasty and 17 (1.09%) hardware removal were recorded. Conclusions: ACL reconstruction appears to result in mild osteoarthritis in the long term in most of the patients and only less than 33.2% develop a moderate to severe degree of knee OA according to IKDC radiographic score. A slight degree of osteoarthritis appears to be present in ACLR knees compared with contralateral healthy knees. Level of Evidence: Level IV.

The joint line convergence angle (JLCA) correlates with intra-articular arthritis.

PURPOSE: Knees with unicompartmental varus osteoarthritis (OA) usually display a combination of tibiofemoral bony deformity and increased joint line convergence angle (JLCA). The JLCA is a product of intra-articular deformity and lateral soft tissue laxity. This study aims to define the correlation between the JLCA and progression of OA. METHODS: A retrospective radiological analysis of 501 patients, who underwent either high tibial osteotomy (HTO) or unicompartmental knee arthroplasty (UKA), was performed. The preoperative OA grade was reported based on the Ahlbäck and the Kellgren-Lawrence (KL). The hip-knee-ankle angle (HKA), the medial proximal tibial angle (MPTA), the mechanical lateral distal femoral angle (mLDFA) and the joint line convergence angle (JLCA) were recorded. The primary outcome was the relationship between the JLCA values and the OA grade. The secondary outcomes were comparing the JLCA and other alignment parameter values between HTO and UKA groups. RESULTS: A total of 501 (59.3% females n = 297) cases were included, comprising 293 cases of HTO and 208 cases of UKA. Patients had a mean age of 57.63 ± 8.97 years, a mean BMI of 28.37 ± 7.39 kg/m2. Patients with Ahlbäck grade 2 represented 49.3% of all patients (n = 247) and patients with KL grade 3 represented 54.7% of all patients (n = 274). A high JLCA was observed in both groups. The reported mean JLCA in the UKA group was 3.69 ± 2.1°, and in the HTO group was 2.93 ± 1.82. There was a significant association between the increase in the JLCA and the progression of OA based on both the Ahlbäck and KL grades (both p values < 0.001). The mean JLCA in patients with Ahlbäck grades 1 and 4 was 1.48 ± 1.32°, and 7 ± 0.93°, respectively. The mean JLCA in patients with KL grades 1 and 4 was 1.77 ± 1.42°, and 4.89 ± 1.73°, respectively. The mean recorded preoperative HKA angle in the UKA group was 175.06 ± 3.08°, and in the HTO group was 173.26 ± 3.02°, whereas the mean MPTA was 88.63 ± 1.72° for the UKA group and 89.31 ± 2.29° for the HTO group. CONCLUSION: The JLCA progressively increases with osteoarthritis progression in patients with unicompartmental varus knee osteoarthritis. The JLCA can potentially be used as a grading parameter for osteoarthritis progression akin to Ahlbäck and Kellgren-Lawrence grading systems.

Preoperative Ahlbäck radiographic classification grade significantly influences clinical outcomes of double level osteotomy for osteoarthritic knees with severe varus deformity.

PURPOSE: The purpose of this study was to examine the relationship between preoperative Ahlbäck radiographic classification grade and the clinical outcomes of double level osteotomy (DLO) performed for osteoarthritic knees with severe varus deformity. METHODS: The study population comprised a consecutive series of 99 knees (68 patients) for which DLO was performed and follow-up results for a minimum of two years were available. The Ahlbäck radiographic classification system was used to determine the osteoarthritic grade. The following radiological parameters for alignment and bone geometry were measured: mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), joint-line convergence angle (JLCA), and mechanical tibiofemoral angle (mTFA). Clinical results were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) subjective score preoperatively and at 2 years after surgery. Difference between preoperative and postoperative measurements as well as relationship between Ahlbäck grade and radiological/clinical results were statistically assessed. RESULTS: The average age of the study participants was 60.9 ± 6.2 years and the mean follow-up period was 45.4 ± 15.2 months. Each of the radiological parameters exhibited preoperative abnormal values. Knees with Ahlbäck grade 3 and 4 osteoarthritis exhibited significantly greater JLCA and mTFA than grade 1 knees. Two years post-surgery, all radiological parameter values measured within a normal range. Clinical evaluation showed significant improvement in KOOS after surgery. Analysis of the relationship between Ahlbäck grade and clinical score showed that the 2-year postoperative KOOS scores in grade 3 and 4 osteoarthritic knees were significantly lower than grade 1 knees (with the mean 2-year KOOS scores of 350.0 ± 79.9, 317.9 ± 78.3, and 420.2 ± 42.9, respectively). CONCLUSIONS: While DLO may produce significant radiological and clinical improvement in knees with joint space obliteration, Ahlbäck grade 3 and 4 osteoarthritic knees associated with larger JLCA and mTFA showed less satisfactory clinical results compared to grade 1 knees. LEVEL OF EVIDENCE: IV case series.

Do Ahlbäck scores identify subgroups with different magnitudes of cartilage thickness loss in patients with moderate to severe radiographic osteoarthritis? One-year follow-up data from the Osteoarthritis Initiative.

OBJECTIVE: Kellgren-Lawrence grades (KLG) are frequently used for patient selection in clinical trials. The Ahlbäck radiographic grading system has been developed for moderate and severe knee OA. KLG 3 is comparable to Ahlbäck 1 and KLG 4 is subdivided into Ahlbäck 2-5. The objective of this study was to investigate if the Ahlbäck scoring system is able to subdivide patients with moderate to severe knee OA (KLG 3/4) into groups with different sensitivity to change in cartilage thickness. MATERIALS AND METHODS: This study was based on 108 Osteoarthritis Initiative (OAI) participants with KLG 3/4. Baseline KLG scores were available from the OAI database; Ahlbäck scores were performed using the same x-rays. Cartilage thickness change in the weight-bearing femorotibial cartilage was analysed from baseline and year 1 3D FLASH MRI for the entire femorotibial joint (FTJ), the medial (MFTC) and the lateral compartment (LFTC) and for the location-independent ordered values 1 and 16 (OV 1/OV 16) representing the subregions with largest loss (OV 1) and gain (OV 16) within each knee. RESULTS: Of the 108 patients, n = 30/78 had KLG 3/4. The corresponding Ahlbäck scores (1-5) were n = 30/33/36/9/10. Cartilage thickness changes between Ahlbäck groups showed no statistically significant difference for FTJ, MFTC, LFTC and OV 1, but change in OV 16 was significantly higher in Ahlbäck 4 knees (p = 0.03) compared to Ahlbäck 1-3 knees. CONCLUSION: Radiographic knee OA grading with Ahlbäck scores was not superior to KLG for prediction of cartilage thickness loss over 1 year, in patients with moderate and severe knee OA supporting the continuous use of the easier and more widely used KLG.

Radiographic severity, extent and pattern of cartilage loss are not associated with patient reported outcomes before or after total knee arthroplasty in end-stage knee osteoarthritis.

BACKGROUND: The aim of this study was to determine if radiographic severity, extent or pattern of knee osteoarthritis was associated with pain and function before total knee arthroplasty (TKA) or improvement therein one year after TKA. METHODS: A prospective study of 259 patients undergoing unilateral TKA for Kellgren-Lawrence (KL) grade ≥ 3 knee osteoarthritis was conducted: mean age 69.8 ± 9.7 (44-91); mean BMI 31.0 ± 5.8 (17-52); 152/259 (58.7%) female. Preoperative radiographs were assessed using the KL and Ahlback systems. Preoperatively and 1 year postoperatively patients completed Oxford Knee Scores, VAS-Pain and EQ-5D scores. Full thickness cartilage loss was recorded intraoperatively. RESULTS: Median radiographic severity was Ahlback 2, KL 4: 51/259 (19.7%) hypertrophic; 23/259 (8.8%) atrophic. Neither Ahlback nor Kellgren-Lawrence OA grade was associated with OKS, VAS Pain or EQ-5D prior to TKA (p > 0.05). The extent and pattern of cartilage loss did not affect preoperative PROMs. Radiographic OA severity, compartment involvement, and pattern of cartilage loss were not significantly associated with PROMs or improvements therein following TKA (p > 0.05). Hypertrophic OA was associated with less pain before TKA (difference 6.8, 0.23-13.9 95%CI, p = 0.044), and worse improvement in OKS following TKA (difference -3.41, -6.8 to -0.05 95%CI, p = 0.047). Better preoperative OKS and hypertrophic OA were independently associated with poorer improvement in OKS 1 year following TKA (R2 = 0.208). CONCLUSION: Provided at least one compartment has KL grade ≥ 3 changes, further radiographic severity, pattern or extent of cartilage loss did not affect PROMs before or after TKA: multicompartmental was no worse than unicompartmental disease.

Reliability of three radiographic classification systems for knee osteoarthritis among observers of different experience levels.

OBJECTIVE: To assess the intra- and inter-observer reliability of three commonly referenced radiographic classification systems for knee osteoarthritis in a cohort of arthroplasty candidates. MATERIALS AND METHODS: Pre-operative radiographs of 112 patients who subsequently underwent primary total knee arthroplasty were evaluated by four independent observers of varying experience. Each x-ray was de-identified, randomised, and classified according to the International Knee Documentation Committee, Kellgren-Lawrence, and Ahlbäck classifications. After a 2-week interval period, each x-ray was again randomised and re-classified. RESULTS: Regarding inter-observer reliability, the Ahlbäck and Kellgren-Lawrence classifications were shown to have 'substantial agreement' (AC 0.79 and 0.85 respectively), and the IKDC was shown to have 'almost perfect agreement' (AC 0.97). Regarding intra-observer reliability, the two more experienced observers demonstrated 'good' or 'excellent' reliability for all classification systems, and the two less experienced observers demonstrated 'moderate' intra-observer reliability for all classification systems. CONCLUSION: The International Knee Documentation Committee, Kellgren-Lawrence, and Ahlbäck radiographic classifications demonstrated adequate intra- and inter-observer reliability, supporting their potential implementation in surgical practice, or in epidemiological and clinical studies of knee osteoarthritis in a comparable cohort of patients. Clinical experience was positively correlated with intra-observer reliability. Whilst the International Knee Documentation Committee classification demonstrated the greatest reliability, this is likely due to its conservative definitions, and the Ahlbäck and Kellgren-Lawrence classifications are likely more reflective of the spectrum of disease severity encountered in an older patient cohort.

Histopathological analysis of the posterior cruciate ligament in primary osteoarthritis.

BACKGROUND: According to some authors, the indication of an arthroplasty maintaining the posterior cruciate ligament (PCL) demands adequate structural preservation and proprioceptive function of this ligament. The nervous fibers contained in the synovial neurovascular bundle (NVB) around the PCL are involved in proprioception. A study evaluating the grade of PCL and NVB degeneration by using clinical, radiological, and perioperative parameters in knee arthritis patients, in theory, could help surgeons in the decision of preserving or not preserving the PCL in a particular patient. QUESTIONS: (1) Can the degree of the PCL collagen fibers degeneration be predicted by clinical, radiographic, and perioperative parameters in knee arthritis patients? (2) Is the NVB histological degeneration status predictable using clinical, radiographic, and perioperative parameters in the same subset of patients? (3) Is there a correlation between the degree of the PCL collagen fibers degeneration and NVB status in knee arthritis patients? METHODS: Eighty-nine PCLs (85 patients) obtained from total knee replacement surgery were studied. The histologic degeneration of PCL collagen fibers and the NVB status (preserved, degenerated, not detected) were evaluated. These histological degeneration patterns were correlated with clinical and radiographic parameters and with anterior cruciate ligament (ACL) status. RESULTS: A small prevalence of preserved NVB was related to Grades IV and V of Ahlbäck's classification, ACL absence, and severe PCL degeneration. The clinical and radiological parameters studied were not able to predict the grade of histological degeneration of the PCL. CONCLUSIONS: Ahlbäck's classification and ACL status provided useful information about NVB integrity. LEVEL OF EVIDENCE: Basic Science Level IV.

Arthroscopic assisted percutaneous bone grafting and screw fixation for the treatment of lateral tibial plateau fractures：A 4-year follow-up / 中国组织工程研究

10.3969/j.issn.2095-4344.2013.26.009