Time Of Total Knee Replacement Research Articles

Factors Influencing Knee Flexion Range of Movement after Primary Total Knee Arthroplasty : Study of a Consecutive Series over Ten Years

Introduction: Knee flexion after total arthroplasty is not always satisfactory. Our hypothesis: many factors can influence it. Some of these factors have been studied, but with controversial results.
 Methodology: It was a monocentric prospective and comparative study. All primary total knee replacement were included. For each factor, we compared a group of patients with above mean flexion to those with smaller flexion, using comparison of means, regression analysis and the chi square test.
 Results: We had 110 arthroplasties from 88 patients. Three preoperative factors affected the outcome: pre-operative knee flexion < 110°, flexum deformity > 5° and a body mass index above 30kg/m2. The respective Pearson coefficient value for these three factors were +0.50, +0.05, and -0.13.The chi square values were respectively 12.019 (p<0.001) and 6.091 (p<0.02) for the first two ones. Mean postoperative flexion values were significantly low for the patients with high body mass index (p<0.03) and for those with knee flexion < 110° (p<0,001).
 Conclusion: Such studies should be carried out in other settings to prepare later meta-analysis. The effect of early physiotherapy in knee arthritis treatment in preventing knee stiffness at the time of total knee replacement should be evaluated.

Comet assay for quantification of the increased DNA damage burden in primary human chondrocytes with aging and osteoarthritis.

It is known that chondrocytes from joints with osteoarthritis (OA) exhibit high levels of DNA damage, but the degree to which chondrocytes accumulate DNA damage during “normal aging” has not been established. The goal of this study was to quantify the DNA damage present in chondrocytes obtained from cadaveric donors of a wide age range, and to compare the extent of this damage to OA chondrocytes. The alkaline comet assay was used to measure the DNA damage in normal cartilage from the ankle (talus) and the knee (femur) of cadaveric donors, as well as in OA chondrocytes obtained at the time of total knee replacement. Chondrocytes from younger donors (<45 years) had less DNA damage than older donors (>70 years) as assessed by the percentage of DNA in the comet “tail”. In donors between 50 and 60 years old, there was increased DNA damage in chondrocytes from OA cartilage as compared to cadaveric. Talar chondrocytes from 23 donors between the ages of 34 and 78 revealed a linear increase in DNA damage with age (R 2 = 0.865, p < 0.0001). A “two‐tailed” comet assay was used to demonstrate that most of the accumulated damage is in the form of strand breaks as opposed to alkali‐labile base damage. Chondrocytes from young donors required 10 Gy irradiation to recapitulate the DNA damage present in chondrocytes from older donors. Given the potential for DNA damage to contribute to chondrocyte dysfunction and senescence, this study supports the investigation of mechanisms by which hypo‐replicative cell types accumulate high levels of damage.

Incidence of Total Knee Replacement in Patients With Previous Anterior Cruciate Ligament Reconstruction.

To determine the rate of total knee replacement (TKR) after anterior cruciate ligament reconstruction (ACL-R) compared to the general population. Retrospective review. All hospitals that performed TKR and ACL-R in Manitoba between 1980 and 2015. All patients that underwent TKR and ACL-R in Manitoba between 1980 and 2015. Patient factors gathered at time of surgery included: age, sex, urban or rural residence, neighborhood income quintile, and resource utilization band (RUB). Each person was matched with up to 5 people from the general population who had never had ACL-R and had not had a TKR at the time of the case ACL-R. The rate of TKR after ACL-R. Overall from 1980 to 2015, 8500 ACL-R were identified within the 16 to 60 years age group with a resultant 42 497 population matches. Sex was predominantly male. The mean age of the ACL-R group at the time of TKR was 53.7 years, whereas the mean age for the matched cohort was 58.2 years, P < 0.001. Those with ACL-R were 4.85 times more likely to go on to have TKR. Apart from age, no other risk factors examined (location, year of surgery, place of residence, income quintile, and RUB) seemed to increase risk of TKR after ACL-R. Patients who underwent ACL-R were 5 times more likely to undergo TKR.

Aggravation of Ankle Varus Incongruency Following Total Knee Replacement Correcting ≥10° of Genu Varum Deformity: A Radiographic Assessment

BackgroundThis study aimed to investigate the change in ankle varus incongruencies following total knee replacement (TKR) in patients with preoperative genu varum deformity of ≥10°. MethodsThe study cohort was composed of patients who underwent TKR in a single institution for knee osteoarthritis with preoperative genu varum deformity of ≥10° and concomitant varus ankle incongruencies. Eight radiographic measurements were evaluated preoperatively and postoperatively: mechanical tibiofemoral angle, mechanical lateral distal femoral angle, medial proximal tibial angle, lateral distal tibial angle, tibial plafond inclination, talar inclination, tibiotalar tilt angle (TTTA), and tibia-mechanical axis angle. Of these, TTTA represented the quantitative degree of ankle joint incongruency. ResultsA total of 110 patients (male = 2; female = 108) were included in the analysis. The mean patient age was 68.9 (standard deviation [SD] 7.2) years at the time of TKR. All radiographic measurements showed significant changes postoperatively, representing the appropriate correction of genu varum deformity and restoration of the mechanical axis. Nineteen patients (17.3%) showed postoperative decrease in TTTA, 2 (1.8%) remained the same, and 89 (80.9%) showed increase. Overall, mean preoperative and postoperative TTTA were 3.3° (SD 2.2°) and 4.7° (SD 2.9°), respectively (P < .001), representing the aggravation of varus ankle incongruencies. ConclusionVarus ankle incongruencies showed aggravation following TKR despite correction of genu varum deformity and restoration of the mechanical axis. This could be an important cause of postoperative increase or development of ankle pain following TKR. Therefore, patients with preoperative varus ankle incongruencies need to be warned of possible aggravation of ankle symptoms and be evaluated before TKR. Level of EvidencePrognostic level III.

A Microarray Study of Articular Cartilage in Relation to Obesity and Severity of Knee Osteoarthritis.

To query the transcript-level changes in the medial and lateral tibial plateau cartilage in tandem with obesity in patients with end-stage osteoarthritis (OA). Cartilage was obtained from 23 patients (20 obese [body mass index > 30 kg/m2], 3 overweight [body mass index < 30 kg/m2]) at the time of total knee replacement. Cartilage integrity was assessed using Outerbridge scale, while radiographic changes were scored on preoperative X-rays using Kellgren-Lawrence (K-L) classification. RNA was probed for differentially expressed transcripts between medial and lateral compartments using Affymetrix Gene 2.0 ST Array and validated via real-time polymerase chain reaction. Gene ontology and pathway analyses were also queried. Scoring of cartilage integrity by the Outerbridge scale indicated that the medial and lateral compartments were similar, while scoring by the K-L classification indicated that the medial compartment was more severely damaged than the lateral compartment. We observed a distinct transcript profile with >50% of transcripts unique between medial and lateral compartments. MMP13 and COL2A1 were more highly expressed in medial versus lateral compartment. Polymerase chain reaction confirmed expression of 4 differentially expressed transcripts. Numerous transcripts, biological processes, and pathways were significantly different between overweight and obese patients with a differential response of obesity on medial and lateral compartments. Our findings support molecular differences between medial and lateral compartments reflective of the greater severity of OA in the medial compartment. The K-L system better reflected the molecular results than did the Outerbridge. Moreover, the molecular effect of obesity was different between the medial and lateral compartments of the same knee plausibly reflecting the molecular effects of differential biomechanical loading.

Biological reconstruction of varus deformity in primary total knee replacement using bone graft and description of a new technique

Peripheral bony defects of the tibia can be seen in patients with osteoarthritis of the knee. These defects must be corrected at the time of total knee replacement to ensure correct placement and alignment of the components.We describe a new technique for correcting large tibial defect by using bone graft, where the uncontained defects were converted to contained defects using bone graft and the contained defect was impacted with cancellous bone. Between 2006 and 2010, 48 cases of primary total knee arthroplasty were reconstructed using autologous bone graft. Of 48 cases, five cases had large tibial defect and were treated with the new technique. Collapse was seen in one knee at 5 months postoperative. The rest of the patients showed improvement in total knee score and limb alignment.We now use this technique to treat large tibial defect during total knee replacement.

Structural associations of symptomatic knee osteoarthritis.

ObjectiveStructural changes of osteoarthritis (OA) may occur in the absence of pain. In this study, we aimed to identify histopathologic features that are associated with symptomatic knee OA.MethodsMedial tibial plateaus and synovium samples were obtained at the time of total knee replacement (TKR) surgery for OA (advanced OA group) or were obtained postmortem from subjects who had not sought medical attention for knee pain during the last year of life (non-OA control group). To identify features of OA, we compared the patients with advanced OA with the age-matched non-OA controls (n = 26 per group). To identify OA features associated with symptoms, we compared two additional groups of subjects who were matched for severity of chondropathy (n = 29 per group): patients undergoing TKR for symptomatic OA (symptomatic chondropathy group) and postmortem subjects with similar severity of chondropathy who were asymptomatic during the last year of life (asymptomatic chondropathy group). The histologic features of the samples were graded, and immunoreactivities for macrophages (CD68) and nerve growth factor (NGF) in the synovium were quantified. The cellular localization of synovial NGF was determined by double immunofluorescence analysis.ResultsAdvanced OA cases displayed more severe changes in the synovium (synovitis, increased synovial NGF, and CD68-immunoreactive macrophages) and cartilage (loss of cartilage surface integrity, loss of proteoglycan, tidemark breaching, and alterations in chondrocyte morphology) than did the non-OA controls. Synovial NGF was localized predominantly to fibroblasts and to some macrophages. The symptomatic chondropathy group displayed greater levels of synovitis, synovial NGF, and loss of cartilage integrity, in addition to alterations in chondrocyte morphology, than did the asymptomatic chondropathy group (P < 0.05 for each comparison).ConclusionSynovitis, increased synovial NGF, alterations in chondrocyte morphology, and loss of cartilage integrity are features of knee OA that may be associated with symptoms.

Gene expression pattern of cells from inflamed and normal areas of osteoarthritis synovial membrane.

ObjectiveTo compare the gene expression patterns of synovial cells from inflamed or normal/reactive areas of synovial membrane obtained from the same patient with osteoarthritis (OA).MethodsAt the time of total knee replacement, synovial tissues were obtained from 12 patients with knee OA. The inflammation status of the synovial membrane was characterized according to macroscopic criteria and classified as normal/reactive or inflamed. Biopsy samples were cultured separately for 7 days. Microarray gene expression profiling was performed on normal/reactive and inflamed areas. Western blot and immunohistochemistry were used to confirm the identified genes that were differentially expressed.ResultsWe identified 896 genes that were differentially expressed between normal/reactive and inflamed areas. The key pathways were related to inflammation, cartilage metabolism, Wnt signaling, and angiogenesis. In the inflammation network, the genes TREM1 and S100A9 were strongly up-regulated. The genes MMP3, MMP9, CTSH (cathepsin H), and CTSS (cathepsin S) were significantly up-regulated in the cartilage catabolism pathway, while the most up-regulated anabolism enzyme gene was HAS1. In the Wnt signaling pathway, the genes for Wnt-5a and low-density lipoprotein receptor–related protein 5 were up-regulated, while the gene FZD2 and the gene for Dkk-3 were down-regulated. Finally, STC1, which codes for a protein involved in angiogenesis, was identified as the most up-regulated gene in inflamed compared with normal/reactive areas.ConclusionThis study is the first to identify different expression patterns between 2 areas of the synovial membrane from the same patient. These differences concern several key pathways involved in OA pathogenesis. This analysis also provides information regarding new genes and proteins as potential targets of treatment.

AB1052 Revisiting chemical and morphological diversity of calcium-containing crystals in human osteoarthritic menisci

BackgroundCalcium-containing crystals (CC), including basic calcium phosphate crystals (BCPs) and calcium pyrophosphate crystals (CPPs) are associated with destructive forms of osteoarthritis (OA). Recent reports support that mineralization of several joint...

Revisiting spatial distribution and biochemical composition of calcium-containing crystals in human osteoarthritic articular cartilage

IntroductionCalcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage.MethodsWe prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients.ResultsMean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages.ConclusionsCaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process.

Effect of Different Irrigation Fluids on Human Articular Cartilage: An In Vitro Study

The goal of this study was to examine the effect of different irrigation fluids on human articular cartilage. Femoral heads were obtained from 9 patients with fractured neck of femur (mean age, 89 years; 7 female) and tibial plateaus from 2 female patients at the time of total knee replacement (mean age, 73 years). Chrondral explants were harvested and exposed to 1 of 4 different irrigation fluids for 1 hour: Ringer's solution, normal saline (0.9% NaCl), 1.5% glycine, or 5% mannitol. M199 culture medium was used as a positive control, and 0.5% bupivicaine, previously shown to be harmful to articular cartilage, as a negative control. After exposure, explants were incubated with radiolabeled sulfate ((35)S0(4)), and uptake was measured after 16 hours as an indicator of proteoglycan synthesis. (35)S0(4) uptake was inhibited 10% by Ringer's solution (P= .3), 24% by 1.5% glycine (P= .08), 31% by 5% mannitol (P= .03), 35% by normal saline (P= .04), and 90% by 0.5% bupivacaine (P < .001), compared with the M199 control. Comparisons of the different solutions showed that all solutions were less inhibitory than 0.5% bupivacaine (P < .001). The only significant difference was that between normal saline and Ringer's solution (P= .03). In an in vitro model of human articular cartilage, Ringer's solution had the least effect on cartilage metabolism, and normal saline caused the greatest inhibition of cartilage metabolism. Normal saline, the most commonly used irrigation fluid, may have an inhibitory effect on proteoglycan metabolism in articular cartilage. Additional studies are required to assess the potential damage to cartilage from normal saline in the clinical setting.

Reemplazo total de rodilla en gonartrosis asociada a deformidad extraarticular

&lt;p&gt;&lt;strong&gt;Introducción:&lt;/strong&gt;El éxito a largo plazo de un reemplazo total de rodilla (RTR) depende de la restitución del eje mecánico del miembro, de la correcta colocación del implante y del balance de partes blandas. Los pacientes con gonartrosis asociada a una deformidad extraarticular, femoral o tibial, requieren de una cuidadosa evaluación y planificación preoperatoria con el objeto de decidir si la corrección del eje podrá realizarse mediante la resección ósea intraarticular, o si deberá asociarse una osteotomía extraarticular.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Material y Método:&lt;/strong&gt;Se evaluaron 22 RTR (en 20 pacientes) por gonartrosis asociada a deformidad extraarticular. La etiología de la deformidad extraarticular fue postraumática en 8 casos y postosteotomía en 14 (8 femorales y 6 tibiales).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Resultados:&lt;/strong&gt;En todos los casos se realizó la corrección del eje del miembro mediante un RTR con cortes óseos intra articulares “inusuales”, sin que fuera necesario realizar una osteotomía. La evaluación clínica y funcional se realizó mediante el sistema de puntaje de la Knee Society&lt;sup&gt;2&lt;/sup&gt;. El promedio de la evaluación clínica fue de 24,3 puntos en el prequirúrgico y 86 al año postoperatorio. Con respecto al puntaje funcional, paso de un promedio de 34 puntos en el prequirúrgico a 85,3 puntos al año.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusión:&lt;/strong&gt;No hay un criterio único en relación al tratamiento del paciente con gonartrosis sintomática asociada a una deformidad extraarticular. La corrección de la deformidad extraarticular por medio de cortes óseos intraarticulares ¨inusuales¨ es posible si estos no afectan las inserciones ligamentarias femorales ni tibiales. Este método puede aplicarse en desejes femorales de hasta 20° y tibiales de hasta 30° en el plano coronal. Mediante esta técnica hemos obtenido buenos resultados, a más de 5 años de seguimiento, en 20 de los 22 casos operados.&lt;/p&gt;

Fewer and older patients with rheumatoid arthritis need total knee replacement

Objectives: Recent studies have suggested a decreased need for orthopaedic surgery in patients with rheumatoid arthritis (RA). We analysed trends in total knee replacement (TKR) in RA using TKR in osteoarthritis (OA) as a point of reference.Methods: Data on TKRs from the Finnish Arthroplasty Register and population data from Statistics Finland were used to analyse the trends in TKRs among patients aged ≥ 40 years with primary osteoarthritis (OA) or RA in Finland for the period from 1980 to 2010.Results: During 1980–2010, the overall incidence of TKRs increased 20-fold from 14.2 to 305.3 operations per 105 person-years. After peaking in 1992, the annual incidence of TKRs for RA decreased gradually from 19.6 to 10.8 per 105 [incidence rate ratio (IRR) 0.97, p < 0.001]. The decrease was more pronounced in women and the older (≥ 60 years) age group. The mean age at the time of TKR among patients with RA increased over time, converging with that of patients with OA.Conclusion: There is a clear decrease in the annual incidence of TKRs in RA, while among OA patients the incidence is increasing steadily. Furthermore, patients with RA seem to receive their TKRs at an older age. Both of these findings suggest improving long-term outcome in RA.

A case-control study of spontaneous patellar fractures following primary total knee replacement

Peri-prosthetic patellar fracture following resurfacing as part of total knee replacement (TKR) is an infrequent yet challenging complication. This case-control study was performed to identify clinical, radiological and surgical factors that increase the risk of developing a spontaneous patellar fracture after TKR. Patellar fractures were identified in 74 patients (88 knees) from a series of 7866 consecutive TKRs conducted between 1998 and 2009. After excluding those with a previous history of extensor mechanism realignment or a clear traumatic event, a metal-backed patella, any uncemented component or subsequent infection, the remaining 64 fractures were compared with a matched group of TKRs with an excellent outcome defined by the Knee Society score. The mean age of patients with a fracture was 70 years (51 to 81) at the time of TKR. Patellar fractures were detected at a mean of 13.4 months (2 to 84) after surgery. The incidence of patellar fracture was found to be strongly associated with the number of previous knee operations, greater pre-operative mechanical malalignment, smaller post-operative patellar tendon length, thinner post-resection patellar thickness, and a lower post-operative Insall-Salvati ratio. An understanding of the risk factors associated with spontaneous patellar fracture following TKR provides a valuable insight into prevention of this challenging complication.

Inflammation related to synovectomy during total knee replacement in patients with primary osteoarthritis

We compared inflammation in the knee after total knee replacement (TKR) for primary osteoarthritis between two groups of patients undergoing joint replacement with and without synovectomy. A total of 67 patients who underwent unilateral TKR were randomly divided into group I, TKR without synovectomy, and group II, TKR with synovectomy. Clinical outcomes, serial serum inflammatory markers (including interleukin-6 (IL-6), CRP and ESR) and the difference in temperature of the skin of the knee, compared with the contralateral side, were sequentially evaluated until 26 weeks after surgery. Pre-operatively, there were no statistically different clinical parameters between groups I and II. At the 26-week follow-up, both groups had a similarly significantly improved American Knee Society clinical score (p < 0.001) and functional score (p < 0.001) with no differences between the groups. Similar changes in serial inflammatory markers were found in both groups, including mean peak levels of IL-6 (189 pg/ml (SD 53.4) versus 201 pg/ml (SD 49.4) for groups I and II, respectively) and CRP (91 mg/L (SD 24.1) versus 88 mg/L (SD 23.4), respectively) on the first post-operative day, returning to pre-operative values at two and six weeks, respectively. The mean peak level of ESR for the respective two groups was 46 mm/hr versus 48 mm/hr at two weeks, which had still not returned to its pre-operative mean value at 26 weeks. The elevation in the skin temperature appeared to mirror the peak elevation of the ESR, with a range of 2.5° C to 4.5° C with some reduction at 26 weeks but still exceeding the pre-operative value. We concluded that synovectomy at the time of TKR does not provide any benefit to the clinical outcome or shorten the duration of the inflammatory response after surgery.

The Effect of Total Knee Arthroplasty on Lower Limb Blood Flow

Acute arterial injury at the time of total knee replacement (TKR) is a rare occurrence. We questioned whether TKR could exacerbate preexisting atherosclerotic disease causing chronic limb ischemia. Thirty-three patients undergoing unilateral TKR had the peripheral arterial supply of both legs assessed 2 weeks before and 6 weeks after the operation using various methods. Although a statistically significant reduction in the velocity ratio was measured in the trial leg, 0.92 (0.33) as compared to the control, 1.11 (0.46) ( P = .0002) this was not found to be clinically significant when the minimum popliteal artery diameter of the trial limb, 6.23 (1.32), was compared with the control, 6.28 (1.27) ( P = .8246). Neither were significant reductions in arterial waveforms or ABPIs measured in the trial legs preoperatively, 0.97 (0.20), and postoperatively, 0.93 (0.27) ( P = .2793). TKR does not impair the arterial supply of the limb at 6-week postoperative period.

On the Horizon From the ORS

On the Horizon From the ORS

On the Horizon From the ORS

On the Horizon From the ORS

Patellar Resurfacing in Total Knee Arthroplasty

Background: Anterior knee pain following total knee arthroplasty is a common complaint and typically is attributed to the patellofemoral joint. The purpose of the present study was to compare the outcome of resurfacing and nonresurfacing of the patella, particularly with regard to anterior knee pain, and to clarify the indications for patellar resurfacing at the time of total knee arthroplasty. Methods: We performed a prospective, randomized study of 514 consecutive primary press-fit condylar total knee replacements. The patients were randomized to either resurfacing or retention of the patella. They were also randomized to either a cruciate-substituting or a cruciate-retaining prosthesis as part of a separate trial. The mean duration of follow-up was 5.3 years (range, two to 8.5 years), and the patients were assessed with use of the Knee Society rating, a clinical anterior knee pain score, and the British Orthopaedic Association patient-satisfaction score. The assessment was performed without the examiner knowing whether the patella had been resurfaced. At the time of follow-up, there were 474 knees. Thirty-five patients who had a bilateral knee replacement underwent resurfacing on one side only. Results: The overall prevalence of anterior knee pain was 25.1% (fifty-eight of 231 knees) in the nonresurfacing group, compared with 5.3% (thirteen of 243 knees) in the resurfacing group (p < 0.0001). There was one case of component loosening. Ten of eleven patients who underwent secondary resurfacing had complete relief of anterior knee pain. The overall postoperative knee scores were lower in the nonresurfacing group, and the difference was significant among patients with osteoarthritis (p < 0.01). There was no significant difference between the resurfacing and nonresurfacing groups with regard to the postoperative function score. Patients who had a bilateral knee replacement were more likely to prefer the resurfaced side. Conclusions: As the present study showed a significantly higher rate of anterior knee pain following arthroplasty without patellar resurfacing, we recommend patellar resurfacing at the time of total knee replacement when technically possible. Level of Evidence: Therapeutic study, Level I-1a (Randomized controlled trial [significant difference]). See Instructions to Authors for a complete description of levels of evidence.

The anatomic origin of the posterior cruciate ligament: where is it? Reference landmarks for PCL reconstruction.

There is a lack of defined reference points for reproducible femoral tunnel placement during posterior cruciate ligament (PCL) reconstruction. The PCL, consisting of two major bands, anterolateral (AL) and posteromedial (PM), has a femoral origin that spans 3 cm, which cannot be covered by a substitute graft positioned in one femoral tunnel to reconstruct the PCL. The purpose of this study was to define the location of the anatomic origin of both bands of the PCL in reference to local anatomy to develop landmarks that can be used to reproducibly position two femoral tunnels (one to each band's origin) during PCL reconstruction. The anatomy of the PCL origin was dissected and studied in 20 knees at the time of total knee replacement. The central origin point for each band was marked, and its distance was measured in reference to three axes. The AL band centrally originated 13 +/- 0.5 mm posterior to the medial articular cartilage-intercondylar wall interface and 13 +/- 0.5 mm inferior to the articular cartilage-intercondylar roof interface. The PM band centrally originated 8 +/- 0.5 mm posterior to the medial articular cartilage-intercondylar wall interface and 20 +/- 0.5 mm inferior to the articular cartilage-intercondylar roof interface. These distances were noted to be relatively constant despite varying knee morphologies and size. For this reason, referencing the articular cartilage-intercondylar roof, and wall interfaces may be used as a method to facilitate more reproducible anatomic femoral tunnel placements during PCL reconstruction.