Time Of Total Knee Arthroplasty Research Articles

The extent of degeneration of cruciate ligament is associated with chondrogenic differentiation in patients with osteoarthritis of the knee

Degeneration in cruciate ligaments results from abnormal biomechanical stress and the aging process. Such degeneration is a common outcome in patients with osteoarthritis (OA) of the knee and contributes to the progression of OA. However, to date, there are no specific markers that can predict the extent of ligament degeneration. We hypothesized that the extent of degeneration has correlations to increased chondrogenic potential. Twenty anterior cruciate ligaments (ACLs) and 30 posterior cruciate ligaments (PCLs) from 30 knees of 28 adult patients with OA at the time of total knee arthroplasty were used for the study. Degeneration was histologically assessed using a grading system. Expressions of Scleraxis (as a ligament cell marker) and Sry-type HMG box 9 (SOX9) (as a chondrogenic marker) were immunohistochemically assessed in each grade. We found the opposite expression pattern between Scleraxis and SOX9 according to the grade. The percentage of Scleraxis-positive cells decreased significantly by grade (60.9±23.7 in grade 1, 39.7±30.5 in grade 2, and 13.9±27.1 in grade 3, P<0.0001). In contrast, the percentage of SOX9-positive cells increased significantly by grade (2.5±4.9 in grade 1, 17.5±13.4 in grade 2, and 50.9±27.1 in grade 3, P<0.0001). Furthermore, co-localized expression of both Scleraxis and SOX9 was demonstrated in chondrocyte-like cells. This study indicates that chondrogenic differentiation is associated with the progression of degeneration in human ligaments. Our results suggest that the expression of SOX9 as a chondrogenic marker could be an indicator for the extent of degeneration in human ligaments. It remains to be elucidated whether suppression of chondrogenic differentiation can prevent progression of the degenerative process of cruciate ligaments in patients with OA.

Osteoprotegerin expression in bone marrow by treatment with tocilizumab in rheumatoid arthritis

The aim of this study was to investigate histological changes of bone marrow in response to tocilizumab for rheumatoid arthritis (RA). After tocilizumab therapy, bone marrow tissues were extracted from ten RA patients at the time of total knee arthroplasty (TKA). Control samples were obtained from ten RA patients who underwent MTX mono-therapy. Histological examination of structural differences between the tocilizumab and control groups in bone marrow was performed using hematoxylin and eosin (H&E) to evaluate differences. In immunohistochemical examination, the expression of seven molecules including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), CD68, osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL), CD4 and osteopontin (OPN) were compared between two groups. NTx was significantly low at 44.5 ± 2 nM BCE/mM Cr compared with control at 73.2 ± 8 nM BCE/mM Cr. Immunohistochemical examination revealed that the bone marrow tissues of the RA patients who underwent tocilizumab therapy demonstrated significant positive OPG as compared with the control. However, immunohistochemical examinations after tocilizumab revealed that TNF-α, IL-6, CD68, CD4, OPN and RANKL were not significantly different with control of MTX in bone marrow. Therefore, treatment with tocilizumab increased the expression of OPG as the histological changes with respect to inhibit RANKL-related bone resorption of bone marrow in RA.

Prophylactic Flap Reconstruction of the Knee Prior to Total Knee Arthroplasty in High-Risk Patients

Insufficient soft-tissue coverage following total knee arthroplasty (TKA) may threaten prosthesis retention or compromise joint function. A retrospective review was conducted of all patients who underwent prophylactic flap reconstruction of the knee prior to TKA or salvage flap reconstruction over a 6-year period. Twenty-three patients underwent prophylactic flap reconstruction. Complications at the time of flap transfer were common (48%), however, all flaps survived. All 23 successfully completed subsequent TKA with no wound complications occurring at the time of TKA. Complications in the salvage group were also frequent (44%) and 3 required above knee amputation. Postoperative range of motion was significantly better in the prophylactic group, as well as when cutaneous flaps were chosen. Prophylactic flap reconstruction of the knee prior to TKA in high-risk patients is an excellent option in this small subset of patients, many of whom would not be offered TKA without addressing the compromised soft-tissue envelope first.

The middle and long clinical results of patellofemoral arthroplasty for severe patellofemoral osteoarthritis

Objective To evaluate the clinical significance, and middle and long clinical outcomes of patellofemoral arthroplasty for the treatment of severe patellofemoral osteoarthritis. Methods Between January 1991 to July 1999, we studied retrospectively the outcomes of patellofemoral arthroplasty using the prosthesis (type Y-L-Q) designed by us in 39 patients (48 knee joints) with severe patellofemoral os-teoarthritis. There were 6 males (6 knee joints) and 33 females (42 knee joints) with a mean age of 54.4 years (range, 38 to 68 years). The patients were followed up at 3, 6, 12 months and subsequent years (per year) after operation. The evaluate standard was designed by us, which mainly included the symptoms of the patients and the functions of the knee joints. Results All the patients were followed up for average 12.7 years (range, 8 to 16 years). The last follow-up showed the clinical outcomes were: excellent in 29 knees, good in 12, acceptable in 2 and bad in 5. The excellent and good rate was 85.4%.There was no loosening or breakage of the prosthesis and no patellar fracture. 3 patients (5 knee joints) were performed total knee arthroplasty due to the degenerative progression of the knee joints, in which accounted for 10.4%. The mean time interval between the patellofemoral arthroplasty and total knee arthroplasty was 9.3 years (range, 7 to 12 years). Conclusion Patellofemoral arthroplasty with the prosthesis designed by us was a simple and effec-tive method for the severe isolated patellofemoral osteoarthritis. It could not only eliminate the pain of patel-la, but also delay the time of total knee arthroplasty. Key words: Osteoarthritis, knee; Arthroplasty, replacement, knee; Prosthesis design

Key factors in determining surgical timing of total knee arthroplasty in osteoarthritic patients: age, radiographic severity, and symptomatic severity

BackgroundPatient age, radiographic severity of osteoarthritis (OA), and severity of symptoms are typically considered as the three key factors in selecting the osteoarthritic patients for total knee arthroplasty (TKA). The purpose of this study was to evaluate the associations between the three selection criteria and the postoperative outcomes including patient satisfaction. We also attempted to determine whether the patients not fully satisfying the criteria are different from the typical candidates in postoperative outcomes.Materials and methodsThree hundred and eighty-three uncomplicated TKAs with 1-year follow-up data were included in this study. We evaluated three preoperative factors including age, radiographic severity of OA, and WOMAC pain and function scores as proxies of preoperative level of symptoms. Evaluation of the postoperative outcomes included WOMAC pain and function scores and the level of patient satisfaction. Regression analyses were used to investigate the associations between the preoperative factors and the postoperative outcomes. Comparative analyses of the postoperative outcomes were made between the typical candidates with all selection criteria and the groups of patients who did not meet one of the selection criteria.ResultsIncreasing age was associated with worse postoperative functional outcomes. Worse preoperative WOMAC pain and function scores were associated with worse postoperative WOMAC pain and function scores, and had a statistical tendency toward higher patient dissatisfaction. Compared to the typical candidates, the groups of patients who did not meet one of the selection criteria did not have worse postoperative outcomes. On the contrary, the group of younger age and the group with less severe preoperative symptoms were more likely to have better postoperative outcomes. The radiographic severity of OA had no significant associations with any of postoperative outcomes.ConclusionThis study indicates that, when considering TKA as a treatment option, orthopedic surgeons need to comprehend the selection criteria in an overall view to offer the best timing for optimal postoperative outcomes.

Using VistA Electronic Medical Record Data Extracts to Calculate the Waiting Time for Total Knee Arthroplasty

This is a retrospective database study of veterans who had total knee arthroplasty (TKA) at Veterans Affairs Connecticut Healthcare System. The objective of this study is to determine if VistA medical records data can be used to create a methodology for accurate assessment of waiting times for TKAs performed at Veterans Affairs facilities. The average waiting period from date of “initial consult” to date TKA was performed was greater than two years. The average waiting period from “most recent consult” to TKA was less than a year. This new approach and methodology has great impact as it provides an electronic method for calculating the TKA wait time which is broadly generalizable for similar analysis at the VISN (Veteran Integrated Services Network) or regional level.

Detection of pain-related molecules in the subchondral bone of osteoarthritic knees

Knee pain is predominant among osteoarthritis (OA) patients, but the mechanism is poorly understood. We investigated subchondral bone as a source of OA knee pain using immunohistochemistry. Fifteen medial-type OA knees with minimum involvement of the lateral compartment determined by X-ray as well as magnetic resonance imaging that received total knee arthroplasty (TKA) were involved. Each pair of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) was compared obtained at the time of TKA. Osteocartilaginous MFC and LFC specimens were histologically examined and stained with antibodies against cyclooxygenase 1 (Cox-1), cyclooxygenase 2 (Cox-2), substance P, tumor necrosis factor-alpha (TNF-alpha), and neuron-specific class III beta-tubulin (TUJ1), a pan-neuronal marker. Formation of cystic lesions was more frequently seen in the MFC. The lesions were composed of vascular endothelial cells, osteoclasts, and mononuclear cells and were present in similar proportions between the MFC and the LFC. Four out of 15 MFC specimens were positive for Cox-1, 15 for Cox-2, and 13 for TNF-alpha. No LFC specimens were positive for any antibodies. Substance P-positive and TUJ1-positive fibers were found in the subchondral area of the MFC, but not in the LFC. Pathological changes in the subchondral bone can be a source of knee pain, which was detectable by the positive immunoreactivity of substance P, Cox-2, TNF-alpha, and TUJ1, in the subchondral bone of affected compartments. The relatively immediate reduction in pain obtained by TKA might account for the involvement of the subchondral bone in knee pain because most of the affected subchondral plate is excised in TKA (debridement effect of TKA).

Total Knee Arthroplasty After Patellectomy

The techniques for total knee arthroplasty in patients who have undergone previous patellectomy are limited in their description. This report briefly reviews the historical and current indications for patellectomy, describes the biomechanics of the patella as well as patella-deficient knees, and presents the techniques and previously reported results for patellar reconstruction at the time of total knee arthroplasty including autograft bone reconstruction, allograft implantation, and the use of a prosthetic patella. While the reported results are limited to a small number of patients, it appears that patellar reconstruction at the time of total knee arthroplasty can provide successful results in appropriately selected patients.

Geranylgeranylacetone, a non-toxic inducer of heat shock protein, induces cell death in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Fluvastatin (Fluv) is reported to induce apoptosis in rheumatoid arthritis (RA) synoviocytes through the blocking of protein geranylgeranylation. We report here our investigation of whether geranylgeranylacetone (GGA) induces cell death in RA synoviocytes. Synovial tissues were obtained from patients with RA at the time of total knee arthroplasty. Fibroblast-like synoviocytes (FLS) cultured in three passages were used for the experiments. The FLS were then cultured for 48 h in 48-well flat-bottomed plates containing various concentrations of GGA (0.1–4.0 μg/ml) and either 0.1 or 0.5 μM Fluv. We also examined the effect of GGA and Fluv in human fibroblasts from normal skin (CCD-25SK) and FLS from patients with osteoarthritis (OA). Cells demonstrating cell death were counted following trypan blue staining. In the absence of GGA, there was no apparent cell death, as evidence by trypan blue staining. Concentrations of GGA between 0.1 and 4.0 μg/ml induced cell death in RA FLS, but not in skin fibroblasts (CCD-25SK) nor OA FLS. The number of synoviocytes demonstrating cell death induced by 0.1 or 0.5 μM Fluv was significantly higher than that by the medium alone. In summary, we found that GGA induced cell death in RA FLS, suggesting that GGA may be a potential new therapeutic agent for RA as well as osteoporosis.

Geranylgeranylacetone, a non-toxic inducer of heat shock protein, induces cell death in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Fluvastatin (Fluv) is reported to induce apoptosis in rheumatoid arthritis (RA) synoviocytes through the blocking of protein geranylgeranylation. We report here our investigation of whether geranylgeranylacetone (GGA) induces cell death in RA synoviocytes. Synovial tissues were obtained from patients with RA at the time of total knee arthroplasty. Fibroblast-like synoviocytes (FLS) cultured in three passages were used for the experiments. The FLS were then cultured for 48 h in 48-well flat-bottomed plates containing various concentrations of GGA (0.1-4.0 microg/ml) and either 0.1 or 0.5 microM Fluv. We also examined the effect of GGA and Fluv in human fibroblasts from normal skin (CCD-25SK) and FLS from patients with osteoarthritis (OA). Cells demonstrating cell death were counted following trypan blue staining. In the absence of GGA, there was no apparent cell death, as evidence by trypan blue staining. Concentrations of GGA between 0.1 and 4.0 microg/ml induced cell death in RA FLS, but not in skin fibroblasts (CCD-25SK) nor OA FLS. The number of synoviocytes demonstrating cell death induced by 0.1 or 0.5 microM Fluv was significantly higher than that by the medium alone. In summary, we found that GGA induced cell death in RA FLS, suggesting that GGA may be a potential new therapeutic agent for RA as well as osteoporosis.

Flexion Contractures: Getting It Straight

The importance of correcting soft tissue imbalance at the time of total knee arthroplasty is well recognized. Fixed knee flexion contractures are common preoperatively and can make balancing more challenging for the surgeon. In addition, restoration of full passive knee extension is required at the time of total knee arthroplasty to achieve optimal function. The objective of this article is to give the reader a stepwise approach, based on the degree of flexion contracture, to effectively attain full extension in the operating room.

Bikondylärer Oberflächenersatz - Einfluss präoperativer Funktionseinschränkungen auf das frühfunktionelle postoperative Outcome

The point of time for total knee arthroplasty has a significant importance due to limited implant survival rate. To what extent the preoperative stage of physical and psychological function limitation, which is increasing with the progression of the osteoarthritis, has an influence on the early functional outcome after total knee arthroplasty should be clarified in a clinical evaluation. 47 Patients were treated with the same bicondylar knee endoprosthesis system (Type Genia, ESKA Implants, Lübeck). A clinical evaluation was undertaken preoperatively and at 3 and 6 months postoperatively using HSS score, WOMAC index and SF-36 score. In relation to the preoperative HSS score the patients were allocated into three groups depending upon whether their level of function was "good", "average" or "poor". Additionally, all patients were assigned to three body mass index (BMI) groups (< 30, 30 - 35, > 35) which were descriptively analysed. The preoperative differences in HSS score and SF-36 score in all three groups show a high reduction after 3 and 6 months. Postoperatively there were no significant differences in all three groups at both timepoints. Patients with "poor" preoperative function achieved on average a lower score niveau than patients with preoperative "good" function, but have the benefit of the best function improvement. The early postoperative period (3 months) showed the highest decrease in physical and psychological function derogation. The BMI had no significant influence on the early functional outcome. Therefore, older people should receive early total knee arthroplasty to gain a high postoperative score niveau. In younger patients the indication for implant should be considered essentially because of the limited survival rate. Even in progressive osteoarthritis and extreme functional limitation the bicondylar surface replacement gives the possibility of a good early functional postoperative outcome. Total knee arthroplasty of obese patients is under attention of the perioperative internistic risks, a safe procedure with good functional results and can increase patient's mobility.

Relationship Between Knee Anthropometry and Surgical Time in Total Knee Arthroplasty in Severely and Morbidly Obese Patients: A New Prognostic Index of Surgical Difficulty

Total knee arthroplasty (TKA) in patients with severe and morbid obesity is one of the current challenges in prosthetic knee surgery. The body mass index (BMI) is used to identify patients who may present difficulties during surgery and postoperative complications. We carried out a prospective study with an initial hypothesis that BMI is not associated with tourniquet time in obese patients undergoing TKA and that some anthropometric parameters may be useful in predicting tourniquet time in severely and morbidly obese patients. One hundred consecutive patients diagnosed with knee osteoarthritis with BMI > or =35 kg/m(2) scheduled for TKA were prospectively studied. Suprapatellar, infrapatellar, and supra/infrapatellar anthropometric indexes were calculated before surgery. The tourniquet time was determined. The mean BMI was 39.81 kg/m(2) (SD +/- 3.75). A total of 58% of patients were classified as class III obesity (BMI 35-39.99) and 42% as class IV (BMI > or = 40) Mean tourniquet time was 41.67 min (SD +/- 9.26). There was no association between the BMI and tourniquet time. The suprapatellar index was negatively associated with tourniquet time (p < 0.038). The BMI is not the only parameter that should be considered in order to identify severely and morbidly obese patients who may have more surgical difficulties during TKA. Preoperative determination of the suprapatellar index helped us to classify these patients according to the morphology of the knee and predicted a longer tourniquet time and, therefore, greater surgical difficulty, in patients with a suprapatellar ratio below 1.6 in this study.

Histological changes in bone marrow after treatment of infliximab for rheumatoid arthritis

To investigate histological evidence of bone remodeling in response to infliximab for rheumatoid arthritis (RA), bone marrow tissues were extracted from ten RA patients at the time of total knee arthroplasty after treatment of infliximab for an average of 16 months (range, 8-24 months). The patients had a mean age of 65.3 years (range, 57-76 years) with 4.8 mg/week of methotrexate (MTX; 4-6 mg) and 3.8 mg/day of prednisolone (2-5 mg). Control samples were obtained from ten RA patients who did not undergo infliximab therapy. These patients had an average age of 67.6 years (range, 59-78 years) and received 5.2 mg/week of MTX (4-6 mg) and 4.0 mg/day of prednisolone (2-5 mg). Histological examination of structural differences between the infliximab and control groups in bone marrow was performed using hematoxylin and eosin (H & E) to evaluate differences. In immunohistochemical examination, the expressions of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), receptor activator of nuclear (kappa) B ligand (RANKL), osteoprotegerin (OPG), and osteopontin (OPN) were compared between both groups. H & E staining revealed that the bone marrow tissues of the RA patients who underwent infliximab therapy demonstrated newly formed thickness of interstitial septum among the trabeculae as compared with the control group. Moreover, immunohistochemical examinations revealed that TNF-alpha, IL-6, RANKL, OPG, and OPN were expressed in this newly formed bone after infliximab therapy. Therefore, treatment with infliximab improved the histological changes with respect to bone metabolism in the newly formed bone marrow tissues.

The Effect of Stuffing the Patellofemoral Compartment on the Outcome of Total Knee Arthroplasty

The effect of so-called stuffing of the patellofemoral compartment at the time of total knee arthroplasty (that is, increasing the anterior patellar displacement, the anteroposterior femoral size, or the combined anteroposterior patellofemoral size) has not been well studied. The purpose of the present study was to evaluate the effect of stuffing the patellofemoral compartment on the outcome of primary total knee arthroplasty. A retrospective review of 1100 primary total knee arthroplasties that had been performed in 1997 and 1998 was conducted. Eight hundred and thirty arthroplasties (75.5%) met the diagnostic and minimum two-year follow-up criteria for inclusion in this report. Radiographic measurements were made to determine preoperative and postoperative anterior patellar displacement, anteroposterior femoral size, combined anteroposterior patellofemoral size, anterior femoral offset, and posterior femoral offset. Regression analysis was performed to determine the effects of changes in these variables on the range of motion, the Knee Society Knee Score, the Knee Society Function Score, the Knee Society Pain Score, and the rate of lateral retinacular release. Preoperative to postoperative changes in anterior patellar displacement, anteroposterior femoral size, combined anteroposterior patellofemoral size, anterior femoral offset, and posterior femoral offset had no clinically meaningful effect on the range of motion of the knee or on any of the Knee Society scores. Increases in anterior patellar displacement were associated with a lower probability of the need for a lateral retinacular release. Increases in measured anteroposterior femoral size were associated with a higher probability of the need for lateral release. Even when combined, however, these relationships explained only 10.1% of the observed variance in the need for lateral retinacular release. Moreover, analyses indicated that patient gender, large as opposed to medium patellar size, and absolute femoral component size influenced the likelihood of lateral release more than did anterior patellar displacement and measured anteroposterior femoral size. Our findings do not support the widely held belief that stuffing of the patellofemoral joint results in adverse outcomes after total knee arthroplasty. Furthermore, the need for lateral release appears to be multifactorial and likely involves a more complex set of factors. Thus, without evidence of other identifiable causes of failure, we do not recommend revision for the treatment of pain of an overstuffed knee joint.

The Effect of Stuffing the Patellofemoral Compartment on the Outcome of Total Knee Arthroplasty

Background: The effect of so-called stuffing of the patellofemoral compartment at the time of total knee arthroplasty (that is, increasing the anterior patellar displacement, the anteroposterior femoral size, or the combined anteroposterior patellofemoral size) has not been well studied. The purpose of the present study was to evaluate the effect of stuffing the patellofemoral compartment on the outcome of primary total knee arthroplasty. Methods: A retrospective review of 1100 primary total knee arthroplasties that had been performed in 1997 and 1998 was conducted. Eight hundred and thirty arthroplasties (75.5%) met the diagnostic and minimum two-year follow-up criteria for inclusion in this report. Radiographic measurements were made to determine preoperative and postoperative anterior patellar displacement, anteroposterior femoral size, combined anteroposterior patellofemoral size, anterior femoral offset, and posterior femoral offset. Regression analysis was performed to determine the effects of changes in these variables on the range of motion, the Knee Society Knee Score, the Knee Society Function Score, the Knee Society Pain Score, and the rate of lateral retinacular release. Results: Preoperative to postoperative changes in anterior patellar displacement, anteroposterior femoral size, combined anteroposterior patellofemoral size, anterior femoral offset, and posterior femoral offset had no clinically meaningful effect on the range of motion of the knee or on any of the Knee Society scores. Increases in anterior patellar displacement were associated with a lower probability of the need for a lateral retinacular release. Increases in measured anteroposterior femoral size were associated with a higher probability of the need for lateral release. Even when combined, however, these relationships explained only 10.1% of the observed variance in the need for lateral retinacular release. Moreover, analyses indicated that patient gender, large as opposed to medium patellar size, and absolute femoral component size influenced the likelihood of lateral release more than did anterior patellar displacement and measured anteroposterior femoral size. Conclusions: Our findings do not support the widely held belief that stuffing of the patellofemoral joint results in adverse outcomes after total knee arthroplasty. Furthermore, the need for lateral release appears to be multifactorial and likely involves a more complex set of factors. Thus, without evidence of other identifiable causes of failure, we do not recommend revision for the treatment of pain of an overstuffed knee joint. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Anatomy of the Extensor Mechanism in Reference to Quadriceps-sparing TKA

The introduction of minimally invasive surgical techniques in total joint arthroplasty has ushered in a range of new terminology that often is unclear. One such term is quadriceps-sparing total knee arthroplasty (TKA). We examined 100 knees intraoperatively in 100 patients at the time of TKA, dissected 45 entire cadaveric leg specimens, and did high-resolution 3-Tesla magnetic resonance imaging scans on five normal knees to specifically determine: (1) the distal most insertion point of the vastus medialis obliquus; (2) the angle of insertion of the vastus medialis obliquus; and (3) the length of the vastus medialis obliquus tendon. The medial anatomy of the extensor mechanism was consistent. The inferior edge of the VMO inserted at or near the midpole of the patella in each case. The tendon inserted at 50 degrees (range, 46 degrees - 52 degrees). One hundred of the 150 patients (66%) had a tendon that measured 1.2 +/- 0.1 cm, whereas 50 of 150 patients (33%) had a substantially longer tendon (2.2 +/- 0.2 cm). Any medial arthrotomy that extends more proximal than the midpole of the patella detaches a portion of the quadriceps tendon. The term "quadriceps sparing" should not be applied to any surgical approach with a capsular incision that extends more proximal than the midpole of the patella.

Correcting Lateral Patellar Tilt at the Time of Total Knee Arthroplasty Can Result in Overuse of Lateral Release

Ninety-nine patients undergoing primary total knee arthroplasty were prospectively evaluated for pre-resurfacing and post-resurfacing patellar thickness and medial patellar liftoff at 30° of flexion without manual pressure on the patella. Regardless of medial patellar liftoff, no lateral releases were performed. Tibiofemoral angles, patellar tilt, and patellar congruence angles were measured preoperatively and postoperatively. There were no patellar subluxations, dislocations, or complications related to the patellofemoral joint. Patellar tilt improved from 7.9° preoperatively to 3.8° postoperatively. Patients with 10 mm or more of intraoperative liftoff improved from 9.9° tilt preoperatively to 6.6° postoperatively. Patients with no intraoperative liftoff had a change from 6.3° to 2.9°. Although the 2 groups were statistically different, the amount of change in alignment was not different between the groups. Patients with medial patellar liftoff at the time of arthroplasty do not appear to require lateral release to yield acceptable postoperative patellofemoral alignment.

Chondrocyte Death Associated with Human Femoral Osteochondral Harvest as Performed for Mosaicplasty

Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 +/- 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 microm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 +/- 68.2 microm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 +/- 18.8 microm compared with 34.8 +/- 3.2 microm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 +/- 38.9 microm compared with 41.3 +/- 13.4 microm; p = 0.0286). The margin of superficial zone cell death showed no increase during the time-period between fifteen minutes and two hours after plug harvest. A mathematical approximation of the mosaicplasty region suggested that early cell death of this magnitude affects about one third of the superficial graft area. The results of the present study suggest that mosaicplasty, while capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration and articular reconstruction.

CHONDROCYTE DEATH ASSOCIATED WITH HUMAN FEMORAL OSTEOCHONDRAL HARVEST AS PERFORMED FOR MOSAICPLASTY

Background: Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. Methods: Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. Results: The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 ± 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 μm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 ± 68.2 μm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 ± 18.8 μm compared with 34.8 ± 3.2 μm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 ± 38.9 μm compared with 41.3 ± 13.4 μm; p = 0.0286). The margin of superficial zone cell death showed no increase during the time-period between fifteen minutes and two hours after plug harvest. A mathematical approximation of the mosaicplasty region suggested that early cell death of this magnitude affects about one third of the superficial graft area. Conclusions: The results of the present study suggest that mosaicplasty, while capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration and articular reconstruction. Clinical Relevance: The data suggest that there is a need to improve the plug-harvest technique, which may improve graft-recipient healing and clinical outcomes.