Diaphyseal Impaction Grafting Combined with Metaphyseal Cones: Outcomes in 88 Revision Total Knee Arthroplasties.

BACKGROUND: Metaphyseal cones with cemented stems can be successfully utilized in most revision total knee arthroplasties (TKAs). However, if the diaphysis has been previously violated, fixation of the cemented stem, which is important for cone ingrowth and construct survival, can be compromised. The initial results of our novel technique combining diaphyseal impaction bone-grafting with a metaphyseal cone were promising but required additional study. The purpose of the present study was to assess results of this technique in a larger cohort. METHODS: A metaphyseal cone combined with diaphyseal impaction grafting and a cemented stem was utilized in 88 revision TKAs at our institution, including 35 from our prior study. The mean age at the time of revision was 67 years, and 67% of patients were male. Patients had had a mean of 4 prior knee arthroplasty procedures. The 2 most common reasons for revision were aseptic loosening (78%) and 2-stage reimplantation for periprosthetic joint infection (PJI) (19%). The mean follow-up was 4 years. RESULTS: At the time of the latest follow-up, no cone-impaction grafting constructs required re-revision for aseptic loosening. Five-year survivorship free from any revision of the cone-impaction grafting construct and free from any reoperation was 95% and 65%, respectively. A total of 25 knees (28%) underwent reoperation, with the 2 most common indications being PJI and periprosthetic fracture. All cones were osseointegrated, and all bone graft appeared stable or incorporated. One patient had radiographic evidence of tibial component loosening despite a well-fixed cone; however, this patient was asymptomatic and had not undergone revision at 9 years. CONCLUSIONS: When presented with a sclerotic, polished diaphyseal canal with deficient cancellous bone and concomitant metaphyseal bone loss, our technique of combining diaphyseal impaction grafting with a metaphyseal cone proved extremely durable in this larger series of patients. No cone-impaction grafting constructs required re-revision for aseptic loosening. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Contemporary outcomes of primary total hip arthroplasty in patients with inflammatory arthritis.

Aims: Contemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis. Methods: We identified 418 hips (350 patients) with a primary diagnosis of inflammatory arthritis who underwent primary THA with HXLPE liners from January 2000 to December 2017. Of these hips, 68% had rheumatoid arthritis (n = 286), 13% ankylosing spondylitis (n = 53), 7% juvenile rheumatoid arthritis (n = 29), 6% psoriatic arthritis (n = 24), 5% systemic lupus erythematosus (n = 23), and 1% scleroderma (n = 3). Mean age was 58 years (SD 14.8), 66.3% were female (n = 277), and mean BMI was 29 kg/m2 (SD 7). Uncemented femoral components were used in 77% of cases (n = 320). Uncemented acetabular components were used in all patients. Competing risk analysis was used accounting for death. Mean follow-up was 4.5 years (2 to 18). Results: The ten-year cumulative incidence of any revision was 3%, and was highest in psoriatic arthritis patients (16%). The most common indications for the 15 revisions were dislocations (n = 8) and periprosthetic joint infections (PJI; n = 4, all on disease-modifying antirheumatic drugs (DMARDs)). The ten-year cumulative incidence of reoperation was 6.1%, with the most common indications being wound infections (six cases, four on DMARDs) and postoperative periprosthetic femur fractures (two cases, both uncemented femoral components). The ten-year cumulative incidence of complications not requiring reoperation was 13.1%, with the most common being intraoperative periprosthetic femur fracture (15 cases, 14 uncemented femoral components; p = 0.13). Radiological evidence of early femoral component subsidence was observed in six cases (all uncemented). Only one femoral component ultimately developed aseptic loosening. Harris Hip Scores substantially improved (p < 0.001). Conclusion: Contemporary primary THAs with HXLPE in patients with inflammatory arthritis had excellent survivorship and good functional outcomes regardless of fixation method. Dislocation, PJI, and periprosthetic fracture were the most common complications in this cohort with inflammatory arthritis.

Intraoperative Dysrhythmias Cease After Venting During Intramedullary Nailing of an Impending Femur Fracture: A Case Report.

CASE: A 76-year-old woman with multiple myeloma and osteoporosis presented with right hip pain and an impending atypical femoral fracture in the setting of chronic bisphosphonate use. After preoperative medical optimization, she was scheduled for prophylactic intramedullary nail fixation. Intraoperatively, the patient experienced episodes of severe bradycardia and asystole associated with intramedullary reaming, which ceased after distal venting of the femur. No additional intraoperative or postoperative complications were encountered, and the patient recovered uneventfully. CONCLUSION: Femoral canal venting may be an appropriate intervention for similar transient dysrhythmias caused by intramedullary reaming.

The Association Between Preoperative International Normalized Ratio Values and Postoperative Outcomes including Mortality in Geriatric Femoral Neck Fractures Treated With Hemiarthroplasty.

OBJECTIVES: To evaluate the association between preoperative international normalized ratio (INR) and postoperative mortality and other outcomes after hemiarthroplasty for geriatric femoral neck fractures. DESIGN: Retrospective cohort study. SETTING: A single Level-I trauma center. PATIENTS/PARTICIPANTS: Patients ≥55 years of age with OTA/AO 31B proximal femur fractures [1556 patients (1616 hips)]. INTERVENTION: Hip hemiarthroplasty. MAIN OUTCOME MEASUREMENTS: Ninety-day mortality, postoperative transfusion within 72 hours, and 90-day postoperative outcomes. RESULTS: Adjusting for confounders, the association of preoperative INR and 90-day mortality was not statistically significant [hazard ratio (HR): 1.3; 95% confidence interval (CI): 0.97, 1.8; P = 0.08]. Dementia (HR: 1.9; 95% CI: 1.4-2.6; P < 0.001), Charlson Comorbidity Index (HR: 1.1; 95% CI: 1.1-1.2; P < 0.001), and age by decade (HR: 1.4; 95% CI: 1.1-1.8; P = 0.002) were associated with 90-day mortality. Increasing INR was significantly associated with blood transfusion [odds ratio (OR) 1.4; 95% CI 1.03-1.6; P = 0.031]. Preoperative hemoglobin <10 g/dL (OR 13.7; 95% CI 8.4-23.3; P < 0.001) was also associated with a postoperative transfusion, whereas intraoperative tranexamic acid use (OR 0.3; 95% CI 0.2-0.5; P < 0.001) was inversely associated with postoperative transfusion rate. INR was associated with superficial wound infection (HR: 2.0; 95% CI: 1.1-3.7; P = 0.02) and noninfected wound complications (HR: 1.6; 95% CI: 1.1-2.4; P = 0.007). Risk of superficial infection increased when INR was >1.8. CONCLUSION: When controlling for confounders, preoperative INR was not significantly associated with 90-day mortality. Underlying medical conditions contribute to postoperative mortality more than an elevated INR. However, INR is associated with superficial wound complications. This risk becomes statistically significant as INR rises above 1.8. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Recent Antibiotic Treatment Impacts Serum and Synovial Laboratory Values in Early Periprosthetic Joint Infection Workup.

BACKGROUND: Accurately detecting early postoperative periprosthetic joint infection (PJI) following total hip arthroplasty (THA) and total knee arthroplasty (TKA) remains challenging. The purpose of our study was to determine the impact of antibiotics given prior to laboratory evaluation on the reliability of serologic and synovial fluid tests to identify PJI in the early postoperative period. METHODS: We identified 49,861 primary total hip arthroplasties and total knee arthroplasties performed between 2000 and 2019. Among these patients, 21 hips and 28 knees that underwent arthrocentesis within 12 weeks of their arthroplasty were identified as infected. Patients who had received antibiotics within 2 weeks prior to laboratory evaluation were compared to those who had not. Median values of C-reactive protein, erythrocyte sedimentation rate, synovial white blood cell (WBC) count, synovial neutrophil percentage, and synovial absolute neutrophil count were compared between groups. The false negative rate for detecting PJI using laboratory values was compared using published cutoffs for PJI in the early postoperative period. RESULTS: Median values of C-reactive protein (105 vs 22 mg/L; P = .006), synovial WBC count (57,591 vs 4,473 cells/µL; P = .003), synovial neutrophil percentage (94% vs 76%; P = .004), and synovial absolute neutrophil count (50,748 vs 2,804 cells/µL; P < .001) were significantly lower in patients who received antibiotics compared to those who did not. False negative rates for detecting PJI were significantly higher for synovial WBC and synovial neutrophil percentage in patients treated with antibiotics compared to untreated patients. CONCLUSION: False negative rates for detecting early PJI when using published cutoffs were markedly higher in antibiotic-treated patients compared to untreated patients for synovial WBC count and synovial neutrophil percentage. LEVEL OF EVIDENCE: Level IV retrospective review.

Laboratory Value Effectiveness in Predicting Early Postoperative Periprosthetic Joint Infection After Total Hip Arthroplasty.

BACKGROUND: Diagnosing early periprosthetic joint infection (PJI) after primary total hip arthroplasty (THA) remains challenging. We sought to validate optimal laboratory value cutoffs for detecting early PJIs in a series of primary THAs from one institution. METHODS: We retrospectively identified 22,795 primary THAs performed between 2000 and 2019. Within 12 weeks, 43 hips (43 patients) underwent arthrocentesis. Patients were divided into 2 groups: evaluation ≤6 weeks or 6-12 weeks following THA. The 2011 Musculoskeletal Infection Society major criteria for PJI diagnosed PJI in 15 patients. Mann-Whitney U-tests were used to compare median laboratory values and receiver operating characteristic curve analysis was used to evaluate optimal cutoff values. RESULTS: Both within 6 weeks and between 6 and 12 weeks postoperatively, median C-reactive protein (CRP), erythrocyte sedimentation rate, synovial white blood cell (WBC) count, neutrophil percentage, and absolute neutrophil count (ANC) values were significantly higher in infected THAs. Optimal cutoffs within 6 weeks were: CRP ≥100 mg/L, synovial WBCs ≥4390 cells/µL, neutrophil percentage ≥74%, and ANC ≥3249 cells/µL. Between 6 and 12 weeks, optimal cutoffs were: CRP ≥33 mg/L, synovial WBCs ≥26,995 cells/µL, neutrophil percentage ≥93%, and ANC ≥25,645 cells/µL. CONCLUSION: Early PJI following THA should be suspected within 6 weeks with CRP ≥100 mg/L or synovial WBCs ≥4390 cells/µL. Between 6 and 12 weeks postoperatively, cutoffs of CRP ≥33 mg/L, synovial fluid WBC ≥26,995 cells/µL, and neutrophil percentage ≥93% diagnosed PJI with high accuracy. LEVEL OF EVIDENCE: Level IV Diagnostic.

Factors Associated With Early Return to Driving Following Total Joint Arthroplasty.

BACKGROUND: Patients often ask when they can safely return to driving a car following total joint arthroplasty (TJA). Most prior research has relied on driving simulators. Our study sought to learn more about real-world patient experiences in returning to driving after total knee arthroplasty (TKA) or total hip arthroplasty (THA). METHODS: Our institutional total joint registry was used to identify living patients aged 18-85 who underwent primary TKA or primary THA for a primary diagnosis of osteoarthritis between January 1, 2019 and December 31, 2019. Patients who had undergone multiple TJA operations in 2019 or had a primary mailing address outside of the United States were excluded. Ultimately 2508 eligible TJA patients received a survey by mail. RESULTS: A total of 1128 of 2508 eligible patients (45%) completed surveys and returned them by mail. After 121 surveys were discarded for incompletion, inconsistency, or limited preoperative driving volume, 1007 patients were included in our study. Among these patients, 99% returned to driving postoperatively, with 23% returning within 2 weeks, and 88% returning within 6 weeks. Factors associated with the odds of a patient returning to driving within 2 weeks included laterality, gender, postoperative confidence, postoperative comfort, and surgeon advice. Ten patients (1%) have been involved in a car accident postoperatively. CONCLUSION: Almost all patients returned to driving postoperatively without being involved in a car accident. Gender, laterality, patient confidence, and comfort as well as surgeon advice were significantly associated with the odds of a patient returning to driving within 2 weeks postoperatively.

The effectiveness of laboratory tests to predict early postoperative periprosthetic infection after total knee arthroplasty.

AIMS: It remains difficult to diagnose early postoperative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). We aimed to validate the optimal cutoff values of ESR, CRP, and synovial fluid analysis for detecting early postoperative PJI in a large series of primary TKAs. METHODS: We retrospectively identified 27,066 primary TKAs performed between 2000 and 2019. Within 12 weeks, 169 patients (170 TKAs) had an aspiration. The patients were divided into two groups: those evaluated ≤ six weeks, or between six and 12 weeks postoperatively. The 2011 Musculoskeletal Infection Society (MSIS) criteria for PJI diagnosis in 22 TKAs. The mean follow-up was five years (two months to 17 years). The results were compared using medians and Mann-Whitney U tests and thresholds were analyzed using receiver operator characteristic curves. RESULTS: Within six weeks, the median CRP (101 mg/l vs 35 mg/l; p = 0.011), synovial WBCs (58,295 cells/µl vs 2,121 cells/µl; p ≤ 0.001), percentage of synovial neutrophils (91% vs 71% (p < 0.001), and absolute synovial neutrophil count (ANC) (50,748 cells/µl vs 1,386 cells/µl (p < 0.001) were significantly higher in infected TKAs. Between six and 12 weeks, the median CRP (85 mg/l vs 5 mg/l (p < 0.001)), ESR (33 mm/hr vs 14 mm/hr (p = 0.015)), synovial WBCs (62,247 cells/µl vs 620 cells/µl (p < 0.001)), percentage of synovial neutrophils (93% vs 54% (p < 0.001)), and ANC (55,911 cells/µl vs 326 cells/µl (p < 0.001)) were also significantly higher in infected TKAs. Optimal thresholds at ≤ six weeks were: CRP ≥ 82 mg/l (sensitivity 70%, specificity 77%), synovial WBCs ≥ 8,676 cells/µl (83%, 90%), percentage of synovial neutrophils ≥ 88% (67%, 78%), and ANC ≥ 8,346 cells/µl (83%, 91%). Between six and 12 weeks, thresholds were: CRP ≥ 34 mg/l (90%, 93%), synovial WBCs ≥ 1,983 cells/µl (80%, 85%), percentage of synovial neutrophils ≥ 76% (80%, 81%), and ANC ≥ 1,684 cells/µl (80%, 87%). CONCLUSION: Early PJI after TKA should be suspected within six weeks if the CRP is ≥ 82 mg/l, synovial WBCs are ≥ 8,676 cells/µl, the percentage of synovial neutrophils is ≥ 88%, and/or the ANC is ≥ 8,346 cells/µl. Between six and 12 weeks, thresholds include a CRP of ≥ 34 mg/l, synovial WBC of ≥ 1,983 cells/µl, a percentage of synovial neutrophils of ≥ 76%, and/or an ANC of ≥ 1,684 cells/µl. Cite this article: Bone Joint J 2021;103-B(6 Supple A):177-184.

Bias Does Not Exist in Treating Knee Periprosthetic Joint Infection Among Patients With Substance Use Disorder.

Debridement, antibiotics with implant retention (DAIR), and 2-stage revision are standard surgical interventions for treating knee periprosthetic joint infection (PJI). Patients with substance use disorder (SUD), especially addictive drug use disorder (DUD), have been shown to receive inferior medical care in many specialties compared with nonusers. The authors identified patients with a diagnosis of PJI after knee arthroplasty who received either DAIR or 2-stage revision with the Nationwide Inpatient Sample (NIS) database from 2010 to 2014. Patients were stratified into 2 groups, patients with DUD and nonusers, based on Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. Descriptive analysis was conducted to show the national trend for knee PJI treatment among the 2 patient groups. Multivariate logistic regression was used to compare the prevalence of DAIR and 2-stage revision between these 2 groups, adjusted for likely confounders, including age, sex, income, race, and comorbidities. Among the 11,331 patients with knee infection, 139 (1.23%) had DUD. Compared with nonusers, patients with DUD were significantly younger (P<.001), had more chronic conditions (P<.001), and were predominantly in lower income quartiles (P=.046). The 2 groups did not differ in sex and race (P=.072 and P=.091, respectively). The authors found that 30.22% of patients with DUD and 36.36% of nonusers received DAIR. The difference in these proportions was not statistically significant (P=.135). The results did not change after adjustment for confounding factors (P=.509). The findings suggested that bias does not exist among orthopedic surgeons who choose DAIR or 2-stage revision for knee PJI among patients with DUD. [Orthopedics. 2021;44(3):e385-e389.].

Comparing Inpatient Complication Rates between Octogenarians and Nonagenarians Following Primary and Revision Total Hip Arthroplasty in a Nationally Representative Sample 2010-2014.

We compared inpatient postoperative complication rates between octogenarians and nonagenarians undergoing primary and revision total hip arthroplasty (THA). We used inpatient admission data from 2010-2014 from the Nationwide Inpatient Sample (NIS). We compared the rates at which nonagenarians and octogenarians developed each complication in the inpatient setting following both primary THA (PTHA) and revision THA (RTHA). A total of 40,944 inpatient admissions were included in our study which extrapolates to a national estimate of 199,793 patients. A total of 185,799 (93%) were octogenarians and 13,994 (7%) were nonagenarians. PTHA was performed on 155,669 (78%) and RTHA was performed on 44,124 (22%) of the patients. Nonagenarians undergoing PTHA required transfusions significantly more frequently (33.13% v. 24.0%, p < 0.001) and developed urinary tract infection (5.14% v. 3.92%, p = 0.012) and acute kidney injury (5.50% v. 3.57%, p < 0.001) significantly more frequently than octogenarians. Nonagenarians undergoing RTHA required transfusions significantly more frequently (51.43% v. 41.46%, p < 0.001) and developed urinary tract infection (19.66% v. 11.73%, p < 0.001), acute kidney injury (13.8% v. 9.66%, p < 0.001), pulmonary embolism (1.24% v. 0.67%, p = 0.031), postoperative infection (1.89% v. 1.11%, p = 0.023), sepsis (3.59% v. 2.43%, p = 0.021) and other postoperative shock (1.76% v. 1.06%, p = 0.036) significantly more frequently than octogenarians. Nonagenarians undergoing RTHA also had a significantly higher inpatient mortality rate (3.28% v. 1.43%, p < 0.001) than octogenarians. Orthopedic surgeons and primary care providers can use these findings to help counsel both their octogenarian and nonagenarian patients preoperatively when considering THA. Our analysis can help these patients better understand expected inpatient complication rates and assist them in deciding whether to pursue surgical intervention when applicable.

Comparing Inpatient Complication Rates between Octogenarians and Nonagenarians following Primary and Revision Total Knee Arthroplasty in a Nationally Representative Sample, 2010⁻2014.

We compared the inpatient postoperative complication rates between octogenarians and nonagenarians undergoing primary and revision total knee arthroplasty (TKA). We used the Nationwide Inpatient Sample (NIS) to analyze inpatient admission data from 2010⁻2014. We compared the rates at which nonagenarians and octogenarians developed each complication following both primary TKA (PTKA) and revision TKA (RTKA). A national estimate of 324,933 patients were included in our study. A total of 313,299 (96.42%) were octogenarians, and 11,634 (3.58%) were nonagenarians. 294,462 (90.62%) underwent PTKA, and 30,471 (9.38%) underwent RTKA. Nonagenarians undergoing PTKA had a higher inpatient mortality rate, and developed sepsis more frequently than octogenarians. Nonagenarians undergoing RTKA had a higher inpatient mortality rate, and developed cardiogenic shock more frequently than octogenarians. In both PTKA and RTKA, nonagenarians received transfusions more frequently, and developed urinary tract infection and acute kidney injury more frequently than octogenarians. In both PTKA and RTKA, nonagenarians sustained a higher inpatient mortality rate than octogenarians. Orthopedic surgeons should counsel nonagenarian patients undergoing both PTKA and RTKA preoperatively about this increased mortality risk, as well as the increased risks of more minor complications like transfusion, urinary tract infection, and acute kidney injury.

The positive effects of different platelet-rich plasma methods on human muscle, bone, and tendon cells.

BACKGROUND: Clinical application of platelet-rich plasma (PRP) in the realm of orthopaedic sports medicine has yielded variable results. Differences in separation methods and variability of the individual may contribute to these variable results. PURPOSE: To compare the effects of different PRP separation methods on human bone, muscle, and tendon cells in an in vitro model. STUDY DESIGN: Controlled laboratory study. METHODS: Blood collected from 8 participants (mean ± SD age 31.6 ± 10.9 years) was used to obtain PRP preparations. Three different PRP separation methods were used: a single-spin process yielding a lower platelet concentration (PRP(LP)), a single-spin process yielding high platelet and white blood cell concentrations (PRP(HP)), and a double-spin that produces a higher platelet concentration and lower white blood cell concentration (PRP(DS)). Human bone, muscle, and tendon cells obtained from discarded tissue samples during shoulder surgery were placed into culture and treated with the 3 PRP preparations, control media (2% fetal bovine serum [FBS] and 10% FBS), and native blood. Radioactive thymidine assays were obtained to examine cell proliferation, and testing with enzyme-linked immunosorbent assay was used to determine growth factor concentrations. RESULTS: Addition of PRP(LP) to osteocytes, myocytes, and tenocytes significantly increased cell proliferation (P ≤ .05) compared with the controls. Adding PRP(DS) to osteoblasts and tenocytes increased cell proliferation significantly (P ≤ .05), but no significance was shown for its addition to myocytes. The addition of PRP(HP) significantly increased cell proliferation compared with the controls only when added to tenocytes (P ≤ .05). Osteoblasts: Proliferation was significantly increased by addition of PRP(LP) compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRP(DS) led to significantly increased proliferation compared with all controls, native blood, and PRP(HP) (P ≤ .05). Proliferation was significantly less when PRP(HP) was added compared with PRP(DS) (P ≤ .05). Myocytes: Proliferation was significantly increased by addition of PRP(LP) compared with native blood (P ≤ .05). Adding PRP(HP) or PRP(DS) to myocytes showed no significant increase in proliferation compared with the controls or the other separations. Tenocytes: Proliferation was significantly increased by addition of PRP(LP) compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRP(DS) showed a significant increase compared with the controls and native blood. For tenocytes, there was a significant increase (P ≤ .05) seen when PRP(HP) was added compared with the controls and native blood but not compared with the other separations. CONCLUSION: The primary findings of this study suggest the application of different PRP separations may result in a potential beneficial effect on the clinically relevant target cells in vitro. However, it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types. In addition, a "more is better" theory for the use of higher platelet concentrations cannot be supported. This study was not intended to prove efficacy but to provide a platform for future research to be built upon. CLINICAL RELEVANCE: The utilization of different PRP separations may result in a potentially beneficial effect on the clinically relevant target cells in vitro, but it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types.

Rapid isolation of human stem cells (connective progenitor cells) from the distal femur during arthroscopic knee surgery.

PURPOSE: (1) To safely obtain bone marrow aspirates from the distal femur during arthroscopic knee surgery, (2) to purify and efficiently concentrate connective tissue progenitor cells (CTPs) in the operating room (OR), and (3) to confirm that these are CTPs through their ability to differentiate into bone cells. METHODS: Bone marrow aspirates were harvested from the distal femur during arthroscopic knee surgery in 26 patients. Twenty-five matched control subjects were selected to evaluate for increased incidence of complications. CTPs were isolated using a rapid method designed for use in the OR compared with 2 accepted methods. Cytochemical and molecular analysis was used to assess osteogenic potential. RESULTS: Osteogenic potential of the CTPs was confirmed by reverse transcription polymerase chain reaction analysis and cellular staining. Bone marrow was successfully aspirated in 25 cases, with 3 incidences of stiffness in the aspirate group compared with 2 in the control group, 1 incidence of a wound irregularity in the aspirate group compared with 1 in the control group, and 3 incidences of hemarthrosis/persistent effusion in the aspirate group compared with 1 in the control group. The rate of complications for the aspirate group was 36% compared with 25% in the control group. CONCLUSIONS: Our intention was to develop a technique for extracting and purifying bone marrow so that the orthopaedic surgeon would have a simple, safe, and efficient process by which to isolate CTPs during arthroscopic knee surgery. This method of aspiration did not lead to a significant increase in complications. Further bone marrow aspirate was successfully purified in the OR, with only a slight increase in surgery time, and resulted in a fractionated layer rich with CTPs. These cells showed osteogenic potential, as evidenced by their osteoblastic differentiation. These CTPs may have future use in enhancing the incorporation of the graft into the bone. LEVEL OF EVIDENCE: Level III, matched case-control study.