Abstract
Background:
There has been increased interest in the biologic augmentation of osteochondral allografts (OCAs), specifically the use of autologous bone marrow, to decrease failure rates. The iliac crest is a common donor site, but its use is associated with increased pain separate from the primary surgical site and increased complexity in the operating room setup and draping. Local bone marrow aspirate (BMA) from the proximal tibia or femoral condyle addresses these limitations, but the quality of the aspirate may be lower. It has not been determined whether this difference in aspirate quality influences the postoperative imaging appearance of OCA grafts.
Purpose:
To determine whether bone marrow aspirate augmentation from the iliac crest versus the proximal tibia affected 6-month postoperative magnetic resonance imaging (MRI) appearance of OCA grafts.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
Patients undergoing OCA transplantation for grade IV chondral defects of the distal femur from January 2018 to June 2021, with 6-month (±2 months) postoperative knee MRI, were included in the study. Patients without knee postoperative MRI, patients with multiple plugs on different surfaces of the knee, and patients with patellar OCA plugs were excluded. Osteochondral Allograft Magnetic Resonance Imaging Scoring System (OCAMRISS) scores were calculated and compared for patients undergoing OCA with either ipsilateral iliac crest BMA augmentation or ipsilateral proximal tibia BMA augmentation.
Results:
Of 56 patients (62 knees) who met the inclusion criteria, 33 had tibial BMA augmentation and 29 had iliac crest BMA augmentation. The mean age was 34.9 ± 10.4 years, the median [IQR] body mass index was 25.5 kg/m2 [23.6-28.3 kg/m2], and the mean time from surgery to MRI was 6.2 ± 0.9 months. Most lesions involved the medial femoral condyle (29 lesions, 47%). The mean OCAMRISS score was 6.9 ± 2.8. There were no differences in the proximal tibia and iliac crest BMA groups with respect to demographic factors, lesion location, or OCAMRISS score on 6-month postoperative MRI (P > .05 for all).
Conclusion:
BMA augmentation does not affect the 6-month postoperative MRI appearance of OCA grafts.
Keywords
Osteochondral allografts (OCAs) are a common treatment option for large, full-thickness chondral defects of the knee. They typically demonstrate favorable mid- and long-term clinical outcomes and high patient satisfaction, yet approximately one-fifth of patients experience early graft failure in pooled meta-analyses. In the literature, failure is defined heterogeneously, including need for revision surgery, conversion to partial or total knee arthroplasty, imaging evidence of structural graft failure, and persistent clinical symptoms.3,7,8,10,17,19,21
OCA healing relies on both osseous and cartilaginous healing into the native tissue. While osseous integration relies on incorporation and remodeling of the subchondral bone by host cells via creeping substitution, the healing of cartilage relies on chondrocyte viability and fibrocartilaginous connections being made between the graft and native tissue.9,13,15 Biologics such as bone marrow aspirate (BMA) and bone marrow aspirate concentrate (BMAC) are thought to potentially expedite or improve integration by providing a high concentration of osteoprogenitor cells and growth factors to facilitate annealing of the allograft articular cartilage to the surrounding host articular cartilage. 6 When determining the optimal location of BMA harvest, there are many potential donor locations, including the iliac crest, proximal tibia, distal femur, and calcaneus, and each location has its unique advantages and disadvantages. The proximal tibia confers the advantage of easy accessibility during knee surgery and location in a safe anatomic area with avoidance of potential complications, such as bowel perforation, and reduced procedural cost due to decreased operative time and the ability to harvest within the same sterile field. 16 Moreover, previous studies have determined that BMA harvest from the proximal tibia is associated with less pain compared with the iliac crest.2,14 However, the proximal tibia has been shown to have fewer progenitor cells compared with the iliac crest. 5 Previous studies evaluating the use of BMA in conjunction with OCAs for cartilage restoration have found mixed results regarding OCA incorporation observed in postoperative imaging.1,12,18,20,22 Oladeji et al 12 found that OCAs soaked with BMAC from the distal femoral metaphysis before implantation had superior bony integration and less sclerosis on magnetic resonance imaging (MRI) at 6 months postoperatively compared with controls. Similarly, Yanke et al 22 showed that patients treated with OCA and BMAC from the iliac crest demonstrated fewer cystic changes than controls. On the other hand, 2 retrospective reviews of patients treated with OCA alone versus OCA with BMAC showed no differences in osseous integration, cystic changes, or other bone, cartilage, and ancillary features as evaluated on MRI.1,20 To date, no studies have evaluated potential differences in OCA graft integration on postoperative MRI following augmentation with BMA from the iliac crest compared with BMA from the proximal tibia. The aim of the present study is to compare the MRI appearance of OCA grafts augmented with iliac crest BMA versus proximal tibia BMA at 6 months postoperatively. We hypothesized that there would be no difference in the MRI appearance of OCA grafts augmented with iliac crest BMA versus proximal tibia BMA.
Methods
Patient Selection
Following institutional review board approval, patients who had undergone OCA transplant for grade IV chondral defects about the distal femur or trochlea by 1 of 2 senior sports medicine fellowship-trained surgeons (S.M.S., A.H.G.) at a single tertiary care institution from January 2018 to June 2021 were identified through review of the electronic medical record. Both surgeons use BMA augmentation for all OCA procedures. One surgeon always harvests from the iliac crest, while the other always harvests from the proximal tibia. All other procedural aspects of the OCA procedure are identical between surgeons, including tissue bank, graft preparation system, and technique. Patients were included in the study if they had a knee MRI performed between 4 and 8 months postoperatively. Patients with multiple plugs placed using the snowman technique were included, and each plug was scored separately. Patients without knee MRI performed between 4 and 8 months postoperatively, patients with multiple plugs on different surfaces of the knee (eg, trochlea and femoral condyle), and those with patellar OCA plugs were excluded from the study.
Surgical Technique
BMA was obtained from either the ipsilateral proximal tibial metaphysis or the ipsilateral iliac crest. The rationale from the senior author (S.M.S.), who uses BMA from the ipsilateral iliac crest, was to strive for the gold standard BMA, with the highest amount of progenitor cells and stem cells. Comparatively, the rationale for the other senior author (A.H.G.) was to obtain BMA from a more easily accessible, less painful, and cost-effective location. For the iliac crest aspiration, 8 to 10 mL of bone marrow was aspirated using the Marrow Cellution trocar system (Ranfac). The anterior superior iliac crest was palpated, and the trocar was inserted approximately 4 cm deep.Then, 1 mL of marrow was aspirated, the trocar was retracted by 1 cm, and the process was repeated for a total of 7 to 8 mL. For the proximal tibial aspiration, a short Jamishidi needle trocar was placed into the proximal medial or lateral tibia, and 4 to 6 mL of bone marrow was aspirated.
For OCA implantation, a standard anterior approach to the knee was performed. A medial or lateral parapatellar arthrotomy was used to access the defect, which was then sized. The defect site was reamed to a depth of 5 to 6 mm. The OCA plug was prepared with a proprietary system (Joint Restoration Foundation), and allogenic bone marrow was reduced with a combination of the pulse lavage and pressurized carbon dioxide using a patented delivery device (CarboJet, Kinamed). The plug was dried, soaked in bone marrow aspirate per standard practice,1,12,20 and placed into the defect with manual pressure. The graft was seated flush with the adjacent cartilage.
Postoperatively, patients were made toe-touch weightbearing for 4 weeks with range of motion as tolerated. Patients were allowed to return to impact sports at 6 months postoperatively.
MRI/Osteochondral Allograft Magnetic Resonance Imaging Scoring System
MRI scans were performed with a 1.5 or 3.0 Tesla magnet. It is our standard practice to obtain MRI scans for all patients undergoing cartilage repair procedures at 6 and 12 months postoperatively to assess the integrity and maturation of the graft to help guide rehabilitation and return to activity. However, due to insurance restraints and patient availability, not all patients are able to obtain imaging.
For this imaging study, we used the previously published and validated Osteochondral Allograft Magnetic Resonance Imaging Scoring System (OCAMRISS).4,11 The original scoring system includes 5 primary cartilage features, 4 primary bone features, and 4 ancillary features, as outlined in Table 1. The integrity of the calcified cartilage layer (item 5) was not included in this study because of the absence of the necessary ultrashort-echo time sequences in our MRI scans. A sports medicine surgeon (G.M.P.) specifically trained by one of the authors of the original OCAMRISS validation 11 study and an orthopaedic surgery resident (T.K.K.) calculated OCAMRISS scores for each graft. Interobserver reliability scores were also calculated to establish reliability in scoring.
MRI, magnetic resonance imaging.
Statistical Analysis
Continuous data were reported as either means and standard deviations or medians and interquartile ranges. Categorical data were reported as frequencies and percentages. Shapiro-Wilk tests were performed to assess for normality of data. Nonnormally distributed data were analyzed with Wilcoxon rank-sum tests, whereas normally distributed data were analyzed with unpaired t tests. Categorical data were analyzed with chi-square tests. Differences in groups were determined using analysis of variance. The intraclass correlation coefficient for the OCAMRISS was calculated using a 2-way mixed-effects model, and OCAMRISS subscores were pooled for simplicity. Statistical significance was determined at P < 0.05. Statistical analysis was performed with STATA (version 17.0; StataCorp).
Results
In total, 56 patients (62 knees) met the inclusion criteria. The mean age was 34.9 ± 10.4 years, the median [IQR] body mass index was 25.5 kg/m2 [23.6-28.3 kg/m2], and the mean time from surgery to MRI was 6.2 ± 0.9 months. There were 33 women, 36 patients with a history of surgery, and 37 patients with 1 or more concomitant procedures included in the study. Of the patients, 33 had tibial bone marrow aspirate, whereas 29 had iliac crest bone marrow aspirate. There were no demographic differences between the tibia and iliac crest groups with respect to age, body mass index, time to MRI, sex, history of surgery, or concomitant procedure performed (P > .05 for all; Table 2).
Demographic Factors for Patients Included in the Study (n = 56) a
Values are reported as mean ± SD, median [IQR], or number (%). Statistical significance at P < .05. BMI, body mass index; MRI, magnetic resonance imaging.
Of the 62 knees included in the study, the median [IQR] plug diameter was 2.0 cm [1.6-2.4 cm]. Most lesions involved the medial femoral condyle (29 lesions, 47%), followed by the trochlea (19 lesions, 31%) and the lateral femoral condyle (14 lesions, 22%). There were no differences between the tibia and iliac crest groups with respect to plug diameter, laterality, or lesion location (P > .05 for all; Table 3).
Lesion Characteristics: Laterality, Plug Location, and Average Plug Diameter for the Knees Included in the Study (n = 62) a
Values are reported as median [IQR] or number (%). Statistical significance at P < .05. LFC, lateral femoral condyle; MFC, medial femoral condyle.
The intraclass correlation coefficient for the OCAMRISS scores was 0.97. The mean OCAMRISS score was 6.9 ± 2.8. There were no differences between the tibia and iliac crest groups with respect to total OCAMRISS score (P = .57) or any of the OCAMRISS subscores (P > .05 for all; Table 4, Figure 1, Figure 2).
Evaluation of Osteochondral Allograft Plugs Using the OCAMRISS a
Statistical significance at P < .05. OCAMRISS, Osteochondral Allograft Magnetic Resonance Imaging Scoring System.

Representative sagittal (left) and coronal (right) magnetic resonance image of osteochondral allograft transplant augmented with bone marrow aspirate from the proximal tibia.

Representative sagittal and coronal magnetic resonance image of osteochondral allograft transplant augmented with bone marrow aspirate from the iliac crest.
Discussion
BMA is commonly added to OCA to provide osteoprogenitor cells and growth factors to possibly aid healing postoperatively, although the optimal source of BMA remains unknown. In this study, we found no difference in the MRI appearance of OCA grafts augmented with BMA harvested from the iliac crest compared with the proximal tibia at 6 months postoperatively.
The effect of biologic augmentation on the postoperative imaging appearance of OCA grafts remains mixed in the literature. Oladeji et al 12 found that OCA grafts treated with BMAC harvested from the iliac crest, distal femoral metaphysis, and proximal tibia metaphysis had improved graft integration and less graft sclerosis compared with OCA grafts without BMAC augmentation on 6-month postoperative plain radiographs. Similarly, Stoker et al 18 compared osseous integration of OCAs with BMAC versus platelet-rich plasma, finding that only the BMAC samples had viable cells on the osseous portion of the allografts compared with OCA without BMAC. By contrast, Wang et al 20 found no difference in osseous integration of OCA grafts augmented with BMAC harvested from the iliac crest compared with OCA grafts without BMAC augmentation on 6-month postoperative MRI. Finally, Ackermann et al 1 evaluated for differences in osseous integration of OCA grafts with and without distal femoral BMA augmentation and similarly found no difference in the imaging appearance of OCA grafts with and without BMA augmentation. Notably, heterogeneity in the location of BMA aspiration, aspirate concentration, aspiration techniques, imaging modalities, patient demographics, and defect locations renders drawing conclusions from the aforementioned cohort studies challenging. The senior authors believe that although there are mixed conclusions on the effects of BMA/BMAC on OCA osseous integration, OCAs should still be soaked with BMA/BMAC for the potential improvements to osseous integration, given minimal complication rates and the gravity of graft failure. However, while the risks of BMAC harvest are quite rare, they have been documented. These negative effects include donor site pain and minor bleeding potential for infection, with more serious concerns being potential nerve damage and hemorrhagic events. Even though these are infrequently seen by the senior authors and were not evaluated in this particular study, it remains important to acknowledge that this procedure is not without risk, and further study on concomitant BMAC harvest is warranted.
There are practical benefits to using BMA from the proximal tibia in place of BMA from the iliac crest. Proximal tibia BMA saves operative time, as this technique forgoes the need to prep and drape a second surgical site. The proximal tibia is also a safer anatomic region from which to obtain bone marrow than the iliac crest and avoids the potential risks of iliac crest harvest, including bowel perforation. 16 However, previous reports have demonstrated lower counts of stem cells in bone marrow aspirations about the knee, with the literature supporting about a 2- to 4-fold higher concentration of mesenchymal stem cells and mononuclear cells in BMAC from the iliac crest compared with the proximal tibia. 5 Reassuringly, our results demonstrate that despite this potential biological limitation of proximal tibial BMA, imaging parameters of integration were no different.
There are several limitations to the present study. First, this study is retrospective in nature and is associated with all limitations typically assigned to retrospective cohort studies. Next, OCAMRISS may not be sensitive enough to detect small but clinically relevant differences in graft integration. 1 Several subscales of OCAMRISS are dichotomous, which limits the identification of the varying degrees of integration at the host-graft junction. Our sample size also limited the ability to control for lesion size, concomitant procedures, patient demographics, or defect location. Another limitation is the lack of blinded randomization, which may be a source of bias in the present study. Additionally, only 2 surgeons were included, which, while decreasing variability in technique, may limit the generalizability of our findings. We also did not quantitatively or qualitatively analyze BMA samples before augmentation, and therefore, we cannot comment on the quality of the aspirate from either location. Furthermore, while there was no difference between iliac crest and proximal tibia BMA, our study was underpowered to detect any true difference in long-term OCA healing. Finally, the fact that the senior surgeons use BMA in all patients does not allow for the determination of the ideal population who may benefit from the use of autograft augmentation to potentially improve healing rates. This is certainly an area for future investigation.
Conclusion
We found no difference in osseous integration between OCAs augmented with autogenous BMA from the proximal tibia compared with autogenous BMA from the iliac crest on 6-month postoperative MRI.
Footnotes
Final revision submitted November 6, 2025; accepted November 9, 2025.
One or more of the authors has declared the following potential conflict of interest or source of funding: S.M.S. is a board or committee member of the Arthroscopy Association of North America; is a reviewer for the American Journal of Sports Medicine; has received consulting fees from Bioventus LLC, Miach Orthopaedics, Moximed, Smith & Nephew, and Vericel; has received hospitality payments from Bioventus LLC, Cartiheal, DePuy Synthes Sales, Joint Restoration Foundation, Linvatec, Miach Orthopaedics, Organogenesis, Pacira Therapeutics, and Smith & Nephew; has received research support from Cartiheal, Hyalex Orthopaedics, Joint Restoration Foundation, Miach Orthopaedics, and Organogenesis; has stock or stock options with Engage, Moximed, Smith & Nephew, and Stryker; has received honoraria from the Joint Restoration Foundation and Vericel; has received travel and lodging from the Joint Restoration Foundation and Smith & Nephew; and has received compensation for services other than consulting, including serving as faculty, as a speaker at a venue other than a continuing education program, or as a speaker for a medical education program from Smith & Nephew and Vericel. A.H.G. is a board or committee member of the Arthroscopy Association of North America and ICRS; has received consulting fees from Bioventus LLC, Cartiheal, Joint Restoration Foundation, Moximed, Organogenesis, Smith & Nephew, and Vericel; has received hospitality payments from Bioventus LLC, Cartiheal, DePuy Synthes Sales, Joint Restoration Foundation, Linvatec, Miach Orthopaedics, Organogenesis, Pacira Therapeutics, and Smith & Nephew; has received research support from Cartiheal, Hyalex Orthopaedics, Joint Restoration Foundation, Miach Orthopaedics, and Smith & Nephew; is on the editorial or governing board of Cartilage, Orthopaedic Journal of Sports Medicine, and Knee Surgery, Sports Traumatology, Arthroscopy; has stock or stock options with Engage, Moximed, and Stryker; has received honoraria from the Joint Restoration Foundation and Vericel; has received travel and lodging from the Joint Restoration Foundation; has royalties or licenses with Organogenesis; has acquisitions with Smith & Nephew; and has received compensation for services other than consulting, including serving as faculty, as a speaker at a venue other than a continuing education program, or as a speaker for a medical education program Linvatec, Pacira Therapeutics, and Vericel.
Ethical approval was obtained from the Hospital for Special Surgery Institutional Review Board. IRB approved, #2020-2123.
