Clinical and MRI Outcomes of Fresh Osteochondral Allograft Transplantation After Failed Cartilage Repair Surgery in the Knee

Subchondral Bone Alignment in Osteochondral Allograft Transplants for Large Oval Defects of the Medial Femoral Condyle: Comparison of Lateral versus Medial Femoral Condyle Donors

OBJECTIVE

Supply-demand mismatch of medial femoral condyle (MFC) osteochondral allografts (OCAs) remains a rate-limiting factor in the treatment of osteochondral defects of the femoral condyle. Surface contour mapping was used to determine whether a contralateral lateral femoral condyle (LFC) versus ipsilateral MFC OCA differs in the alignment of donor:native subchondral bone for large osteochondral defects of the MFC.

DESIGN

Thirty fresh-frozen human femoral condyles were matched by tibial width into 10 groups of 3 condyles (MFC recipient, MFC donor, and LFC donor) each for 3 cartilage surgeons (90 condyles). The recipient MFC was imaged using nano-computed tomography scan. Donor oval grafts were harvested from each matched condyle and transplanted into a 17 mm × 36 mm defect created in the recipient condyle. Following the first transplant, the recipient condyle was imaged and superimposed on the native condyle nano-CT scan. The donor plug was removed and the process repeated for the other donor. Surface height deviation and circumferential step-off height deviation were compared between native and donor subchondral bone surfaces for each transplant.

RESULTS

There was no statistically significant difference in mean subchondral bone surface deviation (LFC = 0.87 mm, MFC = 0.76 mm, P = 0.07) nor circumferential step-off height (LFC = 0.93 mm, MFC = 0.85 mm, P = 0.09) between the LFC and MFC plugs. There were no significant differences in outcomes between surgeons.

CONCLUSIONS

There were no significant differences in subchondral bone circumferential step-off or surface deviation between ipsilateral MFC and contralateral LFC oval-shaped OCAs for 17 mm × 36 mm defects of the MFC.

High-Speed Centrifugation Efficiently Removes Immunogenic Elements in Osteochondral Allografts

OBJECTIVES

The current clinical pulse lavage technique for flushing fresh osteochondral allografts (OCAs) to remove immunogenic elements from the subchondral bone is ineffective. This study aimed to identify the optimal method for removing immunogenic elements from OCAs.

METHODS

We examined five methods for the physical removal of immunogenic elements from OCAs from the femoral condyle of porcine knees. We distributed the OCAs randomly into the following seven groups: (1) control, (2) saline, (3) ultrasound, (4) vortex vibration (VV), (5) low-pulse lavage (LPL), (6) high-pulse lavage (HPL), and (7) high-speed centrifugation (HSC). OCAs were evaluated using weight measurement, micro-computed tomography (micro-CT), macroscopic and histological evaluation, DNA quantification, and chondrocyte activity testing. Additionally, the subchondral bone was zoned to assess the bone marrow and nucleated cell contents. One-way ANOVA and paired two-tailed Student's t-test are used for statistical analysis.

RESULTS

Histological evaluation and DNA quantification showed no significant reduction in marrow elements compared to the control group after the OCAs were treated with saline, ultrasound, or VV treatments; however, there was a significant reduction in marrow elements after LPL, HPL, and HSC treatments. Furthermore, HSC more effectively reduced the marrow elements of OCAs in the middle and deep zones compared with LPL (p < 0.0001) and HPL (p < 0.0001). Macroscopic evaluation revealed a significant reduction in blood, lipid, and marrow elements in the subchondral bone after HSC. Micro-CT, histological analyses, and chondrocyte viability results showed that HSC did not damage the subchondral bone and cartilage; however, LPL and HPL may damage the subchondral bone.

CONCLUSION

HSC may play an important role in decreasing immunogenicity and therefore potentially increasing the success of OCA transplantation.

Increased Host Bone Marrow Edema on 6-Month MRI Is a Risk Factor for Osteochondral Allograft Failure

PURPOSE

To evaluate the presence of host bone marrow edema (BME) surrounding osteochondral allograft (OCA) plugs on routine 6-month postoperative magnetic resonance imaging (MRI) and to determine whether such BME is correlated with subsequent failure.

METHODS

The present study was approved under our institutional review board-approved database (#2020-2123). We included patients who underwent cartilage repair with OCA for focal chondral and osteochondral defects of the distal femur by 2 senior surgeons between January 2016 and May 2021 with minimum 2-year follow-up. OCA is frequently performed with concomitant procedures, and therefore ligament reconstruction, meniscal surgery, and osteotomy were not exclusion criteria. Failure was defined as (1) poor clinical outcome with graft collapse on follow-up MRI or second-look arthroscopy, (2) primary OCA removal or revision, or (3) conversion to unicompartmental or total knee arthroplasty. Routine MRI scans were performed at 6 ± 2 months postoperatively. All postoperative MRI scans were reviewed from our imaging record by 2 blinded fellowship-trained orthopaedic surgeons. Patients were divided for analyses into 2 groups: BME ≥10 cm3 versus BME <10 cm3.

RESULTS

Of the 85 patients eligible for the study, 56 patients (30 female, mean age 31.69 ± 11.34 years) had a minimum 2-year follow-up. Nonfailure cases had a mean clinical follow-up of 3.13 ± 0.93 years. The mean time from surgery to failure in our cohort was 1.67 ± 0.91 years. There were 12 (21.4%) patients with BME ≥10 cm³ and 44 (78.6%) patients with BME <10 cm³. No statistically significant differences were found between groups when compared for sex, age, body mass index, OCA size, time to MRI, mean follow-up, number of plugs, graft location, diagnosis, previous surgeries, or concomitant procedures. All OCA failures of the study cohort were in the BME ≥10 cm³ group, representing 50% of this group (P < .001). Kaplan-Meier survival analysis with the log-rank test demonstrated significant difference in survival distributions between groups (P < .001). Patients who ultimately failed had a mean BME volume of 18.49 ± 5.82 cm3, while the nonfailure group had a mean volume of 4.66 ± 4.97 cm3 (P < .001). Cutoff values around 10 cm³ in receiver operating characteristic curve analysis demonstrated 100% sensitivity and close to 90% specificity for OCA failure diagnosis.

CONCLUSION

Host BME with a volume greater than 10 cm³ on 6-month postoperative MRI is predictive of an increased subsequent failure rate after OCA transplantation with a failure rate of 50%.

LEVEL OF EVIDENCE

Level III, cohort study.

Characteristics and Clinical Outcomes After Osteochondral Allograft Transplantation for Treating Articular Cartilage Defects: Systematic Review and Single-Arm Meta-analysis of Studies From 2001 to 2020

Background

Osteochondral allograft transplantation (OCA) treats symptomatic focal cartilage defects with satisfactory clinical results.

Purpose

To comprehensively analyze the characteristics and clinical outcomes of OCA for treating articular cartilage defects.

Study Design

Systematic review; Level of evidence, 4.

Methods

We searched Embase, PubMed, Cochrane Database, and Web of Science for studies published between January 1, 2001, and December 31, 2020, on OCA for treating articular cartilage defects. Publication information, patient data, osteochondral allograft storage details, and clinical outcomes were extracted to conduct a comprehensive summative analysis.

Results

In total, 105 studies involving 5952 patients were included. The annual reported number of patients treated with OCA increased from 69 in 2001 to 1065 in 2020, peaking at 1504 cases in 2018. Most studies (90.1%) were performed in the United States. The mean age at surgery was 34.2 years, and 60.8% of patients were male and had a mean body mass index of 26.7 kg/m2. The mean lesion area was 5.05 cm2, the mean follow-up duration was 54.39 months, the mean graft size was 6.85 cm2, and the number of grafts per patient was 54.7. The failure rate after OCA was 18.8%, and 83.1% of patients reported satisfactory results. Allograft survival rates at 2, 5, 10, 15, 20, and 25 years were 94%, 87.9%, 80%, 73%, 55%, and 59.4%, respectively. OCA was mainly performed on the knee (88.9%). The most common diagnosis in the knee was osteochondritis dissecans (37.9%), and the most common defect location was the medial femoral condyle (52%). The most common concomitant procedures were high tibial osteotomy (28.4%) and meniscal allograft transplantation (24.7%). After OCA failure, 54.7% of patients underwent revision with primary total knee arthroplasty.

Conclusion

The annual reported number of patients who underwent OCA showed a significant upward trend, especially from 2016 to 2020. Patients receiving OCA were predominantly young male adults with a high body mass index. OCA was more established for knee cartilage than an injury at other sites, and its best indication was osteochondritis dissecans. This analysis demonstrated satisfactory long-term postoperative outcomes.

Surgical Management of Failed Articular Cartilage Surgery in the Knee

Failure rates of cartilage restoration surgery range from 14% to 43%. When failure of prior cartilage restoration surgery is suspected, a thorough clinical workup should be performed to assess the timing and duration of symptoms. Attention should be paid to patient risk factors such as age, body mass index, and smoking status. Concomitant pathology such as malalignment, ligament insufficiency, and meniscus status must be evaluated before revision surgery. As outlined in our treatment algorithm, the size/location of the lesion and the type of primary procedure will guide planning for revision procedures. [Orthopedics. 2023;46(5):262-272.].

Osteochondral Allografts for Large Oval Defects of the Medial Femoral Condyle: A Comparison of Single Lateral Versus Medial Femoral Condyle Oval Grafts Versus 2 Overlapping Circular Grafts

BACKGROUND

Studies have demonstrated the acceptability of using a contralateral nonorthotopic lateral femoral condyle (LFC) graft for a circular medial femoral condyle (MFC) osteochondral defect up to 20 to 25 mm in diameter. Larger oblong defects can now be managed using either overlapping circle grafts or a single oblong-shaped osteochondral allograft (OCA).

PURPOSE

To determine if an oblong contralateral nonorthotopic LFC OCA can attain an acceptable surface contour match compared with an oblong ipsilateral MFC OCA or an overlapping circle technique for large oblong defects of the MFC.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 120 fresh-frozen human femoral condyles were matched by tibial width into 30 groups of 4 condyles (1 recipient MFC, 3 donor condyles). The recipient MFC was initially imaged using nano-computed tomography (nano-CT). A 17 × 36-mm oblong defect was created in the recipient MFC. Overall, 3 donor groups were formed: MFC oblong, LFC nonorthotopic oblong, LFC or MFC overlapping circles. After each transplant, the recipient condyle underwent nano-CT and was digitally reconstructed, which was superimposed on the initial nano-CT scan of the native recipient condyle. Dragonfly 3D software was used to determine the root mean square (RMS) of both the surface height deviation and the circumferential step-off height deviation between the native and donor cartilage surfaces for each graft.

RESULTS

RMS surface height deviations were as follows: 0.59 mm for MFC oblong grafts, 0.58 mm for LFC oblong grafts, and 0.78 mm for overlapping circle grafts. The MFC and LFC oblong grafts had significantly less surface height deviation than the overlapping circle grafts (P = .004 and P = .002, respectively). RMS step-off height deviations were as follows: 0.68 mm for MFC oblong grafts, 0.70 mm for LFC oblong grafts, and 0.85 mm for overlapping circle grafts. The MFC and LFC oblong grafts had significantly less step-off height deviation than the overlapping circle grafts (P < .001 and P = .002, respectively). The majority of this difference was on the medial segment of the overlapping circle grafts.

CONCLUSION

Oblong ipsilateral MFC OCAs and oblong contralateral nonorthotopic LFC OCAs produced a significantly better surface contour match to the native MFC than overlapping circle grafts for oblong defects 17 × 36 mm in size.

CLINICAL RELEVANCE

Size-matched contralateral nonorthotopic LFC grafts are acceptable for MFC defects, which may allow for a quicker match, earlier patient care, and less wastage of valuable donor tissue.

Early Postoperative CT Scan Provides Prognostic Data on Clinical Outcomes of Fresh Osteochondral Transplantation of the Knee

BACKGROUND

There is a lack of information regarding the ability of imaging studies to predict clinical outcomes after fresh osteochondral allograft (FOCA) transplantation of the knee.

PURPOSE

To determine the value of computed tomography (CT) scans to predict the clinical outcome of FOCA transplantation using the assessment computed tomography osteochondral allograft (ACTOCA) score.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We prospectively collected data from all consecutive patients who underwent FOCA transplantation for osteochondral knee lesions at one institution between August 2017 and August 2019. All patients were followed up for a minimum of 2 years. CT scans performed 6 months after surgery were evaluated by a musculoskeletal radiologist using the ACTOCA scoring system. The radiologist was blinded to the patient's medical history. Clinical outcomes were assessed preoperatively and at 12 and 30 months postoperatively using the International Knee Documentation Committee (IKDC) score, the Kujala score, the Tegner activity scale, and the Western Ontario Meniscal Evaluation Tool (WOMET) score.

RESULTS

A total of 38 cases were included. The ACTOCA score at 6 months after surgery showed a statistically significant correlation with clinical results at 12 and 30 months. The correlation was better at 30 months, showing a high negative correlation with the IKDC score (-0.663) and a moderate negative correlation with the Kujala, WOMET, and Tegner scores (-0.593; -0.547, and -0.593, respectively) (P < .001).

CONCLUSION

A statistically significant correlation between the mean ACTOCA score on CT scans at 6 months and the clinical results measured by the IKDC, Kujala, WOMET, and Tegner scores at 30 months confirmed the predictive value of the ACTOCA score for use in clinical practice.

Inconsistent Reporting of Preauthorization Medical Criteria for Osteochondral Allograft Transplantation Surgery

BACKGROUND

Although osteochondral allograft (OCA) transplantation has been a standard treatment for patients with osteochondral lesions, there is a disagreement in commercial payers' medical criteria regarding the definition of medical suitability and thus authorization for OCA transplantation. The primary goal of this study was to understand where consensus between a committee of experienced cartilage restoration surgeon scientists and payer policies existed and where there was significant disagreement.

METHODS

U.S. private payers were identified by reviewing health insurance market research literature. Medical criteria were then obtained from publicly available payer medical polices. A literature review was conducted to identify supporting evidence for consensus statements based on private payer medical criteria. The MOCA (Metrics of Osteochondral Allograft) Committee, 30 experienced surgeons and subject-matter experts in OCA transplantation, used a Likert scale of 1 (strongly disagree) to 5 (strongly agree) to rank each statement. The extent of agreement and disagreement among participants was measured for each statement. Consensus was defined as agreement or disagreement of >75%.

RESULTS

Fifty-seven statements regarding relevant medical criteria for OCA transplantation were included in the survey. All 30 MOCA Committee members completed the survey (100% response rate). Over half of the statements (52.6%) did not reach consensus. Of the remaining 27 statements that reached consensus, respondents agreed or strongly agreed with 16 statements, and disagreed or strongly disagreed with 11 statements. Inconsistent voting was observed for statements related to osteoarthritis, inflammation, and degenerative changes.

CONCLUSIONS

Commercial payers are not consistent in the medical criteria used to define patient eligibility for authorization of OCA transplantation. In contrast, an expert panel of cartilage surgeons reached a consensus that OCA transplantation was clearly suitable for a variety of specific indications. This study demonstrates the need to standardize medical criteria for cartilage restoration based on the most current literature, as well as in conjunction with experienced cartilage restoration experts.

LEVEL OF EVIDENCE

Therapeutic Level V . See Instructions for Authors for a complete description of levels of evidence.

Treatment of Cartilage Defects of the Knee in Military Tactical Athletes: An Overview of Management and Clinical Outcomes

Cartilage defects of the knee are a common problem that can be caused by trauma or chronic repetitive overload and result in debilitating functional limitations. These consequences are of particular significance to military service members, who, by in large, are a group of young, active individuals with professional duties requiring full, unrestricted activity and function. The burden of knee chondral-related disease among military tactical athletes is well established, and systematic approach to the evaluation of a military member with suspected knee chondral pathology facilitates the execution of a surgical procedure that maximizes the likelihood of a return to duty. Despite advances in cartilage restoration surgery, chondral pathology of the knee remains a vexing problem and an omnipresent threat to military medical readiness and warfighter lethality.

Osteochondral Allografts in Knee Surgery: Narrative Review of Evidence to Date

Knee articular cartilage defects can result in significant pain and loss of function in active patients. Osteochondral allograft (OCA) transplantation offers a single-stage solution to address large chondral and osteochondral defects by resurfacing focal cartilage defects with mature hyaline cartilage. To date, OCA transplantation of the knee has demonstrated excellent clinical outcomes and long-term survivorship. However, significant variability still exists among clinicians with regard to parameters for graft acceptance, surgical technique, and rehabilitation. Technologies to optimize graft viability during storage, improve osseous integration of the allograft, and shorten recovery timelines after surgery continue to evolve. The purpose of this review is to examine the latest evidence on treatment indications, graft storage and surgical technique, patient outcomes and survivorship, and rehabilitation after surgery.

Osteochondral Allograft Transplantation Of Posterior Femoral Condyle Lesions Utilizing An Open Posterior Approach To The Knee

Osteochondral allograft transplantation is a viable option for large chondral defects >2 cm squared, as well as in a revision setting after failure of a previous surface chondral restoration procedure. Osteochondral lesions involving the posterior aspect of the femoral condyle, however, are less common and easily underappreciated. Treatment of posterior osteochondral lesions is more technically demanding because they cannot be adequately addressed through standard arthroscopic approaches or an anterior arthrotomy. The challenges of the posterior approach include the relative unfamiliarity for many surgeons and the inherent risks due to the proximity of the neurovascular structures. The following technique reviews relevant anatomy and approach to osteochondral allograft transplant involving the posterior femoral condyles.

Computerized tomography scan evaluation after fresh osteochondral allograft transplantation of the knee correlates with clinical outcomes

Purpose

To determine the correlation between the assessment computed tomography osteochondral allograft (ACTOCA) scoring system and clinical outcomes scores. The hypothesis was that the ACTOCA score would show sufficient correlation to support its use in clinical practice.

Methods

We prospectively collected data from all consecutive patients who underwent cartilage restitution with fresh osteochondral allograft (FOCA) transplantation for osteochondral lesions of the knee and had a minimum follow-up of two years. CT scans were performed at three, six and 24 months post-operatively. A musculoskeletal radiologist blinded to the patients’ medical history evaluated the scans using the ACTOCA scoring system. Clinical outcomes collected preoperatively and at three, six and 24 months postoperatively were evaluated using the International Knee Documentation Committee (IKDC), Kujala, the Western Ontario Meniscal Evaluation Tool (WOMET), and the Tegner Activity Scale.

Results

The mean total ACTOCA score showed a statistically significant correlation with the clinical outcome. The correlation was optimal at 24 months. We found a high negative correlation with the IKDC, Kujala and Tegner (− 0.737; − 0.757, and − 0.781 respectively), and a moderate negative correlation with WOMET (− 0.566) (p < 0.001). IKDC, Kujala, WOMET, and Tegner scores showed a significant continuous improvement in all scores (p < 0.001).

Conclusion

The mean total ACTOCA score showed a linear correlation with clinical results in IKDC, Kujala, WOMET, and Tegner scores, being the highest at 24 months post-surgery. This finding supports the use of ACTOCA to standardize CT scan reports following fresh osteochondral allograft transplantation in the knee.

Correlation of Postoperative Imaging With MRI and Clinical Outcome After Cartilage Repair of the Ankle: A Systematic Review and Meta-analysis

Background

Magnetic resonance imaging (MRI) is commonly used for evaluation of ankle cartilage repair, yet its association with clinical outcome is controversial. This study analyzes the correlation between MRI and clinical outcome after cartilage repair of the talus including bone marrow stimulation, cell-based techniques, as well as restoration with allo- or autografting.

Methods

A systematic search was performed in MEDLINE, Embase, and Cochrane Collaboration. Articles were screened for correlation of MRI and clinical outcome. Guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were used. Chi-square test and regression analysis were performed to identify variables that determine correlation between clinical and radiologic outcome.

Results

Of 2687 articles, a total of 43 studies (total 1212 cases) were included with a mean Coleman score of 57 (range, 33-70). Overall, 93% were case series, and 5% were retrospective and 2% prospective cohort studies. Associations between clinical outcome and ≥1 imaging variable were found in 21 studies (49%). Of 24 studies (56%) using the composite magnetic resonance observation of cartilage repair tissue (MOCART) score, 7 (29%) reported a correlation of the composite score with clinical outcome. Defect fill was associated with clinical outcome in 5 studies (12%), and 5 studies (50%) reported a correlation of T2 mapping and clinical outcome. Advanced age, shorter follow-up, and larger study size were associated with established correlation between clinical and radiographic outcome (P = .021, P = .028, and P = .033).

Conclusion

Interpreting MRI in prediction of clinical outcome in ankle cartilage repair remains challenging; however, it seems to hold some value in reflecting clinical outcome in patients with advanced age and/or at a shorter follow-up. Yet, further research is warranted to optimize postoperative MRI protocols and assessments allowing for a more comprehensive repair tissue evaluation, which eventually reflect clinical outcome in patients after cartilage repair of the ankle.Level of Evidence: Level III, systematic review and meta-analysis.

Osteochondral Allograft for Unsalvageable Osteochondritis Dissecans in the Skeletally Immature Knee

Background:

While an excellent option for osteochondral defects in the adult knee, fresh osteochondral allograft (FOCA) in the skeletally immature adolescent knee has been infrequently studied.

Purpose:

To compare radiographic and patient-reported outcomes (PROs) in skeletally mature and immature adolescents after FOCA in the knee for treatment of unsalvageable osteochondritis dissecans (OCD).

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were 34 patients (37 knees) who underwent size-matched FOCA of the knee for unsalvageable OCD lesions. All patients were aged ≤19 years and had a minimum of 12 months of follow-up. Patient characteristics, lesion characteristics, reoperations, and PROs were evaluated and compared between patients with open physes (skeletally immature; n = 20) and those with closed physes (skeletally mature; n = 17). Graft failure was defined as the need for revision osteochondral grafting. Postoperative radiographs were analyzed at 1 year and the final follow-up for graft incorporation and classified as A (complete), B (≥50% healed), or C (<50% healed).

Results:

The mean patient age was 15.4 years (range, 9.6-17.6 years), and the mean follow-up was 2.1 years (range, 1-5.3 years). The mean graft size was 5.0 cm² and did not differ significantly between the study groups. Patients with open physes were younger (14.7 vs 16.2 years; P = .002) and more commonly male (80% vs 35%; P = .008). At the 1-year follow-up, 85% of immature patients and 82% of mature patients had radiographic healing grades of A or B. Patients with open physes were more likely to achieve complete radiographic union at 1 year (65% vs 15%; P = .007) and demonstrated better Knee injury and Osteoarthritis Outcome Score (KOOS) Daily Living (96.8 vs 88.5; P = .04) and KOOS Quality of Life (87.0 vs 56.8; P = .01) at the final follow-up. Complications were no different in either group, and graft failure occurred in only 1 skeletally mature patient with a trochlear lesion.

Conclusion:

FOCA treatment for unsalvageable OCD in the young knee may be expected to yield excellent early results. Despite the presence of open physes and immature epiphyseal osteochondral anatomy, equivalent or improved healing and PRO scores compared with those of skeletally mature patients may be expected.

Differences in Clinical and Functional Outcomes Between Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation for the Treatment of Focal Articular Cartilage Defects

Background:

Articular cartilage pathology can result from a spectrum of origins, including trauma, osteochondritis dissecans, avascular necrosis, or degenerative joint disease.

Purpose:

To compare the differences in clinical and patient-reported outcomes after autologous chondrocyte implantation (ACI) versus osteochondral allograft transplantation (OCA) in patients with focal articular cartilage defects without underlying bone loss.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective review identified patients who underwent ACI or OCA between 2008 and 2016 for isolated grades 3 and 4 articular cartilage defects without underlying bone loss. Outcome measures included the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), International Knee Documentation Committee (IKDC) evaluation, and 12-Item Short Form Health Survey–Physical Component (SF-12-P) scores. Defect location, size, complications, and rate of subsequent surgery were determined.

Results:

Overall, 148 patients were included: 82 (55%) underwent ACI and 66 (45%) underwent OCA. The mean age at the time of surgery was 31.2 years within the ACI cohort and 37.7 years within the OCA cohort (P < .001); the mean follow-up for both cohorts was 6.7 years (P = .902). Within the ACI group, 28 (34%) patients had multifocal defects, 21 (26%) had defects confined to the femoral condyles, and 33 (40%) had defects in the patellofemoral region. Within the OCA group, 23 (35%) patients had multifocal defects, 30 (46%) had confined femoral condyle lesions, and 13 (20%) had patellofemoral defects. When comparing by lesion location, there were no significant differences in KOOS JR, and IKDC scores between the ACI and OCA cohorts (P < .05). There was, however, a significant difference for SF-12-P scores for FDD trochlear lesions. In both cohorts, traumatic patellofemoral pathology demonstrated lower patient-reported outcomes and higher failure rates than degenerative lesions. The overall rate of failure, defined as graft failure with revision surgery and/or conversion to arthroplasty, was significantly greater in the OCA group (21% vs 4%; P = .002).

Conclusion:

Study results indicated that ACI provides similar outcomes to OCA with or without concomitant procedures for the treatment of symptomatic articular cartilage defects in all lesion locations and may have a lower revision rate for multifocal and condylar lesions.

Return-to-Play and Rehabilitation Protocols following Cartilage Restoration Procedures of the Knee: A Systematic Review

OBJECTIVE

The purpose of this study is to systematically review the literature and to evaluate the reported rehabilitation protocols, return-to-play guidelines, and subsequent rates of return to play following cartilage restoration procedures in the knee.

DESIGN

MEDLINE, EMBASE, and the Cochrane Library were searched according to the PRISMA guidelines to find studies on cartilage restoration procedures in the knee, including (1) microfracture (Mfx), (2) osteochondral autograft transfer (AOT), (3) osteochondral allograft implantation (OCA), and (4) autologous chondrocyte implantation (ACI). Studies were included if they reported return-to-play data or rehabilitation protocols.

RESULTS

Overall, 179 studies fit our inclusion criteria, with 48 on Mfx, 34 on AOT, 54 on OCA, and 51 on ACI. The rate of return to play was reported as high as 88.2% with AOT, and as low as 77.2% following OCA, with rates of return to play at the same/higher level as high as 79.3% with AOT, and as low as 57.3% following ACI. The average reported time of return to play was as low as 4.9 months with AOT, and as high as 11.6 months following ACI.

CONCLUSIONS

The majority of patients are able to return to play following cartilage restoration procedures in the knee, regardless of surgical procedure utilized. However, while the rate of return to play at the same level was similar to the overall rate of return following AOT, there was a large number of patients unable to return to the same level following Mfx, OCA, and ACI. Additionally, there is wide variety in the rehabilitation protocols, and scant literature on return-to-play protocols.

No Difference in Outcomes Following Osteochondral Allograft with Fresh Precut Cores Compared to Hemi-Condylar Allografts

OBJECTIVE

The purpose of the current study is to evaluate the clinical and radiographic outcomes at early to midterm follow-up between fresh precut cores versus hemi-condylar osteochondral allograft (OCAs) in the treatment of symptomatic osteochondral lesions.

DESIGN

A retrospective review of patients who underwent an OCA was performed. Patient matching between those with OCA harvested from an allograft condyle/patella or a fresh precut allograft core was performed to generate 2 comparable groups. The cartilage at the graft site was assessed with use of a modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system and patient-reported outcomes were collected.

RESULTS

Overall, 52 total patients who underwent OCA with either fresh precut OCA cores (n = 26) and hemi-condylar OCA (n = 26) were pair matched at a mean follow-up of 34.0 months (range 12 months to 99 months). The mean ages were 31.5 ± 10.7 for fresh precut cores and 30.9 ± 9.8 for hemi-condylar (P = 0.673). Males accounted for 36.4% of the overall cohort, and the mean lesion size for fresh precut OCA core was 19.6 mm² compared to 21.2 mm² for whole condyle (P = 0.178). There was no significant difference in patient-reported outcomes including Visual Analogue Scale, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, and Tegner (P > 0.5 for each), or in MOCART score (69.2 vs. 68.3, P = 0.93).

CONCLUSIONS

This study found that there was no difference in patient-reported clinical outcomes or MOCART scores following OCA implantation using fresh precut OCA cores or size matched condylar grafts at early to midterm follow-up.

Evaluation of Osseous Incorporation After Osteochondral Allograft Transplantation: Correlation of Computed Tomography Parameters With Patient-Reported Outcomes

BACKGROUND

Studies have reported favorable clinical outcomes after osteochondral allograft (OCA) transplantation to treat osteochondral defects and have demonstrated that healing of the osseous component may be critical to outcomes. However, there is currently no consensus on the optimal modality to evaluate osseous healing.

PURPOSE

To define parameters for OCA healing using computed tomography (CT) and to investigate whether osseous healing identified using CT is correlated with improved pain and function on patient-reported outcomes (PROs) collected closest in time to the postoperative CT scan and at final follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Of 118 patients who underwent OCA transplantation for articular cartilage defects of the knee over the 10-year study period, 60 were included in final analysis based on completion of CT scans at 5.8 ± 1.9 months postoperatively and PROs collected preoperatively and postoperatively. CT parameters, including osseous incorporation, bone density, subchondral bone congruency, and cystic changes, were summarized for each patient relative to the cohort. Parameters were assessed for inter- and intrarater reliability as well as for covariation with patient characteristics and surgical variables. Structural equation modeling was used to assess correlation of CT parameters with change in PROs from preoperatively to those collected closest in time to CT acquisition and at the final follow-up.

RESULTS

Bone incorporation was the most reliable CT parameter. The summarized scores for CT scans were normally distributed across the study population. Variance in CT parameters was independent of age, sex, body mass index, prior surgery, number of grafts, lesion size, and location. No significant correlation (P > .12 across all comparisons) was identified for any combination of CT parameter and change in PROs from baseline for outcomes collected either closest to CT acquisition or at the final follow-up (mean, 38.2 ± 19.9 months; range, 11.6-84.9 months). There was a uniformly positive association between change in PROs and host bone density but not graft bone density, independent of patient characteristics and surgical factors.

CONCLUSION

CT parameters were independent of clinical or patient variables within the study population, and osseous incorporation was the most reliable CT parameter. Metrics collected from a single postoperative CT scan was not correlated with clinical outcomes at ≥6-month longitudinal follow-up.

Rehabilitation and Return-to-Play Criteria After Fresh Osteochondral Allograft Transplantation: A Systematic Review

Background:

Fresh osteochondral allograft (OCA) is a treatment option that allows for the transfer of size-matched allograft cartilage and subchondral bone into articular defects of the knee. Although long-term studies show good functional improvement with OCA, there continues to be wide variability and a lack of consensus in terms of postoperative rehabilitation protocols and return to sport.

Purpose:

To systematically review the literature and evaluate the reported rehabilitation protocols after OCA of the knee, including weightbearing and range of motion (ROM) restrictions as well as return-to-play criteria.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

PubMed, EMBASE, Cumulative Index of Nursing Allied Health Literature, SPORTDiscus, and Cochrane databases were searched according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies on knee OCA. Studies were included if they reported return-to-play data or postsurgical rehabilitation protocols.

Results:

A total of 62 studies met the inclusion criteria, with a total of 3451 knees in 3355 patients. Concomitant procedures were included in 30 of these studies (48.4%). The most commonly cited rehabilitation protocols included weightbearing restrictions and ROM guidelines in 100% and 90% of studies, respectively. ROM was most commonly initiated within the first postoperative week, with approximately half of studies utilizing continuous passive motion. Progression to weightbearing as tolerated was reported in 60 studies, most commonly at 6 weeks (range, immediately postoperatively to up to 1 year). Of the 62 studies, 37 (59.7%) included an expected timeline for either return to play or return to full activity, most commonly at 6 months (range, 4 months to 1 year). Overall, 13 studies (21.0%) included either objective or subjective criteria to determine return to activity within their rehabilitation protocol.

Conclusion:

There is significant heterogeneity for postoperative rehabilitation guidelines and the return-to-play protocol after OCA of the knee in the literature, as nearly half of the included studies reported use of concomitant procedures. However, current protocols appear to be predominantly time-based without objective criteria or functional assessment. Therefore, the authors recommend the development of objective criteria for patient rehabilitation and return-to-play protocols after OCA of the knee.

Osteochondral allograft transplantation in the knee, after prolonged fresh storage at 37°C. Determination of viability of human cartilage allografts, indications, technique, and evidence. Follow up 10 years

BACKGROUND

Osteochondral allografts (OA) kept fresh for a long time, are presented as a viable option for the treatment of large chondral and osteochondral lesions.

GOALS

Chondrocyte viability decreases substantially when allografts are stored for more than 15 days. The objective of this work is to validate the viability and clinical and functional results of OA transplantation stored at 37°C in a cell culture medium, applied in cartilage defects of the knee, defining the means and limits of allograft storage, among 15 and 28 days after extraction.

PATIENTS AND METHOD

This study presents the results of 20 consecutive patients, operated between 2003 and 2019, who underwent a fresh-preserved osteochondral allograft, implanted on cartilage defects of the femoral condyle and patella. The minimum follow-up time was 10 years and the maximum 17. The mean age of the patients was 29 (14-44). The clinical control data were collected using International Knee Documentation Committee (IKDC) (knee-specific), Knee injury and Osteoarthritis Outcome Score (KOOS) protocols. Likewise, the degree of satisfaction was evaluated. Cartilage control was performed using the International Cartilage Repair Society Score (ICRS) and the Oswestry Arthroscopy Score (OAS). Radiological evaluations were performed using MRI and helical CT.

RESULTS

Statistically significant improvements, P<.0001, were observed for the IKDC: 30-65; the 5 components of the KOOS protocol, pain; 66-85; specific symptoms: 72-82; activities of daily living: 74-91; sports and recreational function: 37-70; related to the knee, quality of life: 25-60. Regarding the degree of satisfaction, 89% answered being satisfied or very satisfied. The ICRS and OAS results, all patients went from grade IV to grade I, except for one who is currently in IV. The incorporation of the graft in the recipient area occurred at three months, verified by helical CT and MRI.

CONCLUSION

Osteochondral allograft transplants stored fresh at 37°C are established as a long-term solution for the treatment of localized osteochondral defects in the knee.

Chondral Lesions of the Knee: An Evidence-Based Approach

➤

Management of chondral lesions of the knee is challenging and requires assessment of several factors including the size and location of the lesion, limb alignment and rotation, and the physical and mental health of the individual patient.

➤

There are a multitude of options to address chondral pathologies of the knee that allow individualized treatment for the specific needs and demands of the patient.

➤

Osteochondral autograft transfer remains a durable and predictable graft option in smaller lesions (<2 cm2) in the young and active patient population.

➤

Both mid-term and long-term results for large chondral lesions (≥3 cm2) of the knee have demonstrated favorable results with the use of osteochondral allograft or matrix-associated chondrocyte implantation.

➤

Treatment options for small lesions (<2 cm2) include osteochondral autograft transfer and marrow stimulation and/or microfracture with biologic adjunct, while larger lesions (≥2 cm2) are typically treated with osteochondral allograft transplantation, particulated juvenile articular cartilage, or matrix-associated chondrocyte implantation.

➤

Emerging technologies, such as allograft scaffolds and cryopreserved allograft, are being explored for different graft sources to address complex knee chondral pathology; however, further study is needed.

Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft

Background:

Osteochondral allograft (OCA) transplantation has evolved into a first-line treatment for large chondral and osteochondral defects, aided by advancements in storage protocols and a growing body of clinical evidence supporting successful clinical outcomes and long-term survivorship. Despite the body of literature supporting OCAs, there still remains controversy and debate in the surgical application of OCA, especially where high-level evidence is lacking.

Purpose:

To develop consensus among an expert group with extensive clinical and scientific experience in OCA, addressing controversies in the treatment of chondral and osteochondral defects with OCA transplantation.

Study Design:

Consensus statement.

Methods:

A focus group of clinical experts on OCA cartilage restoration participated in a 3-round modified Delphi process to generate a list of statements and establish consensus. Questions and statements were initially developed on specific topics that lack scientific evidence and lead to debate and controversy in the clinical community. In-person discussion occurred where statements were not agreed on after 2 rounds of voting. After final voting, the percentage of agreement and level of consensus were characterized. A systematic literature review was performed, and the level of evidence and grade were established for each statement.

Results:

Seventeen statements spanning surgical technique, graft matching, indications, and rehabilitation reached consensus after the final round of voting. Of the 17 statements that reached consensus, 11 received unanimous (100%) agreement, and 6 received strong (80%-99%) agreement.

Conclusion:

The outcomes of this study led to the establishment of consensus statements that provide guidance on surgical and perioperative management of OCAs. The findings also provided insights on topics requiring more research or high-quality studies to further establish consensus and provide stronger evidence.

A new computed tomography scoring system to assess osteochondral allograft transplantation for the knee: inter-observer and intra-observer agreement

AIM OF THE STUDY

To describe a new semiquantitative computed tomography (CT) scoring system for multi-feature analysis of cartilage defect repair by osteochondral allografts for the knee and to assess its intra-observer and inter-observer variability.

METHOD

A semiquantitative assessment CT osteochondral allograft (ACTOCA) scoring system was designed based on fresh osteochondral allograft transplantations for the knee. The system includes five CT features: density relative to host bone, integration at the host-graft junction, surface percentage with a discernible cleft at the host-graft junction, cystic changes, and intra-articular fragments. Inter-observer variability was calculated by three observers blinded to the patient's medical history and treatment. Intra-observer variability was also determined.

RESULTS

Inter-observer agreement was moderate to substantial for all CT score components and intra-observer agreement was moderate to almost perfect for all CT score components (κ > 0.5, p < 0.05).

CONCLUSION

The ACTOCA score is a reliable tool to evaluate integration of osteochondral allograft transplantations. It provides an accurate evaluation of bone changes and may help to standardize CT scan reports following osteochondral allograft transplantation for the knee.

Measuring Outcomes in Knee Articular Cartilage Pathology

Measuring outcomes following treatment of knee articular cartilage lesions is crucial to determine the natural history of disease and the efficacy of treatments. Outcome assessments for articular cartilage treatments can be clinical (based on failure, lack of healing, reoperation, need for arthroplasty), radiographic (X-ray, MRI), histologic, or patient reported and functional. The purpose of this review is to discuss the application and properties of patient-reported outcomes (PROs) with a focus on articular cartilage injuries and surgery in the knee. The most frequently used and validated PROs for knee articular cartilage studies include: the Knee injury and Osteoarthritis and Outcome Score, International Knee Documentation Committee Subjective Knee Form, and Lysholm score as knee-specific measures; the Marx Activity Rating Scale and Tegner Activity Scale as activity measures; and EQ-5D and SF-36/12 as generic quality-of-life measures. Incorporating these validated PROs in studies pertaining to knee articular cartilage lesions will allow researchers to fully capture clinically relevant outcomes that are most important to patients.

Patient-Reported Outcomes Measurement Information System (PROMIS) Instruments Correlate Better With Legacy Measures in Knee Cartilage Patients at Postoperative Than at Preoperative Assessment

PURPOSE

To define the psychometric properties of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF), Pain Interference (PI), and Depression computer adaptive tests (CATs) in patients undergoing knee cartilage surgical procedures.

METHODS

The PROMIS PF, PI, and Depression CATs were administered preoperatively and at 6 months alongside legacy knee patient-reported outcome measures (PROMs) in patients undergoing knee cartilage surgical procedures. Statistical analysis consisted of the time to completion, psychometric analysis for correlative strengths, absolute and relative floor and ceiling effects, and Cohen effect size.

RESULTS

Our study included 250 patients (57.2% male patients), averaging 1.87, 1.53, and 1.91 minutes for completion of the PF, PI, and Depression CATs, respectively. Preoperatively, the PROMIS PF and PI CATs showed wide ranges of correlation coefficients with respect to function (r = 0.14-0.72 and r = 0.29-0.77, respectively) and health-related quality-of-life PROMs (r = 0.64-0.70). At 6 months, the PROMIS PF CAT (r = 0.82-0.93) and PI CAT (r = 0.77-0.93) both exhibited excellent correlations with respect to legacy function and health-related quality-of-life PROMs except for the Marx Activity Rating Scale (r = 0.36-0.44). None of the PROMIS instruments exhibited any significant floor or ceiling effects.

CONCLUSIONS

The PROMIS PF, PI, and Depression CATs performed better with respect to legacy PROMs in the postoperative period than the preoperative period. In addition, the PROMIS PF and PI measures performed best with respect to the International Knee Documentation Committee questionnaire, and no floor or ceiling effects were identified for the PROMIS instruments. The PROMIS instruments may be more suited to track outcomes postoperatively than to establish preoperative baselines in cartilage surgery patients.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Effect of Autogenous Bone Marrow Aspirate Treatment on Magnetic Resonance Imaging Integration of Osteochondral Allografts in the Knee: A Matched Comparative Imaging Analysis

PURPOSE

To accurately evaluate the effects of bone marrow aspirate (BMA) augmentation on osteochondral allograft (OCA) integration on early postoperative magnetic resonance imaging (MRI) using the comprehensive Osteochondral Allograft MRI Scoring System (OCAMRISS).

METHODS

This imaging study compared patients who underwent OCA transplantation with and without BMA augmentation for the treatment of focal osteochondral defects in the knee performed by a single surgeon between July 2013 and July 2017. Patients were excluded if they underwent implantation of premade plugs, had an overlapping OCA configuration ("snowman" technique), or did not undergo MRI at 6 months postoperatively. Patients were matched by lesion location, lesion size, age, and body mass index, as well as whether they underwent previous surgical procedures. Data were analyzed using descriptive statistics, Spearman correlation, the independent t test, the Mann-Whitney U test, and the χ² test.

RESULTS

A total of 58 patients (29 per group) were included in this study, with an average age of 36.4 ± 10.1 years and mean body mass index of 28.6 ± 5.1. The mean size of the analyzed OCA plugs was 3.3 ± 1 cm². At an average imaging follow-up of 5.6 ± 1 months, 86.2% of the grafts had achieved osseous integration at the graft-host junction and 75.9% did not show any cystic changes in the subchondral bone. No difference in any OCAMRISS subscale was seen comparing OCAs with and without BMA augmentation (P > .05). Specifically, osseous integration and subchondral cyst formation were comparable between groups (P = .128 and P = .539, respectively).

CONCLUSIONS

OCAs showed excellent osseous integration at the graft-host junction on 6-month postoperative MRI. The treatment of OCAs with autogenous BMA did not result in superior imaging outcomes when analyzed using the OCAMRISS.

LEVEL OF EVIDENCE

Level III, case-control study.

Patellar Fresh Osteochondral Allograft Transplantation

Chondral defects of the patellofemoral joint remain a difficult-to-treat pathology with limited long-term results. Currently available techniques to treat large or unipolar chondral defects of the patella include autologous chondrocyte implantation and osteochondral allograft transplantation. Despite the recent advances in orthobiologic adjuncts, there is no single gold-standard surgical approach to this difficult-to-treat pathology in patients who are frequently young, active, and demanding on their bodies. We describe a technique for osteochondral allograft transplantation to the patella for an isolated patellar chondral lesion (unipolar).