Osteochondral Allograft Transplantation of the Knee: Analysis of Failures at 5 Years

Topographic Analysis of Lateral Versus Medial Femoral Condyle Donor Sites for Oblong Medial Femoral Condyle Lesions

PURPOSE

To analyze the topographic matching of oblong osteochondral allografts to treat large oval medial femoral condyle (MFC) lesions using computer simulation models. The secondary objective was to determine whether lateral femoral condyle (LFC) grafts would have a similar surface matching when compared with MFC grafts in this setting.

METHODS

Human femoral hemicondyles (10 MFCs, 7 LFCs) underwent 3-dimensional computed tomography. Models were created from computed tomography images and exported into point-cloud models. Donor-recipient matches with large condylar width mismatch were excluded. The remaining specimen were divided into 3 donor-recipient groups with 2 defect sizes (17 × 30 mm and 20 × 30 mm): 20 MFC donor (MFCd)-MFC recipient (MFCr), 27 ipsilateral LFC donor (LFCd)-MFCr, and 26 contralateral LFCd-MFCr. Grafts were optimally virtually aligned with the MFCr defect. Mismatch of the articular cartilage and subchondral bone surfaces between the graft and the defect and articular step-off were calculated.

RESULTS

MFCd grafts resulted in articular cartilage surface mismatch and peripheral step of less than 0.5 mm for both defect sizes. The subchondral bone surface mismatch was significantly greater than the articular cartilage surface mismatch (P < .01) in both defect sizes). Conversely, the ipsilateral and contralateral LFCd grafts resulted in significantly greater articular cartilage surface mismatch and step-off for both defect sizes when compared to MFCd grafts (P < .01).

CONCLUSIONS

Oblong MFC allografts provide acceptable topographic matching for large oval MFC lesions when condylar width differences are minimized. However, concern exists in using oblong LFC allografts for MFC defects, as this can result in increased peripheral step-off and surface mismatch.

CLINICAL RELEVANCE

These data reinforce the ability to use oblong MFC osteochondral allograft for treating oval cartilage lesions of the MFC when condylar width is considered. Although other studies have demonstrated LFCs can be used to treat circular defects on the MFC, this may not be true for oblong grafts.

Editorial Commentary: Knee Lateral Femoral Osteochondral Allografts Are Not Recommended for Medial Femoral Condylar Defects: If the Shoe Doesn't Fit, Don't Wear It!

Treatment of large articular cartilage defects of the knee is challenging, particularly in young, high-demand patients. Osteochondral allograft (OCA) transplantation is a viable treatment option, providing fully mature articular cartilage during a single operation while avoiding donor site morbidity. Indications are symptomatic, full-thickness articular cartilage defects >3 cm². Contraindications include a "kissing" lesion of the corresponding articular cartilage surface, uncorrected ligamentous instability, malalignment, peripheral osteophytes, joint-space narrowing, or absence of >50% of the meniscus in the affected compartment. Matching for size and contour is crucial; therefore, we use medial femoral condyle (MFC) allografts for MFC lesions and lateral femoral condyle (LFC) allografts for LFC lesions, and do not recommend LFC grafts for the MFC. Survival rates are 78.7% and 72.8% at 10 and 15 years, respectively.

Shorter Storage Time Is Strongly Associated With Improved Graft Survivorship at 5 Years After Osteochondral Allograft Transplantation

BACKGROUND

Current regulations surrounding the use of osteochondral allografts (OCAs) in the United States require delayed graft release after 14 days to complete infectious disease screening. With a generally accepted expiration time of 28 days in storage, a limited window from 14 to 28 days remains for implantation. Yet, the rates of graft survival and thus optimal time for transplantation within this window remain largely unknown.

HYPOTHESIS

OCAs transplanted within 19 to 24 days would have lower failure rates at 5 years than those transplanted at 25 to 27 days.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In this retrospective case series, we analyzed data from patients who underwent OCA transplantation (N = 111) by a single surgeon between February 2014 and December 2016 with at least 2-year follow-up. In total, 56 patients received early transplant grafts (storage time, 19-24 days), and 55 received late transplant grafts (storage time, 25-27 days). Survival analysis with Kaplan-Meier curves was performed using log-rank analysis to compare the groups. Multivariable Cox regression analysis was used to assess the influence of OCA storage duration on graft survival while adjusting for age and defect size. Optimal storage time cutoff associated with graft failure was identified by performing receiver operating characteristic curve analysis and calculating the area under the curve.

RESULTS

Patients in the late transplant group had a significantly lower rate of graft survival at 5 years postoperatively (70.4%) as compared with patients in the early transplant group (93.1%; P = .027). When correcting for patient age and defect size, late transplant OCAs demonstrated a 3.4-times greater likelihood of failure versus early transplant OCAs. Receiver operating characteristic analysis suggested that OCA transplantation should ideally occur before 25 days of graft storage.

CONCLUSION

OCA transplantation is a safe and successful treatment option for large osteochondral defects of the knee, with excellent rates of in situ graft survival at 5 years. Prioritizing early transplantation of OCAs to <25 days in storage improves rates of graft survival.

Bipolar Osteochondral Allograft Transplantation of the Patella and Trochlea

OBJECTIVE

To evaluate clinical, functional, and radiographic outcomes of patients who underwent bipolar osteochondral allograft transplantation (OCAT) of the patellofemoral joint (PFJ).

DESIGN

Prospectively collected data on 18 knees who underwent fresh osteochondral allograft transplantation of the patella and trochlea by a single surgeon were reviewed. Inclusion criteria were: high-grade chondral lesions of PFJ (5 knees), or recurrent patella dislocations with trochlear dysplasia and chondral injury to the patella and/or trochlea (13 knees). Functional scores were obtained preoperatively and at follow-up appointments included Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), Oxford, Cincinnati, Tenger-Lysholm, visual analogue scale (VAS)-pain, and Single Assessment Numeric Evaluation (SANE). Grafts were also evaluated using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

Three patients were lost to follow-up, leaving 4 knees in group 1, and 11 knees in group 2. Average age was 28.9 years (range 16-52 years). The average follow-up was 33.2 months (range 12-64 months). There was significant improvement of KOOS (from 38.7 to 83.1), IKDC (from 28.2 to 76.6), Tegner-Lysholm (from 38.3 to 88.3), Oxford (from 22.7 to 42.9), Cincinnati (from 35.1 to 83.6), VAS (from 71 to 17.9.), and SANE (from 43.3 to 83) (P < 0.0001). The OCAMRISS score for patella was 2.23 and for trochlea 4.69. There were no revisions or conversions to arthroplasty.

CONCLUSION

Bipolar OCAT of the patella and trochlea provide significant improvement in functional outcomes, relief from pain, activity level, and prevent recurrent instability.

Return to Sport Following High Tibial Osteotomy With Concomitant Osteochondral Allograft Transplantation

BACKGROUND

Young patients with symptomatic chondral defects in the medial compartment with varus malalignment may undergo opening wedge high tibial osteotomy (HTO) with concomitant osteochondral allograft transplantation (OCA) (HTO + OCA). Although patients have demonstrated favorable outcomes after HTO + OCA, limited information is available regarding return to sporting activities after this procedure.

PURPOSE

To evaluate (1) the timeline to return to sports (RTS), (2) patient satisfaction, and (3) reasons for discontinuing sporting activity after HTO + OCA, and to identify predictive factors of RTS.

STUDY DESIGN

Case series; level of evidence, 4.

METHODS

Consecutive patients who underwent HTO + OCA for varus deformity and medial femoral condyle focal chondral defects with a minimum 2-year follow-up were retrospectively reviewed. Patients completed a subjective sports questionnaire, satisfaction questionnaire, visual analog scale for pain, and Single Assessment Numerical Evaluation.

RESULTS

Twenty-eight patients with a mean age of 36.97 ± 7.52 years were included at mean follow-up of 6.63 ± 4.06 years. Fourteen patients (50.0%) required reoperation during the follow-up period, with 3 (10.7%) undergoing knee arthroplasty. Twenty-four patients participated in sports within 3 years before surgery, with 19 patients (79.2%) able to return to at least 1 sport at a mean 11.41 ± 6.42 months postoperatively. However, only 41.7% (n = 10) were able to return to their preoperative level. The most common reasons for sports discontinuation (n = 20; 83.3%) were a desire to prevent further damage to the knee (70.0%), persistent pain (55.0%), persistent swelling (30.0%), and fear (25.0%).

CONCLUSION

In young, active patients with varus deformity and focal medial femoral condyle chondral defects, HTO + OCA enabled 79.2% of patients to RTS by 11.41 ± 6.42 months postoperatively. However, only 41.7% of patients were able to return to their preinjury level or better. It is imperative that patients be appropriately educated to manage postoperative expectations regarding sports participation after HTO + OCA.

Patellofemoral Cartilage Restoration: A Systematic Review and Meta-analysis of Clinical Outcomes

BACKGROUND

Many surgical options for treating patellofemoral (PF) cartilage lesions are available but with limited evidence comparing their results.

PURPOSE

To determine and compare outcomes of PF cartilage restoration techniques.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines were followed by utilizing the PubMed, EMBASE, and Cochrane Library databases. Inclusion criteria were clinical studies in the English language, patient-reported outcomes after PF cartilage restoration surgery, and >12 months' follow-up. Quality assessment was performed with the Coleman Methodology Score. Techniques were grouped as osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocyte cell-based therapy, bone marrow-based therapy, and scaffolds.

RESULTS

A total of 59 articles were included. The mean Coleman Methodology Score was 71.8. There were 1937 lesions (1077 patellar, 390 trochlear, and 172 bipolar; 298 unspecified). The frequency of the procedures was as follows, in descending order: chondrocyte cell-based therapy (65.7%), bone marrow-based therapy (17.2%), OAT (8%), OCA (6.6%), and scaffolds (2.2%). When compared with the overall pooled lesion size (3.9 cm²; 95% CI, 3.5-4.3 cm²), scaffold (2.2 cm²; 95% CI, 1.8-2.5 cm²) and OAT (1.5 cm²; 95% CI, 1.1-1.9 cm²) lesions were smaller (P < .001), while chondrocyte cell-based therapy lesions were larger (4.7 cm²; 95% CI, 4.1-5.3 cm²; P = .039). Overall, the instability pool was 11.9%, and the anatomic risk factors pool was 32.1%. Statistically significant improvement was observed on at least 1 patient-reported outcome in chondrocyte cell-based therapy (83%), OAT (78%), OCA (71%), bone marrow-based therapy (64%), and scaffolds (50%). There were no significant differences between any group and the overall pooled change in International Knee Documentation Committee score (30.2; 95% CI, 27.4-32.9) and Lysholm score (25.2; 95% CI, 16.9-33.5). There were no significant differences between any group and the overall pooled rate in minor complication rate (7.6%; 95% CI, 4.7%-11.9%) and major complication rate (8.3%; 95% CI, 5.7%-12.0%); however, OCA had a significantly greater failure rate (22.7%; 95% CI, 14.6%-33.4%) as compared with the overall rate (6.8%; 95% CI, 4.7%-9.5%).

CONCLUSION

PF cartilage restoration leads to improved clinical outcomes, with low rates of minor and major complications. There was no difference among techniques; however, failures were higher with OCA.

An Expert Consensus Statement on the Management of Large Chondral and Osteochondral Defects in the Patellofemoral Joint

Background

Cartilage lesions of the patellofemoral joint constitute a frequent abnormality. Patellofemoral conditions are challenging to treat because of complex biomechanics and morphology.

Purpose

To develop a consensus statement on the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint using a modified Delphi technique.

Study Design

Consensus statement.

Methods

A working group of 4 persons generated a list of statements related to the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint to form the basis of an initial survey for rating by a group of experts. The Metrics of Osteochondral Allografts (MOCA) expert group (composed of 28 high-volume cartilage experts) was surveyed on 3 occasions to establish a consensus on the statements. In addition to assessing agreement for each included statement, experts were invited to propose additional statements for inclusion or to suggest modifications of existing statements with each round. Predefined criteria were used to refine statement lists after each survey round. Statements reaching a consensus in round 3 were included within the final consensus document.

Results

A total of 28 experts (100% response rate) completed 3 rounds of surveys. After 3 rounds, 36 statements achieved a consensus, with over 75% agreement and less than 20% disagreement. A consensus was reached in 100.00% of the statements relating to functional anatomy of the patellofemoral joint, 88.24% relating to surgical indications, 100.00% relating to surgical technical aspects, and 100.00% relating to rehabilitation, with an overall consensus of 95.5%.

Conclusion

This study established a strong expert consensus document relating to the functional anatomy, surgical indications, donor graft considerations for osteochondral allografts, surgical technical aspects, and rehabilitation concepts for the management of large chondral and osteochondral defects in the patellofemoral joint. Further research is required to clinically validate the established consensus statements and better understand the precise indications for surgery as well as which techniques and graft processing/preparation methods should be used based on patient- and lesion-specific factors.

Particulated juvenile articular cartilage allograft transplantation for osteochondral lesions of the knee and ankle

Introduction: Osteochondral lesions have been challenging to treat due to the limited regenerative capacity of native hyaline cartilage. Although surgical options are available, a newer technique, Particulated Juvenile Cartilage Allograft Transplantation (PJCAT) has shown promise for lesions of the knee and ankle. Short-term studies have been encouraging of its use, but there is still limited evidence of its long-term durability.Areas covered: This review will summarize the surgical options currently available for osteochondral lesions, outline the indications and contraindications of PJCAT, present the basic science and clinical evidence of the procedure, and describe the surgical approaches of this technique.Expert opinion: PJCAT is a promising method to treat osteochondral lesions. However, continued research is needed to document the efficacy of this technique and potential superiority over other techniques. Benefits include ease of application, potential for arthroscopic or minimally invasive delivery, no need for perpendicular access, no donor site morbidity, and delivery of viable chondrocytes in hyaline cartilage.

The Influence of Physeal Status on Rate of Reoperation After Arthroscopic Screw Fixation for Symptomatic Osteochondritis Dissecans of the Knee

PURPOSE

To determine if physeal status or other preoperative or intraoperative variables influence the failure rate after arthroscopic reduction and internal fixation of osteochondritis dissecans (OCD) lesions in the knee.

METHODS

Consecutive patients undergoing screw fixation of osteochondral fragments from OCD by a single surgeon from 2005 to 2015 with a minimum 2-year follow-up were included. Demographic, preoperative imaging, and intraoperative data were analyzed to determine risk factors associated with failure, which was defined as the need for a revision reoperation or arthroplasty after initial OCD fixation.

RESULTS

A total of 45 knees met the inclusion criteria, including 26 skeletally mature patients and 19 patients with incompletely closed physes on preoperative imaging. The mean ages of the skeletally mature and immature groups were 18.3 ± 2.5 years and 14.9 ± 2.2 years, respectively (P < .001), and the mean body mass index values were 24.3 ± 3.6 and 23.2 ± 4.0, respectively (P = .432). We excluded 10 patients from the survivorship analysis because they had less than 2 years' follow-up. No statistically significant difference in failure rates was found between skeletally mature and immature individuals (30% and 40%, respectively; P = .721). The only factor significantly associated with fixation failure was undergoing a prior surgical procedure to address the OCD lesion (P = .038). Kaplan-Meier analysis showed rates of overall survivorship from revision reoperations of 88.6% at 1 year and 68.8% at 5 years.

CONCLUSIONS

Outcomes after internal fixation of OCD fragments are guarded, with a fragment survival rate of 65.7% at a mean of 4.1 years' follow-up. No difference in fragment survival was noted in skeletally mature versus immature patients. The only independent risk factor identified for fixation failure was the number of previous operations. LEVEL OF EVIDENCE: Level IV, case series with subgroup analysis.

Cost-efficacy of Knee Cartilage Defect Treatments in the United States

BACKGROUND

Multiple knee cartilage defect treatments are available in the United States, although the cost-efficacy of these therapies in various clinical scenarios is not well understood.

PURPOSE/HYPOTHESIS

The purpose was to determine cost-efficacy of cartilage therapies in the United States with available mid- or long-term outcomes data. The authors hypothesized that cartilage treatment strategies currently approved for commercial use in the United States will be cost-effective, as defined by a cost <$50,000 per quality-adjusted life-year over 10 years.

STUDY DESIGN

Systematic review.

METHODS

A systematic search was performed for prospective cartilage treatment outcome studies of therapies commercially available in the United States with minimum 5-year follow-up and report of pre- and posttreatment International Knee Documentation Committee subjective scores. Cost-efficacy over 10 years was determined with Markov modeling and consideration of early reoperation or revision surgery for treatment failure.

RESULTS

Twenty-two studies were included, with available outcomes data on microfracture, osteochondral autograft, osteochondral allograft (OCA), autologous chondrocyte implantation (ACI), and matrix-induced ACI. Mean improvement in International Knee Documentation Committee subjective scores at final follow-up ranged from 17.7 for microfracture of defects >3 cm² to 36.0 for OCA of bipolar lesions. Failure rates ranged from <5% for osteochondral autograft for defects requiring 1 or 2 plugs to 46% for OCA of bipolar defects. All treatments were cost-effective over 10 years in the baseline model if costs were increased 50% or if failure rates were increased an additional 15%. However, if efficacy was decreased by a minimum clinically important amount, then ACI (periosteal cover) of femoral condylar lesions ($51,379 per quality-adjusted life-year), OCA of bipolar lesions ($66,255) or the patella ($66,975), and microfracture of defects >3 cm² ($127,782) became cost-ineffective over 10 years.

CONCLUSION

Currently employed treatments for knee cartilage defects in the United States are cost-effective in most clinically acceptable applications. Microfracture is not a cost-effective initial treatment of defects >3 cm². OCA transplantation of the patella or bipolar lesions is potentially cost-ineffective and should be used judiciously.

Use of Allografts in Orthopaedic Surgery: Safety, Procurement, Storage, and Outcomes

The use of allografts has become a vital option for orthopaedic surgeons in the treatment of a variety of musculoskeletal lesions, ranging from osteochondral defects in the glenohumeral joint to meniscal deficiency in the young athlete. Nevertheless, barriers to treating a patient with an allograft-based procedure may arise from concerns over disease transmission, the navigation of tissue banks that supply allografts, the process of obtaining insurance approval, or optimal storage methods. This review serves to support orthopaedic surgeons in the incorporation of allografts into their practice by quelling these potential concerns. Fresh osteochondral allografts, fresh-frozen meniscal allografts, soft tissue allografts, and off-the-shelf cartilage products are the focus of this review amid broad overviews of allograft safety and tissue bank practices in the United States.

Surgical Trends in Articular Cartilage Injuries of the Knee, Analysis of the Truven Health MarketScan Commercial Claims Database from 2005-2014

Purpose

To evaluate trends in procedures for the treatment of chondral injuries of the knee using the MarketScan database in the hope that further work can be performed to refine the indications for chondral intervention

Methods

The MarketScan Research Database was searched using Current Procedure Terminology, 4th edition, codes to identify patients who underwent chondral procedures of the knee from 2005-2014. Combined procedures, including meniscal transplant or osteotomy, were also identified. Patients were characterized by gender, age group and year of initial procedure. A χ² test was used to evaluate differences in surgical trends between individual patient groups delineated by age and gender. The Cochran-Armitage trend test was used to identify significant differences in surgical trends yearly.

Results

Of 148,373,254 unique patients, 520,934 patients underwent a total of 599,119 procedures. Arthroscopy with debridement/shaving of articular cartilage decreased in proportion from 75% of all procedures in 2005 to 51% of all procedures in 2014 (P < .0001). Open osteochondral allograft saw the greatest change during the study period; a higher number of females than males underwent condral procedures (P < .0001). Patients aged 45-54 underwent the most procedures (32.9% of all procedures). A total of 483 patients underwent chondral procedures in conjunction with meniscal transplant with variable incidence during the study period. A total of 1,418 patients underwent chondral procedures in conjunction with osteotomy; cumulative incidence decreased from 4.5 procedures per 1,000,000 patients/year in 2005 to 2.6 procedures per 1,000,000 patients/year in 2014 (P < .0001).

Conclusions

Knee arthroscopy with debridement/shaving of articular cartilage remains the most common procedure performed. Although open allograft and autograft transplantation saw a sustained increase in incidence, the overall incidence of cartilage procedures, as well as those performed with osteotomies, declined.

Level of Evidence

Level IV, cross-sectional study.

Survivorship of Patellofemoral Osteochondral Allograft Transplantation

INTRODUCTION

We performed a survivorship analysis of patients treated with patellofemoral osteochondral allograft transplantation (OCA) using either a shell or plug technique and identified variables associated with graft failure.

METHODS

Consecutive patients at two institutions who underwent OCA of the patellofemoral compartment between March 1, 2001 to March 1, 2015, were retrospectively identified at minimum 2 years' follow-up. Demographic information, intraoperative findings, and postoperative data were collected. Patients were divided into two groups on the basis of surgical technique (plug group and shell group). Failure was defined as revision OCA, conversion to arthroplasty, or gross appearance of graft degeneration on second-look arthroscopy. Logistic regression analysis was performed to identify patient- and surgery-specific variables associated with survivorship.

RESULTS

Fifty patients were identified (36 women and 14 men; mean age 37.43 ± 8.87 years). Sixteen patients received plug allografts, whereas 34 received shell allografts. Forty percent of patients underwent a concomitant meniscal, ligamentous, malalignment, or chondral procedure. Five patients in the Plug Group (31.3%) underwent reoperation at a mean 1.37 ± 1.34 years, and 28 patients (82.4%) who received Shell OCA underwent reoperation at a mean 1.94 ± 1.92 years. Two patients in the plug group had graft failure at a mean 9.17 ± 0.93 years, whereas 13 patients in the shell group had graft failure at a mean 3.81 ± 2.78 years. Patients with plug allografts demonstrated 100% and 66% survival at 5 and 9.8 years, respectively. For the shell group, survivorship was 65.8% and 37% at 5 and 10.6 years, respectively. Increasing body mass index was associated with failure for the case series overall (odds ratio 1.33, P = .020). Traumatic cause was found to be protective of failure (odds ratio = 0.02, P = .035).

CONCLUSIONS

Plug OCA of the patellofemoral compartment can be an efficacious procedure with quality mid-term outcomes. Shell OCA led to high failure rates at midterm outcomes. Increasing body mass index may predispose patients to failure, whereas traumatic cause of their lesion was associated with improved outcomes.

LEVEL OF EVIDENCE

Level IV, Therapeutic case series.

Chondral Delamination of Fresh Osteochondral Allografts after Implantation in the Knee: A Matched Cohort Analysis

INTRODUCTION

Delamination of the chondral surface of an osteochondral allograft (OCA) from the underlying cancellous bone has been described as a mode of failure after implantation in the knee. Our hypothesis was that increased storage time of the OCA is associated with increased risk of graft delamination after implantation.

METHODS

Prospective data on 13 patients with evidence of OCA delamination identified on magnetic resonance imaging or during subsequent surgery from 2000 to 2015 were reviewed. A cohort of 33 patients without evidence of graft delamination were then matched to the delamination group based on recipient age, sex, body mass index (BMI), and chondral defect location. The matched cohort size was established based on a power calculation for determining differences in OCA storage times. All patients had a minimum 2-year follow-up.

RESULTS

There was no difference in donor age, donor sex, and graft storage time between groups (30 vs. 31 days, P = 0.78). There were no differences between number of previous ipsilateral knee surgeries (1.8 vs. 0.84, P = 0.26), BMI (26.8 vs. 25.0 kg/m², P = 0.31), total chondral defect size (6.5 vs. 5.8 cm², P = 0.41) or preoperative Marx activity scores between groups.

CONCLUSION

There is no association between OCA storage time, activity level scores, or number of previous ipsilateral knee surgeries and graft delamination in our patient population. Further work is needed to identify the etiology for this mode of failure of OCAs.

Osteochondral Allograft Transplantation in the Patellofemoral Joint: A Systematic Review

BACKGROUND

The initial focus of cartilage restoration algorithms has been on the femur; however, the patellofemoral compartment accounts for 20% to 30% of significant symptomatic chondral pathologies. While patellofemoral compartment treatment involves a completely unique subset of comorbidities, with a comprehensive and thoughtful approach many patients may benefit from osteochondral allograft treatment.

PURPOSE

To perform a systematic review of clinical outcomes and failure rates after osteochondral allograft transplantation (OCA) of the patellofemoral joint at a minimum 18-month follow-up.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature regarding the existing evidence for clinical outcomes and failure rates of OCA for patellofemoral joint chondral defects was performed with the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, and MEDLINE from studies published between 1990 and 2017. Inclusion criteria were as follows: clinical outcomes and failure rates of OCA for the treatment of chondral defects in the patellofemoral joint, English language, minimum follow-up of 18 months, minimum study size of 5 patients, and human studies. The methodological quality of each study was assessed with a modified version of the Coleman methodology score.

RESULTS

The systematic search identified 8 studies with a total of 129 patients. The methods of graft procurement and storage time included fresh (121 patients, 93.8%), and cryopreserved (8 patients, 6.2%) grafts. The mean survival rate was 87.9% at 5 years and 77.2% at 10 years. The following outcome scores showed significant improvement from pre- to postoperative status: modified d'Aubigné-Postel, International Knee Documentation Committee, Knee Society Score-Function, and Lysholm Knee Score.

CONCLUSION

OCA of the patellofemoral joint results in improved patient-reported outcome measures with high patient satisfaction rates. Five- and 10-year survival rates of 87.9% and 77.2%, respectively, can be expected after this procedure. These findings should be taken with caution, as a high percentage of patellofemoral osteochondral allografts were associated with concomitant procedures; therefore, further research is warranted to determine the effect of isolated osteochondral transplantations.

What are the prevalence and risk factors for repeat ipsilateral knee arthroscopy?

PURPOSE

The number of arthroscopic knee surgeries performed annually has increased over the last decade. It remains unclear what proportion of individuals undergoing knee arthroscopy is at risk for subsequent ipsilateral procedures. Better knowledge of risk factors and the incidence of reoperative ipsilateral arthroscopy are important in setting expectations and counselling patients on treatment options. The aim of this study is to determine the incidence of repeat ipsilateral knee arthroscopy, and the risk factors associated with subsequent surgery over long-term follow-up.

METHODS

The New York Statewide Planning and Research Cooperative Systems outpatient database was reviewed from 2003 to 2016 to identify patients who underwent elective, primary knee arthroscopy for one of the following diagnosis-related categories of procedures: Group 1: cartilage repair and transfer; Group 2: osteochondritis dissecans (OCD) lesions; Group 3: meniscal repair, debridement, chondroplasty, and synovectomy; Group 4: multiple different procedures. Subjects were followed for 10 years to determine the odds of subsequent ipsilateral knee arthroscopy. Risk factors including the group of arthroscopic surgery, age group, gender, race, insurance type, surgeon volume, and comorbidities were analysed to identify factors predicting subsequent surgery.

RESULTS

A total of 765,144 patients who underwent knee arthroscopy between 2003 and 2016, were identified. The majority (751,873) underwent meniscus-related arthroscopy. The proportion of patients undergoing subsequent ipsilateral knee arthroscopy was 2.1% at 1-year, 5.5% at 5 years, and 6.7% at 10 years of follow-up. Among patients who underwent subsequent arthroscopic surgery at 1-, 5-, and 10-year follow-up, there was a greater proportion of patients with worker's compensation insurance (p < 0.001), index operations performed by very high volume surgeons (p < 0.001), and cartilage restoration index procedures (p < 0.001), compared with those who never underwent repeat ipsilateral surgery.

CONCLUSION

Understanding the incidence of subsequent knee arthroscopy after index procedure in different age groups and the patterns over 10 years of follow-up is important in counselling patients and setting future expectations. The majority of subsequent surgeries occur within the first 5 years after index surgery, and subjects tend to have higher odds of ipsilateral reoperation for up to 10 years if they have worker's compensation insurance, or if their index surgery was performed by a very high volume surgeon, or was a cartilage restoration procedure.

LEVEL OF EVIDENCE

III.

Non-Destructive Spectroscopic Assessment of High and Low Weight Bearing Articular Cartilage Correlates with Mechanical Properties

OBJECTIVE

Autologous articular cartilage (AC) harvested for repair procedures of high weight bearing (HWB) regions of the femoral condyles is typically obtained from low weight bearing (LWB) regions, in part due to the lack of non-destructive techniques for cartilage composition assessment. Here, we demonstrate that infrared fiber optic spectroscopy can be used to non-destructively evaluate variations in compositional and mechanical properties of AC across LWB and HWB regions.

DESIGN

AC plugs (N = 72) were harvested from the patellofemoral groove of juvenile bovine stifle joints, a LWB region, and femoral condyles, a HWB region. Near-infrared (NIR) and mid-infrared (MIR) fiber optic spectra were collected from plugs, and indentation tests were performed to determine the short-term and equilibrium moduli, followed by gravimetric water and biochemical analysis.

RESULTS

LWB tissues had a significantly greater amount of water determined by NIR and gravimetric assay. The moduli generally increased in tissues from the patellofemoral groove to the condyles, with HWB condyle cartilage having significantly higher moduli. A greater amount of proteoglycan content was also found in HWB tissues, but no differences in collagen content. In addition, NIR-determined water correlated with short-term modulus and proteoglycan content (R = -0.40 and -0.31, respectively), and a multivariate model with NIR data was able to predict short-term modulus within 15% error.

CONCLUSIONS

The properties of tissues from LWB regions differ from HWB tissues and can be determined non-destructively by infrared fiber optic spectroscopy. Clinicians may be able to use this modality to assess AC prior to harvesting osteochondral grafts for focal defect repair.

Fluid imbibition at the bone-cartilage interface is associated with need for early chondroplasty following osteochondral allografting of the knee

PURPOSE

To determine the clinical significance of fluid imbibition at the bone-cartilage interface seen on postoperative MRI scans after osteochondral grafting of chondral lesions of the knee.

METHODS

Retrospective review of patients enrolled in a prospective cartilage repair registry. Included patients underwent osteochondral autografting or allografting of the knee, had minimum one year of clinical follow-up, and underwent at least two postoperative MRI scans. The primary outcome was reoperation for arthroscopic debridement and chondroplasty or graft revision. Secondary outcomes included the radiographic fate of fluid imbibition.

RESULTS

A total of 48 knees in 46 patients were analyzed, with mean 39 months clinical follow-up. Nine patients (19%) had fluid imbibition on at least one postoperative MRI scan, all of whom received allograft. Of these, two (22%) required eventual graft revision, four (45%) underwent arthroscopic chondroplasty but did not require revision, and three (33%) did not require any additional surgery by final follow-up. No demographic or surgical variable was associated with the presence of fluid imbibition. Fluid imbibition was significantly associated with need for chondroplasty (p = 0.05), but not graft revision.

CONCLUSIONS

Fluid imbibition on postoperative MRI following osteochondral allografting of the knee is associated with the need for arthroscopic chondroplasty, but should not be interpreted as a sign of a failing graft.

LEVEL OF EVIDENCE

Level IV, Case Series.

Clinical Outcomes of Revision Osteochondral Allograft Transplantation

PURPOSE

To assess the survivorship, clinical outcomes, and radiographic outcomes of patients who have undergone revision osteochondral allograft (OCA) to the knee in a retrospective case series.

METHODS

Nine patients who underwent revision OCA by the senior author between January 2003 and December 2015 with a minimum follow up of 2 years were reviewed retrospectively. Patients completed patient-reported outcome surveys containing the visual analog scale, the International Knee Documentation Committee, the Knee injury and Osteoarthritis Outcome Score, Lysholm score, and the Short-Form 12. Radiographic analysis included anteroposterior view graded via the Kellgren and Lawrence scale. Complications and reoperations were analyzed, with failure defined as conversion to arthroplasty. (Institutional review board 15050301.) RESULTS: One of 10 consecutive patients was lost to follow up, for an overall follow-up rate of 90% (5 males, 4 females); mean follow up, 4.53 ± 3.17 years. The median patient age at the time of revision OCA was 33 years (interquartile range [IQR], 8.6), the median defect size was 4.0 cm² (IQR, 0), and the median time from index OCA to revision OCA was 2.9 years (IQR, 1.9). Five patients (50%) underwent subsequent surgery at a median of 1.92 years (IQR, 7.25), with 1 progressing to arthroplasty at 23 months after revision OCA, for an overall failure rate of 11%. There were no significant differences in any of the patient-reported outcome assessments compared with prerevision OCA (postindex OCA) values at final follow up (P > .05 for all). Similarly, there were no significant differences in Kellgren and Lawrence score before and after surgery (P = .1).

CONCLUSIONS

At a mean 4.5 years following revision OCA, there was an 89% graft survivorship rate in a series of 9 patients, with no statistical changes in the radiographic progression of arthritis.

LEVEL OF EVIDENCE

Level IV, case series.

Surgical and tissue engineering strategies for articular cartilage and meniscus repair

Injuries to articular cartilage and menisci can lead to cartilage degeneration that ultimately results in arthritis. Different forms of arthritis affect ~50 million people in the USA alone, and it is therefore crucial to identify methods that will halt or slow the progression to arthritis, starting with the initiating events of cartilage and meniscus defects. The surgical approaches in current use have a limited capacity for tissue regeneration and yield only short-term relief of symptoms. Tissue engineering approaches are emerging as alternatives to current surgical methods for cartilage and meniscus repair. Several cell-based and tissue-engineered products are currently in clinical trials for cartilage lesions and meniscal tears, opening new avenues for cartilage and meniscus regeneration. This Review provides a summary of surgical techniques, including tissue-engineered products, that are currently in clinical use, as well as a discussion of state-of-the-art tissue engineering strategies and technologies that are being developed for use in articular cartilage and meniscus repair and regeneration. The obstacles to clinical translation of these strategies are also included to inform the development of innovative tissue engineering approaches.

Anatomic Risk Factors for Focal Cartilage Lesions in the Patella and Trochlea: A Case-Control Study

BACKGROUND

Focal cartilage lesions in the patellofemoral (PF) joint are common. Several studies correlated PF risk factors with PF instability, anterior knee pain, and PF arthritis; however, there is a lack of evidence correlating those factors to PF focal cartilage lesions.

PURPOSE

To evaluate the influence of the anatomic PF risk factors in patients with isolated focal PF cartilage lesions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Patients with isolated PF focal cartilage lesions were included in the cartilage lesion group, and patients with other pathologies and normal PF cartilage were included in the control group. Multiple PF risk factors were accessed on magnetic resonance imaging scans: patellar morphology (patellar width, patellar thickness, and patellar angle), trochlear morphology (trochlear sulcus angle, lateral condyle index, and trochlear sulcus depth), patellar height (Insall-Salvati ratio and Caton-Deschamps index), axial patellar positioning (patellar tilt, angle of Fulkerson), and quadriceps vector (tibial tuberosity-trochlear groove distance).

RESULTS

A total of 135 patients were included in the cartilage lesion group and 100 in the control group. As compared with the control group, the cartilage lesion group had a higher sulcus angle (P = .0007), lower trochlear sulcus depth (P < .0001), lower angle of Fulkerson (P < .0001), lower patellar width (P = .0003), and higher Insall-Salvati ratio (P < .0001). From the patients in the cartilage lesion group, 36% had trochlear dysplasia; 27.6%, patella alta; and 24.7%, abnormal patellar tilt. These parameters were more frequent in the cartilage lesion group (P < .0001). Trochlear lesions were more frequent in men, presented at an older age, and had fewer associated anatomic risk factors. Patellar lesions, conversely, were more frequent in women, presented at younger age, and were more closely associated with anatomic risk factors.

CONCLUSION

PF anatomic abnormalities are significantly more common in patients with full-thickness PF cartilage lesions. Trochlear dysplasia, patella alta, and excessive lateral patellar tilt are the most common correlated factors, especially in patellar lesions.

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.

Metabolic responses of osteochondral allografts to re-warming

Symptomatic chondral and osteochondral defects affect a large and growing number of patients. A safe and effective surgical treatment for large articular defects is osteochondral allograft (OCA) transplantation. One of the major causes of failure for OCA transplantation is loss of essential chondrocyte viability during the preservation and storage period. It is also possible that metabolic responses of the OCA when transitioning from storage temperature to body temperature may contribute to mechanisms causing failure. The present study was designed to compare MOPS^SM -preserved OCAs to those stored using the current standard of care (SOC) method with respect to metabolic responses when rewarmed for transplantation to and maintenance at body temperature (37°C). It was theorized that grafts stored using the MOPS^SM protocol would maintain significantly higher chondrocyte viability and produce significantly lower levels of inflammatory mediators and degradative enzymes, and significantly higher levels of chemokines compared to grafts stored using the SOC protocol. Left over SOC and MOPS^SM -stored OCA tissues were collected after surgery, and cartilage explants were cultured for 6 days. Media was analyzed for biomarkers using commercially available assays. Cartilage from SOC grafts released significantly higher levels of PGE2, MMP-1, MMP-2, and MMP-13, and significantly lower levels of IL-8 and Gro-α, compared to cartilage from MOPS^SM -stored grafts. Clinical significance: These data suggest that OCAs stored using the MOPS^SM protocol have potentially less detrimental initial inflammatory and degradative responses to re-warming for transplantation compared to OCAs stored using the current tissue bank protocols. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1530-1536, 2019.

Decreased Graft Thickness Is Associated With Subchondral Cyst Formation After Osteochondral Allograft Transplantation in the Knee

BACKGROUND

Subchondral changes, specifically cyst formation, are a known finding after osteochondral allograft (OCA) transplantation.

PURPOSE/HYPOTHESIS

The purpose was to determine potential predictive associations between preoperative patient characteristics or OCA morphology and postoperative OCA appearance as assessed by the osteochondral allograft magnetic resonance imaging scoring system (OCAMRISS) at 6-month follow-up. It was hypothesized that preoperative patient factors or OCA morphology is associated with postoperative OCAMRISS scores.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

This study evaluated 74 OCAs that were implanted in the femoral condyles of 63 patients for the treatment of symptomatic osteochondral defects in the knee. Postoperative magnetic resonance imaging was obtained at a mean ± SD follow-up of 5.5 ± 1.0 months. A musculoskeletal radiologist scored all grafts according to the OCAMRISS. Point biserial correlation, Mann-Whitney U test, Fisher exact test, and chi-square test were used to distinguish associations between OCAMRISS subscales and age, sex, smoker status, body mass index, previous surgery, concomitant surgery, bone marrow augmentation, graft location, graft size, and bony graft thickness.

RESULTS

OCA bony thickness showed significant correlation with cystic changes at the graft-host junction (P = .019). Grafts with cystic formation were significantly thinner than grafts without cystic changes (P = .008). The odds ratio for grafts with <5-mm bony thickness demonstrating cystic changes was 4.9 (95% CI, 1.5-16.1; P = .009). Bony graft thickness was not associated with graft integration, but 40% of grafts with a bony thickness >9 mm presented with a residual osseous cleft, as opposed to 11.3% of thinner grafts (P = .1). The augmentation with bone marrow aspirate did not affect osseous graft integration or subchondral cystic formation (P = .375 and P = .458, respectively).

CONCLUSION

Osteochondral allograft thickness is associated with subchondral cyst formation at short-term follow-up. Thin grafts demonstrate a substantially increased risk of developing subchondral cysts at the graft-host junction after OCA transplantation. Conversely, thicker grafts may negatively affect osseous graft integration. Hence, surgeons should be aware of the potential pitfalls of transplanting thin or thick grafts regarding cystic formation and delay of osseous integration after cartilage resurfacing.

Long-Term Results of Treating Large Posttraumatic Tibial Plateau Lesions with Fresh Osteochondral Allograft Transplantation

BACKGROUND

The use of fresh osteochondral allograft (FOCA) transplantation is a treatment option for large posttraumatic tibial osteochondral defects in young, high-demand patients. We aimed to assess the long-term outcomes of this procedure and factors impacting graft survivorship.

METHODS

Evaluated were patients with a posttraumatic tibial plateau defect of >3 cm in diameter and >1 cm in depth who were treated with use of a FOCA, with or without a realignment osteotomy, before September 2007. The primary outcome was survivorship according to Kaplan-Meier analysis, with conversion to arthroplasty or another allograft procedure as the end point. The secondary outcome was the functional outcome of knees with a surviving FOCA, as assessed using the modified Hospital for Special Surgery (mHSS) scoring system. Multivariate Cox regression analysis of the role of potential variables was performed for both outcomes.

RESULTS

Included were 113 patients (67 female) with a mean age at the time of the index surgery of 43 years (range, 24 to 72 years) and a mean follow-up of 13.8 years (range, 1.7 to 34 years). Forty-eight conversions to arthroplasty or another FOCA procedure had been performed at a mean of 11.6 years (range, 1.7 to 34 years) after the index surgery. The remaining 65 patients had a mean follow-up of 15.5 years (range, 4.3 to 31.7 years). The mean mHSS score among those with a surviving FOCA was 85.5 (range, 56 to 100) at the most recent follow-up, which was significantly higher than the preoperative value of 69 (range, 48 to 85) (p < 0.001). Graft survivorship was 90% at 5 years, 79% at 10 years, 64% at 15 years, and 47% at 20 years. Complications included infection (1.8%), nonunion (0.9%), and knee pain from hardware (8.8%). Multivariate analysis revealed that older age at the time of surgery, involvement of the medial plateau, and a higher number of previous surgeries were inversely associated with graft survivorship. Having a Workers' Compensation file was associated with less improvement in the mHSS score, and the score tended to decline over time for knees with a surviving FOCA.

CONCLUSIONS

FOCA transplantation is a viable option for posttraumatic tibial osteochondral defects, with satisfactory survivorship and functional outcome. Although approximately half of the patients in our study demonstrated graft failure by 20 years, FOCA was an excellent option that delayed the need for arthroplasty. Older patients, those with medial defects, and those with multiple previous surgeries had a less favorable prognosis.

LEVEL OF EVIDENCE

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

Outcomes Associated with Return to Sports Following Osteochondral Allograft Transplant in the Knee: a Scoping Review

PURPOSE OF REVIEW

The purposes of this review were to report the currently validated outcomes for OCA transplant patients, discuss the benefits and challenges associated with "return to sports" as an outcome measure, and summarize the currently available data on patients' ability to return to sports after OCA transplant.

RECENT FINDINGS

College athletes may take less time than professionals to return to basketball, but there are many factors that can influence this timeframe. Player productivity is decreased ~ 40% and future career length is only 1 to 2 years following return to play. When evaluating all OCA transplant patients, 75-88% of patients return to sport and 38-80% return to their previous level of play at approximately 8-10 months following surgery. Overall graft failure rates are low (0-9.4%) but are based on limited short- to medium-term data. Data on the return to professional and college sports after OCA transplant is limited. Surgeons should consider collecting patient outcomes across multiple domains and contributing data to aggregate databases to allow for better quality outcome data to be reported.

Osteochondral Allograft Transplantation of the Femoral Condyle Utilizing a Thin Plug Graft Technique

BACKGROUND

Previous studies showed clinical benefit and durable results of osteochondral allograft (OCA) transplantation for the treatment of femoral condyle lesions. However, the majority of these studies are difficult to interpret owing to the mixed results of different techniques and anatomic locations.

PURPOSE

To evaluate the outcome of OCA transplantation with thin plug grafts for treatment of isolated femoral condyle osteochondral lesions.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This study included 187 patients (200 knees) who underwent OCA transplantation for isolated osteochondral lesions on the femoral condyle between 1999 and 2014. For all cases, a thin plug technique was used with commercially available surgical instruments and the minimum amount of bone necessary for fixation. Evaluation included International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, and patient satisfaction. Frequency and type of further surgery were assessed. Failure of the allograft was defined as further surgery involving removal of the allograft.

RESULTS

Mean follow-up was 6.7 years (range, 1.9-16.5 years). The mean age of patients at the time of surgery was 31 years, and 63% were male. The medial femoral condyle was affected in 69% of knees. A single thin plug graft was used in 145 knees (72.5%), and 2 grafts were used in 55 knees (27.5%). Mean allograft area was 6.3 cm², and graft thickness was 6.5 mm (cartilage and bone combined). Further surgery was required for 52 knees (26%), of which 16 (8% of entire cohort) were defined as allograft failures (4 OCA revisions, 1 arthrosurface, 6 unicompartmental knee arthroplasties, and 5 total knee arthroplasties). Median time to failure was 4.9 years. Survivorship of the allograft was 95.6% at 5 years and 91.2% at 10 years. Among patients with grafts remaining in situ at latest follow-up, clinically meaningful improvement in pain, function, and quality of life was reported. Satisfaction was reported by 89% of patients.

CONCLUSION

OCA transplantation with a thin plug graft technique is a valuable procedure for the treatment of femoral condyle osteochondral lesions, resulting in significant improvement in clinical scores, high patient satisfaction, and low reoperation and clinical failure rates.

Return to Sport and Sports-Specific Outcomes After Osteochondral Allograft Transplantation in the Knee: A Systematic Review of Studies With at Least 2 Years' Mean Follow-Up

PURPOSE

To report current data on return-to-sport rates and sports-specific patient-reported outcomes after osteochondral allograft (OCA) transplantation for cartilage defects of the knee.

METHODS

We performed a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines that included studies from 1975 to 2018 with a minimum 2-year mean follow-up that reported return-to-sport rates or sports-specific patient-reported outcomes. Outcomes, reoperations, and complications were provided in table format, and a subjective analysis was performed.

RESULTS

This review included 13 studies with 772 patients who underwent OCA transplantation at a mean of 24 to 91 months' follow-up. The return-to-sport rate ranged from 75% to 82%. For patient-reported outcomes, the Knee Injury and Osteoarthritis Score Sport increased in 4 studies, the Tegner activity scale score increased in 3 studies but decreased in 1, and the Marx activity scale score increased in 1 study but decreased in 2. Studies reporting improvements in the Cincinnati Knee Score and Knee Injury and Osteoarthritis Score Sport reached the minimal clinically important difference. The reoperation rate was high (ranging from 34% to 53% in more than half of studies), with reoperations primarily performed for loose body removal or debridement.

CONCLUSIONS

This systematic review of 13 studies suggests that OCA transplantation for cartilage defects allows most athletes to return to sport (range, 75%-82%). Most studies reported improvements in sports-specific patient-reported outcomes at follow-up and reached the minimal clinically important difference. However, the reoperation rate was high in several studies, with a large percentage of patients requiring loose body removal or debridement. The long-term survival of the allografts is largely unknown, but this study suggests OCA transplantation consistently improves function in athletes with chondral injuries.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

Analysis of Defect Size and Ratio to Condylar Size With Respect to Outcomes After Isolated Osteochondral Allograft Transplantation

BACKGROUND

Osteochondral allograft transplantation (OCA) is a successful knee joint preservation technique; however, the effects of defect size and defect size:condyle ratio (DSCR) are poorly understood.

PURPOSE

To quantify clinical outcomes of isolated OCA of the knee based on defect size and DSCR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data from patients who underwent OCA of the knee without major concomitant procedures by a single surgeon were analyzed at a minimum follow-up of 2 years. Osteochondral defect size was measured intraoperatively, and femoral condyle size was measured with preoperative imaging. Patient-reported outcomes, reoperations, and survival rates were analyzed per defect size and DSCR, comparing males and females and patients <40 and ≥40 years old.

RESULTS

Sixty-eight patients were included, of whom 57% were male (mean ± SD: age, 34.5 ± 10.3 years; follow-up, 5.2 ± 2.6 years). Mean osteochondral defect size and DSCR were 3.48 ± 1.72 cm² and 0.2 ± 0.1, respectively. Defect size was larger among males as compared with females (3.97 ± 1.71 cm² vs 2.81 ± 1.16 cm², P = .005), while DSCRs were not significantly different between sexes ( P = .609). The cohort as a whole demonstrated improvements in the following scores: Lysholm, International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, and 12-Item Short Form Health Survey Physical ( P < .05). There were 27 reoperations (39.7%) at a mean of 2.5 ± 1.92 years and 8 failures (11.8%) at a mean of 2.62 ± 1.3 years. Mean DCSR was higher among patients with graft failure (0.26 ± 0.20 vs 0.19 ± 0.07, P = .049). After stratification by age, failures among patients ≥40 years old were associated with a larger defect size (mean 5.37 ± 3.50 cm² vs 3.22 ± 1.32 cm², P = .03) and higher DSCR (mean 0.30 ± 0.25 vs 0.19 ± 0.06, P = .05) when compared with nonfailures. Failures among patients <40 years old were not significantly associated with defect size or DSCR ( P > .05) as compared with nonfailures.

CONCLUSION

Patients undergoing isolated OCA transplantation demonstrated significant clinical improvements and a graft survival of 88.2% at 5.2 years. Failures overall were associated with a larger DSCR, and failures among patients ≥40 years old with a larger DSCR and larger defect size. Increasing defect size among males was positively correlated with some improved outcomes, although this was not maintained in analysis of the DSCR, suggesting similar prognosis after OCA regardless of sex.

CLINICAL RELEVANCE

Failed osteochondral allografts are associated with larger defect sizes and defect:condyle ratios in this study, providing additional information to surgeons for appropriate patient consultation.

Osteochondral Allograft Transplantation of the Knee in Patients with an Elevated Body Mass Index

OBJECTIVE

To characterize the graft survivorship and clinical outcomes of osteochondral allograft transplantation (OCA) of the knee in patients with an elevated body mass index (BMI).

DESIGN

Prospective data on 38 consecutive patients with a BMI ≥30 kg/m² treated with OCA from 2000 to 2015 were reviewed. Complications, reoperations, and patient responses to validated outcome measures were examined. Failures were defined by any removal/revision of the allograft or conversion to arthroplasty.

RESULTS

Thirty-one knees in 31 patients (mean age, 35.4 years [range, 17-61 years]; 87% male) met the inclusion criteria. Mean BMI was 32.9 kg/m² (range, 30-39 kg/m²). Mean chondral defect size was 6.4 cm² (range, 1.0-15.3 cm²). Prior to OCA, 23 patients (74%) had undergone previous surgery to the ipsilateral knee. Mean duration of follow-up was 4.1 years (range, 2-11 years). After OCA, 5 knees (13%) underwent conversion to unicompartmental (1) or total (4) knee arthroplasty. Two- and 5-year graft survivorship were 87% and 83%, respectively. At final follow-up, clinically significant improvements were noted in the pain (49.3-72.6) and physical functioning (52.9-81.3) subscales of the Short Form-36 ( P ≤ 0.001), International Knee Documentation Committee subjective form (43.5-67.0; P = 0.002), Knee Outcome Survey-Activities of Daily Living (58.2-80.4; P = 0.002), and overall condition subscale of the Cincinnati Knee Rating System (4.7-6.9; P = 0.046).

CONCLUSIONS

OCA can be a successful midterm treatment option for focal cartilage defects of the knee in select patients with a BMI ≥30 kg/m².

Enzymatically Cross-Linked Silk Fibroin-Based Hierarchical Scaffolds for Osteochondral Regeneration

Osteochondral (OC) regeneration faces several limitations in orthopedic surgery, owing to the complexity of the OC tissue that simultaneously entails the restoration of articular cartilage and subchondral bone diseases. In this study, novel biofunctional hierarchical scaffolds composed of a horseradish peroxidase (HRP)-cross-linked silk fibroin (SF) cartilage-like layer (HRP-SF layer) fully integrated into a HRP-SF/ZnSr-doped β-tricalcium phosphate (β-TCP) subchondral bone-like layer (HRP-SF/dTCP layer) were proposed as a promising strategy for OC tissue regeneration. For comparative purposes, a similar bilayered structure produced with no ion incorporation (HRP-SF/TCP layer) was used. A homogeneous porosity distribution was achieved throughout the scaffolds, as shown by micro-computed tomography analysis. The ion-doped bilayered scaffolds presented a wet compressive modulus (226.56 ± 60.34 kPa) and dynamic mechanical properties (ranging from 403.56 ± 111.62 to 593.56 ± 206.90 kPa) superior to that of the control bilayered scaffolds (189.18 ± 90.80 kPa and ranging from 262.72 ± 59.92 to 347.68 ± 93.37 kPa, respectively). Apatite crystal formation, after immersion in simulated body fluid (SBF), was observed in the subchondral bone-like layers for the scaffolds incorporating TCP powders. Human osteoblasts (hOBs) and human articular chondrocytes (hACs) were co-cultured onto the bilayered structures and monocultured in the respective cartilage and subchondral bone half of the partitioned scaffolds. Both cell types showed good adhesion and proliferation in the scaffold compartments, as well as adequate integration of the interface regions. Osteoblasts produced a mineralized extracellular matrix (ECM) in the subchondral bone-like layers, and chondrocytes showed GAG deposition. The gene expression profile was different in the distinct zones of the bilayered constructs, and the intermediate regions showed pre-hypertrophic chondrocyte gene expression, especially on the BdTCP constructs. Immunofluorescence analysis supported these observations. This study showed that the proposed bilayered scaffolds allowed a specific stimulation of the chondrogenic and osteogenic cells in the co-culture system together with the formation of an osteochondral-like tissue interface. Hence, the structural adaptability, suitable mechanical properties, and biological performance of the hierarchical scaffolds make these constructs a desired strategy for OC defect regeneration.

Management of Chondral Lesions of the Knee: Analysis of Trends and Short-Term Complications Using the National Surgical Quality Improvement Program Database

PURPOSE

To provide updated surgical trends of cartilage procedures differentiated by the classic groups of palliative, repair, and restorative modalities.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2010-2016 for the following cartilage procedures: chondroplasty, microfracture, arthroscopic osteochondral autograft or allograft transplantation, open osteochondral autograft or allograft transplantation, and autologous chondrocyte implantation. Demographic variables and short-term (30-day) complications were analyzed with 1-way analysis of variance and post hoc analysis. Linear regression analysis was performed to analyze trends over time.

RESULTS

A total of 15,609 procedures performed between 2010 and 2016 were analyzed. On average, 342.2 ± 27.9 cartilage procedures were performed per 100,000 operations. There was a linear increase in the management of overall cartilage procedures per 100,000 operations (P = .002). There were also linear increases in arthroscopic osteochondral autograft transplantation, arthroscopic osteochondral allograft transplantation, open osteochondral autograft transplantation, open osteochondral allograft transplantation, and autologous chondrocyte implantation (P < .001, P = .037, P = .001, P = .006, and P = .002, respectively). Meniscectomy was the most frequently performed concomitant procedure (9.7%-64.2% of cases). Chondroplasty and microfracture showed no change in frequency over time (P = .140 and P = .720, respectively). The overall complication rate was 2.1% for chondroplasty, 1.4% for microfracture, 1.8% for arthroscopic osteochondral autograft transplantation, 1.0% for arthroscopic osteochondral allograft transplantation, 1.4% for open osteochondral autograft transplantation, 1.1% for open osteochondral allograft transplantation, and 0.75% for autologous chondrocyte implantation. Deep vein thrombosis was the most common complication, occurring in 0.4% to 1.0% of cases. No statistically significant difference was found in complication rates between procedures (P = .105).

CONCLUSIONS

Cartilage restoration is becoming an increasingly popular modality to address chondral defects. Minimal complication rates suggest that these procedures may be safely performed concomitantly with other interventions.

LEVEL OF EVIDENCE

Level IV, retrospective database analysis.

Clinically Meaningful Improvement After Treatment of Cartilage Defects of the Knee With Osteochondral Grafts

BACKGROUND

Mosaicplasty and fresh osteochondral allograft transplantation (OCA) are popular cartilage restoration techniques that involve the single-stage implantation of viable, mature hyaline cartilage-bone dowels into chondral lesions of the knee. Recently, there has been greater focus on what represents a clinically relevant change in outcomes reporting, and commonly applied metrics for measuring clinical significance include the minimal clinically important difference (MCID) and substantial clinical benefit (SCB).

PURPOSE

To define the MCID and SCB after mosaicplasty or OCA for the International Knee Documentation Committee (IKDC) subjective form and Knee Outcome Survey-Activities of Daily Living (KOS-ADL) and to determine patient factors that are predictive of achieving the MCID and SCB after mosaicplasty or OCA.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

An institutional cartilage registry was reviewed to identify patients who underwent mosaicplasty or OCA. The decision to perform either mosaicplasty or OCA was generally based on chondral defect size. The IKDC and KOS-ADL were administered preoperatively and at a minimum of 2 years postoperatively. Patient responses to the outcome measures were aggregated, and the MCID and SCB of these outcome scores were calculated with anchor-based methods. Multivariate analysis adjusted for age and sex was performed to identify patient factors predictive of achieving the MCID and SCB.

RESULTS

Of the 372 eligible patients, 151 (41%) were lost to follow-up, 46 (12%) had incomplete preoperative outcome scores and 2 were treated with OCA of the tibia and therefore excluded. In total, 173 knees were analyzed (n = 173 patients; mean age, 33.0 years; 37% female). Seventy-five (43%) and 98 (57%) knees were treated with mosaicplasty and OCA, respectively. The mean ± SD MCIDs for the IKDC and KOS-ADL were 17 ± 3.9 and 10 ± 3.7, respectively. The SCBs for the IKDC and KOS-ADL were 30 ± 6.9 and 17 ± 3.9, respectively. Univariate analysis demonstrated no association between procedure (mosaicplasty or OCA) and likelihood of achieving the MCID or SCB. In the multivariate analysis, lower preoperative IKDC and KOS-ADL scores, higher preoperative Marx Activity Rating Scale scores, lower preoperative 36-Item Short Form Health Survey pain scores, and a history of ≤1 prior ipsilateral knee surgical procedure were predictive of achieving the MCID and/or SCB.

CONCLUSION

These values can be used to define a clinically meaningful improvement for future outcome studies. For surgeons considering mosaicplasty or OCA for their patients, these results can help guide clinical decision making and manage patient expectations before surgery.

The cost-effectiveness of osteochondral allograft transplantation in the knee

PURPOSE

Osteochondral allografts (OCA) consist of a layer of hyaline cartilage and a layer of underlying bone. They are used to repair combined defects of articular cartilage and bone. Such defects often occur in people far too young to have knee arthroplasty, for whom the main alternative to OCA is conservative symptomatic care, which will not prevent development of osteoarthritis. The aim of this report was to assess the cost-effectiveness of osteochondral allograft transplantation in the knee.

METHODS

Systematic review of evidence on clinical effectiveness and economic modelling.

RESULTS

The evidence on osteochondral allograft transplantation comes from observational studies, but often based on good quality prospective registries of all patients having such surgery. Without controlled trials, it was necessary to use historical cohorts to assess the effect of osteochondral grafts. There is good evidence that OCA are clinically effective with a high graft survival rate over 20 years. If an OCA graft fails, there is some evidence that revision with a second OCA is also effective, though less so than primary OCA. Economic modelling showed that osteochondral allograft transplantation was highly cost-effective, with costs per quality adjusted life year much lower than many other treatments considered cost effective.

CONCLUSIONS

Osteochondral allograft transplantation appears highly cost-effective though the cost per quality adjusted life year varies according to the widely varying costs of allografts. Based on one small study, revision OCA also appears very cost-effective, but more evidence is needed.

LEVEL OF EVIDENCE

II.

Mental Health Has No Predictive Association With Self-Assessed Knee Outcome Scores in Patients After Osteochondral Allograft Transplantation of the Knee

Background:

Patient-reported outcome (PRO) measures are progressively utilized as evaluation tools in preoperative and postoperative assessments in orthopaedic practice. Identifying the potential utility of psychosocial factors to predict patient-reported pain and functional outcomes is of increasing interest to determine which patients will derive the greatest benefit from surgical treatment.

Purpose/Hypothesis:

The purpose of this study was to determine potential predictive associations between the preoperative 12-Item Short Form Health Survey Mental Component Summary (SF-12 MCS) score, patient characteristics or osteochondral allograft (OCA) morphology, and PROs in patients who underwent OCA transplantation. We hypothesized that poor preoperative mental health is associated with diminished PROs at final follow-up.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 67 patients with a mean follow-up of 2.7 ± 1.0 years (range, 2-6 years) with complete preoperative and at least 24-month postoperative SF-12 MCS, Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner, Lysholm, and International Knee Documentation Committee (IKDC) scores were included in this study. Pearson correlation coefficients and linear regression models were used to distinguish associations between age, sex, smoking status, body mass index, workers’ compensation, previous surgery, concomitant surgery, number of grafts, defect location, total graft size, SF-12 MCS score, and postoperative PRO scores as well as their improvement from baseline (delta).

Results:

The SF-12 MCS showed significant correlation with the KOOS Activities of Daily Living subscale (P = .015), KOOS Sport/Recreation subscale (P = .024), and IKDC (P = .039). In the multivariable linear regression models, the SF-12 MCS had no predictive association with any PRO measure. Patient sex contributed significantly to the final regression models of the KOOS Sport/Recreation (P = .042), Tegner score (P = .024), and Lysholm score (P = .031). The SF-12 MCS showed no bivariate correlation with changes in any PRO score (delta) (P > .05).

Conclusion:

Preoperative mental health status did not predict perceived functional outcomes as assessed by PRO measures at final follow-up. Female sex was negatively correlated with KOOS Sport/Recreation, Tegner, and Lysholm scores.

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

BACKGROUND

Fresh osteochondral allograft transplantation is an appealing option to address a failed cartilage repair surgical procedure, given the ability to treat large lesions and to address the subchondral osseous changes commonly seen in the revision setting. We hypothesized that osteochondral allograft transplantation after failed cartilage repair would result in low failure rates and improved function and that improved graft incorporation on postoperative magnetic resonance imaging (MRI) would correlate with a superior clinical outcome.

METHODS

A retrospective review of prospectively collected data was used to identify 43 patients treated with fresh osteochondral allograft transplantation after a previous cartilage repair surgical procedure and having a minimum follow-up of 2 years. Clinical outcomes were evaluated using the Short Form-36 (SF-36) score, International Knee Documentation Committee (IKDC) Subjective Knee Score, Marx Activity Scale, Knee Outcome Survey-Activities of Daily Living (KOS-ADL) Questionnaire, Cincinnati Sports Activity Score, and Cincinnati Overall Symptom Assessment. Postoperative MRI scans were obtained at a mean time of 19.7 months and were independently reviewed by a musculoskeletal radiologist using the Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

At a mean 3.5-year follow-up after osteochondral allograft transplantation, significant improvements (p < 0.05) in SF-36 Physical Function, SF-36 Pain, KOS-ADL, IKDC Subjective Knee Score, and Cincinnati Overall Symptom Assessment were seen. Over 90% of grafts remained in situ at the time of the latest follow-up, although 17 knees (40%) underwent reoperation, the majority for arthroscopic debridement or manipulation for stiffness. Body mass index (BMI) of >30 kg/m was associated with worse clinical outcomes. The mean total OCAMRISS score demonstrated poorer allograft integration in patients with graft failure, but the total score did not meaningfully correlate with clinical outcome scores. However, better individual articular cartilage appearance and osseous integration subscores were associated with better clinical outcome scores.

CONCLUSIONS

Significant improvements in pain and function were seen following fresh osteochondral allograft transplantation after failed cartilage repair, with an overall graft survival rate of >90%. Patients with greater bone and cartilage incorporation on MRI had superior clinical outcomes, although persistent osseous edema was frequently seen. We concluded that osteochondral allograft transplantation is an effective salvage treatment after failed cartilage repair and recommend further evaluation of techniques to optimize graft integration.

LEVEL OF EVIDENCE

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

Efficacy of Fresh Osteochondral Allograft Transplantation in the Knee for Adults 40 Years and Older

Background:

Osteochondral allograft (OCA) transplantation has become a standard therapy for cartilage restoration in young patients.

Purpose:

To determine the efficacy of fresh OCA transplantation for focal cartilage lesions in patients aged ≥40 years compared with a group of patients aged ≤39 years.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A database was used to identify patients who underwent fresh OCA transplantation in the knee in a single-surgeon practice over a 10-year period and who completed baseline patient-reported outcome (PRO) questionnaires, including the International Knee Documentation Committee (IKDC); Knee injury and Osteoarthritis Outcome Score (KOOS) subscales of Pain, Symptoms, Activities of Daily Living, Quality of Life (QOL), and Sports & Recreation; and Veterans RAND 12-Item Health Survey (VR-12). Patients who completed the same PRO measures at a minimum 12-month follow-up were categorized into 2 groups based on age at surgery and were observed longitudinally. Mixed-model regression was used to predict longitudinal growth curves for each PRO score while controlling for confounding patient and surgical variables.

Results:

The study group consisted of 38 patients with a mean age of 52.32 years (range, 40-69 years) and mean final follow-up of 44.47 ± 24.32 months. The control group consisted of 42 patients with a mean age of 27.19 years (range, 15-39 years) and mean final follow-up of 33.75 ± 19.53 months. A statistically significant improvement from baseline to final follow-up was seen for the IKDC score and all 5 KOOS subscores in both the study and the control groups (P < .01 in 10 of 12 comparisons and P < .05 for the other 2 comparisons). Maximum improvements were seen in the KOOS QOL and Sports & Recreation subscores for both groups. There was no statistically significant difference between groups in the change from baseline to final follow-up or in differences at any time point in model-based longitudinal projections for any PRO score through 5 years.

Conclusion:

There was a significant improvement of outcomes for both groups, with no statistically significant difference between groups over longitudinal follow-up. The efficacy of fresh OCA transplantation in adults aged ≥40 years with a focal chondral lesion and without osteoarthritis is similar to that of younger adults, and benefits are greatest for the KOOS QOL and Sports & Recreation subscales, which reflect functional outcomes.

Preservation of Knee Articular Cartilage

Hyaline articular cartilage is critical for the normal functioning of the knee joint. Untreated focal cartilage defects have the potential to rapidly progress to diffuse osteoarthritis. Over the last several decades, a variety of interventions aiming at preserving articular cartilage and preventing osteoarthritis have been investigated. Reparative cartilage procedures, such as microfracture, penetrate the subchondral bone plate in effort to fill focal cartilage defects with marrow elements and stimulate fibrocartilaginous repair. In contrast, restorative cartilage procedures aim to replace the defective articular surface with autologous or allogeneic hyaline cartilage. This review focuses on the preservation of articular cartilage, and discusses the current reparative and restorative surgical techniques available for treating focal cartilage defects.

Clinical Outcomes of Multifocal Osteochondral Allograft Transplantation of the Knee: An Analysis of Overlapping Grafts and Multifocal Lesions

BACKGROUND

There is a paucity of literature regarding the outcomes of adjacent-plug osteochondral allograft transplantation (OCA) for irregular or ovoid lesions and multifocal OCA for multicompartmental, focal lesions.

PURPOSE

To quantify the survival of multiplug OCA for larger, high-grade chondral lesions with the "snowman" technique versus that of multicompartmental or bipolar OCA.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All patients who underwent primary, multiplug OCA for large unicondylar, multicompartmental (eg, bipolar patellofemoral and condylar, bicondylar), or bipolar chondral defects (ie, patellofemoral) with a minimum 2-year follow-up by a single surgeon from April 1, 2003, to April 1, 2015, were analyzed. Failure was defined as revision OCA, conversion to arthroplasty, or gross appearance of graft degeneration on second-look arthroscopic surgery.

RESULTS

Twenty-six patients (28 knees) were identified, with 22 patients (24 knees; 50% female; mean age, 31.9 ± 9.1 years) having at least 2-year clinical follow-up (85.7%). Nine patients (9 knees) underwent isolated, condylar OCA with the snowman technique and had a mean follow-up of 7.4 ± 3.6 years (range, 1.38-11.14 years), while 13 additional patients (15 knees) underwent multifocal OCA and had a mean follow-up of 6.4 ± 3.9 years (range, 2.07-12.38 years). Reoperations were common, with 44.4% (n = 4) of the snowman group and 20.0% (n = 3) of the multifocal group undergoing at least 1 reoperation. There were 3 failures (33.3%) in the snowman group at a mean 7.7 ± 5.5 years and 1 failure (6.7%) in the multifocal group at 4.5 ± 0.0 years, with all undergoing secondary total knee arthroplasty. Patients who underwent snowman OCA demonstrated significant postoperative improvement in the Knee injury and Osteoarthritis Outcome Score (KOOS) pain subscore and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) overall score ( P < .05 for both). Patients who underwent multifocal OCA demonstrated significant improvement in the International Knee Documentation Committee score; KOOS symptoms, activities of daily living, sport, and quality of life subscores; WOMAC stiffness, function, and overall subscores; and 12-Item Short Form Health Survey physical component summary score ( P < .05 for all).

CONCLUSION

Patients who underwent unicondylar, multiplug OCA using the snowman technique demonstrated inferior clinical outcomes, higher reoperation rates, and greater failure rates than those who underwent isolated single-graft transplantation. By contrast, multifocal OCA may be a viable knee preservation technique for young, active patients with multicompartmental chondral disease, leading to improved clinical outcomes and low reoperation and failure rates at midterm follow-up.

Microencapsulated rabbit adipose stem cells initiate tissue regeneration in a rabbit ear defect model

Cell-based tissue engineering can promote cartilage tissue regeneration, but cell retention in the implant site post-delivery is problematic. Alginate microbeads containing adipose stem cells (ASCs) pretreated with chondrogenic media have been used successfully to regenerate hyaline cartilage in critical size defects in rat xiphoid suggesting that they may be used to treat defects in elastic cartilages such as the ear. To test this, we used microbeads made with low viscosity, high mannuronate medical grade alginate using a high electrostatic potential, and a calcium cross linking solution containing glucose. Microbeads containing rabbit ASCs (rbASCs) were implanted bilaterally in 3 mm critical size midcartilage ear defects of six skeletally mature male New Zealand White rabbits (empty defect; microbeads without cells; microbeads with cells; degradable microbeads with cells; and autograft). Twelve weeks post-implantation, regeneration was assessed by microCT and histology. Microencapsulated rbASCs cultured in chondrogenic media expressed mRNAs for aggrecan, Type II collagen, and Type X collagen. Histologically, empty defects contained fibrous tissue; microbeads without cells were still present in defects and were surrounded by fibrous tissue; nondegradable beads with rbASCs initiated cartilage regeneration; degradable microbeads with cells produced immature bone-like tissue, also demonstrated by microCT; and autografts appeared as normal auricular cartilage but were not fully integrated with the tissue surrounding the defect. Elastin, the hallmark of auricular cartilage, was not evident in the neocartilage. This delivery system offers the potential for regeneration of auricular cartilage, but vascularity of the treatment site and use of factors that induce elastin must be considered.

Treatment of Failed Articular Cartilage Reconstructive Procedures of the Knee: A Systematic Review

Background

Symptomatic articular cartilage lesions of the knee are common and are being treated surgically with increasing frequency. While many studies have reported outcomes following a variety of cartilage restoration procedures, few have investigated outcomes of revision surgery after a failed attempt at cartilage repair or reconstruction.

Purpose

To investigate outcomes of revision cartilage restoration procedures for symptomatic articular cartilage lesions of the knee following a previously failed cartilage reconstructive procedure.

Study Design

Systematic review; Level of evidence, 4.

Methods

A literature search was performed by use of the PubMed, EMBASE, and MEDLINE/Ovid databases for relevant articles published between 1975 and 2017 that evaluated patients undergoing revision cartilage restoration procedure(s) and reported outcomes using validated outcome measures. For studies meeting inclusion criteria, relevant information was extracted.

Results

Ten studies met the inclusion criteria. Lesions most commonly occurred in the medial femoral condyle (MFC) (52.8%), with marrow stimulation techniques (MST) the index procedure most frequently performed (70.7%). Three studies demonstrated inferior outcomes of autologous chondrocyte implantation (ACI) following a previous failed cartilage procedure compared with primary ACI. One study comparing osteochondral allograft (OCA) transplant following failed microfracture (MFX) with primary OCA transplant demonstrated similar clinical outcomes and graft survival at midterm follow-up. No studies reported outcomes following osteochondral autograft transfer (OAT) or newer techniques.

Conclusion

This systematic review of the literature reporting outcomes following revision articular cartilage restoration procedures (most commonly involving the MFC) demonstrated a high proportion of patients who underwent prior MST. Evidence is sufficient to suggest that caution should be taken in performing ACI in the setting of prior MST, likely secondary to subchondral bone compromise. OCA appears to be a good revision treatment option even if the subchondral bone has been violated from prior surgery or fracture.