Prospective evaluation of prolonged fresh osteochondral allograft transplantation of the femoral condyle: minimum 2-year follow-up

Fresh osteochondral allograft transplantation for knee full-thickness articular cartilage lesions using femoral head of living donors: short-term results

BACKGROUND

Fresh osteochondral allograft transplantation is a good treatment option of cartilage defects. However, this treatment option is not available in all countries due to limited graft availability and tissue banks limitations. The purpose of this study is to assess the short term functional and imaging outcomes of fresh osteochondral allograft transplantation in the knee using the femoral head of living donors.

HYPOTHESIS

Fresh osteochondral allografts from the femoral heads of living donors is a valid graft source for management of distal Femur cartilage defects. This technique can improve functional knee scores with good radiological outcomes.

STUDY DESIGN

Prospective case series.

METHODS

Fifteen patients with full thickness cartilage defects of the distal femur underwent osteochondral allograft transplantation from the femoral heads of living donors. Grafts were transplanted by both shell and multiple dowels techniques. The average follow up duration was 18.3 months (range, 12-25 months). Patients were evaluated by Lysholm and International Knee Documentation Committee (IKDC) scores, radiography and MR imaging using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

There was a statistically significant improvement (P < 0.001) in both Lysholm and IKDC average scores at 6 months and 12 months postoperative. Postoperative MRI was done at an average 6.8 months (range, 5-11 months) postoperative. The mean total OCAMRISS score was 3.4 (range, 1-7). A second look arthroscopy was done in four patients and showed intact articular cartilage in all three patients.

CONCLUSION

Femoral head of living donors is a valid new source for fresh osteochondral allograft transplantation of knee osteochondral lesions. Short term results showed improvement in clinical assessment scores. Follow up imaging showed graft incorporation and good MRI scores.

Subchondral bone: An emerging target for the treatment of articular surface lesions of the knee

Purpose

When dealing with the health status of the knee articular surface, the entire osteochondral unit has gained increasing attention, and in particular the subchondral bone, which plays a key role in the integrity of the osteochondral unit. The aim of this article was to discuss the current evidence on the role of the subchondral bone.

Methods

Experts from different geographical regions were involved in performing a review on highly discussed topics about the subchondral bone, ranging from its etiopathogenetic role in joint degeneration processes to its prognostic role in chondral and osteochondral defects, up to treatment strategies to address both the subchondral bone and the articular surface.

Discussion

Subchondral bone has a central role both from an aetiologic point of view and as a diagnostic tool, and its status was found to be relevant also as a prognostic factor in the follow-up of chondral treatment. Finally, the recognition of its importance in the natural history of these lesions led to consider subchondral bone as a treatment target, with the development of osteochondral scaffolds and procedures to specifically address osteochondral lesions.

Conclusion

Subchondral bone plays a central role in articular surface lesions from different points of view. Several aspects still need to be understood, but a growing interest in subchondral bone is to be expected in the upcoming future towards the optimization of joint preservation strategies.

Level of Evidence

Level V, expert opinion.

High tibial osteotomy combined with cartilage restoration: A systematic review of clinical outcomes and prognostic factors

Background

Focal chondral defects are often treated with cartilage restoration procedures. Malalignment often accompanies chondral defects. High tibial osteotomy (HTO), classically utilized to treat uni-compartmental knee osteoarthritis, corrects malalignment. HTO combined with cartilage restoration procedures can treat uni-compartmental osteoarthritis and focal chondral defects.

Purpose

To assess outcomes of combined HTO and cartilage restoration procedures and review prognostic factors that may assist in preoperative planning and patient counseling.

Study design

Systematic Review of published literature.

Methods

A systematic review of PubMed and Scopus was performed following PRISMA guidelines. Thirty-four papers were included in qualitative considerations.

Results

Thirty-four papers that reported the combined outcome of HTO and cartilage repair were included. Twenty of the 34 included papers reported prognostic factors that affected the success or failure of combined HTO and cartilage repair surgery for focal articular defect and uni-compartmental knee osteoarthritis. Cartilage repair techniques that were combined with HTO and included in this review are bone marrow stimulation, allograft transplantation, osteochondral autograft transplantation, autologous chondrocyte implantation, and mesenchymal stem cell implantation.

Conclusions

HTO with adjunctive cartilage repair procedures improve clinical outcome scores and restore alignment in patients with medial compartment osteoarthritis and isolated focal chondral defects. HTO with adjunctive cartilage procedures produces optimal results in younger, non-obese patients with focal chondral defects and varus malalignment, without significant lateral compartment and patellofemoral involvement.

Outcomes and Return to Sport After Knee Osteochondral Allograft Transplant in Professional Athletes

Background

Limited data are available on the outcomes and return-to-sport rates after osteochondral allograft transplant in professional athletes.

Purpose

To evaluate the experience of a single senior surgeon in treating professional athletes with osteochondral allograft transplant, including analyzing clinical outcomes and return to sport.

Study Design

Case series; Level of evidence, 4.

Methods

The authors performed a retrospective review of professional athletes treated with primary osteochondral allograft to the knee between January 1, 2001, and January 1, 2021, by a single surgeon. Athletes were required to play at the professional level in their sport and have a minimum of 2 years of follow-up. Return-to-sport rates and timing were evaluated. Patient-reported outcomes were assessed preoperatively and at final follow-up. Reoperations and failures were also tabulated.

Results

The study included 15 professional athletes who represented a variety of sports, with follow-up at a mean of 4.91 ± 2.2 years (range, 2.0-9.4 years). The majority (8 athletes; 53%) had undergone prior surgeries to the operative knee. Eleven (73%) returned to sport at a mean of 1.22 ± 0.4 years (range, 0.75-2 years), and of the 8 undergoing isolated osteochondral allograft, 7 (87.5%) returned at 1.28 ± 0.3 years. Ten athletes (66.7% of total; 90.9% of those who returned) returned to sport at the same level or higher compared with before surgery. Significant improvements were seen in each assessed patient-reported outcome score at final follow-up. Two of the 3 (66.7%) patients who underwent concomitant meniscal allograft transplant were able to return to sport at the same level or higher than presurgery. Three (20%) underwent second-look arthroscopy, 1 (6.7%) of whom underwent cartilage debridement of the osteochondral allograft.

Conclusion

Osteochondral allograft transplant in professional athletes can result in a high rate of return to play at a similar or higher level as presurgery, even when performed with concomitant procedures such as meniscal allograft transplant. High-level athletes should expect significant postoperative improvement in clinical outcomes.

Conversion Total Knee Arthroplasty after Failed Osteochondral Allograft Reconstruction: Similar Functional Performance with Lower Patient Satisfaction

BACKGROUND

This study presents surgical techniques used in conversion total knee arthroplasty (cTKA) following early failure of large osteochondral allograft joint replacement and compares postoperative patient reported outcomes measures (PROMs) and satisfaction scores with a contemporary primary total knee arthroplasty (pTKA) cohort.

METHODS

We retrospectively evaluated 25 consecutive cTKA patients (26 procedures) to define utilized surgical techniques, radiographic disease severity, preoperative and postoperative PROMs (visual analog scale (VAS) pain, knee injury and osteoarthritis outcome score for joint replacement (KOOS-JR), University of California Los Angeles (UCLA) Activity), expected improvement and postoperative satisfaction (5-point Likert), and reoperations in comparison with an age and body mass index (BMI) propensity matched cohort of 50 pTKA performed for osteoarthritis (52 procedures).

RESULTS

Revision components were used in 12 cTKA cases (46.1%), with 4 cases requiring augmentation (15.4%), and 3 cases utilizing varus-valgus constraint (11.5%). While no significant differences were noted in expectation level or in other PROMs, mean patient reported satisfaction was lower in the conversion group (4.4 +/- 1.1 vs 4.8 +/- 0.5 points, P=0.02). High cTKA satisfaction was associated with higher postoperative KOOS-JR (84.4 vs 64.2 points, P=0.01) and trend towards higher UCLA activity (6.9 vs 5.7 points, P=0.08). Four patients in each group underwent manipulation (15.3 vs 7.6%, P=0.42), and one primary TKA patient was treated for early postoperative infection (0 vs 1.9%, P=1.0).

CONCLUSION

Conversion TKA following failed biological replacement was associated with similar postoperative improvement as in pTKA. Lower patient reported cTKA satisfaction was associated with lower postoperative KOOS-JR scores.

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.

Outcomes of Plug Osteochondral Allograft Transplantation With or Without Concomitant Osteotomy for Cartilage Defects in the Knee: Minimum 2-year Follow-up

INTRODUCTION

Isolated osteochondral defects of the knee can cause notable pain and disability. Osteochondral allograft (OCA) transplantation using trephined plug grafts is a highly effective, often curative, treatment option. In knees with malalignment into the transplanted compartment, osteotomy can be done concurrently. This study investigates early-to-midterm survivorship, as well as clinical and radiographic outcomes, of plug OCAs with and without concomitant osteotomy in the knee.

METHODS

Plug OCA was done on active, young to middle-aged patients with osteochondral defects ≤4 cm diameter. Prospectively collected data for 102 patients who underwent plug OCA between 2004 and 2020 were reviewed. Survivorship according to Kaplan-Meier analysis was the primary outcome. Failure was defined as conversion to total knee arthroplasty or repeat allograft. Clinical and radiographic outcomes were evaluated using the modified Hospital for Special Surgery (mHSS) score and Kellgren-Lawrence grading.

RESULTS

Eighty-six patients with a mean age of 29 ± 9.7 years (15 to 54) and a mean follow-up of 6.8 ± 3.7 years (2 to 15.9) were studied. Concomitant realignment osteotomy was done in 66 patients (76.7%). Graft survivorship was 100%, 93.8% (95% confidence interval 90.8% to 96.8%), and 89.7% (95% confidence interval 85.6% to 93.8%) at 2, 5, and 10 to 15 years, respectively. Six grafts (7.0%) required knee arthroplasty at a mean of 4.6 ± 1.8 years (2.2 to 7.1). Most common reasons for revision surgeries with graft retention included implant removal (11.6%), débridement (8.1%), and repeat osteotomy (5.8%). The mean mHSS score of 90.8 ± 10.4 (51 to 100) at the final follow-up was significantly higher than the preoperative value of 72.5 ± 12.1 (36 to 90) (P < 0.001). Subgroup analyses revealed a markedly greater risk of failure in grafts with a diameter of 30 mm or larger.

DISCUSSION

Plug OCA with or without concurrent realignment osteotomy resulted in an excellent graft survival of 93% at a mean of 6.8 years, with reliable functional improvement demonstrated by notable improvements in mHSS knee scores.

Subsequent Surgery Up to 10 Years After Osteochondral Allograft and Osteochondral Autograft: An Analysis of More Than 2000 Patients

Background

Osteochondral allograft transplant (OCA) and osteochondral autograft transfer (OAT) replace damaged cartilage with a plug of bone and overlying articular cartilage; however, limited research is available regarding the survival of these osteoarticular grafting procedures.

Hypothesis

We hypothesized that patients who underwent OCA would have a higher rate of subsequent surgery over the course of 5 years compared with patients who underwent OAT.

Study Design

Cohort study; Level of evidence, 3.

Methods

The PearlDiver Mariner administrative database was used to identify patients 10 to 59 years old who had undergone OCA or OAT between 2010 and 2018. All included patients were assessed for subsequent knee surgeries, defined by the occurrence of a subsequent osteochondral procedure (OCA or OAT) or any type of knee arthroplasty for the duration of the time they were included in the data set (maximum of 10 years). Analyses were performed for the total population and those with allograft versus autograft (compared using the Fisher exact test). The 5-year Kaplan-Meier survival curves for operation-free survival were compared using a Mantel-Cox log-rank test.

Results

In total, 2598 patients were identified: 1631 patients who underwent OCA (34.5 ± 12.1 years old; 51.6% female) and 967 patients who underwent OAT (32.1 ± 12.9 years old; 51.0% female). Both groups had similarly high rates of subsequent knee surgeries (23.9% vs 21.9%, respectively; P = .249), with no statistical differences in rates of subsequent surgery between groups. Kaplan-Meier survival curves comparing operation-free survival at 5 years indicated no significant difference between the groups (OCA, 88.0% vs OAT, 89.5%; P = .235).

Conclusion

Both osteochondral grafting procedures carried a relatively high rate of secondary surgery, which increased with time. The 5-year survival analysis revealed similarly high rates of subsequent surgery.

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.

Association of Sex Mismatch Between Donor and Recipient With Graft Survivorship at 5 Years After Osteochondral Allograft Transplantation

BACKGROUND

Sex mismatch between donor and recipient has been considered a potential contributor to adverse outcomes after solid organ transplantation. However, the influence of sex mismatching in osteochondral allograft (OCA) transplantation has yet to be determined.

PURPOSE

To evaluate whether donor-recipient sex mismatching affects graft survival after OCA transplantation.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In this review of prospectively collected data, patients who underwent OCA transplantation between November 2013 and November 2017 by a single surgeon were analyzed. Cumulative survival was assessed via the Kaplan-Meier method using log-rank tests to compare patients with similar donor groups. Multivariable Cox regression analysis adjusted for patient age, graft size, and body mass index was used to evaluate the influence of donor-recipient sex on graft survival.

RESULTS

A total of 154 patients were included: 102 (66.2%) who received OCAs from a same-sex donor and 52 (33.8%) who received OCAs from a different-sex donor. At 5-year follow-up, a significantly lower graft survival rate was observed for different-sex donor transplantation in comparison with same-sex donorship (63% vs 92%; P = .01). When correcting for age, graft size, and body mass index, donor-recipient sex-mismatch transplantation demonstrated a 2.9-times greater likelihood to fail at 5 years compared with donor-recipient same-sex transplantation (95% CI, 1.11-7.44; P = .03). A subgroup analysis showed no significant difference in graft survival between the female-to-female and female-to-male groups (91% and 84%, respectively). Conversely, male-to-male transplantation demonstrated a significantly higher cumulative 5-year survival (94%; P = .04), whereas lower survival was found with male-to-female donorship (64%; P = .04). Multivariable Cox regression indicated a 2.6-times higher likelihood of failure for the male-to-female group in comparison with the other groups (95% CI, 1.03-6.69; P = .04). Male-to-male transplantation had a tendency toward decreased likelihood of OCA failure (hazard ratio, 0.33), although without statistical significance (95% CI, 0.11-1.01; P = .052).

CONCLUSION

Mismatch between donor and recipient sex had a negative effect on OCA survival after transplantation, particularly in those cases when male donor tissue was transplanted into a female recipient.

Reconstruction of Massive Segmental Distal Femoral Metaphyseal Bone Defects After Open Injury: A Study of 20 Patients Managed with Intercalary Gamma-Irradiated Structural Allografts and Autologous Cancellous Grafts

BACKGROUND

Our aim was to examine the outcome of gamma-irradiated intercalary structural allografts combined with autologous cancellous grafts in treating large metaphyseal bone defects of the distal femur following open injuries.

METHODS

We prospectively included 20 consecutive patients with large metaphyseal bone defects of >4 cm located in the region of the distal femur following open injuries treated between 2010 and 2018, with a mean follow-up of 2 years (range, 2 to 10 years). Of these patients,18 were men and 2 were women. The mean age was 39 years (range, 22 to 72 years). The mean length of the bone defects was 10.1 cm (range, 5.5 to 14.5 cm), and all were in the metaphysis of the distal femur. The surgical technique included initial early debridement and external fixation followed by reconstruction of the bone defect using structural allograft combined with autologous cancellous bone graft harvested from the iliac crest and locking plate fixation. Definitive fixation was performed at an average period of 22.5 days (range, 3 to 84 days) after injury. Osseous union, rate of infection, complications, need for secondary procedures, and functional outcome using the Lower Extremity Functional Scale (LEFS) at the final follow-up were assessed.

RESULTS

After excluding 1 patient who was lost to follow-up, 19 patients with complete follow-up were available for analysis. Of those, 13 patients (68%) achieved complete union at both ends of the allograft with host bone without any further intervention. Three patients (16%) developed aseptic nonunion of the proximal end of the allograft requiring 1 additional procedure each to achieve union. Four patients (21%) developed a deep surgical site infection. Of those, 1 elderly patient required above-the-knee amputation following uncontrolled diabetes and infection. A second patient required 2 additional procedures, and a third patient needed 4 additional procedures to achieve union. The fourth patient developed infection after achieving union, and the infection subsided after debridement and implant removal. The mean LEFS score for all 19 patients was 55 (range, 41 to 75).

CONCLUSIONS

Use of allograft was a reasonable single-stage alternative solution for massive distal femoral bone defects, which united without additional surgery in two-thirds of the patients and without limb-length discrepancy.

LEVEL OF EVIDENCE

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

Quality and Variability of Physical Therapy Protocols Varies Widely for Osteochondral Allograft Transplantation of the Femoral Condyles

OBJECTIVE

To assess the quality and variability of osteochondral allograft (OCA) transplantation rehabilitation protocols associated with academic orthopedic programs in the United States.

DESIGN

A systematic review was performed to collect all publicly available online rehabilitation protocols for femoral condyle OCA transplant from US academic orthopedic programs participating in the Electronic Residency Application Service. These protocols were evaluated for inclusion of different rehabilitation components as well as timing of suggested initiation of these activities.

RESULTS

A total of 22 protocols were included. Although 91% of protocols recommended bracing, wide variation exists in total time of utilization. Median time for full weight bearing (FWB) was 7 weeks (range 4-8). On average, each protocol mentioned 9 (range 2-18) different strengthening exercises. The median time suggested to return to high-impact activities was 9 months (range 8-12). Only 3 protocols (14%) offered criteria of advancement for each phase as well as criteria for discharge.

CONCLUSION

Very few of the academic orthopedic programs have published online rehabilitation protocols following OCA transplantation. Although there is wide variation between the protocols, it allowed the identification of trends or patterns that are more common. However, there is need for more standardized evidence-based rehabilitation protocols which are easy to understand and follow by patients.

Fresh Osteochondral Allograft Transplantation in the Knee: A Viability and Histologic Analysis for Optimizing Graft Viability and Expanding Existing Standard Processed Graft Resources Using a Living Donor Cartilage Program

OBJECTIVE

This study aims to (1) determine and validate living cartilage allograft transplantation as a novel source for viable osteochondral allograft (OCA) tissues and (2) perform histologic and viability comparisons of living donor cartilage tissues to currently available clinical-grade standard processed grafts.

DESIGN

Using healthy cartilage from well-preserved contralateral compartments in 27 patients undergoing total knee arthroplasty (TKA) and 10 clinical-grade OCA specimens obtained immediately following operative implantation, standard and living donor OCA quality was evaluated at the time of harvest and following up to 3 weeks of storage on the basis of macroscopic International Cartilage Repair Society grade, histology, and viability.

RESULTS

Osteochondral samples demonstrated a consistent decrease in viability and histologic quality over the first 3 weeks of storage at 37°C, supporting the utility of an OCA paradigm shift toward early implantation, as was the clinical standard up until recent adoption of transplantation at 14 to 35 days following donor procurement. Samples from the 10 clinical-grade OCAs, implanted at an average of 23 days following graft harvest demonstrated a mean viable cell density of 45.6% at implantation, significantly lower (P < 0.01) than the 93.6% viability observed in living donor allograft tissues.

CONCLUSIONS

Osteochondral tissue viability and histologic quality progressively decreases with ex vivo storage, even when kept at physiologic temperatures. Currently available clinical OCAs are stored for 2 to 5 weeks prior to implantation and demonstrate inferior viability to that of fresh osteochondral tissues that can be made available through the use of a living donor cartilage program.

Modernizing Storage Conditions for Fresh Osteochondral Allografts by Optimizing Viability at Physiologic Temperatures and Conditions

Objective. Osteochondral allograft (OCA) transplantation has demonstrated good long-term outcomes in treatment of cartilage defects. Viability, a key factor in clinical success, decreases with peri-implantation storage at 4°C during pathogen testing, matching logistics, and transportation. Modern, physiologic storage conditions may improve viability and enhance outcomes. Design. Osteochondral specimens from total knee arthroplasty patients (6 males, 5 females, age 56.4 ± 2.2 years) were stored in media and incubated at normoxia (21% O₂) at 22°C or 37°C, and hypoxia (2% O₂) at 37°C. Histology, live-dead staining, and quantitative polymerase chain reaction (qPCR) was performed 24 hours after harvest and following 7 days of incubation. Tissue architecture, cell viability, and gene expression were analyzed. Results. No significant viability or gene expression deterioration of cartilage was observed 1-week postincubation at 37°C, with or without hypoxia. Baseline viable cell density (VCD) was 94.0% ± 2.7% at day 1. At day 7, VCD was 95.1% (37°C) with normoxic storage and 92.2% (37°C) with hypoxic storage (P ≥ 0.27). Day 7 VCD (22°C) incubation was significantly lower than both the baseline and 37°C storage values (65.6%; P < 0.01). COL1A1, COL1A2, and ACAN qPCR expression was unchanged from baseline (P < 0.05) for all storage conditions at day 7, while CD163 expression, indicative of inflammatory macrophages and monocytes, was significantly lower in the 37°C groups (P < 0.01). Conclusion. Physiologic storage at 37°C demonstrates improved chondrocyte viability and metabolism, and maintained collagen expression compared with storage at 22°C. These novel findings guide development of a method to optimize short-term fresh OCA storage, which may lead to improved clinical results.

The Role of Hypertension in Cartilage Restoration: Increased Failure Rate After Autologous Chondrocyte Implantation but Not After Osteochondral Allograft Transplantation

Objectives. The purpose of this study was to examine whether patients with diagnosed hypertension have an increased risk of graft failure following cartilage repair with either autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA). We hypothesized that hypertension is related to higher ACI and OCA graft failure. Design. Patients who underwent ACI or OCA transplantation between February 2009 and December 2016 were included in this study. Inclusion criteria were (1) at least 2 years' follow-up, (2) available information related to the living habits (smoking and medication status), and (3) available information related to the presence of hypertension, diabetes mellitus, or hyperlipidemia. To identify potential independent risk factors of graft failure, univariate screening was performed and factors with significance at a level of P < 0.1 were entered in multivariate logistic regression models. Results. A total of 368 patients (209 ACI and 159 OCA) were included into our study. In the ACI group, 61 patients' (29.1%) graft failed. Univariate screening identified older age, female gender, defect size, higher prevalence of hypertension, and smoking as a predictor of graft failure. Following, multivariate logistic regression revealed female gender (odds ratio [OR] 1.02, P = 0.048), defect size (OR 1.07, P = 0.035), and hypertension (OR 3.73, P = 0.023) as significant independent risk factors predicting graft failure after ACI. In the OCA group, 29 patients' (18.2%) graft failed and none of the included factors demonstrated to be a potential risk factor for graft failure. Conclusion. Hypertension, defect size, and female gender seem to predict ACI graft failure but not OCA failure.

Bone Marrow Lesions on Preoperative Magnetic Resonance Imaging Correlate With Outcomes Following Isolated Osteochondral Allograft Transplantation

PURPOSE

The purpose of this study was to investigate the role of preoperative bone marrow lesion (BML) size and location on (1) postoperative patient reported outcomes and (2) postoperative failure and time to failure after osteochondral allograft (OCA) transplantation.

METHODS

Consecutive patients from 2 senior surgeons who underwent isolated OCA transplantation to the knee from 2009-2018 were identified for the case series. Preoperative magnetic resonance imaging (MRI) was evaluated for BMLs based on 2 classification systems (Welsch et al. and Costa-Paz et al.) by 2 independent graders. BMLs associated with minimum 1-year postoperative outcomes were evaluated, and the effect of BML classification on survivorship was investigated with Kaplan-Meier curves.

RESULTS

The 77 patients who underwent isolated OCA transplantation (mean follow-up: 39.46 ± 22.67 months) and had preoperative MRIs were included. Within this cohort, 82% of patients demonstrated a BML. The preoperative Costa-Paz et al. classification was significantly positively correlated with the postoperative Visual Analog Scale, International Knee Documentation Committee and Veterans RAND 12-Item Health Survey raw scores for both graders (P < 0.05). Failure occurred in 5 of 65 (8%) patients at a mean of 22.86 ± 12.04 months postoperatively. The presence of BML alone did not significantly affect survival (P = 0.780). However, for 1 grader, the Welsch et al. classification was associated with increased risk of graft failure (P = 0.031).

CONCLUSION

Preoperative subchondral BMLs were present in 82% of patients undergoing OCA transplantation. We found that more severe BMLs based on the Costa-Paz classification, with increasing involvement in the juxta-articular surface, were correlated with higher postoperative patient-reported functional outcomes after OCA. BMLs may be associated with an increase in graft failure, but their role in this remains unclear.

LEVEL OF EVIDENCE

IV, Retrospective Case Series.

Does Flipping the Tubercle for Improved Cartilage Repair Exposure Increase the Risk for Arthrofibrosis?

OBJECTIVE

We sought to determine whether rates of postoperative arthrofibrosis following tibial tuberosity osteotomy (TTO) with complete mobilization of the fragment (TTO-HD) are comparable to TTOs where the hinge remained intact (TTO-HI).

DESIGN

Patients who underwent TTO with concomitant cartilage repair procedure between January 2007 and May 2017, with at least 2 years of follow-up were included in this study. Postoperative reinterventions following TTO-HD and TTO-HI were assessed and multivariant logistic regression models were used to identify whether postoperative reinterventions can be attributed to either technique when controlled for defect size or defect number.

RESULTS

A total of 127 patients (TTO-HD, n = 80; TTO-HI, n = 47) were included in this study. Significantly more patients in the TTO-HD group (31.2%) developed postoperative arthrofibrosis compared with TTO-HI (6.4%; P < 0.05). Multivariant logistic regression revealed that TTO-HD is an independent risk factor for predicting postoperative arthrofibrosis (OR 6.5, CI = 1.7-24.2, P < 0.05).

CONCLUSION

Patients who underwent TTO with distal hinge detachment and a proximally flipped tubercle for better exposure during concomitant cartilage repair were at a significantly higher risk of postoperative arthrofibrosis than patients with similar size and number of defects treated without mobilization of the tubercle. While certain procedures can benefit from larger exposure, surgeons should be aware of the increased risk of postoperative arthrofibrosis.

LEVEL OF EVIDENCE

Level III, case-control study.

Treatment of knee osteochondritis dissecans with autologous tendon transplantation: Clinical and radiological results

BACKGROUND

Defect treatment with tendon autograft in osteochondral lesions has been published in the literature with an experimental study in dogs. To demonstrate that it is possible to treat knee osteochondral lesions with the technique of autologous tendon transplantation.

AIM

To evaluate the clinical and radiological results of patients with knee osteochondral lesions who were treated with autologous tendon transplantation.

METHODS

Twenty patients (22 knees) with osteochondritis dissecans (OCD) lesions involving the knee were treated with autologous tendon transplantation between 2005-2018. All lesions were International Cartilage Repair Society grade IV. All patients were evaluated clinically at final follow-up with knee injury and osteoarthritis outcome score (KOOS); and radiologically with magnetic resonance observation and cartilage repair tissue (MOCART) and Kellgren-Lawrence (KL) classification.

RESULTS

A total of 20 patients (22 knees) with a mean age of 25.5± 6.8 years were included. The average defect size was 4.2 ± 2.1 cm², and the average defect depth was 0.9 ± 0.4 cm. Total KOOS score was preoperatively 29.4 ± 5.5 and was later found to be 81.5 ± 5.9 after an average of 68.7 ± 37.7 mo follow-up. The mean MOCART score was 56.2 ± 10.7. Preoperatively, all of the patients had KL grades of 0–1; during the follow-up period, 80% of the patients showed no radiological progress of osteoarthritis. Patients with less than 4 cm² lesion had statistically significantly better overall KOOS than patients whose more than 4 cm² lesion, particularly in sport and quality of life subscales.

CONCLUSION

The autologous tendon transplantation is a single-step, safe, simple, cost-effective method for the treatment of knee OCD with satisfactory clinical and radiological outcomes, particularly in patients with less than 4 cm² lesion.

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.

A Comparison of Outcomes of Revision Surgical Options for the Treatment of Failed Bulk Talar Allograft Transfer: A Systematic Review

Talar bulk osteochondral allograft transplantation is a useful treatment strategy for large, uncontained osteochondral lesions of talus. Complications and high revision rates from osteochondral talar allograft transfer can be common. Talar graft failure is a devastating complication that results from failure of allograft incorporation within the host bone and subsequent resorption and sometimes subsidence can occur. Treatment options and outcomes for graft failure have rarely been reported. The purpose of this study is to evaluate treatment options and their outcomes for treating talar allograft failure. A systematic review was completed to find all reports of salvage treatments for talar graft failure and outcomes of these reports were analyzed. Eleven studies involving a total of 522 ankles, in 520 patients, met the inclusion criteria. The allograft failure rate was 11.5% in these studies with a reoperation rate of 18.9%. With limited reports, satisfactory outcomes for treatment of graft failure with ankle arthrodesis were 77.3%, 50% for revision allograft procedures, and 50% for total ankle arthroplasty. Considering the large failure rate and reoperation rate for bulk talar allograft transplantations, superior revision, and salvage options are needed. More prospective cohort studies focusing on consistent and standard outcome measures are needed to further assess revision options for failed talar allograft procedures.

Osteochondral Allograft Transplantation in Professional Athletes: Rehabilitation and Return to Play

For the treatment of large chondral and osteochondral defects of the knee, osteochondral allograft transplantation (OCA) is an effective solution with relatively high rates of return to sport. In professional athletes, rehabilitation following OCA is a critical component of the process of returning the athlete to full sports activity and requires a multidisciplinary team approach with frequent communication between the surgical and rehabilitation teams (physical therapists, athletic trainers, coaching staff). In this review, we describe our five-phase approach to progressive rehabilitation of the professional athlete after OCA, which takes into account the biological processes of healing and optimization of neuromuscular function required for the demands of elite-level sport. The principles of early range of motion, proper progression through the kinetic chain, avoidance of pain and effusion, optimization of movement, regimen individuation, and integration of sports-specific activities underlie proper recovery.

Clinical Outcomes after Revision of Autologous Chondrocyte Implantation to Osteochondral Allograft Transplantation for Large Chondral Defects: A Comparative Matched-Group Analysis

OBJECTIVE

Osteochondral allograft transplantation (OCA) is a well-established procedure for patients with symptomatic cartilage defects in the knee. Revision to OCA after prior failed cartilage repair has shown similar clinical outcomes as primary OCA; however, most of the failed procedures were arthroscopic procedures for smaller defects. There is no literature investigating the clinical outcomes after OCA for prior failed autologous chondrocyte implantation (ACI) for the treatment of large chondral defects of the knee. The purpose of this study was therefore to determine clinical outcomes of patients undergoing revision to OCA after prior failed ACI as compared with a matched cohort of patients undergoing OCA as a primary cartilage repair procedure (primary OCA).

DESIGN

In this review of prospectively collected data, we analyzed data from 26 patients with at least 2 years follow-up. Thirteen patients who underwent revision to OCA after prior failed ACI by a single surgeon were compared with a matched group of patients who underwent primary OCA. The patients were matched per age, gender, body mass index, and defect size. Patient-reported outcomes, reoperations, and survival rates were compared between groups.

RESULTS

There were no significant differences in patient-reported clinical outcome scores between the groups at final follow-up. Moreover, there was no significant difference in reoperation rates and survival rates between the groups.

CONCLUSION

The present study demonstrates that revision to OCA is a viable treatment option with favorable functional outcomes and similar reoperation and survival rate as primary OCA even for revision of large chondral defects previously treated with ACI.

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.

Cartiform Implantation for focal cartilage defects in the knee: A 2-year clinical and magnetic resonance imaging follow-up study

The purpose of this study was to evaluate clinical and magnetic resonance imaging (MRI) outcomes in patients who underwent cryopreserved viable osteochondral allograft (CVOCA) implantation for focal cartilage defects in the knee at a minimum of 2-years postoperatively. This is a retrospective follow-up study of twelve patients who underwent CVOCA implantation from 2013 to 2015 by a single surgeon for a International Cartilage Repair Society (ICRS) grade 3 or 4 chondral defect. Patient-reported outcome (PRO) measurements and MRI were obtained 2-years postoperatively. Collected PRO measures included: International Knee Documentation Committee (IKDC) form; Visual Analog Scale (VAS) pain score; Veterans RAND 12-Item Health Survey (VR-12); Knee Injury and Osteoarthritis Outcome Score (KOOS); and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). Patients completed a standard return to work and sports/recreation survey. A blinded, fellowship-trained musculoskeletal radiologist independently evaluated each MRI to determine the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Mean follow-up was 2.1 years (2.0-2.3). There were 6 women and 6 men with a mean age of 46.2 ± 11.9 years. Mean PRO scores were: IKDC 72.6 ± 17.4; VAS 2.9 ± 2.8; WOMAC 84.2 ± 15.1; KOOS- Pain 83.8 ± 18.5, Symptoms 77.6 ± 16.0, ADL 88.0 ± 16.9, Sports/Rec 67.7 ± 33.3, QOL 54.8 ± 24.2; and VR-12 PCS 45.0 ± 8.5 and MCS 51.1 ± 9.5. The mean MOCART score was 59.5 ± 12.9. To our knowledge, this is the largest study to report clinical and MRI outcomes of CVOCA implantation in the knee. With positive functional outcomes and lack of failures at 2-year follow-up, CVOCA is a promising treatment option for focal chondral defects in the knee.

STUDY DESIGN

Retrospective case series, Level of evidence 4.

Evolution of a Novel Tissue Preservation Protocol to Optimize Osteochondral Transplantation Outcomes

OBJECTIVE

Osteochondral allograft transplantation is a procedure to treat focal osteochondral lesions (OCLs), but is limited by tissue availability, the quality of transplanted tissue, and inconsistent storage protocols. The objective of this study was to assess the clinical outcomes of a novel tissue procurement, storage, and quality control protocol in treating OCLs.

DESIGN

Prospective case series. Donor cadaveric tissue was processed, stored, and the tissue quality analyzed using the unique tissue preservation protocol developed at our institution. Advanced cross-sectional imaging was used to size match donor tissue with recipient patients. Osteochondral allografts were transplanted using the Arthrex Allograft OATS. Patients were evaluated with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS), and 36-Item Short Form Survey (SF-36) preoperatively and at 1 year and 2 years postoperatively.

RESULTS

Twenty patients (17 knees, 3 shoulders) were included in the study. There was a significant improvement in the following scores: overall WOMAC score, WOMAC function and pain subcategories; KOOS pain, knee-related symptoms, activities of daily living, sports and recreation, and quality of life; SF-36 physical functioning, physical role, pain, and social functioning subcategories; and VAS at all time points postoperatively. There was a significant improvement in WOMAC stiffness at 2 years postoperatively. There were 2 failures, defined by graft subsidence and persistent pain requiring reoperation.

CONCLUSION

The protocol developed at our institution for OAT resulted in significant clinical improvement in patients with OCLs and is an improvement on existing tissue storage techniques.

Osteochondral Injury, Management and Tissue Engineering Approaches

Osteochondral lesions (OL) are a common clinical problem for orthopedic surgeons worldwide and are associated with multiple clinical scenarios ranging from trauma to osteonecrosis. OL vary from chondral lesions in that they involve the subchondral bone and chondral surface, making their management more complex than an isolated chondral injury. Subchondral bone involvement allows for a natural healing response from the body as marrow elements are able to come into contact with the defect site. However, this repair is inadequate resulting in fibrous scar tissue. The second differentiating feature of OL is that damage to the subchondral bone has deleterious effects on the mechanical strength and nutritive capabilities to the chondral joint surface. The clinical solution must, therefore, address both the articular cartilage as well as the subchondral bone beneath it to restore and preserve joint health. Both cartilage and subchondral bone have distinctive functional requirements and therefore their physical and biological characteristics are very much dissimilar, yet they must work together as one unit for ideal joint functioning. In the past, the obvious solution was autologous graft transfer, where an osteochondral bone plug was harvested from a non-weight bearing portion of the joint and implanted into the defect site. Allografts have been utilized similarly to eliminate the donor site morbidity associated with autologous techniques and overall results have been good but both techniques have their drawbacks and limitations. Tissue engineering has thus been an attractive option to create multiphasic scaffolds and implants. Biphasic and triphasic implants have been under explored and have both a chondral and subchondral component with an interface between the two to deliver an implant which is biocompatible and emulates the osteochondral unit as a whole. It has been a challenge to develop such implants and many manufacturing techniques have been utilized to bring together two unalike materials and combine them with cellular therapies. We summarize the functions of the osteochondral unit and describe the currently available management techniques under study.

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.

Complications of En Bloc Osteochondral Talar Allografts and Treatment of Failures: Literature Review and Case Report

Reoperation rates and complication rates can be high for patients receiving an osteochondral talar allograft transplant. Complications can include graft failure, delamination of the graft, arthrofibrosis, advancing osteoarthritis, nonunion of malleolar osteotomies, and partial or complete osteonecrosis of the talus. Graft failure refers to failure of graft incorporation with subsequent necrosis and subsidence. Treatment options for talar graft failure are limited, and outcomes for these treatments have rarely been reported. We present a review of the published data on the complications and treatments for failed talar allograft transplantation. A case report is presented on a young woman who experienced graft failure and osteonecrosis of her talar allograft transplant. Because of the size of the present osteonecrosis, an ankle arthrodesis was performed as the initial revision procedure. Talar necrosis was removed and revascularized from the ankle fusion with solid fusion was confirmed with computed tomography. Symptomatic adjacent joint pain quickly developed in the hindfoot after the ankle fusion, and 12 months later an ankle fusion conversion to total ankle arthroplasty was performed. The patient has returned to normal activity with significant reduction in pain at most recent follow-up visit. This patient was followed for 7 years from initial osteochondral talar allograft transplantation and for 2 years from conversion of ankle fusion to total ankle arthroplasty. It is important to understand the techniques, indications, and outcomes for the various revision options for talar allograft failure. This case report illustrates how multiple revision options can be used to provide the best outcome for the patient.

Clinical Application Status of Articular Cartilage Regeneration Techniques: Tissue-Engineered Cartilage Brings New Hope

Hyaline articular cartilage lacks blood vessels, lymphatics, and nerves and is characterised by limited self-repair ability following injury. Traditional techniques of articular cartilage repair and regeneration all have certain limitations. The development of tissue engineering technology has brought hope to the regeneration of articular cartilage. The strategies of tissue-engineered articular cartilage can be divided into three types: “cell-scaffold construct,” cell-free, and scaffold-free. In “cell-scaffold construct” strategies, seed cells can be autologous chondrocytes or stem. Among them, some commercial products with autologous chondrocytes as seed cells, such as BioSeed®-C and CaReS®, have been put on the market and some products are undergoing clinical trials, such as NOVOCART® 3D. The stem cells are mainly pluripotent stem cells and mesenchymal stem cells from different sources. Cell-free strategies that indirectly utilize the repair and regeneration potential of stem cells have also been used in clinical settings, such as TruFit and MaioRegen. Finally, the scaffold-free strategy is also a new development direction, and the short-term repair results of related products, such as NOVOCART® 3D, are encouraging. In this paper, the commonly used techniques of articular cartilage regeneration in surgery are reviewed. By studying different strategies and different seed cells, the clinical application status of tissue-engineered articular cartilage is described in detail.

Contralateral Lateral Femoral Condyle Allografts Provide an Acceptable Surface Match for Simulated Classic Osteochondritis Dissecans Lesions of the Medial Femoral Condyle

Background:

Osteochondral allograft transplantation is an effective technique for repairing large lesions of the medial femoral condyle (MFC), but its use is limited by graft availability.

Purpose/Hypothesis:

The present study aimed to determine whether contralateral lateral femoral condyle (LFC) allografts can provide an acceptable surface match for posterolateral MFC lesions characteristic of classic osteochondritis dissecans (OCD). The hypothesis was that LFC and MFC allografts will provide similar surface contour matches in all 4 quadrants of the graft for posterolateral MFC lesions characteristic of OCD.

Study Design:

Controlled laboratory study.

Methods:

Ten fresh-frozen recipient human MFCs were each size-matched to 1 ipsilateral medial and 1 contralateral LFC donor (N = 30 condyles). After a nano–computed tomography (nano-CT) scan of the native recipient condyle, a 20-mm circular osteochondral “defect” was created 1 cm posterior and 1 cm medial to the roof of the intercondylar notch (n = 10). A size-matched, random-order donor MFC or LFC plug was then harvested, transplanted, and scanned with nano-CT. Nano-CT scans were then reconstructed, registered to the initial scan of the recipient MFC, and processed in MATLAB to determine the height deviation (d_RMS) between the native and donor surfaces and percentage area unacceptably (>1 mm) proud (%A_proud) and sunken (%A_sunk). Circumferential step-off height (h_RMS) and percentage circumference unacceptably (>1 mm) proud (%C_proud) and sunken (%C_sunk) were measured using DragonFly software. The process was then repeated for the other allograft plug.

Results:

Both MFC and LFC plugs showed acceptable step-off heights in all 4 quadrants (range, 0.53-0.94 mm). Neither allograft type nor location within the defect had a significant effect on step-off height (h_RMS), surface deviation (d_RMS), %A_proud, or %A_sunk. In general, plugs were more unacceptably sunken than proud (MFC, 13.4% vs 2.4%; LFC, 13.2% vs 8.1%), although no significant differences in %C_sunk were seen between allograft types or locations within the defect. In LFC plugs, %C_proud in the lateral quadrant (28.0% ± 26.1%) was significantly greater compared with all other quadrants (P = .0002).

Conclusion:

The present study demonstrates that 20-mm contralateral LFC allografts provide an acceptable surface match for posterolateral MFC lesions characteristic of OCD.

Clinical Relevance:

With comparable surface matching, MFC and LFC allografts can be expected to present similar stresses on the knee joint and achieve predictably positive clinical outcomes, thus improving donor availability and reducing surgical wait times for matches.

Comparative Effectiveness of Cartilage Repair With Respect to the Minimal Clinically Important Difference

BACKGROUND

Recent studies demonstrated a 5% increase in cartilage repair procedures annually in the United States. There is currently no consensus regarding a superior technique, nor has there been a comprehensive evaluation of postoperative clinical outcomes with respect to a minimal clinically important difference (MCID).

PURPOSE

To determine the proportion of available cartilage repair studies that meet or exceed MCID values for clinical outcomes improvement over short-, mid-, and long-term follow-up.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review was performed via the Medline, Scopus, and Cochrane Library databases. Available studies were included that investigated clinical outcomes for microfracture (MFX), osteoarticular transfer system (OATS), osteochondral allograft transplantation, and autologous chondrocyte implantation/matrix-induced autologous chondrocyte implantation (ACI/MACI) for the treatment of symptomatic knee chondral defects. Cohorts were combined on the basis of surgical intervention by performing a meta-analysis that utilized inverse-variance weighting in a DerSimonian-Laird random effects model. Weighted mean improvements in International Knee Documentation Committee (IKDC), Lysholm, and visual analog scale for pain (VAS pain) scores were calculated from preoperative to short- (1-4 years), mid- (5-9 years), and long-term (≥10 years) postoperative follow-up. Mean values were compared with established MCID values per 2-tailed 1-sample Student t tests.

RESULTS

A total of 89 studies with 3894 unique patients were analyzed after full-text review. MFX met MCID values for all outcome scores at short- and midterm follow-up with the exception of VAS pain in the midterm. OATS met MCID values for all outcome scores at all available time points; however, long-term data were not available for VAS pain. Osteochondral allograft transplantation met MCID values for IKDC at short- and midterm follow-up and for Lysholm at short-term follow-up, although data were not available for other time points or for VAS pain. ACI/MACI met MCID values for all outcome scores (IKDC, Lysholm, and VAS pain) at all time points.

CONCLUSION

In the age of informed consent, it is important to critically evaluate the clinical outcomes and durability of cartilage surgery with respect to well-established standards of clinical improvement. MFX failed to maintain VAS pain improvements above MCID thresholds with follow-up from 5 to 9 years. All cartilage repair procedures met MCID values at short- and midterm follow-up for IKDC and Lysholm scores; ACI/MACI and OATS additionally met MCID values in the long term, demonstrating extended maintenance of clinical benefits for patients undergoing these surgical interventions as compared with MFX.

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.

Basic fibroblast growth factor and agarose gel promote ​the ability of immune privilege of allogeneic cartilage transplantation in rats

Objective

Allogeneic cartilage transplantation is used to treat severe osteochondral defects or cartilaginous injury. However, acute immune rejection has been a key problem interfering with graft healing.

Methods

Full-thickness osteochondral defects were performed in Sprague Dawley rats. The allograft implants were set into the defect region. Blood and spleen samples from Postoperative Day 3 onward were collected for inflammatory cell analysis, including analysis of monocytes, natural killer cells, CD4⁺CD25⁺Foxp3⁺ regulatory T cells, CD4⁺ T cells, and CD8⁺ T cells. Gross observation and histologic staining (hematoxylin and eosin, toluidine blue) were carried out at the same time point to assess the repair effect of the cartilage graft and the degree of immune rejection.

Results

Treatment with basic fibroblast growth factor, agarose gel, and allogeneic cartilage was similar to that of the autologous group. The percentage of monocytes in allografts was at a higher level in the spleen and blood; the frequency of CD4⁺ T cells in the allogeneic group was higher than in the autologous group and the other agarose groups at 6 weeks after transplantation. The number of regulatory T cells in the autograft was increased from Postoperative Week 1; similar results were observed in groups containing basic fibroblast growth factor beginning at Postoperative Week 3.

Conclusions

Allogeneic cartilage transplantation induces acute immune rejection, which compromises the validity of the implant. The combination of basic fibroblast growth factor and agarose gel facilitates the goal of immune privilege and promotes the success of the allograft tissues.

The translational potential of this article

This study investigated the combination of basic fibroblast growth factor (bFGF) and agarose gel facilitates promotes the success of the allograft tissues transplantation. This work may help clinicians find a new way to repair articular cartilage damage. This will affect the treatment of articular cartilage movement injuries and arthritis.

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.

OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION for the KNEE: POST-OPERATIVE REHABILITATION

Articular cartilage injuries of the knee are common among young, active patients presenting with knee pain, swelling, and/or mechanical symptoms. These injuries have limited healing potential due to the avascular nature of hyaline cartilage. While several treatment options exist, osteochondral allograft (OCA) transplantation for the knee has been used successfully in primary management of large chondral or osteochondral defects and salvage of previously failed cartilage repair. OCA transplantation potentially yields a natural, matching contour of the native recipient surface anatomy and transplants mature, viable hyaline cartilage to the affected defect. Following OCA transplantation, strict compliance with a rehabilitation protocol is essential to enable optimal recovery. The outlined rehabilitation protocol is informed by the existing literature and incorporates current rehabilitation principles, the science of osteochondral incorporation, and adaptations based on an individual's readiness to progress through subsequent phases. The purpose of this clinical commentary is to discuss the diagnosis, surgical management, and post-operative rehabilitation following OCA transplantation and to assist the physical therapist in returning athletes to full sports participation.

Establishing Clinically Significant Outcomes After Meniscal Allograft Transplantation

Background:

Traditionally, the primary outcome in meniscal allograft transplantation (MAT) has been long-term survivorship; however, short-term clinically significant outcomes are necessary to fully evaluate patient improvement after surgery.

Purpose:

To (1) establish the minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) with respect to patient-reported outcome measures (PROMs) and (2) evaluate preoperative and intraoperative variables correlated with achieving these threshold values.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

A prospectively maintained institutional registry was queried for all MATs performed between 1999 and 2017. The following PROM scores were collected: International Knee Documentation Committee (IKDC) score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS). Patients who completed preoperative and postoperative PROMs within a 1-month window were included to calculate the distribution-based MCID at this interval. An anchor question regarding satisfaction with surgery was asked at the same time point and was employed to determine the PASS using nonparametric receiver operating characteristic curve/area under the curve analysis. Multivariate regression analysis was performed to correlate patient demographics, medical history, and concomitant procedures to propensity in achieving the MCID and PASS.

Results:

A total of 98 patients who underwent MAT met the inclusion/exclusion criteria, of whom 10 underwent concomitant ligamentous procedures, 65 underwent concomitant cartilage procedures, and 7 underwent concomitant realignment procedures. The mean patient age was 29.4 ± 9.0 years, and the mean body mass index (BMI) was 26.8 ± 5.2 kg/m². The distribution-based MCID and PASS were determined for the Lysholm score (12.3 and 66.5) and IKDC (9.9 and 36.0) as well as the KOOS Pain (9.9 and N/A ), Symptoms (9.7 and 73.0), Activities of Daily Living (9.5 and N/A), Sport (13.3 and N/A), and Quality of Life (14.6 and 53.0) subscales, respectively. A preoperative Short Form Physical Component Summary (SF PCS) score greater than 32.0 was predictive of postoperative satisfaction. Patients with work-related claims had a reduced likelihood of achieving the MCID for the IKDC and the PASS for the KOOS Symptoms. An increased BMI was also associated with failing to achieve the PASS for the KOOS Quality of Life (QOL).

Conclusion:

This study established the MCID and PASS for the Lysholm score, IKDC, and KOOS in patients undergoing MAT. Workers’ compensation and higher BMI were associated with failing to achieve clinically significant values. Lower preoperative Lysholm, IKDC, and KOOS scores were predictive of achieving the MCID, while higher preoperative SF PCS scores were associated with achieving satisfaction after MAT.

The Clinical Evidence Behind Biologic Therapies Promoted at Annual Orthopaedic Meetings: A Systematic Review

PURPOSE

The purpose of this study is to systematically evaluate the available clinical data for biologic therapies promoted for articular cartilage defects and osteoarthritis of the knee at the 2016 American Orthopaedic Society for Sports Medicine Meeting (AOSSM) and the 2017 Arthroscopy Association of North America meeting (AANA).

METHODS

Our sample included all exhibitors at the 2016 AOSSM meeting and 2017 AANA meeting. All biologic products marketed at each conference were identified by reviewing exhibition booths and company websites. A systematic review of the clinical data on each product was then completed using PubMed, EMBASE, and the product's own webpage. All clinical peer-reviewed studies with level I-IV evidence were included in the study. Basic science or preclinical studies were excluded.

RESULTS

There were 16 products promoted for biologic therapy for articular cartilage defects or osteoarthritis of the knee at the AOSSM meeting and 11 products promoted at the AANA meeting. A total of 280 articles detailed clinical findings for the articular cartilage products displayed at AOSSM and AANA. Of the 280, there were 36 level I evidence studies, 37 level II evidence studies, 18 level III evidence studies, and 189 level IV evidence studies. Of these articles, 91% were for 4 products. Of all biologic products promoted at the 2 meetings, 65% did not have any peer-reviewed clinical data supporting their use.

CONCLUSION

Overall, many biologic therapies promoted at leading arthroscopy and sports medicine conferences did not have clinical evidence evaluating their use in the peer-reviewed literature. Although scientific advancement requires new technology, orthopaedic surgeons should be cautious about using biologic therapies in their practice with no proven efficacy. There are likely promising new interventions that, with additional scientific research, will be proven efficacious for our patients.

CLINICAL RELEVANCE

This article gives orthopaedic surgeons a detailed example of some of the biologic treatments being offered on the market for the treatment of knee articular cartilage disease. When patients request these treatments, physicians must be able to explain the data supporting their use.

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.

Clinical Outcomes and Failure Rates of Osteochondral Allograft Transplantation in the Knee: A Systematic Review

BACKGROUND

Cartilage lesions are a significant cause of morbidity and impaired knee function; however, cartilage repair procedures have failed to reproduce native cartilage to date. Thus, osteochondral allograft (OCA) transplantation represents a 1-step procedure to repair large chondral defects without the donor site morbidity of osteochondral autograft transplantation.

PURPOSE

To perform a systematic review of clinical outcomes and failure rates after OCA transplantation in the knee at a minimum mean 2 years' 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 transplantation in the knee joint was performed using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, and MEDLINE from studies published between 1980 and 2017. Inclusion criteria were as follows: clinical outcomes and failure rates of OCAs for the treatment of chondral defects in the knee joint, English language, mean follow-up of 2 years and minimum follow-up of 18 months, minimum study size of 20 patients, and human studies. The methodological quality of each study was assessed using a modified version of the Coleman methodology score.

RESULTS

The systematic search identified 19 studies with a total of 1036 patients. The mean 5-year survival rate across the studies included in this review was 86.7% (range, 64.1%-100.0%), while the mean 10-year survival rate was 78.7% (range, 39.0%-93.0%). The mean survival rate was 72.8% at 15 years (range, 55.8%-84.0%) and 67.5% at 20 years (range, 66.0%-69.0%). The weighted mean patient age was 31.5 years (range, 10-82 years), and the weighted mean follow-up was 8.7 years (range, 2-32 years). The following outcome measures showed significant improvement from preoperatively to postoperatively: d'Aubigné-Postel, International Knee Documentation Committee, Knee Society function, and Lysholm scores. The weighted mean reoperation rate was 30.2% (range, 0%-63%). The weighted mean failure rate was 18.2% (range, 0%-31%). Of note, revision cases, patellar lesions, and bipolar lesions demonstrated worse survival rates.

CONCLUSION

Improved patient-reported outcomes can be expected after OCA transplantation, with a survival rate of 78.7% at 10 years. Revision cases, patellar lesions, and bipolar lesions were associated with worse survival rates; therefore, utilization of the most appropriate index cartilage restoration procedure and proper patient selection are key to improving results.

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.

The role of microfractures with tibial osteotomy in the treatment of knee osteoarthritis with a varus deformity

Objective

To evaluate the microfracture intervention with tibial valgus osteotomy associated in the treatment of varus gonarthrosis.

Methods

From November 2005 to May 2013, 129 patients with medial gonarthrosis, varus deformity (8°–12°), and range of movement greater than 90° were evaluated. Patients with advanced gonarthrosis (Alhbäck 3, 4, and 5), Outerbridge lesion inferior to IV, previous knee surgery, body mass index greater than 35 kg/m², and/or cruciate ligament injuries were not included. All patients were treated with videoarthroscopy followed by tibial valgus osteotomy. In the group osteotomy associated with microfracture (n = 56, mean age = 39.3), tibial valgus osteotomy and microfracture techniques to address chondral defects were used. In the isolated osteotomy group (n = 73, mean age = 41.4), only this procedure was performed. Post-surgical follow-up was 24 months, with four evaluations in the first 6 months, proceeding to biannual twice-a-year evaluation in the subsequent period. The Lysholm scale was used for functional monitoring.

Results

There was a significant improvement in the pain, limping, and squatting domains of the Lysholm scale but only in the isolated osteotomy group. A greater variance of results was observed in the osteotomy group associated to microfracture, in addition to an increased risk of functional deterioration (OR = 8.64).

Conclusion

The association of microfractures and tibial valgus osteotomy was correlated to lower functional outcomes than tibial valgus osteotomy alone, and may be related to the risk of worsening in the first two postoperative years.

Reconstruction of Extended Bone Defects Using Massive Allografts Combined with Surgical Angiogenesis: A Case Report

CASE

A 20-year-old patient presented with an extended composite knee defect with destruction of the medial femoral condyle, including the medial collateral ligament. Treatment included using an anterolateral thigh flap for soft-tissue reconstruction, tensor fasciae latae muscle for ligament repair, and a massive allogenic bone graft of the medial femoral condyle that was revascularized with an osteocutaneous composite free flap from the contralateral femur. At 17 months postoperatively, the outcome was evaluated with scores on several established scales and radiographic assessment.

CONCLUSION

The combination of vascularized soft-tissue reconstruction and osseous reconstruction using allogenic bone along with surgical angiogenesis proved to be effective. Complex extremity reconstruction should be discussed with interdisciplinary specialists.

Implantation of a Novel Cryopreserved Viable Osteochondral Allograft for Articular Cartilage Repair in the Knee

Restoration and repair of articular cartilage injuries remain a challenge for orthopaedic surgeons. The standard first-line treatment of articular cartilage lesions is marrow stimulation; however, this procedure can often result in the generation of fibrous repair cartilage rather than the biomechanically superior hyaline cartilage. Marrow stimulation is also often limited to smaller lesions, less than 2 cm². Larger lesions may require implantation of a fresh osteochondal allograft, though a short shelf life, size-matched donor requirements, potential challenges of bone healing, limited availability, and the relatively high price limit the wide use of this therapeutic approach. We present a straightforward, single-stage surgical technique of a novel reparative and restorative approach for articular cartilage repair with the implantation of a cryopreserved viable osteochondral allograft (CVOCA). The CVOCA contains full-thickness articular cartilage and a thin layer of subchondral bone, and maintains the intact native cartilage architecture with viable chondrocytes, growth factors, and extracellular matrix proteins to promote articular cartilage repair. We report the results of a retrospective case series of three patients who presented with articular cartilage lesions more than 2 cm² and were treated with the CVOCA using the presented surgical technique. Patients were followed up to 2 years after implantation of the CVOCA and all three patients had satisfactory outcomes without adverse events. Controlled randomized studies are suggested for evaluation of CVOCA efficacy, safety, and long-term outcomes.

Large fresh osteochondral allografts for the hip: growing the evidence

INTRODUCTION

Articular cartilage lesions of the hip are difficult to effectively treat. Osteochondral allograft (OCA) transplantation in the knee has been associated with long-term success, but OCA for the hip has not been extensively studied. Here, we present the clinical and radiological outcomes from a cohort of 10 patients treated with fresh OCA transplants for large osteochondral defects of the femoral head and/or acetabulum.

METHODS

10 patients who had undergone osteochondral allograft transplantation of the femoral head and/or acetabulum at our institution between 2013 and 2016 were identified from our Institutional Review Board-approved registry. Hip disability and Osteoarthritis Outcome Score (HOOS) was used to track patient progress.

RESULTS

10 patients with an average clinical follow-up of 1.4 years were included in this study. 4 patients were treated solely with OCA plugs for femoral head defects, while the remaining 6 received femoral OCA plugs and at least 1 concomitant procedure for additional intraarticular pathology. 7 patients (70%) had successful functional outcomes, while 3 (30%) had unsuccessful outcomes and were subsequently converted to total hip arthroplasty (THA) 5 to 29 months after OCA.

CONCLUSIONS

OCA transplantation can be an effective treatment strategy for young, healthy individuals with articular cartilage lesions of the hip. Smoking, avascular necrosis aetiology, acetabular involvement and concomitant procedures may be risk factors for unsuccessful outcomes necessitating salvage with THA. Long-term clinical studies to refine indications and determine functional outcomes and survival rates are warranted.

Clinical Outcomes of Osteochondral Allograft Transplantation for Secondary Treatment of Osteochondritis Dissecans of the Knee in Skeletally Mature Patients

PURPOSE

To report clinical outcomes of osteochondral allograft transplantation (OCA) for skeletally mature patients with osteochondritis dissecans (OCD) lesions of the knee in whom prior surgical intervention has failed, and to describe return-to-sport (RTS) rates and any predictive demographic or preoperative variables associated with a higher likelihood to RTS.

METHODS

Patients who underwent OCA by a single surgeon (B.J.C.) between October 1, 2002, and November 30, 2014, for a diagnosis of OCD with a minimum of 2 years' follow-up were included. Demographic, surgical history, operative, and postoperative data points including RTS were analyzed for all patients collectively, with subanalysis to identify any demographic and operative variables associated with the ability to RTS. Failure was defined as revision OCA, gross appearance of graft failure on second-look arthroscopy, or conversion to arthroplasty.

RESULTS

We identified 41 consecutive patients (43 knees), with 37 patients (39 knees, comprising 26 male and 13 female knees) available for clinical follow-up at an average of 7.29 ± 3.30 years. There was significant improvement (P < .05) in all patient-reported outcome scores, with the exception of the Short Form 12 mental subscale (P = .910). Most patients (81.6%) reported being either mostly satisfied or completely satisfied at final follow-up. Of patients self-identifying as athletes preoperatively (n = 22), 18 (81.8%) achieved RTS at an average of 14.0 ± 8.7 months. Athletes with failure to RTS had a significantly greater body mass index (RTS, 24.68 ± 3.67; no RTS, 27.82 ± 0.69; P = .005). Subsequent surgery was performed in 14 patients (35.9%), and primary OCA failed in 2 patients at an average of 6.2 ± 3.8 years.

CONCLUSIONS

OCA is a successful secondary surgical treatment for OCD of the knee in skeletally mature patients and leads to clinically meaningful improvements in patient-reported outcome scores and high patient satisfaction and RTS rates in low-level athletes at an average of 7.29 years' follow-up. Athletes with failure to RTS were found to have a significantly higher body mass index. Although reoperation may be common after OCA (35.9%), the failure rate is low (5.1%) in this series.

LEVEL OF EVIDENCE

Level IV, case series.

Outcomes of cartilage repair techniques for chondral injury in the hip-a systematic review

OBJECTIVE/PURPOSE

The aim of the study was to assess the options of treatment and their related outcomes for chondral injuries in the hip based on the available evidence whilst highlighting new and innovative techniques.

METHODS

A systematic review of the literature from PubMed (Medline), EMBASE, Google Scholar, British Nursing Index (BNI), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Allied and Complementary Medicine Database (AMED) was undertaken from their inception to March 2017 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Clinical outcome studies, prospective/retrospective case series and case reports that described the outcome of cartilage repair technique for the chondral injury in the hip were included. Studies on total hip replacement, animal studies, basic studies, trial protocols and review articles were excluded.

RESULTS

The systematic review found 21 relevant papers with 596 hips. Over 80% of the included studies were published in or after 2010. Most studies were case series or case reports (18 studies, 85.7%). Arthroscopy was used in 11 studies (52.4%). The minimum follow-up period was six months. Mean age of the participants was 37.2 years; 93.5% of patients had cartilage injuries of the acetabulum and 6.5% of them had injuries of the femoral head. Amongst the 11 techniques described in the systematic review, autologous matrix-induced chondrogenesis, osteochondral autograft transplantation and microfracture were the three frequently reported techniques.

CONCLUSION

Over ten different techniques are available for cartilage repair in the hip, and most of them have good short- to medium-term outcomes. However, there are no robust comparative studies to assess superiority of one technique over another, and further research is required in this arena.