Effect of Press-Fit Size on Insertion Mechanics and Cartilage Viability in Human and Ovine Osteochondral Grafts

OBJECTIVE

The osteochondral allograft procedure uses grafts constructed larger than the recipient site to stabilize the graft, in what is known as the press-fit technique. This research aims to characterize the relationships between press-fit size, insertion forces, and cell viability in ovine and human osteochondral tissue.

DESIGN

Human (4 donors) and ovine (5 animals) articular joints were used to harvest osteochondral grafts (4.55 mm diameter, N = 33 Human, N = 35 Ovine) and create recipient sites with grafts constructed to achieve varying degrees of press fit (0.025-0.240 mm). Donor grafts were inserted into recipient sites while insertion forces were measured followed by quantification of chondrocyte viability and histological staining to evaluate the extracellular matrix.

RESULTS

Both human and ovine tissues exhibited similar mechanical and cellular responses to changes in press-fit. Insertion forces (Human: 3-169 MPa, Ovine: 36-314 MPa) and cell viability (Human: 16%-89% live, Ovine: 2%-76% live) were correlated to press-fit size for both human (force: r = 0.539, viability: r = -0.729) and ovine (force: r = 0.655, viability: r = -0.714) tissues. In both species, a press-fit above 0.14 mm resulted in reduced cell viability below a level acceptable for transplantation, increased insertion forces, and reduced linear correlation to press-fit size compared to samples with a press-fit below 0.14 mm.

CONCLUSIONS

Increasing press-fit size required increased insertion forces and resulted in reduced cell viability. Ovine and human osteochondral tissues responded similarly to impact insertion and varying press-fit size, providing evidence for the use of the ovine model in allograft-related research.

Ex vivo storage of human osteochondral allografts: Long-term analysis over 300 days using a Ringer-based solution

Large osteochondral defects are a major challenge in orthopedics, for which osteochondral allograft (OCA) transplantation is nowadays considered as an option, especially in young patients. However, a major issue with OCA is the need for graft storage, which ensures adequate cartilage integrity over time. The aim of this study was to test how long a Ringer-based storage solution can provide good graft quality after explantation and thus meet the requirements for OCA. For this purpose, human osteochondral allografts of the knee and ankle were analyzed. Live/Dead analysis was performed and glycosaminoglycan, as well as hydroxyproline content, were measured as crucial chondrocyte integrity factors. Furthermore, biomechanical tests focusing on stress relaxation and elastic compression modulus were performed. The critical value of 70% living chondrocytes, which corresponds to a number of 300 cells/mm², was reached after an average of 16 weeks of storage. In addition, a constant cell shrinkage was observed over time. The amount of glycosaminoglycan and hydroxyroline showed a slight and constant decrease over time, but no significant differences when compared from Day 0 to the values at Weeks 40-43. Biomechanical testing also revealed no significant differences at the different time points. Therefore, the results show that the Ringer-based storage solution at 4°C is able to provide a chondrocyte survival of 70% until Week 16. This is comparable to previously published storage solutions. Therefore, the study contributes to the establishment of a Ringer-based osteochondral allograft transplantation system for countries where medium-based storage solution cannot be approved.

Knee Joint Preservation in Tactical Athletes: A Comprehensive Approach Based upon Lesion Location and Restoration of the Osteochondral Unit

The unique physical demands of tactical athletes put immense stress on the knee joint, making these individuals susceptible to injury. In order to ensure operational readiness, management options must restore and preserve the native architecture and minimize downtime, while optimizing functionality. Osteochondral lesions (OCL) of the knee have long been acknowledged as significant sources of knee pain and functional deficits. The management of OCL is predicated on certain injury characteristics, including lesion location and the extent of subchondral disease. Techniques such as marrow stimulation, allograft and autologous chondrocyte implantation are examined in detail, with a focus on their application and suitability in tactical athlete populations. Moreover, the restoration of the osteochondral unit (OCU) is highlighted as a central aspect of knee joint preservation. The discussion encompasses the biomechanical considerations and outcomes associated with various cartilage restoration techniques. Factors influencing procedure selection, including lesion size, location, and patient-specific variables, are thoroughly examined. Additionally, the review underscores the critical role of post-operative rehabilitation and conditioning programs in optimizing outcomes. Strengthening the surrounding musculature, enhancing joint stability, and refining movement patterns are paramount in facilitating the successful integration of preservation procedures. This narrative review aims to provide a comprehensive resource for surgeons, engineers, and sports medicine practitioners engaged in the care of tactical athletes and the field of cartilage restoration. The integration of advanced preservation techniques and tailored rehabilitation protocols offers a promising avenue for sustaining knee joint health and function in this demanding population.

Short-Term Outcomes After Bipolar Osteochondral Allograft Transplantation (OCAT) in the Ankle

Treatment options for symptomatic cartilage loss in the ankle are not consistently effective. This study documents initial outcomes for patients undergoing bipolar OCAT in the ankle after advances in tissue preservation, transplantation techniques, and patient management strategies were implemented. Patients were prospectively enrolled into a registry designed to follow outcomes after OCAT in the ankle. Fourteen patients were included for analyses (12 primary OCAT, 2 revision OCAT). Four patients underwent Bipolar OCAT (tibia, talus) and 10 Bipolar+ OCAT (tibia, talus, fibula). Short-term (median follow-up 43, range 13-73 months) success was documented for 13 patients. Radiographic assessments indicated OCA integration and maintenance of joint space in 12 patients. Statistically significant (p < .030) and clinically meaningful improvements in AAOS and VAS pain scores were noted at 3 months, 6 months, 1 year, and 2 years following OCA transplantation when compared to preoperative measures. For patients that were nonadherent to postoperative restriction and rehabilitation protocols, all 1-year postoperative PROs were significantly lower (p < .050) than for patients who were adherent. The successful outcomes documented in 13 of 14 patients in conjunction with significant and clinically meaningful improvements in patient-reported measures of pain and function support OCA transplantation as an appropriate treatment option in indicated patients. These improvements in outcomes were associated with advances in OCA preservation, preimplantation treatment, transplantation techniques, and patient management strategies, suggesting this shift in practice be considered for OCA transplantation in the ankle.

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.

A Comparison of Treatment of OCD Lesions of the Capitellum With Osteochondral Autograft and Allograft Transplantation

Osteochondritis dissecans (OCD) of the capitellum occurs relatively infrequently but can be found in young overhead-throwing athletes, most commonly in baseball players and gymnasts. Although non-operative management can effectively treat stable lesions, unstable lesions can lead to debilitating symptoms of the elbow and diminished quality of life without surgical intervention. This article reviews methods of treating OCD of the capitellum categorized by stability, size, and patient characteristics, and seeks to familiarize the reader with the appropriate selection of osteochondral allograft versus autograft in treating large, unstable lesions. We complement this review with 3 case examples, each using either an osteochondral autograft or allograft, and discuss the decision-making methodology used in each case.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Responsiveness of Patient-Reported Outcome Measures After Large Knee Articular Cartilage Transplantation: A Systematic Review and Meta-analysis

BACKGROUND

Cartilage transplantation is commonly used to treat large (>4 cm2) articular cartilage defects of the knee. The 2 most common transplants are osteochondral allograft transplantation and autologous chondrocyte implantation. Several patient-reported outcome measures (PROMs) have been used to determine the efficacy of treatment, but it is unknown which measures are the most effective.

PURPOSE

To report the multiple PROMs used after large knee articular cartilage transplantation surgery and to compare the responsiveness between them.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search of the PubMed/MEDLINE and Web of Science databases was performed. A total of 181 articles met inclusion criteria. Patient and study characteristics were extracted, including pre- and postoperative means for PROMs. From the articles that met inclusion criteria for responsiveness analysis (2+ PROMs reported, 1-year minimum follow-up, reported pre- and postoperative means and standard deviations; n = 131), the authors compared the responsiveness between PROM instruments using effect size and relative efficiency (RE) if a PROM could be compared with another in ≥10 articles.

RESULTS

A total of 10,015 patients (10,093 knees; mean age, 34.8 years; mean body mass index, 26.1) were included in this study. The mean follow-up time was 58.3 months (range, 1.5-247.2 months), imaging findings were reported in 80 articles (44.2%), patient satisfaction was reported in 39 articles (21.5%), and range of motion was reported in 10 articles (5.5%). There were 58 unique PROM instruments identified, with the most used being the International Knee Documentation Committee (IKDC) score (n = 118; 65.2%), followed by Knee injury and Osteoarthritis Outcome Score (KOOS) Pain (n = 58; 32.0%), KOOS Sport and Recreation (n = 58; 32.0%), KOOS Quality of Life (n = 57; 31.5%), KOOS Activities of Daily Living (n = 57; 31.5%), and KOOS Symptoms (n = 57; 31.5%). Overall, IKDC was found to have the greatest effect size (1.68) and the best responsiveness of the other PROMs, which include KOOS Pain (RE, 1.38), KOOS Symptoms (RE, 3.06), KOOS Activities of Daily Living (RE, 1.65), KOOS Sport and Recreation (RE, 1.44), Lysholm (RE, 1.76), and Tegner (RE, 1.56).

CONCLUSION

The IKDC is the most responsive PROM after large knee articular cartilage transplantation surgery. The IKDC score is recommended for assessing outcomes after cartilage transplantation surgery.

A systematic review of cartilage procedures for unstable osteochondritis dissecans

OBJECTIVES

Osteochondritis dissecans can result in significant limitations in activity, pain, and early osteoarthritis. There are various treatment modalities to address these defects. The purpose of this study was to provide a qualitative summary of the various treatment options for unstable osteochondritis dissecans in the knee.

METHODS

A literature search was performed on osteochondritis dissecans in the knee using PubMed (MEDLINE), Embase, and Cochrane electronic databases. The search was completed using a combination of the following terms: 'osteochondritis dissecans,' 'OCD,' 'osteochondral,' 'articular cartilage,' 'repair,' 'surgery,' 'treatment,' 'osteochondral allograft,' 'autologous chondrocyte implantation,' 'unstable,' 'knee,' 'clinical studies.'

RESULTS

A total of 682 studies were found, of which 24 were included in the qualitative analysis. The quality score ranged from 46 to 80, and the mean follow-up ranged from 2 to 17 years. The most common surgical procedures were internal fixation (n = 7 studies), ACI (n = 6), fragment excision (n = 3), MACI (n = 2), bone graft + ACI (n = 2), OCA (n = 2), mosaicplasty/OAT (n = 2), and scaffold (n = 2). Overall, the reported outcome measures were heterogeneous in nature. Post-operative International Knee Documentations Committee (IKDC) scores ranged from 75 to 85 and Lysholm scores ranged from 70 to 93.5. Tegner scores ranged from 4 to 5. Rates of failure, complication, and revision were highly variable across studies and surgical techniques.

CONCLUSION

There are a variety of surgical options for the treatment of unstable osteochondritis dissecans. In skeletally immature patients, internal fixation demonstrated acceptable rates of radiographic union and patient reported outcome measures. In skeletally mature patients with large lesions, MACI and OCA transplantation provided similar patient reported outcomes.

Osteochondral Allograft Transplantation in the Shoulder: A Systematic Review of Indications and Outcomes

OBJECTIVE

To collate current literature pertaining to the published reports of indications for, and outcomes of, osteochondral allograft (OCA) transplantations in the shoulder so as to guide surgeons in the management of various etiologies of osteochondral lesions in this joint.

DESIGN

A systematic review of the current literature was performed in February 2022 in the PubMed, Cochrane, and EMBASE databases using specific search terms and predetermined inclusion/exclusion criteria.

RESULTS

One-hundred-twenty-three articles were initially identified, 30 full-text articles were assessed for eligibility, and 17 articles met inclusion criteria. Data were collected for study characteristics, etiology, lesion size/location, intervention/type of graft used, follow-up, and outcomes. In total, 83 shoulders were included (n = 83) in the review with an average follow-up of 45.7 months. Nine specific indications for OCA transplantation in the shoulder included: reverse Hill-Sachs lesions (33), Hill-Sachs lesions (22), pain pump chondrolysis (10), recurrent shoulder instability (7), osteoarthritis/degenerative changes (5), radiofrequency chondrolysis (2), prominent suture anchors (2), glenoid lesion (1), and osteochondritis dissecans (1). Seventeen patients had concomitant surgeries and two patients were lost to follow-up. Of the total 83 shoulders, 68 had favorable outcomes and 13 had unfavorable outcomes as determined by graft incorporation, pain scores, functionality/ROM, patient-reported satisfaction, and/or requirement for revision/arthroplasty. Of the 13 with unfavorable outcomes, a disproportionate number had concomitant surgeries and/or were performed for pain pump chondrolysis (6).

CONCLUSIONS

The use of OCAs appears to be a viable option for a variety of difficult-to-treat shoulder pathologies, particularly those characterized by isolated osteochondral injuries.

Long-term outcomes after osteochondral allograft transplantation to the humeral head

BACKGROUND

Long-term outcomes of osteochondral allograft (OCA) transplantation to the humeral head have been sparsely reported in the literature.

PURPOSE

To evaluate outcomes and survivorship of OCA transplantation to the humeral head in patients with osteochondral defects at a minimum of 10 years of follow-up.

METHODS

A registry of patients who underwent humeral head OCA transplantation between 2004 and 2012 was reviewed. Patients completed pre and postoperative surveys including the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, Short Form 12 (SF-12), and the visual analog scale. Failure was defined by conversion to shoulder arthroplasty.

RESULTS

Fifteen of 21 (71%) patients with a minimum of ten year of follow-up (mean: 14.2 ± 2.40) were identified. Mean patient age was 26.1 ± 8.8 years at the time of transplantation and eight (53%) patients were male. Surgery was performed on the dominant shoulder in 11 of the 15 (73%) cases. The use of local anesthetic delivered via an intra-articular pain pump was the most often reported underlying etiology of chondral injury (n = 9; 60%). Eight (53%) patients were treated with an allograft plug, while seven (47%) patients were treated with a mushroom cap allograft. At final follow-up, mean American Shoulder and Elbow Surgeons (49.9 to 81.1; P = .048) and Simple Shoulder Test (43.1 to 83.3; P = .010) significantly improved compared to baseline. Changes in mean SF-12 physical (41.4 to 48.1; P = .354), SF-12 mental (57.5 to 51.8; P = .354), and visual analog scale (4.0 to 2.8; P = .618) did not reach statistical significance. Eight (53%) patients required conversion to shoulder arthroplasty at an average of 4.8 ± 4.7 years (range: 0.6-13.2). Kaplan-Meier graft survival probabilities were 60% at 10 years and 41% at 15 years.

CONCLUSION

OCA transplantation to the humeral head can result in acceptable long-term function for patients with osteochondral defects. While patient-reported outcomes metrics were generally improved compared to baseline, OCA graft survival probabilities diminished with time. The findings from this study can be used to counsel future patients with significant glenohumeral cartilage injuries and set expectations about the potential for further surgery.

Utility of Talus Osteochondral Allograft Augmentation for Varying Hill-Sachs Lesion Sizes: A Cadaveric Study

Background

Humeral head reconstruction with fresh osteochondral allografts (OCA) serves as a potential treatment option for anatomic reconstruction. More specifically, talus OCA is a promising graft source because of its high congruency with a dense cartilaginous surface.

Purpose

To analyze the surface geometry of the talus OCA plug augmentation for the management of shoulder instability with varying sizes of Hill-Sachs lesions (HSLs).

Study Design

Controlled laboratory study.

Methods

Seven fresh-frozen cadaveric shoulders were tested in this study. The humeral heads were analyzed using actual patients' computed tomography scans. Surface laser scan analysis was performed on 7 testing states: (1) native state; (2) small HSL; (3) talus OCA augmentation for small HSL; (4) medium HSL; (5) talus OCA augmentation for medium HSL; (6) large HSL; and (7) talus OCA augmentation for large HSL. OCA plugs were harvested from the talus allograft and placed in the most medial and superior aspect of each HSL lesion. Surface congruency was calculated as the mean absolute error and the root mean squared error in the distance. A 1-way repeated-measures analysis of variance was performed to evaluate the effects of the difference in the HSL size and associated talus OCA plugs on surface congruency and the HSL surface area.

Results

The surface area analysis of the humeral head with the large (1469 ± 75 mm2), medium (1391 ± 81 mm2), and small (1230 ± 54 mm2) HSLs exhibited significantly higher surface areas than the native state (1007 ± 88 mm2; P < .001 for all sizes). The native state exhibited significantly lower surface areas as compared with after talus OCA augmentation for large HSLs (1235 ± 63 mm2; P < .001) but not for small or medium HSLs. Talus OCA augmentation yielded improved surface areas and congruency after treatment in small, medium, and large HSLs (P < .001).

Conclusion

Talus OCA plug augmentation restored surface area and congruency across all tested HSLs, and the surface area was best improved with the most common HSLs-small and medium.

Clinical Relevance

Talus OCA plugs may provide a viable option for restoring congruity of the shoulder in patients with recurrent anterior glenohumeral instability and an HSL.

Humeral Head Reconstruction With Osteochondral Allograft: Bone Plug Optimization for Hill-Sachs Lesions Using CT-Based Computer Modeling Analysis

Background

Engaging Hill-Sachs lesions (HSLs) pose a significant risk for failure of surgical repair of recurrent anterior shoulder instability. Reconstruction with fresh osteochondral allograft (OCA) has been proposed as a treatment for large HSLs.

Purpose

To determine the optimal characteristics of talus OCA bone plugs in a computer-simulated HSL model.

Study Design

Descriptive laboratory study; Level of evidence, 6.

Methods

Included were 132 patients with recurrent anterior instability with visible HSLs; patients who had multidirectional instability or previous shoulder surgery were excluded. Three-dimensional computed tomography models were constructed, and a custom computer optimization algorithm was generated to maximize bone plug surface area at the most superior apex (superiorization) and minimize its position relative to the most medial margin of the HSL defect (medialization). The optimal number, diameter, medialization, and superiorization of the bone plug(s) were reported. Percentages of restored glenoid track width and conversion from off- to on-track HSLs after bone plug optimization were calculated.

Results

A total of 86 patients were included in the final analysis. Off-track lesions made up 19.7% of HSLs and, of these, the mean bone plug size was 9.9 ± 1.4 mm, with 2.2 mm ± 1.7 mm of medialization and 3.3 mm ± 2.9 mm of superiorization. The optimization identified 21% of HSLs requiring 1 bone plug, 65% requiring 2 plugs, and 14% requiring 3 plugs, with a mean overall coverage of 60%. The mean width of the restored HSLs was 68%, and all off-track HSLs (n = 17) were restored to on-track. A Jenks natural-breaks analysis calculated 3 ideal bone plug diameters of 8 mm (small), 10.4 mm (medium), and 12 mm (large) in order to convert this group of HSLs to on-track.

Conclusion

Using a custom computer algorithm, we have demonstrated the optimal talus OCA bone plug diameters for reconstructing HSLs to successfully restore the HSL track and, on average, 60% of the HSL surface area and 68% of the HSL width.

Clinical Relevance

Reconstructing HSLs with talus OCA is a promising treatment option with excellent fit and restoration of HSLs. This study will help guide surgeons to optimize OCA bone plugs from the humeral head, femoral head, and talus for varying sizes of HSLs.

Effects of Patient Assessment and Education by an Integrated Care Team on Postoperative Adherence and Failure Rates After Osteochondral Allograft and Meniscal Allograft Transplantation in the Knee

Background

Patient nonadherence with prescribed rehabilitation protocols is associated with up to 16 times higher likelihood of treatment failure after osteochondral allograft transplantation (OCA) and meniscal allograft transplantation.

Hypothesis

Patients who completed counseling with an orthopaedic health behavior psychologist as part of an evidence-based shift in practice at our institution would have significantly lower rates of nonadherence and surgical treatment failure versus patients who did not participate in counseling.

Study Design

Cohort study; Level of evidence, 2.

Methods

Patients in a prospective registry who underwent OCA and/or meniscal allograft transplantation between January 2016 and April 2021 were included for analysis when 1-year follow-up data were available. Of 292 potential patients, 213 were eligible for inclusion. Patients were categorized based on whether they participated in the preoperative counseling and postoperative patient management program: no health psych group (n = 172) versus health psych group (n = 41). Nonadherence was defined as documented evidence of a deviation from the prescribed postoperative rehabilitation protocol.

Results

In this cohort of patients, 50 (23.5%) were documented to be nonadherent. Patients in the no health psych cohort were significantly more likely to be nonadherent (P = .023; odds ratio [OR], 3.4). Tobacco use (OR, 7.9), higher preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference score, lower preoperative PROMIS Mental Health score, older age, and higher body mass index were also significantly associated with nonadherence (P < .001 for all). Patients who were nonadherent with the prescribed postoperative rehabilitation protocol during the first year after transplantation were 3 times more likely (P = .004) to experience surgical treatment failure than those who were adherent. Overall, 26.2% of patients in the no health psych group experienced surgical treatment failure versus 12.2% in the health psych cohort.

Conclusion

Data from the present study suggest that preoperative counseling with a health behavior psychologist is associated with an improved rate of patient adherence and a lower proportion of surgical treatment failure after OCA and meniscal allograft transplantation. Patients who remained adherent to the postoperative protocol were 3 times more likely to have a successful short-term (≥1 year) outcome.

Cartilage Repair of the Tibiofemoral Joint With Versus Without Concomitant Osteotomy: A Systematic Review of Clinical Outcomes

Background

The extent to which concomitant osteotomy provides an improvement in clinical outcomes after cartilage repair procedures is unclear.

Purpose

To review the existing literature to compare clinical outcomes of patients undergoing cartilage repair of the tibiofemoral joint with versus without concomitant osteotomy.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by searching PubMed, the Cochrane Library, and Embase to identify studies that directly compared outcomes between cartilage repair of the tibiofemoral joint alone (group A) versus cartilage repair with concomitant osteotomy (high tibial osteotomy [HTO] or distal femoral osteotomy [DFO]) (group B). Studies on cartilage repair of the patellofemoral joint were excluded. The search terms used were as follows: osteotomy AND knee AND ("autologous chondrocyte" OR "osteochondral autograft" OR "osteochondral allograft" OR microfracture). Outcomes in groups A and B were compared based on reoperation rate, complication rate, procedure payments, and patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score [KOOS], visual analog scale [VAS] for pain, satisfaction, and WOMAC).

Results

Included in the review were 5 studies (1 level 2 study, 2 level 3 studies, 2 level 4 studies) with 1747 patients in group A and 520 patients in group B. The mean patient ages were 34.7 and 37.5 years in groups A and B, respectively, and the mean lesion sizes were 4.0 and 4.5 cm², respectively. The mean follow-up time was 44.6 months. The most common lesion location was the medial femoral condyle (n = 999). Preoperative alignment averaged 1.8° and 5.5° of varus in groups A and B, respectively. One study found significant differences between groups in KOOS, VAS, and satisfaction, favoring group B. The reoperation rates were 47.4% and 17.3% in groups A and B, respectively (P < .0001).

Conclusion

Patients undergoing cartilage repair of the tibiofemoral joint with concomitant osteotomy might be expected to experience greater improvement in clinical outcomes with a lower reoperation rate compared with those undergoing cartilage repair alone. Surgeons preparing for cartilage procedures of the knee joint should pay particular attention to preoperative malalignment of the lower extremity to optimize outcomes.

Improving Technical Outcome in Osteochondral Allograft Transplantation of the Femoral Trochlea: The Role of Contoured Guides, Experience Level, Graft Size, and Graft Position

Background

The use of coring instrumentation for osteochondral allograft (OCA) transplantation of the femoral trochlea is challenging due to the complex topography of this anatomical area.

Purpose

We sought to determine the effect of flat guides versus guides contoured to the surface of the trochlea on graft step-off in trochlear OCAs performed on a foam bone model. We also determined the effect of surgeon experience level and graft size on step-off.

Study Design

Controlled laboratory study.

Methods

Allograft harvesters were produced in 3 different sequential sizes with either a flat or a contoured undersurface. The guides matched one another in all aspects of shape and size except for the undersurface contour. The contoured undersurface generally matched the surface of the bone model trochlea but was not customized to that surface. A total of 72 foam femora were obtained. Identical trochlear stellate lesions of 3 different sizes (small, medium, and large) were created using 3-dimensional printed surface templates. A total of 6 surgeons (3 attending and 3 resident surgeons) performed OCAs of each trochlear lesion. Each surgeon performed 1 graft for each size and each guide type (n = 6 per surgeon). A specialized digital caliper was prepared that allowed the measurement of graft step-off to within 0.01 mm at a distance of 5 mm between the 2 sensors. The measurements were performed at 8 positions around the clockface of the grafts.

Results

Grafts performed with the contoured guides had a mean step-off of 0.43 ± 0.37 mm. Grafts performed with the flat guides had a mean step-off of 0.74 ± 0.78 mm (P < .0001). Experience level did not have a significant effect on graft step-off (P = .81). There was no identifiable pattern indicating higher step-off at any one position on the clockface.

Conclusion

In this study, contoured grafts had significantly lower step-offs compared with flat guides. Experience level, clockface position, and graft size did not affect step-off.

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.

Short term clinical outcomes of a Prochondrix® thin laser-etched osteochondral allograft for the treatment of articular cartilage defects in the knee

Objective: The purpose of this study is to evaluate the short-term clinical outcomes of Prochondrix® novel thin, laser-etched osteochondral allograft on isolated articular cartilage defects. Methods: Eighteen patients with isolated, symptomatic, full-thickness articular cartilage lesions were treated with marrow stimulation followed by placement of a T-LE allograft. Demographic and intra-operative data was recorded as well as pre- and post-operative International Knee Documentation Committee (IKDC), Short Form-36 (SF-36), Knee Injury and Osteoarthritis Outcome Score (KOOS), Visual Analogue Scale (VAS) and Tegner scores. Pre- and post-operative data was compared at 6, 12, 24 and 36 months post operatively. Failures requiring reoperation were also recorded. Results: At a mean follow-up of 2.5 years (6-43 months), VAS decreased from 6.55 to 2.55 (p = .02) and subjective IKDC scores increased from 37.61 to 59.65 (p = .02). Statistically significant increases were also seen in KOOS Function-Sports and Recreational Activities (+26.04, p = .04) and KOOS QOL (+18.76, p = .007) as well as in SF-36 Physical Functioning (+25.20, p = .04), Energy/Fatigue (+16.50, p = .02), Social Functioning (+11.79, p = .04), and Bodily Pain (+25.18, p = .04). There were two failures requiring reoperation: one conversion to a patellofemoral arthroplasty (PFA), and one graft dislodgement which required removal. Conclusion: Treatment of articular cartilage lesions of the knee with ProChondrix® has demonstrated sustained positive results out to a mean follow-up of two and a half years in this prospective case series with a low failure rate that required reoperation (2 patients) in this series. These results are comparable to the short-term results of other cartilage restoration procedures currently in use today. A meta-analysis of osteochondral allografting demonstrated a mean 86.7% survival rate at 5 years with significant improvements in clinical outcome scores reaching MCID values.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

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

RESULTS

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

CONCLUSION

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

Anatomic Factors Associated With Osteochondral Allograft Matching for Trochlear Cartilage Defects: A Computer-Simulation Study

BACKGROUND

Articular step-off between the donor and recipient in osteochondral allograft transplant has been shown to alter contact pressures. Currently, commercial allograft donor selection is primarily based on simple anatomic parameters such as trochlear length, trochlear width, and tibial width.

PURPOSE

To identify anatomic factors associated with optimal graft matching by using a 3-dimensional simulation model.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Computed tomography images of 10 cadaveric trochlear specimens were obtained to generate 3-dimensional models. Circular defects were created virtually in the recipient trochleae at both superolateral (18.0 mm and 22.5 mm) and central (18.0 mm, 22.5 mm, 30.0 mm) locations. The donor models were virtually projected onto the defect models, and the most optimal graft from any location of the donor specimen was selected. Cartilage incongruity, subchondral bone incongruity, and peripheral articular step-off were calculated for each graft-defect combination. Linear regression models were generated to identify predictors of incongruity, step-off, and the effect of sulcus and sagittal angle mismatch. Akaike information criterion-driven stepwise regression models were generated to identify multivariate predictors.

RESULTS

Ideal matches were found for 100% of superolateral defects but for only 15% to 53% of central defects, depending on the defect size. Multivariate stepwise regression identified laterality (odds ratio [OR], 0.54; P = .081), sulcus angle (OR, 0.79; P < .001), sagittal angle (OR, 0.83; P = .001), lateral radius of curvature (OR, 0.81; P < .001), and medial facet width (OR, 0.86; P = .155) as predictors of ideal graft matching. In central defects with proud grafts, increasing sagittal angle and sulcus angle resulted in significantly (P < .001) increased articular step-off, which became sequentially larger with defect size.

CONCLUSION

Sagittal angle, sulcus angle, and lateral radius of curvature mismatch should be used to determine optimal donor allografts, especially in the setting of large (30-mm) central defects. Increasing sulcus angle and sagittal angle mismatch correlated with increasing step-off in proud grafts, whereas sulcus angle and sagittal angle inconsistently correlated with step-off in recessed grafts.

CLINICAL RELEVANCE

Additional descriptive trochlear measurements should be incorporated into the algorithm for donor selection. These findings can be used to identify acceptable mismatch parameters.

Chondrocyte morphology as an indicator of collagen network integrity

Osteochondral allograft (OCA) transplantation offers an attractive treatment option as it can be used to repair large cartilage defects that otherwise would not heal. The currently accepted criterion for OCA selection for joint reconstruction is the percentage of viable chondrocytes, but this criterion alone may not be sufficient to ensure structural integrity and functional performance of allografts following transplantation. We sought to determine an additional parameter that indicates matrix integrity. We used multi-photon microscopy to quantitatively assess chondrocyte viability, chondrocyte shape, and collagen structure of articular cartilage of OCAs. Chondrocyte shape varied considerably in otherwise macroscopically healthy-looking OCAs with good (>90%) cell viability. Shape varied from the expected ellipsoidal form found in healthy cartilage, to excessively elongated and flattened cells that often contained multiple cytoplasmic processes reminiscent of those observed in fibroblasts. Chondrocytes with abnormal morphology were associated with degradation of their pericellular matrix and disruption of the collagen fiber orientation, reflected by an increase in heterogeneity of second harmonic signal intensity. Cell shape may be an important marker for collagen network integrity in articular cartilage in general and OCAs specifically. We propose that, aside from cell viability, cell shape may be used as an additional criterion measure for the selection of OCAs. OCAs selected for transplantation based on these criteria showed good graft-host integration post-operation. In view of the rapid and nondestructive nature of the current approach, it may be suitable for clinical application in the future.

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.

Mood Disorders Are Associated with Increased Perioperative Opioid Usage and Health Care Costs in Patients Undergoing Knee Cartilage Restoration Procedure

OBJECTIVE

To identify the prevalence of mood disorder diagnoses in patients undergoing cartilage transplantation procedures and determine the relationship between mood disorders, opioid usage, and postoperative health care costs.

DESIGN

Patients with current procedural terminology (CPT) codes for osteochondral autograft transplantation (OAT), osteochondral allograft transplantation (OCA), and autologous chondrocyte implantation (ACI) were identified in the Truven Health Marketscan database (January 2009-September 2014). Patients were grouped based on having a preoperative mood disorder diagnosis (preMDD). Preoperative opioids, postoperative opioids ≥90 days, and health care costs within the year postoperative were compared for those with and without mood disorders. Costs were analyzed, adjusting for preoperative cost, sex, age, and opioid usage, for those with and without mood disorders.

RESULTS

A total of 3,682 patients were analyzed (ACI: 690, OAT: 1,294, OCA: 1,698). A quarter of patients had preMDD (ACI: 25.4%, OAT: 20.6%, OCA: 22.7%). Postoperative opioid use was more prevalent in preMDD patients (OAT: 37.1% vs. 24.1%, P < 0.001; OCA: 30.4% vs. 24.8%, P = 0.032; ACI: 33.7% vs. 26.2%, P = 0.070) (odds ratio [OR] ranged from 1.29 to 1.86). First-year postoperative log-transformed costs were significantly greater for preMDD patients (ACI: $7,733 vs. $5,689*, P = 0.012; OAT: $5,221 vs. $3,823*, P < 0.001; OCA: $6,973 vs. $3,992*, P < 0.001; *medians reported). The estimated adjusted first postoperative year cost increase for preMDD OCA patients was 41.7% (P < 0.001) and 28.0% for OAT patients (P = 0.034). There was no statistical difference for ACI patients (P = 0.654).

CONCLUSION

Cartilage transplantation patients have a high prevalence of preoperative mood disorders. Opioid use and health care costs were significantly greater for patients with preoperative mood disorder diagnoses.

LEVEL OF EVIDENCE

Level III, retrospective therapeutic study.

Bipolar Cartilage Lesions of the Knee: A Systematic Review of Techniques, Outcomes, and Complications

OBJECTIVE

The purpose of this systematic review was to determine (1) treatment options for bipolar cartilage lesions of the knee, (2) patient-reported outcomes following various surgical treatments, and (3) complication and failure rates following surgery.

DESIGN

A literature search of PubMed, the Cochrane Library, and CINHAL was performed using PRISMA guidelines. Patients were included if they had bipolar cartilage lesions of the knee treated surgically. Lesion characteristics, surgical technique, patient-reported outcomes, complication rates, failure rates, and survivorship were recorded.

RESULTS

Fourteen studies yielded 301 knees treated surgically. Patient age ranged from 15 to 74 years. Surgical techniques included 138 autologous chondrocyte implantation (ACI), 156 osteochondral allograft transplantation (OCA), and 7 osteochondral autograft transfer system (OATS). Seven studies reported a concomitant procedure rate that ranged from 0% to 88%. Eight studies reported that both reciprocal lesions received surgical treatment, while 6 studies did not specify. Lesion size ranged from 1 to 41 cm². All reported postoperative improvements in patient-reported outcomes, but the measures were very heterogeneous. There were no major complications and the rate of minor complications ranged from 0% to 50%. Survivorship ranged from 40% to 100% for OCA, 76% to 95% for ACI, and 100% for the 1 study evaluating OATS.

CONCLUSIONS

Bipolar cartilage lesions of the knee typically involve a large surface area and are most commonly treated with ACI or OCA, while OATS may be an option for smaller lesions. Improvements in mid-term patient-reported outcomes were reported for all surgical procedures and they can be performed safely with a low rate of major complications.

Tibial Plateau Cartilage Lesions: A Systematic Review of Techniques, Outcomes, and Complications

OBJECTIVE

The purpose of this systematic review is to determine (1) current reported treatment options for isolated tibial plateau (TP) cartilage lesions, (2) patient reported outcomes following various treatments, and (3) complication rate and survivorship following various treatments.

DESIGN

A literature search of PubMed, the Cochrane Library, and CINAHL was conducted adhering to PRISMA guidelines. Patients were included if they had TP cartilage lesions treated with surgery. Lesion characteristics, surgical procedure details, patient reported outcomes, complication, and failure rates were collected.

RESULTS

Thirteen studies yielded 205 knees with TP cartilage lesions treated surgically. Ages ranged from 12 to 77 years. Surgical techniques included 138 treated with osteochondral allograft transplantation (OCA), 37 treated with osteochondral autograft transfer system (OATS), 11 treated with microfracture, 11 treated with an osteochondral scaffold, and 8 treated with autologous chondrocyte implantation (ACI). The patient-reported outcome measures were heterogeneous, but all reported improvements with the notable exception of one study evaluating microfracture. The rate of complications ranged from 0% to 4.6%. Failure rate ranged from 22% to 46% for OCA and 0% to 16% for OATS. No failures were reported for the additional techniques.

CONCLUSIONS

Various surgical techniques have been utilized for the treatment of TP cartilage lesions. Patient-reported outcome measures were heterogeneous, but improvements were reported following all surgical treatments except for microfracture, which resulted in decreased scores at mid-term follow-up. The complication rate was low for all techniques described. However, the failure rate was higher following unicondylar OCA for salvage treatment of posttraumatic deformities.

Effect of Graft-Host Interference Fit on Graft Integration after Osteochondral Allograft Transplantation: A Comparative MRI Analysis of Two Instrumentation Sets

OBJECTIVE

Precise graft-host interference fit is a potentially import factor for the successful incorporation of osteochondral allograft (OCA) transplants for the treatment of symptomatic focal cartilage defects. It was hypothesized that selection of OCA plug instrumentation set has a significant effect on graft integration and morphology after OCA transplantation.

METHODS

Thirty-one patients who underwent OCA transplantation between July 2013 and July 2016 were identified for this comparative magnetic resonance imaging (MRI) analysis. Patients were stratified into two groups based on the treatment with the Arthrex Allograft OATS Instrument Set or the JRF Ortho Osteochondral Allograft Plug Instrumentation. MRI was obtained at 12 months postoperatively. All grafts were assessed for integration using the Osteochondral Allograft MRI Scoring System (OCAMRISS), host marrow edema size, graft-host interface distance, graft cartilage integrity, cyst size, graft contour and presence of effusion.

RESULTS

At a mean follow-up of 11.39 ± 1.98 months, 95.5% of all grafts showed osseous integration into the recipient bone with 68.2% presenting without cystic changes of the graft or host-graft junction. No differences were seen in any OCAMRISS subscale besides cartilage signal, which demonstrated minimal differences (P = 0.046).

CONCLUSION

OCAs show excellent osseous integration at the graft-host junction at 12 months postoperatively. The comparative MRI analysis of two instrumentation sets yielded no significant differences in terms of graft integration, bone marrow edema, or cystic formation. Hence, this study cannot recommend one instrumentation set over the other. Consequently, the individual preference should guide the surgeon's selection of instrumentation for OCA transplantation.

Differences in the Demographics and Preferred Management of Knee Cartilage Injuries in Soccer Players Across FIFA Centers of Excellence

OBJECTIVE

We sought to report on the demographics and epidemiology of knee cartilage injuries and preferred management in soccer players, across FIFA Medical Centers of Excellence (FMCE).

DESIGN

A descriptive questionnaire focusing on characteristics of knee cartilage injuries and their management in soccer players during the 10-year period prior to the distribution of the questionnaire was sent to all FMCE around the world in September 2019 via an online platform. Voluntary responses from centers were processed and analyzed. Descriptive characteristics were reported using median and interquartile ranges (IQR) for continuous variables and frequencies and percentages (%) for discrete variables.

RESULTS

A total of 15 centers from 5 continents responded to the questionnaire and reported on a total of 4526 soccer players. Among centers, the median age was 27 years (IQR: 23-38), the median rate of male players was 75% (IQR: 68-90), and the median rate of professional players was 10% (IQR: 5-23). The most common reported etiology for cartilage injury was traumatic (median 40%, IQR: 13-73). The most common nonoperative treatment utilized was physical therapy (median 90%, IQR: 51%-100%) and the most common operative treatment utilized was bone marrow stimulation/micro-fracture (median 40%, IQR: 19-54%). The utilization of other cartilage restoration procedures varied across centers.

CONCLUSIONS

Our findings highlight different tendencies in the management of these injuries across FMCE and emphasize the need for collaborative efforts focusing on establishing consensus guidelines for the optimal management of these challenging injuries in soccer players.

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.

Concomitant Osteotomy Reduces Risk of Reoperation Following Cartilage Restoration Procedures of the Knee: A Matched Cohort Analysis

OBJECTIVE

The objective of this study is to compare the (1) reoperation rates, (2) 30-day complication rates, and (3) cost differences between patients undergoing isolated autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA) procedures alone versus patients with concomitant osteotomy.

STUDY DESIGN

Retrospective cohort study, level III.

DESIGN

Patients who underwent knee ACI (Current Procedural Terminology [CPT] 27412) or OCA (CPT 27415) with minimum 2-year follow-up were queried from a national insurance database. Resulting cohorts of patients that underwent ACI and OCA were then divided into patients who underwent isolated cartilage restoration procedure and patients who underwent concomitant osteotomy (CPT 27457, 27450, 27418). Reoperation was defined by ipsilateral knee procedure after the index surgery. The 30-day postoperative complication rates were assessed using ICD-9-CM codes. The cost per patient was calculated.

RESULTS

A total of 1,113 patients (402 ACI, 67 ACI + osteotomy, 552 OCA, 92 OCA + osteotomy) were included (mean follow-up of 39.0 months). Reoperation rate was significantly higher after isolated ACI or OCA compared to ACI or OCA plus concomitant osteotomy (ACI 68.7% vs. ACI + osteotomy 23.9%; OCA 34.8% vs. OCA + osteotomy 16.3%). Overall complication rates were similar between isolated ACI (3.0%) and ACI + osteotomy (4.5%) groups and OCA (2.5%) and OCA + osteotomy (3.3%) groups. Payments were significantly higher in the osteotomy groups at day of surgery and 9 months compared to isolated ACI or OCA, but costs were similar by 2 years postoperatively.

CONCLUSIONS

Concomitant osteotomy at the time of index ACI or OCA procedure significantly reduces the risk of reoperation with a similar rate of complications and similar overall costs compared with isolated ACI or OCA.

Do Self-Reported Drug Allergies Influence Clinically Significant Outcome Improvement Following Osteochondral Allograft Transplantation? A Nested Cohort Study

OBJECTIVE

To compare clinical outcomes for patients who underwent osteochondral allograft transplantation (OCA) based on the presence or absence of one or more self-reported drug allergies.

DESIGN

Prospective data were collected from 245 consecutive patients after OCA of the knee from one large academic institution. Patient-reported allergies were obtained via chart review. Patient-reported outcome measures, including activities of daily living of the Knee Outcome Survey (KOS-ADL), Marx Activity Scale, International Knee Documentation Committee (IKDC), and visual analogue scale (VAS) pain were all collected. The minimal clinically important difference (MCID) for each outcome was quantified using a distribution-based method. Independent t tests were used to compare patient-reported outcome measures between those with and without self-reported allergies, while chi-square analysis of association was used to compare rates of MCID achievement.

RESULTS

Of 245 patients included, 83 (33.9%) reported having at least one drug allergy at the time of OCA. There were no statistically significant differences with regard to patient demographics, including age, body mass index, gender, or sports participation between those with and without a reported allergy. Similarly, there were no significant differences found between baseline preoperative patient-reported outcomes. Overall, both cohorts demonstrated a significant improvement from baseline scores at 2 years postoperatively. There were no differences found between any patient-reported outcome at 2 years postoperatively. The presence of at least one self-reported drug allergy was not a significant risk factor for failing to achieve the MCID in any specific outcome measure.

CONCLUSIONS

The presence of one or more drug allergy was not associated with worse patient-reported outcomes or lower rates of clinically significant outcome improvement after OCA.

High Return to Sport in Patients Over 45 Years of Age Undergoing Osteochondral Allograft Transplantation for Isolated Chondral Defects in the Knee

OBJECTIVE

The purpose of this study was to evaluate the efficacy of osteochondral allograft (OCA) in patients older than 45 years of age, particularly with respect to return to sport.

DESIGN

A retrospective review was performed to evaluate patients greater than 45 who underwent an OCA for a symptomatic osteochondral defect of the knee between June 2011 and January 2019.

RESULTS

Overall, there were 18 patients (76% male) that met our inclusion and exclusion criteria. Follow-up was attained in 14 of these patients (78%). The mean age of patients included was 52.6 years (48-57) with a mean of 37 months of follow-up (18-60). Visual Analogue Scale scores decreased significantly from the preoperative baseline to final follow-up (7.7 ± 1.7 vs. 2.0 ± 2.0, P < 0.01). Furthermore, the mean Visual Analogue Scale while playing sport was 3.4 ± 3.2, and the mean Knee Injury and Osteoarthritis Outcome Score was 77.5 ± 12.7 at final follow-up. Overall, 11 patients (78.6%) were able to return to their desired sport. No clinical failures were identified during the follow-up period.

CONCLUSION

In our series of patients 45 years and older who were treated with OCA for focal osteochondral injuries of the knee, we found a significant improvement in clinical outcome scores at a midterm follow-up of 37 months with no revision OCA procedures or conversion to any form of knee arthroplasty. In addition, a high percentage of patients were able to return to their preferred level of athletic activity.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Comparison of Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation of the Knee in a Large Insurance Database: Reoperation Rate, Complications, and Cost Analysis

OBJECTIVE

To compare (1) the reoperation rates, (2) risk factors for reoperation, (3) 30-day complication rates, and (4) cost differences between autologous chondrocyte implantation (ACI) and osteochondral allograft transplantation (OCA) of the knee in a large insurance database.

DESIGN

Subjects who underwent knee ACI (Current Procedural Terminology [CPT] code 27412) or OCA (CPT code 27415) with minimum 2-year follow-up were queried from a national insurance database. Reoperation was defined by ipsilateral knee procedure after index surgery. Multivariate logistic regression models were built to determine the effect of independent variables (age, sex, tobacco use, obesity, diabetes, and concomitant osteotomy) on reoperation rates. The 30-day complication rates were assessed using ICD-9-CM codes. The cost of the procedures per patient was calculated. Statistical comparisons were made. All P values were reported with significance set at P < 0.05.

RESULTS

A total of 909 subjects (315 ACI and 594 OCA) were included (mean follow-up 39.2 months). There was a significantly higher reoperation rate after index ACI compared with OCA (67.6% vs. 40.4%, P < 0.0001). Concomitant osteotomy at the time of index procedure significantly reduced the risk for reoperation in both groups (odds ratio [OR] 0.2, P < 0.0001 and OR 0.2, P = 0.009). The complication rates were similar between ACI (1.6%) and OCA (1.2%) groups (P = 0.24). Day of surgery payments were significantly higher after ACI compared with OCA (P = 0.013).

CONCLUSIONS

Autologous chondrocyte implantation had significantly higher reoperation rates and cost with similar complication rates compared with OCA. Concomitant osteotomy significantly reduced the risk for reoperation in both groups.

Does the Symmetry of Patellar Morphology Matter When Matching Osteochondral Allografts for Osteochondral Defects Involving the Central Ridge of the Patella?

OBJECTIVE

The purpose of this study was to determine if differences in Wiberg classification play a role in the ability of donor patellar osteochondral allografts to match the native patellar surface when treating osteochondral defects of the patellar apex.

DESIGN

Twenty (10 Wiberg I and 10 Wiberg II/III) human patellae were designated as the recipient. Each recipient was size-matched to both a Wiberg I and a Wiberg II/III patellar donor. A 16-mm circular osteochondral "defect" was created on the central ridge of the recipient patella. The randomly ordered donor Wiberg I or Wiberg II/III plug was harvested from a homologous location and transplanted into the recipient. The recipient was then nano-CT (computed tomography) scanned, digitally reconstructed, registered to the initial nano-CT scan of the recipient patella, and processed to determine root mean squared circumferential step-off heights as well as surface height deviation. The process was then repeated for the other allograft plug.

RESULTS

There was no significant difference in mean step-off height between matched and unmatched Wiberg plugs; however, there was a statistically significant difference in surface height deviation over the whole surface (0.50 mm and 0.64 mm respectively, P = 0.03). This difference of 0.14 mm is not felt to be clinically significant. Tibial width was correlated to patellar width (r = 0.82) and patellar height (r = 0.68).

CONCLUSIONS

For osteochondral allograft sizes up to 16 mm there appears to be no advantage to match donor and recipient patellar morphology. Further study is warranted to evaluate defects requiring larger graft sizes.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

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.

Effect of Preoperative Imaging and Patient Factors on Clinically Meaningful Outcomes and Quality of Life After Osteochondral Allograft Transplantation: A Machine Learning Analysis of Cartilage Defects of the Knee

BACKGROUND

Fresh osteochondral allograft transplantation (OCA) is an effective method of treating symptomatic cartilage defects of the knee. This restoration technique involves the single-stage implantation of viable, mature hyaline cartilage into a chondral or osteochondral lesion. The extent to which preoperative imaging and patient factors predict achieving clinically meaningful outcomes among patients undergoing OCA for cartilage lesions of the knee remains unknown.

PURPOSE

To determine the predictive relationship of preoperative imaging, preoperative patient-reported outcome measures (PROMs), and patient demographics with achievement of the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) for functional and quality-of-life PROMs at 2 years after OCA for symptomatic cartilage defects of the knee.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were analyzed for patients who underwent OCA before May 1, 2018, by 2 high-volume fellowship-trained cartilage surgeons. The International Knee Documentation Committee (IKDC) subjective form, Knee Outcome Survey-Activities of Daily Living (KOS-ADL), and mental and physical component summaries of the SF-36 were administered preoperatively and at 2 years postoperatively. A total of 42 predictive models were created using 7 unique architectures to detect achievement of the MCID for each of the 4 outcome measures and the SCB for the IKDC and KOS-ADL. Data inputted into the models included sex, age, body mass index, baseline PROMs, lesion size, concomitant ligamentous or meniscal tear, and presence of "bone bruise" or osseous edema. Shapley additive explanations plot analysis identified predictors of reaching the MCID and SCB.

RESULTS

Of the 185 patients who underwent OCA for the knee and met eligibility criteria from an institutional cartilage registry, 153 (83%) had 2-year follow-up. Preoperative magnetic resonance imaging (MRI), baseline PROMs, and patient demographics best predicted reaching the 2-year MCID and SCB of the IKDC and KOS-ADL PROMs, with areas under the receiver operating characteristic curve of the top-performing models ranging from good (0.88) to excellent (0.91). MRI faired poorly (areas under the curve, 0.60-0.68) in predicting the MCID for the mental and physical component summaries. Higher body mass index, knee malalignment, absence of preoperative osseous edema, concomitant anterior cruciate ligament or meniscal injury, larger defect size, and the implantation of >1 OCA graft were consistent findings contributing to failure to achieve the MCID or SCB at 2 years postoperatively.

CONCLUSION

Our machine learning models demonstrated that preoperative MRI, baseline PROMs, and patient demographics reliably predict the ability to reach clinically meaningful thresholds for functional knee outcomes 2 years after OCA for cartilage defects. Although clinical improvement in knee function can be reliably predicted, improvements in quality of life after OCA depend on a comprehensive preoperative assessment of the patient's perception of his or her mental and physical health. Absence of osseous edema, concomitant anterior cruciate ligament or meniscal injury, larger lesion size on MRI, knee malalignment, and elevated body mass index are predictive of failure to achieve 2-year functional benefits after OCA of the knee.

Preoperative Grades of Osteoarthritis and Meniscus Volume Correlate with Clinical Outcomes of Osteochondral Graft Treatment for Cartilage Defects in the Knee

OBJECTIVE

To identify preoperative imaging-based indicators of knee degeneration that correlate with graft failure risk and postoperative clinical outcome scores after osteochondral graft treatment for chondral defects of the knee.

DESIGN

Prospectively collected data from 113 patients (mean age, 34 years; 65% male) treated with mosaicplasty or osteochondral allograft transplantation (OCA) was reviewed. Four different aspects of knee degeneration were examined based on preoperative radiographs or magnetic resonance imaging: (1) Osteoarthritis using the Kellgren-Lawrence (KL) grading system, (2) meniscus volume, (3) meniscus quality, and (4) synovitis. Primary outcomes included graft failure, defined by removal/revision of the graft or conversion to arthroplasty, and patient responses to clinical outcome scores.

RESULTS

Forty-one knees (36%) underwent mosaicplasty, and 72 knees (64%) underwent OCA. Mean duration of follow-up was 4.5 years (range, 2-14 years). A preoperative KL grade of ≥3 was correlated with increased failure rates (P = 0.01), lower postoperative International Knee Documentation Committee form (IKDC), Activities of Daily Living of the Knee Outcome Survey (KOS-ADL), and Overall Condition scores (P < 0.01), and decreased improvement in Overall Condition scores (P = 0.01). Within an individual tibiofemoral compartment, a preoperative meniscus volume grade of ≥3 (indicating <50% meniscus volume remaining) was correlated with increased condylar graft failure rates (P < 0.01). Preoperative meniscus quality and synovitis grades were not associated with graft failure rates or clinically meaningful differences in postoperative outcome scores.

CONCLUSIONS

Greater preoperative osteoarthritis and meniscus volume loss were correlated with increased graft failure rates after osteochondral graft treatment for chondral defects 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.

Overlapping Allografts Provide Superior and More Reliable Surface Topography Matching Than Oblong Allografts: A Computer-Simulated Model Study

BACKGROUND

Osteochondral allograft transplantation is 1 treatment option for focal articular cartilage defects of the knee. Large irregular defects, which can be treated using an oblong allograft or multiple overlapping allografts, increase the procedure's technical complexity and may provide suboptimal cartilage and subchondral surface matching between donor grafts and recipient sites.

PURPOSE

To quantify and compare cartilage and subchondral surface topography mismatch and cartilage step-off for oblong and overlapping allografts using a 3-dimensional simulation model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human cadaveric medial femoral hemicondyles (n = 12) underwent computed tomography and were segmented into cartilage and bone components using 3-dimensional reconstruction and modeling software. Segments were then exported into point-cloud models. Modeled defect sizes of 17 × 30 mm were created on each recipient hemicondyle. There were 2 types of donor allografts from each condyle utilized: overlapping and oblong. Grafts were virtually harvested and implanted to optimally align with the defect to provide minimal cartilage surface topography mismatch. Least mean squares distances were used to measure cartilage and subchondral surface topography mismatch and cartilage step-off.

RESULTS

Cartilage and subchondral topography mismatch for the overlapping allograft group was 0.27 ± 0.02 mm and 0.80 ± 0.19 mm, respectively. In comparison, the oblong allograft group had significantly increased cartilage (0.62 ± 0.43 mm; P < .001) and subchondral (1.49 ± 1.10 mm; P < .001) mismatch. Cartilage step-off was also found to be significantly increased in the oblong group compared with the overlapping group (P < .001). In addition, overlapping allografts more reliably provided a significantly higher percentage of clinically acceptable (0.5- and 1-mm thresholds) cartilage surface topography matching (overlapping: 100% for both 0.5 and 1 mm; oblong: 90% for 1 mm and 56% for 0.5 mm; P < .001) and cartilage step-off (overlapping: 100% for both 0.5 and 1 mm; oblong: 86% for 1 mm and 12% for 0.5 mm; P < .001).

CONCLUSION

This computer simulation study demonstrated improved topography matching and decreased cartilage step-off with overlapping osteochondral allografts compared with oblong osteochondral allografts when using grafts from donors that were not matched to the recipient condyle by size or radius of curvature. These findings suggest that overlapping allografts may be superior in treating large, irregular osteochondral defects involving the femoral condyles with regard to technique.

CLINICAL RELEVANCE

This study suggests that overlapping allografts may provide superior articular cartilage surface topography matching compared with oblong allografts and do so in a more reliable fashion. Surgeons may consider overlapping allografts over oblong allografts because of the increased ease of topography matching during placement.

Unicompartmental bipolar osteochondral and meniscal allograft transplantation is effective for treatment of medial compartment gonarthrosis in a canine model

Osteochondral allograft (OCA) transplantation can restore large articular defects in the knee. Bipolar OCA transplantations for partial and whole joint resurfacing often have less favorable results than single-surface transplants. This study was designed to use a large animal model to test the hypothesis that unicompartmental bipolar osteochondral and meniscal allograft transplantation (BioJoint) would be as or more effective for treatment of medial compartment osteoarthritis (OA) compared to standard-of-care nonoperative treatment. OA was induced in one knee of each research hound (n = 8) using a meniscal release model and pretreatment assessments were performed. After 3 months, dogs were randomly assigned to either the control group (n = 4, no surgical intervention, daily nonsteroidal antiinflammatory drugs [NSAIDs]) or the BioJoint group (n = 4). Clinical, radiographic, and arthroscopic assessments were performed longitudinally and histopathology was evaluated at the 6-month endpoint. At study endpoint, functional, pain, and total pressure index measures, as well as radiographic and arthroscopic grading of graft appearance and joint health, demonstrated superior outcomes for BioJoints compared to NSAID controls. Furthermore, histologic assessments showed that osteochondral and meniscal transplants maintain integrity and integrated into host tissues. Clinical significance: The results support the safety and efficacy of unicompartmental bipolar osteochondral and meniscal allograft transplantation in a preclinical model with highly functional outcomes without early OA progression.

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.

Association Between Preoperative Mental Health and Clinically Meaningful Outcomes After Osteochondral Allograft for Cartilage Defects of the Knee: A Machine Learning Analysis

BACKGROUND

Fresh osteochondral allograft transplantation (OCA) is an effective method of treating symptomatic cartilage defects of the knee. This cartilage restoration technique involves the single-stage implantation of viable, mature hyaline cartilage into the chondral or osteochondral lesion. Predictive models for reaching the clinically meaningful outcome among patients undergoing OCA for cartilage lesions of the knee remain under investigation.

PURPOSE

To apply machine learning to determine which preoperative variables are predictive for achieving the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) at 1 and 2 years after OCA for cartilage lesions of the knee.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were analyzed for patients who underwent OCA of the knee by 2 high-volume fellowship-trained cartilage surgeons before May 1, 2018. The International Knee Documentation Committee questionnaire (IKDC), Knee Outcome Survey-Activities of Daily Living (KOS-ADL), and Mental Component (MCS) and Physical Component (PCS) Summaries of the 36-Item Short Form Health Survey (SF-36) were administered preoperatively and at 1 and 2 years postoperatively. A total of 84 predictive models were created using 7 unique architectures to detect achievement of the MCID for each of the 4 outcome measures and the SCB for the IKDC and KOS-ADL at both time points. Data inputted into the models included previous and concomitant surgical history, laterality, sex, age, body mass index (BMI), intraoperative findings, and patient-reported outcome measures (PROMs). Shapley Additive Explanations (SHAP) analysis identified predictors of reaching the MCID and SCB.

RESULTS

Of the 185 patients who underwent OCA for the knee and met eligibility criteria from an institutional cartilage registry, 135 (73%) patients were available for the 1-year follow-up and 153 (83%) patients for the 2-year follow-up. In predicting outcomes after OCA in terms of the IKDC, KOS-ADL, MCS, and PCS at 1 and 2 years, areas under the receiver operating characteristic curve (AUCs) of the top-performing models ranged from fair (0.72) to excellent (0.94). Lower baseline mental health (MCS), higher baseline physical health (PCS) and knee function scores (KOS-ADL, IKDC Subjective), lower baseline activity demand (Marx, Cincinnati sports), worse pain symptoms (Cincinnati pain, SF-36 pain), and higher BMI were thematic predictors contributing to failure to achieve the MCID or SCB at 1 and 2 years postoperatively.

CONCLUSION

Our machine learning models were effective in predicting outcomes and elucidating the relationships between baseline factors contributing to achieving the MCID for OCA of the knee. Patients who preoperatively report poor mental health, catastrophize pain symptoms, compensate with higher physical health and knee function, and exhibit lower activity demands are at risk for failing to reach clinically meaningful outcomes after OCA of the knee.

Return to Sport After Large Single-Surface, Multisurface, or Bipolar Osteochondral Allograft Transplantation in the Knee Using Shell Grafts

Background:

Return to sport (RTS) after osteochondral allograft (OCA) transplantation for large unipolar femoral condyle defects has been consistent, but many athletes are affected by more severe lesions.

Purpose:

To examine outcomes for athletes who have undergone large single-surface, multisurface, or bipolar shell OCA transplantation in the knee.

Study Design:

Case series; Level of evidence, 4.

Methods:

Data from a prospective OCA transplantation registry were assessed for athletes who underwent knee transplantation for the first time (primary transplant) between June 2015 and March 2018 for injury or overuse-related articular defects. Inclusion criteria were preinjury Tegner level ≥5 and documented type and level of sport (or elite unit active military duty); in addition, patients were required to have a minimum of 1-year follow-up outcomes, including RTS data. Patient characteristics, surgery type, Tegner level, RTS, patient-reported outcome measures (PROMs), compliance with rehabilitation, revisions, and failures were assessed and compared for statistically significant differences.

Results:

There were 37 included athletes (mean age, 34 years; range, 15-69 years; mean body mass index, 26.2 kg/m²; range, 18-35 kg/m²) who underwent large single-surface (n = 17), multisurface (n = 4), or bipolar (n = 16) OCA transplantation. The highest preinjury median Tegner level was 9 (mean, 7.9 ± 1.7; range, 5-10). At the final follow-up, 25 patients (68%) had returned to sport; 17 (68%) returned to the same or higher level of sport compared with the highest preinjury level. The median time to RTS was 16 months (range, 7-26 months). Elite unit military, competitive collegiate, and competitive high school athletes returned at a significantly higher proportion (P < .046) than did recreational athletes. For all patients, the Tegner level at the final follow-up (median, 6; mean, 6.1 ± 2.7; range, 1-10) was significantly lower than that at the highest preinjury level (P = .007). PROMs were significantly improved at the final follow-up compared with preoperative levels and reached or exceeded clinically meaningful differences. OCA revisions were performed in 2 patients (5%), and failures requiring total knee arthroplasty occurred in 2 patients (5%), all of whom were recreational athletes. Noncompliance was documented in 4 athletes (11%) and was 15.5 times more likely (P = .049) to be associated with failure or a need for revision than for compliant patients.

Conclusion:

Large single-surface, multisurface, or bipolar shell OCA knee transplantations in athletes resulted in two-thirds of these patients returning to sport at 16 to 24 months after transplantation. Combined, the revision and failure rates were 10%; thus, 90% of patients were considered to have successful 2- to 4-year outcomes with significant improvements in pain and function, even when patients did not RTS.

Bone Allograft Prosthesis Composite to Revise a Failed Massive Allo-Prosthesis: Case Report and 10 Years of Follow-Up

An 18-year-old male patient with a high-grade osteosarcoma was initially treated with resection and reconstruction using an osteochondral allograft. The allograft collapsed after five years, and thus a revision with a constrained knee prosthesis was performed. After one year, the implant failed due to a fracture, requiring another revision with a new allo-prosthetic composite. The long-term results were satisfactory.

Allo-prosthetic composites may offer good long-term results after sarcoma resection. The failure of a massive bone allograft does not preclude the use of another allograft to maintain the bone stock and preserve the function.

Osteochondral Allograft Transplant of the Patella Using Femoral Condylar Allografts: Magnetic Resonance Imaging and Clinical Outcomes at Minimum 2-Year Follow-up

Background:

Fresh osteochondral allograft transplant (OCA) has good outcomes in the knee. However, donor tissue for patellar OCA is limited. Outcomes after nonorthotopic OCA of the patella using more readily available femoral condylar allograft (FCA) tissue have not been previously reported.

Purpose:

To assess short-term magnetic resonance imaging (MRI) and minimum 2-year clinical outcomes of nonorthotopic patellar OCA using an FCA donor.

Study Design:

Case series; Level of evidence, 4.

Methods:

A prospective institutional cartilage registry was reviewed to identify patients treated with patellar OCA using an FCA donor between August 2009 and June 2016. OCA plugs were obtained from the FCA at its trochlear-condylar junction and implanted into the recipient patellar lesion. Early postoperative MRI scans were graded by a blinded musculoskeletal radiologist using the Osteochondral Allograft MRI Scoring System (OCAMRISS). International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC), Knee Outcomes Survey–Activities of Daily Living (KOS-ADL), and pain visual analog scale (VAS) scores were collected preoperatively and at minimum 2 years postoperatively, and outcomes were compared using the paired t test.

Results:

A total of 25 patients were included for clinical outcome analysis and 20 patients for MRI analysis. MRI scans obtained at a mean of 11.4 months (range, 6-22 months) postoperatively showed a mean total OCAMRISS score of 9.0 (range, 7-11); mean bone, cartilage, and ancillary subscores were 2.6, 3.7, and 2.6, respectively. At the latest follow-up (mean, 46.5 months; range, 24-85 months), postoperative improvements were noted in IKDC (from 45.0 to 66.2; P = .0002), KOS-ADL (from 64.3 to 80.4; P = .0012), and VAS (from 5.1 to 3.4; P = .001) scores, with IKDC and KOS-ADL scores above the corresponding previously reported minimal clinically important difference.

Conclusion:

In this study, patellar OCA using nonorthotopic FCA led to significant short-term improvements in pain and patient-reported outcomes. The majority of nonorthotopic patellar grafts demonstrated full osseous incorporation and good restoration of the articular surface on MRI at short-term follow-up.

Prospective Assessment of Outcomes After Primary Unipolar, Multisurface, and Bipolar Osteochondral Allograft Transplantations in the Knee: A Comparison of 2 Preservation Methods

BACKGROUND

Articular cartilage lesions in the knee remain a challenging clinical problem.

HYPOTHESIS

A novel graft preservation method combined with surgical technique and patient management improvements would lead to consistently successful outcomes after osteochondral allograft (OCA) transplantation.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

With institutional review board approval and informed consent, patients were prospectively enrolled into a registry to follow outcomes after OCA transplantation. Patients were included when ≥1-year follow-up data were available, including complications and reoperations, patient-reported outcome measures (PROMs), compliance with rehabilitation, revisions, and failures.

RESULTS

For patients meeting inclusion criteria (N = 194), mean ± SD age was 37.9 ± 12.2 years and mean BMI was 28.9 ± 5; 38% received unipolar transplants (44% multisurface) and 62% received bipolar transplants. OCAs were preserved by standard tissue bank methods (standard preservation [SP]; 29%) or the novel method (Missouri Osteochondral Preservation System [MOPS]; 71%). Initial success rates were 79% for all cases combined, 60% for SP, and 84% for MOPS. MOPS cases were significantly (P = .028) more likely to be associated with successful outcomes when compared with SP cases. PROMs improved significantly (P < .05) for all cohorts through 3 to 4 years of follow-up. Revisions were performed in 19 cases (10%). MOPS grafts were associated with a significantly (P = .0014) lower revision rate (5%) than SP grafts (21%). Failures occurred in 26 patients (13%), with all undergoing total knee arthroplasty. Bipolar cases were significantly (P = .008) more likely to be associated with failure. MOPS grafts were associated with a significantly (P = .048) lower failure rate (11%) than were SP grafts (19%). Noncompliance with the prescribed rehabilitation protocol was significantly (P = .00008) more likely to be associated with failure.

CONCLUSION

Prospective data for 194 cases revealed that OCA transplantation for unipolar, multisurface, and bipolar cartilage restoration can be associated with consistently successful outcomes. The 5% revision rate, 11% failure rate, 82%-94% survival probability estimates, and continually improving PROMs through postoperative 3 to 4 years underscore major advances in outcomes as compared with previous reports. These encouraging results were realized with the use of a novel graft preservation method; autogenous bone marrow concentrate pretreatment of donor bone; advancements in graft cutting, implantation, and stabilization techniques; and procedure-specific rehabilitation protocols.

Articular Cartilage Repair of the Pediatric and Adolescent Knee with Regard to Minimal Clinically Important Difference: A Systematic Review

OBJECTIVE

To perform a systematic review of clinical outcomes following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral allograft transplantation (OCA), and osteochondral autograft transplantation system (OATS) to treat articular cartilage lesions in pediatric and adolescent patients. We sought to compare postoperative improvements for each cartilage repair method to minimal clinically important difference (MCID) thresholds.

DESIGN

MEDLINE, Web of Science, Scopus, and Cochrane Library databases were searched for studies reporting MCID-validated outcome scores in a minimum of 5 patients ≤19 years treated for symptomatic knee chondral lesions with minimum 1-year follow-up. One-sample t tests were used to compare mean outcome score improvements to established MCID thresholds.

RESULTS

Twelve studies reporting clinical outcomes on a total of 330 patients following cartilage repair were identified. The mean age of patients ranged from 13.7 to 16.7 years and the mean follow-up was 2.2 to 9.6 years. Six studies reported on ACI, 4 studies reported on MFX, 2 studies reported on OATS, and 1 study reported on OCA. ACI (P < 0.001, P = 0.008) and OCA (P < 0.001) showed significant improvement for International Knee Documentation Committee (IKDC) scores with regard to MCID while MFX (P = 0.66) and OATS (P = 0.11) did not. ACI (P < 0.001) and OATS (P = 0.010) both showed significant improvement above MCID thresholds for Lysholm scores. MFX (P = 0.002) showed visual analog scale (VAS) pain score improvement above MCID threshold while ACI (P = 0.037, P = 0.070) was equivocal.

CONCLUSIONS

Outcomes data on cartilage repair in the pediatric and adolescent knee are limited. This review demonstrates that all available procedures provide postoperative improvement above published MCID thresholds for at least one reported clinical pain or functional outcome score.

Effects of Compliance With Procedure-Specific Postoperative Rehabilitation Protocols on Initial Outcomes After Osteochondral and Meniscal Allograft Transplantation in the Knee

Background:

Osteochondral and meniscal allograft transplantation have been performed in the knee for more than 40 years, with the number of patients treated each year growing as allograft quantity and quality increase. To date, the effects of postoperative management on outcomes after these procedures have received relatively little focus in the peer-reviewed literature.

Hypothesis:

Compliance with the recommended postoperative management protocol will be associated with significantly higher initial success and significantly lower revision and failure rates for patients undergoing osteochondral and/or meniscal allograft transplantation in the knee.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients were prospectively enrolled into a dedicated registry designed to follow outcomes after osteochondral and/or meniscal allograft transplantation. Patients were included when at least 1 year of follow-up data were available, including data on complications and reoperations, patient-reported outcome measures, compliance with rehabilitation, revisions, or failures, based on the electronic medical record and communication logs with patients’ outpatient physical therapists.

Results:

For patients meeting the inclusion criteria (N = 162), compliance with the prescribed procedure-specific postoperative management protocol was associated with significantly higher 1- to 3-year success and significantly lower revision and failure rates. Specifically, patients who were compliant were 6.3 times less likely to need allograft revision or total knee arthroplasty and 7.5 times more likely to have a successful outcome at 1 to 3 years after osteochondral and/or meniscal allograft transplantation. In addition to noncompliance, older patient age and higher body mass index were associated with inferior short-term outcomes in this cohort.

Conclusion:

These data suggest that compliance with procedure-specific postoperative rehabilitation protocols is associated with higher success, lower revision, and lower failure rates for patients undergoing osteochondral and meniscal allograft transplantation. Given these results showing the importance of these modifiable risk factors, our center has devoted resources to preoperative patient assessment and communication to provide education, set appropriate expectations, identify and address modifiable risk factors, impediments, and noncompliance, and monitor and adjust postoperative care as indicated.