Osteoarticular autograft and allograft transplantation of the knee: 3 year follow-up

Patient-Specific Distal Femoral Guides Optimize Cartilage Topography Matching in Osteochondral Allograft Transplantations

BACKGROUND

Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching.

PURPOSE

To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured.

RESULTS

The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm.

CONCLUSION

These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching.

CLINICAL RELEVANCE

Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources.

3D Printed Multiphasic Scaffolds for Osteochondral Repair: Challenges and Opportunities

Osteochondral (OC) defects are debilitating joint injuries characterized by the loss of full thickness articular cartilage along with the underlying calcified cartilage through to the subchondral bone. While current surgical treatments can provide some relief from pain, none can fully repair all the components of the OC unit and restore its native function. Engineering OC tissue is challenging due to the presence of the three distinct tissue regions. Recent advances in additive manufacturing provide unprecedented control over the internal microstructure of bioscaffolds, the patterning of growth factors and the encapsulation of potentially regenerative cells. These developments are ushering in a new paradigm of 'multiphasic' scaffold designs in which the optimal micro-environment for each tissue region is individually crafted. Although the adoption of these techniques provides new opportunities in OC research, it also introduces challenges, such as creating tissue interfaces, integrating multiple fabrication techniques and co-culturing different cells within the same construct. This review captures the considerations and capabilities in developing 3D printed OC scaffolds, including materials, fabrication techniques, mechanical function, biological components and design.

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

BACKGROUND

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

PURPOSE

To perform a systematic review of clinical outcomes and failure rates after OCA transplantation in the knee at a minimum mean 2 years' follow-up.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

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

RESULTS

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

CONCLUSION

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

Review of Mechanical, Processing, and Immunologic Factors Associated With Outcomes of Fresh Osteochondral Allograft Transplantation of the Talus

Osteochondral lesions of the talus (OLTs) are an increasingly implicated cause of ankle pain and instability. Several treatment methods exist with varying clinical outcomes. Due in part to successful osteochondral allografting (OCA) in other joints, such as the knee and shoulder, OCA has gained popularity as a treatment option, especially in the setting of large lesions. The clinical outcomes of talar OCA have been inconsistent relative to the positive results observed in other joints. Current literature regarding OCA failure focuses mainly on 3 factors: the effect of graft storage conditions on chondrocyte viability, graft/lesion size, and operative technique. Several preclinical studies have demonstrated the ability for bone and cartilage tissue to invoke an immune response, and a limited number of clinical studies have suggested that this response may have the potential to influence outcomes after transplantation. Further research is warranted to investigate the role of immunological mechanisms as an etiology of OCA failure.

LEVEL OF EVIDENCE

Level V, expert opinion.

Osteochondral Allograft Transplantation in Patients With Osteochondritis Dissecans of the Knee

BACKGROUND

Osteochondritis dissecans (OCD) of the knee can be difficult to treat. Cartilage restoration techniques are often indicated when the lesion or fragment cannot be salvaged and the patient remains symptomatic. Fresh osteochondral allograft (OCA) transplantation can restore both bone and cartilage defects characteristic of OCD.

HYPOTHESIS

We hypothesized that osteochondral allografting is a successful method for treating OCD of the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This study comprised 135 patients (149 knees) who underwent OCA for OCD of the knee (type III or IV) between 1997 and 2013 and had a minimum follow-up of 2 years. The median age was 21 years (range, 12-55 years) and 75.8% of the patients were male. The mean allograft size was 7.3 cm² (range, 2.2-25 cm²). Evaluation included the following: frequency and type of reoperations; modified Merle d'Aubigné and Postel (18-point) scale; International Knee Documentation Committee (IKDC) pain, function, and total scores; and Knee Society function (KS-F) and knee (KS-K) scores. Clinical failure was defined as revision OCA or conversion to arthroplasty. Graft survivorship was determined.

RESULTS

The median follow-up time was 6.3 years (range, 1.9-16.8 years) and 62% of participants had more than 5-year follow-up. Thirty-four of 149 knees (23%) had reoperations, of which 12 (8%) were classified as allograft failures (7 OCA revisions, 3 unicompartmental knee arthroplasties, and 2 total knee arthroplasties). OCA survivorship was 95% at 5 years and 93% at 10 years. Of the 137 knees whose grafts were still in situ at the latest follow-up, the mean modified Merle d'Aubigné and Postel (18-point) score was 16.8; IKDC pain, function, and total scores were 2.1, 8.1, and 82.3; and KS-F and KS-K scores were 95.7 and 94.3, respectively. The majority of patients (95%) reported being satisfied with the outcome of their procedure.

CONCLUSION

OCA transplantation was an effective treatment for OCD of the knee, with a low rate of graft failure, significant improvement in pain and function scores, and high patient satisfaction.

Long-term Outcomes After Osteochondral Allograft: A Systematic Review at Long-term Follow-up of 12.3 Years

PURPOSE

To (1) evaluate long-term outcomes of osteochondral allograft (OCA) with regard to clinical outcome scores, reoperation and failure rates, and (2) examine if certain factors predispose patients to worse outcomes.

METHODS

A comprehensive review was performed with specific inclusion criteria for studies with long-term outcomes after OCA. Studies reported on patient clinical scores such as Hospital for Special Surgery score, Knee Society Score (knee and function score), and Lysholm score. Reoperation and failure rates were recorded for each study. Modified Coleman Methodology Scores assessed study methodological quality.

RESULTS

Five studies with a total of 291 patients (55% male, 45% female) and average age of 34.8 years (range, 15 to 69 years) were included. Of all lesions, 67% were on the femoral condyles, 29% on the tibial plateau, and 4% were patellofemoral. All scores (Knee Society Function Score, Knee Society Knee Score, and Lysholm score) have significant mean improvement from preoperative to final follow-up. The mean postoperative Hospital for Special Surgery score was 84.1. The mean failure rate was 25% at 12.3 years with a reoperation rate of 36%. A total of 72% of the failures were conversion to total (68%) or unicompartmental (4%) knee arthroplasty and 28% involved graft removal, graft fixation, and graft revision. Patellofemoral lesions (83%) had a significantly higher reoperation rate than lesions involving the tibial plateau or the femoral condyles (34%, P = .01).

CONCLUSIONS

Overall, OCA demonstrated significant improvements in clinical outcome scores and good durability with successful outcomes in 75% of the patients at 12.3 years after surgery. Patellofemoral lesions are associated with decreased clinical improvement and more frequent reoperations. The orthopaedic literature is limited by heterogeneity in surgical technique, lesion and patient characteristics, and reporting of nonstandardized outcome measures.

LEVEL OF EVIDENCE

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

Surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults

BACKGROUND

Cartilage defects of the knee are often debilitating and predispose to osteoarthritis. Microfracture, drilling, mosaicplasty, and allograft transplantation are four surgical treatment options that are increasingly performed worldwide. We set out to examine the relative effects of these different methods.

OBJECTIVES

To assess the relative effects (benefits and harms) of different surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL, EMBASE, MEDLINE, SPORTDiscus, LILACS, trial registers and conference proceedings up to February 2016.

SELECTION CRITERIA

Any randomised or quasi-randomised trials that evaluated surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected studies, assessed risk of bias and extracted data. Intervention effects were assessed using risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data, with 95% confidence intervals (CI). Data were pooled using the fixed-effect model, where possible.

MAIN RESULTS

We included three randomised controlled trials comparing mosaicplasty versus microfracture for isolated cartilage defects in adults. Two trials were single-centre trials and one involved three centres. These small trials reported results for a total of 133 participants, of whom 79 (59%) were male. Mean participant age in the three trials ranged from 24.4 years to 32.3 years. All studies included grade 3 or 4 cartilage lesions (International Cartilage Repair Society (ICRS) classification). The defect area ranged from 1.0 cm² to 6.0 cm²; the mean area in all three trials was 2.8 cm². No trials of allograft transplantation or drilling were identified.All trials were judged as being at high or unclear risk of performance and reporting bias. We judged that the quality of evidence was very low for all outcomes. For individual outcomes, we downgraded the quality of evidence by one or two levels for risk of bias, one level for indirectness where there were data from a single-centre trial only, one or two levels for imprecision where there were wide confidence intervals and an insufficient number of events, and one level for inconsistency reflecting heterogeneity. This means that we are very uncertain about the estimates for all outcomes.There is very low quality evidence from one single-centre trial (57 participants), which included athletes only, that mosaicplasty resulted in higher patient-reported function scores (probably the IKDC 2000 subjective knee evaluation score) compared with microfracture (range 0 to 100; higher score = better function) at one year follow-up (MD 10.29 favouring mosaicplasty, 95% CI 7.87 to 12.71). Very low quality evidence from the same trial showed that this effect persisted in the long term at 10 years follow-up. However, there is very low quality evidence from the two other trials (72 participants) of little difference in patient-reported function, assessed via the Lysholm score (range 0 to 100; higher score = better function), between the two groups at long-term follow-up (MD -1.10 favouring microfracture, 95% CI -4.54 to 2.33). One trial (25 participants) provided very low quality evidence of no significant difference between the two groups in quality of life or pain at long-term follow-up. Pooled results for treatment failure - primarily symptom recurrence - reported at long-term follow-up (means ranging from 6.3 to 1.4 years) in the three trials (129 participants) favoured mosaicplasty (10/64 versus 20/65; RR 0.47, 95% CI 0.24 to 0.90). Based on an illustrative risk of 379 treatment failures per 1000 patients treated with microfracture, there is very low quality evidence that 201 fewer patients (95% CI 38 to 288 fewer) would have treatment failure after mosaicplasty. All three trials reported activity scores but due to clear statistical and clinical heterogeneity, we did not pool the long term Tegner score results. There was very low quality evidence from one study (57 participants) of higher Tegner scores - indicating greater activity - at intermediate-term and long-term follow-up in the mosaicplasty group; however, the between-group difference may not be clinically important. The other two trials provided very low quality evidence of no significant difference between the two groups in activity scores.

AUTHORS' CONCLUSIONS

We found no evidence from randomised controlled trials on allograft transplantation or drilling. The very low quality evidence from RCTs comparing mosaicplasty with microfracture is insufficient to draw conclusions on the relative effects of these two interventions for treating isolated cartilage defects of the knee in adults. Of note is that treatment failure, with recurrence of symptoms, occurred with both procedures. Further research is needed to define the best surgical option for treating isolated cartilage defects. We suggest the greatest need is for multi-centre RCTs comparing reconstructive procedures (mosaicplasty versus allograft transplantation) for large osteochondral lesions and reparative procedures (microfracture versus drilling) for small chondral lesions.

Knee salvage procedures: The indications, techniques and outcomes of large osteochondral allografts

The overall incidence of osteochondral defect in the general population is estimated to be 15 to 30 per 100000 people. These lesions can become symptomatic causing pain, swelling and decreased function of the knee, and may eventually progress to osteoarthritis. In the young and active population, partial or total knee arthroplasty (TKA) is rarely the treatment of choice due to risk of early failure. Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients. The treatment reduces pain, improves function and is a viable limb salvage procedure for patients, especially young and active patients for whom TKA is not recommended. Either large dowels generated with commercially available equipment or free hand shell allografts can be implanted in more posterior lesions. Current recommendations for fresh allografts stored at 4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability, following screening and testing protocols. Higher rates of successful allograft transplantation are observed in younger patients, unipolar lesions, normal or corrected malalignment, and defects that are treated within 12 mo of symptom onset. Patients with bipolar lesions, uncorrectable malalignment, advanced osteoarthritis, and those over 40 tend to have less favourable outcomes.

Outcomes of osteochondral allograft transplantation in the knee

PURPOSE

The objectives of this study were (1) to conduct a systematic review of clinical outcomes after osteochondral allograft transplantation in the knee and (2) to identify patient-, defect-, and graft-specific prognostic factors.

METHODS

We searched PubMed, Medline, EMBASE, and the Cochrane Central Register of Controlled Trials. Studies that evaluated clinical outcomes in adult patients after osteochondral allograft transplantation for chondral defects in the knee were included. Pooled analyses for pertinent continuous and dichotomous variables were performed where appropriate.

RESULTS

There were 19 eligible studies resulting in a total of 644 knees with a mean follow-up of 58 months (range, 19 to 120 months). The overall follow-up rate was 93% (595 of 644). The mean age was 37 years (range, 20 to 62 years), and 303 patients (63%) were men. The methods of procurement and storage time included fresh (61%), prolonged fresh (24%), and fresh frozen (15%). With regard to etiology, the most common indications for transplantation included post-traumatic (38%), osteochondritis dissecans (30%), osteonecrosis from all causes (12%), and idiopathic (11%). Forty-six percent of patients had concomitant procedures, and the mean defect size across studies was 6.3 cm(2). The overall satisfaction rate was 86%. Sixty-five percent of patients (72 of 110) showed little to no arthritis at final follow-up. The reported short-term complication rate was 2.4%, and the overall failure rate was 18%. Heterogeneity in functional outcome measures precluded a meta-analysis; a qualitative synthesis allowed for the identification of several positive and negative prognostic factors.

CONCLUSIONS

Osteochondral allograft transplantation for focal and diffuse (single-compartment) chondral defects results in predictably favorable outcomes and high satisfaction rates at intermediate follow-up. Patients with osteochondritis dissecans and traumatic and idiopathic etiologies have more favorable outcomes, as do younger patients with unipolar lesions and short symptom duration. Future studies should include comparative control groups and use established outcome instruments that will allow for pooling of data across studies.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.