Influence of basal support and early loading on bone cartilage healing in press-fitted osteochondral autografts

Autologous osteochondral transplantation for osteochondral lesions of the talus: high rate of return to play in the athletic population

PURPOSE

(1) To determine the rate of return to play following autologous osteochondral transplantation (AOT) for osteochondral lesions of the talus (OLT) and (2) report subsequent rehabilitation protocols.

METHODS

A systematic review of the PubMed, Embase, and The Cochrane Library databases was performed according to the PRISMA guidelines based on specific eligibility criteria. Return to play data was meta-analysed and subsequent rehabilitation protocols were summarised. Level of evidence and quality of evidence (Zaman's criteria) were also evaluated.

RESULTS

Nine studies that totalled 205 ankles were included for review. The mean follow-up was 44.4 ± 25.0 (range 16-84) months. The mean OLT size was 135.4 ± 56.4 mm². The mean time to return to play was 5.8 ± 2.6 months. The mean rate of return to play was 86.3% (range 50-95.2%), with 81.8% of athletes returning to pre-injury status. Based on the fixed-effect model, the rate of return to play was 84.07%. Significant correlation was found between increase age and decrease rate of return to play (R² = 0.362, p = 0.00056). There was no correlation between OLT sizes and rate of return to play (R² = 0.140, p = 0.023). The most common time to ankle motion post-surgery was immediately and the most common time to full weight-bearing was 12 weeks.

CONCLUSIONS

This systematic review indicated a high rate of return to play following AOT in the athletic population. Size of OLT was not found to be a predictor of return to play, whereas advancing age was a predictor. Rehabilitation protocols were largely inconsistent and were primarily based on individual surgeon protocols. However, the included studies were of low level and quality of evidence.

LEVEL OF EVIDENCE

Level IV.

An experimental simulation model to assess wear of the porcine patellofemoral joint

A range of surgical techniques and osteochondral interventions have been developed for early stage chondral/osteochondral repair interventions in the knee however, methods for functional, pre-clinical assessment of these therapies are limited. In this study, a method for simulating physiological loading and motion in the porcine patellofemoral joint was developed using a 6-axis simulator. As an example of how the method can be used, the influence of surgical positioning of osteochondral allografts in the patella on cartilage wear, deformation and damage and graft stability was investigated in this porcine patellofemoral joint model. The functional performance of allografts implanted either optimally (flush with the cartilage surface) or 1 mm proud of the cartilage surface was compared to a positive control (stainless steel pin implanted 1 mm proud of the cartilage surface), a negative control (no intervention) and a defect model. Allografts implanted flush with the surrounding cartilage could restore the articulating surface of the patella resulting in low wear, damage and deformation of the opposing cartilage surface, similar to that of the negative control group. Implanting the graft proud of the patella surface resulted in cartilage lesions on the femoral trochlea (ICRS grade 2) and a cartilage volume difference of 2.0 ± 3.9 mm3; the positive controls resulted in more severe lesions, a higher volume difference (14.2 ± 7.4 mm3) which in some cases exposed subchondral bone (ICRS grade 4). Defects in the patella caused deformation of the opposing cartilage surface. All grafts implanted in the patella subsided over the duration of the study. This study demonstrated a method that can be used to evaluate osteochondral repair strategies in the patellofemoral joint applying physiological loading and motions.

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

Background

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

Purpose

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

Study Design

Consensus statement.

Methods

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

Results

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

Conclusion

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

Treatment of osteochondral defects: chondrointegration of metal implants improves after hydroxyapatite coating

PURPOSE

The treatment of osteochondral defects in joint cartilage remains challenging due to its limited repair capacity. This study presents a metallic osteochondral plug with hydroxyapatite (HA)-coated cap edges for improved implant-tissue contact. The hypothesis was that improved attachment prevents from synovial fluid-influx and thereby avoids osteolysis and resulting implant instability.

METHODS

In total, 24 female, adult sheep were randomized into three groups. All animals received an Episealer^®-implant in the medial condyle of the right knee. The implants were coated with two different HA versions or uncoated (control group). After 12 weeks, the implant-tissue connections were analysed radiologically and histologically.

RESULTS

In general, the groups with the coated cap edges showed a better quality of tissue connection to the implant. The occurrence of gaps between tissue and implant was more seldom, the binding of calcified and hyaline cartilage to the cap was significantly better than in the uncoated group. A histomorphometrically measured lower amount of void space in these groups compared to the group with the uncoated edges confirmed that.

CONCLUSIONS

The hypothesis of a tighter cartilage bone contact was confirmed. The HA coating of the implant's cap edges resulted in better adherence of cartilage to the implant, which was not previously reported. In conclusion, this led to a better contact between implant and cartilage as well as neighbouring bone. In clinical routine, joint fluid is aggressive, penetrates through cartilage rifts, and promotes osteolysis and loosening of implants. The observed sealing effect will act to prevent joint fluid to get access to the implant-tissue interfaces. Joint fluid is aggressive, can cause osteolysis, and can, clinically cause pain. These effects are liable to decrease with these findings and will further the longevity of these osteochondral implants.

Current Trends in the Evaluation of Osteochondral Lesion Treatments: Histology, Histomorphometry, and Biomechanics in Preclinical Models

Osteochondral lesions (OCs) are typically of traumatic origins but are also caused by degenerative conditions, in primis osteoarthritis (OA). On the other side, OC lesions themselves, getting worse over time, can lead to OA, indicating that chondral and OC defects represent a risk factor for the onset of the pathology. Many animal models have been set up for years for the study of OC regeneration, being successfully employed to test different treatment strategies, from biomaterials and cells to physical and biological adjuvant therapies. These studies rely on a plethora of post-explant investigations ranging from histological and histomorphometric analyses to biomechanical ones. The present review aims to analyze the methods employed for the evaluation of OC treatments in each animal model by screening literature data within the last 10 years. According to the selected research criteria performed in two databases, 60 works were included. Data revealed that lapine (50% of studies) and ovine (23% of studies) models are predominant, and knee joints are the most used anatomical locations for creating OC defects. Analyses are mostly conducted on paraffin-embedded samples in order to perform histological/histomorphometric analyses by applying semiquantitative scoring systems and on fresh samples in order to perform biomechanical investigations by indentation tests on articular cartilage. Instead, a great heterogeneity is pointed out in terms of OC defect dimensions and animal's age. The choice of experimental times is generally adequate for the animal models adopted, although few studies adopt very long experimental times. Improvements in data reporting and in standardization of protocols would be desirable for a better comparison of results and for ethical reasons related to appropriate and successful animal experimentation.

Review of the biomechanics and biotribology of osteochondral grafts used for surgical interventions in the knee

A review of research undertaken to evaluate the biomechanical stability and biotribological behaviour of osteochondral grafts in the knee joint and a brief discussion of areas requiring further improvement in future studies are presented. The review takes into consideration osteochondral autografts, allografts, tissue engineered constructs and synthetic and biological scaffolds.

Autologous osteochondral transplantation for osteochondral lesions of the talus in an athletic population

PURPOSE

To assess clinical outcomes and return to sport in an athletic population treated with autologous osteochondral transplantation (AOT) for osteochondral lesions of the talus.

METHODS

A total of 36 patients were included in this retrospective study including 21 professional athletes and 15 amateur athletes who participated in regular moderate- or high-impact athletic activity. All patients underwent autologous osteochondral transplantation of the talus under the care of a single surgeon. At a mean follow-up of 5.9 years, patients were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system. All patients also received pre-operative MRI with the follow-up MRI performed at 1 year and underwent assessment of return to athletic activity.

RESULTS

The overall AOFAS score improved from 65.5 (SD ± 11.1) to 89.4 (SD ± 14.4) (p = 0.01). At a final follow-up, 90% of professional athletes (19 of 21) were still competing in athletic activity or still able to participate in unrestricted activity. Of the recreational athletes, 87% (13 of 15) had full return to pre-injury activity levels, while two (13%) returned to activity with restrictions or reduced intensity. MRI showed cystic change in 33% of patients post-operatively; however, this did not appear to affect outcomes (n.s.). Donor site symptoms were seen in 11% of the cohort at final follow-up, despite high function at donor knee.

CONCLUSION

The results of our study indicate that AOT procedure is able to achieve good outcomes in an athletic population at a midterm follow-up.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.