Abstract
Talar dome osteo-chondral lesions (OCL) are defects of the cartilaginous surface and subchondral bone often associated with sport practice. This retrospective observational work has the purpose of assessing: a) The clinical outcomes in the patients study group and in the three sub-groups; b) medium-term morphological and qualitative outcomes of the newly formed tissue by magnetic resonance imaging; c) if there is the correlation between new formed tissue clinical, morphological RM evaluation and qualitative clinical outcomes.
Keywords: Osteochondral lesions, Drilling, Autologous chondrocytes implantation, Allograft
1. Introduction
Talar dome osteo-chondral lesions (OCL) are defects of the cartilaginous surface and subchondral bone often associated with sport practice. In recent years, therapeutic approaches and surgical techniques in this area have seen a rapid development and a continuous improvement. The goal of our study was to evaluate clinical and morphological outcomes of talar dome chronic OCL treated with three methods: (see Fig. 1, Fig. 2)
-
i)
Micro-perforations;
-
ii)
Mesenchymal cells grafts, harvested from ipsilateral iliac crest and injection on a specific device (IOR-G1, Novagenit, Mezzolombardo, Italy),
-
iii)
Fresh osteochondral allograft.
Fig. 1.
Magnetic resonance image of a patient treated with the Allograft treatment. Left: Pre-operative image; Middle: 12 Months post intervention; Right: 24 Months post intervention.
Fig. 2.
Magnetic resonance image of a patient treated with the Mesenchymal cells graft treatment. Left: Pre-operative image; Right: 24 Months post intervention.
In addition, this retrospective observational study has the purpose of assessing the medium-term morphological and qualitative outcomes of the newly formed tissue by magnetic resonance imaging and whether a correlation between new formed tissue clinical, morphological and qualitative outcomes was present.
2. Methods
2.1. Patients and setting
The study included patients with chronic focal Osteo-Chondral lesions (OCL) of the astragalus, treated arthroscopically or by arthrotomy, employing the aforementioned surgical methods. All surgeries were performed by the same first operator assisted by the same team between July 2014 and March 2017 at the hospital of Rovereto, Trento, Italy. Talar dome chronic (OCL) were treated according to the following algorithm1:
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1.
Asymtomatic patients with occasional OCL deteetion: “wait and see” conservative treatment;
-
2.
Not open cystic lesion: conservative treatment, wad or retro-drilling;
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3.
Symptomatic communicating osteochondral lesion with articular surface damage, surface <1.5 cm2 and depth <0.8 mm: cleaning and microfractures;
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4.
Symtomatic communicating osteochondral lesion with articular surface damage, surface >1.5 cm2 and depth <0.8 mm: bone marrow mononuclear cell transplantation (BMMNCT);
-
5.
Symtopatic communicating osteochondral lesion with articular surface damage, surface >1.5 cm2 and depth >0.8 mm involving the super-medial and super-lateral talar “shoulders”, with loss of normal morphology and joint congruence: osteochondral transplant with allograft.
2.2. The exclusion criteria were
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a)
Clinical or objective conditions of the subject not compatible with MRI;
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b)
Surgical interventions or traumas that may have modified the injury site;
-
c)
Infections in the affected joint
2.3. Study protocol
The surgical treatment was selected based on Giannini's classification.1 In the pre-operative phase, each patient underwent an anamnestic evaluation with particular attention to any trauma, previous treatments of the ankle under examination, presence or not of instability, alignment, ROM. For every patient the AOFAS (American Orthopedic Foot and Ankle Society) clinical score was filled.2 The clinical/functional variation between the pre-operative and post-intervention status was calculated using the formula:
| (AOFAS score at follow-up – AOFAS score pre-op) / (100 - AOFAS scpre pre-op) * 100 |
In the pre-operative phase, bilateral anterior-posterior and lateral x-rays standing were performed for each patient as well as magnetic resonance imaging,3 through which the area and depth of the lesion was measured. The patients were clinically re-evaluated 1 and 6 months after surgery. New MRI were made 12 and 24 months after surgery. We choose 24 months as the minimum follow-up because it represents the minimum maturation time for the newly formed cartilage tissue.4
The quality of the newly formed cartilage tissue was assessed using Magnetic Resonance Imaging (MRI). NMR allows to obtain cartilage morphological and qualitative information through the use of specific sequences (e.g. T2, T1ρ, dGEMRIC, “sodium MRI”, etc.); in particular the T2-mapping5 of the tissue distinguishes the cartilage tissue from the repair one.6,7 T2 values were considered equivalent to those of hyaline cartilage8,9 for values between 35 and 45 ms.
2.4. Statistical analyses
The descriptive variables of the populations under examination were expressed by mean ± standard deviation in case of continuous variables with normal distribution, or by means of median and value at the 25th and 75th percentiles in case of variables with non-normal distribution. The dichotomous variables or scores, were expressed as frequencies and occurrence percentages. The normality of the variables will be tested with the Shapiro-Wilk test.
The outcomes were analyzed in a descriptive fashion, indeed we reported the AOFAS average values for each of the 3 patients’ groups. The percentage of patients who reached an optimal MOCART (magnetic resonance observation of cartilage repair tissue) value at a minimum follow-up of 2 years was calculated.
Statistical analyzes were performed using the Stata software, StataCorp, 4905 Lakeway Drive, College Station, Texas 77,845 USA.
3. Results
We globally analyzed data related on 28 patients. Patients, according to the received treatment, were divided into 3 groups: 9 patients were treated with micro-perforations,10 11 with bone marrow mononuclear cell transplantation (BMMNCT)11, 12, 13 and 8 with osteochondral allograft transplantation.14,15
The patients treated with micro-fractures had a chronic type C1 lesion according to Giannini's classification. The lesion had an average area of 0.67 cm2 (0.23–1.67), with a depth of 6 mm (5–8) and on average had place 14 months before treatment (minimum 3, maximum 32). This group consisted of 9 patients, 5 males and 4 females, with an average age of 35 years (minimum 18, maximum 56) and average BMI 23; they were operated in the period between November 2014 and February 2017. The average follow-up was 46 months (minimum 31, maximum 57).
The traumatic etiology of the lesion was recognized in 7 patients (4 associated with ankle dislocation and 3 with malleolar fracture). The lesion affected the right ankle in 5 patients and the left ankle in the remaining 4, localizing in the lateral part of the talar articular surface in 6 cases and in the medial part in 3. None of the patients belonging to this group reported any previous surgical treatment. 7 patients underwent accessory surgical gestures during the operation (ligament reconstruction and impingement elimination) (Table 1).
Table 1.
Baseline characteristics’ of patients divided by group, and pre and post-operative AOFAS.
| Micro-perforations (tot. 9 patients) | Mesenchymal cells draft (tot. 11 patients) | Osteo-chondral allograft graft (tot. 8 patients) | ||
|---|---|---|---|---|
| Gender n (%) | M | 5 (55) | 8 (73) | 8 (100) |
| F | 4 (45) | 3 (27) | 0 (0) | |
| BMI, average (Standard Deviation) | 23 (3) | 26 (3) | 28 (5) | |
| Age at Surgery, Average (Standard Deviation) | 35 (15) | 36 (14) | 42 (16) | |
| Age at F–U, Average (Standard Deviation) | 39 (15) | 40 (14) | 47 (16) | |
| Months of F–U, Average (Standard Deviation) | 46 (10) | 47 (10) | 51 (8) | |
| Months between lesion and Surgery, Average (Standard Deviation) | 14 (9) | 32 (21) | 23 (29) | |
| Lesion n (%) | Medial | 3 (34) | 6 (55) | 6 (75) |
| Lateral | 6 (66) | 5 (45) | 2 (25) | |
| Side n (%) | Left | 4 (45) | 5 (45) | 4 (50) |
| Right | 5 (55) | 6 (55) | 4 (50) | |
| Trauma n (%) | Yes | 7 (77) | 7 (63) | 6 (75) |
| No | 2 (23) | 4 (36) | 2 (25) | |
| Previous surgeries n (%) | Yes | 0 (0) | 5 (45) | 4 (50) |
| No | 9 (100) | 6 (55) | 4 (50) | |
| Associated Surgery n (%) | Si | 7 (77) | 5 (45) | 2 (25) |
| No | 2 (23) | 6 (55) | 6 (75) | |
| Lesion Area (cm2), Average (Standard Deviation) |
0,67 (1) | 1,4 (0,23) | 1,93 (1) | |
| Lesion Depth (mm), Average (Standard Deviation) |
6 (1) | 6 (1,76) | 11 (3) | |
| AOFAS pre-op, Average (Standard Deviation) | 65 (8) | 62 (12) | 57 (10) | |
| AOFAS follow up, Average (Standard Deviation) | 97 (7) | 94 (8) | 87 (11) | |
Patients treated with mesenchymal cell transplant had a chronic type C2 lesion. The lesion had an average area of 1.04 cm2 (0.67–1.40), with a depth of 6 mm (4–10) and had place on average 32 months before treatment (minimum 12, maximum 87). This group was composed by 11 patients, 8 males and 3 females, with an average age of 36 years (minimum 17, maximum 60) and average BMI 26. Average follow-up was 47 months (minimum 29, maximum 60). The traumatic etiology of the lesion was recognized in 7 patients (3 associated with ankle fracture, 4 associated with ankle sprain). The lesion affected the right ankle in 6 patients and the left ankle in 5, localizing in the medial part of the talar articular surface in 6 cases and in the lateral part in the remaining 5.5 patients reported to have had previous interventions for the treatment of this lesion: micro-perforations in 3 cases, joint cleaning and cartilaginous shaving in one case, and a bone allograft in one case. 5 patients required accessory surgical interventions at the time of treatment: a distal tibial valgus osteotomy stabilized with a plate, osteophyte removal because of impingement in 3 cases and repair of the anterior astragal peroneal ligament in 1 case (Table 1).
Patients treated with allograft had a chronic C2a type lesion. The lesion had an average area of 1.93 cm2 (1.33–3), with a depth of 11 mm (6–13) and on average had place 23 months before treatment (minimum 1, maximum 64). This group was composed of 8 male patients, with an average age of 42 years (minimum 22, maximum 59) and average BMI 28. Average follow-up was 51 months (minimum 43, maximum 60). The traumatic etiology of the lesion (ankle sprain) was recognized in 6 patients. The lesion affected the right ankle in 4 patients and the left ankle in the remaining 4, localizing in the medial part of the joint surface in 6 cases and in the lateral part in the remaining 2.4 patients reported to have undergone previous surgeries for the treatment of this osteochondral lesion: fixation of the osteo-chondral fragment with screws performed elsewhere in 2 cases and lateral ligament reconstruction in other 2 cases. (Table 1).
In the case study examined, there were no intra-operative complications or failures. At the average 47-month follow-up (SD 10), the AOFAS clinical score went from a pre-operative value of 61 (SD 10) to a follow-up value of 94 (SD 8). Patients treated with micro perforations had an average AOSAF score increase of 90% (SD 7.4), going from an average pre-operative AOFAS of 65 (SD 8) to 97 (SD 7) at follow-up. Similar increase occurred in patients treated with mesenchymal cell graft, having gone from a pre-operative AOFAS-score of 62 (SD 12) to 94 (SD 8) with a percentage increase of 83% (SD 10). In patients treated with allograft there was a 71% clinical improvement (SD 10), going from a pre-operative score of 57 (SD 10) to 88 (SD 11). The average pre-operative AOSAF score is lower in patients treated with osteochondral allograft graft (average value 57) compared to those treated with mesenchymal cell graft (average value 62) compared to those treated with micro-fractures (average value 65); this reflects the width and depth of the lesion (Table 2). The morphological evaluation of the repaired cartilage was carried out using the MOCART score, obtaining the following average values for the three groups: micro-fractures 75, allograft graft 55 and mesenchymal cell graft 59. The osteochondral defect was completely filled in 25% of the patients with allograft graft and in 36% of the patients with mesenchymal cell graft, while no patient who underwent micro-perforations achieved a complete filling of the defect. 75% of patients with allograft graft achieved incomplete defect filling <50%. 36% of patients treated with mesenchymal cell graft had more than half of the osteochondral defect filled and the remaining 27% were even hypertrophic.
Table 2.
Morphological qualitative evaluation of the new tissue by MRI and Mocart Score for the three groups of patients.
| Parameter and Degree | Micro-Perforation (9 patients) % | Mesenchymal cells draft % (tot. 11 patients) | Osteo-chondral allograft graft % (tot. 8 patients) | |
|---|---|---|---|---|
| Degree of the osteochondral defect Filling | complete | 0 | 36 | 25 |
| hypertrophic | 22 | 27 | 0 | |
| Incomplete Above 50% |
44 | 36 | 0 | |
| incomplete below 50% |
22 | 0 | 75 | |
| Subchondral bone exposure |
11 |
0 |
0 |
|
| Graft margins integration | complete | 78 | 55 | 0 |
| incomplete with demarcated margins | 22 | 27 | 75 | |
| Incomplete <50% | 0 | 18 | 25 | |
| Incomplete >50% |
0 |
0 |
0 |
|
| Graft surface | intact | 22 | 9 | 25 |
| Damaged <50% with respect to the surrounding cartilage | 78 | 82 | 25 | |
| Damaged >50% with respect to the surrounding cartilage |
0 |
9 |
50 |
|
| Graft Structrure | Homogeneous | 78 | 27 | 25 |
| Not Homogeneous |
22 |
73 |
75 |
|
| Graft signal strength in DPFSE | Isointense | 100 | 45 | 75 |
| Mildly iperintense | 0 | 55 | 25 | |
| Markedly iperintense |
0 |
0 |
0 |
|
| Subchondral lamina Integrity | Intact | 44 | 36 | 0 |
| Not intact |
56 |
64 |
100 |
|
| Subchondral bone integrity | Intact | 22 | 0 | 0 |
| Not Intact |
78 |
100 |
100 |
|
| Presence of adhesions | Yes | 0 | 0 | 0 |
| No |
100 |
100 |
100 |
|
| Presence of joint effusion | Yes | 22 | 45 | 0 |
| No |
78 |
55 |
100 |
|
| T2 fse signal strength | Isointense | 100 | 18 | 50 |
| Marketly Iperintense |
0 | 82 | 50 | |
| Mildly Iperintense |
0 | 0 | 0 | |
In the group of patients who underwent micro perforations, a defect filling failed to develop in 11% of cases with subchondral bone exposure, in 22% of cases filling was less than 50%, in 44% filling was greater than 50%, while in 22% of cases a hypertrophic filling of the defect was achieved. The edges of the defect were fully integrated in 78% of patients treated with micro-perforations and in 55% of patients treated with mesenchymal cell grafting; in the allograft-treated group, 75% of patients had incomplete graft margins integration.
The signal strength from the repair tissue was isointense in all patients who underwent micro-fractures and in 75% of those who underwent allograft grafting, while over half of patients with mesenchymal cell graft had a moderately hyper-intense graft signal. The subchondral lamina is intact in 44% of patients with micro-fractures, in 36% of those with mesenchymal cell graft and in no patient who had undergone allograft grafting. All patients treated with allograft or mesenchymal cell grafts had non-intact subchondral bone, which also occurred in 78% of those treated with micro-fractures (Table 2).
4. Discussion
The study showed an improvement in the AOFAS clinical score, which went from an average pre-operative value of 61 (SD 10) to a follow-up value of 94 (SD 8), classified as excellent with an average increase of 81% (SD 9).
This improvement in the three groups was greater in patients treated with micro-perforations (average increase of 90%) and in patients treated with mesenchymal cells (average increase of 83%) compared to the sub-group treated by allograft in which the average increase in the AOFAS index was 71%, which could suggest how the allograft replacement intervention in massive lesions could be considered a “rescue” intervention.
As regards the morphological qualitative evaluation of the new tissue formation, assessed by MRI and Mocart Score, the following average scores were obtained in the three groups: micro-fractures 75, allograft graft 55 and mesenchymal cell graft 59. The subsequent statistical analysis highlighted a statistically significant difference between the 2 most numerous groups.
The scores results of the individual parameters that the Mocart score allows to evaluate, showed heterogeneity within the three groups. In particular, the degree of the osteochondral defect filling was complete, hypertrophic or incomplete, but greater than 50%, in over two thirds of the patients belonging to the groups treated with microfractures or mesenchymal cells; on the contrary this occurred only in 2 out of 8 patients of the allograft-treated group. Those two patients, however showed a complete defect filling and at the subsequent analysis by T2 Mapping sequence showed signs of neo-cartilage hyaline in over 80% of the treated area.
The graft surface was intact or damaged for less than 50% of the treated surface in over 90% of the micro-fractures or mesenchymal cells patients groups, while this occurred only in two of the 8 patients treated with allografts.
5. Conclusion
The clinical results with a short to medium term follow-up allow us to state that the surgical techniques adopted can offer satisfactory results in the treatment of talus OCL.
The appropriateness in indicating the three surgical techniques examined remains a fundamental factor in order to obtain good clinical outcomes.
The assessments made using the MRI and Mocart Scores were essential for a non-invasive evaluation of the new cartilage tissue, demonstrating that the use of micro-perforations and the grafting of mesenchymal cells can actually lead to a homogeneous tissue regeneration, well integrated and functionally valid. Even in the case of massive lesions, which required the use of allograft transplants, the results of the Mocart morphological radiological parameters revealed how it is possible to obtain, in certain cases, a cartilage with characteristics similar to that of hyaline; however the heterogeneity of the results in the subgroup suggested that the use of Allograft in OCL has particularly limited indications and that this method should be considered a “rescue” option.
Therapeutic approaches and surgical techniques in the treatment of osteochondral lesions of the talus are in rapid development and continuous improvement, although associated with very promising results, long-term results confirmations are still needed.
Author statement
Leonardo Puddu: Conceptualization, Writing - review & editing, Fabiana Altamore: Writing - review & editing, Alessandro Santandrea: Validation, Domenico Mercurio: Visualization, Gianfilippo Caggiari: Validation, Sabino Della Sala: Investigation, Alessandro Marinetti: Investigation, Francesco Tessarolo: Software, Formal analysis, Marta Rigoni: Software, Formal analysis, Andrea Fabio Manunta: Supervision, Fabrizio Cortese: Project administration.
Declaration of competing interest
The authors declare no conflict of interest.
Contributor Information
Leonardo Puddu, Email: leonardo.puddu@apss.tn.it.
Fabiana Altamore, Email: fabianaltamore@gmail.com.
References
- 1.Giannini S., Buda R., Faldini C. Surgical treatment of the osteochondral lesions of the talus (OLT) in young active patients. J Bone Joint Surg. 2005;87(Supp 2):28–41. doi: 10.2106/JBJS.E.00516. [DOI] [PubMed] [Google Scholar]
- 2.Marlovits S., Singer P., Zeller P., Mandl I., Haller J., Trattnig S. Magnetic resonance observation of cartilage repair tissue (MOCART) for the evaluation of autologous chondrocyte transplantation: determination of interobserver variability and correlation to clinical outcome after 2 years. Eur J Radiol. 2006;57(1):16–23. doi: 10.1016/j.ejrad.2005.08.007. [DOI] [PubMed] [Google Scholar]
- 3.Verhagen R.A., Maas M., Dijkgraaf M.G., Tol J.L., Krips R., van Dijk C.N. Prospective study on diagnostic strategies in osteochondral lesions of the talus. Is MRI superior to helical CT? J Bone Joint Surg Br. 2005;87(1):41–46. [PubMed] [Google Scholar]
- 4.Goebel L., Orth P., Müller A. Experimental scoring systems for macroscopic articular cartilage repair correlate with the MOCART score assessed by a high-field MRI at 9.4 T-comparative evaluation of five macroscopicscoring systems in a large animal cartilage defect model. Osteoarthritis Cartilage. 2012 Sep;20(9):1046–1055. doi: 10.1016/j.joca.2012.05.010. [DOI] [PubMed] [Google Scholar]
- 5.Choi Y.S., Potter H.G., Chun T.J. MR imaging of cartilage repair in the knee and ankle. Radiographics. 2008;28(4):1043–1059. doi: 10.1148/rg.284075111. [DOI] [PubMed] [Google Scholar]
- 6.Giannini S., Battaglia M., Buda R., Cavallo M., Ruffilli A., Vannini F. Surgical treatment of osteochondral lesions of the talus by open-field autologous chondrocyte implantation: a 10-year follow-up clinical and magnetic resonance imaging T2-mapping evaluation. Am J Sports Med. 2009 Nov;37(suppl 1) doi: 10.1177/0363546509349928. 112S-8S. [DOI] [PubMed] [Google Scholar]
- 7.Giannini S., Buda R., Battaglia M. One-Step repair in talar osteochondral lesions: 4-year clinical results and T2-mapping capability in outcome prediction. Am J Sports Med. 2012;5 doi: 10.1177/0363546512467622. published online December. [DOI] [PubMed] [Google Scholar]
- 8.Buda R., Castagnini F., Cavallo M., Ramponi L., Vannini F., Giannini S. “One-step” bone marrow derived cells transplantation and joint debridement for osteochondral lesions of the talus in ankle osteoarthritis: clinical and radiological outcome at 36 moths. Arch Orthop Trauma Surg. 2016 Jan;136:107–116. doi: 10.1007/s00402-015-2344-1. Epub 2015 Oct 15. [DOI] [PubMed] [Google Scholar]
- 9.Giannini S., Battaglia M., Buda R., Cavallo M., Ruffilli A., Vannini F. Surgical treatment of osteochondral lesions of the talus by open-field autologous chondrocyte implantation: a 10-year follow-up clinical and magnetic resonance imaging T2-mapping evaluation. Am J Sports Med. 2009;37(Suppl 1):112S–118S. doi: 10.1177/0363546509349928. [DOI] [PubMed] [Google Scholar]
- 10.Becher C., Thermann H. Results of microfracture in the treatment of articular cartilage defects of the talus. Foot Ankle Int. 2005;26(8):583–589. doi: 10.1177/107110070502600801. [DOI] [PubMed] [Google Scholar]
- 11.Giannini S., Buda R., Vannini F., Cavallo M., Grigolo B. One-step bone marrow-derived cell transplantation in talar osteochondral lesions. Clin Orthop Relat Res. 2009 Dec;467(12):3307–3320. doi: 10.1007/s11999-009-0885-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Giannini S., Buda R., Di Caprio F., Grigolo B. Arthroscopic autologous chondrocyte implantation in osteochondral lesions of the talus: surgical technique and results. Am J Sports Med. 2008;36:873–880. doi: 10.1177/0363546507312644. [DOI] [PubMed] [Google Scholar]
- 13.Doria C., Mosele G.R., Caggiari G., Puddu L., Ciurlia E. Treatment of early hip osteoarthritis: ultrasound-guided platelet rich plasma versus hyaluronic acid injections in a randomized clinical trial. Joints. 2017;5(3):152–155. doi: 10.1055/s-0037-1605584. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Ball St. The effect of storage on fresh human osteochondral allografts. Clin Orthop Relar Res. 2004;418:246–252. doi: 10.1097/00003086-200401000-00043. [DOI] [PubMed] [Google Scholar]
- 15.Berger G.C. Does fresh osteochondral allograft transplantation of talar osteochondral defects improve function? Clin Orthp Rel Res. 2011;469:2356–2366. doi: 10.1007/s11999-011-1813-2. [DOI] [PMC free article] [PubMed] [Google Scholar]