Arthroscopic debridement and healing stimulation
Older series described the open surgical treatment of OCDs, but recent series have concentrated on arthroscopic treatment. Generally, debridement of flaps of cartilage and removal of loose bodies are recommended. Most ankles will require some degree of synovectomy for access and this may help joint pain. Undisplaced fragments can be fixed with bone pegs, non-protruding screws or absorbable pins.
Several methods have been proposed to stimulate the growth of fibrocartilage:
- Curettage back to bleeding bone
- Chondral abrasion
- Drilling of the lesion surface(this may require a trans-malleolar portal, with a risk of fracture or new joint damage). Higashiyama et al (2000) repeated MR scans after drilling and showed resolution of oedema and sclerosis in 71%.
Schuman (2002) reported results of curettage and drilling at a mean of 5y, with good-excellent results in 86% of primary and 75% of revision procedures. Only one patient, at 10year follow-up, had osteoarthritis. A larger series of 65 patients, but with shorter mean follow-up of 3.5y was reported by Robinson et al (2003). Curettage and drilling were used at different stages of the study. Only half of their patients had few or no symptoms, while 14 had not improved. Poor results were particularly associated with cystic lesions and late presentations. However, Han et al (2006) found the results of debridement of cystic lesions and non-cystic lesions to be the same.
Tol et al (2000) reviewed studies up to 1998 and found that both curettage and curettage and drilling had success rates of around 80%, with the addition of drilling slightly better. However, the quality of reporting made it difficult to draw conclusions. The same group reported a systematic review in 2003 with similar conclusions. Subsequent case series, though frequent, have not really added much to this. Ferkel (2008) reported 50 cases from a total series of 137 patients follwed 6y after drilling. The mean AOFAS ankle score was 84/100, all patients returned to work and sport, although only 60% to the previous sporting level. Ankle scores were better in patients with minimal or no OA and where the original lesion had no separated flap or fragment.
Gobbi et al (2006) reported a RCT comparing chondroplasty, microfracture and osteochondral transplantation. Lesions of at least 1cm diameter with fragments but no cysts were included. No difference was found between any of the treatment groups at a mean of 53 (24-119) months. Only 32 patients were included, a pseudorandomisation allocation method was used and the main outcome measure was the AOFAS ankle-hindfoot score, so some caution should be used in interpreting this finding.
Lee (2009) reported second-look arthroscopies 12m after microfracture. 7-8/20 (depending on grading system) showed incomplete healing and the mean AOFAS ankle score was significantly lower in the unhealed group.
Chuckpaiwong (2008) reported the results of microfracture in 105 patients. All patients with lesions <15mm2 had satisfactory results; only one patient with a larger lesion had a good results. Choi (2009) found the same threshold of 15mm2 for poor results from microfracture or abrasion; above this value 20/25 had poor clinical results or grafting.
It probably does not matter which technique is used, and most patients will improve with simple arthroscopic debridement. We debride and curette all lesions. Drilling is used when curettage does not reach fresh bone.
Even large, deep lesions sometimes settle clinically with arthroscopic surgery (Robinson et al 2003). Repeat arthroscopic debridement did less well than primary surgery in the series of Schuman (2002) and Robinson (2003), but Savva et al (2007) obtained good results in all but one of twelve revision procedures.
Chondral and osteochondral grafting
Lesions which fail to settle or recur may be considered for further reconstructive surgery by bone and/or cartilage grafting.
Osteochondral plug grafting has been extensively used in the knee. For the talus graft may be harvested from the intercondylar notch of the femur (Mendicino 2001, Hangody 2001, al-Shaikh 2002, Scranton 2006) or the non-weightbearing surface of the talus (Sammarco 2002, Kreuz 2006). Access to the talus may require a medial malleolar or anterior tibial osteotomy. The longest follow-up is from Valderrabano (2009), who reported 12 (from an ariginal cohort of 21) patients at a mean follow up of 6y. Mean VAS pain score decreased from 5.9-3.9/10 - only 2 patients were pain-free. In addition, 5 patients had mild pain and 2 severe pain in the donor knee. Mean AOFAS ankle score improved from 45.9-80.2/100 and Tegner activity score from 0.4 to 1.25 (compared with 2.3 pre-injury). Six patients returned to some sport. All patients had abnormalities on MRI.
Hangody (2001) reported 34/36 excellent or good results according to the Hannover score at 2-7 years (mean 4.2 years). Clinical details were not reported. Follow-up MR scans and arthroscopy showed congruent joint surface and incorporation of graft in unspecified numbers of patients.
Kreuz (2006) reported improvement in mean AOFAS ankle/hindfoot score from 54 pre-op to 89 at 4 years. Scranton (2006) reported 90% good-excellent results even in large cystic lesions. Few complications have been reported at the donor site in either knee or ankle in most series, but Reddy et al (2007) reported significant knee symptoms, mainly instability, in 4/11 patients.
An alternative is the use of autologous cultured chondrocyte grafts applied under a periosteal flap (Giannini 2001). Bone graft may be used to fill underlying voids. Giannini reported improvement from a mean AOFAS ankle-hindfoot score of 32 pre-operatively to 91 at 24 months. Defect sizes ranged from 2.2-4.3cm 2 and arthroscopic biopsies in 5 patients showed healthy cartilage. Giannini (2009) re-reported this series at 10 years, Whittaker (2005) reported success in 9/10 patients at follow-up averaging 2 years; the Mazur ankle score increased from 51/90-74/90. Nine had arthroscopic confirmation of graft incorporation. Baums et al (2006) reported 12 patients followed up for mean 63 (48-84)m. The mean Hannover score improved from 40.4 pre-op to 85.5 and the mean AOFAS ankle/hindfoot score from 43.5 to 88.4. 11/12 grafts were incorporatd at final follow-up, although the articular surface was irregular in 4.
The MACI technique incorporates the chondrocytes into a scaffold to avoid the technical problems of periosteal flap fixation. Giannini (2008) described an arthroscopic technique without formal fixation. 46 patients were followed for a mean of 3y. The AOFAS score improved from 57 to 87/100. Age and previous surgery were negatively correlated with outcome but lesion size and location and the need for cancellous graft ad no effect on outcome. 20/29 who played sport returned to the same level, 5 reduced the level of sport and 4 gave up. Schneider (2009) reported 20 patients using an open technique. At a mean of 21 months' follow-up, the AOFAS score had improved from 60-87/100 and pain had improved in 14, was unchanged in 5 and worse in 1. Three patients had repeat debridements.
Autologous cultured chondrocyte grafts gave significantly better results in a RCT in the knee (Bartlett et al 2005), but no such study has been done in the knee. At the moment the reported results of both techniques in the talus is similar, but osteochondral grafting is more available to the average foot and ankle surgeon.
Raikin (2009) used fresh osteochondral allografts to repair very large cystic OLTs in 15 patients. At 4.5years follow-up, the AOFAS score was 83/100 and the VAS pain score 3.3/10. Two patients had undergone ankle fusion and all the remaining grafts showed some resorption and collapse.