Faculty Bibliography

PURPOSE:To evaluate morphological alterations, microarchitectural disturbances, and the extent of bone marrow access to the subchondral bone marrow compartment using micro-computed tomography analysis in different bone marrow stimulation (BMS) techniques. METHODS:Nine zones in a 3 × 3 grid pattern were assigned to 5 cadaveric talar dome articular surfaces. A 1.00-mm microfracture awl (s.MFX), a 2.00-mm standard microfracture awl (l.MFX), or a 1.25-mm Kirschner wire (K-wire) drill hole was used to penetrate the subchondral bone in each grid zone. Subchondral bone holes and adjacent tissue areas were assessed by micro-computed tomography to analyze adjacent bone area destruction and communicating channels to the bone marrow. Grades 1 to 3 were assigned, where 1 = minimal compression/sclerosis; 2 = moderate compression/sclerosis; 3 = severe compression/sclerosis. Bone volume/total tissue volume, bone surface area/bone volume, trabecular thickness, and trabecular number were calculated in the region of interest. RESULTS:Visual assessment revealed that the s.MFX had significantly more grade 1 holes (P < .001) and that the l.MFX had significantly more poor/grade 3 holes (P = .002). Bone marrow channel assessment showed a statistically significant increase in the number of channels in the s.MFX when compared with both K-wire and l.MFX holes (P < .001). Bone volume fraction for the s.MFX was significantly less than that of the l.MFX (P = .029). CONCLUSIONS:BMS techniques using instruments with larger diameters resulted in increased trabecular compaction and sclerosis in areas adjacent to the defect. K-wire and l.MFX techniques resulted in less open communicating bone marrow channels, denoting a reduction in bone marrow access. The results of this study indicate that BMS using larger diameter devices results in greater microarchitecture disturbances. CLINICAL RELEVANCE:The current study suggests that the choice of a BMS technique should be carefully considered as the results indicate that smaller diameter hole sizes may diminish the amount of microarchitectural disturbances in the subchondral bone.

BACKGROUND:Autologous osteochondral transplantation (AOT) has an inherent risk of donor site morbidity (DSM). The reported rates of DSM vary from 0% to 50%, with few studies reporting clinical or imaging outcomes at the donor site as a primary outcome and even fewer report these outcomes when a biosynthetic plug backfill is employed. Although TruFit (Smith & Nephew, Andover, MA) plugs have been removed from the market for regulatory purposes, biphasic plugs (including TruFit plugs) have been used for several years and the evaluation of these is therefore pertinent. METHODS:Thirty-nine patients who underwent forty AOT procedures of the talus, with the donor graft being taken from the ipsilateral knee, were included. Postoperative magnetic resonance imaging (MRI) was used to assess the donor site graded with magnetic resonance observation of cartilage repair tissue (MOCART) scoring. Lysholm scores were collected preoperatively, at the time of magnetic resonance imaging (MRI), and again at 24 months and at final follow-up to assess clinical outcomes. Statistical analysis was performed to establish if there was any correlation between MRI assessment of the donor site and clinical outcomes. The mean patient age was 36.2 ± 15.7 years with a mean follow-up of 41.8 ± 16.7 months. RESULTS:All patient donor site defects were filled with OBI TruFit biphasic plugs. DSM was encountered in 12.5% of the patient cohort at 24 months, and in these patients, the Lysholm score was a mean 87.2 ± 5.0. At final follow-up, DSM was reduced to 5%. Lysholm scores for the entire cohort were 98.4 ± 4.6 and 99.4 ± 3.1 at 24 months and final follow-up, respectively. MRI of the donor sites were taken at an average of 18.1 ± 13.5 (range, 3-48) months postoperatively and the mean MOCART score was 60.0 ± 13.5. No correlation was found between the MOCART score and Lysholm outcomes at the donor knee (P = .43, r = 0.13). CONCLUSION/CONCLUSIONS:Low incidence of DSM and good functional outcomes were achieved with AOT. Additionally, MRI findings did not predict clinical outcomes in our study. LEVEL OF EVIDENCE/METHODS:Level IV, retrospective case series.

PURPOSE:To identify potential cysts using magnetic resonance imaging (MRI) after autologous osteochondral transplantation (AOT) for osteochondral lesions of the talus (OLTs) as well as to determine the effect of cysts on short-term clinical outcomes. METHODS:Eighty-nine MRI scans of 37 patients who had AOT for an OLT were evaluated. Radiographic variables examined included cyst presence, cyst location, bone edema, and cartilage integrity. Patient clinical variables recorded and examined for association with the presence of a cyst included gender, age, preoperative lesion size, size and number of osteochondral graft used, symptoms reported, and pre- and postoperative Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) scores measured at final follow-up. RESULTS:Twenty-four patients (64.8%) had MRI evidence of cystic change after AOT for an OLT at a mean MRI follow-up time of 15 months after surgery (range 2-54). Patients with presence of a cyst after surgery were older (mean age, 42.7 years) than those without cysts (mean age, 32.7 years) (P = .041), and among patients with a cyst, older patients more often had involvement of the subchondral plate (57.3 v 36.7 years) (P < .001). No other variables associated with cyst formation had statistical significance. Mean patient FAOS scores increased from 50 (±19) preoperatively to 87 (±8) postoperatively. Mean SF-12 scores increased from 52 (±18) preoperatively to 85 (±6) postoperatively. Patients not identified as having a cyst had lower SF-12 (P = .028) and FAOS (P = .032) preoperative scores and more improvement in SF-12 (P = .006) and FAOS (P = .016) scores than patients with cysts. CONCLUSIONS:Postoperative cyst formation on MRI was found to be a common occurrence after AOT for OLT. Although increasing age was related to increased cyst prevalence, the clinical impact of cyst formation was not found to be significant at short-term follow-up. Continued long-term longitudinal follow-up of postoperative cysts is needed. LEVEL OF EVIDENCE:Level IV, prognostic case series.

We conducted a wide-ranging review of the literature regarding osteochondral lesions of the ankle, with the aim of presenting the current concepts, treatment options, trends and future perspectives relating to this topic.

The objective of this study was to evaluate the effect of chemical tissue bonding (CTB) on adhesion strength, fluid permeability, and cell viability across a cartilaginous graft-host interface in an in vitro autologous chondral transplant (ACT) model. Chitosan-based cross-linkers; Chitosan-Rose Bengal [Chi-RB (Ch-ABC)], Chitosan-Genipin [Chi-GP (Ch-ABC)], and Chitosan-Rose Bengal-Genipin [Chi-RB-GP (Ch-ABC)] were applied to bovine immature cartilage explants after pre-treatment with surface degrading enzyme, Chondroitinase-ABC (Ch-ABC). Adhesion strength, fluid permeability and cell viability were assessed via mechanical push-out shear testing, fluid transport and live/dead cell staining, respectively. All three chitosan-based cross-linkers significantly increased the adhesion strength at the graft-host interface, however, only a statistically significant decrease in fluid permeability was noted in Chi-GP (Ch-ABC) specimen compared to untreated controls. Cell viability was maintained for 7 days of culture across all three treatment groups. These results show the potential clinical relevance of novel chitosan-based hydrogels in enhancing tissue integration and reducing synovial fluid penetration after ACT procedures in diarthoidal joints such as the knee and ankle. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1139-1146, 2016.

PURPOSE:To determine if functional outcomes and magnetic resonance imaging (MRI) outcomes were significantly different between patients receiving primary autologous osteochondral transplantation (AOT) and patients receiving secondary AOT surgery after failed microfracture. METHODS:A group of 76 patients enrolled into the Foot and Ankle Service between 2006 and 2012 was retrospectively analyzed. Patient-reported outcomes were evaluated in 76 patients using the Foot and Ankle Outcome Score (FAOS). Superficial and deep tissues at the repaired defect site, as well as the adjacent normal cartilage, were analyzed using quantitative T2 mapping MRI. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) allowed for morphological evaluation of the repair tissue. The mean clinical follow-up time was 51 ± 23 months (range, 12 to 97 months), and the mean MRI follow-up time was 26 months (range, 24 to 36 months). RESULTS:Twenty-two patients received primary AOT and 54 received secondary AOT after failed microfracture. Patient characteristics between groups were similar with regard to age, gender, lesion size, and follow-up time. The mean postoperative FAOS was 10 points higher in the primary AOT group (83.2 ± 17.0) compared with the secondary AOT group (72.4 ± 19.4) (P = .01). Regression analysis showed that secondary AOT patients preoperative to postoperative change in FAOS was 9 points lower than in primary AOT patients after adjustment for age, preoperative FAOS, and lesion size (P = .045). The mean MOCART score, superficial T2 and deep T2 values, and the difference between normal and repair cartilage T2 values were not significantly different between groups. Lesion size was negatively correlated with MOCART scores (ρ = -0.2, P = .04), but positively correlated with difference in T2 values between repair and adjacent normal cartilage in the superficial layer (ρ = 0.3, P = .045). CONCLUSIONS:Primary AOT shows better functional outcomes compared with secondary AOT after failed microfracture in patients with similar characteristics and lesion size. No significant differences in T2 mapping relaxation times and MOCART scores were identified. LEVEL OF EVIDENCE:Level III, case control study.

Arthroscopic and open ankle arthrodesis have been compared in very few studies, and no consensus has been reached regarding the incidence of postoperative revision surgery associated with each technique. The purpose of the present study was to compare these 2 approaches for the incidence of postsurgical operations. Patients who had undergone either arthroscopic or open ankle arthrodesis were identified between January 2005 to December 2011 in the PearlDiver(™) database using a predetermined algorithm and searched for the following postsurgical operations: revision ankle arthrodesis, midfoot arthrodesis, and hindfoot arthrodesis. In the current database, 7322 cases were performed with an open technique and 1152 arthroscopically. The incidence of revision arthrodesis was not significantly different statistically between the 2 techniques. However, the incidence of subsequent adjacent joint arthrodesis was greater for the open cohort (5.6% versus 2.6%; odds ratio 2.17, 95% confidence interval 1.49 to 3.16). In the open cohort, the incidence of hindfoot arthrodesis was greater than the incidence of midfoot arthrodesis (3.9% versus 1.6%, odds ratio 2.43, 95% confidence interval 1.95 to 3.01). The results showed that although open ankle arthrodesis is more commonly performed, it is associated with a greater incidence of subsequent adjacent joint arthrodesis specifically in the hindfoot.

Chronic lateral ankle instability can occur in a subset of patients following ankle inversion sprains. Operative treatment to restore stability in the ankle and hindfoot and to prevent further degenerative changes may be indicated in cases in which nonoperative treatment has failed. Anatomical direct repair with use of native ligament remnants with or without reinforcement of the inferior retinaculum is the so-called gold standard operative strategy for the treatment of lateral ankle instability. The procedure has shown promising short and long-term outcomes. Candidates for the procedure have ligament remnants of sufficient quality that are amendable to direct repair. Anatomical reconstruction with use of autograft or allograft is reserved for patients with insufficient ligament remnants to fashion a direct repair, failed previous lateral ankle repair, high body mass index, or generalized ligamentous laxity. A wide variety of autografts have been described, each with potential advantages and disadvantages. These procedures can provide good-to-excellent short-term outcomes. However, there is no available information on their long-term clinical results. Non-anatomical lateral ligament reconstruction typically involves the use of the adjacent peroneal brevis tendon and has been applied in cases in which only poor-quality ligament remains. The procedure can provide good to excellent short-term outcomes, although reported long-term outcomes have differed among studies. The particular tendon used for the graft should be carefully considered given the potential alterations in the kinematics of the ankle and hindfoot. Arthroscopic ligament repair is becoming increasingly popular as it is minimally invasive. This procedure is restricted to patients who have good-quality ligament remnants. Good-to-excellent clinical outcomes have been reported after short and long-term follow-up, although a relatively high rate of complications-including nerve damage-has been reported following the procedure and therefore warrants further investigation before widespread adoption can be advocated.

PURPOSE/OBJECTIVE: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/CONCLUSIONS: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/METHODS:Retrospective case series, Level IV.