Address for Correspondence
Mr LE Dodd
26 Blackdown Close,
Pyrford,
Surrey,
GU22 8LQ.
Tel: 07900 248 253
Email: docdodd@doctors.org.uk
Abstract:
We prospectively reviewed the results of a consecutive group of patients with ankle osteoarthritis who underwent arthroscopic debridement for symptoms refractory to conservative measures. The radiological changes preoperatively were graded using the system advanced by Van Dyke and all cases had moderate to severe arthritic changes.
We used the validated Manchester Oxford Foot and Ankle questionnaire to score symptoms pre operatively and postoperatively following a minimum of 6 months follow up (mean of 13 months).
The arthroscopic treatment consisted a joint washout and a debridement of anterior osteophytes. There was no significant improvement in the post operative scores achieved for the walking and social interaction domains (p>0.05), however there was an improvement in the pain scores. Using a validated questionnaire we demonstrate a modest improvement in ankle arthritis symptoms following arthroscopic debridement. This fact should be stressed to patients due to have arthroscopic debridement in the presence of arthritis.
J.Orthopaedics 2011;8(2)e12
Keywords: Osteoarthritis; Arthroscopy; Outcomes
Introduction
Epidemiological studies of ankle osteoarthritis show that primary ankle osteoarthritis is a relatively uncommon pathology when compared to the hip and knee joints.
The unique biomechanics and cartilage physiology may play a large part in this observation with studies demonstrating the ankle as having comparatively thinner cartilage but with a higher compressive modulus1 than the other major lower limb joints.
The commonest cause of ankle osteoarthritis is post traumatic degenerative change following fractures. Primary osteoarthritis accounts for 7-10% of the cases of ankle osteoarthritis with trauma accounting for up to 70% of cases2. The diagnosis of ankle osteoarthritis is clinical with supporting radiological evidence. Radiographs of the ankle have a tendency to underestimate the degree of early articular degeneration placing more emphasis on the clinical assessment3.Management is aimed at achieving symptom control and delaying the progress to the definitive treatments of arthrodesis or arthroplasty. The available options in non surgical management include analgesia, bracing, shoe modifications and distraction therapy, with arthroscopic debridement occupying the gap between the non surgical and the definitive measures.Arthroscopic debridement has been shown to produce satisfactory symptom control allowing return to physical activities in patients with early arthritis4, while other studies have questioned the benefit5. In patients with advanced osteoarthritis, arthroscopic debridement is felt to have modest effect at best with most surgeons opting for arthrodesis or arthroplasty4,5.Current evidence of arthroscopic debridement in ankle osteoarthritis have been limited by small numbers and inclusion of patients with osteophyte impingement for which arthroscopy has been shown to produce favourable results. In addition, to our knowledge none of the postoperative assessments have been performed using validated questionnaires.We prospectively evaluated patients who had arthroscopic debridement for osteoarthritis focussing on the patient outcome score using the validated modified Manchester Oxford Foot and Ankle Questionnaire (MOXFQ)6,7.
Patients and methods
We prospectively assessed 17 patients representing 18 ankles undergoing ankle arthroscopy. Inclusion criteria for the study were patients with radiological evidence of osteoarthritis with symptoms refractory to conservative measures and undergoing arthroscopy under the senior author (SHP). The mean age of the patients was 54.5 years (range 39–75 years). There were 7 females and 11 males (bilateral in 1 case). All the patients had a preoperative MOXFAQ evaluation without assistance to score their symptoms. The operations were carried out in the period May 2006-October 2009 as day case procedures under the senior author SHP. All the patients had pre operative radiographs which were assessed by a consultant radiologist and scored using the system described by CN van Dyke8. Intraoperatively the extent of cartilage destruction was classified using the outerbridge system.
Table 1.
Grade Description
0 No OA, normal joint or subchondral sclerosis
I Osteophytes without narrowing of the joint space
II Narrowing of the joint space with or without osteophytes
III Deformation or (sub)total disappearance of the joint line
Radiological classification of osteoarthritic changes in the ankle
Surgical technique
A standard arthroscopic technique was adopted with a thigh tourniquet applied. Anterolateral and anteromedial portals were created using a ‘cut and spread’ technique. The articular cartilage was assessed and graded. In all cases anterior osteophytes were debrided and scarring removed with a shaver. The joint was then irrigated and finally 20mls of 0.5% marcain was instilled into the joint and the portals. Closure was with 4.0 ethilon and the ankle portals were covered with primapore dressing then wrapped in wool and crepe bandaging. Post operatively all the patients had a 5 day period of elevation and were reviewed in the physiotherapy clinic at 2 weeks to commence proprioception, range of motion and gastrocnemius stretching exercises. The scores form the MOXFAQ where converted to metric units and statistically analysed using the Analyse-it® software package. Wilcoxon signed rank test was used to analyse the data.
Results
We identified 17 patients representing 18 ankles for this study. Of this initial number 3 patients were lost to follow up post operatively leaving 15 ankles for analysis. The mean follow up period was 13.6 months with a range of 6-36 months. Using the outerbridge classification, 14 patients had grade 4 osteoarthritis, 1 had grade 3, 1 had grade 2 and in 2 patients the osteoarthritis grade was not documented. Post operatively we assessed the patients for nerve injury and sought any signs of infection. The only complication was in 1 patient who suffered persistent altered sensation over the dorsum of his foot representing an overall complication rate of 5%. There were no instances of deep or superficial infections.
Analysis of the 3 MOXFAQ domains walking and standing(WS), pain(P) and social interaction(SI) was performed by converting the scores to metric units (doll et al). The pre operative and postoperative scores are shown in the table below.
Table 2.
|
Walking/standing |
Pain |
Social interaction |
Pre-op |
62.2 |
63.3 |
42 |
Post-op |
60.1 |
53 |
43 |
Difference |
2.1 |
10.3 |
-1 |
Pre- and post surgery MOXFAQ scores and the score change.Statistically analysing the pre and post operative scores using the Wilcoxon rank test showed that the improvement in the pain at rest domain was not significant with a p value of 0.083. The social interaction and walking/standing domains showed minimal change in the MOXFAQ scores with statistical analysis generating p values of 0.85 and 0.84 respectively.
Figure 1.
MOXFAQ scores separated into the 3 domains and compared pre- and post surgery.
WS1,WS2 - walking /standing domain scores pre- and post surgery respectively.
P1,P2 - pain domain scores pre- and post surgery respectively.
SI1,SI2 - social interaction domain score pre and post surgery.
Discussion
With the aging populations in the west there will be an increase in the rate and incidence of all forms of osteoarthritis including within the ankle joint1,2,5. Management of early ankle osteoarthritis is mainly non surgical with modified footwear, analgesia and orthoses being the main treatments. However, in intermediate OA there is still no consensus on the most appropriate management and arthroscopy is one of the surgical options which has been applied with varying results5,13,14,15. The MOXFAQ has been demonstrated to be a responsive and focused tool in the assessment of outcomes following foot and ankle surgery6,7. It is for this reason we opted to use the questionnaire to closely assess the effect of arthroscopic debridement in patients with radiographic and clinically moderate osteoarthritis. Previous studies reviewing the effect of arthroscopy have suggested that the results are often modest with upto 66% improvement recorded. These studies have been however more clinically driven in the assessment of the results and the need to present a patient centred perspective was the driving force behind this analysis.
We initially analysed the correlation of the symptomatology to the xray findings and in line with previous studies found no correlation between the extent of radiological degradation, the symptoms suffered by the patient nor the actual extent of articular cartilage destruction viewed arthroscopically16. We analysed the results of the three MOXFAQ domains separately. Post operatively we found a slight improvement in the walking and standing domain with the mean scores dropping from 62.1 to 60. This improvement was not statistically significant. On the social interaction there was a mean deterioration from 42 to 43 but this small effect was not statistically significant. In the pain domain there was a reduction in the overall score from 52 to 42 but again this did not achieve statistical significance. The reduction in the MOXFAQ scores suggests that early to medium effects of ankle arthroscopy in patients with osteoarthritis are positive with regards to pain relief however the social interaction and walking domains remain largely unchanged. This, however, was not borne out statistically.
Our study is limited by small numbers exacerbated by the patients lost to follow up, and the relatively short follow up period. However weight is added by using a standardised surgical technique performed by a single surgeon and the use of a validated questionnaire. Ankle arthroscopy may be used as a temporising pain control measure in patients with osteoarthritis. In our review the majority of patients reported an improvement in their pain at rest and would have had the surgery again. This effect was not statistically significant. Although pain at rest was improved, pain on walking and standing remained unchanged and this would be an important point to stress to patients due to undergo the procedure. Due to the small numbers the results should be interpreted with caution and a further large number study is still required. Ankle arthroscopic debridement should be considered in patients with refractory pain with anterior impingement who are not yet ready for either arthrodesis or arthroplasty.
References
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