Ankle images digital analysis (AIDA): digital measurement of joint space width and subchondral sclerosis on standard radiographs

A new magnetic internal distractor: cadaveric study of changes in trapeziometacarpal joint forces

Distraction is a new treatment for trapeziometacarpal joint osteoarthritis. The purpose of this study was to test the efficiency of magnetic distraction using a new internal distractor in cadavers. The distractor consists of two magnets embedded inside titanium capsules that are implanted on either side of the trapeziometacarpal joint with the same poles facing each other, so that the force between the magnets distracts the joint. Intra-articular forces were recorded pre-implantation, immediately after implantation and again 10 minutes later. We also studied the changes in the forces before and after the procedure in different thumb positions. Our findings show that the trapeziometacarpal joint could be offloaded in all the studied trapeziometacarpal positions.

[Mid- and long-term effectiveness analysis of distraction arthroplasty in treatment of moderate to severe ankle arthritis]

OBJECTIVE

To investigate the mid- and long-term effectiveness of external fixator distraction arthroplasty in the treatment of moderate to severe ankle arthritis.

METHODS

The clinical data of 23 patients with moderate to severe ankle arthritis treated with external fixation distraction arthroplasty who met the selection criteria between January 2007 and November 2019 were retrospectively analyzed. There were 20 males and 3 females; the age ranged from 21 to 65 years, with an average age of 43.7 years. Etiology included 8 cases of primary ankle arthritis, in which 5 cases combined with varus deformity; 15 cases of traumatic ankle arthritis, the cause of injury was 5 cases after ankle fracture surgery, 3 cases after Pilon fracture surgery, 5 cases of chronic ankle instability and repeated sprain, and 2 cases of other causes. According to Takakura staging system, there were 4 cases of stage ⅢA, 12 cases of stage ⅢB, and 7 cases of stage Ⅳ; according to Giannini staging system, there were 5 cases of stage Ⅱ and 18 cases of stage Ⅲ; according to Cheng staging system, 16 cases were in stage Ⅲ, and 7 cases stage Ⅳ. American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and visual analogue scale (VAS) score were used to evaluate the improvement of ankle pain and function before operation and at last follow-up, and the data were analyzed according to different etiological groups. At last follow-up, the surgical results were evaluated subjectively and objectively. The changes of ankle joint space before operation and at last follow-up were compared. The patients were divided into two groups according to their age: ≤45 years old group [young group, 10 cases, aged (35.62±7.41) years old] and >45 years old group [middle-aged and elderly group, 13 cases, aged (54.20±6.20) years old]. The AOFAS ankle-hindfoot score and VAS score were compared before and after operation between the two groups, and the influence of age on distraction arthroplasty was analyzed.

RESULTS

The external fixator was removed after 3 months of continuous distraction,12 patients got infection around the wire tunnels. All the 23 patients were followed up 13-143 months, with an average of 56.9 months; the follow-up time was (43.46±32.77) months and (69.80±37.79) months in the young group and middle-aged and elderly group, respectively. At last follow-up, the AOFAS ankle-hindfoot score and VAS score significantly improved when compared with those before operation ( P<0.05). According to etiological analysis, there was no significant difference in AOFAS ankle-hindfoot score and VAS score before and after operation ( P>0.05) in Pilon fracture patients, while the significant difference was found in remaining patients ( P<0.05). There was significant difference in AOFAS ankle-hindfoot score before operation between the young group and the middle-aged and elderly group ( t=2.110, P=0.040), but no significant difference in preoperative VAS score and the differences in VAS score and AOFAS ankle-hindfoot score before and after operation between the two groups ( P>0.05). The subjective and objective results of pain evaluation at last follow-up showed that 4 patients had no pain, 12 patients had moderate pain relief, 5 patients had mild pain relief, and 2 patients had no significant pain relief; among the 10 patients who were followed up more than 5 years, there were 2, 5, 2, and 1 patient, respectively; 2 patients who were followed up more than 10 years had moderate pain relief. At last follow-up, the ankle joint space was (3.7±0.4) mm, which significantly increased when compared with before operation [(1.5±0.2) mm] ( t=1.791, P=0.002). The ankle joint space was (2.9±0.5) mm in 10 patients who were followed up more than 5 years, and 3.3 mm and 3.0 mm in 2 patients who were followed up more than 10 years.

CONCLUSION

Distraction arthroplasty of the ankle joint can achieve satisfactory results in patients with moderate to severe ankle arthritis (except for arthritis caused by Pilon fracture), and age has no significant effect on distraction arthroplasty.

Joint distraction for osteoarthritis: clinical evidence and molecular mechanisms

Joint distraction, the prolonged mechanical separation of the bones at a joint, has emerged as a joint-preserving treatment for end-stage osteoarthritis, with the gradually growing promise of implementation in regular clinical practice. Joint distraction of the knee has been most extensively studied, with these studies showing prolonged symptomatic improvement in combination with repair of cartilage tissue in degenerated knee joints, supporting the concept that cartilage repair can translate into real clinical benefit. The reversal of tissue degeneration observed with joint distraction could be the result of one or a combination of various proposed mechanisms, including partial unloading, synovial fluid pressure oscillation, mechanical and biochemical changes in subchondral bone, adhesion and chondrogenic commitment of joint-derived mesenchymal stem cells or a change in the molecular milieu of the joint. The overall picture that emerges from the combined evidence is relevant for future research and treatment-related improvements of joint distraction and for translation of the insights gained about tissue repair to other joint-preserving techniques. It remains to be elucidated whether optimizing the biomechanical conditions during joint distraction can actually cure osteoarthritis rather than only providing temporary symptomatic relief, but even temporary relief might be relevant for society and patients, as it will delay joint replacement with a prosthesis at an early age and thereby avert revision surgery later in life. Most importantly, improved insights into the underlying mechanisms of joint repair might provide new leads for more targeted treatment options.

Ankle distraction arthroplasty (ADA): A brief review and technical pearls

Ankle distraction arthroplasty (ADA) is a procedure based on the concept that mechanical unloading of an arthritic joint will initiate a healing response in the subchondral bone and articular cartilage. ADA utilizes the patient's own healing response, preserves joint motion, and is a great option for patients with osteoarthritis who are not ready for prosthetic arthroplasty or fusion. The procedure is well described and technically simple and adjunctive biologic therapies are exciting for joint regeneration. Complications are minor, and more serious adverse events are avoidable. Supramalleolar osteotomy pairs well with ankle distraction but requires some analysis and planning.

Current Advancements in Ankle Arthrodiastasis

Ankle arthrodiastasis offers an option for patients with end-stage primary or posttraumatic ankle osteoarthritis. The process allows for a joint salvage procedure as an alternative to arthrodesis or ankle implant arthroplasty. The distraction within the joint optimizes the intraarticular environment to permit equilibration of hydrostatic pressure, promoting subchondral morphoangiogenesis, and decreases subchondral sclerosis, thereby mitigating pain. This article highlights new advances and useful adjunctive procedures in this interesting approach to the management of ankle pain secondary to loss of functional joint surface.

Increased Osseous (99m)Tc-DPD Uptake in End-Stage Ankle Osteoarthritis: Correlation Between SPECT-CT Imaging and Histologic Findings

BACKGROUND

We analyzed the histopathologic findings in end-stage osteoarthritic ankle joint tissue that display increased uptake of bone-seeking radiotracer in single-photon emission computed tomography-computed tomography (SPECT-CT) imaging.

METHODS

Six consecutive patients with end-stage osteoarthritis undergoing total ankle replacement received preoperative SPECT-CT imaging using (99m)Technetium dicarboxypropane diphosphonate ((99m)Tc-DPD). Using imaging data for stratification, osteochondral tissue sections were prepared from SPECT-positive (+) and -negative (-) areas of tibial and talar resection specimens. Histomorphometric analyses of osteoblast numbers, collagen deposition, and cartilage degeneration were performed on hematoxylin and eosin, van Gieson's and Safranin-O stained tissue sections. Osteoclast activity was visualized using tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Increased (99m)Tc-DPD uptake was observed exclusively subjacent to the subchondral bone plate of tibial and talar joint compartments. SPECT(-) tissues displayed typical fatty marrow morphology containing mainly collagen-positive blood vessels and few marrow and bone-lining cells. SPECT(+) tissues were characterized by increased numbers of active bone-lining osteoblasts depositing collagen fibers. Collagen area fraction of subchondral bone marrow was significantly increased in SPECT(+) (0.52 ± 0.21) compared with SPECT(-) (0.29 ± 0.13) tissues (P = .30). Multinucleated TRAP(+) osteoclasts were absent from bone formation sites, but associated with vascular structures invading articular cartilage through the subchondral bone plate. Increased (99m)Tc-DPD uptake was specifically and strongly correlated with increased osteoblast numbers (P = .011), and with collagen area fraction (P = .030) but not with Mankin score (P = .202), or with osteoclast number (P = .576).

CONCLUSION

Subchondral bone tissues in SPECT(+) areas of end-stage ankle osteoarthritis were histologically characterized by increased osteoblast-mediated bone formation in the absence of functional osteoclasts, and increased cellularity and collagen deposition in marrow tissues.

CLINICAL SIGNIFICANCE

Our findings suggest a pathologic bone-remodeling process in end-stage ankle OA areas with increased (99m)Tc-DPD uptake.

Intermediate-term follow-up after ankle distraction for treatment of end-stage osteoarthritis

BACKGROUND

Treatment of end-stage ankle osteoarthritis remains challenging, especially in young patients. Initial reports have shown early benefits of joint distraction for the treatment of ankle osteoarthritis. We report the five to ten-year results of a previously described patient cohort following ankle distraction surgery.

METHODS

All thirty-six patients who had undergone ankle distraction surgery between December 2002 and October 2006 were contacted. Patients were evaluated by a clinical investigator and completed the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) surveys. Radiographs as well as computed tomography and magnetic resonance imaging scans of the ankles were obtained at the follow-up visits.

RESULTS

Twenty-nine patients (81%) were followed for a minimum of five years (mean and standard deviation, 8.3 ± 2.2 years). Sixteen (55%) of the twenty-nine patients still had the native ankle joint whereas thirteen patients (45%) had undergone either ankle arthrodesis or total ankle arthroplasty. Positive predictors of ankle survival included a better AOS score at two years (hazard ratio [HR] = 0.048, 95% confidence interval [CI] = 0.0028 to 0.84, p = 0.04), older age at surgery (HR = 0.91, 95% CI = 0.83 to 0.99, p = 0.04), and fixed distraction (HR = 0.094, 95% CI = 0.017 to 0.525, p < 0.01). Radiographs and advanced imaging revealed progression of ankle osteoarthritis at the time of final follow-up.

CONCLUSIONS

Ankle function following joint distraction declines over time. Patients should be well informed of the commitment that they must make during the treatment period as well as the long-term results after surgery.

Radiographic evaluation of posttraumatic osteoarthritis of the ankle: the Kellgren-Lawrence scale is reliable and correlates with clinical symptoms

OBJECTIVE

To assess reliability and construct validity of the Kellgren-Lawrence (K&L) scale in posttraumatic ankle osteoarthritis (OA); additionally evaluate the validity of including tibiotalar tilting in the scale.

METHOD

One-hundred and fifty ankle radiographs (75 patients, unilateral malleolar fractures) evaluated at average of 18 years after surgery. American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot (HF) score and pain (visual analog scale) were recorded. Grading of OA according to K&L criteria and identification of OA features was performed on standardized radiographs by four physicians. Minimal joint space width, sclerosis, and talar tilt angle were quantified by digital measurements. A modified K&L scale including talar tilting is presented. Validity of original and modified scale was evaluated and expressed as ability to (1) Identify those with clinical symptoms of ankle OA; and (2) Distinguish between different degrees of fracture severity.

RESULTS

Inter- and intra-observer reliability of OA assessment according to K&L were good (ICC 0.61 and 0.75). Original and modified K&L grades significantly increased with decreasing AOFAS ankle-HF scores and greater pain. A talar-tilt angle > 2° compared with ≤ 2° in grade 3 was associated with significantly higher pain levels (VAS pain 4.2 vs 1.4, respectively; mean difference 2.8, 95% CI 0.5-5.1). More severe fracture patterns at time of surgery were more often in patients with the highest K&L grades.

CONCLUSIONS

The K&L scale is a valid and reliable radiographic grading system for assessment of ankle OA. Inclusion of the talar tilt angle might allow for better differentiation with respect to clinical outcomes.

Minimum distraction gap: how much ankle joint space is enough in ankle distraction arthroplasty?

BACKGROUND

The success of ankle distraction arthroplasty relies on the separation of the tibiotalar articular surfaces.

QUESTION/PURPOSE

The purpose of this study was to find the minimum distraction gap needed to ensure that the tibiotalar joint surfaces would not contact each other with full weight-bearing while under distraction.

METHODS

Circular external fixators were mounted to nine cadaver ankle specimens. Each specimen was then placed into a custom-designed load chamber. Loads of 0, 350, and 700N were applied to the specimen. Radiographic joint space was measured and joint contact pressure was monitored under each load. The external fixator was then sequentially distracted, and the radiographic joint space was measured under the three different loads. The experiment was stopped when there was no joint contact under 700N of load. The radiographic joint space was measured and the initial (undistracted) radiographic joint space was subtracted from it yielding the distraction gap. The minimum distraction gap (mDG) that would provide total unloading was calculated.

RESULTS

The average mDG was 2.4 mm (range, 1.6 to 4.0 mm) at 700N of load, 4.4 mm (range, 3.7 to 5.8 mm) at 350N of load, and 4.9 mm (range, 3.7 to 7.0 mm) at 0N of load.

CONCLUSION

These results suggest that if the radiographic joint space of on a standing X-ray of an ankle undergoing distraction arthroplasty shows a minimum of 5.8 mm of DG, then there will be no contact between joint surfaces during full weight-bearing. Therefore, 5 mm of radiographic joint space, as recommended historically, may not be adequate to prevent contact of the articular surfaces during weight-bearing.

Ankle joint distraction arthroplasty: why and how?

For select patients, distraction ankle arthroplasty may be a promising treatment approach for ankle osteoarthritis; however, there is still limited literature addressing its efficacy and clinical long-term results. In this article, the literature regarding the outcome after ankle distraction arthroscopy is reviewed, the indications and contraindication for this procedure are listed, our surgical technique is described, and our preliminary results with this procedure are presented.

Hinged external fixation distraction for treatment of first metatarsophalangeal joint arthritis

Treatment for hallux rigidus varies from joint preservation to joint destructive procedures. The objective of the present study was to report an alternative method of treatment of hallux rigidus using hinged external fixation distraction of the first metatarsophalangeal joint and to present our surgical technique. Ten distractions were performed in 9 patients (9 female feet [90%] and 1 male foot [10%]). The mean age at surgery was 41.0 (range 20 to 64) years. All patients had stage II or III hallux rigidus on the Regnauld classification system for hallux rigidus. The patients were evaluated clinically and radiographically before and after the distraction treatment. The mean period of fixation was 16.40 (range 7 to 21) weeks. Six of the patients (60%) with distraction experienced pin tract infections that were treated with oral antibiotics. The reported mean preoperative categorical pain score in 7 patients (7 feet) was 8.2 (range 5 to 10), and the postoperative score was 0.83 (range 0 to 2; p = .001). Of the 6 patients (6 feet) who responded to the remaining portion of the survey, 4 (66.67%) were very satisfied with their results, and 2 (33.33%) were satisfied with their surgical result. None of the patients required additional surgical treatment during the mean 2.2 (range 1.2 to 3.3) years of follow-up. Hinged first metatarsophalangeal joint distraction with external fixation has been shown to be a viable treatment option for joint preservation for stage II and III hallux rigidus in the short term.

Motion versus fixed distraction of the joint in the treatment of ankle osteoarthritis: a prospective randomized controlled trial

BACKGROUND

Initial reports have shown the efficacy of fixed distraction for the treatment of ankle osteoarthritis. We hypothesized that allowing ankle motion during distraction would result in significant improvements in outcomes compared with distraction without ankle motion.

METHODS

We conducted a prospective randomized controlled trial comparing the outcomes for patients with advanced ankle osteoarthritis who were managed with anterior osteophyte removal and either (1) fixed ankle distraction or (2) ankle distraction permitting joint motion. Thirty-six patients were randomized to treatment with either fixed distraction or distraction with motion. The patients were followed for twenty-four months after frame removal. The Ankle Osteoarthritis Scale (AOS) was the main outcome variable.

RESULTS

Two years after frame removal, subjects in both groups showed significant improvement compared with the status before treatment (p < 0.02 for both groups). The motion-distraction group had significantly better AOS scores than the fixed-distraction group at twenty-six, fifty-two, and 104 weeks after frame removal (p < 0.01 at each time point). At 104 weeks, the motion-distraction group had an overall mean improvement of 56.6% in the AOS score, whereas the fixed-distraction group had a mean improvement of 22.9% (p < 0.01).

CONCLUSION

Distraction improved the patient-reported outcomes of treatment of ankle osteoarthritis. Adding ankle motion to distraction showed an early and sustained beneficial effect on outcome.

Quantification of the radiographic joint space width of the ankle

Quantification of joint space width of the ankle could provide information essential to evaluate the effects of potential disease-modifying agents and adverse effects of devices intended to ameliorate osteoarthritis elsewhere in the lower extremity. Current methods require proprietary software or have not been well validated; our purpose was to develop and assess the reliability of a digital joint space width quantification method using public access software. We studied 95 patients, asymptomatic in the ankles and without history of ankle trauma, but with symptomatic medial knee osteoarthritis, participating in an ongoing longitudinal trial. Weightbearing anteroposterior radiographs of the ankle and supine radiographs of the pelvis were assessed, and the narrowest medial and lateral tibiotalar joint space widths and hip joint space widths were measured using Image J software (US NIH, Bethesda, MD). Medial joint space widths were 2.56 +/- 0.50 and 2.55 +/- 0.48 mm, and lateral joint space widths were 2.45 +/- 0.55 and 2.44 +/- 0.52 mm, for right and left ankle, respectively. Coefficients of variation for repeat measurements by the same observer were 1.13% and 4.5%, and by different observers 7.30% and 7.27%, for medial and lateral joint space widths, respectively. Men had wider joint space widths than women when accounting for height. Joint space width of the ankle correlated with the joint space width of the hip and with height and weight, but not with age.

MRI evaluation of ankle distraction: a preliminary report

Ankle joint distraction has been shown to be a viable alternative to ankle arthrodesis or ankle replacement. The authors' approach to ankle joint preservation includes articulated ankle joint distraction, resection of blocking osteophytes, release of muscle and joint contractures, and realignment osseous ankle procedures. In a previous study that used this technique, 78% of patients maintained their ankle range of motion and had none to occasional moderate pain that could be managed generally with nonsteroid anti-inflammatory drugs alone. The rationale as to why joint distraction is successful is largely unknown. Therefore, the purpose of this study was to evaluate pre- and postoperative ankle MRI scans of patients who underwent hinged ankle joint distraction with external fixation.

Automatic quantification of joint space narrowing and erosions in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease that affects and potentially destroys the joints of the appendicular skeleton. The precise and reproducible quantification of the progression of joint space narrowing and the erosive bone destructions caused by RA is crucial during treatment and in imaging biomarkers in clinical trials. Current manual scoring methods exhibit high interreader variability, even after intensive training, and thus, impede the efficient monitoring of the disease. We propose a fully automatic quantitative assessment of the radiographic changes that result from RA, to increase the accuracy, reproducibility, and speed of image interpretation. Initial joint location estimates are obtained by local linear mappings based on texture features. Bone contours are delineated by active shape models comprised of statistical models of bone shape and local texture. These models are refined by snakes which increase the accuracy and allow for a fitting of pathological deviations from the training population. The method then measures joint space widths and detects erosions on the bone contour. Joint space widths are measured with a coefficient of variation of 2%-7% for repeated measurements and erosion detection exhibits an area under the receiver operating characteristic (ROC) curve of 0.89. Model landmarks serve as a reference system along the contour. These landmarks enable the definition of joint regions and more specific follow-up monitoring. The automatic quantification allows for a remote analysis, relevant for multicenter clinical trials, and reduces the workload of clinical experts since parts of the process can be managed by nonexpert personnel.

Distraction arthroplasty of the ankle--how far can you stretch the indications?

Ankle joint distraction has been shown to be a viable alternative to ankle arthrodesis or ankle replacement. The à la carte approach to ankle joint preservation (resection of blocking osteophytes, release of muscle/joint contractures, and realignment osseous ankle procedures) presented in this article as important for a successful outcome as is the hinged ankle joint distraction technique itself. The authors reviewed 32 patients who underwent this ankle joint distraction technique and found 78% of patients had maintained their ankle range of motion and have no pain to occasional moderate pain that can be managed generally with nonsteroidal anti-inflammatory drugs alone. Only one has required an ankle fusion, and only one has been converted to an ankle joint replacement. The longevity of these results and the higher percent of good or excellent results when compared with other studies suggest that combining adjunctive procedures and articulation with ankle distraction improves the results of this procedure.

Knee Images Digital Analysis (KIDA): a novel method to quantify individual radiographic features of knee osteoarthritis in detail

OBJECTIVE

Radiography is still the golden standard for imaging features of osteoarthritis (OA), such as joint space narrowing, subchondral sclerosis, and osteophyte formation. Objective assessment, however, remains difficult. The goal of the present study was to evaluate a novel digital method to analyse standard knee radiographs.

METHODS

Standardized radiographs of 20 healthy and 55 OA knees were taken in general practise according to the semi-flexed method by Buckland-Wright. Joint Space Width (JSW), osteophyte area, subchondral bone density, joint angle, and tibial eminence height were measured as continuous variables using newly developed Knee Images Digital Analysis (KIDA) software on a standard PC. Two observers evaluated the radiographs twice, each on two different occasions. The observers were blinded to the source of the radiographs and to their previous measurements. Statistical analysis to compare measurements within and between observers was performed according to Bland and Altman. Correlations between KIDA data and Kellgren & Lawrence (K&L) grade were calculated and data of healthy knees were compared to those of OA knees.

RESULTS

Intra- and inter-observer variations for measurement of JSW, subchondral bone density, osteophytes, tibial eminence, and joint angle were small. Significant correlations were found between KIDA parameters and K&L grade. Furthermore, significant differences were found between healthy and OA knees.

CONCLUSION

In addition to JSW measurement, objective evaluation of osteophyte formation and subchondral bone density is possible on standard radiographs. The measured differences between OA and healthy individuals suggest that KIDA allows detection of changes in time, although sensitivity to change has to be demonstrated in long-term follow-up studies.

Ankle joint distraction

Ankle joint distraction is a viable alternative to ankle arthrodesis or ankle replacement. A congruent, painful, mobile, and arthritic ankle joint that is treated with this technique can achieve good to excellent results. Attention to the principles (anterior osteophyte resection, equinus contracture release, and ankle joint realignment procedures) is as important for a successful outcome as the accurate application of the hinged ankle joint distraction technique itself.

Clinical benefit of joint distraction in the treatment of ankle osteoarthritis

Irrespective of underlying mechanisms, the structural changes after joint distraction and the efficacy during several years validate the concept of joint distraction in the treatment of osteoarthritis. Therefore, joint distraction in the case of severe ankle osteoarthritis at relatively young age may be a treatment of choice. In the light of increased aging, and the limited life span of an endoprosthesis, evaluation of joint distraction in the case of knee and hip osteoarthritis is justified.

Clinical benefit of joint distraction in the treatment of severe osteoarthritis of the ankle: proof of concept in an open prospective study and in a randomized controlled study

OBJECTIVE

Osteoarthritis (OA) is a degenerative, disabling joint disease that affects >10% of the adult population. No effective disease-modifying treatment is available. In the present study, we used joint distraction, a relatively new treatment in which mechanical contact between the articular surfaces is avoided while intraarticular intermittent fluid pressure is maintained, to treat patients with severe OA of the ankle.

METHODS

Patients with severe ankle OA (n = 57) who were being considered for joint fusion (arthrodesis) were treated with joint distraction in an open prospective study. In addition, a randomized trial was performed in 17 patients to determine whether joint distraction had a better outcome than debridement. A standardized evaluation protocol (physical examination, assessment of pain, mobility, and functional ability) was used, and changes in radiographic joint space width and subchondral sclerosis were measured. Thirty-eight patients in the open study have been followed up for >1 year, with up to 5 years of followup in 7 of them (mean +/- SD followup 2.8 +/- 0.3 years). Patients in the randomized study have been followed up for 1 year.

RESULTS

Significant clinical benefit was found in three-fourths of the 57 patients in the open prospective study. Most interestingly, the improvement increased over time. Radiographic evaluation showed increased joint space width and decreased subchondral sclerosis. Moreover, joint distraction showed significantly better results than debridement.

CONCLUSION

The clinical benefit of joint distraction in the treatment of severe OA is proof of the concept. Although the followup remains relatively short and effects over time remain unpredictable, our study creates possibilities for the treatment of severe OA in general. Considering the high prevalence of OA and the lack of a cure for it, joint distraction as a treatment of severe OA may have great medical, social, and economic impact.

Joint distraction as an alternative for the treatment of osteoarthritis

Irrespective of underlying mechanisms, the long-term efficacy of joint distraction in the treatment of severe ankle osteoarthritis at young age validates the concept of joint distraction in the treatment of osteoarthritis. Therefore, joint distraction in the case of severe ankle osteoarthritis may be a treatment of choice. This opens the possibility to study joint distraction as a treatment for other joints. Because knee osteoarthritis is much more common, it is a much greater social and economic problem. Beneficial effects of joint distraction in the case of ankle osteoarthritis, and specifically in the treatment of more common forms of osteoarthritis such as severe knee and hip osteoarthritis, may therefore have a great impact, especially in view of the increasing age of our population.