C. Niek van Dijk

The basic science of the subchondral bone.

In the past decades, considerable efforts have been made to propose experimental and clinical treatments for articular cartilage defects. Yet, the problem of cartilage defects extending deep in the underlying subchondral bone has not received adequate attention. A profound understanding of the basic anatomic aspects of this particular site, together with the pathophysiology of diseases affecting the subchondral bone is the key to develop targeted and effective therapeutic strategies to treat osteochondral defects. The subchondral bone consists of the subchondral bone plate and the subarticular spongiosa. It is separated by the cement line from the calcified zone of the articular cartilage. A variable anatomy is characteristic for the subchondral region, reflected in differences in thickness, density, and composition of the subchondral bone plate, contour of the tidemark and cement line, and the number and types of channels penetrating into the calcified cartilage. This review aims at providing insights into the anatomy, morphology, and pathology of the subchondral bone. Individual diseases affecting the subchondral bone, such as traumatic osteochondral defects, osteochondritis dissecans, osteonecrosis, and osteoarthritis are also discussed. A better knowledge of the basic science of the subchondral region, together with additional investigations in animal models and patients may translate into improved therapies for articular cartilage defects that arise from or extend into the subchondral bone.

A Prospective Study of Prognostic Factors Concerning the Outcome of Arthroscopic Surgery for Anterior Ankle Impingement

Sixty-two consecutive patients with painful limited dor siflexion of the ankle not responding to nonoperative treatment participated in a prospective study. All 42 men and 20 women (average age, 31 years) under went arthroscopic surgery. Preoperative radiographs were graded according to an osteoarthritic and an impingement classification. Standardized followup took place at 4 months and 1 and 2 years after surgery. Results showed that the degree of osteoarthritic changes is a better prognostic factor for the outcome of arthroscopic surgery for anterior ankle impingement than size and location of the spurs. The hypothesis is that osteophytes without joint space narrowing are not a manifestation of osteoarthritic changes but rather the result of local (micro)trauma. After 2 years, 73% of the patients experienced overall excellent or good results; 90% of those without joint space narrowing had good or excellent results, and 50% of those with joint space narrowing had good or excellent results. At the 2-year followup, the group without joint space narrowing showed significantly better scores in pain, swelling, ability to work, and engagement in sports. This study also revealed that patients with less than 2 years of ankle pain before surgery and spurs located anterome dially were more satisfied with the outcome than when longer periods of preoperative pain were involved and when spurs were located anterolaterally.

Terminology and classification of muscle injuries in sport: The Munich consensus statement

Objective To provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies. Methods Thirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientific definitions of muscle injuries as well as a new and comprehensive classification system. Results The response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub)total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type. Conclusions A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature. What are the new things Consensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries. Level of evidence Expert opinion, Level V.

Prospective study on diagnostic strategies in osteochondral lesions of the talus IS MRI SUPERIOR TO HELICAL CT

Our aim in this prospective study was to determine the best diagnostic method for discriminating between patients with and without osteochondral lesions of the talus, with special relevance to the value of MRI compared with the new technique of multidetector helical CT. We compared the diagnostic value of history, physical examination and standard radiography, a 4 cm heel-rise view, helical CT, MRI, and diagnostic arthroscopy for simultaneous detection or exclusion of osteochondral lesions of the talus. A consecutive series of 103 patients (104 ankles) with chronic ankle pain was included in this study. Of these, 29 with 35 osteochondral lesions were identified. Twenty-seven lesions were located in the talus. Our findings showed that helical CT, MRI and diagnostic arthroscopy were significantly better than history, physical examination and standard radiography for detecting or excluding an osteochondral lesion. Also, MRI and diagnostic arthroscopy performed better than a mortise view with a 4 cm heel-rise. We did not find a statistically significant difference between helical CT and MRI. Diagnostic arthroscopy did not perform better than helical CT and MRI for detecting or excluding an osteochondral lesion.

Osteochondral defects in the ankle: why painful?

Osteochondral defects of the ankle can either heal and remain asymptomatic or progress to deep ankle pain on weight bearing and formation of subchondral bone cysts. The development of a symptomatic OD depends on various factors, including the damage and insufficient repair of the subchondral bone plate. The ankle joint has a high congruency. During loading, compressed cartilage forces its water into the microfractured subchondral bone, leading to a localized high increased flow and pressure of fluid in the subchondral bone. This will result in local osteolysis and can explain the slow development of a subchondral cyst. The pain does not arise from the cartilage lesion, but is most probably caused by repetitive high fluid pressure during walking, which results in stimulation of the highly innervated subchondral bone underneath the cartilage defect. Understanding the natural history of osteochondral defects could lead to the development of strategies for preventing progressive joint damage.

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

AbstractOsteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity. Level of evidence IV.

Anatomy of the ankle ligaments: a pictorial essay

Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail.

Two and three-dimensional computed tomography for the classification and management of distal humeral fractures. Evaluation of reliability and diagnostic accuracy.

BACKGROUND Complex fractures of the distal part of the humerus can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional reconstructions of computed tomography scans improve the reliability and accuracy of fracture characterization, classification, and treatment decisions. METHODS Five independent observers evaluated thirty consecutive intra-articular fractures of the distal part of the humerus for the presence of five fracture characteristics: a fracture line in the coronal plane; articular comminution; metaphyseal comminution; the presence of separate, entirely articular fragments; and impaction of the articular surface. Fractures were also classified according to the AO/ASIF Comprehensive Classification of Fractures and the classification system of Mehne and Matta. Two rounds of evaluation were performed and then compared. Initially, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, two weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed. RESULTS Three-dimensional computed tomography improved both the intraobserver and the interobserver reliability of the AO classification system and the Mehne and Matta classification system. Three-dimensional computed tomography reconstructions also improved the intraobserver agreement for all fracture characteristics, from moderate (average kappa [kappa2D] = 0.554) to substantial agreement (kappa3D = 0.793). The addition of three-dimensional images had limited influence on the interobserver reliability and diagnostic characteristics (sensitivity, specificity, and accuracy) for the recognition of specific fracture characteristics. Three-dimensional computed tomography images improved intraobserver agreement (kappa2D = 0.62 compared with kappa3D = 0.75) but not interobserver agreement (kappa2D = 0.24 compared with kappa3D = 0.28) for treatment decisions. CONCLUSIONS Three-dimensional reconstructions improve the reliability, but not the accuracy, of fracture classification and characterization. The influence of three-dimensional computed tomography was much more notable for intraobserver comparisons than for interobserver comparisons, suggesting that different observers see different things in the scans-most likely a reflection of the training, knowledge, and experience of the observer with regard to these relatively uncommon and complex injuries.

Long-Term Outcome of Anatomical Reconstruction Versus Tenodesis for the Treatment of Chronic Anterolateral Instability of the Ankle Joint: A Multicenter Study

The long-term clinical outcome after anatomical reconstruction and tenodesis in the treatment of chronic anterolateral ankle instability was assessed in a retrospective multicentre study. The first group (AR) consisted of 25 patients (mean age at operation 22 yrs ± 5.7) who underwent anatomical reconstruction and the second group (TE) of 29 patients (mean age 23 yrs ± 6.6) who underwent tenodesis. For both groups, the mean follow-up period was 12.3 yrs (AR ± 2.5 yrs, TE ± 2.7 yrs). At physical examination, there were significantly more patients in the TE group (n = 18) with a positive anterior drawer sign as compared with the AR group (n = 7) (p = 0.02). Medially located degenerative changes in the ankle joint as seen on standard radiographs were seen more often in the TE group (n = 7) than in the AR group (n = 1) (p = 0.03). The mean talar tilt, 4.7° in the AR group vs 6.9° in the TE group, (p = 0.02) and anterior talar translation, 2.9 mm in the AR group vs 4.3 mm in the TE group, (p = 0.04) were significantly higher in the TE group at radiographic stress examination. According to the rating system developed by Good et al. (1975), significantly fewer patients in the TE group (n = 8) had an excellent result as compared with the AR group (n = 15) (p = 0.03) and more patients in the TE group (n = 9) had a fair or poor result (p = 0.04) as compared with the AR group (n = 2). We conclude that a tenodesis procedure does not restore the normal anatomy of the lateral ankle ligaments. When compared with anatomical reconstruction, a tenodesis leads to inferior results in terms of functional and mechanical stability, as well as overall satisfaction at long-term follow-up.

ARTHROSCOPY FOR PROBLEMS AFTER ANKLE FRACTURE

From 1990 to 1994 we undertook arthroscopy of the ankle on 34 consecutive patients with residual complaints following fracture. Two groups were compared prospectively. Group I comprised 18 patients with complaints which could be attributed clinically to anterior bony or soft-tissue impingement. In group II the complaints of the 16 patients were more diffuse and despite extensive investigation the definitive diagnosis was not clear before arthroscopy. At the time of the fracture, some osteophytes were already present in 41% of the patients. These were related to previous supination trauma and participation in soccer. Arthroscopic treatment consisted of removal of the anteriorly located osteophytes and/or scar tissue. After two years, group I showed a significantly better score for patient satisfaction (p = 0.02). There were good or excellent results in group I in 76% and group II in 43%. Patients with residual complaints after an ankle fracture and clinical signs of anterior impingement may benefit from arthroscopic surgery. The place for diagnostic ankle arthroscopy is limited.