Does Consulting an Occupational Medicine Specialist Decrease Time to Return to Work Among Total Knee Arthroplasty Patients? A 12-Month Prospective Multicenter Cohort Study.

PURPOSE: The aim of this study is to investigate whether total knee arthroplasty (TKA) patients who consulted an occupational medicine specialist (OMS) within 3 months after surgery, return to work (RTW) earlier than patients who did not consult an OMS. METHODS: A multi-center prospective cohort study was performed among working TKA patients, aged 18 to 65 years and intending to RTW. Time to RTW was analyzed using Kaplan Meier and Mann Whitney U (MWU), and multiple linear regression analysis was used to adjust for effect modification and confounding. RESULTS: One hundred and eighty-two (182) patients were included with a median age of 59 years [IQR 54-62], including 95 women (52%). Patients who consulted an OMS were less often self-employed but did not differ on other patient and work-related characteristics. TKA patients who consulted an OMS returned to work later than those who did not (median 78 versus 62 days, MWU p < 0.01). The effect of consulting an OMS on time to RTW was modified by patients' expectations in linear regression analysis (p = 0.05). A median decrease in time of 24 days was found in TKA patients with preoperative high expectations not consulting an OMS (p = 0.03), not in patients with low expectations. CONCLUSIONS: Consulting an OMS within 3 months after surgery did not result in a decrease in time to RTW in TKA patients. TKA patients with high expectations did RTW earlier without consulting an OMS. Intervention studies on how OMSs can positively influence a timely RTW, incorporating patients' preoperative expectations, are needed.

Anatomic stabilization techniques provide superior results in terms of functional outcome in patients suffering from chronic ankle instability compared to non-anatomic techniques.

PURPOSE: To determine the best surgical treatment for chronic ankle instability (CAI) a systematic review was performed to compare the functional outcomes between various surgical stabilization methods. METHODS: A systematic search was performed from 1950 up to April 2016 using PubMed, EMBASE, Medline and the Cochrane Library. Inclusion criteria were a minimum age of 18 years, persistent lateral ankle instability, treatment by some form of surgical stabilization, described functional outcome measures. Exclusion criteria were case reports, (systematic) reviews, articles not published in English, description of only acute instability or only conservative treatment, medial ankle instability and concomitant injuries, deformities or previous surgical treatment for ankle instability. After inclusion, studies were critically appraised using the Modified Coleman Methodology Score. RESULTS: The search resulted in a total of 19 articles, including 882 patients, which were included in this review. The Modified Coleman Methodology Score ranged from 30 to 73 points on a scale from 0 to 90 points. The AOFAS and Karlsson Score were the most commonly used patient-reported outcome measures to assess functional outcome after surgery. Anatomic repair showed the highest post-operative scores [AOFAS 93.8 (SD ± 2.7; n = 119); Karlsson 95.1 (SD ± 3.6, n = 121)], compared to anatomic reconstruction [AOFAS 90.2 (SD ± 10.9, n = 128); Karlsson 90.1 (SD ± 7.8, n = 35)] and tenodesis [AOFAS 86.5 (SD ± 12.0, n = 10); Karlsson 85.3 (SD ± 2.5, n = 39)]. Anatomic reconstruction showed the highest score increase after surgery (AOFAS 37.0 (SD ± 6.8, n = 128); Karlsson 51.6 (SD ± 5.5, n = 35) compared to anatomic repair [AOFAS 31.8 (SD ± 5.3, n = 119); Karlsson 40.9 (SD ± 2.9, n = 121)] and tenodesis [AOFAS 19.5 (SD ± 13.7, n = 10); Karlsson 29.4 (SD ± 6.3, n = 39)] (p < 0.005). CONCLUSION: Anatomic reconstruction and anatomic repair provide better functional outcome after surgical treatment of patients with CAI compared to tenodesis reconstruction. These results further discourage the use of tenodesis reconstruction and other non-anatomic surgical techniques. Future studies may be required to indicate potential value of tenodesis reconstruction when used as a salvage procedure. Not optimal, but the latter still provides an increase in functional outcome post-operatively. Anatomic reconstruction seems to give the best results, but may be more invasive than anatomic repair. This has to be kept in mind when choosing between reconstruction and repair in the treatment of CAI. LEVEL OF EVIDENCE: IV.

Predicted osteotomy planes are accurate when using patient-specific instrumentation for total knee arthroplasty in cadavers: a descriptive analysis.

PURPOSE: Malalignment of implants is a major source of failure during total knee arthroplasty. To achieve more accurate 3D planning and execution of the osteotomy cuts during surgery, the Signature (Biomet, Warsaw) patient-specific instrumentation (PSI) was used to produce pin guides for the positioning of the osteotomy blocks by means of computer-aided manufacture based on CT scan images. The research question of this study is: what is the transfer accuracy of osteotomy planes predicted by the Signature PSI system for preoperative 3D planning and intraoperative block-guided pin placement to perform total knee arthroplasty procedures? METHODS: The transfer accuracy achieved by using the Signature PSI system was evaluated by comparing the osteotomy planes predicted preoperatively with the osteotomy planes seen intraoperatively in human cadaveric legs. Outcomes were measured in terms of translational and rotational errors (varus, valgus, flexion, extension and axial rotation) for both tibia and femur osteotomies. RESULTS: Average translational errors between the osteotomy planes predicted using the Signature system and the actual osteotomy planes achieved was 0.8 mm (± 0.5 mm) for the tibia and 0.7 mm (± 4.0 mm) for the femur. Average rotational errors in relation to predicted and achieved osteotomy planes were 0.1° (± 1.2°) of varus and 0.4° (± 1.7°) of anterior slope (extension) for the tibia, and 2.8° (± 2.0°) of varus and 0.9° (± 2.7°) of flexion and 1.4° (± 2.2°) of external rotation for the femur. CONCLUSION: The similarity between osteotomy planes predicted using the Signature system and osteotomy planes actually achieved was excellent for the tibia although some discrepancies were seen for the femur. The use of 3D system techniques in TKA surgery can provide accurate intraoperative guidance, especially for patients with deformed bone, tailored to individual patients and ensure better placement of the implant.

Computer-assisted oblique single-cut rotation osteotomy to reduce a multidirectional tibia deformity: case report.

The correction of multiplanar deformity is challenging. We describe preoperative 3-D planning and treatment of a complex tibia malunion using an oblique single-cut rotation osteotomy to correct deformity parameters in the sagittal, coronal and transverse plane. At 5 years postoperatively, the patient ambulates without pain with a well-aligned leg.

Computed tomography analysis of osteochondral defects of the talus after arthroscopic debridement and microfracture.

PURPOSE: The primary surgical treatment of osteochondral defects (OCD) of the talus is arthroscopic debridement and microfracture. Healing of the subchondral bone is important because it affects cartilage repair and thus plays a role in pathogenesis of osteoarthritis. The purpose of this study was to evaluate the dimensional changes and bony healing of talar OCDs after arthroscopic debridement and microfracture. METHODS: Fifty-eight patients with a talar OCD were treated with arthroscopic debridement and microfracture. Computed tomography (CT) scans were obtained at baseline, 2 weeks postoperatively, and 1 year postoperatively. Three-dimensional changes and bony healing were analysed on CT scans. Additionally, clinical outcome was measured with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and numeric rating scales (NRS) for pain. RESULTS: Average OCD size increased significantly (p < 0.001) in all directions from 8.6 (SD 3.6) × 6.3 (SD 2.6) × 4.8 (SD 2.3) mm (anterior-posterior × medial-lateral × depth) preoperatively to 11.3 (SD 3.4) × 7.9 (SD 2.8) × 5.8 (SD 2.3) mm 2 weeks postoperatively. At 1-year follow-up, average defect size was 8.3 (SD 4.2) × 5.7 (SD 3.0) × 3.6 (SD 2.4) mm. Only average defect depth decreased significantly (p < 0.001) from preoperative to 1 year postoperative. Fourteen of the 58 OCDs were well healed. No significant differences in the AOFAS and NRS-pain were found between the well and poorly healed OCDs. CONCLUSION: Arthroscopic debridement and microfracture of a talar OCD leads to an increased defect size on the direct postoperative CT scan but restores at 1-year follow-up. Only fourteen of the 58 OCDs were filled up completely, but no differences were found between the clinical outcomes and defect healing at 1-year follow-up. LEVEL OF EVIDENCE: IV.

Evaluation of a CT-based technique to measure the transfer accuracy of a virtually planned osteotomy.

Accurate transfer of a preoperatively planned osteotomy plane to the bone is of significance for corrective surgery, tumor resection, implant positioning and evaluation of new osteotomy techniques. Methods for comparing a preoperatively planned osteotomy plane with a surgical cut exist but the accuracy of these techniques are either limited or unknown. This paper proposes and evaluates a CT-based technique that enables comparing virtual with actual osteotomy planes. The methodological accuracy and reproducibility of the technique is evaluated using CT-derived volume data of a cadaver limb, which serves to plan TKA osteotomies in 3-D space and to simulate perfect osteotomies not hampered by surgical errors. The methodological variability of the technique is further investigated with repeated CT scans after actual osteotomy surgery of the same cadaver specimen. Plane displacement (derr) and angulation errors in the sagittal and coronal plane (ßerr, γerr) are measured with high accuracy and reproducibility (derr=-0.11±0.06mm; ßerr=0.08±0.04°, γerr=-0.03±0.03°). The proposed method for evaluating an osteotomy plane position and orientation has a high intrinsic accuracy and reproducibility. The method can be of great value for measuring the transfer accuracy of new techniques for positioning and orienting a surgical cut in 3-D space.

Accuracy of a computer-assisted planning and placement system for anatomical femoral tunnel positioning in anterior cruciate ligament reconstruction.

BACKGROUND: Femoral tunnel positioning is a difficult, but important factor in successful anterior cruciate ligament (ACL) reconstruction. Computer navigation can improve the anatomical planning procedure besides the tunnel placement procedure. METHODS: The accuracy of the computer-assisted femoral tunnel positioning method for anatomical double bundle ACL-reconstruction with a three-dimensional template was determined with respect to both aspects for AM and PL bundles in 12 cadaveric knees. RESULTS: The accuracy of the total tunnel positioning procedure was 2.7 mm (AM) and 3.2 mm (PL). These values consisted of the accuracies for planning (AM:2.9 mm; PL:3.2 mm) and for placement (about 0.4 mm). The template showed a systematic bias for the PL-position. CONCLUSIONS: The computer-assisted templating method showed high accuracy for tunnel placement and has promising capacity for application in anatomical tunnel planning. Improvement of the template will result in an accurate and robust navigation system for femoral tunnel positioning in ACL-reconstruction.

Morphological analysis of subchondral talar cysts on microCT.

PURPOSE: Osteochondral talar defects often present in conjunction with subchondral bone cysts. The exact aetiology of these cysts is unknown. Recently was shown in a computational bone model that pressurized fluid and osteocyte death could lead to cyst growth, through mechanoregulated bone adaptation. However, a difference in cyst morphology was present between the mechanisms. The purpose of this study was to evaluate and compare the cyst morphology of human cadaveric tali by using microCT with the morphological simulation results previously reported. MATERIALS AND METHODS: Sixty-six fresh-frozen human cadaveric tali were screened in a regular CT for subchondral bone cysts, radiologically defined as unexpected rounded radiolucent area. Subsequently, the tali with a cyst were scanned in a microCT. The shape of the cysts, the presence of an opening through the subchondral bone plate, and the bone volume fraction around and next to the cyst were analysed. RESULTS: In total, six tali were found to have a single cyst. Four cysts had an irregular shape, and two cysts were rounded. A clear opening from the cyst through the subchondral bone plate was found (diameter 0.5-1.7 mm) in four cysts. The bone volume fraction was higher (p = 0.025) around the cyst then next to the cyst. CONCLUSIONS: The morphological findings that we found are only compatible with the previously reported simulation results of cyst growth in response to pressurized fluid, or pressurized fluid in combination with osteocyte death. It is therefore most likely that pressurized fluid plays a role in the pathoaetiology of cyst growth. A better understanding of cyst growth may improve treatment and prevent further cyst formation.

Computer-assisted anatomically placed double-bundle ACL reconstruction: an in vitro experiment with different tension angles for the AM and the PL graft.

Anterior cruciate ligament reconstruction techniques are evolving with innovations like double-bundle (DB) grafts and computer assistance. The current DB techniques do not appear to make the clinical difference yet. Insight in various techniques may lead to better results. In this study, the anterior laxity of a DB reconstruction with an anteromedial (AM) graft fixated in 90° of flexion and a posterolateral (PL) graft fixated in 20° and computer-assisted anatomically placed femoral attachments was compared to normal values and single-bundle grafts. In 8 fresh-frozen human cadaveric knees, the anterior laxity was tested from 0° to 90° flexion, with a 100 Newton (N) anterior tibial load in joints with (1) intact ACL, (2) torn ACL, (3) single-bundle (SB) graft tensed with 15 N in 20°, (4) anatomic AM graft tensed with 15 N in 90°, (5) anatomic PL graft tensed with 15 N in 20°, and (6) anatomic DB graft (4+5). All reconstructions caused a posterior position of the tibia. Relative to the normal anterior laxity, the single-bundle techniques showed significantly increased laxities: The SB technique in 0° (+1.1 mm) and 15° (+1.7 mm); The AM reconstructions in 45° (+1.6 mm) and 90° (+1.5 mm); The PL reconstructions in all angles (from +1.4 to +2.3 mm), except in 0°. The anatomic DB technique showed no significantly increased laxities and restored normal laxity in all angles.

Computer-assisted and patient-specific 3-D planning and evaluation of a single-cut rotational osteotomy for complex long-bone deformities.

Malunion after long bone fracture results in an incorrect position of the distal bone segment. This misalignment may lead to reduced function of the limb, early osteoarthritis and chronic pain. An established treatment option is a corrective osteotomy. For complex malunions, a single-cut rotational osteotomy is sometimes preferred in cases of angular deformity in three dimensions. However, planning and performing this type of osteotomy is relatively complex. This report describes a computer-assisted method for 3-D planning and realizing a single-cut rotational osteotomy with a patient-specific cutting guide for orienting the osteotomy and an angled jig for adjusting the rotation angle. The accuracy and reproducibility of the method is evaluated experimentally using plastic bones. In addition, complex rotational deformities are simulated by a computer to investigate the relation between deformity and correction parameters. The computed relation between deformity and correction parameters enables the surgeon to judge the feasibility of a single-cut rotational osteotomy. This appears possible for deformities combining axial misalignment with sufficient axial rotation. The proposed 3-D method of preoperative planning and transfer with a patient-specific cutting guide and angled jig renders the osteotomy procedure easily applicable, accurate, reproducible, and is a good alternative for complex and expensive navigation systems.

The role of the fibula in varus and valgus deformity of the tibia: a biomechanical study.

It has been suggested that a supramalleolar osteotomy can return the load distribution in the ankle joint to normal. However, due to the lack of biomechanical data, this supposition remains empirical. The purpose of this biomechanical study was to determine the effect of simulated supramalleolar varus and valgus alignment on the tibiotalar joint pressure, in order to investigate its relationship to the development of osteoarthritis. We also wished to establish the rationale behind corrective osteotomy of the distal tibia. We studied 17 cadaveric lower legs and quantified the changes in pressure and force transfer across the tibiotalar joint for various degrees of varus and valgus deformity in the supramalleolar area. We assumed that a supramalleolar osteotomy which created a varus deformity of the ankle would result in medial overload of the tibiotalar joint. Similarly, we thought that creating a supramalleolar valgus deformity would cause a shift in contact towards the lateral side of the tibiotalar joint. The opposite was observed. The restricting role of the fibula was revealed by carrying out an osteotomy directly above the syndesmosis. In end-stage ankle osteoarthritis with either a valgus or varus deformity, the role of the fibula should be appreciated and its effect addressed where appropriate.

The role of pressurized fluid in subchondral bone cyst growth.

Pressurized fluid has been proposed to play an important role in subchondral bone cyst development. However, the exact mechanism remains speculative. We used an established computational mechanoregulated bone adaptation model to investigate two hypotheses: 1) pressurized fluid causes cyst growth through altered bone tissue loading conditions, 2) pressurized fluid causes cyst growth through osteocyte death. In a 2D finite element model of bone microarchitecture, a marrow cavity was filled with fluid to resemble a cyst. Subsequently, the fluid was pressurized, or osteocyte death was simulated, or both. Rather than increasing the load, which was the prevailing hypothesis, pressurized fluid decreased the load on the surrounding bone, thereby leading to net bone resorption and growth of the cavity. In this scenario an irregularly shaped cavity developed which became rounded and obtained a rim of sclerotic bone after removal of the pressurized fluid. This indicates that cyst development may occur in a step-wise manner. In the simulations of osteocyte death, cavity growth also occurred, and the cavity immediately obtained a rounded shape and a sclerotic rim. Combining both mechanisms increased the growth rate of the cavity. In conclusion, both stress-shielding by pressurized fluid, and osteocyte death may cause cyst growth. In vivo observations of pressurized cyst fluid, dead osteocytes, and different appearances of cysts similar to our simulation results support the idea that both mechanisms can simultaneously play a role in the development and growth of subchondral bone cysts.

The influence of foot geometry on the calcaneal osteotomy angle based on two-dimensional static force analyses.

BACKGROUND: Malalignment of the hindfoot can be corrected with a calcaneal osteotomy (CO). A well-selected osteotomy angle in the sagittal plane will reduce the shear force in the osteotomy plane while walking. The purpose was to determine the presence of a relationship between the foot geometry and loading of the calcaneus, which influences the choice of the preferred CO angle. METHODS: A static free body force analysis was made of the posterior calcaneal fragment in the second half of the stance phase to determine the main loads: the plantar apeunorosis (PA) and Achilles tendon (AT). The third load is on the osteotomy surface which should be oriented such that the shear component of the force is zero. The force direction of the PA and AT was measured on 58 MRIs of the foot, and the force ratio between both structures was taken from the literature. In addition the PA-to-AT force ratio was estimated for different foot geometries to identify the relationship. RESULTS: Based on the wish to minimize the shear force during walking, a mean CO angle was determined to be 33° (SD8) relative to the foot sole. In pes planus foot geometry, the angle should be higher than the mean. In pes cavus foot geometry, the angle should be smaller. CONCLUSION: Foot geometry, in particular the relative foot heights is a determinant for the individual angle in performing the sliding calcaneal osteotomy. It is recommended to take into account the foot geometry (arch) when deciding on the CO angle for hindfoot correction.

Performance of arthroscopic irrigation systems assessed with automatic blood detection.

PURPOSE: During arthroscopies, bleeding episodes occur as a result of tissue damage. Irrigation systems assist in minimizing these disturbances. The performance of three arthroscopic irrigation systems in clearing bleeding episodes was evaluated objectively. METHODS: One surgeon performed 99 shoulder arthroscopies using three irrigation systems: gravity infusion, single roller, and double roller pump. The three irrigation systems groups were matched postoperatively for type of surgery-acromioplasty, SLAP, release, rotator cuff repair and capsule repair, and operation duration. The recorded arthroscopies were analyzed for the presence of bleeding episodes with a special computer program that automatically detects the tinctures of red-colored blood. A least 20% of an arthroscopic image had to be covered with blood to qualify as bleeding episode. RESULTS: The median (min-max) presence of bleeding episodes as a percentage of the operation time was 6.6% (0.0-43.6%) for gravity infusion, 3.7% (0.2-46.4%) for the single roller, and 3.3% (0.0-19.3%) for the double roller pump, respectively. The large variation could be attributed to the occurrence of arterial bleeding episodes during some procedures. No significant differences were found between the irrigation systems. For a subgroup including acromioplasties and releases, significant differences were found in favor of both roller pumps (P < 0.05). CONCLUSIONS: Overall, the roller pumps did not outperform gravity infusion. However, from the results, high-risk procedures for bleeding episodes were identified (acromioplasty and release of a frozen shoulder) that can benefit from the use of roller pumps. A clear view is essential to perform an arthroscopic procedure safely and efficiently.

Development of a femoral template for computer-assisted tunnel placement in anatomical double-bundle ACL reconstruction.

Femoral graft placement is an important factor in the success of anterior cruciate ligament (ACL) reconstruction. In addition to improving the accuracy of femoral tunnel placement, Computer Assisted Surgery (CAS) can be used to determine the anatomic location. This is achieved by using a 3D femoral template which indicates the position of the anatomical ACL center based on endoscopically measurable landmarks. This study describes the development and application of this method. The template is generated through statistical shape analysis of the ACL insertion, with respect to the anteromedial (AM) and posterolateral (PL) bundles. The ligament insertion data, together with the osteocartilage edge on the lateral notch, were mapped onto a cylinder fitted to the intercondylar notch surface (n = 33). Anatomic variation, in terms of standard variation of the positions of the ligament centers in the template, was within 2.2 mm. The resulting template was programmed in a computer-assisted navigation system for ACL replacement and its accuracy and precision were determined on 31 femora. It was found that with the navigation system the AM and PL tunnels could be positioned with an accuracy of 2.5 mm relative to the anatomic insertion centers; the precision was 2.4 mm. This system consists of a template that can easily be implemented in 3D computer navigation software. Requiring no preoperative images and planning, the system provides adequate accuracy and precision to position the entrance of the femoral tunnels for anatomical single- or double-bundle ACL reconstruction.

Difference in balance measures between patients with chronic ankle instability and patients after an acute ankle inversion trauma.

Neuromuscular control of the ankle is disturbed in patients with chronic ankle instability due to an initial ankle inversion trauma. Static balance is assumed to be a measure for this disturbance. Functional (ankle) scores are another way to evaluate ankle impairment. The hypothesis was that there is a difference in static balance measures between small groups of healthy subjects, patients after an acute ankle inversion trauma and patients with chronic ankle instability and that static balance measures correlate well with functional scores. Static balance in healthy subjects (N = 15), patients after a primary ankle inversion injury (N = 14) and patients with chronic ankle instability (N = 23) was tested with a single leg test on a force plate (Postural Sway test) and on a compliant floor (Simple Balance test). Functional impairment was evaluated with the Karlsson, AOFAS and SF-36 (ankle) scores. There was a statistically significant and clinically relevant difference in functional (ankle) scores, but not a statistically significant difference in balance measures between the groups. Balance measures did not correlate to the functional scores. It was concluded that, despite a clinically relevant difference in functional outcome measures between the groups, static balance measures do not appear to be useful for clinical application in the individual patient.

Quantitative detection of cartilage surfaces and ligament geometry of the wrist using an imaging cryomicrotome system.

Biomechanical models may aid in improving diagnosis and treatment of wrist joint disorders. As input, geometrical information is required for model development. Previous studies acquired some elements of the average wrist joint geometry. However, there is a close geometric functional match between articulating surfaces and ligament geometry. Therefore, biomechanical models need to be fed with the geometric data of individual joints. This study is aimed at acquiring geometric data of cartilage surfaces and ligaments from individual wrist joints by using a cryomicrotome imaging system and the evaluation of inter- and intra-observer variability of the data. The 3D geometry of 30 cartilage surfaces and 15 ligaments in three cadaver wrists was manually detected and quantitatively reconstructed. The inter- and intra-observer variability of the cartilage surface detection was 0.14 and 0.19 mm, respectively. For the position of the radius attachment of the dorsal radiocarpal ligament (DRC), the observer variations were 0.12 and 0.65 mm, for intra-/inter-observer, respectively. For the DRC attachment on the triquetrum, the observer variations were 0.22 and 1.19 mm. Anatomic reconstruction from 3D cryomicrotome images offer a method to obtain unique geometry data of the entire wrist joint for modeling purposes.

Clinical evaluation of a dynamic test for lateral ankle ligament laxity.

The dynamic anterior ankle tester (DAAT) has shown a good reliability in testing anterior talar translation in earlier studies. The goal of the present study was first to evaluate the reliability of the DAAT in a clinical setting and second to analyze its ability to detect increased ligament laxity. In 39 patients with unilateral chronic lateral ankle instability, the anterior talar translation of the affected and non-affected side was measured pre and postoperatively using the DAAT, Telos stress radiographs, and the manual anterior drawer test. In contrast to both other tests, the DAAT was not able to accurately detect increased ligament laxity preoperatively or decreased laxity of the affected ankle postoperatively. The DAAT showed a low sensitivity to change (the difference between the mean pre and postoperative value) and a low reliability compared to both other tests. There were no correlations between the three tests. In conclusion, the DAAT showed a low reliability in effectively testing lateral ankle ligament laxity in a clinical setting. This is in contrast to earlier evaluations.

In-vivo three-dimensional carpal bone kinematics during flexion-extension and radio-ulnar deviation of the wrist: Dynamic motion versus step-wise static wrist positions.

An in-vivo approach to the measurement of three-dimensional motion patterns of carpal bones in the wrist may have future diagnostic applications, particularly for ligament injuries of the wrist. Static methods to measure carpal kinematics in-vivo only provide an approximation of the true kinematics of the carpal bones. This study is aimed at finding the difference between dynamically and statically acquired carpal kinematics. For eight healthy subjects, static and a dynamic measurements of the carpal kinematics were performed for a flexion-extension and a radio-ulnar deviation movement. Dynamic scans were acquired by using a four-dimensional X-ray imaging system during an imposed cyclic motion. To assess static kinematics of the wrists, three-dimensional rotational X-ray scans were acquired during step-wise flexion-extension and radio-ulnar deviation. The helical axis rotations and the rotation components. i.e. flexion-extension, radio-ulnar deviation and pro-supination were the primary parameters. Linear mixed model statistical analysis was used to determine the significance of the difference between the dynamically and statically acquired rotations of the carpal bones. Small and in most cases negligible differences were observed between the dynamic motion and the step-wise static motion of the carpal bones. The conclusion is that in the case of individuals without any pathology of the wrist, carpal kinematics can be studied either dynamically or statically. Further research is required to investigate the dynamic in-vivo carpal kinematics in patients with dynamic wrist problems.

Interventions for treating chronic ankle instability.

BACKGROUND: Chronic lateral ankle instability occurs in 10% to 20% of people after an acute ankle sprain. The initial form of treatment is conservative but if this fails and ligament laxity is present, surgical intervention is considered. OBJECTIVES: To compare different treatments, both conservative and surgical, for chronic lateral ankle instability. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialized Register (to July 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 3), and MEDLINE (1966 to April 2006), EMBASE (1980 to April 2006), CINAHL (1982 to April 2006) and reference lists of articles. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials of interventions for chronic lateral ankle instability were included. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed methodological quality and extracted data. Where appropriate, results of comparable studies were pooled. MAIN RESULTS: Seven randomised trials were included and divided into three groups: surgical interventions; rehabilitation programs after surgical interventions; and conservative interventions. None of the studies were methodologically flawless. Only one study described an adequate randomisation procedure. Only two studies, both about rehabilitation programs after surgery, had a moderate risk of bias; all other studies had a high risk of bias. Due to clinical and methodological diversity, extensive pooling of the data was not possible. Surgical interventions (four studies): one study showed more complications after the Chrisman-Snook procedure compared to an anatomical reconstruction, whereas another study showed greater mean talar tilt after an anatomical reconstruction. Subjective instability and hindfoot inversion was greater after a dynamic than after a static tenodesis in a third study. The fourth study showed that the operating time for anatomical reconstructions was shorter for the reinsertion technique than for the imbrication method. Rehabilitation after surgical interventions (two studies): both studies provided evidence that early functional mobilization leads to an earlier return to work and sports than immobilisation. Conservative interventions: the only study in this group showed better proprioception and functional outcome with the bi-directional than with the uni-directional pedal technique on a cyclo-ergometer. AUTHORS' CONCLUSIONS: In view of the low quality methodology of almost all the studies, this review does not provide sufficient evidence to support any specific surgical or conservative intervention for chronic ankle instability. However, after surgical reconstruction, early functional rehabilitation was shown to be superior to six weeks immobilisation regarding time to return to work and sports.