Revision Risk of Unipolar and Bipolar Hemiarthroplasties in the Dutch Arthroplasty Register.

BACKGROUND: Hemiarthroplasty (HA) for hip fractures can be performed with a unipolar or bipolar head. We describe the use of unipolar and bipolar HA after a hip fracture in the Netherlands and determined revision rates and risk factors. METHODS: All HAs for an acute hip fracture registered in the Dutch Arthroplasty Register (LROI) during 2007 to 2021 were included; 44,127(88%) unipolar and 6,013(12%) bipolar HAs. Competing risk survival analyses were performed with revision for any reason as the endpoint. Multivariable Cox regression analyses were performed adjusting for patient and surgery-related factors. RESULTS: The 1-year, 5-year, and 10-year revision rates were comparable for unipolar and bipolar HA. Cox regression analysis showed a hazard ratio of 1.2 (95% confidence interval (CI) 1.0 to 1.4)) after adjustment for confounders for bipolar heads. In cases of a cemented stem, the 1-year cumulative incidence of revision was lower (1.5% (CI 1.4 to 1.7%) compared to uncemented stems (2.4% (CI 2.1 to 2.7%); uncemented stems showed higher risks for revision after adjustment compared to cemented stems (hazard ratio 1.4 (CI 1.2 to 1.5)). The anterior, antero-lateral, and straight-lateral approach showed lower risk for revision compared to the postero-lateral approach. CONCLUSION: The revision rate for bipolar HA and unipolar HA was comparable. However, after adjustment for potential confounders the risk for revision showed an estimated 20% increased revision risk for bipolar heads, although not statistically significant. For both head types, the risk for revision was significantly higher when an uncemented stem was chosen or the postero-lateral approach was used.

Comparable mortality but higher revision rate after uncemented compared with cemented total hip arthroplasties in patients 80 years and older: report of 43,053 cases of the Dutch Arthroplasty Register.

Background and purpose - Mortality and revision risks are important issues during shared decision-making for total hip arthroplasty (THA) especially in elderly patients. We examined mortality and revision rates as well as associated patient and prosthesis factors in primary THA for osteoarthritis (OA) in patients ≥ 80 years in the Netherlands. Patients and methods - We included all primary THAs for OA in patients ≥ 80 years in the period 2007-2019. Patient mortality and prosthesis revision rates were calculated using Kaplan-Meier survival analyses. Risk factors for patient mortality and prosthesis revision were analyzed using multivariable Cox regression analysis adjusted for age, sex, ASA class, fixation method, head size, and approach. Results - Mortality was 0.2% at 7 days, 0.4% at 30 days, 2.7% at 1 year, and 20% at 5 years. Mortality was higher in males and higher ASA class, but did not differ between fixation methods. The 1-year revision rate was 1.6% (95% CI 1.5-1.7) and 2.6% (CI 2.5-2.7) after 5 years. Multivariable Cox regression analysis showed a higher risk of revision for uncemented (hazard ratio [HR] 1.6; CI 1.4-1.8) and reverse hybrid THAs (HR 2.9; CI 2.1-3.8) compared with cemented THAs. Periprosthetic fracture was the most frequently registered reason for revision in uncemented THAs. Interpretation - Mortality is comparable but revision rate is higher after uncemented compared with cemented THA in patients 80 years and older, indicating that cemented THA might be a safer option in this patient group.

Low revision rate of dual mobility cups after arthroplasty for acute hip fractures: report of 11,857 hip fractures in the Dutch Arthroplasty Register (2007-2019).

Background and purpose - Dislocation is one of the most frequent reasons for cup revision after total hip arthroplasty (THA) for an acute fracture. A dual mobility cup (DMC) might reduce this risk. We determined the cup revision rate after THA for an acute fracture according to type of cup.Patients and methods - All THAs for an acute fracture registered in the Dutch Arthroplasty Register (LROI) during 2007-2019 were included (n = 11,857). Type of cup was divided into DMC and unipolar cup (UC). Competing risk analyses were performed with cup revision for any reason as endpoint. Multivariable Cox regression analyses with outcome cup revision were performed adjusted for sex, age, ASA class, and surgical approach, stratified for UC THA with femoral head size of 32 mm and 22-28 mm.Results - A DMC was used in 1,122 (9%) hips. The overall 5-year cup revision rate for any reason after THA for acute fracture was 1.9% (95% CI 1.6-2.2). Cup revision for dislocation within 5 years was performed in 1 of 6 DMC THAs versus 108 of 185 (58%) UC THAs. Univariable Cox regression analyses showed no statistically significant difference in cup revision rate between DMC and UC (HR = 0.8; CI 0.4-1.5). Multivariable Cox regression analyses showed lower risk of cup revision in DMC THA (n = 1,122) compared with UC THA with 22-28 mm femoral head size (n = 2,727) (HR = 0.4; CI 0.2-0.8).Interpretation - The 5-year cup cumulative incidence of revision after THA for acute fracture was comparable for DMC and UC THA. However, DMC THA had a lower risk of cup revision than UC THA with 22-28 mm femoral head.

Lower 5-year cup re-revision rate for dual mobility cups compared with unipolar cups: report of 15,922 cup revision cases in the Dutch Arthroplasty Register (2007-2016).

Background and purpose - During revision hip arthroplasty the dual mobility cup (DMC) is widely used to prevent dislocation despite limited knowledge of implant longevity. We determined the 5-year cup re-revision rates of DMC compared with unipolar cups (UC) following cup revisions in the Netherlands. Patients and methods - 17,870 cup revisions (index cup revision) were registered in the Dutch Arthroplasty Register during 2007-2016. Due to missing data 1,948 revisions were excluded and the remaining 15,922 were divided into 2 groups: DMC (n = 4,637) and UC (n = 11,285). Crude competing risk and multivariable Cox regression analysis were performed with cup re-revision for any reason as endpoint. Adjustments were made for known patient characteristics. Results - The use of DMC (in index cup revisions) increased from 23% (373/1,606) in 2010 to 47% (791/1,685) in 2016. Patients in the index DMC cup revision group generally had a higher ASA score and the cups were mainly cemented (89%). The main indication for index cup revision was loosening. In the DMC group dislocation was the 2nd main indication for revision. Overall 5-year cup re-revision rate was 3.5% (95% CI 3.0-4.2) for DMC and 6.7% (CI 6.3-7.2) for UC. Cup re-revision for dislocation was more frequent in the UC group compared with the DMC group (32% [261/814] versus 18% [28/152]). Stratified analyses for cup fixation showed a higher cup re-revision rate for UC in both the cemented and uncemented group. Multivariable regression analyses showed a lower risk for cup re-revision for DMC compared with UC (HR 0.5 [CI 0.4-0.6]). Interpretation - The use of DMC in cup revisions increased over time with differences in patient characteristics. The 5-year cup re-revision rates for DMC were statistically significantly lower than for UC.

Dual mobility cups in primary total hip arthroplasties: trend over time in use, patient characteristics, and mid-term revision in 3,038 cases in the Dutch Arthroplasty Register (2007-2016).

Background and purpose - We noticed an increased use of dual mobility cups (DMC) in primary total hip arthroplasty (THA) despite limited knowledge of implant longevity. Therefore, we determined the trend over time and mid-term cup revision rates of DMC compared with unipolar cups (UC) in primary THA. Patients and methods - All primary THA registered in the Dutch Arthroplasty Register (LROI) during 2007-2016 were included (n = 215,953) and divided into 2 groups - DMC THA (n = 3,038) and UC THA (n = 212,915). Crude competing risk and multivariable Cox regression analyses were performed with cup revision for any reason as primary endpoint. Adjustments were made for sex, age, diagnosis at primary THA, previous operation, ASA score, type of fixation, surgical approach, and femoral head size. Results - The proportion of primary DMC THA increased from 0.8% (n = 184) in 2010 to 2.6% (n = 740) in 2016. Patients who underwent DMC THA more often had a previous operation on the affected hip, a higher ASA score, and the diagnosis acute fracture or late posttraumatic status compared with the UC THA group. Overall 5-year cup revision rate was 1.5% (95% CI 1.0-2.3) for DMC and 1.4% (CI 1.3-1.4) for UC THA. Stratified analyses for patient characteristics showed no differences in cup revision rates between the 2 groups. Multivariable regression analyses showed no statistically significantly increased risk for revision for DMC THA (HR 0.9 [0.6-1.2]). Interpretation - The use of primary DMC THA increased with differences in patient characteristics. The 5-year cup revision rates for DMC THA and UC THA were comparable.

Higher mid-term revision rates of posterior stabilized compared with cruciate retaining total knee arthroplasties: 133,841 cemented arthroplasties for osteoarthritis in the Netherlands in 2007-2016.

Background and purpose - The preference for a cruciate retaining (CR) or posterior stabilized (PS) TKA (total knee arthroplasty) system varies greatly between Dutch hospitals, independent of patient characteristics. We examined mid-term revision rates for men and women of different age categories. Patients and methods - We included all 133,841 cemented fixed-bearing primary CR or PS TKAs for osteoarthritis reported in the Dutch Arthroplasty Register (LROI) in 2007-2016. Revision procedures were defined as minor when only insert and/or patella were revised and as major when fixed components (tibia and femur) were revised or removed. 8-year all-cause revision rates of CR and PS TKAs were calculated using competing-risk analyses. Cox-regression analyses were performed, adjusted for age at surgery, sex, ASA -score, and previous operations. Results - PS TKAs were 1.5 (95% CI 1.4-1.6) times more likely to be revised within 8 years of the primary procedure, compared with CR TKAs. When stratified for sex and age category, 8-year revision rate of PS TKAs in men <60 years was 13% (CI 11-15), compared to 7.2% (CI 6.1-8.5) of CR TKAs. Less prominent differences were found in older men and women. For men <60 years differences were found for minor (CR 1.8% (CI 1.4-2.5); PS 3.7% (CI 3.0-4.7)) and major revisions (CR 4.2% (CI 3.3-5.3); PS 7.0% (CI 5.6-8.7)). Interpretation - Patients who received a cemented fixed-bearing primary PS TKA for osteoarthritis are more likely to undergo either a minor or a major revision within 8 years. This is especially prominent for younger men.

Gastrocnemius recession: A cadaveric study of surgical safety and effectiveness.

Background and purpose - Many methods of gastrocnemius lengthening have been described, with different surgical challenges, outcomes, and risks to the sural nerve. Our aims were (1) to locate the gastrocnemius muscular-tendinous junction in relation to the mid-length of the fibula (from here on designated the mid-fibula), (2) to compare the dorsiflexion achieved with dorsal recession or ventral recession, and (3) to determine the risk of injury to the sural nerve during gastrocnemius recession. Methods - In 10 pairs of fresh-frozen adult cadaveric lower extremities transected above the knee, we measured dorsiflexion, performed dorsal or ventral gastrocnemius recession at the mid-fibula, and then measured the increase in dorsiflexion and fasciotomy gap. We noted the course of the sural nerve and whether the gastrocnemius muscle provided it with enough muscular coverage to protect it during recession. Results - Dorsal and ventral recession produced statistically (p < 0.05) and clinically significant mean increases in dorsiflexion with extended knee from 12° to 19°, but they were not statistically significantly different from each other in this measure or in fasciotomy gap size. At the mid-fibula, the sural nerve coursed superficially between both heads of the gastrocnemius muscle in 14 of 20 specimens. Sufficient gastrocnemius muscle coverage to protect the sural nerve was provided by the medial head in 18 of 20 specimens and by the lateral head in only 5 of 20 specimens. Interpretation - A ventral gastrocnemius recession proximal to the mid-fibula level poses less risk to the sural nerve than a recession at the mid-fibula. This procedure provides adequate lengthening (1-3 cm) and increased dorsiflexion (compared with baseline), with less risk to the sural nerve than is incurred with recession at the mid-fibular reference line.

Non-surgical care in patients with hip or knee osteoarthritis is modestly consistent with a stepped care strategy after its implementation.

OBJECTIVE: To improve the management of hip or knee osteoarthritis (OA), a stepped care strategy (SCS) has been developed that presents the optimal sequence for care in three steps. This study evaluates the extent to which clinical practice is consistent with the strategy after implementation and identifies determinants of SCS-consistent care. DESIGN: A 2-year observational prospective cohort study. SETTING: General practices in the region of Nijmegen in the Netherlands. PARTICIPANTS: Three hundred and thirteen patients with hip or knee OA and their general practitioner (GP). INTERVENTIONS: Multifaceted interventions were developed to implement the strategy. MAIN OUTCOME MEASURES: Consistency between clinical practice and the strategy was examined regarding three aspects of care: (i) timing of radiological assessment, (ii) sequence of non-surgical treatment options and (iii) making follow-up appointments. RESULTS: Out of the 212 patients who reported to have had an X-ray, 92 (44%) received it in line with the SCS. The sequence of treatment was inconsistent with the SCS in 58% of the patients, which was mainly caused by the underuse of lifestyle advice and dietary therapy. In 57% of the consultations, the patient reported to have been advised to make a follow-up appointment. No determinants that influenced all three aspects of care were identified. CONCLUSIONS: Consistency with the SCS was found in about half of the patients for each of the three aspects of care. Health care can be further optimized by encouraging GP s to use X-rays more appropriately and to make more use of lifestyle advice, dietary therapy and follow-up appointments.

Agreement of general practitioners with the guideline-based stepped-care strategy for patients with osteoarthritis of the hip or knee: a cross-sectional study.

BACKGROUND: To improve the management of hip or knee osteoarthritis (OA), a multidisciplinary guideline-based stepped-care strategy (SCS) with recommendations regarding the appropriate non-surgical treatment modalities and optimal sequence for care has been developed. Implementation of this SCS in the general practice may be hampered by the negative attitude of general practitioners (GPs) towards the strategy. In order to develop a tailored implementation plan, we assessed the GPs' views regarding specific recommendations in the SCS and their working procedures with regard to OA. METHODS: A survey was conducted among a random sample of Dutch GPs. Questions included the GP's demographical characteristics and the practice setting as well as how the management of OA was organized and whether the GPs supported the SCS recommendations. In particular, we assessed GP's views regarding the effectiveness of 14 recommended and non-recommended treatment modalities. Furthermore, we calculated their agreement with 7 statements based on the SCS recommendations regarding the sequence for care. With a linear regression model, we identified factors that seemed to influence the GPs' agreement with the SCS recommendations. RESULTS: Four hundred fifty-six GPs (37%) aged 30-65 years, of whom 278 males (61%), responded. Seven of the 11 recommended modalities (i.e. oral Non-Steroidal Anti-Inflammatory Drugs, physical therapy, glucocorticoid intra-articular injections, education, lifestyle advice, acetaminophen, and tramadol) were considered effective by the majority of the GPs (varying between 95-60%). The mean agreement score, based on a 5-point scale, with the recommendations regarding the sequence for care was 2.8 (SD = 0.5). Ten percent of the variance in GPs' agreement could be explained by the GPs' attitudes regarding the effectiveness of the recommended and non-recommended non-surgical treatment modalities and the type of practice. CONCLUSION: In general, GPs support the recommendations in the SCS. Therefore, we expect that their attitudes will not impede a successful implementation in general practice. Our results provide several starting points on which to focus implementation activities for specific SCS recommendations; those related to the prescription of pain medication and the use of X-rays. We could not identify factors that contribute substantially to GPs' attitudes regarding the SCS recommendations regarding the sequence for care.

The use of a dual-mobility concept in total hip arthroplasty patients with spastic disorders: no dislocations in a series of ten cases at midterm follow-up.

INTRODUCTION: Total hip arthroplasty (THA) is one of the treatment options in patients with cerebral palsy (CP) with painful osteoarthritis of the hip. However, the risk of dislocation of the prosthesis is higher in patients with CP when compared with physically normal patients. In this retrospective study of ten consecutive cases, we hypothesized that the use of a dual-mobility cup could reduce this risk of dislocation combined with good functional results. MATERIALS AND METHODS: From January 2008 until October 2010, eight patients (ten hips) with CP who consecutively received a THA using a dual-mobility cup were identified. At the time of surgery, the average age of the patient group was 54 years (range 43-61). Latest follow-up took place after on average 39 months (range 22-56 months). All patients or their caregivers were interviewed by telephone. They were asked if dislocation of the prosthesis had occurred. To evaluate quality of life and health in general, patients completed the SF-36 questionnaire. RESULTS: None of the prostheses had dislocated at the latest follow-up. Reoperation was needed in one patient after a periprosthetic fracture. Radiologic evaluation showed a mean cup inclination of 46 (range 27-58). On average, the quality of life of patients in this study was found to be limited in particular on the domains of physical health and functioning, while a fair to good score was measured at the six other different domains. CONCLUSION: The use of a dual-mobility cup in THA in patients with CP can lead to favourable results with respect to dislocation and clinical outcome.

The prognosis of ankle fractures: a systematic review.

The aim of this study was to update the scientific evidence for ankle fracture prognosis by addressing radiographic osteoarthritis, time course and prognostic factors. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included if they were randomized controlled trials, controlled trials or observational studies, including case series and case-control studies investigating radiologically confirmed osteoarthritis in adults with a classified ankle fracture, treated with or without surgery, with a minimum follow-up of 1 year. Also included were studies examining prognostic factors predicting radiologically confirmed osteoarthritis. Tibial plafond and talus fractures were excluded. Thirty-four studies were included examining 3447 patients. Extracted data included study type, inclusion and exclusion criteria, age, number of patients, number of fractures according to the author-reported classification method, radiological osteoarthritis, follow-up period, prognostic factors, and treatment. Severe heterogeneity was visible in the analyses (I2 > 90%), reflecting clinical heterogeneity possibly arising from the presence of osteoarthritis at baseline, the classifications used for the fractures and for osteoarthritis. The incidence of osteoarthritis was 25% (95% CI: 18-32) and 34% (95% CI: 23-45) for more severe fractures with involvement of the posterior malleolus. The severity of the trauma, as reflected by the fracture classification, was the most important prognostic factor for the development of radiographic osteoarthritis, but there is also a risk with simpler injuries. The period within which osteoarthritis develops or becomes symptomatic with an indication for treatment could not be specified.

Chronic instability of the anterior tibiofibular syndesmosis of the ankle. Arthroscopic findings and results of anatomical reconstruction.

BACKGROUND: The arthroscopic findings in patients with chronic anterior syndesmotic instability that need reconstructive surgery have never been described extensively. METHODS: In 12 patients the clinical suspicion of chronic instability of the syndesmosis was confirmed during arthroscopy of the ankle. All findings during the arthroscopy were scored. Anatomical reconstruction of the anterior tibiofibular syndesmosis was performed in all patients. The AOFAS score was assessed to evaluate the result of the reconstruction. At an average of 43 months after the reconstruction all patients were seen for follow-up. RESULTS: The syndesmosis being easily accessible for the 3 mm transverse end of probe which could be rotated around its longitudinal axis in all cases during arthroscopy of the ankle joint, confirmed the diagnosis. Cartilage damage was seen in 8 ankles, of which in 7 patients the damage was situated at the medial side of the ankle joint. The intraarticular part of anterior tibiofibular ligament was visibly damaged in 5 patients. Synovitis was seen in all but one ankle joint. After surgical reconstruction the AOFAS score improved from an average of 72 pre-operatively to 92 post-operatively. CONCLUSIONS: To confirm the clinical suspicion, the final diagnosis of chronic instability of the anterior syndesmosis can be made during arthroscopy of the ankle. Cartilage damage to the medial side of the tibiotalar joint is often seen and might be the result of syndesmotic instability. Good results are achieved by anatomic reconstruction of the anterior syndesmosis, and all patients in this study would undergo the surgery again if necessary.

Foot function after fusion of the first metatarsophalangeal joint.

BACKGROUND: We measured with a validated score the operative outcome in patients without concomitant foot surgery who underwent fusion of the first metatarsophalangeal (MTP) joint for hallux rigidus (HR) and hallux valgus (HV). We also examined whether there is a correlation between foot function and hallux position to try to formulate an optimum fusion angle. MATERIALS AND METHODS: Between 2002 and 2005, a consecutive series of 62 patients underwent crossed screw fusion of the first MTP joint (27 HR and 35 HV) without concomitant surgery of the same or contralateral foot or had previous surgery of the same foot. Foot function was measured by the Dutch Foot Function Index (FFI) pre- and postoperatively. Hallux valgus and dorsiflexion angles were measured on standing radiographs before operation and at followup. RESULTS: Postoperatively the median hallux valgus angle was 14 (range, -2 to 33) degrees and the median dorsiflexion angle was 23 (range, 7 to 45) degrees. The median FFI score improved from 38 (range, 0 to 80) to 8 (range, 0 to 59) (p < 0.001). The FFI score was not different between the HV and HR groups. There was no correlation between postoperative foot function, dorsiflexion angles and hallux valgus angles. CONCLUSION: Fusion of the first MTP joint in HR and HV results in improved function according to the validated FFI. There was no significant correlation between foot function and hallux position. This could be due to the fact that the desired position of the hallux was most often achieved.

Suture-button versus screw fixation in a syndesmosis rupture model: a biomechanical comparison.

BACKGROUND: Flexible suture-button devices are used to stabilize the distal tibiofibular joint after syndesmotic rupture, but little is known about how they affect fibular motion during cyclic physiological loading. This study examined how much fibular motion occurs during cyclic loading of ankles repaired with suture-buttons or screws relative to one with intact ligaments. MATERIALS AND METHODS: Ten pairs of cadaveric legs with intact ligaments were tested in axial compression (750 N), external rotational torque (7.5 Nm), and a combination thereof. Fibular rotation and translation in the sagittal and frontal planes were measured with linear variable displacement transducers. Then we sectioned the anterior tibiofibular, posterior tibiofibular, deltoid, and interosseous ligaments. Ankles were repaired with suture-buttons or a 3.5-mm screw through four-cortices. The ankles were tested for 10,000 cycles using the same loading protocol. Surviving ankles were brought to failure by increasing external rotation (1 degree/sec). Data from the linear variable differential transducers were used to calculate fibular motion at 100, 1,000, 5,000, and 10,000 cycles. RESULTS: There was no significant difference in the effect of the suture-button or screw for translation in the sagittal or coronal plane or for rotation about the fibular axis. The screw repair had a significantly greater (p = 0.02) failure torque (median, 26.5 Nm; inner quartile range, 25.7 to 35.2 Nm) than did the suture-button repair (median, 23.6 Nm; inner quartile range, 16.5 to 25.6 Nm). CONCLUSION: The fibular motion that occurs during cyclic loading appears to be similar for the suture-button and syndesmotic screw. Motion in both constructs was similar, but neither restored native ankle motion. CLINICAL RELEVANCE: It appears the suture-button behaves similarly to the syndesmotic screw in the syndesmotic rupture injury model tested. Clinical trials are needed to determine how the device performs in vivo.

Biomechanical comparison of the interosseous tibiofibular ligament and the anterior tibiofibular ligament.

BACKGROUND: The mechanical importance of the interosseous tibiofibular ligament of the ankle is unclear. The purpose of the current study was to compare the stiffness and strength of the interosseous tibiofibular ligament to that of the anterior tibiofibular ligament. METHODS: Twelve pairs of ankles were obtained from the Maryland State Anatomy Board. All soft tissue was removed except for the interosseous tibiofibular ligament in one ankle of each pair and the anterior tibiofibular ligament in the contralateral ankle. The assignment of which ligament would be excised in the right or left ankle of each pair was random. The specimens were potted as bone-ligament-bone preparations and mounted in a servohydraulic testing machine so that the ligament's long axis was coincident with the actuator. Specimens were elongated at 0.5 mm/s until rupture. Failure load and failure site were recorded, and stiffness was calculated. Stiffness and failure loads were compared with a paired t-test. Significance was set at p < 0.05. RESULTS: The interosseous ligament was significantly stiffer (234 +/- 122 N/mm) than the anterior tibiofibular ligament (162 +/- 64 N/mm). The mean failure load of the interosseous tibiofibular ligament (822 +/- 298 N) was significantly greater than that of the anterior tibiofibular ligament (625 +/- 255 N). CONCLUSIONS: The interosseous tibiofibular ligament is stiffer and stronger than the anterior tibiofibular ligament. CLINICAL RELEVANCE. The current study suggests that the interosseous ligament plays an important role in the stability of the ankle, and its status should be part of the diagnostic evaluation in syndesmotic instability.

[Unexplained pain in the ankle and foot. Consider transient osteoporosis]. / Onbegrepen pijn van de enkel en voet. Denk aan voorbijgaande osteoporose.

Transient osteoporosis is an increasingly recognized condition that causes severe pain in weight-bearing joints and is characterized by otherwise unexplained bone-marrow oedema on MRI. We present two patients, a 40-year-old man and a 60-year-old woman, with longstanding severe pain in the foot and ankle. Both had invalidating pain with only mild swelling of the foot or ankle. Laboratory investigation was unremarkable, and conventional X-ray showed osteopenia of the bones involved. In both cases, consecutive MRIs showed migrating bone marrow oedema. The patients were treated with analgesics, immobilization of the body parts concerned and an intravenous bisphosphonate.

A biomechanical evaluation of clinical stress tests for syndesmotic ankle instability.

Displacement transducers were placed across the anterior and posterior tibiofibular ligaments of 17 fresh cadaver (78.4 +/- 6.7 years old at death) lower extremities. Displacements induced by various clinical tests (squeeze, fibula translation, Cotton, external rotation, and anterior drawer) were measured with the ankle ligaments intact and after sequential sectioning of the anterior tibiofibular ligament, anterior deltoid ligament, and posterior tibiofibular ligament. None of the syndesmotic stress tests could distinguish which ligaments were sectioned. Furthermore, the small displacements measured during the stress tests (with the exception of the external rotation test) suggest it is unlikely that the displacement induced in injured syndesmoses can be clinically differentiated from normal syndesmoses. Therefore, pain, rather than increased displacement, should be considered the outcome measure of these tests.

A biomechanical evaluation of the tibiofibular and tibiotalar ligaments of the ankle.

The purpose of this ex vivo biomechanical study was to determine the strength and stiffness of the anterior and posterior syndesmotic tibiofibular ligaments and the posterior tibiotalar component of the deltoid ligament. Injuries to these ligaments are a prevalent clinical problem, yet little is known about their mechanical behavior. Ten fresh-frozen cadaver lower extremities (average age at death, 72 +/- 8 years) were harvested. The anterior and posterior tibiofibular ligaments and the posterior tibiotalar component of the deltoid were isolated and prepared as bone-ligament-bone complexes for tensile testing to determine strength, stiffness, and mode of failure. The posterior tibiofibular ligament exhibited greater strength, but not significantly so (p < .05), than the anterior tibiofibular ligament and the posterior tibiotalar component of the deltoid ligament. There were no significant differences in stiffness between the three ligaments tested. The dominant mode of failure for the anterior tibiofibular ligament was ligament substance rupture, primarily near its fibular insertion, whereas the failure modes of the posterior tibiofibular ligament were evenly split between substance ruptures and fibular avulsions. The posterior tibiotalar component of the deltoid ligament ruptured most often near the talar insertion. The tibiofibular ligaments showed greater strength than the lateral collateral and deltoid ligaments, as mentioned in literature. The greater strength of the tibiofibular ligaments relative to the lateral collateral and deltoid ligaments suggests that these ligaments play an important role in ankle constraint.