Knee rotation during a weightbearing activity: influence of turning.

Kinematic studies, in which mobile- and fixed-bearing total knee arthroplasty (TKA) were compared, showed controversial results with respect to axial femorotibial rotation. However, all studies focused only on straight ahead tasks, which may underestimate possible differences in freedom of rotation. The purpose of this study was to investigate the influence of turning on normal axial knee rotation. If large differences across tasks were to be found, this would support the use of this task in the evaluation of in-vivo TKA kinematics. In 15 healthy persons, crossover and sidestep turns were added to a standardized chair rise. Three-dimensional knee angles were recorded using an optoelectronic motion analysis system, and a noninvasive epicondylar frame was developed to track the femur. Compared to knee rotation during the straight ahead task, average peak tibial internal rotation increased during a crossover turn (p<0.001), as did peak external tibia rotation during a sidestep turn (p<0.001). The combined range of axial rotation for both turning tasks together was 20.9 degrees , versus 13.5 degrees for the straight ahead task (p<0.001). The turning maneuvers in this study induced a large range of axial knee rotation, so they could be important in studies comparing freedom of rotation in mobile- and fixed-bearing TKA.

[A missed unstable cervical vertebra fracture in a patient with ankylosing spondylitis]. / Een niet-herkende instabiele cervicale wervelfractuur bij een patient met de ziekte van Bechterew.

A 53-year-old man with a 13-year history ofankylosing spondylitis presented to the emergency clinic of another hospital because of neck pain after a fall from a low stepladder. The patient was put at ease and discharged after physical examination and X-ray of the cervical spine revealed nothing out of the ordinary. Because his neck pain persisted, the patient contacted his rheumatologist. New cervical X-rays revealed fractures of the body and articular process of CVI and CVII. The patient was referred to our hospital for orthopaedic treatment. The fractures healed during 2.5 months' treatment with halotraction and a halovest. All patients with ankylosing spondylitis with neck pain after trauma have an unstable cervical fracture until proven otherwise. Cervical fractures should be excluded in all cases and other diagnostic tools (CT-scan or MRI) must be used whenever necessary.

Use of the Souter-Strathclyde total elbow prosthesis in patients who have rheumatoid arthritis.

Thirty-three patients had thirty-four consecutive primary arthroplasties, with use of the Souter-Strathclyde cemented unconstrained prosthesis, for severe rheumatoid arthritis of the elbow. The minimum duration of follow-up for inclusion in the study was two years. Three patients died. Four arthroplasties were revised: three, because of irreducible dislocation immediately after the operation and one, because of loosening without infection. One prosthesis was removed because of a late deep infection. In most of the remaining twenty-five patients (twenty-six arthroplasties), who had an average duration of follow-up of four years (range, two to eight years), pain was markedly less or had resolved completely, and the function of the elbow was greatly improved.

Posterolateral dislocation of the elbow joint. Relationship to medial instability.

BACKGROUND: Dislocation of the elbow joint is the second most common dislocation in the upper extremity, dislocation of the shoulder being the most common. It has been reported that uncomplicated dislocation of the elbow joint may be associated with a decreased range of motion, degenerative changes in the elbow joint, ectopic calcification, or neurological deficits. As the medial collateral ligament complex can be completely disrupted during dislocation, we evaluated the association between the long-term results of treatment of simple posterolateral dislocation of the elbow and the presence of persistent medial or valgus elbow instability. METHODS: Fifty patients who had a mean age of thirty-three years (range, eighteen to fifty-eight years) had closed reduction of a posterolateral dislocation of the elbow without associated fractures. The extremity was immobilized in an above-the-elbow plaster cast for three weeks. After a mean duration of follow-up of nine years (range, six to thirteen years), forty-one patients were evaluated with an interview, a physical examination, and radiographs made while a valgus load was applied to the elbow. RESULTS: The average score according to the system of The Hospital for Special Surgery was 91 points (range, 49 to 100 points), and thirty-one patients described their elbow function as good or excellent. Twenty-four patients had evidence of medial instability on radiographs made while a valgus load was applied to the elbow. Twenty-one patients had signs of degeneration of the joint, and twenty-five patients had ectopic ossification. Magnetic resonance imaging combined with arthrography was performed for the first twenty patients; eight had evidence of rupture of the medial collateral ligament, seven had generalized degenerative changes of the cartilage, and four had a chondral defect of the capitellum. (The study could not be completed for the remaining patient.) Medial instability on radiographs was correlated with signs of degeneration (p = 0.001), ectopic ossification (p = 0.01), a worse score according to the system of The Hospital for Special Surgery (p = 0.002), and persistent pain (p = 0.04). CONCLUSIONS: Posterolateral dislocation of the elbow joint can lead to persistent valgus instability that is associated with a worse overall clinical and radiographic result.

The treatment of recurrent dislocation of the peroneal tendons.

Ten cases of post-traumatic recurrent dislocation of the peroneal tendons were operated on between 1974 and 1982. In all cases the disturbed superior peroneal retinaculum was reconstructed by transposition of the calcaneofibular ligament to the lateral side of the peroneal tendons. The calcaneal insertion of the calcaneofibular ligament was mobilised with a small bone block and reinserted in its bed after the transposition. After an average follow-up of four years all the results were satisfactory.

An experimental study of the failure modes of the Gamma Locking Nail and AO Dynamic Hip Screw under static loading: a cadaveric study.

The sliding compression screw is widely regarded as the optimum treatment for intertrochanteric fractures of the femur, allowing bone fragments to impact until a bony support has been established across the fracture site. This study carried out biomechanical, cadaveric tests to establish the influence of direct static loading situations on the modes of failure of the Gamma Nail compared with the Dynamic Hip Screw (DHS). Clinical studies report DHS failures of lag screws cutting-out, bending of the lag screws and cortical screws pulling out causing plate loosening. Gamma Nail failures include lag screw cut-out or fractures of the femoral shaft around the distal locking screws or nail tip. In this study each failure mode has been isolated, to establish the loads to failure under various fracture configurations. The biomechanical results indicated that the intramedullary Gamma Locking Nail can be recommended over a standard DHS in cases of subtrochanteric fracture or conditions of very poor bone quality.

[Thrombosis prevention in orthopaedic surgery: clinical practice in the Netherlands in 2002]. / Tromboseprofylaxe in de orthopedische chirurgie: de klinische praktijk in Nederland anno 2002.

OBJECTIVE: Establish the use of thromboprophylaxis in orthopaedic surgery both during and after the hospital admission. DESIGN: Cross-sectional study. METHOD: In April 2002, a letter was sent to all orthopaedic surgeons in the Netherlands announcing that at every hospital with a Department of Orthopaedic Surgery, an orthopaedic surgeon would be approached for a telephone survey. They were phoned in the months April-June 2002. This study included hospitals where major orthopaedic surgery (e.g. the insertion of hip or knee prostheses and hip fracture surgery) took place (n = 124) as well as clinics that only performed day treatments (n = 5). RESULTS: For major orthopaedic operations, 91% of the hospitals used low molecular weight heparin (LMWH) during the admission period: 36% as monotherapy and 55% in combination with coumarin derivates. In 85% of cases the use of LMWH was started preoperatively. Coumarin derivates were used as a monotherapy in 9% of the hospitals. In 37% of the hospitals the use of NSAIDs was continued, particularly in patients with rheumatoid arthritis. In 94% of the hospitals, the use of acetylsalicylic acid was always stopped. In 97% of the hospitals prophylaxis was given after discharge in the form of LMWH (37% of the cases) or coumarin derivates (63% of the cases). The use of thromboprophylaxis with respect to arthroscopies and plaster immobilisation was variable.

Patient acceptable symptom states after totalhip or knee replacement at mid-term follow-up: Thresholds of the Oxford hip and knee scores.

OBJECTIVES: To define Patient Acceptable Symptom State (PASS) thresholds for the Oxford hip score (OHS) and Oxford knee score (OKS) at mid-term follow-up. METHODS: In a prospective multicentre cohort study, OHS and OKS were collected at a mean follow-up of three years (1.5 to 6.0), combined with a numeric rating scale (NRS) for satisfaction and an external validation question assessing the patient's willingness to undergo surgery again. A total of 550 patients underwent total hip replacement (THR) and 367 underwent total knee replacement (TKR). RESULTS: Receiver operating characteristic (ROC) curves identified a PASS threshold of 42 for the OHS after THR and 37 for the OKS after TKR. THR patients with an OHS ≥ 42 and TKR patients with an OKS ≥ 37 had a higher NRS for satisfaction and a greater likelihood of being willing to undergo surgery again. CONCLUSIONS: PASS thresholds appear larger at mid-term follow-up than at six months after surgery. With- out external validation, we would advise against using these PASS thresholds as absolute thresholds in defining whether or not a patient has attained an acceptable symptom state after THR or TKR. Cite this article: Bone Joint Res 2014;3:7-13.

Hip and knee replacement patients prefer pen-and-paper questionnaires: Implications for future patient-reported outcome measure studies.

OBJECTIVES: Electronic forms of data collection have gained interest in recent years. In orthopaedics, little is known about patient preference regarding pen-and-paper or electronic questionnaires. We aimed to determine whether patients undergoing total hip (THR) or total knee replacement (TKR) prefer pen-and-paper or electronic questionnaires and to identify variables that predict preference for electronic questionnaires. METHODS: We asked patients who participated in a multi-centre cohort study investigating improvement in health-related quality of life (HRQoL) after THR and TKR using pen-and-paper questionnaires, which mode of questionnaire they preferred. Patient age, gender, highest completed level of schooling, body mass index (BMI), comorbidities, indication for joint replacement and pre-operative HRQoL were compared between the groups preferring different modes of questionnaire. We then performed logistic regression analyses to investigate which variables independently predicted preference of electronic questionnaires. RESULTS: A total of 565 THR patients and 387 TKR patients completed the preference question. Of the THR patients, 81.8% (95% confidence interval (CI) 78.4 to 84.7) preferred pen-and-paper questionnaires to electronic questionnaires, as did 86.8% (95% CI 83.1 to 89.8) of TKR patients. Younger age, male gender, higher completed level of schooling and higher BMI independently predicted preference of electronic questionnaires in THR patients. Younger age and higher completed level of schooling independently predicted preference of electronic questionnaires in TKR patients. CONCLUSIONS: The majority of THR and TKR patients prefer pen-and-paper questionnaires. Patients who preferred electronic questionnaires differed from patients who preferred pen-and-paper questionnaires. Restricting the mode of patient-reported outcome measures to electronic questionnaires might introduce selection bias. Cite this article: Bone Joint Res 2013;2:238-44.

The Femoral Epicondylar Frame to track femoral rotation in optoelectronic gait analysis.

Relative movement of skin markers to underlying bone limits a valid interpretation of axial femorotibial rotation in noninvasive optoelectronic gait analysis. A distal femoral clamp is a practical solution for thigh marker placement, however, existing devices are still susceptible to measurement errors at increased angles of knee flexion. We developed the Femoral Epicondylar Frame (FEF), which should result in less femoral rotational measurement error due to its anatomic fitting and controlled pressure adjustment. Seven subjects with a total knee replacement in situ, mean age 71 years, mean body mass index 28, were equipped with the frame mounted with a set of tantalum markers. Fluoroscopic data was collected during a step-up motion. A three-dimensional model fitting technique was used to compare the in vivo position and orientation of the frame and the femoral prosthesis component of the prosthesis. The frame rotational measurement error appeared to be linearly dependent on the knee flexion angle. When considering knee flexion angles lower than 40° of flexion, the highest measurement error was 3.3° on average, with an absolute extreme of 6.2°. It is concluded that the accuracy of the FEF is sufficient to evaluate axial knee rotation with optoelectronic gait analysis at group level in clinical studies.

Failure of femoral head fixation: a cadaveric analysis of lag screw cut-out with the gamma locking nail and AO dynamic hip screw.

The most commonly reported failure mode of sliding hip screws in published literature is cut-out of the lag screw. This study investigates the resistance to failure of the femoral head, with lag screws used in two types of sliding hip screws, the gamma locking nail (Howmedica) and the dynamic hip screw (DHS) (Synthes). The investigation consisted of biomechanical tests under static loading conditions on 12 pairs of cadaveric femoral heads, to establish the failure loads due to screw cut-out for the two implant lag screws. The gamma nail appeared to reduce the tendency to cut-out in the osteoporotic bone (soft) associated with elderly patients in whom these devices are commonly used (p < 0.05). In high density bone (hard) the gamma lag screw also appeared to be stronger, because the DHS showed a tendency to bend. The larger diameter of the gamma nail lag screw resists bending and appears to reduce the risk of cut-out compared with the DHS.