Predictive value of metacarpophalangeal stabilization tests for simulated ulnar nerve lesion measured by a sensor glove.

STUDY DESIGN: A within-subject research design was used in this study. The difference of the range of motion (ROM) with and without ulnar nerve block was analyzed. INTRODUCTION: For the clinical evaluation of the functional effects of ulnar nerve palsy at the hand the relevance of clinical tests is in discussion. PURPOSE OF THE STUDY: The aim of the study was to evaluate the predictive value of 2 clinical tests for a simulated ulnar nerve lesion by motion analysis with a sensor glove. METHODS: In 28 healthy subjects, dynamic measurements of the finger joints were performed by a sensor glove with and without ulnar nerve block at the wrist. In the 0° metacarpophalangeal (MCP) stabilization test, the subjects were asked to stabilize the MCP joints actively in 0° while moving the interphalangeal joints, whereas at the 90° MCP stabilization test, the subjects stabilized the MCP joints actively in the 90° position. RESULTS: In the 0° MCP stabilization test, no remarkable changes of the ROM were found at the MCP joints; at the proximal interphalangeal joints 2-5, the ROM decreased with ulnar nerve block, significantly at the index, middle, and ring fingers (P < .05). In the 90° MCP stabilization test, the average ROM of the MCP joints 2-5 significantly increased with ulnar nerve block (P < .05), whereas at the PIP joints, the average ROM decreased (P < .05). DISCUSSION: The 90° MCP stabilization test had a high predictive value for the discrimination between healthy subjects and subjects with a simulated peripheral ulnar nerve lesion. CONCLUSIONS: The results could be relevant for the determination of the functional effect of ulnar nerve palsy and the quantification of clawing in hand rehabilitation. LEVEL OF EVIDENCE: II.

Quantification of hand function by power grip and pinch strength force measurements in ulnar nerve lesion simulated by ulnar nerve block.

INTRODUCTION: In the assessment of hand and upper limb function, grip strength is of the major importance. The measurement by dynamometers has been established. PURPOSE OF THE STUDY: In this study, the effect of a simulated ulnar nerve lesion on different grip force measurements was evaluated. METHODS: In 25 healthy volunteers, grip force measurement was done by the JAMAR dynamometer (Fabrication Enterprises Inc, Irvington, NY) for power grip and by a pinch strength dynamometer for tip pinch strength, tripod grip, and key pinch strength. STUDY DESIGN: A within-subject research design was used in this prospective study. Each subject served as the control by preinjection measurements of grip and pinch strength. Subsequent measurements after ulnar nerve block were used to examine within-subject change. RESULTS: In power grip, there was a significant reduction of maximum grip force of 26.9% with ulnar nerve block compared with grip force without block (P < .0001). Larger reductions in pinch strength were observed with block: 57.5% in tip pinch strength (P < .0001), 61.0% in tripod grip (P < .0001), and 58.3% in key pinch strength (P < .0001). DISCUSSION: The effect of the distal ulnar nerve block on grip and pinch force could be confirmed. However, the assessment of other dimensions of hand strength as tip pinch, tripod pinch and key pinch had more relevance in demonstrating hand strength changes resulting from an distal ulnar nerve lesion. CONCLUSIONS: The measurement of tip pinch, tripod grip and key pinch can improve the follow-up in hand rehabilitation. LEVEL OF EVIDENCE: II.

Quantification of weakness caused by distal median nerve lesion by dynamometry.

INTRODUCTION: In the assessment of hand and upper limb function, grip strength is of major importance. Use of the JAMAR dynamometer has been an accepted test of grip strength and routinely part of the physical examination. PURPOSE OF THE STUDY: The aim of this study was to determine by means of a median nerve block simulating a patient group if the measurement of different types of grip force can improve the quantification of impairment of the hand beyond the sole power grip measurements. METHODS: In 29 healthy volunteers, grip force measurement was done by the JAMAR dynamometer for power grip and by a pinch grip dynamometer for pincer grip, precision grip, pinch grip, and palmar abduction. At the power grip, the force of digit 2-5 was measured separately by a sensor glove. For each measurement, 3 trials were recorded subsequently. STUDY DESIGN: A within-subject research design was used in this prospective study. Each subject served as the control by preinjection measurements of grip and pinch strength. Subsequent measurements after median nerve block were used to examine within-subject change. RESULTS: In power grip, there was no significant reduction of maximum grip force with median nerve block compared with grip force without block. By measuring the finger forces by a sensor glove, a reduction of force at the individual fingers was found compared with the setting with no block, although significant only at the middle finger (P < .017). With median nerve block, average grip force decreased significantly 20% in pincer grip (P < .021), 29.5% in pinch grip (P < .002), 39.5% in precision grip (P < .001), and 70.7% in palmar abduction (P < .013). CONCLUSIONS: These experiments suggest a minor role of the measurement of the power grip force in the diagnostics of distal median nerve block with the dynamometer, which could not be substantially improved by the digit forces and the force distribution of the individual fingers. The assessment of other grip forms, such as pincer grasp, precision grip, pinch grip, and especially palmar abduction, leads to a relevant improvement in the diagnostics of distal median nerve lesion. LEVEL OF EVIDENCE: II.

The effect of a combined thoracic and soft-tissue trauma on blood flow and tissue formation in fracture healing in rats.

INTRODUCTION: Previously, it was found that fracture healing is impaired by blunt chest trauma and an additional soft-tissue trauma. The mechanisms leading to this disturbance are largely unknown. Here, we investigated the effect of thoracic and soft-tissue trauma on blood flow of the injured lower leg and on tissue differentiation and callus formation during fracture healing. MATERIALS AND METHODS: Male Wistar rats received either a mid-shaft fracture of the tibia alone (group A), an additional chest trauma (group B), or additional chest and soft-tissue traumas (group C). Peripheral blood flow was determined by Laser Doppler Flowmetry before and after the injury, and on observation days 1, 3, 7, 14, and 28. Quantitative histological analysis was performed to assess callus size and composition. RESULTS: All groups displayed an initial decrease in blood flow during the first 3 days post-trauma. A recovery of the blood flow that even exceeded preoperative levels occurred in group A and later and to a lesser degree in group B, but not in group C. The amount of callus formation decreased with increasing trauma load. More cartilage was formed after 7 days in groups B and C than in group A. At later healing time points, callus composition did not differ significantly. CONCLUSIONS: An increasing injury burden causes a decreasing blood supply capacity and revascularization, and leads to impaired callus formation and an increasing delay in bone healing.

The effect of both a thoracic trauma and a soft-tissue trauma on fracture healing in a rat model.

BACKGROUND AND PURPOSE: There is some clinical evidence that fracture healing is impaired in multiply injured patients. Nothing is known, however, about the effects of various types of injuries and their contribution to a possible disturbance of the fracture-healing process. We investigated the effect of a thoracic trauma and an additional soft-tissue trauma on fracture healing in a rat tibia model. METHODS: 3 groups of rats were operated: group A with a simple fracture of the tibia and fibula, group B with a fracture and an additional thoracic trauma, and group C with a fracture, thoracic trauma, and an additional soft-tissue trauma. The fracture and the soft-tissue injury were produced by a special guillotine-like device and the thoracic trauma by a blast wave generator. After one day, the serum level of IL-6 was quantified, and at the end of the study (28 days) the mechanical properties and the callus volume of the healed tibia were determined. RESULTS: Increasing the severity of the injury caused IL-6 levels to more than double 1 day after injury. It halved the load to failure in mechanical tests and led to reduced callus volume after 28 days of healing. INTERPRETATION: Fracture healing is impaired when additional thoracic trauma and soft tissue trauma occurs.

Physiotherapy after volar plating of wrist fractures is effective using a home exercise program.

OBJECTIVE: To determine the effect of 2 different postoperative therapy approaches after operative stabilization of the wrist fractures: treatment by a physical therapist with 12 sessions and an unassisted home exercise program. DESIGN: Randomized controlled cohort study. SETTING: Hospital-based care, primary center of orthopedic surgery. PARTICIPANTS: Volunteers (N=48) with fractures of the distal radius after internal fixation with locking plates. There were 46 patients available for follow-up after exclusion of 2 participants due to physiotherapy sessions in excess of the study protocol. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Evaluation of grip strength using a Jamar dynamometer, range of motion (ROM), and Patient Related Wrist Evaluation (PRWE). RESULTS: After a 6-week period of postoperative treatment, the patients (n=23) performing an independent home exercise program using a training diary showed a significantly greater improvement of the functionality of the wrist. Grip strength reached 54% (P=.003), and ROM in extension and flexion 79% (P<.001) of the uninjured side. Ulnar and radial abduction was also higher in this group. In contrast, patients who were treated by a physical therapist achieved grip strength equal to 32%, and ROM in extension and flexion of 52% of the uninjured side. Patients who were performing the home training after operation recorded an improved wrist function with a nearly 50% lower value (P<.001) in the PRWE score. CONCLUSIONS: In the postoperative rehabilitation of wrist fractures, instructions in a home exercise program are an effective alternative to prescribed physical therapy treatment.

Effects of one-plane and two-plane external fixation on sheep osteotomy healing and complications.

OBJECTIVES: Comparison of one-plane and two-plane external fixation in terms of successful healing, incidence of complications, and biomechanical stability in a sheep model. BACKGROUND: Rigid fixation is preferred in open and comminuted fractures with a reduced blood supply, preventing infection and healing delay, but more often a flexible device is recommended even in unfavourable healing conditions. METHODS: The left tibiae of fifteen sheep were osteotomized and laterally fixed with a four-screw unilateral fixator frame (axial stiffness 183 N/mm) to a 3 mm gap size. In 9 of 15 sheep, an additional four-screw unilateral external fixator was anterolaterally attached (total axial stiffness of both frames 388 N/mm). After sacrificing, quality of osteotomy healing was assessed by mechanical and radiological evaluations. Osteogenesis was measured using fluorescence microscopy. RESULTS: Two distal fractures through the pin-tracks, three non-unions and four deep infections occurred after two-plane fixation. These failures excluded, osteotomy healing showed inferior results after two-plane fixation with reduced callus formation, bone mineral content, and bending stiffness amounts, respectively. Osteogenesis was halved following two-plane fixation in the remaining sheep. CONCLUSIONS: Two-plane fixation was not sufficient to reach successful osteotomy healing in our study. While higher rigidity was expected to prevent complications, healing in this group might have been disturbed by a reduced blood supply. The optimal stabilisation for a given fracture depends on many factors, including the biomechanical and biological environment. RELEVANCE: Considering our results and the literature discussed in this manuscript, good bone healing with minor risks of infections can be achieved using an unilateral one-plane fixator with only four screws, and its application on a muscle free position like the medial and anterior site of the sheep tibia.

Influence of preoperative mechanical bone quality and bone mineral density on aseptic loosening of total hip arthroplasty after seven years.

OBJECTIVE: To test mechanical bone quality and bone mineral density of the femoral head at the day of implantation as indicators for femoral prosthesis loosening. METHODS: Mechanical bone quality of a femoral head slice was assessed by destructive compression testing combined with bone mineral density measurements using peripheral quantitative computed tomography. Fourteen patients with walking pains were attainable for a radiographical follow-up mean 7.1 years after implantation. RESULTS: Radiolucent lines along the stem were evident in 11 of 14 femurs, most of them seen in Gruen zones 7, 6, 1, 3, 14, and showed strong correlations to preoperative bone strength (r=-0.80; P<0.001) and axial stiffness (r=-0.75; P=0.002), yet not to bone mineral density (r=-0.67; P=0.009). Slight varus deviations <3 degrees were noted in six femurs. Preoperative strength was reduced in this femurs to 54% (P=0.006), and stiffness to 61% (P=0.038), while bone mineral density did not differ significantly. CONCLUSIONS: Femoral prosthesis loosening after seven years can be predicted by mechanical bone quality of the femoral head at the time of implantation. Bone mineral density measurements may also indicate future stem loosening but have to interpreted carefully, keeping in mind a poorer predictive value. RELEVANCE: Indications and choice of type of hip arthroplasty should be balanced in osteoporotic bones in particular. While preoperative bone mineral density measurement allows the prediction of mechanical bone quality, its relevance in predicting failure in arthroplasty treatment remains unclear.

Effects of diclofenac on periosteal callus maturation in osteotomy healing in an animal model.

INTRODUCTION: Potential adverse effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on bone metabolism and fracture healing are contradictive to their wide application in post-traumatic treatment. Our objective was to investigate changes to periosteal callus formation with respect to NSAID and central analgesic drug application. Our hypothesis was that callus formation is delayed in animals treated with the non-specific NSAID diclofenac. MATERIALS AND METHODS: The left tibia of forty male Wistar rats were osteotomized, stabilized with a Kirschner wire, and randomized into four groups of ten animals. Group 1 received a placebo, group 2 received the central analgesic tramadol (20 mg/kg per day) throughout the study, and groups 3 and 4 were treated with sodium diclofenac (5 mg/kg per day). Group 3 received diclofenac for seven days, followed by placebo until sacrifice (short-term), while group 4 animals received diclofenac for the full period (long-term). Animals were sacrificed 21 days after osteotomy. RESULTS: Under light microscopy, all osteotomies healed successfully and independently of the drug treatment. Histomorphometry revealed delayed callus maturation in long-term diclofenac treated animals, with significantly higher amounts of cartilage and less bone, particularly in the outermost region of periosteal callus. Short-term NSAID and tramadol application did not significantly alter callus differentiation. CONCLUSION: Callus maturation in vivo was impaired after long-term application of diclofenac which corresponds to the in vitro findings of a dose-dependent effect of NSAIDs on osteoblast proliferation.