Management of Joint Contractures in the Spastic Upper Extremity.

Upper extremity contractures in the spastic patient may result from muscle spasticity, secondary muscle contracture, or joint contracture. Knowledge of the underlying cause is critical in planning successful treatment. Initial management consists of physical therapy and splinting. Botulinum toxin can be helpful, as a therapeutic treatment in relieving spasticity and as a diagnostic tool in determining the underlying cause of the contracture. Surgical management options include release or lengthening of the causative muscle/tendon unit and joint capsular release, as required. Postoperative splinting is important to maintain the improved range of motion and protect any associated tendon lengthening or transfer.

Assessing functional recovery shortly after knee or hip arthroplasty: a comparison of the clinimetric properties of four tools.

BACKGROUND: Following hip or knee arthroplasty, it is clinically warranted to get patients functional as quickly as possible. However, valid tools to assess function shortly after knee or hip arthroplasty are lacking. The objective was to compare the clinimetric properties of four instruments to assess function shortly after arthroplasty. METHODS: One hundred eight patients undergoing hip or knee arthroplasty were assessed preoperatively, 1 and 2 days postoperatively, and 2 and 6 weeks postoperatively with the Timed Up and Go (TUG), Iowa Level of Assistance Scale (ILAS), Postoperative Quality of Recovery Scale (PQRS), and Readiness for Hospital Discharge Scale (RHDS). Descriptive data, floor and ceiling effects, responsiveness, interpretation and construct validity were determined. RESULTS: Only the ILAS and RHDS support subscale demonstrated floor or ceiling effects. A large deterioration from preoperative to postoperative, followed by large improvements after surgery were seen in the TUG and ILAS scores. The RHDS personal status subscale and the PQRS pain and function dimensions demonstrated large improvements after surgery. Changes in the RHDS global scale and personal status subscale, PQRS pain dimension and TUG were significantly related to patient perceived improvement. Minimal important changes were obtained for the RHDS global (1.1/10) and personal status subscale (2.3/10), and the TUG (43.4 s at 6 weeks). For construct validity, the PQRS function dimension and RHDS were moderately related to the TUG or ILAS. The correlation between TUG and ILAS was high from preoperative to postoperative day 2, but substantially decreased at 2 and 6 weeks. CONCLUSIONS: The TUG and RHDS personal status subscale demonstrated the best clinimetric properties to assess function in the first 6 weeks after hip or knee arthroplasty.

The return of subscapularis strength after shoulder arthroplasty.

BACKGROUND: During shoulder arthroplasty, the subscapularis tendon is released and repaired. Whether subscapularis strength subsequently returns to normal is poorly understood. This study's purpose was to determine whether subscapularis strength returns to normal after shoulder replacement and whether any preoperative factors predict the return of strength postoperatively. METHODS: Sixty-four patients underwent unilateral shoulder arthroplasty. Subscapularis strength was compared between the surgical and contralateral (normal) limbs at baseline (preoperatively) and follow-up. In addition, operative arm subscapularis strength recovery was compared with ipsilateral supraspinatus strength recovery. Independent variables were assessed for their effect on subscapularis strength, including sex, age, dominant-side surgery, preoperative strength, preoperative external rotation, subscapularis management technique, and fatty infiltration. RESULTS: The mean subscapularis strength ratio at 24 months from baseline was 1.19 ± 2.23 (P = .0007). The normal side was significantly stronger than the operative side at all time points (P < .0001). The operative-side subscapularis mean strength ratio was 0.54 ± 0.28 of normal at baseline and 0.70 ± 0.24 at 24 months. Defining normal strength as ±15%, 15% of patients were normal at baseline up to 22% at 24 months. At 24 months, the mean supraspinatus strength ratio from baseline (3.13 ± 6.11) was significantly greater than the subscapularis mean strength ratio (P = .0007). Multivariable regression analysis did not demonstrate any correlation (P > .05) between the independent variables studied and final subscapularis strength. DISCUSSION: Although significant strength improvement from baseline was observed at 2 years after shoulder arthroplasty, subscapularis strength returned to normal in only a minority of patients. Potential prognostic variables associated with final subscapularis strength remain elusive.

Factors affecting transfusion requirement after hip fracture: can we reduce the need for blood?

BACKGROUND: Hip fractures are common injuries that result in blood loss and frequently require the transfusion of blood products. We sought to identify risk factors leading to increased blood transfusion in patients presenting with hip fractures, especially those factors that are modifiable. METHODS: We retrospectively reviewed the cases of all patients who had fixation of their hip fractures between October 2005 and February 2010. The need for transfusion was correlated with potential risk factors, including age, sex, preoperative hemoglobin, fracture type, fixation method and more. RESULTS: A total of 835 patients had fixation of their hip fractures during the study period; 631 met the inclusion criteria and 249 of them (39.5%) were transfused. We found an association between need for blood transfusion and female sex (p = 0.018), lower preoperative hemoglobin (p < 0.001), fracture type (p < 0.001) and fixation method (p < 0.001). Compared with femoral neck fractures, there was a 2.37 times greater risk of blood transfusion in patients with intertrochanteric fractures (p < 0.001) and a 4.03 times greater risk in those with subtrochanteric fractures (p < 0.001). Dynamic hip screw (DHS) fixation decreased the risk of transfusion by about half compared with intramedullary nail or hemiarthroplasty. We found no association with age, delay to operation (p = 0.17) or duration of surgery (p = 0.30). CONCLUSION: The only modifiable risk factor identified was fixation method. When considering blood transfusion requirements in isolation, we suggest a potential benefit in using a DHS for intertrochanteric and femoral neck fractures amenable to DHS fixation.

CONTEXTE: La fracture de la hanche est un traumatisme fréquent, qui cause une perte sanguine et nécessite souvent la transfusion de produits sanguins. Nous avons tenté d'identifier les facteurs de risque associés à une hausse du nombre des transfusions sanguines chez des patients ayant subi une fracture de la hanche, en particulier les facteurs modifiables. MÉTHODES: Au cours d'une étude rétrospective, on a revu les cas de tous les patients chez qui on avait pratiqué une ostéosynthèse pour une fracture de la hanche survenue entre octobre 2005 et février 2010. La nécessité d'une transfusion sanguine a été associée à d'éventuels facteurs de risque, dont l'âge, le sexe, le taux d'hémoglobine préopératoire, le type de fracture, la technique d'ostéosynthèse, et d'autres facteurs encore. RÉSULTATS: Au total, 835 patients avaient subi une ostéosynthèse pour fracture de la hanche au cours de la période à l'étude; 631 satisfaisaient les critères d'inclusion à l'étude et parmi eux, 249 (39,5 %) ont reçu une transfusion sanguine. On a observé l'existence d'un lien entre la nécessité d'une transfusion sanguine et le sexe féminin (p = 0,018), une plus faible concentration d'hémoglobine préopératoire (p < 0,001), le type de fracture (p <0,001) et la technique d'ostéosynthèse (p < 0,001). Par rapport aux fractures du col fémoral, le risque de transfusion sanguine était 2,37 fois plus élevé chez les patients présentant une fracture intertrochantérienne (p < 0,001) et 4,03 fois plus élevé chez ceux présentant une fracture sous-trochantérienne (p <0,001). En utilisant une vis dynamique de hanche, le risque de transfusion sanguine a diminué d'environ 50 % par rapport à l'enclouage centromédullaire ou à l'hémiarthroplastie. Aucun lien n'a été observé avec l'âge, le délai de l'intervention chirurgicale (p = 0,17), ni avec sa durée (p = 0,30). CONCLUSION: La technique d'ostéosynthèse est l'unique facteur de risque modifiable ayant été identifié. Mais lorsqu'on évalue la nécessité d'une transfusion sanguine sans tenir compte des facteurs de risque, nos résultats semblent indiquer qu'on aurait avantage à utiliser une vis dynamique de hanche pour consolider les fractures intertrochantériennes et les fractures du col fémoral.

Role of the asymmetry of the homodimeric b2 stator stalk in the interaction with the F1 sector of Escherichia coli ATP synthase.

The b subunit dimer in the peripheral stator stalk of Escherichia coli ATP synthase is essential for enzyme assembly and the rotational catalytic mechanism. Recent protein chemical evidence revealed the dimerization domain of b to contain a novel two-stranded right-handed coiled coil with offset helices. Here, the existence of this structure in more complete constructs of b containing the C-terminal domain, and therefore capable of binding to the peripheral F1-ATPase, was supported by the more efficient formation of intersubunit disulfide bonds between cysteine residues that are proximal only in the offset arrangement and by the greater thermal stabilities of cross-linked heterodimers trapped in the offset configuration as opposed to homodimers with the helices trapped in-register. F1-ATPase binding analyses revealed the offset heterodimers to bind F1 more tightly than in-register homodimers. Mutations near the C terminus of b were incorporated specifically into either the N-terminally or the C-terminally shifted polypeptide, bN or bC, respectively, to determine the contribution of each position to F1 binding. Deletion of the last four residues of bN substantially weakened F1 binding, whereas the effect of the deletion in bC was modest. Similarly, benzophenone maleimide introduced at the C terminus of bN, but not bC, mediated cross-linking to the delta subunit of F1. These results imply that the polypeptide in the bN position is more important for F1 binding than the one in the bC position and illustrate the significance of the asymmetry of the b dimer in the enzyme.

Mutations in the dimerization domain of the b subunit from the Escherichia coli ATP synthase. Deletions disrupt function but not enzyme assembly.

The b subunit dimer of Escherichia coli ATP synthase serves essential roles as an assembly factor for the enzyme and as a stator during rotational catalysis. To investigate the functional importance of its coiled coil dimerization domain, a series of internal deletions including each individual residue between Lys-100 and Ala-105 (b(deltaK100)-b(deltaA105)), b(deltaK100-A103), and b(deltaK100-Q106) as well as a control b(K100A) missense mutation were prepared. All of the mutants supported assembly of ATP synthase, but all single-residue deletions failed to support growth on acetate, indicating a severe defect in oxidative phosphorylation, and b(deltaK100-Q106) displayed moderately reduced growth. The membrane-bound ATPase activities of these strains showed a related reduction in sensitivity to dicyclohexylcarbodiimide, indicative of uncoupling. Analysis of dimerization of the soluble constructs of b(deltaK100) and the multiple-residue deletions by sedimentation equilibrium revealed reduced dimerization compared with wild type for all deletions, with b(deltaK100-Q106) most severely affected. In cross-linking studies it was found that F1-ATPase can mediate the dimerization of some soluble b constructs but did not mediate dimerization of b(deltaK100) and b(deltaK100-Q106); these two forms also were defective in F1 binding analyses. We conclude that defective dimerization of soluble b constructs severely affects F1 binding in vitro, yet allows assembly of ATP synthase in vivo. The highly uncoupled nature of enzymes with single-residue deletions in b indicates that the b subunit serves an active function in energy coupling rather than just holding on to the F1 sector. This function is proposed to depend on proper, specific interactions between the b subunits and F1.