The diagnostic accuracy of Böhler's angle in fractures of the calcaneus.

BACKGROUND: Böhler's historical tuber-joint angle of the calcaneus has been used since 1931. Surprisingly, there is a paucity of literature on its use. OBJECTIVES: To confirm the normal range for Böhler's angle and determine the angle with the highest accuracy in the diagnosis of calcaneal fractures. METHODS: A retrospective cohort study was performed. The study cohort comprised 424 patients spanning a 5-year period from April 2005 to March 2010. Böhler's angle was measured by two independent observers on lateral x-ray study using the digital angle tool from the Picture Archival and Communication System. Data were analyzed using Stata 8 statistical software package. RESULTS: The mean Böhler's angle in patients without calcaneal fracture was 29.4°. In this group there was no difference in Böhler's angle between male and female patients, left and right feet, or across age. In those patients with calcaneal fractures, a Böhler's angle below 25° was moderately predictive of calcaneal fracture (sensitivity = 100%, specificity = 82%), an angle below 23° was highly predictive of calcaneal fracture (sensitivity = 100%, specificity = 89%), and an angle below 21° was strongly suggestive of calcaneal fracture (sensitivity = 99%, specificity = 99%). A Böhler's angle of ≤ 20° had the highest diagnostic accuracy. CONCLUSION: A Böhler's angle of 20° or less is highly accurate in determining the presence or absence of calcaneal fracture. Böhler's angle serves as a useful screening tool in fracture diagnosis.

Femoral insufficiency fractures associated with prolonged bisphosphonate therapy.

BACKGROUND: Emerging evidence has linked the long-term use of bisphosphonates with femoral insufficiency fractures. It has been suggested that the prolonged effect on bone remodeling leads to the accumulation of microfractures and weakening of bone. QUESTIONS/PURPOSES: We investigated the association between bisphosphonate use and femoral insufficiency fractures. METHODS: We evaluated 100 patients with low-energy femoral shaft fractures before and after bisphosphonates became available for use. Twenty-one consecutive patients who presented between January 1995 and February 1997 were compared with 79 consecutive patients who presented between January 2007 and February 2009. The radiographs of all 100 patients were examined for evidence of preexisting insufficiency fractures. We identified insufficiency fractures by a transverse fracture line on the tension side of the femur with lateral cortical thickening immediately adjacent to the fracture. Relevant details from the history were recorded. RESULTS: Forty-one patients had an underlying femoral insufficiency fracture, all of whom had been receiving bisphosphonate therapy. Among the 21 patients with low-energy femoral fractures before the availability of bisphosphonates, none had insufficiency fractures. Of the 41 patients with insufficiency fractures, 29 (71%) had prodromal pain and 18 (44%) had bilateral insufficiency fractures. Bisphosphonate use was associated (odds ratio greater than 1000) with insufficiency fracture. The mean duration of bisphosphonate use in patients with insufficiency fractures was longer than in patients without fractures (7.1 versus 3.2 years). CONCLUSION: Long-term bisphosphonate use is associated with insufficiency fractures of the femoral shaft, which commonly present with prodromal thigh pain and may be bilateral. These fractures were not seen before bisphosphonates became available for use.

Nitric oxide enhances collagen synthesis in cultured human tendon cells.

Collagen deposition is an important process that occurs during wound healing. We and others have shown that nitric oxide (NO) is important in tendon healing. The mechanisms whereby healing is enhanced are, however, undetermined. The aim of this study was to investigate whether NO could enhance collagen synthesis in cultured human tendon cells via exogenous NO and via an adenovirus containing the gene for inducible nitric oxide synthase (Ad-iNOS). Tendon cells from the torn edge of the tendons of patients undergoing rotator cuff repair surgery were cultured following collagenase digestion, and stimulated with exogenous NO (SNAP), transfected with Ad-iNOS, and treated with the NOS inhibitor, L-NMMA. Total protein and collagen synthesis were evaluated by (3)H-proline and collagenase sensitive (3)H-proline incorporation in human tendon cells. High doses of exogenous NO (SNAP) inhibited collagen synthesis. Lower doses enhanced total protein and collagen synthesis of the tendon cells. Ad-iNOS successfully transfected active iNOS into human tendon cells in vitro and also enhanced total protein and collagen synthesis of the tendon cells. The NOS inhibitor, L-NMMA, inhibited the effects of iNOS on the cells. Our studies show for first time that nitric oxide can enhance collagen synthesis in human tendon cells in vitro. These results may explain, in part, at least, the beneficial effects of NO donors in animal models and during the treatment of tendonopathies in human clinical trials. .

A randomised clinical trial evaluating the efficacy of physiotherapy after rotator cuff repair.

The optimal form of rehabilitation after rotator cuff repair has yet to be determined. A randomised clinical trial was undertaken to compare outcomes for two forms of rehabilitation for this condition: individualised supervised physiotherapy treatment, and a standardised unsupervised home exercise regime. Fifty-eight volunteers with all sizes of operatively repaired rotator cuff tears were allocated randomly to one of the two treatment groups. All subjects received a standardised home exercise regime. Subjects who were randomised to the physiotherapy group received additional individualised treatment. Independent, blinded assessments of range of motion, muscle force and functional outcome measures were performed pre-operatively, and at six, 12 and 24 weeks postoperation. At six, 12 and 24 weeks post-operation, comparable outcomes were demonstrated for both rehabilitation groups. By 24 weeks post-operation, most subjects demonstrated outcomes that were consistent with a favourable recovery, regardless of rehabilitation mode. On the basis of these results, outcomes for subjects allocated to individualised physiotherapy treatment after rotator cuff repair are no better than for subjects allocated to a standardised home exercise regime.

Rotator cuff repair with bioabsorbable screws: An in vivo and ex vivo investigation.

PURPOSE: The purpose of this study was to evaluate in vivo the clinical outcomes of rotator cuff repairs with bioabsorbable screws compared with metal suture anchors, and to compare the ex vivo initial load to failure of rotator cuff repairs using 3 different bioabsorbable screws, suture anchors, and transosseous sutures. TYPE OF STUDY: In vivo clinical outcomes investigation, and ex vivo biomechanical study. METHODS: Three cohorts of patients with rotator cuff tears that measured less than 4 cm(2), were sequentially repaired with Mitek Rotator Cuff QuickAnchors (Mitek Surgical Products, Norwood, MA) (n = 9), Arthrex Headed Bio-Corkscrews (n = 9) (Arthrex, Naples, FL), and Mitek Rotator Cuff QuickAnchors (n = 9). Patients were systematically assessed with a specific shoulder questionnaire and 23 shoulder tests performed preoperatively and at 1 and 6 weeks, 3 and 6 months, and 1 year postoperatively. A correlative ex vivo biomechanical study was performed on 53 ovine shoulders to evaluate the initial failure load properties of bioabsorbable screws compared with fixation with suture anchors and transosseous sutures. RESULTS: In the in vivo portion of the study, the cohort treated with the Headed Bio-Corkscrew demonstrated no improvement on any measured parameter until 1-year after rotator cuff repair. In contrast, shoulders repaired with Mitek Rotator Cuff QuickAnchors demonstrated improved overall shoulder function as early as 6 weeks postoperatively (P =.002), had a better constant score at 1-year after repair (88 +/- 9 v 73 +/- 17; P =.016), and a lower rate of revision rotator cuff repair (P =.029). In the ex vivo portion of the study, the bioabsorbable headed screws, Headed Bio-Corkscrew (100 +/- 30 N) and BioTwist (76 +/- 35 N), had inferior initial failure load properties compared with suture anchors (140 +/- 36 N) and transosseous sutures (147 +/- 68 N). In contrast, the BioCuff (190 +/- 56 N), a bioabsorbable implant that used a screw and serrated washer design, had equivalent initial failure load properties as the suture repairs. CONCLUSIONS: This investigation had poorer early outcomes, a lower shoulder functional score 1-year after repair, and a higher rate of repeat surgery in patients who had their rotator cuff repaired with a bioabsorbable screw than in patients who had their shoulders repaired with a standard metal suture anchor. Furthermore, the biomechanical testing demonstrated a lower tensile load to failure in the tendons repaired with a simple screw design compared to suture anchors with a mattress stitch. Of note, the implant that used a screw and washer design demonstrated a greater ability to resist initial tensile load.

Accuracy and reliability of arthroscopic estimates of cartilage lesion size in a plastic knee simulation model.

PURPOSE: The goal of the study was to determine the accuracy and reliability of arthroscopic percent area estimates in a plastic knee simulation model. A second goal was to determine the effect of lesion location within the knee and lesion size on accuracy and reliability. TYPE OF STUDY: Cross-sectional study of arthroscopic estimates of cartilage lesion size. METHODS: Three experienced arthroscopists performed 3 sets arthroscopic percent area estimates in 5 different plastic knees. Each knee had lesions drawn on 5 surfaces (patellar, medial and lateral femoral condyle, medial and lateral tibial plateaus). Accuracy and reliability were studied using Bland and Altman limits of agreement (LOA) and intraclass correlation coefficients. RESULTS: There was a strong tendency to overestimate lesion size by over 100% on the femoral and patellar surfaces. Intraobserver and interobserver reliabilities were generally poor. The range for the 95% LOA (+/- 1.96 standard deviation [SD] of the difference scores) between repeated measurements was almost 6 times the size of the lesion itself. Reliability of estimates was poorest for the largest lesions and worse at femoral, lateral tibial, and patellar sites. CONCLUSIONS: Assessments of arthroscopic measurements using LOA found that accuracy and reliability were generally poor, although results were better at the medial tibial plateau and for smaller lesions. In spite of these problems, arthroscopy remains a promising measurement tool because it permits physical assessment of cartilage integrity. This study sets the foundations for improvement in techniques of arthroscopic measurement of cartilage lesion size.

Supplementation of rotator cuff repair with a bioresorbable scaffold.

BACKGROUND: Repair of a torn rotator cuff should have sufficient initial strength of the fixation to permit appropriate rehabilitation. HYPOTHESIS: Augmentation with a woven polylactic acid scaffold strengthens repairs of the rotator cuff. STUDY DESIGN: Controlled laboratory study. METHODS: In the suture-anchor model, 10 pairs of sheep infraspinatus tendons were detached and repaired to suture anchors. In half of the matched specimens, the repair was reinforced with a woven poly-lactic acid scaffold repaired with the tendon to bone. In the bone-bridge model, sutures were passed through a trough and over a bone bridge distal to the greater tuberosity; half were reinforced by the scaffold. The repairs were tested to failure with a hydraulic testing machine. RESULTS: The mean ultimate strength of suture-anchor repairs augmented with the scaffold (167.3 +/- 53.9 N) was significantly greater than that of nonaugmented fixation (133.2 +/- 38.2 N). Failure occurred when the tendon pulled through the sutures; the scaffold remained intact. Scaffold reinforcement of the bone bridge significantly increased the ultimate strength from 374.6 +/- 117.6 N to 480.9 +/- 89.2 N, and the scaffold remained intact in 8 of 10 specimens. CONCLUSIONS: The scaffold significantly increased the initial strength of rotator cuff repair by approximately 25%.

Reliability of 3 methods for assessing shoulder strength.

The reliability of tests for isometric strength of the shoulder joint in symptomatic subjects has yet to be established. For this purpose, interrater and intrarater agreement trials were undertaken to ascertain the reliability of manual muscle tests, a handheld dynamometer, and a spring-scale dynamometer for 5 different shoulder movements in symptomatic subjects. Intraclass correlation coefficients were calculated from a random-effects model. All movements tested with the handheld dynamometer demonstrated excellent reliability for the interrater trial (rho = 0.79-0.92). Excellent reliability was also demonstrated for elevation, external rotation, and internal rotation for the intrarater trial (rho = 0.79-0.96). For the interrater trial, measurement of the lift-off maneuver with the handheld dynamometer was significantly more reliable than with manual muscle tests (P =.002). In summary, the handheld dynamometer was the most reliable and discriminatory means for assessing strength of the rotator cuff in symptomatic subjects.