Samy Bouaicha

Is there an association between the individual anatomy of the scapula and the development of rotator cuff tears or osteoarthritis of the glenohumeral joint?: A radiological study of the critical shoulder angle.

We hypothesised that a large acromial cover with an upwardly tilted glenoid fossa would be associated with degenerative rotator cuff tears (RCTs), and conversely, that a short acromion with an inferiorly inclined glenoid would be associated with glenohumeral osteoarthritis (OA). This hypothesis was tested using a new radiological parameter, the critical shoulder angle (CSA), which combines the measurements of inclination of the glenoid and the lateral extension of the acromion (the acromion index). The CSA was measured on standardised radiographs of three groups: 1) a control group of 94 asymptomatic shoulders with normal rotator cuffs and no OA; 2) a group of 102 shoulders with MRI-documented full-thickness RCTs without OA; and 3) a group of 102 shoulders with primary OA and no RCTs noted during total shoulder replacement. The mean CSA was 33.1° (26.8° to 38.6°) in the control group, 38.0° (29.5° to 43.5°) in the RCT group and 28.1° (18.6° to 35.8°) in the OA group. Of patients with a CSA > 35°, 84% were in the RCT group and of those with a CSA < 30°, 93% were in the OA group. We therefore concluded that primary glenohumeral OA is associated with significantly smaller degenerative RCTs with significantly larger CSAs than asymptomatic shoulders without these pathologies. These findings suggest that individual quantitative anatomy may imply biomechanics that are likely to induce specific types of degenerative joint disorders.

Relationship of individual scapular anatomy and degenerative rotator cuff tears

BACKGROUND The etiology of rotator cuff disease is age related, as documented by prevalence data. Despite conflicting results, growing evidence suggests that distinct scapular morphologies may accelerate the underlying degenerative process. The purpose of the present study was to evaluate the predictive power of 5 commonly used radiologic parameters of scapular morphology to discriminate between patients with intact rotator cuff tendons and those with torn rotator cuff tendons. METHODS A pre hoc power analysis was performed to determine the sample size. Two independent readers measured the acromion index, lateral acromion angle, and critical shoulder angle on standardized anteroposterior radiographs. In addition, the acromial morphology according to Bigliani and the acromial slope were determined on true outlet views. Measurements were performed in 51 consecutive patients with documented degenerative rotator cuff tears and in an age- and sex-matched control group of 51 patients with intact rotator cuff tendons. Receiver operating characteristic analyses were performed to determine cutoff values and to assess the sensitivity and specificity of each parameter. RESULTS Patients with degenerative rotator cuff tears demonstrated significantly higher acromion indices, smaller lateral acromion angles, and larger critical shoulder angles than patients with intact rotator cuffs. However, no difference was found between the acromial morphology according to Bigliani and the acromial slope. With an area under the receiver operating characteristic curve of 0.855 and an odds ratio of 10.8, the critical shoulder angle represented the strongest predictor for the presence of a rotator cuff tear. CONCLUSION The acromion index, lateral acromion angle, and critical shoulder angle accurately predict the presence of degenerative rotator cuff tears.

Association Between Mechanical Axis of the Leg and Osteochondritis Dissecans of the Knee Radiographic Study on 103 Knees

Background: The cause of osteochondritis dissecans (OCD) is unknown, but mechanical factors seem to play a role. Purpose: To identify a relationship between localization of OCD and mechanical axis of the leg. Study Design: Case series; Level of evidence, 4. Methods: Using bilateral full-leg standing radiographs, we analyzed the position of the mechanical axis of the leg in a group of 93 adolescent and adult patients (103 knees) with OCD of the medial or lateral femoral condyle. Results: The location of OCD and the position of the mechanical axis in the same knee compartment was significantly correlated for both knees with medial (P < .001) as well as lateral (P < .012) compartment OCD. In the medial OCD group, the mean mechanical axis was located in the medial knee compartment (28% medial ± 2.8%; range, 100% medial to 14% lateral) with a statistically insignificant medial shift with respect to the unaffected side. In lateral OCD, the mean mechanical axis was located laterally (13% lateral ± 3.9%; range, 13% medial to 60% lateral) with a significant shift from the medial into the lateral knee compartment when comparing unaffected with affected knees. No significant difference was observed between adolescents with open growth plates compared with adults with closed growth plates (P > .05). Conclusion: We found an association between medial condyle OCD and varus axis and between lateral condyle OCD and valgus axis. This evokes higher loading of the affected than of the unaffected knee compartment, and therefore, axial alignment may be a cofactor in OCD of the femoral condyles.

Reconstruction of the medial patellofemoral ligament using the adductor magnus tendon: an anatomic study.

PURPOSE The aims of this study were to evaluate the anatomic feasibility of medial patellofemoral ligament (MPFL) reconstruction using a part of the adductor magnus tendon and to identify possible risks. METHODS Twenty cadaveric knees were dissected. The distal part of the adductor magnus tendon was evaluated with respect to the anatomic topography and its utility for MPFL reconstruction. To estimate the risk of injuring the neurovascular structures, the distance from the adductor tubercle to the adductor hiatus was evaluated. An MPFL reconstruction was carried out by preserving the distal insertion on the adductor tubercle and redirecting the proximal portion of the tendon to the medial aspect of the patella. RESULTS The anatomic investigation showed the following relationships: The mean distance from the adductor tubercle to the adductor hiatus was 99 ± 14 mm (range, 80 to 120 mm). A graft length of 52 ± 5 mm (range, 45 to 63 mm) with the addition of 10 to 20 mm for fixation was found to be necessary for MPFL reconstruction. The difference between the desired graft length and the distance to the adductor hiatus was found to be at least 30 mm in all cases (mean, 46 mm). Leaving the graft attached to the adductor tubercle resulted in a nearly anatomic femoral attachment of the reconstructed MPFL. Complete detachment of the distal adductor magnus attachment was consistently avoidable. CONCLUSIONS The adductor magnus tendon was found to be a useful graft for MPFL reconstruction. However, anatomic dangers (damage to the neurovascular bundle of the adductor hiatus, the saphenous nerve, or the saphenous branch of the descending genicular artery) during graft harvest must be considered. CLINICAL RELEVANCE Anatomic knowledge is essential during adductor magnus tendon harvest to avoid damage to neurovascular structures. The adductor magnus tendon is an interesting alternative graft option for MPFL reconstruction if anatomic dangers are considered and avoided.

Results after delayed axillary nerve reconstruction with interposition of sural nerve grafts

HYPOTHESIS Satisfactory results after repair of isolated axillary nerve lesions using sural nerve autografts have been reported, but a delay between injury and surgical repair exceeding 6 months was one of the most important negative predictors of functional outcome. From our experience, we hypothesize that good results can be obtained even after a delay exceeding 6 months and we opted in this study to assess the value of delayed axillary nerve reconstruction. MATERIALS AND METHODS We evaluated clinical outcome and donor-site morbidity in 12 patients (mean age, 37; range, 19-66 years) who underwent axillary nerve repair with sural nerve graft with an average 11.25-month a delay between trauma and surgery (range, 8-20 months). Follow-up examination at least 24 months after treatment included assessment of shoulder range of motion, deltoid muscle strength in near full extension, deltoid extension lag, and sensibility. Constant Score, subjective shoulder value, and the Disabilities of Arm, Shoulder and Hand score were also assessed. RESULTS All patients showed an improved deltoid function of at least M3. Postoperative extension lag, as the most specific sign of isolated deltoid function, improved from 57.5 degrees to 14.2 degrees. All stated that they would have identical elective surgery again. Relevant donor-site morbidity was not observed. CONCLUSION Our data indicate that even delayed axillary nerve grafting may lead to satisfactory functional results with a low morbidity and should therefore be done in selected patients.

Radiographic Analysis of Metatarsus Primus Elevatus and Hallux Rigidus

Background: Controversy exists about the role of metatarsus primus elevatus (MPE) in the presence of hallux rigidus. Previous studies could neither confirm nor reject a causative relationship. Measurement of the true elevation of the first metatarsal according to current techniques lack either precision or accuracy or both. The purpose of this study was to assess MPE by means of a new radiographic measurement method and to analyze how the MPE-values differed among hallux rigidus, hallux valgus and control groups. Materials and Methods: A retrospective study was performed of standing AP and lateral radiographs of 295 feet (221 patients; average age 54 years) randomly selected from our databank. According to general radiographic and clinical criteria, 99 were defined as hallux rigidus. Ninety-nine feet had a hallux valgus deformity without severe arthritis. Ninety-seven radiographs with normal MP-I joints and no other forefoot deformity served as a control group. The elevation of the first metatarsal bone in relation to the second metatarsal (MPE), the first metatarsopahlangeal dorsiflexion angle (DFA), the hallux valgus angle (HVA), the intermetatarsal angle (IMA), the interphalangeal angle (IPA) and the degeneration of the first metatarsophalangeal joint were measured. Three independent raters were involved to assess the inter-rater reliability of a new MPE measurement method. For statistic analyses, ANOVA testing was used. Results: MPE was significantly greater in patients with hallux rigidus (+5.2 mm; 95% CI: 4.7 to 5.7) when compared with hallux valgus (+2.8 mm; 95% CI: 2.2 to 3.4) or the control group (+2.6; 95% CI: 2.0–3.2; p < 0.0001). The DFA was found to be significantly lower in the hallux rigidus group (9 degrees; 95% CI: 8 to 10) when compared with those measured in the hallux valgus (14 degrees; 95% CI: 13 to 16) and control groups (11 degrees; 95% CI: 10 to 12; p < 0.0001). There was a no correlation found between MPE and osteoarthritis at MP-I joint (r = 0.35; p < 0.0001). A moderate correlation was found between increasing MPE and decreasing DFA (r = 0.5; p < 0.0001). The inter-rater reliability of the MPE measurement method was found to be accurate and reproducible (r = 0.9; p < 0.0001). Conclusion: Based on the findings in this study, an MPE greater than 5 mm could be considered a predictive factor in the presence of hallux rigidus. However, the mechanism of MPE has yet to be determined. Level of Evidence: III, Case Control Series

Inclination-dependent changes of the critical shoulder angle significantly influence superior glenohumeral joint stability

BACKGROUND The critical shoulder angle combines the acromion index and glenoid inclination and has potential to discriminate between shoulders at risk for rotator cuff tear or osteoarthritis and those that are asymptomatic. However, its biomechanics, and particularly the role of the glenoid inclination, are not yet fully understood. METHODS A shoulder simulator was used to analyze the independent influence of glenoid inclination during abduction from 0 to 60°. Spindle motors transferred tension forces by a cable-pulley on human cadaveric humeri. A six-degree-of-freedom force transducer was mounted directly behind the polyethylene glenoid to measure shear and compressive joint reaction force and calculate the instability ratio (ratio of shear and compressive joint reaction force) with the different force ratios of the deltoid and supraspinatus muscles (2:1 and 1:1). A stepwise change in the inclination by 5° increments allowed simulation of a critical shoulder angle range of 20° to 45°. FINDINGS Tilting the glenoid to cranial (increasing the critical shoulder angle) increases the shear joint reaction force and therefore the instability ratio. A balanced force ratio (1:1) between the deltoid and the supraspinatus allowed larger critical shoulder angles before cranial subluxation occurred than did the deltoid-dominant ratio (2:1). INTERPRETATION Glenoid inclination-dependent changes of the critical shoulder angle have a significant impact on superior glenohumeral joint stability. The increased compensatory activity of the rotator cuff to keep the humeral head centered may lead to mechanical overload and could explain the clinically observed association between large angles and degenerative rotator cuff tears.

Location of Sternal Fractures as a Possible Marker for Associated Injuries

Introduction. Sternal fractures often occur together with serious and life-threatening additional injuries. This retrospective study was designed to assess concomitant injuries and develop a correlation between fracture location and the severity of injury. Methods. All patients (n = 58) diagnosed with a fracture of the sternum by means of a CT scan were analysed with respect to accident circumstances, fracture morphology and topography, associated injuries, and outcome. Results. Isolated sternal fractures occurred in 9%. In all other admissions, concomitant injuries were diagnosed: mainly rip fractures (64%), injury to the head (48%), the thoracic spine (38%), lumbar spine (27%), and cervical spine (22%). Predominant fracture location was the manubrium sterni. In these locations, the observed mean ISS was the highest. They were strongly associated with thoracic spine and other chest injuries. Furthermore, the incidence of head injuries was significantly higher. ICU admission was significantly higher in patients with manubrium sterni fractures. Conclusion. Sternal fractures are frequently associated with other injuries. It appears that the fracture location can provide important information regarding concomitant injuries. In particular, in fractures of manubrium sterni, the need for further detailed clinical and radiologic workup is necessary to detect the frequently associated injuries and reduce the increased mortality.

Early Serum Procalcitonin Level after Primary Total Hip Replacement

Background. Procalcitonin (PCT) is a useful surrogate marker for the differentiation of postoperative infection and unspecific inflammatory reaction after surgery. It is known that postoperative course of the PCT serum level varies with type of surgery. No data exists about the postoperative course of serum PCT levels after primary total hip replacement (THR). Purpose. To characterize early postoperative serum PCT levels in uneventful primary THR compared to postoperative levels of different frequently used inflammatory blood parameters. Method. We prospectively investigated 31 patients. Blood samples were taken preoperatively and for 5 days postoperatively. PCT levels were compared with C-reactive protein (CRP), interleukin-6 (IL-6), and blood leucocyte counts (WBC). Results. In uneventful THR PCT levels showed a uniform low-level course with a peak at the second postoperative day. At the fifth day values returned to almost preoperative levels. On contrary, CRP levels remained high during the entire observational period. Only IL-6 levels showed a peak at postoperative day one with a quick and uniform return to preoperative levels. Conclusion. Similar to observations in cardiothoracic, intestinal, and neural surgeries, postoperative course of PCT after primary THR showed a uniform low-level course with a peak at the second postoperative day but below expected levels in systemic infections.

Cross-Sectional Area of the Rotator Cuff Muscles in MRI - Is there Evidence for a Biomechanical Balanced Shoulder?

Objective To provide in-vivo evidence for the common biomechanical concept of transverse and craniocaudal force couples in the shoulder that are yielded by both the rotator cuff muscles (RCM) and the deltoid and to quantitatively evaluate and correlate the cross-sectional areas (CSA) of the corresponding RCM as a surrogate marker for muscle strength using MRI. Materials and Methods Fifty patients (mean age, 36 years; age range, 18–57 years; 41 male, 9 female) without rotator cuff tears were included in this retrospective study. Data were assessed by two readers. The CSA (mm2) of all rotator cuff muscles was measured on parasagittal T1-weighted FSE sequence at two different positions (at the established “y-position” and at a more medial slice in the presumably maximal CSA for each muscle, i.e., the “set position”). The CSA of the deltoid was measured on axial intermediate-weighted FSE sequences at three positions. CSA measurements were obtained using 1.5 Tesla MR-arthrographic shoulder. Pearson’s correlation for the corresponding CSA of the force couple as well as was the intraclass correlation coefficient for the inter- and intra-reader agreement was calculated. Results The mean CSA was 770 mm2 (±167) and 841 mm2 (±191) for the supraspinatus (in the y- and set-positions, respectively) and 984 mm2 (±241) and 1568 mm2 (±338) for the infraspinatus. The mean CSA was 446 mm2 (±129) and 438 mm2 (±128) for the teres minor (in the y- and set-positions, respectively) and 1953 mm2 (±553) and 2343 mm2 (±587) for the subscapularis. The three measurements of the deltoid revealed a CSA of 3063 mm2 (±839) for the upper edge, 3829 mm2 (±836) for the lower edge and 4069 mm2 (±937) for the middle of the glenoid. At the set position Pearson’s correlation of the transverse force couple (subscapularis/infraspinatus) showed a moderate positive correlation of r = 0.583 (p<0.0001) and a strong correlation when the CSA of the teres minor was added to the infraspinatus CSA (r = 0.665, p = 0.0008) and a strong positive correlation of the craniocaudal force couple (supraspinatus/deltoid) that ranged from r = 0.565–0.698 (p<0.0001). Inter-reader agreement (ranged from 0.841 to 0.997, p = 0.0007) and intra-reader agreement were excellent (ranged from 0.863 to 0.999, p = 0.0006). Conclusion The significant correlation of the CSA of the RCM that form the transverse (subscapularis/infraspinatus-teres minor) and craniocaudal (supraspinatus/deltoid) force couple measured by MR-arthrography supports the biomechanical concept of a dynamically balanced shoulder in patients with an intact rotator cuff.