Radiographic landmark for humeral head rotation: a new radiographic landmark for humeral fracture fixation

Medial minimally invasive percutaneous plate osteosynthesis for humeral shaft fractures: a case series and novel technique description

INTRODUCTION

Minimally Invasive Percutaneous Plate Osteosynthesis (MIPPO) is increasingly favored for treating humeral shaft fractures (HSFs). However, conventional MIPPO techniques pose challenges in fixing fractures near fossa olecranon and carry a risk of iatrogenic radial nerve palsy. A novel technique using a medial MIPPO for treating humeral shaft fractures (HSFs) is described. Results of clinical follow-up are presented.

MATERIALS AND METHODS

This study is a retrospective case series study. Twenty-one patients (mean age 43.9 ± 17.66 [22‒81] years) with HSFs were treated with the novel MIPPO fixation method. Clinical outcomes including time for radiographic consolidation, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and complications were assessed at the last follow-up. The mean follow-up was 26 ± 17.12 (range 12-67) months.

RESULTS

All patients had a bony union at a mean of 15.76 ± 6.74 (range 8-40) weeks based on X-ray with an early and aggressive range of motion. The complication rate was 0. The mean DASH score was3.29 ± 4.09 (range 0-14.17) at the time of the last follow-up. The mean screw density was 0.49 ± 0.1 (range 0.2-0.65).

CONCLUSION

This novel surgical technique for HSFs is a viable alternative to previously described methods with the advantage of being less prone to nerve injury and easy to fix distal extra-articular HSFs. The learning curve is short.

LEVEL OF EVIDENCE

IV.

Radiographic rotational profiles of the proximal and distal humerus: analysis of 46 computed tomography scans with 3-dimensional simulation

BACKGROUND

To date, no study has investigated the radiographic rotational profiles (RRPs) of the proximal and distal humerus. However, malrotation after minimally invasive surgery for humeral fracture has been an unsolved problem. Therefore, we aimed to investigate the RRPs of the proximal and distal humerus that linearly correlate with rotational status and show significant differences as the rotational status changes.

METHODS

Forty-six computed tomography scans of the humerus were 3-dimensionally reconstructed, and 5 rotational statuses (20° and 10° of internal rotation; neutral; and 10° and 20° of external rotation) were simulated. Seven candidate RRPs of the proximal humerus and 4 candidates of the distal humerus were measured for each rotational status. The overall differences and trends in the RRPs as the rotational status changed were evaluated, and multiple comparisons were performed between the RRPs for each of the 5 rotational statuses. Moreover, the correlations between the RRPs and rotational status with adjustment of retroversion were analyzed. Finally, interobserver and intraobserver reliabilities were evaluated.

RESULTS

The following proximal and distal RRPs were linearly correlated with rotational status, differed significantly between the rotational statuses, and showed a relatively low prediction error and excellent interobserver and intraobserver reliabilities: the distance from the tip of the lesser tuberosity to the lateral margin of the proximal humerus (P_L1) and the medial margin of the head (P_L2), as well as the P_L1 to P_L2 ratio (PR_L), in the proximal humerus; and the distance from the medial margin of the olecranon process to the medial epicondyle (D_OP), the widest width of the overlapped olecranon fossa (D_OF), and the distance from the lateral margin of the capitellum to the lateral epicondyle (D_C) in the distal humerus.

CONCLUSION

Our findings suggest that P_L1, P_L2, and PR_L in the proximal humerus and D_OP, D_OF, and D_C in the distal humerus are potentially useful and reproducible RRPs for restoring the intrinsic rotational alignment in humeral fractures.

Implication of bone morphology in degenerative rotator cuff lesions: A prospective comparative study between greater tuberosity angle and critical shoulder angle

BACKGROUND

Degenerative rotator cuff tear is a frequent and multifactorial pathology. The role of bone morphology of the greater tuberosity and lateral acromion has been validated, and can be measured with two plain radiographic markers on true anteroposterior views: the greater tuberosity angle (GTA) and the critical shoulder angle (CSA). However, the interdependence of both markers remains unknown, as well as their relationship with the level of professional and sports activities involving the shoulder. The aim of this prospective comparative study was to describe the correlation between the GTA and CSA in patients with degenerative rotator cuff tears.

HYPOTHESIS

GTA and CSA are independent factors from one another and from demographic factors, such as age, dominance, sports, or professional activities.

PATIENT AND METHODS

All patients presenting to a shoulder specialized clinic were assigned to two groups. The first consisted of patients with a symptomatic degenerative rotator cuff tear visible on MRI and the control group consisted of patients with any other shoulder complaints and no history or visible imaging of any rotator cuff lesion.

RESULTS

There were 51 shoulders in 49 patients in the rotator cuff tear group (RCT) and 53 shoulders in 50 patients in the control group. Patient demographics were similar in both groups. Mean GTA was 72.1°±3.7 (71.0-73.1) in the RCT group and 64.0°±3.3 (63.1-64.9) in the control group (p<0.001). Mean CSA was 36.7°±3.7 (35.7-37.8) in the RCT group, and 32.1°±3.7 (31.1-33.1) in the control group (p<0.001). A summation of GTA and CSA values over 103° increased the odds of having a rotator cuff tear by 97-fold (p<0.001). There was no correlation between GTA and CSA, nor between GTA or CSA and age, sex, tear size, or dominance. Patients with different levels of professional and sports activities did not have significantly different GTA or CSA values.

CONCLUSION

GTA and CSA are independent radiologic markers that can reliably predict the presence of a degenerative rotator cuff tear. A sum of both values over 103° increases the odds of having a rotator cuff tear by 97-fold. These markers are not correlated with patient demographic or environmental factors, suggesting that the variability of the native acromion and greater tuberosity morphology may be individual risk factors for rotator cuff tear.

LEVEL OF EVIDENCE

II; diagnostic study.

Modified use of a proximal humeral internal locking system (PHILOS) plate in extra-articular distal-third diaphyseal humeral fractures

BACKGROUND

Surgical treatment of extra-articular distal-third diaphyseal humeral fractures is controversial in terms of surgical approach and position of implant. The aim of this study is to evaluate the clinical and radiological outcomes of a modified application of the proximal humeral internal locking system (PHILOS) plate in extra-articular distal-third diaphyseal humeral fractures.

MATERIALS AND METHODS

A total of 23 patients with extra-articular distal humerus fractures were treated using either open plating or the minimally invasive plate osteosynthesis (MIPO) technique with upside down application of the PHILOS plate. Fracture configuration, number of screws in the distal fragment, and time to union were analysed. Elbow range of motion, Mayo Elbow Performance Score (MEPS), and complications were evaluated at the final follow-up.

RESULTS

Fracture union was obtained in all patients at a mean postoperative time of 20.8 ± 2.9 weeks. The mean shortest and longest cortical lengths were 50.7 ± 14.0 mm and 85.2 ± 12.4 mm, respectively. The average number of screws in the distal humeral fragment was 5.6 ± 0.7. No statistically significant correlation was observed between the shortest cortical length and number of screws in the distal fragment (p = 0.224) or between the longest cortical length and the number of screws in the distal humeral fragment (p = 0.956). The average MEPS was 97.6 (range, 75-100). No postoperative complications that required reoperation were occured.

CONCLUSION

A modified anterior application of the PHILOS plate in extra-articular distal-third diaphyseal humeral fracture showed satisfactory outcomes, so it is an alternative when considering the ability to increase plate-screw density with locking screw fixation in a distal humeral fragment.

LEVEL OF EVIDENCE

Therapeutic level IV, case series.

The greater tuberosity angle: a new predictor for rotator cuff tear

BACKGROUND

The implication of scapular morphology in rotator cuff tears has been extensively studied. However, the role of the greater tuberosity (GT) should be of equal importance. The aim of this study was to propose a new radiographic marker, the GT angle (GTA), which measures the position of the GT in relation to the center of rotation of the humeral head. The hypothesis was that a higher angle value would be associated with a higher likelihood in detecting a rotator cuff tear.

METHODS

During 1 year, patients were prospectively recruited from a single institution specialized shoulder clinic in 2 different groups. The patient group consisted of individuals with a degenerative rotator cuff tear involving at least the supraspinatus. The control group consisted of individuals with no rotator cuff pathology. Individuals in both groups with congenital, post-traumatic, or degenerative alterations of the proximal humerus were excluded. The GTA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation by 3 observers at 2 different times.

RESULTS

The study recruited 71 patients (33 patients, 38 controls). Mean GTA value was 72.5° (range, 67.6°-79.2°) in patients and 65.2° (range, 55.8°-70.5°) for controls (P <.001). A value above 70° resulted in 93-fold higher odds of detecting a rotator cuff tear (P <.001). Interobserver and intraobserver reliability were high.

CONCLUSIONS

GT morphology is implicated in rotator cuff tears. The GTA is a reliable radiographic marker, with more than 70° being highly predictive in detecting such lesions.

Head-shaft angle changes during internal and external shoulder rotations: 2-D angulation in 3-D space

INTRODUCTION

Restoration of native head-shaft angle (HSA) is critical for treatment of proximal humerus fracture. However, HSA has not been properly investigated according to the humeral rotation. This study was designed to analyze the relationship between the humeral rotation and the HSA at 1° increments, and clarify its serial changing pattern according to the humeral rotation.

HYPOTHESIS

The angulation of HSA would be undervalued when the humerus is being rotated externally and it would be overvalued when it is being rotated internally.

MATERIALS AND METHODS

Eight dried cadaveric normal humeri were CT scanned. They were analyzed using computer-aided design with a standardized neutral position. HSA was the angle between the humeral shaft axis (SA) and the humeral head axis (HA). SA and HA were the best-fit lines through center of all the best-fitting circles in every cross section along the humeral shaft and within the humeral head, respectively. Each 3D model was rotated 30° internally and 45° externally relatives to the SA at 1° increments with the camera was fixed at antero-posterior view of neutral position. Angulation of HSA in every rotational degree was documented as ratio relatives to the angulation of HSA in neutral position.

RESULTS

The average HSA at neutral position was 133±1.93°. HSA was underestimated by 8±1.9% and it was overestimated by 20±5.1% at the maximum external rotation (ER) and internal rotation (IR), respectively. HSA was underestimated by 1% in every 5.8° of ER and overestimated by 1% in every 1.5° of IR. Rotational misalignments within 10° of IR and 18° of ER could be tolerated (P>.05).

CONCLUSIONS

HSA was underestimated at ER and was overestimated at IR. This information could be useful for surgeons in restoring the native HSA for treatment of proximal humerus fracture.

TYPE OF STUDY

Basic research study.