Radiological evaluation of patellofemoral instability and possible causes of assessment errors: Letter to the editor

This letter to the editor is a commentary on the study titled "Radiological evaluation of patellofemoral instability and possible causes of assessment errors". There are some pertinent structural changes and radiological findings that should be considered in the setting of traumatic knee injuries, as their recognition is of paramount importance.

The pivot fracture: an unusual tibial plateau fracture found in association with acute ACL injury

Tibial plateau fractures are common fractures which are often associated with concurrent soft tissue injury and for which accurate preoperative diagnosis is important for development of an appropriate treatment plan and outcome prediction. Here, we present an extreme manifestation of the pivot shift phenomenon with an unusual tibial plateau fracture with flipped component not described by any existing tibial plateau fracture classification system and never reported previously in conjunction with an anterior cruciate ligament injury. We describe the utilization of advanced imaging not typically utilized in the management of tibial plateau fractures in combination with clinical suspicion to diagnose the associated soft tissue injuries and develop an appropriate management plan.

Imaging of Patellofemoral Instability

Patellar instability is a broad term that encompasses patellar dislocation, patellar subluxation, and patellar instability. Although both functional and anatomic considerations contribute to symptoms of patellar instability, the most important are thought to be patella alta, trochlear dysplasia, and lateralization of the tibial tubercle. In patients with a history suspicious for prior patellar dislocation, careful evaluation of MRI and radiographic studies can reveal characteristic findings. The most common methods to address patellofemoral instability are medial patellofemoral ligament reconstruction and tibial tubercle osteotomy with either anteromedialization or medialization. Less commonly trochleoplasty is indicated as well. Patients may be treated with one of or a combination of these techniques, each of which has specific indications and complications.

Stress reactions and fractures around the elbow in athletes

Stress fractures of the upper limb affect athletes from a wide range of sports. Athletes involved in throwing sports are particularly susceptible along with athletes from sports involving high repetitive and compressive loads such as gymnastics. Diagnosis can be made from clinical history, examination and radiography in some cases however MRI imaging is often required for definitive diagnosis. The mainstay of management is rest and activity modification however advanced pathology often requires surgical management for successful resolution and return to play. In the elbow, the bones susceptible to excessive stress in sport are the distal humerus, the olecranon process of the ulna, the coronoid process of the ulna, the sublime tubercle and the radial head. In immature patients, medial epicondyle apophysis is the most common location. The article presents a narrative review of the literature.

Magnetic Resonance Imaging Evaluation of the Anterolateral Ligament and the Iliotibial Band in Acute Anterior Cruciate Ligament Injuries Associated With Segond Fractures

PURPOSE

To evaluate the magnetic resonance imaging (MRI) characteristics of Segond fractures, including the structures attached to the avulsed fragment, the integrity of anterolateral ligament (ALL) and iliotibial band (ITB), and fragment size and location.

METHODS

This was a retrospective, cross-sectional study with MRI scans from 2016 to 2019 with the term "Segond" in the reports, signs of acute trauma, and a bony anterolateral tibial avulsion (Segond) fracture. Two experienced observers accessed images to evaluate fragment dimensions (anteroposterior, mediolateral, and craniocaudal) and distances from anatomic landmarks (Gerdy's tubercle, articular surface, and posterolateral tibial corner). ALLs and ITBs also were evaluated, both for integrity and for attachment to the avulsed bony fragment. Data were statistically evaluated for significant correlations.

RESULTS

Forty-eight knee MRIs of patients suffering from a combined anterior cruciate ligament and Segond injury were evaluated. The ALL presented with edema in 28 cases (58.3%) and was torn in 3 cases (6.3%). The ALL was attached to the bone fragment in all cases and the ITB also was attached in 25 cases (52.1%). Receiver operating characteristic curves also demonstrated that the larger each of the dimensions and the volume of the fragment, the greater the probability of ITB fibers being inserted. Also, the narrower the distance from the fragment to the center of Gerdy's tubercle, the greater the probability of iliotibial band fibers being attached. Interobserver correlation varied from 0.87 to 0.97 for all measurements.

CONCLUSIONS

In all combined ACL injuries and Segond fracture MRI cases, the complete ALL inserted on the avulsed bony fragment, whereas the posterior part of the ITB was only attached in 52.1% of the cases. Segond fracture fragment size was predictive for the structures attached to it. The ALL was abnormal in 64.5% of cases and presented a clear discontinuity in 6.3%.

LEVEL OF EVIDENCE

Case Series, Level IV.

Part II: presentation, diagnosis, classification, treatment, and prevention of stress fractures in female athletes

Objectives: Stress fractures (SFx) occur as the result of repetitive loads over short periods of time, which leads to micro-damage of the bone through cortical resorption, ultimately leading to fracture. They are a common injury in female athletes and often cause significant morbidity. The goal of this study is to review the presentation, diagnosis, classification, treatment, and prevention of SFx in female athletes.Results: A thorough history, physical exam, and appropriate imaging can facilitate early diagnosis of stress fracture (SFx) and faster resolution of symptoms with more conservative management. The female athlete triad is an especially important factor that contributes to the increased risk of SFx in females. The continuum of stress injuries ranges from mild microfailure to complete fracture, which has resulted in the development of newer grading schemas through MRI and radiographic findings. Stress fractures are also classified as low- or high-risk according to anatomic location, as blood supply and applied forces at different locations affect the likelihood of fracture propagation, displacement, delayed union, or non-union.Conclusions: The ability to screen for at-risk athletes is paramount in preventing SFx. Recognition and prompt treatment of the female athlete triad requires a multidisciplinary approach in order to restore energy balance, correct menstrual irregularities, and improve bone health. This review provides a basis for understanding how to identify and treat stress fractures, which may allow treating physicians to diagnose this condition earlier and minimize any associated morbidity.

Analysis of Bony and Internal Organ Injuries Associated With 26,357 Adult Femoral Shaft Fractures and Their Impact on Mortality

The spectrum of injuries associated with femoral shaft fractures and those injuries' association with mortality have not been well delineated previously. Patients in the National Trauma Data Bank who presented with femoral shaft fractures from 2011 to 2012 were analyzed in 3 age groups (18-39, 40-64, and 65+ years). For each group, modified Charlson Comorbidity Index (CCI), mechanism of injury (MOI), injury severity score (ISS), and associated injuries were reported. Multivariate logistic regression was used to identify predictors of mortality. Among the 26,357 patients with femoral shaft fractures, modified CCIs gradually increased with increasing age category and ISS decreased. Motor vehicle accidents were the most common MOI in the younger 2 age groups, whereas falls were the most common MOI in the 65 years and older age group. The top 3 associated bony injuries for the study cohort as a whole were tibia/fibula (20.5%), ribs/sternum (19.1%), and non-shaft femur (18.9%, of which 5.8% of the total cohort were femoral neck) fractures. The top 3 associated internal organ injuries were lung (18.9%), intracranial (13.5%), and liver (6.2%), injuries. A multivariate mortality analysis showed that increasing age, increasing comorbidity burden, and associated injuries all had independent associations with mortality. The injuries most associated with mortality were thoracic organ injuries (adjusted odds ratio [AOR]=3.53), head injuries (AOR=2.93), abdominal organ injuries (AOR=2.78), and pelvic fractures (AOR=1.80). This study used a large, nationwide sample of trauma patients to profile injuries associated with femoral shaft fractures. Associations between injuries and mortality underscore the importance of these findings. [Orthopedics. 2017; 40(3):e506-e512.].

Novel Spiked-Washer Repair Is Biomechanically Superior to Suture and Bone Tunnels for Arcuate Fracture Repair

OBJECTIVES

Injuries to the posterolateral corner of the knee can lead to chronic degenerative changes, external rotation instability, and varus instability if not repaired adequately. A proximal fibula avulsion fracture, referred to as an arcuate fracture, has been described in the literature, but a definitive repair technique has yet to be described. The objective of this study was to present a novel arcuate fracture repair technique, using a spiked-washer with an intramedullary screw, and to compare its biomechanical integrity to a previously described suture and bone tunnel method.

METHODS

Ten fresh-frozen cadaveric knees underwent a proximal fibula osteotomy to simulate a proximal fibula avulsion fracture. The lateral knee capsule and posterior cruciate ligament were also sectioned to create maximal varus instability. Five fibulas were repaired using a novel spiked-washer technique and the other 5 were repaired using the suture and bone tunnel method. The repaired knees were subjected to a monotonic varus load using a mechanical testing system instrument until failure of the repair or associated posterolateral corner structures.

RESULTS

Compared with the suture repair group, the spiked-washer repair group demonstrated a 100% increase in stiffness, 100% increase in yield, 110% increase in failure force, and 108% increase in energy to failure.

CONCLUSIONS

The spiked-washer technique offers superior quasi-static biomechanical performance compared with suture repair with bone tunnels for arcuate fractures of the proximal fibula. Further clinical investigation of this technique is warranted and the results of this testing may lead to improved outcomes and patient satisfaction for proximal fibula avulsion fractures.

Segond fracture: an MR evaluation of 146 patients with emphasis on the avulsed bone fragment and what attaches to it

OBJECTIVE

To re-evaluate the Segond fragment emphasizing those structures that attach to the fragment in patients with reported acute/subacute anterior cruciate ligament (ACL) injuries, and to clarify the nomenclature used to describe these structures.

MATERIALS AND METHODS

A search of databases of knee MR examinations over 4.5 years with reported ACL tears yielded 19,726 studies. Using strict exclusion criteria, a total of 146 MR studies with acute/subacute ACL tears were re-assessed with respect to the Segond fragment's size, shape, orientation, location, displacement, attaching soft tissue structures, and associated osseous and/or soft tissue injuries.

RESULTS

Segond fractures were present in 1.25 % of reported acute/subacute ACL tears. The fragment measured 11.9 × 7.3 × 3.27 mm, being thin, ovoid, vertically oriented, situated anterolaterally along the proximal tibial epiphysis, posterior to Gerdy's tubercle and inferior to the lateral tibial plateau, and displaced up to 6 mm laterally. The attached structures were the meniscotibial component of the mid-third lateral capsular ligament (mt-MTLCL) in 58.9 %, both the mt-MTLCL and the posterior fibers of the ITB (pf-ITB) in 35.6 %, and the pf-ITB in 5.48 % of cases. In no case was there an additional attaching structure that did not meet criteria for the mt-MTLCL or the pf-ITB.

CONCLUSION

The mt-MTLCL most commonly attaches to the Segond fragment, but the pf-ITB can also attach to this fragment. In no case was there an additional attaching structure that did not meet criteria for the mt-MTLCL or the pf-ITB.