Combined posterolateral corner and acute anterior cruciate ligament injuries in an adolescent cohort: a magnetic resonance imaging analysis

Combined posterolateral knee reconstruction: ACL-based injuries perform better compared to PCL-based injuries

PURPOSE

To compare post-operative physical activity and return to work after combined posterolateral corner (PLC) reconstruction (PLC-R) in anterior cruciate ligament (ACL)- or posterior cruciate ligament (PCL)-based injuries.

METHODS

Patients aged > 18 years undergoing PLC-R using the Larson technique combined with either ACL or PCL reconstruction were included. Outcome was evaluated retrospectively after a minimum follow-up of 24 months using Tegner Activity Scale, Activity Rating Scale (ARS), Knee Injury and Osteoarthritis Outcome Score (KOOS), work intensity according to REFA classification, and a questionnaire about type of occupation and time to return to work.

RESULTS

A total of 32 patients (11 ACL-based injuries and 21 PCL-based injuries) were included. Mean follow-up was 56 ± 26 months in the ACL-based injury group and 59 ± 24 months in the PCL-based injury group. All patients in the ACL-based injury group and 91% of patients in the PCL-based injury group returned to sports activities. Comparing pre- and post-operative values, a significant deterioration of the Tegner Activity Scale and ARS was observed in the PCL-based injury group, whereas no significant change was observed in the ACL-based injury group. KOOS subscales were generally higher in the ACL-based injury with significant differences in the subscale sports and recreational activities. Patients with ACL-based injuries returned to work significantly earlier compared to patients with PCL-based injuries (11 ± 4 weeks vs. 21 ± 10 weeks, p < 0.05).

CONCLUSION

High rates of return to sports and work can be expected after combined PLC-R in both ACL- and PCL-based injuries. However, deterioration of sports ability must be expected in PCL-based injuries. ACL-based injuries led to superior patient-reported outcomes and an earlier return to work, as compared to PCL-based injuries.

LEVEL OF EVIDENCE

Level IV.

Concomitant Posterolateral Corner Injuries in Skeletally Immature Patients With Acute Anterior Cruciate Ligament Injuries

BACKGROUND

Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients.

METHODS

Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist.

RESULTS

A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19).

CONCLUSIONS

Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

Types of posterolateral corner injury associated with both bundle and selective-bundle ACL tears

BACKGROUND

It is unknown whether a selective-bundle tear of the anterior cruciate ligament (ACL) shows a different prevalence of posterolateral corner (PLC) injury than a both-bundle tear.

PURPOSE

The prevalence of injury of PLC stabilizer in relation to the type of combined ACL tear (both-bundle and selective-bundle tears) has been investigated.

MATERIAL AND METHODS

This retrospective study included 94 patients who were diagnosed with an ACL tear after knee joint magnetic resonance imaging and underwent arthroscopic surgery. We compared the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear. We used Fischer exact tests to compare the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear.

RESULTS

Both-bundle tears occurred in 55 cases (56%) and selective-bundle tears in 39 cases (44%). The most common PLC injury with an ACL tear was inferior popliteomeniscal fascicle (PMF) injury, followed by superior PMF injury. The prevalence of each PLC injury was higher for both-bundle tears than selective-bundle tears, with the exception of popliteus tendon injury diagnosed by reader 1 (P.H.J). However, these differences were statistically significant for superior PMF injury only ( p < 0.05). The prevalence of PLC injury was unrelated to the type of selective-bundle tear (anteromedial vs posterolateral).

CONCLUSION

Superior PMF injury is more common in both-bundle tears than selective-bundle tears. There is no statistically significant difference in the prevalence of PLC injury between both-bundle tears and selective-bundle tears.

Fast-tracked Rehabilitation and Return to Sport of an Elite Rugby Player with a Complicated Posterolateral Corner Injury and Associated Peroneal Paralysis

Acute posterolateral corner injuries of the knee with associated hamstring avulsions and peroneal paralysis are rare in rugby. Regain of motor function following a complete paralysis is documented to be 38%. To our knowledge, only one case describes return to preinjury level of competitive sport taking up to 27 months. A 24-year-old international level rugby player, a medical student, sustained an acute posterolateral knee injury with associated anterior cruciate ligament tear, bicep femoris and semimembranosus avulsions as well as a complete peroneal paralysis. The patient returned to full-time medical rotation work weeks at 5 months. At 10 months, the patient was considered to have returned to preinjury level of activity having managed a 5 km run, participated regularly in non-contact rugby and performed exercises at 140% of his preinjury maximum. This case report describes the successful outcome of a high-frequency high-intensity rehabilitation.

Incidence and MRI characterization of the spectrum of posterolateral corner injuries occurring in association with ACL rupture

OBJECTIVE

To determine the incidence and MRI characteristics of the spectrum of posterolateral corner (PLC) injuries occurring in association with anterior cruciate ligament (ACL) rupture.

MATERIALS AND METHODS

We carried out a level IV, retrospective case series study. All patients clinically diagnosed with an ACL rupture between July 2015 and June 2016 who underwent MRI of the knee were included in the study. In addition to standard MRI knee reporting, emphasis was placed on identifying injury to the PLC and a description of involvement of these structures by two musculoskeletal radiologists. Association with PLC involvement was sought with concomitant injuries using correlation analysis and logistic regression.

RESULTS

One hundred sixty-two patients with MRI following ACL rupture were evaluated. Thirty-two patients (19.7%) had an injury to at least one structure of the PLC, including the inferior popliteomeniscal fascicle (n = 28), arcuate ligament (n = 20), popliteus tendon (n = 20), superior popliteomeniscal fascicle (n = 18), lateral collateral ligament (n = 8), popliteofibular ligament (n = 7), biceps tendon (n = 4), iliotibial band (n = 3), and fabellofibular ligament (n = 1). Seventy-five percent of all patients with combined ACL and PLC injuries had bone contusions involving the lateral compartment of the knee. The presence of these contusions strongly correlated with superior popliteomeniscal fascicle lesions (p < 0.05). There was no correlation between injuries to other structures of the PLC and other intra-articular lesions.

CONCLUSION

Missed injuries of the PLC lead to considerable morbidity. The relevance of this study is to highlight that these injuries occur more frequently than previously described and that an appropriate index of suspicion, clinical examination, and MRI are all required to reduce the risk of missed diagnoses. The results of this study support previous suggestions that the rate of concomitant PLC injury in the ACL-deficient knee is under-reported. The rate of combined injuries in this series was 19.7%. The key message of this paper is that PLC injury is common in the presence of ACL injury and should be sought both clinically and radiologically.

Dial Test: Unrecognized Predictor of Anterior Cruciate Ligament Deficiency

PURPOSE

To evaluate the effect of isolated anterior cruciate ligament (ACL) injury on tibial external rotation as measured by the dial test.

METHODS

Twenty-seven consecutive patients scheduled to undergo a primary ACL reconstruction were prospectively evaluated. Physical examination and magnetic resonance imaging findings were analyzed to exclude multiligamentous injury. The dial test was performed with the patient under anesthesia with a goniometer on both the affected and unaffected knees at 30° and 90°. Intraoperatively, the arthroscopic posterolateral corner gaps before reconstruction and after reconstruction were documented. Postoperatively, the dial test was again performed on both knees at 30° and 90°.

RESULTS

At 30°, there was a significantly larger dial test result in the affected knee before ACL reconstruction compared with after ACL reconstruction (27.6° vs 21.0°, P < .0001) and compared with the unaffected knee (27.6° vs 20.5°, P < .0001), but this difference was eliminated after reconstruction (21.0° vs 20.5°, P = .5089). At 90°, there was a significantly larger dial test result in the affected knee before ACL reconstruction compared with after ACL reconstruction (27.6° vs 21.1°, P < .0001) and compared with the unaffected knee (27.6° vs 20.9°, P < .0001), with this difference was eliminated after reconstruction (21.1° vs 20.9°, P = .7831).

CONCLUSIONS

Incompetence of the ACL accounts for nearly 7° of tibial external rotation found by the dial test. During examination of an injured knee, if the dial test is positive, an isolated ACL injury should not be excluded. Findings of the dial test should thus be interpreted with caution in the setting of ACL injury.

LEVEL OF EVIDENCE

Level II, prospective comparative study.