
==== Front
Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00721-0
10.1016/j.radcr.2024.07.133
Case Report
Isolated proximal tibiofibular dislocation: Don't miss it
Bouya Ayoub bouya.ayoub5@gmail.com
ad⁎
Faraj Chaymae bd
Bouya Rachad cd
En-Nouali Hassan bd
Zidouh Saad cd
Bouabid Salim ad
a Orthopedic Service; Mohammed V Military Instruction Hospital; Rabat; Morocco
b Radiology Service; Mohammed V Military Instruction Hospital; Rabat; Morocco
c Emergency Service; Mohammed V Military Instruction Hospital; Rabat; Morocco
d Mohammed V University of Rabat; Morocco
⁎ Corresponding author. bouya.ayoub5@gmail.com
23 8 2024
11 2024
23 8 2024
19 11 51825186
12 7 2024
22 7 2024
23 7 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Proximal tibiofibular joint (PTFJ) dislocation is a rare but significant traumatic knee injury that often goes undetected due to its subtle presentation and the rarity of the condition. It accounts for less than 1% of all knee injuries, making it an uncommon diagnosis in clinical practice. Despite its rarity, the implications of missing this injury can be profound, leading to chronic pain, instability, and potential nerve damage if not appropriately managed.Effective management, from closed reduction to open reduction, requires awareness from both clinicians and radiologists.

In this case report, we present the clinical presentation, radiological investigations, treatment, and outcome of a 38-year-old woman who presented with a painful left knee following a domestic accident. The diagnosis of anterolateral tibiofibular dislocation was confirmed through careful clinical and radiological assessment. This case underscores the critical importance of early recognition and appropriate management of this uncommon knee injury to prevent long-term complications and ensure optimal patient outcomes.

By detailing this case, we aim to raise awareness among clinicians about the need for vigilance in diagnosing PTFJ dislocations and to highlight the key steps in the diagnostic and therapeutic process. This case report contributes to the growing body of literature on PTFJ dislocations, emphasizing the clinical and radiological cues that should prompt consideration of this diagnosis.

Keywords

Dislocation
Isolated
Emergency
knee
Proximal tibiofibular joint
==== Body
pmcIntroduction

Proximal tibiofibular joint (PTFJ) dislocation is a rare but significant traumatic knee injury that often goes undetected due to its subtle presentation and the rarity of the condition. It accounts for less than 1% of all knee injuries, making it an uncommon diagnosis in clinical practice [1]. Despite its rarity, the implications of missing this injury can be profound, leading to chronic pain, instability, and potential nerve damage if not appropriately managed [2].

Ogden's classification describes 4 types of traumatic proximal tibiofibular joint dislocations. Anterolateral dislocation, the most common type, typically occurs with a mechanism involving knee flexion, internal rotation, and foot plantar flexion [3].

In this case report, we present the clinical presentation, radiological investigations, treatment, and outcome of a 38-year-old woman who presented with a painful left knee following a domestic accident. This case underscores the critical importance of early recognition and appropriate management of this uncommon knee injury to prevent long-term complications and ensure optimal patient outcomes.

By detailing this case, we aim to raise awareness among clinicians and radiologists about the need for vigilance in diagnosing PTFJ dislocations.

Case report

A 38-year-old right-handed housewife with no significant medical history presented to the emergency department with a painful left knee following a domestic accident. She reported slipping on wet ground in her kitchen, causing her left knee to flex and her ankle to internally rotate. The pain was severe, rated as 8/10 on the pain scale, and she was unable to bear weight on the affected leg.

Physical examination revealed lameness and lateral swelling of the left knee without joint effusion. Palpation of the fibular head was painful, but there was no instability. The range of motion was limited to 10° of passive extension and 100° of passive flexion. Examination of the fibular nerve showed no abnormalities.

Given the patient's history and physical findings, initial X-rays of both knees were obtained, which indicated a dislocation of the proximal tibiofibular joint (Fig. 1). There were no other injuries detected. A CT scan was subsequently performed to confirm the anterolateral tibiofibular dislocation (Fig. 2), ensuring accurate diagnosis and planning for treatment.Fig. 1 X-rays of both knees showing anterolateral PFTJ dislocation.

Fig 1:

Fig. 2 CT reconstruction images of the PFTJ dislocation. (A) anterior displacement. (B) lateral displacement.

Fig 2:

The medical team opted for closed reduction to treat the dislocation. Within 2 hours of admission and under moderate anesthesia, an orthopedist applied gentle pressure on the fibular head in the anterior-to-posterior direction. During the manipulation, an assistant maintained the left knee in a flexed position and the ankle in plantar flexion. The reduction was confirmed by follow-up X-rays (Fig. 3).Fig. 3 X-rays after closed reduction.

Fig 3:

Postreduction treatment included immobilization with a knee brace for 1 week to ensure stability and healing. The patient was instructed on partial weight-bearing initially, progressing to full weight-bearing as tolerated. A rehabilitation program consisting of gentle range-of-motion exercises and gradual strengthening was prescribed.

At the 3-month follow-up, the patient reported complete resolution of pain and had regained full function of her left knee. She was able to resume all normal activities without limitations. Follow-up assessments showed no signs of instability or nerve damage, and the patient demonstrated full range of motion and strength in the affected knee.

Discussion

Proximal tibiofibular joint (PTFJ) dislocation is a rare and often overlooked injury, comprising less than 1% of traumatic knee injuries [4]. This rarity contributes to the diagnostic challenges it presents, as the injury frequently goes undetected [5]. The typical mechanism involves knee flexion greater than 90°, combined with internal rotation and plantar flexion of the foot [1]. Sports injuries are the predominant cause, and the injury is most common in males aged 17-30 years [6,7].

Ogden's classification from 1974 remains a cornerstone in understanding PTFJ dislocations, categorizing them based on the direction of fibular displacement [1,3] (Fig. 4):• Type I (Subluxation or Laxity):○ Mechanism: Often occurs during growth due to minor trauma or stress.

○ Clinical Presentation: Typically self-limiting, with symptoms including mild pain and discomfort. Patients may experience intermittent instability or a sensation of the knee giving way.

• Type II (Anterolateral Dislocation):○ Mechanism: Results from internal rotation and plantar flexion of the foot, combined with external rotation and flexion of the knee.

○ Clinical Presentation: Characterized by acute pain and tenderness over the fibular head, lateral knee swelling, and limited range of motion. This type accounts for 85% of cases.

• Type III (Posteromedial Dislocation):○ Mechanism: Typically caused by a direct blow or trauma to the proximal fibula.

○ Clinical Presentation: Presents with severe pain and tenderness on the lateral aspect of the knee, swelling, and potential neurovascular symptoms due to the proximity to the peroneal nerve.

• Type IV (Superior Dislocation with Fibular Fracture):○ Mechanism: Associated with high-energy trauma resulting in a fibular fracture.

○ Clinical Presentation: Involves intense pain, significant swelling, and deformity. This type often includes a fracture and a higher likelihood of neurovascular compromise.

Fig. 4 Ogden classification of PTFJ dislocation [1,3]. (A) Subluxation: increased movement of proximal fibula head in all directions. (B) Anterolateral: anterior and lateral displacement of proximal fibula head. (C) Posteromedial: posterior and medial displacement of proximal fibula head. (D) Superior: superior displacement of proximal fibula head.

Fig 4:

Regardless of type, PTFJ dislocation may involve peroneal nerve damage, particularly in Types III and IV [8]. Clinically, patients often present with lateral knee pain, lameness, and a widened knee compared to the contralateral side. Palpation of the fibular head is typically painful, but there is usually no joint effusion. The fibular nerve function should be thoroughly examined, and ankle edema should be checked [9].

Diagnostically, PTFJ dislocation can mimic other conditions like partial lateral collateral ligament rupture, meniscal cysts, or lateral meniscal tears, leading to initial misdiagnosis. Standard knee X-rays with anteroposterior and lateral views are crucial for detecting the displacement of the fibular head. Incorrectly positioned X-rays can miss the diagnosis; hence, obtaining bilateral knee X-rays for comparison is recommended [10]. In ambiguous cases, a CT scan provides definitive evidence of the dislocation, while MRI is rarely used but may be considered in specific scenarios, such as in pregnant women or after unsuccessful closed reduction [1].

Treatment strategies range from closed reduction to open reduction with internal fixation (ORIF) [9]. Closed reduction involves applying pressure on the fibular head in the opposite direction of displacement, with the ankle in inversion/plantar flexion [1]. ORIF is reserved for cases where closed reduction fails or when the diagnosis is delayed [11,12]. Postreduction, radiographic confirmation and thorough peroneal nerve examination are essential. The duration of immobilization and weight-bearing status post-treatment lacks consensus and varies depending on individual patient factors [1,11].

Proximal tibiofibular dislocation, though rare, can result in several significant complications if not diagnosed and managed appropriately. Chronic pain is a common complication due to persistent instability or misalignment of the joint, leading to altered biomechanics and subsequent wear on joint surfaces [13]. Joint instability may result in repeated dislocations or subluxations, exacerbating joint damage and leading to chronic discomfort and functional limitations [5]. Peroneal nerve injury, due to its proximity to the fibular head, is particularly susceptible during dislocation or reduction, causing foot drop, sensory deficits, and weakness in the anterior and lateral compartments of the leg; this is more frequent in Type III and IV dislocations [14]. Post-traumatic arthritis can develop from disruption of joint surfaces and cartilage damage during dislocation, resulting in long-term pain, stiffness, and reduced range of motion [11].

Inadequate initial treatment or noncompliance with postreduction care increases the risk of recurrent dislocations, potentially necessitating more invasive interventions such as open reduction and internal fixation (ORIF) [6]. The combination of pain, instability, and restricted motion can lead to significant functional impairment, affecting weight-bearing activities, walking, and sports participation [9]. Delayed diagnosis, due to the injury often being overlooked or misdiagnosed, can prolong pain and disability, highlighting the need for a high index of suspicion and thorough clinical and radiological evaluation in patients with knee injuries [2] . Early and appropriate management is crucial to minimize these complications and optimize outcomes, as evidenced by the successful resolution in our case following prompt intervention.

Comparing our findings with the existing literature, the case aligns with the typical presentation and successful management outcomes of anterolateral PTFJ dislocations. However, continued research and case studies are needed to establish standardized treatment protocols and improve diagnostic accuracy.

Conclusion

Isolated proximal tibiofibular joint dislocation, although rare, is a significant injury that can be easily overlooked. Clinicians should maintain a high index of suspicion for this condition when evaluating patients presenting with knee pain, especially when the mechanism of injury involves knee flexion, internal rotation, and foot plantar flexion. Detailed clinical examination is crucial, with attention to signs such as lateral knee pain, swelling, and tenderness over the fibular head, despite the absence of joint effusion or instability.

Radiologists play a key role in the diagnosis of proximal tibiofibular dislocation. Accurate interpretation of X-rays is essential, and obtaining anteroposterior and lateral views of both knees can help in identifying the displacement of the fibular head. In cases where the diagnosis is unclear or there is clinical suspicion despite normal X-rays, a CT scan should be performed to provide a definitive diagnosis.

Ultimately, increasing awareness among healthcare providers about this uncommon injury can improve diagnostic accuracy and patient outcomes. By considering proximal tibiofibular dislocation in the differential diagnosis of knee injuries and utilizing appropriate imaging techniques, clinicians can ensure timely and effective treatment, minimizing the risk of persistent symptoms and functional impairment.

Patient consent

Written informed consent for the publication of this case report was obtained from the patient.

Consent for publication

The patient declares no conflict of interest in publishing the case report for academic purposes.

Author contributions

Ayoub Bouya, Rachad Bouya, and Chaymae Faraj make substantial contributions to the acquisition of data, conception and design, and analysis and interpretation of data.

Hassan En-Nouali, Saad Zidouh, and Salim Bouabid participated in revising it critically for important intellectual content and gave final approval of the version to be submitted.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments: Nil.
==== Refs
References

1 Cunningham NJ Farebrother N Miles J. Review article: Isolated proximal tibiofibular joint dislocation Emerg Med Australas 31 2 2019 156 162 29671944
2 Kennedy MI Dephillipo NN Moatshe G Buckley PS Bernhardson AS LaPrade RF. Proximal tibiofibular reconstruction in adolescent patients Arthrosc Tech 7 12 2018 e1305 e1e10 30591879
3 Ogden JA. Subluxation and dislocation of the proximal tibiofibular joint J Bone Joint Surg Am 56 1 1974 145 154 4812157
4 Nieuwe Weme RA Somford MP Schepers T. Proximal tibiofibular dislocation: a case report and review of literature Strategies Trauma Limb Reconstr 9 3 2014 185 189 25526858
5 McNamara WJ Matson AP Mickelson DT Moorman CT Surgical management of proximal tibiofibular joint instability using an adjustable loop Cortic Fixat Device. Arthrosc Tech. 7 3 2018 e271 e2e7
6 Burke NG Robinson E Thompson NW. An isolated proximal tibiofibular joint dislocation in a young male playing soccer: a case report Cases J 2 2009 7261 19829940
7 Horst PK LaPrade RF. Anatomic reconstruction of chronic symptomatic anterolateral proximal tibiofibular joint instability Knee Surg Sports Traumatol Arthrosc 18 11 2010 1452 1455 20127312
8 Ogden JA. The anatomy and function of the proximal tibiofibular joint Clin Orthop Relat Res 101 1974 186 191
9 Milankov M Kecojević V Gvozdenović N Obradović M. Dislocation of the proximal tibiofibular joint Med Pregl 66 9-10 2013 387 391 24245447
10 Crothers OD Johnson JT. Isolated acute dislocation of the proximal tibiofibular joint. Case report J Bone Joint Surg Am 55 1 1973 181 183 4691656
11 Mamound A Hoencamp R Bosman WM Leijnen M. Proximal tibiofibular joint dislocation: a rare entity BMJ Case Rep 12 1 2019 e227953
12 Aladin A Lam KS Szypryt EP. The importance of early diagnosis in the management of proximal tibiofibular dislocation: a 9- and 5-year follow-up of a bilateral case Knee 9 3 2002 233 236 12126684
13 Marchetti DC Moatshe G Phelps BM Dahl KD Ferrari MB Chahla J The proximal tibiofibular joint: a biomechanical analysis of the anterior and posterior ligamentous complexes Am J Sports Med 45 8 2017 1888 1892 28339288
14 Grechenig P Hohenberger G Maier M Grechenig C Holweg P Vielgut I The articular branch of the peroneal nerve to the proximal tibiofibular joint descends at a mean height of approximately 18 mm distal to the postero-lateral tip of the fibular head Knee Surg Sports Traumatol Arthrosc 29 4 2021 1232 1237 32691096
