Concurrent Undisplaced Patellar Fracture and Posterior Cruciate Ligament Avulsion Fracture Managed With Surgical Fixation and Rehabilitation: A Case Report

Abstract

This case report explains the successful management of a rare, combined an undisplaced patellar fracture and a posterior cruciate ligament (PCL) avulsion fracture at the tibial attachment in a 44-year-old male patient following a motorbike accident. While both injuries are frequently seen in orthopedic practice, their concurrent occurrence is uncommon. The patient presented with significant knee swelling, limited range of motion, and pain following the accident. An X-ray revealed a patellar fracture and magnetic resonance imaging (MRI) confirmed an undisplaced fracture, a PCL tear, and a medial meniscus injury. The patient underwent surgical intervention for PCL fixation with a cannulated cancellous (CC) screw under spinal anesthesia. Following surgery, a comprehensive rehabilitation program was implemented, focusing on pain management, reducing swelling, regaining range of motion, and strengthening the surrounding musculature. The program progressed through three phases, steadily increasing the intensity and complexity of exercises. The patient exhibited significant improvement in pain, swelling, range of motion, and muscle strength throughout the rehabilitation program. By week 12, he had achieved near-normal knee function and was able to resume most daily activities.

Introduction

Lower limbs are the most vulnerable anatomical area in trauma patients, sustaining injuries in around 19% of cases. Upper limbs are marginally less affected, with a prevalence of approximately 17.7% [1]. High-impact trauma frequently leads to complex injuries, potentially including isolated or multiple ligament tears in the knee [2]. The patella, the largest sesamoid bone in humans, plays a significant role in the extensor apparatus and articulates with the femur in the patellofemoral joint. The primary function of the patella is to serve as a bridge [3]. Fractures of the patella are frequently seen in orthopedic practice and are extensively documented in the medical literature [4].

The posterior cruciate ligament (PCL) stands out as the most robust ligament within the knee, with injuries being less prevalent compared to those of the anterior cruciate ligament (ACL) [5]. The primary role of the PCL is to prevent excessive backward movement of the tibia toward the femur. The PCL consists of two distinct bundles that work together cooperatively, offering both rotational stability and additional reinforcement. These bundles, known as the anterolateral (AL) and posteromedial (PM) bundles, have different orientations within the knee joint. The AL bundle is present more vertically, while the PM bundle is positioned differently. During different degrees of knee flexion, each bundle plays a specific role; the PM bundle primarily restrains posterior translation during moderate flexion, whereas the AL bundle becomes more active during extension and deeper flexion [6]. PCL avulsion fractures, a distinct subtype of PCL injury, are less frequent than the more common intrasubstance tears of the ligament [7]. The occurrence of both a patellar fracture and an avulsion fracture at the tibial attachment of the PCL is rarely documented in existing literature. Hooper et al. reported that 16.8% of PCL avulsion fractures were associated with meniscal injuries, while 19.1% involved additional ligament injuries. Also, patellar fractures commonly lead to anterior knee pain, which can obscure the diagnosis of a concomitant PCL injury by complicating the performance of the posterior drawer test. Furthermore, avulsion fractures at the tibial attachment of the PCL are frequent occurrences in the practice of orthopedic surgery [8]. However, there is scarce literature about meniscus injuries with PCL ligaments [9].

Fractures of the patella can stem from either direct or indirect causes. An example of the classic indirect mechanism is when someone falls on their feet, prompting the quadriceps to eccentrically contract in an attempt to slow down the body's descent. If the force of the fall surpasses the knee's ability to resist flexion, the extensor mechanism may fail, resulting in a patellar fracture. Similarly, avulsion fractures of the PCL at its tibial insertion often occur due to a specific event known as a dashboard injury. This happens when the knee is in a flexed position, and something hits it directly from the anterior side. The combination of knee flexion and a posteriorly directed force applied to the pretibial area can lead to an avulsion fracture of the PCL at its attachment point on the tibia [10,11]. Failure to address these injuries appropriately can result in a range of complications, including persistent laxity in the posterior knee, loss of motion, ongoing knee pain, fractures, osteonecrosis, compartment syndrome, and the development of heterotopic ossification. Neurovascular injuries such as a popliteal artery, common peroneal nerve, and tibial nerve injuries can also be seen in PCL avulsions [12]. This case report describes a surgical solution for knee joint instability. The procedure involves fixing the PCL with a cannulated cancellous (CC) screw [13]. Following surgery, a tailored rehabilitation program is implemented to guide the patient's recovery in stages [14].

Case presentation

Patient information

A 44-year-old male patient presented with significant knee swelling and limited range of motion following a road traffic accident on January 7, 2024. The accident occurred while he was traveling on a motorcycle to his hometown when he encountered the sudden appearance of a truck from the opposite direction. To avoid a collision, he swerved, resulting in a crash with a divider. Although he fell with his knee flexed, he remained conscious without any bleeding from the ear, nose, or throat, nor did he experience nausea or vomiting. Upon initial assessment at a nearby hospital, an X-ray conducted on January 8, 2024, revealed a patellar fracture, causing severe pain and swelling in his right knee, especially during knee flexion. Subsequently, he was referred to our hospital for further evaluation, where a magnetic resonance imaging (MRI) on January 10, 2024, revealed a minimally displaced patellar fracture, a tear in the PCL, and injury to the posterior horn of the medial meniscus. Until January 15, 2024, conservative management with a long plaster cast was implemented. On January 17, 2024, the patient underwent surgical intervention for PCL fixation with a 4.5 mm CC screw under spinal anesthesia.

Clinical examination

Before the examination began, we obtained the patient's informed consent for the procedure and explained the possibility of publishing their case as a report. The patient was alert and cooperative and demonstrated full orientation to their surroundings, including time, location, and personal identity. The patient was seen supine, lying with the right leg elevated with the help of a long pillow. A patellar tendon-bearing cast was present to manage the patellar fracture conservatively. This assessment was taken before his surgery; on observation, the patient exhibited a mesomorphic physique with no signs of edema or muscle atrophy. The patient's present pain magnitude was measured with a visual analog scale (VAS) of 7.5 which indicates severe pain at the knee joint during palpation; the patient displayed grade 4 tenderness in specific areas, including the medial aspect of the right thigh. The skin was noted to be dry, with swelling evident over the right thigh and medial aspect of the distal thigh and around the popliteal fossa of the right lower limb. The skin was noted to be dry, with swelling evident over the right thigh and medial aspect. On examination, his ranges were taken with the help of a goniometer, and manual muscle testing was done.

Table 1 depicts the timeline of events for the patient.

Investigations

Before undergoing surgery, the patient underwent several investigations to assess their overall health status and evaluate the extent of knee injuries. These investigations included a complete blood count (CBC), kidney function test (KFT), and liver function test (LFT), all of which returned within normal ranges, indicating no underlying systemic abnormalities.

Furthermore, pre-operative imaging studies were conducted to precisely assess the extent of knee injuries. The X-ray revealed a non-comminuted transverse patellar fracture, indicating a fracture across the patella without fragmentation. Additionally, the pre-operative MRI provided detailed insights, revealing a complete tear of the PCL, a grade 2 tear of the posterior horn of the medial meniscus, and an undisplaced fracture of the patella. These diagnostic findings were crucial in guiding the surgical approach and planning the appropriate interventions to address the identified injuries comprehensively.

In Figure 1, a recent MRI analysis of the knee shows a PCL injury accompanied by bone marrow edema. The joint space and cartilage appeared normal, and there were evident meniscal tears.

Surgery details

On the surgical table, the patient was placed in a prone posture with precautionary padding to shield bone prominences. The skin was carefully incised into a 5 cm S shape, and the muscles between the gastrocnemius and semimembranosus were then carefully dissected apart. The next procedure was a vertical capsular incision. Evaluation of the best fixing technique was made possible by the identification of skeletal pieces. In order to secure the fracture reduction, two Kirschner wires were inserted into the tibia. A 4.5-mm CC screw was placed along the posterior portion of the tibial intercondylar eminence to complete the stabilization once reduction was verified. Using C-arm imaging, the appropriate decrease was confirmed. The surgical wound was carefully sutured shut after it had been well-irrigated. After a smooth and effective surgery, the patient was moved to the intensive care unit for recovery.

Figures 2, 3 show a postoperative X-ray of the right knee showing PCL avulsion fixation in the lateral and anteroposterior (AP).

Diagnostic assessment

On postoperative day one, following knee surgery, patients typically experience severe pain, with VAS scores ranging around 7.8 and noticeable swelling around the knee. Initial assessments focus on measuring the range of motion (ROM) in knee flexion and extension, which is often limited due to pain and swelling, and evaluating muscle strength through manual muscle testing (MMT), which typically shows reduced strength. MMT for the hip in the pre-operative state, for the hip and knee was assessed in a side-lying position, and for the ankle in the prone position. MMT in the postoperative state is checked in sitting and side-lying for the hip, prone for the knee, and standing for the ankle. Functional outcome measures involve the knee injury and osteoarthritis outcome score (KOOS), assessing pain, symptoms, daily living activities, sports function, and quality of life; the timed up and test (TUG), evaluating basic functional mobility and balance; and the lower extremity functional scale (LEFS), determining the patient's ability to perform everyday tasks. These evaluations establish a baseline for guiding the initial stages of rehabilitation and monitoring recovery progress. Table 2 presents the active ROM measurements.

Table 3 details the manual muscle testing (MMT) scores for the same joints and movements across the same time points.

Physiotherapeutic intervention

After PCL avulsion, potential complications like knee hyperextension and tibial translation necessitate early post-surgery physiotherapy. The treatment targets swelling, joint effusion, knee pain, and limited motion. Weekly rehabilitation progresses from managing swelling to restoring motion and strength. Cryotherapy, compression, and elevation alleviate initial inflammation. Subsequent weeks focus on regaining full knee extension and flexion through passive and active exercises, emphasizing proper alignment. Strengthening exercises target muscles around the knee, starting with isometrics and advancing to dynamic exercises. Pain monitoring and exercise progression prevent overexertion. Manual therapy may address residual stiffness. This tailored rehabilitation approach minimizes complications and promotes joint function, strength, and stability post-PCL reconstruction and open reduction internal fixation (ORIF) with a locked patella nail for the patella.

This protocol is made with a combination of different exercises and protocols taken from therapeutic exercise foundations and techniques by Kisner, Carolyn, and Colby [15] and Massachusetts General Brigham Sports Medicine [16]. The physiotherapy intervention protocol with rationale and description is mentioned in Tables 4-6.

Patient performing physiotherapy exercise in phase 1, shown in Figure 4.

Outcome measures

To assess your knee injury's impact on daily life, the outcome measures used are the KOOS questionnaire for pain, symptoms, activities, and quality of life; the TUG test to gauge basic mobility and balance; and the LEFS to evaluate your ability to perform tasks in your activities of daily living. For pain, the VAS is used. The interpretation of the values is given in Table 7.

Discussion

This case report outlines a comprehensive rehabilitation program, meticulously divided into distinct phases. This program prioritizes complete patient recovery, minimizes the risk of future complications, and allows a seamless return to their usual activities. By focusing on these objectives, the program aims to optimize the patient's long-term health and well-being. A male aged 44 years sustained a complex knee injury following a motorbike accident, resulting in a minimally displaced patellar fracture, a complete tear of the PCL, and a grade 2 tear of the posterior horn of the medial meniscus. The combination of a patellar fracture and a PCL avulsion fracture is notably rare, emphasizing the need to consider a wide range of potential injuries during the initial evaluation of knee trauma, particularly in high-impact scenarios [17]. Patellar fractures can obscure a concomitant PCL injury by complicating the performance of a posterior drawer test, making diagnostic imaging like MRI crucial for confirming the extent of ligament damage. The surgical intervention involved ORIF with a CC screw, a well-established method that provides stability and supports the healing of the PCL. After a comprehensive review of a case series by Rasmussen RG et al., the study demonstrates that patients with acute PCL injuries, treated with physiotherapy-led exercise and support brace intervention, experienced significant improvements in patient-reported outcomes and knee flexion strength over two years [18]. Also, according to Triska Monitari et al., exercise therapy post-acute PCL reconstruction offers benefits like maintaining patellar mobility, quadriceps muscle tone, full passive extension, pain and edema control, and early knee joint mobilization. Active movement training improves the range of motion and muscle elasticity and reduces pain, promoting peripheral circulation in the lower limbs. A structured and progressive rehabilitation program is essential for optimizing outcomes following PCL reconstruction and patellar fracture fixation. The rehabilitation protocol outlined in the case report focused on several key components, including pain management, swelling reduction, ROM restoration, muscle strengthening, neuromuscular control, and functional activities. To initiate early mobility, physiotherapy interventions, such as cryotherapy, ankle pumping exercises, and voluntary muscle activation, were employed to promote tissue healing and prevent joint stiffness. Additionally, a gradual progression of weight-bearing activities, balance exercises, proprioceptive drills, and cardiovascular conditioning was incorporated to enhance muscle strength, joint stability, and overall functional capacity [19].

The rehabilitation program led to favorable outcomes, as evidenced by the improvement in outcome measures over time. The patient experienced significant reductions in pain intensity, joint effusion, and functional impairment, with restored knee mobility, muscle strength, and stability [20]. The absence of knee pain, joint effusion, and instability indicated successful tissue healing, optimal joint function, and satisfactory recovery postoperatively. In conclusion, the comprehensive management approach described in these case reports underscores the importance of accurate diagnosis, appropriate surgical intervention, and structured rehabilitation in achieving favorable outcomes for patients with complex knee injuries involving patellar fractures and PCL tears. By addressing the unique challenges associated with each injury component and implementing a multidisciplinary treatment strategy, clinicians can optimize patient recovery and restore functional independence effectively.

While the case report demonstrates success, its generalizability might be limited due to the single-patient focus. Future studies with larger cohorts could validate the program's effectiveness and identify potential modifications for a broader application. Additionally, future research should focus on optimizing diagnosis, surgical techniques, rehabilitation protocols, and long-term outcomes for this specific fracture-ligament combination. This comprehensive approach, encompassing multiple phases of rehabilitation, aims to facilitate the patient's return to normal activities, minimize the risk of recurrent instability, and optimize long-term outcomes.

Conclusions

This case report showcases the effective management of a rare combination of an undisplaced patellar fracture and a PCL avulsion fracture at the tibial attachment in a 44-year-old male patient. Successful treatment involved precise surgical fixation with a CC screw and a phased rehabilitation program. By week 12, the patient achieved significant improvements in pain, swelling, range of motion, and muscle strength, regaining near-normal knee function. This case emphasizes the importance of accurate diagnosis, appropriate surgical intervention, and individualized rehabilitation in managing complex knee injuries, highlighting the potential for excellent outcomes through tailored, holistic care.