Saudi Journal of Sports Medicine

: 2019  |  Volume : 19  |  Issue : 2  |  Page : 62--65

Surgical treatment of chondral defect of patella associated with patellar subluxation

Naif Mohammed Alhamam1, Ronald A. Dimentberg2, Ahmed Khalid Almulhim3, Omar Abdullaziz Alanzi4,  
1 Department of Orthopedic, Medical College, King Faisal University, Hofuf, Saudi Arabia
2 Department of Orthopedic Surgery, Harvard University, Cambridge, Massachusetts, USA
3 Orthopedic Surgery Resident, King Fahad Hofuf Hospital, Hofuf, Saudi Arabia
4 Otolaryngology Head and Neck Surgery Resident, King Fahad Specialist Hospital, Dammam, Saudi Arabia

Correspondence Address:
Dr. Ahmed Khalid Almulhim
College of Medicine, King Faisal University, Hofuf, Eastern Region
Saudi Arabia


We present the case of a 49-year-old patient brought to the hospital with sudden onset of pain and swelling after falling down on a flexed knee while playing football. In the history review, the patient denied any patellar dislocation, previous injury, and surgical interventions. Examination revealed a grossly swollen knee anteriorly, with tenderness and moderate-to-severe effusion. Magnetic resonance images showed injury to the medial patellofemoral ligament and loose cartilage fragments, which is a rare occurrence without patellar dislocation. Surgery was done 5-day postinjury. To prevent the future complication of the injury, the patient underwent open reduction and internal fixation of the osteochondral fragment with 3.0-mm cannulated screw. After a year, the patient underwent the removal of screw and diagnostic arthroscopy, which portrayed that the patella cartilage had healed. The patient return to playing football 9 months after the surgery.

How to cite this article:
Alhamam NM, Dimentberg RA, Almulhim AK, Alanzi OA. Surgical treatment of chondral defect of patella associated with patellar subluxation.Saudi J Sports Med 2019;19:62-65

How to cite this URL:
Alhamam NM, Dimentberg RA, Almulhim AK, Alanzi OA. Surgical treatment of chondral defect of patella associated with patellar subluxation. Saudi J Sports Med [serial online] 2019 [cited 2021 Oct 24 ];19:62-65
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Patellar chondral defect is a common injury associated with patellar dislocation, and it rarely happens without patellar dislocation or subluxation. Initially, it may be undetected when there is a spontaneous reduction of the patella unless there are manifestations of hemarthrosis, medial or lateral tenderness, or locking due to a loose body in the joint.[1] The mechanism of the injury occurs when there is flexion and external rotation in a valgus position causing the patella to slide posteriorly to the surface of the femoral condyle. As a result, there is a shearing force of the posterior part of the patella (chondral) due to the femoral condyle, which is more stable compared to the patella in this situation.[2] Treatment options vary according to the extent of the injury, but usually, if the osteochondral fragment big enough, fixation is the best option.

The available treatment options depends on the severity and the size of the defect as if the injury involve the chondral part only so the best method of treatment is arthroscopic debridement only, but if the injury became an osteochondral defect the autograft or allograft will be used, and in less sever cases we might go with the chondrocyte implantation.[3]

In rare cases of the isolated chondral defect without patellar dislocation as our case, or resulting from multiple microtrauma of the knee, it is difficult to diagnose the chondral defect due to vague symptoms and negative findings on examination and radiographs, but it is important to diagnose the injury early to avoid cartilaginous defect and early-onset arthritis. As such, there is great importance regarding taking proper detailed history, physical examination, and proper investigation.

 Case Report

A 49-year-old male presented to the emergency department with sudden onset of pain and swelling after falling down with a flexed right knee while playing football. The patient was unable to walk when brought to the hospital. The patient denied any patellar dislocation.

Examination revealed a grossly swollen anterior knee with tenderness and moderate-to-severe effusion. The range of motion was limited and very painful, but there was no crepitus.

The patient denied the past history of previous injury or surgical intervention to the knee. The neurovascular examination was normal. A magnetic resonance image (MRI) showed injury and loose cartilage fragments [Figure 1] and [Figure 2].{Figure 1}{Figure 2}

Surgery was performed 5-day postinjury. After conduction a time out and confirming the site of operation under spinal anesthesia, tourniquet was applied, the patient underwent a diagnostic knee arthroscopy in a supine position through the lateral and anteromedial portals which show chondral loose body about 21 mm from the inferior pole of the patella [Figure 3] and [Figure 4]. Followed by an open reduction and internal fixation of the osteochondral fragment through midline skin incision (3 cm), medial parapatellar approach, the patella was flipped laterally, cleaning of the bed of the chondral fragment reaching to the vascularized surface, then placement of the fragment in the defect area and fixed with (22 mm) cannulated screw (the Herbert screw) long protruding through the anterior cortex to facilitate removal later without arthrotomy [Figure 5] and [Figure 6]. Before closure, the medial patellofemoral ligament was repaired with transosseous suture and medial application, the closure was by layers using Vicryl sutures and prolene for the skin incision. Knee arthroscopy was done again for checking for the placement of the fragment, which was in the proper position.{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Postoperatively, X-rays were taken for confirming the site of the screws [Figure 7] and [Figure 8], the patient was on protective weight-bearing with a knee immobilizer for 6 weeks. Rehabilitation was initiated with isometric exercises during the period of immobilization. After the initial 6 weeks, the patient began exercises to increase the range of motion of the knee for 3 months.{Figure 7}{Figure 8}

The patient was followed up in the clinic, and radiographs were obtained to show proper fixation in situ [Figure 7] and [Figure 8].

Clinically, the patient was evaluated with a modified Lysholm system. The patient received a mean score of 93 in that system, which is considered excellent.

One year later, the patient underwent removal of the screw and diagnostic arthroscopy, which showed healed patellar cartilage [Figure 9]. The patient returns to play football 9 months after the surgery.{Figure 9}


Chondral and osteochondral patellar defects mostly occur with acute dislocation of the patella, and rarely happen without dislocation. In cases of lateral patella dislocation, Nomura et al. found that there are associated patellar joint injuries in up to 95% of the cases, whereas Nietosvaara et al. found an incidence of 39%.[4],[5] According to Nomura, lateral dislocations may contribute to chondral and osteochondral lesions (19%), fractures of the patella (24%), or both (57%).[4] In our case, there was an isolated chondral lesion, which is the least likely scenario with patellar dislocation injuries.

Undiagnosed or untreated chondral or osteochondral patellar defects could cause permanent damage and may lead to the development of rounded and fibrous surfaces and early onset arthritis. As such, early detection and surgical repair have an excellent outcome after the injury.

Definitely, the outcome of the injury would be affected by the size, site, magnitude, and the time frame of the injury.[6]

Patellar dislocation should be suspected given any particular injury, even if there is a relocation of the patella without any clinical signs. For this reason, we advise to obtain an MRI to fully understand the status of the articular surfaces in the knee. However, the role of the MRI is uncertain when compared to arthroscopic examination, according to Sallay et al. and Kirsch et al.[7],[8]

Therefore, given a negative imaging result and positive clinical manifestation, it may be beneficial to do arthroscopic examination to detect the injury. The arthroscopic examination can provide more specific results in the detection of the defect, and it can clarify plans for rehabilitation according to the case needs.

In arthroscopy, we have various materials available to fixate the chondral defect after the debridement, such as using k-wires, bioabsorbable suturing, or cannulated metal screw. Each material has its own advantages and uses.

Hinton and Sharma recommended early exercise with appropriate guidance, depending on the patient's level of pain and state of injury after the operation.[9] Early exercise contributes to a better prognosis, reduces the extent of atrophy of the quadriceps muscle, and keeps the joint healthier.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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