The clinical manifestations and pathomechanics of contracture of the extensor mechanism of the knee

Soft Tissue Lengthening for Flexion Dislocation of Patella

PURPOSE OF REVIEW

Obligatory dislocation of the patella (also known as habitual dislocation) is a rare subset of patellofemoral instability in which the patella dislocates every time the knee is flexed. The problem arises due to contracture of the quadriceps muscles. Soft tissue lengthening procedures such as quadriceps tendon lengthening are the mainstay of treatment, in contrast to medial patellofemoral reconstruction (MPFL-R) for the more common recurrent lateral patellar dislocation. The current review explores the existing literature surrounding the pathophysiology and treatment strategies for this unique cause of knee instability.

RECENT FINDINGS

Flexion dislocation of the knee often presents in children when they begin to walk. It is also termed obligatory or habitual because the patella dislocates laterally with each flexion and extension cycle of the knee. In contrast to other forms of patellar dislocation, the displacement is painless in obligatory dislocation. Likewise, the underlying biomechanical cause of this issue is related to contracture of tissues lateral to the patella rather than disruption of medial soft tissues as seen in recurrent/traumatic dislocation or subluxation of the patella. A number of procedures have been described for management of obligatory dislocation of the patella, with the general consensus that a combination of procedures including release/lengthening of the proximal lateral soft tissues as a critical component for a successful outcome. Soft tissue release/lengthening has been performed for over 50 years to treat obligatory dislocation of the patella. This procedure must be used in combination with other proximal and distal reconstructive with careful intraoperative assessment of knee flexion and patellar tracking for satisfactory outcomes. Further research using standardized outcome measures is needed to identify the optimal step-wise approach in treatment of obligatory patellar dislocation.

Comparison of Habitual Versus Recurrent Patellar Dislocation in Children and Adolescents: Differences in Radiological Features

Background

Recurrent patellar dislocation (RPD) and habitual patellar dislocation (HPD) in flexion are frequently encountered in children and adolescents.

Purpose

To compare the radiological features of RPD and HPD in children and adolescents.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Imaging data were collected from patients aged 9 to 15 years who received surgical treatment for HPD or RPD at a single institution between June 2015 and September 2020. The prevalence of trochlear dysplasia, tibial tubercle lateralization, and lower limb rotational deformity was assessed through hip/knee/ankle computed tomography (CT) using the following quantitative indicators: trochlear depth index, lateral trochlear inclination, sulcus angle, tibial tubercle-trochlear groove (TT-TG) distance, ratio of TT-TG distance to femoral width, TT-TG angle, femoral anteversion angle, and tibial external rotation angle. The morphology of trochlea and patella were graded on knee CT using the Dejour and Wiberg classification. The Insall-Salvati index and Caton-Deschamps index were used to evaluate the height of the patella on lateral view radiographs. To evaluate lower limbs malalignment, the mechanical lateral distal femoral angle and medial proximal tibial angle were measured on weightbearing full-length radiographs. The collected data were analyzed and compared between the HPD and RPD groups.

Results

Enrolled were 15 patients (21 knees) diagnosed with HPD and 18 patients (22 knees) diagnosed with RPD. The age of first dislocation was significantly younger in the HPD group (7.6 ± 3.4 vs 11.2 ± 1.4 years; P = 0.003). Knees in the HPD group had a significantly higher proportion of Dejour type C dysplasia (57.1% vs 4.5%; P < .005) and Wiberg type 3 patella (66.7% vs 9.1%; P < .001). There were statistically significant differences between the groups in the trochlear depth index (HPD vs RPD: 1.1 ± 1.7 vs 2.2 ± 1.5 mm; P = .039), sulcus angle (170.3° ± 13.7° vs 157.3° ± 16.0°; P = .007), Insall-Salvati index (1.1 ± 0.2 vs 1.3 ± 0.2; P = .034), and tibial external rotation angle (31.3° ± 7.8° vs 38.4° ± 8.5°; P = .009).

Conclusion

Patients in the HPD group presented with poorer trochlear and patellar development, lower patellar height, and less tibial external rotation compared with patients in the RPG group.

How does rectus femoris fibrosis affect gait?

We report on a female patient with stiff-knee gait resulting from rectus femoris fibrosis, following multiple injections into the quadriceps musculature. Treatment planning and outcome were aided by instrumented three-dimensional gait analysis. One year after surgery, improvements were found in walking speed, step length, anterior pelvic tilt, knee flexion in swing, and ankle dorsiflexion in swing. Instrumented three-dimensional gait analysis was a useful tool for characterizing gait impairments and detecting changes after surgical intervention. Intramuscular injections into the rectus femoris muscle should be avoided to prevent stiff-knee gait and associated disability.

Distal quadricepsplasty in children: 88 cases of retractile fibrosis following intramuscular injections treated in Benin

INTRODUCTION

Retractile fibrosis of the quadriceps (RFQ) is a physical and social handicap in children, and often results from a past history of quadriceps intramuscular injection. The aim of this study was to evaluate the therapeutic results of RFQ treated by distal quadricepsplasty using a modified Thompson-Payr procedure (DQPMTP).

HYPOTHESIS

Functional recovery will be good with DQPMTP.

PATIENTS AND METHODS

This is a descriptive retrospective 10-year study from 2002 to 2011, including 74 children (88 knees) less than 15 years old, admitted for RFQ and treated in Benin. The types of RFQ were: knee flexion loss of motion 16 cases (18.2%), lag of extension 54 cases (61.4%) and associated genu recurvatum, 18 cases (20.5%). Wasting of the thigh was found in all cases. An associated distal femoral osteotomy was performed to correct a bone deformity in 18 cases (20.5%).

RESULTS

There were 16 cases (18.2%) of poorly looking postoperative scars and 2 cases (2.3%) of fracture during physical therapy. Mean flexion ROM after surgery was 77.7°. Mean flexion increased from 77.7° to 108.5° following postoperative rehabilitation or a mean gain of 30.7°. The quadriceps muscle testing scores were at least 3/5. Results of DQPMTP were good in 80.7% of cases, as shown by mean active knee flexion of 108.5° with normal active extension. The results were satisfactory in 17 cases (19.3%).

DISCUSSION

DQPMTP has the advantage of cutting a minimum of blood vessels, thus limiting the risk of hematoma. Laterally placed incisions create less tension reducing the risk of skin necrosis. The clinical and radiological results of this series confirm those in the literature. Treatment of RFQ by DQPMTP provides satisfactory functional rehabilitation in patients, which confirms our hypothesis.

LEVEL OF EVIDENCE

Level IV, retrospective study without comparison.

Adult congenital permanent bilateral dislocation of the patella with full knee function: case report and literature review

Congenital permanent dislocation of the patella is a rare disorder of the knee joint in which the patella is permanently displaced, even in extension and is fixed on the lateral aspect of the femoral condyle. The dislocation is irreducible without surgical techniques. This rare condition is usually detected within the first decade of life, because of inability of active extension in the knee and impaired ability during walking. This report presents an unusual case of a 51-year-old man with bilateral congenital permanent dislocation of the patella. The pathology had never been treated because there were few symptoms. The patient presented with right knee pain caused by a fall on the knee during his work. The right knee was painful on the lateral side and the clinical signs were positive for pathology of the lateral meniscus, confirmed by MRI. The clinical and the imaging findings suggested a lesion of the lateral meniscus as the probable cause of the pain. Therefore we performed a knee arthroscopy, whose intra-operative findings confirmed the MRI findings. During the surgery we performed just a selective arthroscopic meniscectomy, without correcting patella dislocation, because the condition was unusually asymptomatic before the trauma.

First-time patellar dislocation with resultant habitual dislocation two years later, which was not demonstrated on plain X-rays halfway: a case report

We present an instructive case of habitual left patellar dislocation in which the patella had appeared odd due to lateral tilt relative to contralateral side, but had been radiologically confirmed to be on the trochlea at 1 year prior to the referral. An 11-year-old girl presented to our hospital 2 years after the left patella had dislocated with a 'giving way' when cutting to the left. Our physical and radiological examinations confirmed that the left patella was laterally tilted in the patellar groove with the knee in extension but was dislocated in flexion beyond 45°. In spite of these findings, she had been untreated at the previous hospital since all plain X-rays, including a skyline patellar view, had failed to demonstrate the dislocation. Consequently, in addition to reconstruction of medial patellofemoral ligament, she had to undergo a lateral retinacular release, which might have been unnecessary if treated earlier. This case illustrates that first-time patellar dislocation can gradually lead to habitual dislocation subsequently, and that cautious physical examinations in regard to patella tracking are essential since radiological examinations do not always reveal the pathophysiology of patellar instability.

Congenital dislocation of patella with ipsilateral hip flexion-abduction deformity: a case report

Iliotibial band tightness and its abnormal insertion on patella is one of the contributing factors in congenital dislocation of patella. Although hip flexion-abduction deformity is caused by a tight iliotibial band, as frequently seen in postpolio residual paralysis, an association of hip flexion-abduction deformity with congenital dislocation of patella has never been reported previously. Such a case was presented to us, and surgical repositioning of the patella was carried out by means of release of the tight iliotibial band from the patella besides other tight lateral structures along with medial augmentation and distal realignment of the quadriceps mechanism. The hip deformity was corrected spontaneously after release of the tight iliotibial band from the knee without need for additional surgery at the hip.

Vastus lateralis fibrosis in habitual patella dislocation: an MRI study in 28 patients

We studied 28 patients with habitual or recurrent dislocation of the patella with MRI of both thighs. Apart from the 2 patients whose dislocation could be related to trauma, we found signs of fibrosis of the vastus lateralis muscle in all the affected limbs of the 26 patients with an insidious onset of dislocation. This was seen as low signal intensity cords in the muscles in the T2 weighted image. Muscle degeneration was seen as high intensity signals in the T1 weighted image. In patients with unilateral disease, the vastus lateralis muscle of the affected side was hypotrophic, compared to that of the normal side. 2 patients underwent a biopsy of the affected muscle area. Histopathological examination revealed inflammatory cell infiltration, fibrosis, and muscle fiber degeneration. Fibrosis of the vastus lateralis muscle appears to be common in patients with habitual patella dislocation in our population, and may be the cause of the dislocation. Since release of such a contracture may be of value, MRI study of the thigh muscles is helpful in the evaluation of patients with this disorder.

New surgical technique for treatment of extraarticular knee ankylosis

Laboratory and clinical studies were conducted to evaluate a treatment regimen for extraarticular ankylosis of the knee. The study evaluated the use of a porcine biomembrane to prevent quadriceps adhesions. A canine model was studied to determine the cellular response to the membrane by evaluating biopsies at 3, 7, 14, and 21 days after surgery using light and scanning electron microscopy. The results showed that there was nonspecific inflammatory cell infiltration into the base (rough) layer of the biomembrane during the first few days, although fibroblasts were the dominant cellular response 7 days later. No significant tissue ingrowth was seen on the smooth (muscular interface) surface of the membrane. The clinical study applied the information gained from the canine model to a series of 23 patients who suffered from extraarticular knee ankylosis and who were treated with a surgical procedure in which the released interface between the femur and the muscle groups was protected with a piece of porcine biomembrane. Subjects were observed from 16 to 30 months (mean, 26 months) after surgery. An average increase in knee range of motion of 86 degrees was documented, and a 100% patient satisfaction rate was noted. The technique yields satisfactory results in terms of cost, range of motion, and postoperative pain.

Post-injection fibrosis of skeletal muscle: a clinical problem. A personal series of 169 cases

A personal series of 169 cases of post-injection fibrosis of skeletal muscle consisting of 78 cases of deltoid fibrosis, 84 cases of quadriceps fibrosis, 6 cases of gluteal fibrosis and one case of triceps fibrosis are presented. Discussion includes an extensive review of literature. A plea is made for pevention of the condition.