Risk Of Patellar Fracture Research Articles

Small (3.2-mm), Short, Oblique Patellar Tunnels for Patellar Fixation in MPFL Reconstruction

Multiple techniques exist for patellar graft fixation during medial patellofemoral ligament (MPFL) reconstruction, each with their respective advantages and disadvantages. In recent studies, the use of 2 small (3.2-mm), short, oblique patellar tunnels with looped graft has been shown to be effective for patellar fixation during MPFL reconstruction. This technique does not appear to be associated with the same risk of patellar fracture as the use of larger (4.5-mm) transpatellar tunnels. A recent retrospective study also reported decreased risk of recurrent patellar instability and decreased cost compared with the use of suture anchors for patellar fixation, which is currently the most common modality. Given these promising findings relative to existing techniques for patellar fixation, further description of the senior author’s technique for using these small (3.2-mm), short, oblique patellar tunnels is provided. This technique is safe, efficacious, and cost-conscious and should be considered a viable option for patellar fixation during MPFL reconstruction.

Combined Soft Tissue Reconstruction of the Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament

Patellar dislocation is a major orthopaedic concern in pediatric and adult populations, with both conservative and surgical options available. Several surgical techniques of the combined or isolated reconstruction of the medial patellofemoral ligament are described in the literature using different grafts, locations, and types of fixations, providing different advantages and disadvantages. New recent developments in cadaveric dissection studies have unveiled the importance of structures that were neglected until recently, such as the medial quadriceps tendon–femoral ligament, which provides a connection between the medial femur and the quadriceps tendon component of the knee extensor mechanism. Hence, we present a surgical technique with combined reconstruction of the medial patellofemoral ligament and medial quadriceps tendon–femoral ligament without the use of hardware and with no need for patellar or femoral drilling (no physis compromise or risk of patellar fracture), which can be used concomitantly with other bony procedures.

Comparison of suture anchor vs. interference screw technique for patellar fixation for medial patellofemoral ligament reconstruction

Summary Background There are numerous techniques for MPFL reconstruction, however, one single technique has not been proven to be superior to another. Suture anchor reconstruction has been shown to provide stable fixation while decreasing the risk of patellar fracture. Purpose The aim of the study was to compare the stiffness and clinical load to failure of two common MPFL reconstruction techniques. Our hypothesis was that there would be no significant difference in the stiffness and the clinical load to failure between the suture anchor and interference screw reconstructions. Methods Eight pairs of fresh frozen cadaveric knees were randomized into two groups undergoing MPFL reconstruction using either a suture anchor technique (n = 8) or an interference screw technique (n = 8). Testing was performed at 0, 30, 60, and 90 degrees of flexion for the native knee, transected medial structures, and reconstructed MPFL. Next, the reconstructed MPFL specimens were tested until failure in 0 degrees of flexion. t-Test, One-Way ANOVA, and repeated measures of ANOVA were used for statistical analysis, p values less than 0.05 were considered significant. Results The average stiffness for the suture anchor and interference screw reconstructions was 12.02 ± 3.96 N/mm and 14.21 ± 4.20 N/mm, respectively (t-test, p = 0.27), while average clinical load to failure was 256.57 ± 54.1 N and 237.81 ± 23.82 N, respectively (t-test, p = 0.38). There was no significant difference in stiffness between the suture anchor and interference screw techniques at 0, 30, and 60 degrees of flexion. Conclusions The suture anchor and interference screw reconstruction techniques produce comparable stiffness for sub-failure testing at 0 and 30 degrees of flexion. For testing to failure, the initial stiffness for both reconstruction techniques have been shown to be concordant with previously published values for the native MPFL. Both reconstruction techniques provide greater ultimate failure loads than those reported for the native MPFL in previous studies. Suture anchor reconstruction described in our study provides another reliable option for the reconstruction of the medial patellofemoral ligament. Clinical relevance Our study provides biomechanical data that the suture anchor technique described in this study provides comparable fixation compared to interference screw fixation and has the potential of reducing fracture to patella particularly in the pediatric population with small patellae.

Increased Patellar Fracture Rate in Total Knee Arthroplasty With Preoperative Varus Greater Than 15°: A Case-Control Study

BackgroundManagement of severe varus deformity requires soft tissue balancing for implantation of low-constraint knee prosthesis. Patellar complications have been rarely studied in this specific group. Our hypothesis was that severe genu varum (>15°) would increase the rate of patellar complications. MethodsUsing a prospective cohort of 4216 prostheses performed at a single center beginning in 1987, we analyzed 280 prostheses having preoperative varus greater than 15°, compared to 673 total knee arthroplasties (TKAs) with a preoperative hip-knee-ankle angle of 180° ± 2°. Preoperative and postoperative clinical and radiological characteristics were compared between the 2 groups, with particular attention paid to patellar complications. ResultsAverage follow-up was 40.2 months (24-239). The mean preoperative Knee Society Score (KSS) was statistically higher in the normal (hip-knee-ankle angle 180° ± 2) axis group (62.65 vs 37.47, P = .001). At the last follow-up, no significant difference was found between the 2 groups in terms of postoperative KSS (87.5 in the varus group vs 87.3 in the normal axis group, P = .87). The rate of satisfied patients was identical between the 2 groups (85.3% vs 88.8%, P = .49). However, at mid-term, there were more patellar fractures in the varus group (2.9% vs 0.9%, P = .005). A significantly lower patellar height in both the varus group and the group of patella fractures (P < .001) was also found. ConclusionTKA in severe varus knees produces a KSS equivalent to TKA in knees with a mechanical axis of 0 ± 2. The risk of patellar fracture could initiate a decline in patella resurfacing in patients with major varus deformation, especially in case of a preoperative patella baja.

Anterior Cruciate Ligament Reconstruction Basics: Bone–Patellar Tendon–Bone Autograft Harvest

Anterior cruciate ligament reconstruction with bone–patellar tendon–bone autograft has long been considered the graft preference for young, active patients with anterior cruciate ligament injuries. The central-third of the native patellar tendon is a reliable graft and is the preferred option for competitive athletes given its excellent track record with high return-to-play rates and low failure rates. Disadvantages to using this graft include donor site morbidity and associated postoperative anterior knee pain, the risk of patellar fracture or patellar tendon tear, and the potential for graft-construct mismatch. In this Technical Note, we describe our preferred technique for bone–patellar tendon–bone autograft harvest and preparation for anterior cruciate ligament reconstruction.

Patellar Fractures Following Total Knee Arthroplasty: A Review

There are several periprosthetic complications associated with total knee arthroplasty, with femoral fracture as the most common and patellar fractures as the second most common. Patellar fractures are challenging complications that occur almost exclusively on the resurfaced patellae, although unresurfaced patellar fractures have been reported in literature. The purpose of this study is to describe the anatomy of the patella, the etiology of patellar fractures, and strategies to treat and manage these fractures following knee arthroplasty. The vascular supply to the patella may be compromised during total knee arthroplasty and special care must be taken to preserve it. Vessel injury may result in further complications, most notably avascular necrosis with subsequent fracture. Other patient-, surgical-, and prosthetic-related factors can contribute to increased risk of patellar fracture. Patellar fractures are classified into three types. Type I fractures have an intact extensor mechanism with a stable implant. Type II fractures have a complete disruption of the extensor mechanism with or without a stable implant. Type III fractures, which are further subclassified into types IIIa and IIIb, have an intact extensor mechanism but a loose patellar component. While type IIIa fractures have reasonable remaining bone stock, type IIIb fractures have poor bone stock. Type I patellar fractures may be best managed nonoperatively, but types II and III patellar fractures often necessitate surgical intervention. Patellectomy should be reserved for comminuted fractures, as well as fractures in patients with poor bone stock. Larger prospective randomized studies are necessary to better evaluate the treatment algorithm for patellar fractures following total knee arthroplasty.

Aperture fixation instead of transverse tunnels at the patella for medial patellofemoral ligament reconstruction

Medial patellofemoral ligament (MPFL) reconstruction is an effective option for the treatment of recurrent patellar instability. Most techniques utilize the passage of a tendon graft through tunnels at the patella with the risk of patellar fracture. The purpose of this study was to investigate the strength of the recent MPFL reconstruction techniques (transverse tunnel, interference screw, anchor, and docking technique). Thirty-six saw bones were divided into four groups (transverse tunnel, interference screw, anchor fixation, and docking technique) with nine patellae in each. Patella-tendon constructs were pre-loaded to 10N and cyclically loaded for 20 cycles from 2 to 30N under load control at a rate of 5N/sec. The construct was then tested to failure at a constant displacement rate of 6mm/sec. Ultimate load (N), stiffness (N/mm), and failure mode were recorded for each specimen. The docking group had lower ultimate load [106 (SD 41) N] and stiffness [14 (SD 2) N/mm] values than the other groups tested (P=0.007). The anchor group had lower stiffness [21 (SD 6) N/mm] values than the tunnel group [28 (SD 3) N/mm (P=0.01)] and the interference screw group [31 (SD 6) N/mm, (P=0.004)]. There was no significant difference in the ultimate load between anchor [299 (SD 116) N], tunnel [304 (SD 140) N], and interference screw groups [241 (SD 103) N] (n.s.). Aperture fixation techniques, especially interference screw fixation, were as strong as the technique utilizing tunnels in the patella for MPFL reconstruction.

Strengthening of the patellofemoral ligament by rivet fixation of the dissociative semitendinosus tendon for recurrent patellar dislocation

Objective To investigate therapeutic effects of rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament for management of recurrent patellar dislocations.Methods From March 1999 to January 2008, 57 cases of recurrent patellar dislocation were treated in our department. They were 19 males and 38 females, with an average age of 24. 3 (range, 17 to 29) years.Their disease courses ranged from 1 to 4 years (average, 2.6 years) . Of them, 15 (group A) were treated with repair of the medial retinaculum and patellofemoral ligament, 19 (group B) with reconstruction of the medial patellofemoral ligament, and 23 (group C) with rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament. All the patients were followed up in the out-patient department 12months later. Functional recovery was evaluated by the Lysholm scores and the Insall evaluation. Results There were statistical significant differences between the preoperative and postoperative Lysholm scores in the 3 groups respectively. Group C had a comparable therapeutic effect with group B( P > 0. 05) . The postoperative Lysholm score for group C was significantly higher than that for group A ( P 0. 05 ) . Conclusion For recurrent patella dislocations, rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament can be as effective as the traditional medial patellofemoral reconstruction, but it is simpler and less invasive and may reduce the risk of patellar fracture. Key words: Patellar dislocation; Patellofemoral ligament; Reconstructive surgical procedures