Figure - available from: Current Reviews in Musculoskeletal Medicine
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An AP and Lateral schematic demonstrating a transverse incision from superficial to deep through the patellar tendon that extends proximally, detaching the posterior 50% of the tendon from the patella (A). The superficial fibers are kept attached proximally and the deep fibers are kept attached distally. The tendon is lengthened and then reapproximated in an end to end fashion (B and E). The hamstring autograft (shown in orange) is sutured to the medial and lateral tendon edges and secured to the patella with suture anchors (denoted by black circles) (C and F)
Source publication
Purpose of Review
Patella baja is characterized by a loss of patellar height and can develop as either an acute or chronic complication following a knee injury or surgical procedure. The purpose of this review is to describe the diagnosis and management of patella baja and highlight the senior author’s surgical technique.
Recent Findings
The patho...
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Background:
Tibial plateau leveling osteotomy (TPLO) and cranial closing wedge ostectomy (CCWO) are common treatments for cranial cruciate ligament disease. These two techniques mainly differ in whether the proximal tibial fragment contains the attachment site of the patellar ligament. Currently, no reports compare how these techniques affect the...
Citations
... It is composed of a shortened patellar tendon, a decreased distance between the patellar lower pole and the proximal articular surface of the tibia, and a distal position of the patella in the femoral trochlea [6]. Patella baja can occur due to congenital causes or as a result of major knee surgical procedures, femoral nerve injury, or trauma around the knee [7]. The patella lies deeply within the quadriceps and patellar tendon and plays a role in increasing the mechanical advantage of the extensor mechanism [8]. ...
... In the case of patella baja, the patella is engaged in the trochlea throughout all ranges of motion rather than disengaging during terminal extension. This alteration could lead to anterior knee pain, impingement, or reduced range of motion [7,8]. ...
... It manifests in acute and chronic forms, with the acute type often arising postoperatively following knee injuries, surgeries, ligament reconstruction, trauma, arthroplasty, or osteotomy. Chronic patella baja results from quadriceps weakness, immobilization, or reflex sympathetic dystrophy [7,15,16,25,26]. Alterations in patellar height correlate with changes in biomechanical extension mechanisms, wherein normal patellar height disengages the patella from the trochlea during terminal extension, while patella baja maintains engagement throughout all ranges of motion, potentially leading to anterior knee pain, impingement, or restricted motion [7,8]. ...
Background and Objectives: Patella baja is a common complication after operative treatment for patellar fracture. This study aimed to investigate (1) the serial changes in patellar height and (2) the potential predictive factors for patellar height changes after tension band wiring (TBW) for patellar fractures. Materials and Methods: Forty-one patients who underwent TBW for patellar fracture between March 2019 and September 2022 were enrolled. To identify serial changes in patellar height, modified Blackburne–Peel index (mBPI) was assessed at just after surgery, at 3 months, at 6 months, at 1 year and at the final follow-up. Multiple regression analysis was conducted to identify factors correlated with mBPI difference between the contralateral side (considered as preoperative status) and injured side. Results: The postoperative mBPI exhibited a decline over time (mean mBPI immediately post operation/3 months/6 months/1 year/final follow-up: 0.69/0.63/0.63/0.62/0.61) Specifically, mBPI showed a significant reduction immediately post operation to 3 months (p < 0.001), although comparisons at other time points did not reveal significant differences. A lower position of the fracture was associated with a decrease in patellar height after surgery. Conclusions: Patellar height was mainly decreased from immediately post operation to 3 months. A fracture in a lower position of associated with decreased patellar height after the TBW of the transverse patellar fracture.
... For instance, Weale et al 27 reported that significant changes in the patellar tendon could be observed 8 months after TKA and tended to persist for up to 5 years after the procedure. 28 Therefore, the authors think that the clinical implications of significantly increased cellular hypoxia, oxidative stress, and apoptosis in the IPFP is relevant in the longer term. Additionally, injury and subsequent fibrosis in the IPFP have been reported to be associated with conditions such as persistent anterior knee pain, arthrofibrosis, patellar tendon disorders, and infrapatellar contracture syndrome, all of which can severely alter patient satisfaction after primary TKA. ...
Objective:
This study aimed to examine the cellular-level adverse effects of tourniquet use on the infrapatellar fat pad (IPFP) in patients undergoing primary total knee arthroplasty (TKA).
Methods:
Infrapatellar fat pad samples were collected in a prospective, randomized design to compare 2 groups of primary TKA patients with a tourniquet (T) and without a tourniquet (NT). The study included 80 knees of 58 patients with a mean age of 65.91 ± 9.04 years. The authors collected 3 samples from the T group (after exposure to the fat pad "t1," just before deflating the tourniquet "t2," just before fascia closure "t3") and 2 samples from the NT group (t1 and t3) for each patient. BAX, Bcl-2, and HIF-1α staining showed the extent of cellular hypoxia and apoptosis in IPFP cells, whereas the oxidative stress index (OSI) was determined using a biochemical method. The Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS), and Kujala score were used as clinical outcome measures.
Results:
The mean HIF-1α, BAX/Bcl-2, and OSI scores across all time points were significantly higher in the T group than in the NT group (p<0.001) (d=1.16, 2.9, and 0.9, respectively). The mean BAX/Bcl-2 (P=.030) and HIF-1α (P < .001) scores significantly peaked at t2 in the T group (d=-1.2 and -3.9, respectively). The OSI had higher levels at t1 (P=.011) and t3 (P=.073) (d=0.2 and 0.1, respectively) than at t2 in the T group. The third-month postoperative follow-up revealed that the mean KOOS, KSS, and Kujala score improved significantly compared to the baseline preoperative values (P < .001); however, there was no difference between the T and NT groups regarding the maximum and total knee range of motion or clinical outcome scores.
Conclusion:
Evidence from this study has shown that tourniquet use during primary TKA may be associated with significantly increased cellular hypoxia, oxidative stress, and apoptosis in the IPFP.
Level of evidence:
Level I, Therapeutic study.
Background
Use of a rapid rehabilitation protocol for postoperative recovery after recurrent patellar dislocation (RPD) has gradually gained attention; nonetheless, evidence of its safety and effectiveness is lacking.
Purpose
To compare the short-term postoperative outcomes of early rapid rehabilitation with those of conservative rehabilitation in patients with RPD.
Study Design
Randomized controlled trial; Level of evidence, 2.
Methods
A total of 50 patients with RPD who underwent tibial tubercle osteotomy combined with medial patellofemoral ligament reconstruction were enrolled between January 2018 and February 2019. Postoperatively, the patients were randomly assigned to either the early rapid group (rapid group; n = 25 patients) or the conservative group (control group; n = 25 patients) for rehabilitation training. The rapid group underwent faster progression in weightbearing and range of motion (ROM) training. Knee joint functional scores, ROM, bilateral thigh circumference differences, and imaging data were recorded preoperatively and at 6 weeks and 3, 6, 12, and 24 months postoperatively for comparison. Postoperative complications were recorded over the 24-month follow-up period.
Results
The baseline data did not significantly differ between the 2 groups. Postoperatively, compared with the control group, the rapid group had higher Tegner scores at 6 weeks and 3 months; higher Lysholm scores at 3 and 6 months; higher International Knee Documentation Committee scores at 6 weeks, 3 months, and 12 months; better ROM; and smaller bilateral thigh circumference differences at 24 months ( P < .05 for all). However, no differences were observed in the Tegner, Lysholm, and International Knee Documentation Committee scores at 24 months postoperatively. At the 6-week and subsequent follow-up visits, the Caton and Insall indices were lower in the control group than in the rapid group ( P < .01 for all). Moreover, compared with the control group, the rapid group had a lower incidence of patella baja at 24 months (0% vs 17%) and fewer complications during the whole follow-up period ( P < .01).
Conclusion
Early rapid postoperative rehabilitation appears to be safe and effective for patients who undergo tibial tubercle osteotomy combined with medial patellofemoral ligament reconstruction to treat RPD. In the short term, this approach was shown to be more advantageous than conservative rehabilitation in improving functional scores, allowing an earlier return to daily activities, although the lack of difference at 24 months implies no long-term benefits. In addition, it potentially helped to prevent the occurrence of complications, including patella baja.
Registration
ChiCTR1800014648 (ClinicalTrials.gov identifier).
Patella alta (PA) and patella baja (PB) affect 1–2% of the world population, but are often underreported, leading to potential complications like osteoarthritis. The Insall-Salvati ratio (ISR) is commonly used to diagnose patellar height abnormalities. Artificial intelligence (AI) keypoint models show promising accuracy in measuring and detecting these abnormalities.
An AI keypoint model is developed and validated to study the Insall-Salvati ratio on a random population sample of lateral knee radiographs. A keypoint model was trained and internally validated with 689 lateral knee radiographs from five sites in a multi-hospital urban healthcare system after IRB approval. A total of 116 lateral knee radiographs from a sixth site were used for external validation. Distance error (mm), Pearson correlation, and Bland–Altman plots were used to evaluate model performance. On a random sample of 2647 different lateral knee radiographs, mean and standard deviation were used to calculate the normal distribution of ISR. A keypoint detection model had mean distance error of 2.57 ± 2.44 mm on internal validation data and 2.73 ± 2.86 mm on external validation data. Pearson correlation between labeled and predicted Insall-Salvati ratios was 0.82 [95% CI 0.76–0.86] on internal validation and 0.75 [0.66–0.82] on external validation. For the population sample of 2647 patients, there was mean ISR of 1.11 ± 0.21. Patellar height abnormalities were underreported in radiology reports from the population sample. AI keypoint models consistently measure ISR on knee radiographs. Future models can enable radiologists to study musculoskeletal measurements on larger population samples and enhance our understanding of normal and abnormal ranges.
