OBJECTIVE: This systematic review aims to delineate the various methods to repair or reconstruct the patellar tendon using the available literature.
METHODS: MEDLINE and PubMed electronic databases were searched for English language clinical studies involving patellar tendon rupture repair or reconstruction that reported patient-reported outcome scores (PROS) between January 1st, 1953 and June 17th, 2021. Data was extracted on full text articles to collect functional outcome scores and rupture category, including acute, chronic, post-total knee arthroplasty (TKA) and post-anterior cruciate ligament reconstruction (ACLR).
RESULTS: Twenty-three studies with a total of 738 patients were included. Of the 14 studies including acute repairs, mean postoperative Lvsholm scores ranged from 84 to 99.5. Knee Society Score (KSS) and knee range of motion (ROM) measurement were the most widely reported outcomes in the chronic setting. The average postoperative KSS scores ranged from 70 to 87.7. Of the six studies that included patellar tendon repairs/reconstructions in the setting of prior TKA, the most frequently reported outcomes were KSS scores and knee ROM measurements. The average postoperative KSS scores for the three cohorts reporting reconstruction with allograft ranged from 79 to 88 as compared to the average postoperative KSS score for reconstruction with autograft of 70.
CONCLUSIONS: Despite this heterogeneity, we concluded: (1) in the primary setting, cerclage augmentation yields the lowest lysholm scores and should not be considered, although primary repairs with and without augmentation yield comparable postoperative lysholm scores, (2) in the chronic setting, repair with augmentation and reconstruction yielded similar results aside from in post-TKA patients where allograft reconstruction yielded superior KSS scores.

We present a case of a neglected patellar tendon rupture, misdiagnosed as an anterior cruciate ligament tear, in a 12-year-old child with open physis without an avulsion fracture. The patient was treated with an ipsilateral hamstring tendon autograft with preserved distal insertions, a transpatellar tunnel, and a transtibial fixation. At the final follow-up, the patient had a full range of motion and a fully functional knee. The described technique results in complete muscle strength, full range of motion, and pain-free gait. It can be used in chronic patellar tendon ruptures and is a valuable addition to the therapeutic quiver for this type of injury.

OBJECTIVE: This case report describes in detail a rehabilitation and exercise program following surgical treatment of patellar tendon rupture and offers postoperative therapeutic goals and recommendations, with the aim of expediting the resumption of activities of daily living and sports participation following the surgical procedure. In addition, this report analyzes the cause of the patellar tendon rupture in this case.
METHODS: Case report.
METHODS: The patient, a 25-year-old male recreational athlete (height: 184 cm; weight: 80 kg; right-hand dominant), experienced a complete rupture of the patellar tendon upon landing on the left lower extremity during an unopposed dribble turn.
UNASSIGNED: A well-structured rehabilitation program was implemented. Passive knee flexion range of motion (ROM) exceeded 90° at week 5 and was fully recovered at week 16. A second surgery was performed at week 19 to remove the decompression wires, and the patient progressively resumed basic physical and specialized training at 7 months post-surgery.
METHODS: Morphometric and functional tests were performed to measure the effectiveness of rehabilitation throughout the postoperative process.
CONCLUSIONS: Early surgical repair and an immediate postoperative rehabilitation program have a positive impact on knee ROM, function, and muscle strength. The causes of the patellar tendon rupture in this patient included long-standing uncontrolled patellar tendinopathy, impaired mobility of the ankle and hip joints, poor landing technique, and muscle strength imbalances.

UNASSIGNED: To review reliable techniques for reconstructing or repairing chronic patella tendon tears and describe the unique case report of chronic patellar tendon tear with heterotopic ossification (HO).
UNASSIGNED: A 47-year-old male presented with chronic patellar tendon tears with HO, resulting in an inability to extend the right knee fully. Krackow suture repair augmented by autograft semitendinosus and gracilis was employed after debriding intra-substance patella tendon HO and fibrotic tissue. The repair was augmented using a method described by Chen et al. Postoperative recovery was uneventful, and the patient demonstrated an excellent Knee Society Score (86/100) at 6 months of follow-up. Proximal migration of the patella, poor tissue quality, scar tissue formation, and quadriceps atrophy pose unique challenges in managing chronic patellar tendon tears.
UNASSIGNED: HO increased the probability of patella baja after the reconstruction. To alleviate that, precise pre-op planning, careful method selection, and proper execution of the selected method are very important. A comprehensive review of 14 different methodologies for managing chronic patellar tendon tears, comprising eight case series and six case reports, was conducted. The selection of an appropriate technique should be based on individual patient characteristics, resource availability, and the surgeon\'s expertise.

The purpose of this systematic review is to report outcomes and complications following the reconstruction of chronic patellar tendon ruptures. Four databases (Cochrane Database of Systematic Reviews, PubMed, Embase, MEDLINE) were searched from inception to July 2021. Inclusion criteria included articles that (1) analyzed outcomes and complications following chronic patellar tendon reconstruction (>4 weeks from injury to repair), (2) were written in English, (3) greater than five patients, and (4) a minimum 2-year follow-up. Exclusion criteria included (1) non-original research and (2) patellar tendon repair/reconstruction with prior total knee arthroplasty. Data on outcome metrics and complications were extracted from the included studies and reported in a qualitative manner. Nine studies (number of patients = 96) were included after screening. Seven studies analyzed autograft reconstruction, and three of those seven studies analyzed reconstructions with additional augmentation. The remaining two studies evaluated reconstruction utilizing a bone-tendon-bone (BTB) allograft. Four of the autograft studies (n=40 patients) showed a range of post-operative mean Lysholm scores of 74-94. Additionally, four studies reported a post-operative extensor lag of 0-3°. Post-operative protocol for autograft studies included delayed motion and was either contained to a bivalved cast or a hinged knee brace for six weeks. The two allograft studies reported a range of mean Lysholm scores from 62 to 67, and each immobilized the leg in full extension until six weeks. While chronic patellar tendon ruptures are a rare injury of the extensor mechanism, there are viable options for reconstruction. Overall, chronic patellar tendon ruptures reconstructed with both autograft and allograft will provide fair to good outcomes with low complication rates. Following surgery, immobilization for at least six weeks should be emphasized to protect the graft and optimize patient outcomes.

The extensor mechanism of the knee can be damaged due to various modes of injury, which, in most cases, will require urgent surgical intervention for repair. Single patellar tendon ruptures are uncommon, but simultaneous bilateral events are even rarer and have been scarcely reviewed in English literature. Research in this area is mainly confined to case series, with some literature reviews but no evidence of more substantial analysis. Therefore, this systematic review was done to analyse the existing literature on bilateral simultaneous patellar tendon ruptures and propose a systematic and standardised approach to diagnosing and managing these injuries. A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search terms included \'bilateral patellar tendon rupture\', \'bilateral\', \'patellar\', \'tendon\' and \'rupture\'. Three independent reviewers conducted searches in PubMed, OvidSP for Medline, Embase and the Cochrane Library using the same search strategy. The eligibility criteria included studies on bilateral concomitant patellar tendon rupture published in English. Bilateral simultaneous patellar tendon ruptures of traumatic and atraumatic origin in human patients were included. The study types comprised case reports and literature reviews. The key limitation of this study was the low number of patients covered by the eligible literature. Patellar tendon ruptures are a rare and scarcely documented injury, and there is a need for studies with a high level of evidence, especially regarding surgical treatment choice and methods, as well as post-operative management, which could potentially lead to improved outcomes in the management of this injury.

OBJECTIVE: Extensor mechanism lesion after total knee arthroplasty (TKA) is a catastrophic complication. Reconstruction with extensor mechanism allograft (EMA) has been described as a sound salvage procedure. Its effectiveness at long term and in septic cases is still under scrutiny. The long-term results of EMA reconstruction for chronic extensor mechanism failures following aseptic and septic revision TKA have been analysed.
METHODS: From the institutional database, 35 patients with a revision TKA (RevTKA) undergoing EMA reconstruction from 2005 to 2015 have been retrospectively identified. A history of periprosthetic joint infection (PJI) was found in 13 (37%) patients. The mean follow-up was 81.2 months (± 34.7, range 3-120). EMA failures were considered for lag more than 20°, Knee Society Score (KSS) less than 60 points, and/or in the case of revision of the allograft.
RESULTS: The mean KSS improved from 35.9 (± 16.9, range 0-54) to 86.6 (± 10.4, range 54-99) points in the aseptic group (p < 0.001) and from 27.5 (± 11.6, range 10-44) to 79.4 (± 16.3, range 48-94) points in the septic group (p < 0.001). The extensor lag changed from 48.4° (± 14.5, range 30-90) to 4.6° (± 10.8, range 0-50) in the aseptic group (p < 0.001) and from 56.5° (± 20.8, range 30-90) to 6.1° (± 6.8, range 0-20) in the septic group (p < 0.001). The mean postoperative flexion was 105.2° (± 13.2, range 75-130) in the aseptic group and 102.7° (± 12.5, range 80-120) in the septic group (p = 0.32). Three failures (14% of the cases) occurred in the aseptic group and five in the septic group (38% of the cases). The overall survivorship at 10 years was 83.3% (22 cases, CI95 94.2-121.7) vs 58% (13 cases, CI95 67.2-111.7) in the aseptic and septic group, respectively (p = 0.01).
CONCLUSIONS: EMA reconstruction after extensor mechanism disruptions in TKA is a reliable salvage procedure. The septic nature of the revision decreased the functionality of the knee joint after EMA, but it did not represent a risk factor for re-ruptures or recurrence of infection.
METHODS: Level III.

UNASSIGNED: Patellar tendon is one of the most important components of the knee extensor mechanism, which consisted of quadriceps femoris muscle, quadriceps tendon, patellar bone and patellar tendon. The total disruption of patellar tendon will lead to disability and significant morbidity of the patient, or even worse, the patient is disabled to walk. The incidence of patellar tendon rupture is uncommon and most commonly found in the third to fourth decade of life. We present a case of total patellar tendon rupture in a teenager with primary repair with suture anchor.
METHODS: We presented a case of 14-year-old male with acute patellar tendon rupture accompanied by tibial tubercle avulsion after injury during basketball game. We treated by four-strands Krakow\'s suture that stitched to three sutures anchor, while cancellous screw plus washer introduced as internal fixation of bony avulsion at tibial tubercle.
UNASSIGNED: Range of motion and International Knee Documentation Committee (IKDC) score had been followed up within 2 years with good result. Full range of motion and the IKDC score 89.7 were achieved without major complication such as pain and infection. The patient was able to return into sport activities.
CONCLUSIONS: The combination of cancellous screw with washer and three suture anchors lead to a good result in acute total rupture of patellar tendon with bony avulsion at tibial tubercle.

Native patellar tendon injuries are seen in younger patients compared to quadriceps tendon ruptures. Up to a third of the patients may have local (antecedent tendinopathy and cortisone injections) or systemic risk factors (obesity, diabetes, hyperparathyroidism, chronic renal failure, fluoroquinolone or statin use) of injury, these are more frequent in bilateral disruptions. Complete extensor mechanism disruptions should be repaired surgically. Although isolated primary repair has been reported to have good outcomes in younger patients with acute tears and good tendon quality, augmentation of the repair with autograft, allograft or synthetic material should be considered in patients with poor tendon quality, chronic tears or tendon defects. High rates of return to work/sports have been reported in native patellar and quadriceps tendon tears, with re-rupture rates <5%. Extensor mechanism disruptions in patients with a total knee arthroplasty are challenging due to older age, systemic co-morbidities and poor local conditions, resulting in inferior outcomes compared to native extensor mechanism injuries. Some form of augmentation with autograft, allograft or synthetics is advisable in all cases. Salvage procedures such as whole extensor mechanism allografts provide acceptable outcomes in multiply operated knees with extensive bone and soft tissue deficits.

The management of extensor mechanism lesions after total knee replacement is still associated with an unacceptably high complication rate, especially in its chronic setting. In this study, we report on 4 patients with chronic (> 3 months) patellar tendon rupture after knee arthroplasty, who were treated with a novel procedure of staged patella advancement prior to reconstruction with autografts. Initially, a unilateral frame was applied connecting the patella with the tibial shaft. The construct allowed for gradual distal advancement of the patella based on the Ilizarov principles. After achieving the desired patella height, the frame was removed, and the patellar tendon was reconstructed with hamstrings. All four patients experienced a significant improvement in extensor lag by a mean of 38.0°, while Knee society scores increased by a mean of 38.5 units. No substantial loss in active knee flexion was observed. Our findings suggest that our technique yields favorable outcomes in patients with patellar tendon disruption in the setting of a total knee arthroplasty.