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.

UNASSIGNED: The phenomenon of a floating patella or ipsilateral bifocal rupture of the extensor apparatus is an extremely rare injury, with few cases reported in the literature. The aim of this case study is to report an unprecedented event: the simultaneous trans-tendinous rupture of both quadriceps and patellar tendons in a young adult without predisposing factors, emphasizing the need for awareness in diagnosis and management, and suggesting a new avenue for research in prevention and rehabilitation.
METHODS: We report the case of a 35-year-old patient with no significant medical history, who experienced this injury following a sudden start in a sprint without prior warm-up. The clinical examination revealed a swollen, painful knee with active extension deficit, patellar ascent, and a sub patellar hiatus. Magnetic Resonance Imaging (MRI) confirmed a trans-tendinous rupture of both the patellar and quadriceps tendons.
UNASSIGNED: Tendon repair was performed using end-to-end sutures and a figure-8 reinforcement with the semitendinosus tendon, along with gracilis plastie to strengthen the patellar tendon repair. This methodological approach is discussed in the context of its effectiveness and potential implications for future surgical management of similar injuries.
CONCLUSIONS: After a 12-month follow-up, the patient exhibited highly satisfactory results, resuming both professional and sporting activities. To our knowledge, this is the first published case of a trans-tendinous rupture of the extensor apparatus tendons. This observation serves as a reference in understanding the mechanism and surgical management of such lesions, emphasizing the need for further research and clinical vigilance in similar cases.

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.

Patellar tendon rupture is a rare but serious complication resulting in loss of knee extension that may develop during and after total knee arthroplasty and negatively affects the patient\'s quality of life. There are a number of surgical options available, from primary repair to reconstruction. Peroneus longus tendon autograft has begun to be used for knee extensor mechanism repair in recent years. In this case report, we aimed to present the case of a patient with traumatic patellar tendon rupture after revision knee arthroplasty. In conclusion, patellar tendon reconstruction using peroneus longus tendon autograft can be considered a successful method in selected patients following knee arthroplasty. It allows early rehabilitation via stable graft fixation and provides good clinical and functional outcomes in the late period.

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.

Alkaptonuria (AKU) is a rare hereditary disorder of tyrosine degradation. The disorder is characterized by the accumulation of a pigment called homogentisic acid. Its accumulation can lead to the breakdown of connective tissue, including tendons. This report presents a 46-year-old male with a history of bilateral total knee arthroplasty (TKA) who sustained bilateral patellar tendon rupture after an acute injury. A single-stage bilateral knee revision with direct repair of the extensor mechanism augmented with Achilles allograft was performed. The procedure was successful, and the patient had an excellent post-operative outcome at one year post-operatively. This case attempts to highlight the possible complications from AKU in order to better counsel patients with this condition who are undergoing TKA.

UNASSIGNED: Rupture to the patellar tendon caused by athletic activities is rare, but if not treated promptly, it can lead to unfavorable results such as quadriceps contracture, residual weakness, and reduced knee flexibility.
METHODS: A female patient who injured her knee seven months ago while twisting it experienced pain, instability, and tested positive for the anterior drawer and Lachman tests. Radiology results showed a complete tear of the anterior cruciate ligament (ACL) and a partial tear of the patellar tendon on the MRI scan of the right knee. We used a direct end-to-end approximation technique for the patellar tendon, with augmentation through the transosseous site at the patella proximally and tibial tubercle distally, without using a graft. The outcome was good, and this is the first reported case of a successful patellar tendon reconstruction without using implants, synthetic augmentation, or graft.
UNASSIGNED: This technique could be a promising alternative to repair a chronic patellar tendon rupture without using expensive methods. The use of fiber tape augmentation can be a practical solution for treating a neglected patellar tendon rupture in conjunction with aligamentous injury that requires graft repair.
CONCLUSIONS: The use of fiber tape augmentation might be an alternative method for treating a neglected patellar tendon rupture with concurrent ligament injury needing graft repair. We believe that this technique is easily reproducible and warrants further investigation.

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.