Introduction. Mechanical integrity of patella can be weakened by the technique of removing the articulating surface. The senior author developed the technique of maintaining subchondral bone of the lateral patellar facet in early 1980s. Though laboratory studies have demonstrated deleterious effect of excessive resection of patella on the strains in the remaining bone under load; clinical studies have not shown the importance of strong subchondral bone of lateral facet to have an effect on patellar fracture prevalence. We present the results of our patellar resection technique preserving the subchondral bone of lateral facet. Methods. 393 TKRs were performed between 1989 and 1996 using cruciate substituting modular knee with recessed femoral trochlear groove and congruent patello-femoral articulation. 45 patients with 48 knees died and 37 patients with 41 knees were lost to follow-up. Three hundred and four knees were followed for an average 10 years (range 5 -16 years). Patellar surface was resected with an oscillating saw without the use of cutting guide. The medial facet and most of the articular cartilage of the lateral facet was resected, while preserving the subchondral bone of lateral facet. An all-polyethylene implant with single peg was used in most cases. Results. There have been two fractures in the cohort with prevalence of 0.66%. Eight TKRs were revised for synovitis and osteolysis. Patellar osteolysis was found in 4 of these cases, with loosening of 3 of these patellae, and 1 patellar fracture. Two patellar implants had global radiolucencies and were considered loose. The average knee score in unrevised knees improved from 48.6 to 92.2, while functional scores improved from 50 to 81.1. Conclusion. We believe that maintaining this anatomic landmark allows for preserved patellar strength, and in association with a femoral component with a recessed trochlear groove, has resulted in our low patellar fracture rate in primary TKR and revision cases for patellar osteolysis

Patellar fractures account for approximately 1% of all fractures. Open reduction and internal fixation is recommended to restore extensor continuity and articular congruity. However, complications such as nonunion and symptomatic hardware, still exist. Furthermore, there is a risk of re-fracturing of the healed bone during the removal of the implants. Magnesium (Mg), a biodegradable metal, has elastic moduli and compressive yield strength that are comparable to those of natural bone. Our previous study showed that released Mg ions enhanced fracture healing. However, Mg-based implants degrade rapidly after implantation and lead to insufficient mechanical strength to support the fracture. Microarc oxidation (MAO) is a metal surface coating that reduces corrosion. We hypothesized that Mg pins, with or without MAO, would enhance fracture healing radiologically, mechanically, and histologically, while MAO would decrease degradation of Mg pins. Patellar fracture was performed on forty-eight 18-week-old female New Zealand White rabbits according to established protocol. Briefly, the patella is osteotomized transversely and a tunnel (1.1mm) was drilled longitudinally through the two bone fragments. A pin (1 mm, stainless steel, Mg, or MAO-Mg) was inserted into the tunnel. The reduced construct was stabilized with a figure-of-eight band wire (⊘ 0.6 mm stainless steel wire). Cast immobilization was applied for 6 weeks. The rabbits were euthanized at week 8 and 12 post-operation. Microarchitecture and mechanical properties of the repaired patella were analyzed with microCT and tensile testing respectively. Histological sections of the repaired patella were stained. To evaluate the effect of the MAO treatment on degradation rate of Mg pin, the volume of the Mg pins in the patella was measured with microCT. At week 8, both Mg and Mg-MAO showed higher ratio of bone volume to tissue volume (BV/TV) than the control while there was no significant different between Mg and Mg-MAO. At week 12, Control, Mg, and Mg-MAO groups showed enlarged patella when compared to the normal patella. Tissue volume (TV) and bone volume (BV) of the patella in Mg and Mg-MAO were larger than those in the Control group. However, the Control had higher ratio of bone volume to tissue volume (BV/TV), TV density, and BV density than Mg and Mg-MAO. Tensile testing showed that the mechanical properties of the repaired patella (failure load, stiffness, ultimate strength, and energy-to-failure) of Mg and Mg-MAO were higher than that of the control at both week 8 and week 12. Histological analysis showed that there was significant new bone formation in the Mg and Mg-MAO group compared with the Control group at week 8 and 12. The degradation rate of the MAO-coated Mg pins was significantly slower than those without MAO at week 8 but no significant difference was detected at week 12. Mechanical, microarchitectural, and histological assessments showed that Mg pins, with or without MAO, enhanced fracture healing of the repaired patella compared to the Control. MAO treatment enhanced the corrosion resistance of the Mg pins at the early time point

For the management of displaced patellar fractures, surgical fixation using cannulated screws along with anterior tension band wiring is getting popular. Clinical and biomechanical studies have reported that using cannulated screws and a wire instead of the modified tension band with Kirschner wires improves the stability of fractured patellae. However, the biomechanical effect of screw proximity on the fixed construction remains unclear. The aim of this study was to evaluate the mechanical behaviors of the fractured patella fixed with two cannulated screws and tension band at different depths of the patella using finite element method. A patella model with simple transverse fracture [AO 34-C1] was developed; the surgical fixation consisted of two 4.0-mm parallel partial-threaded cannulated screws with a figure-of-eight anterior tension band wiring using a 1.25-mm stainless steel cable. Two different locations, including the screws 5-mm and 10-mm away from the leading edge of the patella, were used. A tension force of 850 N was applied on the patellar apexes at two loading angles (45° and 0° [parallel] to the long axis) to simulate different loading conditions while knee ambulation. The proximal side (base) of the patella was fixed, and the inferior articular surface was defined as a compression-only support in ANSYS to simulate the support from distal femur condyles. Compression-only support enables the articular surfaces of the present patella to only bear compression and no tension forces. Under different loading conditions, the fixed fractured patella yielded higher stability during 0° loading of tension force than during 45° loading. When the screws were parallel placed at the depth of 5 mm away from the patellar surface, the deformation of patellar fragment and maximum gap opening at the fracture site were smaller than those obtained by screws placed at the depth of 10 mm away from the patellar surface. Compared to the superficial screw placement, the deeper placement (10 mm) increased the maximum gap opening at the fracture site by 1.56 times under 45° loading, and 1.58 times under 0° loading. The load on the tension band wire of the 10-mm screw placement was 3.12 times (from 230 to 717 N) higher than that of the 5-mm placement. Under the wire, the contact pressure on the patellar surface was higher with the 10-mm screw placement than the 5-mm screw placement. The peak bone contact pressures with the 10-mm placement were 7.7 times (99.5 to 764 MPa) higher. This is the first numerical study to examine the biomechanical effects of different screw locations on the fixation of a fractured patella using screws and tension band. Based on a higher stability and lower cable tension obtained by the superficial screws placement, the authors recommended the superficial screw placement (5 mm below the leading edge of the patella) rather than the deep screws while fixing the transverse patellar fracture with cannulated screws and cable

Abstract. Background. Aim of this study is to determine the difference between re-operation rates after conventional Methods of fixation of patella fractures using Metallic implants and novel technique of all suture fixation using Ethibond or fiber tape. Methods. This is a retrospective comparative analysis involving 62 patients who had a transverse patellar fracture and underwent surgery between January 2013 to December 2021. Selected patients were divided, based on different fixation methods used, into four groups - TBW group, CC screw group, Encirclage group and Suture Fixation Group. Patients were followed till bone union was evident on radiographs. Number of patients in Metallic implant group undergoing repeat operation were compared with the patients who underwent patella fracture fixation using all suture technique. Mean and standard deviation (SD) were calculated for all continuous variables. Mean of the two groups was compared using unpaired t-test. Results. TBW was the most common method of fixation used in 41(66.1%) patients. 7 patients each underwent surgery using CC screw, Encirclage +/− TBW, and suture fixation respectively. Bone union was seen in about 85% of patients in all the groups suggesting all treatment modalities lead to good fracture healing. 15 patients(36.6%) of patients in TBW group and 3 patients(42.9%) in encirclage group had implant removal because of hardware-related complications (p<0.001). None of the patient who underwent All suture Fixation underwent re-operation. Conclusion. The results suggest that Suture fixation of patellar fractures is a valid treatment modality giving excellent results with similar bone union rates without any complications

Patella fractures constitute 1% of all fractures and may disrupt the extensor mechanism of the knee. The mainstay of treatment for most patella fractures is operative fixation; however, patients with intact extensor mechanisms may be treated with splinting. We describe a series of patients with patella fractures managed non- operatively, without restricted weight bearing or splinting. A consecutive series of 21 patients presenting with a patella fracture to two metropolitan hospitals were included in this study. All patients had an intact extensor mechanism but no distinction was made on age or fracture type. All patients were treated non-operatively with analgesia, were allowed to fully weight-bear and were not splinted. A retrospective review of the case notes was performed and data was collected with phone interview. The main outcome measure was the Western Ontario and McMaster Universities. Osteoarthritis (WOMAC) index, which has a maximum (worst) possible score of 240, and which provides an aggregate score of pain, stiffness and function. Mean time at follow up was 24 months (range 5–49 months). WOMAC scores were excellent (mean=18 of possible maximum 240; range 0–84). Only one patient had a significant complication related to their fracture (deep venous thrombosis), which was detected during hospital admission. Most patients had returned to usual work (9/14). No patients required operative fixation. There was no association between adjusted WOMAC score and age, sex, compensation status, time of follow up, or whether the patient had a significant ipsilateral injury. Patients who had returned to work (p=0.02) or who had lower levels of education (p=0.03) had better WOMAC scores. Management of patella fractures with an intact extensor mechanism does not require restricted weight bearing or splinting

Patella fracture after total knee arthroplasty has a variety of etiologies and has been reported to occur with an incidence ranging from 3% to 21%. Heavy patients with full flexion are at greatest risk for sustaining patella fracture. Overstuffing the patellofemoral joint with an oversized femoral component, an anteriorised femoral component or a femoral component placed in excessive extension can also overload the underlying patella. A similar phenomenon may be seen with underrsection of the patella or use of a thick button. Excessive patellar resection can predispose to patellar fracture as well. It has been demonstrated that a residual patella thickness of less than 15 mm can substantially increase anterior patellar strain. Asymmetric patellar resection can also critically alter the mechanical strength of the patella making it vulnerable to failure. Elevation of the tibiofemoral joint line, from excessive femoral resection and hastened by posterior cruciate ligament release, will result in a relative patella baja. This can cause early patellofemoral articulation, which may result in patellar impingement on the tibial insert in late flexion and ultimately predispose the patella to fracture. Surgical approach and soft tissue dissection should be as atraumatic to the patellar blood supply as possible to preserve the superolateral geniculate artery when performing a lateral retinacular release. The classification used by Goldberg, et al is helpful for planning appropriate intervention:. Type I fractures: Avulsion type fractures generally involving the periphery of the patella without involving the implant. Type II fractures: Disrupt the cement-prosthesis interfaces of the quadriceps mechanism. Type IIIA fractures: Involve the pole of the patella with disruption of the patella ligament. Type IV fractures: Fracture dislocations of the patella. Non-operative treatment is preferred when fractures are non-displaced

Objective. The purpose of the present study was to compare the clinical and radiographic results after TKA using a patellofemoral design modified prosthesis and its predecessor. The other purpose was to investigate whether the use of the recent prosthesis increase the risk of posterior tibial cortex injury or patellar fracture. Materials and Methods. The clinical and radiographic results of 300 knees which underwent TKA using the Attune®prosthesis (group A) were compared with those in a paired match-control group who underwent TKA using the P.F.C. Sigma® prosthesis (group B). The preoperative demographic data between the 2 groups did not differ significantly. The WOMAC, Feller and Kujala scores, and range of motion (ROM) were compared. The minimal distance between the tibial component stem to posterior tibial cortex, and the remnant patella thickness were compared. Results. The postoperative WOMAC score was better in the group A than in the group B (17.7 vs. 18.8, p=0.004). The postoperative ROM was greater in the group A than in the group B (131.4° vs. 129.0°, p=0.008). The postoperative Feller score was not different, but postoperative Kujala score was better in the group A. The minimal distance between the tibial component stem and posterior tibial cortex was significantly shorter in group A than in the group B (6.3mm vs 7.0mm, p<0.001). The proportion of high risk group for posterior tibial cortical injury, which had the minimal distance less than 4mm, was higher in the group A (20.0% vs 10.7%, p=0.002). The remnant patella was thinner in the group A than in the group B (14.8mm vs 15.7mm, p<0.001). The proportion of high risk group for patella fracture with remnant thickness of <12mm was higher in the group A (7.5% vs 2.1%, p=0.003). Conclusion. When comparing the clinical and radiographic results after TKA using the two prostheses of a design modified prosthesis and its predecessor, TKA using the recent prosthesis provided better satisfactory results. However, the risk of injury in the posterior cortex of the tibial metaphysis or remnant patella should be considered in this design modified prosthesis. Level of Evidence. Level III

MPFL reconstruction has demonstrated a very high success rate with improved patella stability, physical function, and patient-reported outcomes. However technical error and a lack of consideration of anatomic risk factors have been shown to contribute to failure after MPFL reconstruction. Previous research has also reported a complication rate of 26% following surgery. The purposes of this study were to determine the re-dislocation rate, type and number of complications, and most common additional surgical procedures following MPFL reconstruction. Patients with symptomatic recurrent patellofemoral instability underwent an MPFL reconstruction (n = 268) and were assessed with a mean follow-up of 31.5 months (minimally 24-months). Concomitant procedures were performed in addition to the MPFL reconstruction in order to address significant anatomic or biomechanical characteristics. Failure of the patellofemoral stabilization procedure was defined as post-operative re-dislocation of the patella. Rates of complications and re-procedures were assessed for all patients. The re-dislocation rate following MPFL reconstruction was 5.6% (15/268). There were no patella fractures. A total of 49/268 patients (18.3%) returned to the operating room for additional procedures following surgery. The most common reason for additonal surgery was removal of symptomatic tibial tubercle osteotomy hardware in 24/268 patients (8.9%). A further 9.3% of patients underwent addtional surgery including revision MPFL reconstruction: with trochleoplasty 8/268 (3.0%), with tibial tubercule osteotomy 4/286 (1.5%) and with femoral derotation osteotomy 3/268 (1.1%); manipulation under anaesthesia for reduced knee range of motion 4/268 (1.5%); knee arthroscopy for pain 8/268 (3.0%); and cartilage restoration procedures 3/268 (1.1%). There was 1 case of wound debridement for surgical incision infection. MPFL reconstruction using an a la carte approach to surgical selection demonstrated a post-operative redislocation rate of 5.6%. The rate of complications following surgical stabilization was low, with the most common reason for additional surgery being removal of hardware

Medial patellofemoral ligament (MPFL) reconstruction is an effective procedure to address patellofemoral instability, however there remains no clear consensus on the optimum technique. Variations in patella tunnel and the use of patella fixation devices are reported in the literature, as are the associated complications of patella fracture and hardware irritation. We present the early results using a two tunnel, Endobutton free technique. 24 MPFL reconstructions (14 female, 10 male) were performed by a single surgeon, using two 3.5mm medial patellar tunnels exiting anteriorly and a looped, extra-synovial hamstring autograft. Femoral fixation was achieved using an non-absorbable interference screw. Mean age was 25.5 years, with a mean follow-up of 21.7 months. Mean Kujala scores were 60.8 preoperatively and 87.9 postoperatively (p<0.0001). No patient experienced further dislocation or patella fracture post-operatively. One patient required interference screw removal. The surgical technique presented has outcomes comparable with the literature. It requires a shorter tendon graft, and removes the need for a patellar fixation device, reducing potential irritation and cost

General Principles. All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue. Acute tibial tuberosity avulsion. Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6 to 8 weeks of immobilization. Augmentation with a semitendinosus graft or Marlex mesh can provide additional support. Acute Patella Tendon Rupture. End-to-end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length, if needed. Acute Quadriceps Tendon Rupture. These can be repaired end-to-end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct. Patella Fracture. Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20-degree lag, non-operative treatment in extension. A loose component and/or > 20-degree extensor lag requires ORIF +/− component revision. Chronic Disruptions. While standard repair techniques are possible, tissue retraction usually prevents a “tension-free” repair. If the patella remains viable and has not retracted proximally an Achilles tendon graft is appropriate. In chronic disruptions with loss of the patella, allograft extensor mechanism reconstruction may be considered. Marlex mesh repair has also been shown to be effective in reconstruction of chronic patellar and quadriceps tendon defects

General Principles: All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex Mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue. Acute tibial tuberosity avulsion: Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6 to 8 weeks of immobilization. Augmentation with a semitendinosus graft or Marlex can provide additional support. Acute Patella Tendon Rupture: End-to-end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length, if needed. Acute Quadriceps Tendon Rupture: These can be repaired end-to-end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct. Patella Fracture: Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20-degree lag, non-operative treatment in extension. A loose component and/or > 20-degree extensor lag requires ORIF +/− component revision. Chronic Disruptions: While standard repair techniques are possible, tissue retraction usually prevents a “tension-free” repair. If the patella remains viable and has not retracted proximally an Achilles tendon graft is appropriate. In chronic disruptions with loss of the patella, allograft extensor mechanism reconstruction may be considered. Marlex mesh repair has also been shown to be effective in reconstruction of chronic patellar and quadriceps tendon defects

Extensor mechanism complications after or during total knee arthroplasty are problematic. The prevalence ranges from 1–12% in TKR patients. Treatment results for these problems are inferior to the results of similar problems in non-TKR patients. Furthermore, the treatment algorithm is fundamentally different from that of non-TKR patients. The surgeon's first question does not focus on primary fixation; rather the surgeon must ask if the patient needs surgery and if so am I prepared to augment the repair? Quadriceps tendon rupture, periprosthetic patellar fracture, and patellar tendon rupture have similar treatment algorithms. Patients who are able to perform a straight leg raise and have less than a 20-degree extensor lag are generally treated non-operatively with extension bracing. The remaining patients will need surgical reconstruction of the extensor mechanism. Loose patellar components are removed. Primary repair alone is associated with poor results. Whole extensor mechanism allograft, Achilles tendon allograft, and synthetic mesh reconstruction are the current techniques for augmentation. In the acute setting if these are not available hamstring tendon harvest and augmentation is an option. Achilles tendons and synthetic mesh are easier to obtain than and entire extensor mechanism but are limited to patients that have an intact patella and the patella that can be mobilised to within 2–3 cm of the joint line. No matter which technique is used the principles are: rigid distal/tubercle fixation, coverage of allograft/mesh with host tissue to decrease infection, tensioning the augment material in extension, no flexion testing of reconstruction and post-operative extension bracing

Introduction. Although total knee arthroplasty (TKA) in end-stage hemophilic arthropathy can reduce the severe joint pain and improve the functional disability, it is technically demanding. In addition, it has generally reported a high rate of complication including periprosthetic joint infection (PJI) and component loosening up to 20%. Although the Knee Society classification system of TKA complication was introduced, the complications of TKA in hemophilic arthropathy has not stratified using this classification system in previous articles to the best of our knowledge. The purpose of this study was to evaluate the mid-term outcomes and complications of TKA in hemophilic arthropathy. Methods. The study retrospectively reviewed 131 consecutive primary TKAs (102 patients) in single institute. The mean patient age was 41.0 years and mean follow-up time was 6.4 years. The clinical and radiographic results were evaluated. The complications were categorized according to the classification system of the Knee Society for TKA complications. Results. The average WOMAC score improved from 66.0 to 24.2. The average flexion contracture significantly decreased from 17.3° to 4.7°, but the average pre and postoperative maximum flexion did not differ (80.9 ° vs. 85.6°). The average mechanical axis was varus 5.2° preoperatively and valgus 0.3° postoperatively. The coronal position of femoral and tibial components and sagittal position of those components were within ±3° in 83.2%, 89.3%, 63.4%, and 73.3%. The complications occurred in 17 knees (13.0%). There were 7 bleeding and hemarthrosis. Five knees were treated with increased amounts of coagulation factor concentrate and two knees were treated with incision and drainage of hematoma. One medial collateral ligament injury of grade 2 required change of postoperative rehabilitation protocol and bracing. Two stiffness of grade 3 required unplanned admission and manipulation under anesthesia. Three deep PJI were treated with 2 stage revision TKA. There were 4 periprosthetic fractures. Three distal femur fractures were treated with open reduction and internal fixation for 3 knees. One patellar fracture was healed with conservative treatment. Conclusions. The mid-term results of TKA in end-stage hemophilic arthropathy were satisfactory with obtaining pain relief, improving function, and decreasing flexion contracture. Bleeding and PJI continues to be a major concern for TKA in patients with hemophilic arthropathy, and risk of periprosthetic fracture has to be taken into account for patient education and appropriate prevention. Level of evidence. Level IV

General Principles - All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex Mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue. Acute Tibial Tuberosity Avulsion - Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6 to 8 weeks of immobilisation. Augmentation with a semitendinosus graft or Marlex can provide additional support. Acute Patella Tendon Rupture - End-to-end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length, if needed. Acute Quadriceps Tendon Rupture - These can be repaired end to end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct. Patella Fracture - Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20-degree lag. A loose component and/or >20-degree extensor lag requires ORIF +/− component revision. Chronic Disruptions - While standard repair techniques are possible, tissue retraction usually prevent a “tension-free” repair. If the patella remains viable and has not retracted proximally an Achilles tendon graft is appropriate while in any patellar tendon defect, mesh repair has been shown to be effective. In most chronic disruptions with loss of the patella allograft extensor mechanism reconstruction may be considered

Extensor mechanism complications after or during total knee arthroplasty (TKA) are problematic. The prevalence ranges from 1%-12% in TKA patients. Treatment results for these problems are inferior to the results of similar problems in non-TKA patients. Furthermore, the treatment algorithm is fundamentally different from that of non-TKA patients. The surgeon's first question does not focus on primary fixation; rather the surgeon must ask if the patient needs surgery and if so am I prepared to augment the repair? Quadriceps tendon rupture, peri-prosthetic patellar fracture, and patellar tendon rupture have similar treatment algorithms. Patients who are able to perform a straight leg raise and have less than a 20-degree extensor lag are generally treated non-operatively with extension bracing. The remaining patients will need surgical reconstruction of the extensor mechanism. Loose patellar components are removed. Primary repair alone is associated with poor results. Whole extensor mechanism allograft, Achilles tendon allograft, and synthetic mesh reconstruction are the current techniques for augmentation. In the acute setting if these are not available, hamstring tendon harvest and augmentation is an option. Achilles tendons and synthetic mesh are easier to obtain than an entire extensor mechanism but are limited to patients that have an intact patella and the patella that can be mobilised to within 2–3 cm of the joint line. No matter which technique is used the principles are: rigid distal/tubercle fixation, coverage of allograft/mesh with host tissue to decrease infection, tensioning the augment material in extension, no flexion testing of reconstruction and post-operative extension bracing

General Principles. All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex Mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue. Acute tibial tuberosity avulsion. Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6–8 weeks of immobilization. Augmentation with a semitendinosus graft or Marlex can provide additional support. Acute Patella Tendon Rupture. End to end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length, if needed. Acute Quadriceps Tendon Rupture. These can be repaired end to end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct. Patella Fracture. Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20-degree lag. A loose component and/or >20-degree extensor lag requires ORIF +/− component revision. Chronic Disruptions. While standard repair techniques are possible, tissue retraction usually prevents a “tension-free” repair. In most chronic disruptions allograft extensor mechanism reconstruction is preferable. If the patella remains viable and has not retracted proximally, an Achilles tendon graft is appropriate while in any patellar tendon defect, mesh repair has been shown to be effective

Management of the patella with poor bone stock remains a challenge in revision total knee arthroplasty (TKA). The purpose of this study was to evaluate the results of a novel surgical technique in which widely available wires and acrylic bone cement are used in the reconstruction of a deficient patella. Twenty-eight patients (30 knees) underwent revision TKA in which a deficient patella was treated with an onlay-type prosthesis and bone-augmenting procedure, using transcortical wiring. The technique was indicated when the thickness of remnant patella was less than 8mm with variable amounts of the peripheral rim. The remaining patellar height ranged from 3.2mm to 7.3mm. Follow-up was available for all patients with a mean of 36.6 months (range, 24 to 55 months). The respective mean Knee Society scores for knee and function improved from 34.2 points (range, 18 to 65 points) and 23 points (range, 18 to 46 points) preoperatively to 73.5 points (range, 30 to 88 points) and 61points (range, 34 to 80 points) at final follow-up. The mean thickness of the patellar construct was 14.6mm (range, 12.2 – 18.3mm). One patient experienced patellar fracture during knee flexion one week after surgery. There were no complications associated with implanted hardware. A patellar bone-augmenting procedure using transcortical wiring is a straightforward technique that potentially allows firm fixation. Considering the satisfactory short- to mid-term results, we believe that this technique provides a good alternative option in addressing this challenging problem in revision TKA

Background. Management of the patella with poor bone stock remains a challenge in revision total knee arthroplasty (TKA). The purpose of this study was to evaluate the results of a novel surgical technique in which widely available wires and acrylic bone cement are used in the reconstruction of a deficient patella. Methods. Twenty-eight patients (30 knees) underwent revision TKA in which a deficient patella was treated with an onlay-type prosthesis and bone-augmenting procedure, using transcortical wiring. The technique was indicated when the thickness of remnant patella was less than 8mm with variable amounts of the peripheral rim. The remaining patellar height ranged from 3.2mm to 7.3mm. Follow-up was available for all patients with a mean of 36.6 months (range, 24 to 55 months). Results. The respective mean Knee Society scores for knee and function improved from 34.2 points (range, 18 to 65 points) and 23 points (range, 18 to 46 points) preoperatively to 73.5 points (range, 30 to 88 points) and 61points (range, 34 to 80 points) at final follow-up. The mean thickness of the patellar construct was 14.6mm (range, 12.2 – 18.3mm). One patient experienced patellar fracture during knee flexion one week after surgery. There were no complications associated with implanted hardware. Conclusions. A patellar bone-augmenting procedure using transcortical wiring is a straightforward technique that potentially allows firm fixation. Considering the satisfactory short- to mid-term results, we believe that this technique provides a good alternative option in addressing this challenging problem in revision TKA

Introduction. Anterior knee pain (AKP) is a recognized cause of patient's dissatisfaction after total knee arthroplasty. Potential implant/technique related contributors to AKP are patellofemoral maltracking, trochlear geometry, femoral malrotation, patellar tilt and overstuffing. The primary aim of this prospective, matched pair study was to assess the safety, efficacy and performance of an anatomic patella and its effect on AKP in in a matched pair analysis. Material and Methods. Between July 2012 and May 2013, 55 consecutive posterior stabilized cemented Attune TKAs (Depuy) were matched to the PFC Sigma group based on age, gender, and body mass index (BMI). All surgeries were performed via medial parapatellar approach with patellar resurfacing. Clinical and radiographic analysis was performed prospectively with minimum 6 month follow-up. Radiographic measurements included overall limb alignment, anterior offset, posterior offset, joint line, patellar thickness, patellar tilt and patellar displacement by two independent observers. Results. The mean functional outcomes were similar in both groups. AKP incidence between Attune and PFC was statistically insignificant (3.6% and 3.8%). Radiographic analysis revealed no mal-alignment, or osteolysis. No complications such as infection, patellar fracture, subluxation or dislocations were observed. Discussion. Attune knee design demonstrates excellent short-term safety and efficacy. At minimum 6-month follow-up, anatomical patella with shows less AKP than single radius patella design. Longer follow-up is required to assess functional outcome this design

General Principles: All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex Mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue. Acute tibial tuberosity avulsion: Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6–8 weeks of immobilization. Augmentation with a semitendinosus graft or Marlex can provide additional support. Acute Patella Tendon Rupture: End-to-end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length if needed. Acute Quadriceps Tendon Rupture: These can be repaired end-to-end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct. Patella Fracture: Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20 degree lag. A loose component and/or > 20 degree extensor lag requires ORIF +/− component revision. Chronic Disruptions: While standard repair techniques are possible, tissue retraction usually prevents a “tension-free” repair. In most chronic disruptions allograft extensor mechanism reconstruction is preferable. If the patella remains viable and has not retracted proximally an Achilles tendon graft is appropriate while in any patellar tendon defect, mesh repair has been shown to be effective