Introduction: Recurrent Instability of the hip remains a difficult problem to treat successfully. The Posterior Lip Augmentation Device (PLAD) is a useful option where there is no gross mal-orientation of the components. Methods: A retrospective single surgeon review was performed to identify patients who had undergone application of a PLAD to treat recurrent instability. Patients with less than 12 months follow up were excluded. Results: 14 patients were identified with an average age of 75.5 years (Range 59 – 90 years). There were 7 cases of trochanteric non-union as a result of previous surgery. The mean follow up was 26 months (Range 13 – 41 months). In 13 patients there have been no further instances of dislocation. 1 patient went on to dislocate again and has now undergone a socket revision. Conclusion: Application of the Posterior Lip Augmentation Device is a well tolerated procedure with very favourable success rates (93%). Given the limited morbidity and short operating time associated with this surgical option it provides a predictable outcome in cases where the original components are well orientated and securely fixed

This study reports the outcome of using the Posterior Lip Augmentation Device (PLAD) for recurrent dislocation of total hip replacement. Twenty-seven patients (16 in Inverness, 11 in Leeds) were treated with the device. The indication for its use was recurrent dislocation of the hip in a patient who had a well-orientated and well-fixed cemented acetabular component. The patients had had between 2 and 14 dislocations before using the PLAD. 24 of the 27 patients had satisfactory control of the dislocations after surgery. The operation was found to be straightforward in most cases with few complications, although one case in the Inverness series has a partial sciatic nerve palsy which is recovering. Of the three failures, two had recurrent dislocation after the use of the PLAD. In one of these, in whom the dislocation followed acetabular reconstruction with impaction grafting, the cup also pulled out due to the semi-captive state after use of the PLAD. Both of these cases were treated by a Girdlestone excision arthroplasty. There was one final failure in whom there has been no further dislocation but following an abduction injury some four months after surgery, progressive cup loosening developed and he awaits revision of the cup. One patient complains of an occasional click in the hip joint and a broken screw is visible on x-ray but there has been no loss of position of the device and no further evidence of dislocation. Overall, we have found that this device gives satisfactory control of recurrent dislocations of the hip but the failures have stressed the need to ensure that the cup fixation is sound before inserting the device

Aims: To review the effectiveness of the Posterior Lip Augmentation Device (P.L.A.D.) in treating recurrent prosthetic total hip dislocation. Method: We reviewed 36 patients from 2 hip revision surgeons from 2 UK centres who underwent cup augmentation using this device since October 1995. Data were collected from case notes, X-rays and clinical review. All dislocations were posterior (minimum of 3 dislocations). In the majority of cases the abductors were poor or detached, and 35 of the 36 patients had undergone at least one major operation on their hip before a P.L.A.D. was þtted (mean 2.2 operations). Results: The mean age at the time of P.L.A.D. was 73 years (range 47–94). The longest P.L.A.D. follow up is 72 months, and is working well without problems reported by the patient or visible changes on x-ray. A total of 26 out of 36 patients (72.2%) have had a successful correction of their dislocation over this mean period of 21 months (range 8 days Ð 72 months). 10 patients (27.8%) developed signiþcant problems of which 7 (19.4%) required removal of the implant. There were 4 unrelated deaths in our cohort. Conclusions: We feel it has a place in the treatment of recurrent dislocation, particularly in the frail patient, with well-þxed and orientated components, where risks of revision surgery are high and there will be less loading postoperatively

Recurrent posterior dislocation is a recognised complication following primary total hip arthroplasty. Incidences of between 0.11% and 4.5% have been reported in the literature. Component revision is regarded as standard management of recurrent posterior dislocation. However, revision surgery is a major surgical procedure and is often unsuitable for elderly, frail patients. A congruent, ultra-high molecular weight polyethylene acetabular augment with a stainless steel backing plate has been developed. This can be inserted providing there is no malalignment, wear or loosening of the primary components. In this study we compared twenty patients who underwent conventional revision surgery to twenty patients who had a PLAD inserted for recurrent posterior dislocation following primary Charnley total hip arthroplasty. Both groups were age and sex-matched and the average number of dislocations prior to surgery was three for each group. For the PLAD group, the mean operative time, the mean intraoperative blood loss, the time spent in HDU, the transfusion requirements and the duration of hospital stay was significantly less than that for the revision group. Furthermore, there was no significant difference in the Oxford Hip Score recorded preoperatively and at 6 weeks, 6 months, one year and two years following surgery. None of the patients had sustained a further dislocation at latest review. We conclude that the Posterior Lip Augmentation Device is a safe and effective option in the management of patients with recurrent posterior hip dislocation when there is no evidence of component failure or gross malposition

Introduction: Reported incidence of dislocation following dislocation of hip replacements varies from less than 1% to 8%, the majority (59%) being in the first 3 months and 77% within a year. Recurrent dislocation of total hip arthroplasty is a serious problem for both patient and surgeon. Revision of the components does not guarantee success and there is significant comorbidity associated with major revision surgery. Early techniques of cup augmentation were complicated by screw and augment failure, hence cup augmentation evolved into a low profile polyethylene wedge with a separate metal backing and five screw fixation called the Posterior Lip Augmentation device (PLAD). Methods: 33 patients in Leeds and Inverness underwent PLAD placement between 1995 and 2000. They were followed up at a minimum of 5 years postoperatively (5–9 years). Where patients had died the cause of death and status of the PLAD at time of death was determined from the notes. Results: The mean age at time of PLAD insertion was 73 years(43–94). The longest survival was 102 months, the shortest 8 days. Of the 33 patients undergoing PLAD insertion, 3 were lost to follow up, 13 had died by the time of follow up, 7 had been revised and 10 had survived revision free. Discussion: When considering the revision as an end point, PLAD insertion compares favourably with total revision. As shown by the mortality of the patients in the cohort, a less invasive option for the patient with significant comorbidities is useful to have in the surgical armamentarium

Recurrent dislocation of the hip is a difficult management problem. We have chosen to tackle this in a minimal way and avoid complex revisions. All patients were late dislocators, and the majority were older than 75 years with 4 patients being octogenarians.

A 7cm incision is made in the skin at the trochanter, the fascia is opened and the hip dislocated posteriorly the head of the hip is felt under the external rotators and they are opened in a minimal way. The cup is inspected for gross wear, no abnormality has been found. The PLAD is applied and fixed posteriorly after removal of minimal capsular and scar tissue, simple closure takes place with no drain.

This procedure has been performed on nine occasions in our unit and all cases remain successful at a mean followup of 18 months (2–35 months). Operation times varied between 28 –42 minutes (mean 36 mins). Blood loss is minimal. The patient can be mobilised right away and early discharge can be achieved. This technique seems an ideal management solution in and elderly population with a good cup and stem with recurrent dislocation for unknown cause.

Aims

The aim of this study was to identify the optimal lip position for total hip arthroplasties (THAs) using a lipped liner. There is a lack of consensus on the optimal position, with substantial variability in surgeon practice.

During surgical reduction of ankle injuries with syndesmotic instability surgeons often use the anteroposterior (AP) and mortise radiographs to assess reduction. Current literature predicts 50% are malreduced mainly in the sagittal plane. Our aim was to develop a radiographic measure based on the lateral view to assess both the normal and abnormal fibula/tibia relationship after simulated syndesmotic malreduction and to evaluate the effect on commonly used AP and mortise measurements. Nine fresh-frozen cadaveric specimens were dissected to the level of the syndesmosis. AP, mortise and talar dome lateral radiographs were obtained before and following syndesmosis division and posterior fibula displacement. On the lateral radiograph a line was drawn (Orthoview) from the anterior border of the fibula bisecting a line drawn from the anterior to posterior lips of the distal tibia. The ratio of the anterior-posterior segments was calculated. Also a line was drawn from the posterior border of the fibula and the distance was measured to the posterior lip of the tibia. At 0, 2, 4 and 6mm of displacement the ratio measured 1.3±0.2, 1.1±0.2, 0.9±0.2 and 0.7±0.2 respectively with all pairwise comparisons being significantly different. Inter- and intra-observer variability varied from substantial to perfect. The only significant medial clear space (MCS) difference was on the mortise view between 0mm (2.0±0.3mm) and 6mm (2.4±0.4mm) displacement. Our new measure of syndesmotic reduction is reproducible and can detect from 2mm of saggital fibular displacement. At maximum fibular displacement the increase in MCS was less than 1mm. This demonstrates standard mortise radiographs are poor at detecting syndesmotic reduction. An interesting observation was in all specimens prior to any displacement, the posterior fibular line always bisected the posterior lip of the tibia or lay just anterior to it, never posterior. This could serve as a useful adjunct for surgeons when assessing syndesmotic reduction intra-operatively

Tibial plateau fracture reduction involves restoration of alignment and articular congruity. Restorations of sagittal alignment (tibial slope) of medial and lateral condyles of the tibial plateau are independent of each other in the fracture setting. Limited independent assessment of medial and lateral tibial plateau sagittal alignment has been performed to date. Our objective was to characterize medial and lateral tibial slopes using fluoroscopy and to correlate X-ray and CT findings. Phase One: Eight cadaveric knees were mounted in extension. C-arm fluoroscopy was used to acquire an AP image and the C-arm was adjusted in the sagittal plane from 15° of cephalad tilt to 15 ° of caudad tilt with images captured at 0.5° increments. The “perfect AP” angle, defined as the angle that most accurately profiled the articular surface, was determined for medial and lateral condyles of each tibia by five surgeons. Given that it was agreed across surgeons that more than one angle provided an adequate profile of each compartment, a range of AP angles corresponding to adequate images was recorded. Phase Two: Perfect AP angles from Phase One were projected onto sagittal CT images in Horos software in the mid-medial compartment and mid-lateral compartment to determine the precise tangent subchondral anatomic structures seen on CT to serve as dominant bony landmarks in a protocol generated for calculating medial and lateral tibial slopes on CT. Phase Three: 46 additional cadaveric knees were imaged with CT. Tibial slopes were determined in all 54 specimens. Phase One: Based on the perfect AP angle on X-ray, the mean medial slope was 4.2°+/-2.6° posterior and mean lateral slope was 5.0°+/-3.8° posterior in eight knees. A range of AP angles was noted to adequately profile each compartment in all specimens and was noted to be wider in the lateral (3.9°+/-3.8°) than medial compartment (1.8°+/-0.7° p=0.002). Phase Two: In plateaus with a concave shape, the perfect AP angle on X-ray corresponded with a line between the superiormost edges of the anterior and posterior lips of the plateau on CT. In plateaus with a flat or convex shape, the perfect AP angle aligned with a tangent to the subchondral surface extending from center to posterior plateau on CT. Phase Three: Based on the CT protocol created in Phase Two, mean medial slope (5.2°+/-2.3° posterior) was significantly less than lateral slope (7.5°+/-3.0° posterior) in 54 knees (p<0.001). In individual specimens, the difference between medial and lateral slopes was variable, ranging from 6.8° more laterally to 3.1° more medially. In a paired comparison of right and left knees from the same cadaver, no differences were noted between sides (medial p=0.43; lateral p=0.62). On average there is slightly more tibial slope in the lateral plateau than medial plateau (2° greater). However, individual patients may have substantially more lateral slope (up to 6.8°) or even more medial slope (up to 3.1°). Since tibial slope was similar between contralateral limbs, evaluating slope on the uninjured side provides a template for sagittal plane reduction of tibial plateau fractures

Introduction:. While kinematic abnormalities of contemporary TKA implants have been well established, a solution has not yet been achieved. We hypothesized that contemporary TKA implants are not compatible with normal soft-tissue function and normal knee motion. We propose a novel technique for reverse engineering advanced implant articular surfaces (biomimetic surface), by using accurate 3D kinematics of normal knees. This technique accounts for surgical placement of the implants, and allows design of tibial and femoral articular surfaces in conjunction. Methods:. Magnetic resonance imaging was used to create 3D knee models of 40 normal subjects (24 male, 16 female, age 29.9 ± 9.7 years), and bi-planar fluoroscopy was used to capture 3D knee motion during a deep knee bend. These data were combined to create a 3D virtual representation of an average normal knee and its motion pathway. A TKA femoral component was mounted on the average knee, and moved through its normal kinematic pathway to carve out an articular surface from a tibial template (Fig. 1 and 2). The geometry of the resulting biomimetic tibia was compared to that of the native tibia, and a contemporary TKA tibial insert that uses the same femoral component. Results:. The biomimetic tibia had a dished medial plateau and a convex lateral plateau similar to the native tibia, with anterior/posterior lips analogous to the native menisci (Fig. 3). The anterior/posterior lips were carved by the femoral component at its end points in extension and full flexion (Fig. 2). In contrast, while the medial geometry of the contemporary TKA tibia was similar to the biomimetic tibia, the lateral geometry was significantly different (Fig. 3). Anteriorly, the contemporary tibia was excessively proud. The resulting soft-tissue tightening would prevent anterior location of lateral femoral condyle in extension, and block screw home femoral rotation. Posteriorly, again the contemporary tibia was excessively proud. The resulting soft-tissue tightening would prevent posterior rollback of the lateral femoral condyle in flexion. Conclusion:. The non-anatomic geometry of the contemporary TKA tibia, especially on the lateral side, conflicted with normal knee motion. In contrast, a biomimetic tibia reverse engineered directly from normal knee motion, had an anatomic geometry, with anterior/posterior lips similar to the native menisci. Such a biomimetic surface would allow normal soft tissue function and normal knee motion. The reverse engineering technique described herein enables for the first time, the direct use of in vivo knee kinematics to generate advanced implant articular surfaces

Introduction. Modern implant systems offer a variety of options to address the posterior cruciate ligament (PCL) and afford stability in primary total knee arthroplasty (TKA). One system has three bearing options for cruciate retaining (CR) TKA: standard CR bearing (CR-S) with 3° posterior slope and no posterior lip; CR lipped bearing (CR-L) with no slope and small posterior lip, and deep-dished anterior stabilized bearing (CR-AS) with large anterior build-up to compensates for deficient or lax PCL. We previously reported on 1940 patients (2449 CR-TKA) at early follow-up comparing these three CR bearings and found CR-AS bearings had greater improvement in ROM and lower rate of manipulation despite their use in patients with greater preoperative deformity and lower ROM. The purpose of this study was to review a broader series by a single surgeon-designer with minimum 2-year follow-up to determine if there were differences between bearing types in terms of clinical outcomes and survival. Methods. From 2003 to 2014, 3348 patients (4500 knees) underwent primary CR-TKA and were available for review with minimum 2-year follow-up. An algorithmic approach to constraint was employed, choosing the least amount necessary to afford stability. Bearings used were 3883 CR-S (86%), 256 CR-L (6%), and 361 CR-AS (8%). CR-S bearings were used in patients with less preoperative tibiofemoral deformity (p=0.0316), less flexion contracture (p<0.0001), and better ROM (p<0.0001), but more mediolateral instability (p<0.0001) than CR-AS bearings. Results. Mean follow-up overall was 5.7 years (range, 2–14). Overall 106 TKA (2.4%) have been revised (46 fully, 56 partial, 4 unknown). Indications for revision were instability in 40 (all CR-S), 28 infection, 10 aseptic loosening, 8 arthrofibrosis, 7 periprosthetic fracture, 3 extensor related, 2 heterotopic ossification, 3 pain, and 5 other or unknown. Chi-squared analysis showed no difference between bearing groups for overall revision (p=0.1724). However, revision for instability was greater for CR-S (1.0%) versus CR-AS bearings (p=0.0454, Fisher's exact). Frequency of manipulation was no different between bearing groups (p=0.8512). CR-AS patients had greater improvement than CR-S patients in ROM (4.4° versus 1.6°, p=0.0003), and Knee Society pain (39.3 versus 35.9, p=0.0002), clinical (53.5 versus 47.0, p<0.0001), and function (18.9 versus 16.0, p=16.0). CR-L patients had greater improvement than CR-S in pain (38.2, p=0.0367) and clinical score (53.6, p<0.0001). Discussion. In this large single surgeon series, Kaplan-Meier survival free of any revision was similar between bearing groups and excellent overall with 96.0% (±0.49%) at 14.1 years. No revisions for instability were observed with CR-L or CR-AS bearings, but were the most frequent cause of revision with CR-S bearings. Manipulation rates were similar between bearing groups. ROM, pain, clinical, and functional improvements were greater with a deep-dished, anterior-stabilized bearing

Glenoid exposure is the name of the game in total shoulder arthroplasty. I can honestly say that it took me more than 5 years but less than 10 to feel confident exposing any glenoid, regardless of the degree of bone deformity and the severity of soft-tissue contracture. This lecture represents the synthesis of my experience exposing some of the most difficult glenoids. The basic principles are performing extensive soft-tissue release, minimizing the anteroposterior dimension of the humerus by osteophyte excision, making an accurate humeral neck cut, having a plethora of glenoid retractors, and knowing where to place them. The ten tips, in reverse order of importance are: 10.) Tilt the table away from operative side—this helps face the surface of the glenoid, especially in cases of posterior wear, toward the surgeon. 9.) Have multiple glenoid retractors—these include a large Darrach, a reverse double-pronged Bankart, one or two blunt Homans, small and large Fukudas. 8.) Remove all humeral osteophytes before attempting to retract the humerus posteriorly to expose the glenoid—this helps to decrease the overall anteroposterior dimension of the humerus and allows for maximum posterior displacement of the humerus. 7.) Make an accurate humeral neck cut—even 5mm of extra humeral bone will make glenoid exposure difficult. 6.) Optimal humeral position—it has been taught that abduction, external rotation, and extension is the optimal position. It may vary with each case. Therefore, experiment with humeral rotation to find the position that allows maximum visualization. This is often the position that makes the cut surface of the humerus parallel to the surface of the glenoid. 5.) Optimal retractor placement—my typical retractor placement is a Fukuda on the posterior lip of the glenoid, a reverse double-pronged Bankart on the anterior neck of the scapula, and a blunt Homan posterosuperiorly. Occasionally, a second blunt Homan anteroinferiorly is helpful, particularly in muscular males with a large pectoralis major. 4.) Laminar spreader for lateral humeral displacement—this can be helpful for posterior capsulorrhaphy or for posterior glenoid bone grafting. 3.) Maximal humeral capsular release—the release of the anterior capsule from the humerus must go well past the 6 o'clock position and up the posterior surface of the humerus. This aides in humeral exposure but also allows for more posterior displacement of the humerus during glenoid exposure. 2.) Anteroinferior capsular release or excision—extensive anteroinferior release or excision (my preference), allows for maximal posterior humeral displacement and also restores external rotation. 1.) Posterior or posteroinferior capsular release—release of the posteroinferior corner of the capsule from the glenoid results in a noticeable increase in posterior humeral retractability. In cases without substantial posterior subluxation, extensive release of the entire posterior capsule is performed

Background. To prevent excessive tension on the posterior cruciate ligament (PCL) in cruciate-retaining total knee arthroplasty (CR-TKA), some knee prosthesis-systems offer the option of creating a posterior slope for the tibial polyethylene insert. Vanguard® Complete Knee System offers two different types of tibial bearing for CR. -TKA. CR Lipped Bearing (LB) has a slightly raised posterior lip, whereas CR Standard Bearing (SB) is recessed downward at the posterior margin and has 3° posterior slope. The objective of this study was to investigate the effect of the tibial bearing slope on PCL load using the original devise in vivo conditions. Material and Methods. Twenty osteoarthritic varus knees were included in this study. After implantation of the trial components, PCL stiffness was measured using the original tension analyzer intra-operatively. Elastic modulus of PCL was calculated at 90 and 120 degrees knee flexion on two types of bearing surface. Results. Elastic modulus of PCL was 7.2±0.9 N/mm (mean±SE) at 90 degrees knee flexion, and 9.5±1.1 N/mm (mean±SE) at 120 degrees knee flexion with the Lipped Bearing (no slope). With the Standard Bearing (3 degrees posterior slope), elastic modulus decreased to 6.0±0.5 N/mm (mean±SE) at 120 degrees knee flexion. Discussion and Conclusion. Higher PCL stiffness was observed at 120 degrees knee flexion than 90 degrees knee flexion with Lipped Bearing surface (no slope), but using the Standard Bearing (3 degrees posterior slope), PCL stiffness decreased significantly at 120 degrees knee flexion. Therefore a posterior tibial slope of bearing insert prevents an excessive load on PCL at high knee flexion angles

Glenoid exposure is the name of the game in total shoulder arthroplasty. I can honestly say that it took me more than 5 years but less than 10 to feel confident exposing any glenoid, regardless of the degree of bone deformity and the severity of soft-tissue contracture. This lecture represents the synthesis of my experience exposing some of the most difficult glenoids. The basic principles are performing extensive soft-tissue release, minimizing the anteroposterior dimension of the humerus by osteophyte excision, making an accurate humeral neck cut, having a plethora of glenoid retractors, and knowing where to place them. The ten tips, in reverse order of importance are: 10.) Tilt the table away from operative side—this helps face the surface of the glenoid, especially in cases of posterior wear, toward the surgeon. 9.) Have multiple glenoid retractors—these include a large Darrach, a reverse double-pronged Bankart, one or two blunt Homans, small and large Fukudas. 8.) Remove all humeral osteophytes before attempting to retract the humerus posteriorly to expose the glenoid—this helps to decrease the overall anteroposterior dimension of the humerus and allows for maximum posterior displacement of the humerus. 7.) Make an accurate humeral neck cut—even 5mm of extra humeral bone will make glenoid exposure difficult. 6.) Optimal humeral position—it has been taught that abduction, external rotation, and extension is the optimal position. It may vary with each case. Therefore, experiment with humeral rotation to find the position that allows maximum visualization. This is often the position that makes the cut surface of the humerus parallel to the surface of the glenoid. 5.) Optimal retractor placement—my typical retractor placement is a Fukuda on the posterior lip of the glenoid, a reverse double-pronged Bankart on the anterior neck of the scapula, and a blunt Homan posterosuperiorly. Occasionally, a second blunt Homan anteroinferiorly is helpful, particularly in muscular males with a large pectoralis major. 4.) Laminar spreader for lateral humeral displacement—this can be helpful for posterior capsulorrhaphy or for posterior glenoid bone grafting. 3.) Maximal humeral capsular release—the release of the anterior capsule from the humerus must go well past the 6 o'clock position and up the posterior surface of the humerus. This aides in humeral exposure but also allows for more posterior displacement of the humerus during glenoid exposure. 2.) Anteroinferior capsular release or excision—extensive anteroinferior release or excision (my preference), allows for maximal posterior humeral displacement and also restores external rotation. 1.) Posterior or posteroinferior capsular release—release of the posteroinferior corner of the capsule from the glenoid results in a noticeable increase in posterior humeral retractability. In cases without substantial posterior subluxation, extensive release of the entire posterior capsule is performed. Following these steps will help the surgeon to gain adequate glenoid exposure, even in the most difficult cases

INTRODUCTION. Most total knees today are CR or PS, with lateral and medial condyles similar in shape. There is excellent durability, but a shortfall in functional outcomes compared with normals, evidenced by abnormal contact points and gait kinematics, and paradoxical sliding. However unicondylar, medial pivot, or bicruciate retaining, are preferred by patients, ascribed to AP stability or retention of anatomic structures (Pritchett; Zuiderbaan). Recently, Guided Motion knees have been shown to more closely reproduce anatomic kinematics (Walker; Willing; Amiri; Lin; Zumbrunn). As a design approach we proposed Design Criteria: reproduce the function of each anatomic stabilizing structure with bearing surfaces on the lateral and medial sides and intercondylar; resected cruciates because this is surgically preferred; avoid a cam-post because of central femur bone removal, soft tissue entrapment, noises, and damage (Pritchett; Nunley). Our hypothesis was that these criteria could produce a Guided Motion design with normal kinematics. METHODS & MATERIALS. Numerous studies on stability and laxity showed the ACL was essential to controlling posterior femoral displacement on the tibia whether the knee was loaded or unloaded. Under load, the anterior upwards slope of the medial tibial plateau prevented anterior displacement (Griffen; Freeman; Pinskerova; Reynolds). The posterior cruciate and the downward lateral tibial slope produced lateral rollback in flexion. The Replica Guided Motion knee had 3 bearings (Fig 1). The lateral side was shallow and sloped posteriorly, with a posterior lip to prevent excess displacement. The medial anterior tibial and femoral slopes were increased as in the anatomic knee. In the intercondylar region, a saddle bearing replaced ACL function by controlling posterior femoral displacement. For testing, a typical PS design was used as comparison. A Knee Test Machine (Fig 2) flexed the knee, and applied axial compression, shear and torque to represent a range of functions. Bone shapes were reproduced by 3D printing and collaterals by elastomeric bands. Motion was recorded with a digital camera, and Geomagic to process data. RESULTS. The kinematics of normal knees was the benchmark (Arno). The results for neutral path of motion, and the AP laxity about the neutral path, are shown (Fig 3). The PS showed symmetric motion, with anterior medial sliding and excessive constraint in low and high flexion. For the Replica, the medial condyle remained almost constant, but the lateral side rolled posteriorly with flexion, less than normal to prevent damage to the posterior lateral tibial plastic. The lateral side had similar anterior laxity to anatomic, but more than anatomic in late flexion. Based on 10 parameter motion scoring, the Replica was closer to normal than the PS, 82% cf 51%. DISCUSSION. Functional outcomes after TKA are less than normal, TKA design being a likely factor. The approach shown here is intended to reproduce more anatomic kinematics of neutral path of motion and laxity. Such a Replica Guided Motion knee, based on an anatomic structure/stability approach, could reproduce close to normal kinematics even without the cruciates or a cam-post. This may result in improved functional outcomes, and a closer feeling of a normal knee. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed and widely used. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femoro-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femoro-tibial joint with use of CS polyethylene insert before and after PCL resction using computer assisted navigation system and tensor device intra-operatively in TKA. Materials and Methods. Sixty-one consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. During surgery, using a tensor device, after bony cut of femur and tibia, joint gaps were assessed in 0 and 90 degrees in flexion. Then, CS polyethylene tibial trial insert were inserted after trial implantation of femoral and tibial components, before and after resection of PCL, respectively. The kinematic parameters of the soft-tissue balance, and amount of coronal and sagittal relative movement between femur and tibia were obtained by interpreting kinematics, which display tables throughout the range of motion (ROM) in the navigation system. In each ROM (30, 45, 60, 90, max degrees), the data were analyzed with a ANOVA test, and mean values were compared by the multiple comparison test (Turkey HSD test) (p< 0.05). Results. Joint gap assessment revealed significant enlargement in both of extension and 90 degrees in flexion after PCL resection compared with before resection. In kinematic analyses in navigation system, regarding to amount of sagittal movement of tibia, there were significances between before and after PCL resection in 60 and 90 degrees in flexion, 1.2mm difference in 60 degrees, and 2.3mm difference in 90 degrees in flexion. There were no significance between before and after PCL resection in the other degrees in flexion. Regarding to the other analyses, varus/ valgus and rotation, there were no differences between before and after resection of PCL. In addition, concerning ROM, maximum extension angle is significantly lower, and maximum flexion angle is significantly higher after than before PCL resection. Discussion. These results demonstrated that CS polyethylene insert might have a stability of femoro-tibial joint nearly after PCL resection as well as before PCL resection. The main design feature of Triathlon CS insert is single radius and rotary arc, in addition, the posterior lip is same as that of Triathlon CR, which can be the factor to avoid paradoxical anterior movement and to permit internal and external rotation between femoral and tibial component. Due to the design features and benefits, there is a high possibility that use of CS insert without PCL can lead same stability as PCL remained, and improvement of ROM. Based on these backgrounds, it is suggested that CS insert may have an additional choice of PCL resection in case of tight gap of flexion in TKA

Purpose. To establish the reliability of reporting and recording revision hip and knee arthroplasties by comparing data in the National Joint Registry (NJR), Hospital Episode Statistics (HES) and our local theatre records. Methods. The paper theatre registers for all orthopaedic theatres in the Royal Derby Hospitals NHS Trust were examined for details of revision hip and knee replacements carried out in 2007 and 2008. This was then cross-checked and merged with the local electronic theatre data to obtain a definitive local record of all revision hip and knee arthroplasties. Data for the same period was requested from the NJR and HES and these data were checked against our definitive local record for discrepancies. The HES codes used were the same codes used to compile the recent NJR annual reports. Results. The theatre registers and ORMIS identified 271 revision hip and knee arthroplasties in the study period. The NJR had corresponding data for 176 (65%) of these, and HES had 250 (92%). 10 cases (4%) were not recorded by either NJR or HES: 8 secondary resurfacings of patellae and 2 posterior lip augmentations in hips. Of those operations “missed” by HES, most had been assigned a correct “W” code, but had a “Y” or “Z” OPCS code not used in the NJR annual reports. Conclusion. When HES and the NJR data are combined, they are an accurate representation of real practice. More robust methods of reporting revision arthroplasty to the NJR are required. The OPCS codes used to indicate a revision need to be reviewed

Tunning fork lines (TFL) were drawn on ankle anterior-posterior radiograph to assess the talar shift. A 3-D ankle joint reconstruction was prepared by mapping normal ankle joint using auto CAD in 1997. Tunning fork lines were drawn using normal anatomical landmarks on saggital, coronal and transverse planes. The ankle joint anatomical relationship with talus was studied in various rotation simulating radiographic anterior-posterior views and talar shift was studied. Between 2006 and 2012 on antero-posterior view of ankle radiographs and PACS, ‘Tunning Fork Lines’ (TFL) were drawn. The superior two vertical lines of the TFL were drawn above the ankle joint perpendicular to the distal tibial articular surface. First line tangent to anterior lip of the inferior tibio-fibular joint and second line tangent to the posterior lip of the inferior tibio-fibular joint parallel to each other. The horizontal third line was drawn parallel to distal tibial articular surface perpendicular to first two lines connecting them. The fourth line (handle of the tunning fork) was drawn vertically below the ankle joint midway between the first two lines perpendicular to the third line. In a normal radiograph the superior-lateral dome of the talus lies medial to the handle of TFL, and in ankle with talar shift the dome of the talus crosses this line laterally. In two district hospitals 100 radiographs were observed by 4 observers in 67 males and 33 females with mean age of 49 (15–82) years. The TFL confirmed talar shift with sensitivity of 99.2 % showing talarshift and inferior tibio-fibular ankle diastasis. We conclude that in ankle anterio-posterior view it is possible to comment on the talar shift and diastasis of the ankle joint if proper ankle mortise view is not available

Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femolo-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femolo-tibial joint with use of CS polyethylene insert before and after PCL resction using computer assisted navigation system intra-operatively in TKA. Materials and Methods. Twenty-four consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. In all patients, difference between extension and flexion gap was under 3mm after bony cut of femur and tibia. During surgery, CS polyethylene tibial trial insert were inserted after trial implantation of femoral and tibial components, before and after resection of PCL, respectively. The kinematic parameters of the soft-tissue balance, and amount of coronal (valgus/varus), sagittal (anterior/posterior) and rotational relative movement between femur and tibia were obtained by interpreting kinematics, which display tables throughout the range of motion (ROM) (Figure1). During record of kinematics, the surgeon gently lifted the experimental thigh three times, flexing the hip and knee. In each ROM (30, 45, 60, 90, max degrees), the data were analyzed with paired t-test, and an ANOVA test, and mean values were compared by the multiple comparison test (Turkey HSD test) (p < 0.05). Results. In coronal (valgus/varus) movement, there are no difference between before and after resection of PCL in all ROM. Regarding to amount of sagittal movement of tibia, tibia was slightly shifted approximately 0.75mm posteriorly in 60 degrees of flexion (p=0.013). There are no significance between before and after PCL resection in the other ROM. In addition, concerning ROM, maximum extension angle is significantly lower, and maximum flexion angle is significantly higher after than before PCL resection. Discussion. These results demonstrated that CS polyethylene insert might have a stability of femoro-tibial joint nearly after PCL resection as well as before PCL resection. The main design feature of Triathlon CS insert is single radius and rotary arc, in addition, the posterior lip is same as that of Triathlon CR, which can be the factor to avoid paradoxical anterior movement and to permit internal and external rotation between femoral and tibial component. This study was localized at point of certain situation that difference between extension and flexion gap is under 3mm after bony cut of femur and tibia during surgery. Due to the design features and benefits, there is a high possibility that use of CS insert without PCL can lead same stability as PCL remained, and improvement of ROM. Based on these backgrounds, it is suggested that CS insert may have an additional choice of PCL resection in case of tight gap of flexion in TKA

The goals of total knee arthroplasty (TKA) are to relieve pain, restore function, and provide a stable joint. In regard to types of implants, the workhorses are posterior cruciate retaining (CR), posterior stabilised (PS), and posterior stabilised constrained (PSC) designs. However, the continuum of constraint now ranges from standard cruciate retaining (CR-S) to CR lipped (CR-L), to anterior stabilised (CR-AS), to posterior stabilised, to a PS “plus” that fits with a PS femoral component but provides a small degree of varus-valgus constraint, to a PSC or constrained condylar type of device, to a rotating hinge. As the degree of deformity, bone loss, contracture, ligamentous instability and osteopenia increases, so does the demand for prosthetic constraint. When deformity is minimal and the posterior cruciate ligament (PCL) is intact and functional, a CR-S device is appropriate. For moderate deformity with deficiency or compromise of the PCL, a CR-AS or posterior stabilised device is warranted. In severe cases, with attenuation or absence of either of the collateral ligaments, a constrained condylar device, with options of stems, wedges and augments, is advisable. In salvage situations, when both collaterals are compromised, a rotating hinge should be utilised. Prerequisites for use of a CR-S device are an intact PCL, balanced medial and lateral collateral ligaments, and equal flexion and extension gaps. With a CR-L bearing, a slight posterior lip is incorporated into the sagittal profile of the component to provide a small amount of extra stability in the articulation. It is important for the surgeon to be aware of the design features of the implant system he or she is using. For example, in a system where the CR-S bearing has 3 degrees of posterior slope and the CR-L bearing has no slope, the thickness of a CR-L bearing posteriorly is approximately 2mm greater than the CR-S. A CR-L bearing is indicated for to provide stability where the flexion gap is just slightly looser than the extension gap and the PCL is intact. If the patient's knee is somewhat lax in flexion and stable in extension, a CR-L bearing may help to stabilise both the flexion and extension gaps yet still allow the knee to obtain full extension, whereas if a CR-S bearing in the next thicker size is used to stabilise the flexion gap, a flexion contracture may result. CR-AS bearings are indicated when the flexion and extension gaps are balanced, but the PCL is deficient, and the surgeon does not want to change to a PS design, which requires additional bony resection of intercondylar notch. The PCL is one of the strongest ligaments in the knee, and affords inherent stability to the TKA. In flexion, the PCL not only affords AP stability, but also imparts flexion gap stability, acting as a lateral stabiliser of the medial compartment and a medial stabiliser of the lateral compartment. The PCL has a crucial role with respect to femoral rollback, which imparts added efficiency to the extensor mechanism. PCL retention is a more biologically preserving operative intervention than PS-TKA