Posterior Joint Line Research Articles

Utility of Dynamic Sonographic Evaluation of Left Knee Pain & Locking in a Softball Catcher

HISTORY: An 18 year-old softball catcher presenting with a 3 year history of left progressive postero-lateral knee discomfort with associated knee locking when squatting or deep knee flexion. Onset was 3 years ago when she was in a squat position during a softball game. She had been avoiding aggravating activities and initially sought medical care 3 months ago, presenting to an orthopedic specialist’s clinic. Following a negative MRI, she was referred to our clinic for diagnostic ultrasound of the knee. She reported no reliable way to reproduce locking, but, when locking does occur, she must manually unlock herself. Previous treatment included 8 weeks of physical therapy without benefit. PHYSICAL EXAMINATION: No discoloration or swelling of the left knee. Non-antalgic gait. Valgus alignment with dynamic valgus on single leg squat. Posterior lateral joint line tenderness. No other focal tenderness. Full and symmetric bilateral knee active range of motion without pain, except in terminal flexion. Negative McMurray’s, cruciate and collateral ligament testing and dial test. 9/9 Beighton criteria. DIFFERENTIAL DIAGNOSIS: 1. Meniscocapsular separation 2. Lateral meniscus injury 3. Proximal tibiofibular ligament injury 4. Popliteus muscle/tendon injury 5. Anteriolateral complex sprain 6. PFL injury TEST AND RESULTS: MRI: Subtle irregularity of posterior superior meniscocapsular fascicle deemed secondary to volume-averaging artifact. Otherwise, no discrete pathology was noted. Ultrasound: No discrete lesion of entirety of lateral meniscus on static exam. Development of a separation (3.1mm) between posterior knee capsular tissue and posterior outermost fiber of left lateral meniscus when knee is in near full flexion. FINAL WORKING DIAGNOSIS: left postero-lateral meniscocapsular separation TREATMENT AND OUTCOMES: Management options (expectant management, injection options to mitigate pain, and a surgery) were discussed. Patient elected surgical fixation of lateral meniscus. Arthroscopic fixation of lateral meniscus with 2 vertical mattress sutures using a FasTFix device was performed. After 4 weeks of bracing to allow proper surgical healing, she was able to start using an elliptical at 6 weeks and jogging at 9 weeks. She remains void of pre-surgical pain and locking at 16 weeks post-operatively.

Fluoroscopy-Guided Sacroiliac Intraarticular Injection via the Middle Portion of the Joint.

Sacroiliac intraarticular injection is necessary to confirm sacroiliac joint (SIJ) pain and is usually performed via the caudal one-third portion of the joint. However, this is occasionally impossible for anatomical reasons, and the success rate is low in clinical settings. We describe a technique via the middle portion of the joint. Observational study. Enrolled were 69 consecutive patients (27 men and 42 women, with an average age of 53 years) in whom the middle portion of 100 joints was targeted. With the patient lying prone-oblique with the painful side down, a spinal needle was inserted into the middle portion of the joint. Subsequently, the fluoroscopy tube was angled at a caudal tilt of 25-30° to clearly detect the recess between the ilium and sacrum and the needle depth and direction. When the needle reached the posterior joint line, 2% lidocaine was injected after the contrast medium outlined the joint. The success rate of the injection method was 80% (80/100). Among 80 successful cases, four were previously unsuccessful when the conventional method was used. Intraarticular injection using the new technique was unsuccessful in 20 joints; in three of these cases, the conventional method proved successful, and no techniques were successful in the other 17 cases. The injection technique via the middle portion of the joint can overcome some of the difficulties of the conventional injection method and can improve the chances of successful intraarticular injection.

Fluoroscopic Sacroiliac Joint Injection: Is Oblique Angulation Really Necessary?

Background: The conventional technique for sacroiliac (SI) joint injection involves aligning the anterior and posterior aspects of the SI joint under fluoroscopic guidance and then entering the SI joint in the most caudal aspect. Objective: We wish to highlight that there is no added advantage to aligning both the anterior and posterior joint lines of the SI joint as it is time consuming, associated with additional radiation exposure, and may make the entry into the posterior SI joint technically more difficult. Study Design: Observational study. Setting: Pain Clinic, Department of Anesthesiology. Methods: With the patient lying prone on fluoroscopy table, SI joint injection is performed with a 22 G, 10 cm spinal needle in a true anteroposterior (AP) view, where anterior and posterior SI joint spaces are seen as separate entities, where the medial joint space represents the posterior SI joint and the lateral joint space represents the anterior SI joint. The distal 1 cm of the medial joint space is entered under AP view. If the SI joint is seen as a straight line rather than 2 joint spaces in the AP view then the image intensifier of the fluoroscope was tilted cranially to elongate the image of the lower part of the posterior SI joint, thus facilitating entry into this part of the joint which was confirmed by administering 0.3 to 0.5 mL of radiopaque contrast medium. Result: Sixty SI joints of 58 patients were injected under an AP fluoroscopic view. Forty-two (70%) SI joints were seen as 2 separate medial and lateral joint spaces and were entered in distal 1 cm of the medial joint space. In 18 (30%) joints seen as a straight line rather than 2 separate spaces, the image intensifier of the fluoroscope was tilted cranially to elongate the image of the lower part of the posterior SI joint and then the SI joint was entered in its distal 1 cm. Confirmation of entry into the SI joint was confirmed by with 0.3 to 0.5 mL of radiopaque contrast medium. In 4 cases the joints did not show the correct radiopaque contrast spread (3/42 and 1/18) although the needle seemed to be in the joint space. Limitations: Small sample size. Conclusion: Aligning the anterior and posterior aspects of SI joint for fluoroscopic guided SI joint injection is not necessary for the success of the block. Key words: Sacroiliac joint, injection, anteroposterior view, oblique angulation, fluoroscopic technique

Correlation between the distal anterior femoral cortical axis and femoral rotational alignment: an anatomic study.

To determine the correlation between the distal anterior femoral cortical axis (DAFCA) and the femoral rotational alignment/axis. Magnetic resonance images (MRI) of 82 knees in 34 men and 23 women aged 16 to 47 (mean, 33.4) years were reviewed by a musculoskeletal radiologist. Their diagnoses included meniscal tear (n=4), chondromalacia (n=25), anterior cruciate ligament tears (n=11), and normal (n=42). In all patients the collateral ligaments were intact. The transepicondylar axis (TEA), posterior condylar axis (PCA), Whiteside line (WL), and joint line were drawn on the images, and the condylar twist angle (CTA), TEA-WL angle, DAFCA, epicondylar cortical angle (ECA), and condylar cortical angle (CCA) were measured. The correlations among ECA, CCA, and CTA (control) were assessed. The mean distances between the joint line and the TEA, PCA, and DAFCA were 30.8, 22.1, and 62.2 mm, respectively. The angles subtended by the intersection between the standard axes (TEA, PCA, and WL) and the DAFCA were determined. There was correlation between the CTA and ECA (r=0.34, p<0.05), between the ECA and the CCA (r=0.80, p<0.0001), and between the CTA and the CCA (r=- 0.19, p=0.08). There was correlation between the DAFCA and TEA and PCA; DAFCA can be used to determine the femoral rotational alignment when the standard landmarks are distorted by severe soft tissue and bone loss.

Posterior Cruciate Ligament Retention versus Posterior Stabilization for Total Knee Arthroplasty: A Meta-Analysis.

IntroductionAlthough being debated for many years, the superiority of posterior cruciate-retaining (CR) total knee arthroplasty (TKA) and posterior-stabilized (PS) TKA remains controversial. We compare the knee scores, post-operative knee range of motion (ROM), radiological outcomes about knee kinematic and complications between CR TKA and PS TKA.MethodsLiterature published up to August 2015 was searched in PubMed, Embase and Cochrane databases, and meta-analysis was performed using the software, Review Manager version 5.3.ResultsTotally 14 random control trials (RCTs) on this topic were included for the analysis, which showed that PS and CR TKA had no significant difference in Knee Society knee Score (KSS), pain score (KSPS), Hospital for Special Surgery score (HSS), kinematic characteristics including postoperative component alignment, tibial posterior slope and joint line, and complication rate. However, PS TKA is superior to CR TKA regarding post-operative knee range of motion (ROM) [Random Effect model (RE), Mean Difference (MD) = -7.07, 95% Confidential Interval (CI) -10.50 to -3.65, p<0.0001], improvement of ROM (Fixed Effect model (FE), MD = -5.66, 95% CI -10.79 to -0.53, p = 0.03) and femoral-tibial angle [FE, MD = 0.85, 95% CI 0.46 to 1.25, p<0.0001].ConclusionsThere are no clinically relevant differences between CR and PS TKA in terms of clinical, functional, radiological outcome, and complications, while PS TKA is superior to CR TKA in respects of ROM, while whether this superiority matters or not in clinical practice still needs further investigation and longer follow-up.

Stepwise surgical correction of instability in flexion after total knee replacement.

Instability in flexion after total knee replacement (TKR) typically occurs as a result of mismatched flexion and extension gaps. The goals of this study were to identify factors leading to instability in flexion, the degree of correction, determined radiologically, required at revision surgery, and the subsequent clinical outcomes. Between 2000 and 2010, 60 TKRs in 60 patients underwent revision for instability in flexion associated with well-fixed components. There were 33 women (55%) and 27 men (45%); their mean age was 65 years (43 to 82). Radiological measurements and the Knee Society score (KSS) were used to assess outcome after revision surgery. The mean follow-up was 3.6 years (2 to 9.8). Decreased condylar offset (p < 0.001), distalisation of the joint line (p < 0.001) and increased posterior tibial slope (p < 0.001) contributed to instability in flexion and required correction at revision to regain stability. The combined mean correction of posterior condylar offset and joint line resection was 9.5 mm, and a mean of 5° of posterior tibial slope was removed. At the most recent follow-up, there was a significant improvement in the mean KSS for the knee and function (both p < 0.001), no patient reported instability and no patient underwent further surgery for instability. The following step-wise approach is recommended: reduction of tibial slope, correction of malalignment, and improvement of condylar offset. Additional joint line elevation is needed if the above steps do not equalise the flexion and extension gaps.

Correlation Between Asymmetric Resection of Posterior Femoral Condyles and Femoral Component Rotation in Total Knee Arthroplasty

Objectives:Pertaining to peculiar designs of current knee prostheses, more bone is removed from posteromedial femoral condyle than posterolateral condyle to obtain desired femoral component rotation. The aim of our study was to evaluate whether there is a correlation between the asymmetry of the cuts and the femoral component rotation in total knee arthroplasty.Methods:We built a model to simulate anterior chamfer cut (ACC) performed during total knee arthroplasty for measuring posterior condylar offset (PCO). Right knee axial MRI slices of a total 290 consecutive patients (142 male, 138 female, and mean age 31.39 ± 6.6) were examined. A parallel line to surgical transepiphyseal axis was drawn, and placed at the deepest part of trochlear groove. Posteromedial and posterolateral condylar offsets were measured by drawing perpendicular lines to ACC beginning from the intersection points of both anteromedial and anterolateral cortices to posterior joint line (PJL), respectively. Differences between posteromedial and posterolateral PCO were calculated, and femoral rotation angles (FRA) relative to PJL were measured.Results:The mean surgical FRA was 4.76 ± 1.16 degrees and the mean PCO differencesss- was 4.35 ± 1.04 mm for the whole group and there was no statistically significant difference between genders. There was a strong correlation between surgical FRA and PCO difference (p<0.0001, r=0.803). Linear regression analyses revealed that 0.8 mm of difference between the anteroposterior dimensions of medial and lateral PCO corresponds to 1 degree of surgical FRA (p<0.0001, R2=0.645).Conclusion:Correlation between the asymmetry of posterior chamfer cuts and achieved femoral component rotation can verify the accuracy of desired rotation, intraoperatively. However, further clinical investigations should be planned to test the results of our morphometric study.

Significance of asymmetrical posteromedial and posterolateral femoral condylar chamfer cuts in total knee arthroplasty.

Orthopedic surgeons remove more bone from the posteromedial femoral condyle than the posterolateral condyle to achieve the desired femoral component rotation. Here, the correlation between the asymmetry of chamfer cuts and femoral component rotation in total knee arthroplasty was determined. A model was built to simulate anterior chamfer cuts performed during total knee arthroplasty to measure posterior condylar offset. Right knee axial magnetic resonance imaging slices were examined from 280 consecutive patients (142 men, 138 women; mean age 31.4±6.6years). The anatomic and surgical transepicondylar axes, as well as the posterior condylar joint line, were drawn. Differences in the posteromedial and posterolateral offsets and the femoral rotation angles relative to the posterior joint line were measured. The mean surgical femoral rotation angle was 4.8°±1.2°, and the mean posterior condylar offset difference was 4.4±1mm, with a strong correlation (p<0.0001; r=0.803). There was no statistically significant difference between genders. Linear regression analyses revealed that a 0.8-mm difference between the anteroposterior dimensions of the medial and lateral posterior condylar offsets corresponded to 1° of femoral external rotation (p<0.0001, R (2)=0.645). The accuracy of the applied technique intra-operatively can be verified by correlating the asymmetry of posterior chamfer cuts with the achieved femoral component rotation, as determined by measuring the thicknesses of posterior chamfer cuts with a caliper. Technical errors can also be minimized by confirming the association between the femoral component rotation-as predicted by the posterior condylar offset difference-and the preoperatively measured femoral rotation angle. II.

Relationship of the posterior femoral axis of the "kinematically aligned" total knee arthroplasty to the posterior condylar, transepicondylar, and anteroposterior femoral axes.

A recent proposed modification in surgical technique in total knee arthroplasty (TKA) has been the introduction of the "kinematically aligned" TKA, in which the angle and level of the posterior joint line of the femoral component and joint line of the tibial component are aligned to those of the "normal," pre-arthritic knee. The purpose of this study was to establish the relationship of the posterior femoral axis of the "kinematically aligned" total knee arthroplasty (TKA) to the traditional axes used to set femoral component rotation. One hundred and fourteen consecutive, unselected patients with preoperative MRI images undergoing TKA were retrospectively reviewed. The transepicondylar axis (TEA), posterior condylar axis (PCA), antero-posterior axis (APA) of the trochlear groove, and posterior femoral axis of the kinematically aligned TKA (KAA) were templated on axial MRI images by two independent observers. The relationships between the KAA, TEA, APA, and PCA were determined, with a negative value indicating relative internal rotation of the axis. On average, the KAA was 0.5° externally rotated relative to the PCA (minimum of -3.6°, maximum of 5.8°), -4.0° internally rotated relative to the TEA (minimum of -10.5°, maximum of 2.3°), and -96.4° internally rotated relative to the APA (minimum of -104.5°, maximum of -88.5°). Each of these relationships exhibited a wide range of potential values. Using a kinematically aligned surgical technique internally rotates the posterior femoral axis relative to the transepicondylar axis, which significantly differs from current alignment instrument targets.

How Frequently Do Four Methods for Mechanically Aligning a Total Knee Arthroplasty Cause Collateral Ligament Imbalance and Change Alignment from Normal in White Patients? AAOS Exhibit Selection.

Mechanically aligned total knee arthroplasty can create a tight collateral ligament in 0° of extension, instability in a compartment between 0° of extension and 90° of flexion that is uncorrectable by collateral ligament release, and changes in limb and knee alignment from normal. The goal of the present study was to calculate the frequency and range of these undesirable consequences. Four methods of mechanically aligned total knee arthroplasty were simulated on fifty normal three-dimensional bone models of the lower extremity from white subjects. Each method resected the distal aspect of the femur and proximal aspect of the tibia perpendicular to their respective mechanical axes. Setting the posterior joint line perpendicular to the anteroposterior axis of the trochlear groove (Method 1), parallel to the transepicondylar axis (Method 2), externally rotated 3° with respect to the posterior condylar axis (Method 3), and parallel to the tibial resection in 90° of flexion with the use of gap-balancing (Method 4) aligned internal-external rotation of the femoral component. The proportion of total knee arthroplasties requiring a ≥2-mm release of a tight collateral ligament was 34% for the medial collateral ligament and 30% for the lateral collateral ligament. The proportion of total knee arthroplasties with ≥2 mm of instability between 0° of extension and 90° of flexion was 56% in the medial compartment and 6% in the lateral compartment for Method 1, 74% and 6% for Method 2, and 42% and 0% for Method 3. Method 4 did not cause ligamentous instability. The proportion of arthroplasties with a ≥2° change from normal was 58% for limb alignment and 58% for knee alignment. Surgeons should be aware that, when using the four methods of mechanically aligning a total knee arthroplasty, they will frequently have to manage a wide range of collateral ligament imbalances that are complex, cumulative, and uncorrectable by collateral ligament release, and a wide range of changes in limb and knee alignment from normal. Patients who perceive these changes in stability, limb alignment, and knee alignment may be dissatisfied and require counseling.

Femoral bone and cartilage wear is predictable at 0° and 90° in the osteoarthritic knee treated with total knee arthroplasty.

Kinematically aligned total knee arthroplasty (TKA) positions the femoral component at the natural angle and level of the distal (0°) and posterior (90°) joint line. This technique applies referencing guides at 0° and 90° that are adjusted to compensate for wear and kerf and perform resections equal in thickness to the femoral component. Knowing whether femoral bone and cartilage wear is predictable would assist in establishing general guidelines for adjusting the resection level of these two referencing guides. This study tests the hypothesis that femoral bone and cartilage wear is predictable at 0° and 90° in the varus and valgus osteoarthritic knee treated with TKA. The study consists of 205 patients and 208 knees with Kellgren-Lawrence Grade 3 or 4 osteoarthritis and treated with a TKA. Each knee had a narrow slice (2 mm) preoperative 1.5 tesla magnetic resonance image in the sagittal plane. Femoral bone and cartilage wear at 0° and 90° was computed from best-fit circles superimposed on the peripheral boundary of the subchondral bone on the medial and lateral femoral condyles. Overall, 99.5% of knees had minimal bone wear (<1 mm) at 0° and 90°. In the 74% (154 of 208) of knees with a varus deformity, 92% at 0° and 2 % at 90° had >1 mm cartilage wear on the medial femoral condyle. In the 26% (54 of 208) of knees with a valgus deformity, 78% at 0° and 55% at 90° had ≥1 mm cartilage wear on the lateral femoral condyle. As a general guideline, adjustment for femoral bone wear is rarely required when performing kinematically aligned TKA. Most osteoarthritic knees require adjustment of the distal referencing guide to compensate for cartilage wear on the medial femoral condyle in the varus knee and the lateral femoral condyle in the valgus knee. Adjustment of the posterior referencing guide is required in about half of valgus osteoarthritic knees to compensate for lateral cartilage wear at 90°. Knowing that bone wear is rare and cartilage wear is predictable in varus and valgus Kellgren-Lawrence Grade 3 or 4 osteoarthritic knees helps establish general guidelines for adjusting the distal and posterior femoral referencing guides to restore the natural angle and level of the femoral joint lines when performing kinematically aligned TKA with generic instruments. IV.

Posterior shoulder instability secondary to reverse humeral avulsion of the glenohumeral ligament

Posterior shoulder instability resulting from a disruption of the posterior capsular structures has been reported. We present the largest series of these injuries in the published literature, propose a definition and highlight the clinical presentation, radiological findings, and associated injuries. A retrospective review of a single shoulder surgeons database was performed identifying posterior instability cases associated with disruption of the posterior capsule. Chart, radiological imaging, and intra-operative findings were reviewed. Nineteen patients were identified with an average age lower than the overall posterior instability group. All occurred via a traumatic mechanism, the most common being a forced cross-body adduction. The only consistent symptom was posterior joint line pain. MRI reporting was found to be only 50% sensitive, increased to 78.6% when reviewed by the treating surgeon. Associated injuries are common with 58% having a labral tear, 32% a SLAP lesion, 26% a reverse Bankart lesion, 21% a chondral injury, 21% rotator cuff injury, and 11% extension of the tear into the posterior band of the inferior glenohumeral ligament. Disruption of the posterior capsule is a rare cause of recurrent posterior instability. There are no specific symptoms that identify the injury, though a mechanism of forced cross-body adduction should raise suspicion. Identification of the injury requires specific attention to the posterior capsule on MRI, preferably performed with the arm in slight external rotation and routine visualization of the posterior capsule via viewing from the anterior portal.

Quantitative 3-Dimensional Analysis of Preoperative and Postoperative Joint Lines in Total Knee Arthroplasty: A New Concept for Evaluation of Component Alignment

We developed a quantitative 3-dimensional (3D) technique for the assessment of changes in the tibial joint line as well as distal and posterior femoral joint lines using a 3D image-matching procedure. In this study, we performed 3D joint line assessment of 20 knees that had undergone total knee arthroplasty. Most of the knees exhibited proximal change in the tibial joint line, distal change in the distal femoral joint line, and anterior change in the posterior femoral joint line. There were clear differences in changes in the joint lines between the medial and lateral condyles. The findings indicate that changes in the joint line should be individually assessed for each condyle and that the assessment should include not only the tibial condyle but also the distal and posterior femoral condyles.

Shoulder Pain Professional Baseball Pitcher

HISTORY A 28 year old professional baseball pitcher was promoted to the major league club after Spring training and pitched successfully with no pain until the end of April when he began to have insidious onset of pain in his throwing shoulder. The pain was posteriorly and gradually worsened. Evaluation by the trainer suggested an infraspinatus or teres minor strain and he was treated with stretching, modalities and ibuprofen. Despite treatment his pain worsened so that he was sore for hours after pitching. He was evaluated by the team physician and radiographs were normal. After 3 weeks of continued treatment he could no longer throw due to the pain. EXAMINATION Upon initial evaluation he had no atrophy or deformity with no winging, but when viewed from behind he was noted to have scapular dyskinesia. He had full ROM of his shoulders with no suggestion of GIRD. He was entirely neurologically intact for sensation, motor and reflexes. He had pain with resisted external rotation with his arm at the side, but he had no weakness. He had a negative apprehension sign, relocation sign, lift off test, Whipple test, Speed's test and Spurling maneuver. He had tenderness on the lateral border of his scapula but not over his posterior joint line. DIFFERENTIAL DIAGNOSIS Labrum tear “Occult” instability Strain teres minor or infraspinatus Stress fracture TESTS AND RESULTS Plain radiographs normal MRI of scapula: edema lateral border CT scan of scapula: stress fracture lateral scapula Evaluation by orthopaedic oncologist who ruled out tumor WORKING DIAGNOSIS Stress fracture of scapula TREATMENT Rest from throwing for 4 to 6 weeks Gradual return to throwing after 2 months Developed elbow pain and shut down for remainder of season Repeat MRI and CT scan show resolution of the fracture

Posterior Shoulder Instability in a Competitive Golfer

0943 HISTORY: A 17 year old male who played golf competitively for his high school team was hitting a ball off the tee when he injured his left, non-dominant shoulder. When in his backswing he felt pain, but in the follow through he felt a pop. The pop was accompanied by severe pain and he was unable to continue to play golf. He was seen by his primary care physician who examined him and performed and MRI of the shoulder. The patient consulted with us three weeks after his injury. At that time, he complained of primarily posterior shoulder pain which was non-radiating. He did not have any parasthesias, weakness or any sense that his shoulder was unstable. He did not have a history of any previous injury to his shoulder. He had no history of connective tissue disorders or of any systemic illnesses. PHYSICAL EXAMINATION: The patient had no atrophy or winging of the scapula. He had full elevation of his shoulder with pain posteriorly with elevation. He had equal motion compared to the other shoulder for internal and external rotation both with the arm elevated and with the arms at the side. His neurological examination was entirely normal with no weakness or sensory deficits. He had a negative anterior apprehension test, posterior apprehension test and a grade II sulcus sign bilaterally. He had negative impingment signs and a negative active compression test. He could not relax for laxity testing on the involved shoulder. He was tender only along his posterior joint line. DIFFERENTIAL DIAGNOSIS: Strain posterior shoulder muscle Tear rotator cuff Labrum tear Posterior instability TEST AND RESULTS: Plain radiographs: Anterior-posterior and axillary radiographs: normal MRI with gadolinium: tear of the posterior labrum FINAL WORKING DIAGNOSIS: Posterior instability of the shoulder TREATMENT AND OUTCOMES: Non-operative Strengthening program initiated within six weeks post injury showed no improvement in shoulder function or alleviation of symptoms after 6 months Diagnostic arthroscopy: reverse Bankart lesion Arthrotomy with repair reverse Bankart and capsular shift Placed in a brace post operatively Initiated and completed a structured rehabilitation program Returned to sports 6 months postoperatively with no limitations

Use of prepolymerized cement spacers to augment the femoral component in revision total knee arthroplasty: A clinical outcome report and laboratory experiment

A technique for revision total knee arthroplasty managing posterior femoral condylar bone loss with prepolymerized polymethyl methacrylate cement spacers as augments to the femoral component is described in 10 consecutive cases. The maximum follow-up time is 63 months. This method allows for maintenance of the posterior joint line, which in turn facilitates appropriate flexion-extension gap balancing. The cement spacers are inexpensive compared with metal augments. An experimental study confirms that the cement spacers produce a chemical and physical bond with fresh cement. This eliminates the risk of particulate debris production between the cement augment and the fixation cement. Although the cement spacers have been produced to match one manufacturer’s implants, they could be applied to other knee systems.

Bone loss in revision total knee arthroplasty: Graft options and adjuncts

The treatment of small bone defects in revision total knee arthroplasty should make immediate full weight bearing and full therapy possible, provide long-term stability for the implants, and restore bone stock. These objectives are achieved with bone grafts if the defects are cavitary or small (involving less than one fourth of the cortical rim) segmental defects. These objectives are achieved with porous metal augments if the defects are segmental and involve more than one fourth of the cortical rim. The treatment of bone loss on the femur must allow the re-establishment of the distal and posterior joint lines as well as provide a firm fixation base for the implants. © 2003 Elsevier Inc. All rights reserved.

Injury to the popliteal artery and its anatomic location in total knee arthroplasty

Injury to the popliteal artery during total knee arthroplasty (TKA) is a devastating complication. Although infrequent, these injuries can result in the need for further surgery, including revascularization or possibly even amputation. Several mechanisms are capable of producing direct trauma to the popliteal artery, including the use of posterior retractors. We investigated the proximity of the popliteal artery to the tibial joint surface during TKA to identify crucial steps in the procedure at which the artery was at highest risk for injury. TKA was performed on cadaveric specimens, and serial intraoperative arteriograms were taken throughout the procedure, demonstrating the potential for arterial injury by the instrumentation. Additionally, 50 transverse magnetic resonance imaging scans of unrelated knees were analyzed for the position of the popliteal artery relative to the midline of the tibial plateau as well as at a level 5 to 10 mm below this, at the site of a typical resection during TKA. All of the arteriograms showed the artery to be a lateral structure at the joint line. Additionally a posterior retractor placed the artery at risk when it was placed in a position lateral to the posterior cruciate ligament or when it was injudiciously inserted more than 1 cm into the soft tissues. Hyperextension of the knee, which might occur during preparation of the patella, produced dramatic tenting of the artery over the posterior joint line. These results demonstrate that the popliteal artery is at significant risk during TKA, particularly if posterior retractors are placed in a position lateral to the midline of the joint. Both hyperflexion and especially hyperextension produced severe deformities and kinking of the artery and would particularly jeopardize an artery with atherosclerosis. Our findings suggest that the popliteal artery may be at least risk during TKA if posterior retractors are placed medial to the midline of the tibial plateau and if care is taken to avoid extremes of both flexion and extension.

Managing bone loss with augmentation.

Augmentation blocks are effective ways of treating the problem of bone loss on the distal and posterior femur. They allow accurate and durable reestablishment of the distal and posterior joint line in revision total knee replacements. They are particularly appropriate in revisions being carried out in elderly, osteopenic patients with severe deformities or instabilities. Revision instrumentation can and should philosophically and mechanically remind one of and be consistent with primary total knee instrumentation.

KNEE PAIN - MENISCUS TEAR 829

HISTORY - A 23-year-old senior male basketball player for a Division I university landed after an attempted blocked shot and felt intense pain over the posterior-lateral aspect of his knee. He did not feel a pop or have complaints of instability. He had no previous history of knee pain or injury. The fifth year senior wanted to complete his final season if possible. PHYSICAL EXAM - The athlete was evaluated at courtside by the athletic trainer and in the training room by the team physician. His primary complaint was of pain and inability to fully extend his knee. Range of motion was 15°-60° limited by pain. No gross effusion was present. He was focally tender over the posterior lateral joint line. Ligamentous stability appeared to be intact with a negative Lachman's, negative posterior sag, negative external rotation recurvatum, and negative laxity to varus and valgus stress at 0° and 30°. McMurray's examination instituted pain laterally but was not complete secondary to limited range of motion. DIFFERENTIAL DIAGNOSIS: Lateral meniscus tear, 2. Posterior-lateral complex injury, 3. Popliteal tendon rupture, 4. Lateral collateral ligament strain, 5. Fracture or bone bruise. TEST AND RESULTS: Plain radiographs were negative for fracture or bony pathology. Magnetic resonance imaging revealed a peripheral tear of the entire posterior horn of the lateral meniscus and Grade I changes in the lateral collateral ligament and posterior lateral complex. FINAL DIAGNOSIS: After review of the test results with the athlete, his family, and his athletic trainer, he was taken to surgery for arthroscopy of his knee. A large bucket handle tear of his posterior meniscus was identified locked in the intercondylar notch. The unstable fragment comprised 60-70% of his entire meniscus and 100% of his posterior horn. Meniscal repair was selected over meniscectomy due to the peripheral nature and overwhelming size of the tear. An accelerated aggressive rehabilitation allowing full weight-bearing and full range of motion immediately was instituted. However, he was restricted from twisting and cutting activities for two months. TREATMENT: While meniscus tears are not an uncommon injury in elite athletes, they do present a difficult dilemma in recommendation and treatment options for coaches, athletic trainers, team physicians, and orthopaedic surgeons. This case notes an athlete playing in his final collegiate season who is an important cog in his team's success. The player, coach, athletic trainer, and physician all would like to have the athlete back as soon as possible which would imply partial meniscectomy. Nonetheless, due to the likelihood of early degenerative arthritis with a nearly complete meniscectomy, a meniscal repair with its associated longer rehabilitation would best serve this patient in the long run.