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Biomedical subjects

Christopher D Harner

Publications and source records attributed to Christopher D Harner.

36 records · Page 2Linked to original sources
PubMed2004

Surgical management of knee dislocations.

BACKGROUND: The evaluation and management of knee dislocations remain variable and controversial. The purpose of this study was to describe our method of surgical treatment of knee dislocations with use of a standardized protocol and to report the clinical results. METHODS: Forty-seven consecutive patients presented with an occult (reduced) or grossly dislocated knee. Fourteen of these patients were not included in this series because of confounding variables: four had an open knee dislocation, five had vascular injury requiring repair, three were treated with external fixation, and two had associated injury. The remaining thirty-three patients underwent surgical treatment for the knee dislocation with our standard approach. Anatomical repair and/or replacement was performed with fresh-frozen allograft tissue. Thirty-one of the thirty-three patients returned for subjective and objective evaluation with use of four different knee rating scales at a minimum of twenty-four months after the operation. RESULTS: Nineteen of the thirty-one patients were treated acutely (less than three weeks after the injury) and twelve, chronically. The mean Lysholm score was 91 points for the acutely reconstructed knees and 80 points for the chronically reconstructed knees. The Knee Outcome Survey Activities of Daily Living scores averaged 91 points for the acutely reconstructed knees and 84 points for the chronically reconstructed knees. The Knee Outcome Survey Sports Activity scores averaged 89 points for the acutely reconstructed knees and 69 points for the chronically reconstructed knees. According to the Meyers ratings, twenty-three patients had an excellent or good score and eight had a fair or poor score. Sixteen of the nineteen acutely reconstructed knees and seven of the twelve chronically reconstructed knees were given an excellent or a good Meyers score. The average loss of extension was 1 degrees, and the average loss of flexion was 12 degrees. There was no difference in the range of motion between the acutely and chronically treated patients. Four acutely reconstructed knees required manipulation because of loss of flexion. Laxity tests demonstrated consistently improved stability in all patients, with more predictable results in the acutely treated patients. CONCLUSIONS: Surgical treatment of the knee dislocations in our series provided satisfactory subjective and objective outcomes at two to six years postoperatively. The patients who were treated acutely had higher subjective scores and better objective restoration of knee stability than did patients treated three weeks or more after the injury. Nearly all patients were able to perform daily activities with few problems. However, the ability of patients to return to high-demand sports and strenuous manual labor was less predictable.

Adolescent↗
PubMed2003

A biomechanical analysis of two reconstructive approaches to the posterolateral corner of the knee.

The objective of this study was to evaluate the effects of the biceps femoris tenodesis and popliteofibular ligament reconstruction on knee biomechanics. Ten human cadaveric knees were tested in the intact, posterolateral corner (PLC)-deficient, and PLC-reconstructed conditions using a robotic/universal force moment sensor testing system. The knees were subjected to: (1) a 134 N posterior tibial load, and (2) a 10 Nm external tibial torque applied to the tibia at full extension, 30 degrees and 90 degrees of flexion. External tibial rotation of the intact knee ranged from 18.3+/-4.6 degrees at full extension to 27.9+/-4.6 degrees at 30 degrees under the 10 Nm external tibial torque. These values increased after sectioning the PLC by 2.8 degrees -7.5 degrees at 30 degrees and 90 degrees respectively. After the popliteofibular ligament reconstruction, external tibial rotation values were not significantly different from those for the intact knee at any angle tested, while values following the biceps tenodesis were as much as 5.7 degrees greater than the intact knee. Under the 134 N posterior tibial load, there were minimal decreases in posterior tibial translation of up to 0.9 mm with the biceps tenodesis and up to 1.6 mm with the popliteofibular ligament reconstruction compared to the intact knee. The in situ forces in the biceps tenodesis were not significantly different than the intact PLC at full extension or 30 degrees, while the in situ forces in the popliteofibular graft were not significantly different at any flexion angle. Our data suggests that by restoring external tibial rotation the popliteofibular ligament reconstruction more closely reproduces the primary function of the PLC as compared to the biceps tenodesis.

Adult↗
PubMed2003

Arthroscopically assisted meniscal allograft transplantation with and without combined anterior cruciate ligament reconstruction.

The menisci provide a vital role in load transmission across the knee joint as well as contribute to knee stability, particularly in the ACL-deficient knee. Loss of the meniscus, in part or in total, significantly alters joint function and predisposes the articular cartilage to degenerative changes, which has been well documented both clinically and radiographically. This study examined clinical and patient-reported outcomes following meniscal allograft transplantation with and without combined ACL reconstruction in a select group of 31 patients with complaints of pain and/or instability (34 meniscal allografts); 11 underwent isolated meniscal transplantation and 20 meniscal transplantation combined with ACL reconstruction. Bony fixation was performed with bone plugs for medial transplants and using a bone bridge for lateral transplants. All patients completed several knee-specific and general measures of health-related quality of life and underwent a comprehensive physical examination. Flexion weightbearing PA radiographs at latest follow-up were compared to those obtained preoperatively. Mean follow-up was 2.9 years (range 2-5.5 years). The Activities of Daily Living and Sports Activities Scale scores were 86+/-11 and 78+/-16, respectively, and the average Lysholm score was 84+/-14. There were no significant differences in these scores based upon which meniscus (medial or lateral) was transplanted, concurrent ACL reconstruction, or the degree of chondrosis at arthroscopy. SF-36 scores indicated that patients were functioning at a level similar to the age- and sex-matched population. Twenty-two patients stated they were greatly improved, 8 were somewhat improved, 1 was without change. All but one patient reported that knee function and level of activity were normal or nearly normal. The average loss of motion compared to the noninvolved side was 3 degrees for extension and 9 degrees for flexion. All but one patient had a negative or 1+ Lachman's test. The remaining patient had a 2+ Lachman's test. Assessment with the KT-1000 arthrometer revealed a side-to-side difference of 2 mm (range -2 mm to 7 mm). Average hop and vertical jump indices were both 85% of the contralateral extremity. No statistically significant joint space narrowing was observed by radiography over time. Meniscal allograft transplantation with and without combined ACL reconstruction in carefully selected patients with complaints of compartmental joint line pain and/or instability appears able to provide relief of symptoms and restore relatively high levels of function, particularly during activities of daily living.

Adolescent↗
PubMed2003

Revision anterior cruciate ligament reconstruction.

Revision ACL surgery is indicated in patients who present with pathologic anterior laxity on clinical examination that reproduces their symptoms of instability during activities of daily living or athletic activities. The goals of the revision ACL surgery are to stabilize the knee, prevent further injury to the articular cartilage and menisci, and maximize the patient's function. Successful revision ACL surgery requires a thorough preoperative evaluation, including a detailed history, physical examination, and radiographic evaluation. Preoperative planning begins with a determination of the mechanisms of failure for the initial ACL reconstruction. Often a primary, as well as secondary cause, for failure can be identified. The determination of the cause of failure is the first step in a carefully-constructed treatment plan, which includes consideration of skin incisions to be used, method of graft removal, hardware removal, the need for a staged procedure or concomitant surgery, graft material selection, tunnel placement, graft fixation, and postoperative rehabilitation protocol. Despite the most meticulous planning, unanticipated findings may be encountered in the operating room, and the preoperative plan should have enough flexibility to accommodate these developments. Finally, it is crucial to counsel the patient preoperatively to limit his or her expectations regarding their surgical outcome. Given the complexity of revision ACL reconstruction, patient expectations must be adjusted to realistically match the potential for success. With proper planning, attention to detail, and appropriate patient expectations, revision ACL surgery can result in a beneficial and satisfying patient outcome.

Anterior Cruciate Ligament↗
PubMed2003

Arthroscopically assisted retrograde fixation of patellar osteochondritis dissecans using fluoroscopic guidance: a case report and technical note.

Osteochondritis dissecans of the patella is a relatively rare condition. Treatment recommendations vary significantly from nonoperative treatment to surgical intervention. Surgical management varies from excision of the lesion to a variety of methods of stabilization. We present a case of patellar osteochondritis dissecans successfully treated with arthroscopically assisted retrograde fixation using fluoroscopic guidance. This surgical technique, which we describe in detail, avoids articular cartilage penetration and the need for an arthrotomy and allows for compression of the lesion with the hardware oriented perpendicular to the defect. It uses both fluoroscopic and arthroscopic imaging techniques for reduction and fixation.

Adolescent↗
PubMed2003

Femoral-sciatic nerve blocks for complex outpatient knee surgery are associated with less postoperative pain before same-day discharge: a review of 1,200 consecutive cases from the period 1996-1999.

BACKGROUND: Outpatient knee surgery has come to involve increasingly complex procedures. The authors present observational data from a nerve block algorithm designed for the care of outpatients undergoing knee surgery. The aim of this report is to demonstrate differences in pain and unplanned hospital admission associated with surgical complexity and nerve blocks used. METHODS: Day-of-surgery outcomes were studied for 1,200 consecutive outpatients undergoing routine arthroscopy or one of six complex outpatient knee procedures. Nerve blocks were administered on the basis of anticipated pain from open incisions in the femoral and sciatic nerve distributions. Regression analysis was used to determine factors associated with postoperative pain and unplanned hospital admissions, and patients were categorized as having received femoral and sciatic nerve blocks (FSB), femoral nerve block only (FNB), or no nerve blocks. RESULTS: Patients undergoing more complex (vs. less invasive) knee surgery were at greater risk for pain (P </= 0.004), whereas the use of FSB (vs. FNB or no block) was associated with less pain (P < 0.01). When no nerve blocks were used, more complex (vs. less invasive) knee surgery was associated with a 10-fold greater risk of hospital admission (P = 0.001). In the regression analyses, more complex surgery (P < 0.001) was associated with increased risk of admission, and the use of FNB or FSB (vs. no block) was associated with a 2.5-fold reduction in unplanned admissions (P = 0.009). CONCLUSIONS: For complex knee surgery, the use of FSB was associated with less pain; the use of FNB or FSB (vs. no block) was associated with fewer hospital admissions.

Adult↗
PubMed2002

PACU bypass after outpatient knee surgery is associated with fewer unplanned hospital admissions but more phase II nursing interventions.

BACKGROUND: The authors recently proposed a recovery scoring system for outpatients receiving regional anesthesia (RA) or general anesthesia (GA). This scoring system was designed to allow qualifying patients to be directly routed to the phase II (step-down) recovery unit instead of the traditional postanesthesia care unit (PACU). We report PACU bypass rates using these criteria, and the extent to which PACU bypass was associated with (1) required nursing interventions in the step-down recovery unit, and (2) successful same-day discharge. METHODS: Day-of-surgery outcomes were studied for 894 outpatients undergoing outpatient sports medicine surgery on the lower extremity. We determined PACU-bypass rates, nursing interventions in the step-down recovery unit for common symptoms, and unplanned hospital admissions. Using logistic regression, we analyzed step-down nursing interventions based on PACU requirement versus PACU bypass, and anesthesia techniques used (GA vs. not, peripheral nerve blocks vs. not). RESULTS: Eighty-seven percent (778/894) of all patients bypassed PACU. Of PACU-bypass patients, 241/778 (31%) required step-down nursing interventions. Of patients requiring PACU, only 19/116 (16%) required additional interventions in step-down (P < 0.001). PACU-bypass patients were almost three times more likely (odds ratio 2.9,P < 0.001) to require at least one nursing intervention in the step-down unit, when compared with patients requiring PACU. Fewer unplanned admissions were required by patients who bypassed PACU (odds ratio = 0.3,P = 0.007). CONCLUSIONS: For outpatient lower extremity surgery, applying our PACU-bypass criteria led to an 87% PACU bypass rate with no reportable adverse events.

Adult↗
PubMed2002

Posterior cruciate ligament injuries.

There is a relative lack of research and literature investigating injuries to the posterior cruciate ligament (PCL), despite the fact that it is an important knee stabilizer. The PCL is injured less frequently than other knee ligaments, and the mechanism is usually a direct blow to the anterior aspect of a flexed knee. Clinical examination of a PCL-deficient knee may reveal a positive posterior drawer, quadriceps active test, or Godfrey test. Chronic PCL insufficiency may result in patellofemoral and medial compartment degenerative arthritis. Controversy exists over the treatment of PCL injuries, with the exception of surgical treatment of avulsion fractures. Many believe that isolated PCL injuries of any grade may be treated nonoperatively with an excellent outcome. However, PCL reconstruction is recommended for patients with grade III PCL injuries who remain symptomatic despite adequate physical therapy or if the PCL deficiency is part of a multiple-ligament knee injury.

Humans↗
PubMedDate not supplied

Measurement of posterior tibial translation in the posterior cruciate ligament-reconstructed knee: significance of the shift in the reference position.

BACKGROUND: The measurement of anterior or posterior tibial translation depends on the existence of a repeatable and accurate reference position of the knee from which the corresponding translation is measured. HYPOTHESIS: Clinical measurements of posterior tibial translation alone do not accurately reflect the laxity of posterior cruciate ligament-reconstructed knees. STUDY DESIGN: Controlled laboratory study. METHODS: Ten human cadaveric knees were tested by using a robotic/universal force-moment sensor testing system. The reference positions and the resulting kinematics in response to a 134-N anterior-posterior tibial load were determined for the intact and reconstructed knees. Posterior cruciate ligament reconstruction was performed with the graft tensioned and fixed at two different positions: 1) 90 degrees of knee flexion with a 134-N anterior tibial load and 2) full extension with no load. RESULTS: Posterior cruciate ligament reconstruction with graft fixation at full extension with no load resulted in anterior shift of the reference position by 1.5 to 3.2 mm. The reconstruction resulted in an overconstrained knee with significantly decreased total anterior-posterior translation of 2.6 to 3.2 mm. However, the posterior tibial translation measured was not significantly different from that of the intact knee. Posterior cruciate ligament reconstruction with graft fixation performed at 90 degrees of flexion with a 134-N anterior tibial load resulted in kinematics similar to those of the intact knee. CONCLUSION: Posterior tibial translations that are measured clinically can be misleading because the reference position of the knee can be shifted significantly after posterior cruciate ligament reconstruction. CLINICAL RELEVANCE: The measurement of total anterior-posterior translation may be a more accurate way to assess kinematics of the reconstructed knee.

Adult↗
PubMedDate not supplied

Clinical outcomes after combined meniscal allograft transplantation and anterior cruciate ligament reconstruction.

BACKGROUND: Concomitant meniscal transplantation performed at the time of ligament surgery may help to protect the anterior cruciate ligament graft. PURPOSE: To determine the objective and subjective clinical outcomes after combined anterior cruciate ligament reconstruction and meniscal allograft transplantation. STUDY DESIGN: Uncontrolled retrospective review. METHODS: Twenty-eight patients who underwent anterior cruciate ligament reconstruction along with meniscal transplantation were retrospectively evaluated postoperatively at an average of 2.8 years (range, 1.8 to 5.6). RESULTS: On the International Knee Documentation Committee overall subjective assessment, 86% had normal or nearly normal scores. The SF-36 physical and mental component summary scores were at higher levels than those of the patients' age- and sex-matched populations. Objectively, nearly 90% had normal or nearly normal Lachman and pivot shift test scores. The KT-1000 arthrometer testing at 30 pounds and maximum manual both demonstrated an average increased anterior translation of 1.5 mm compared with the contralateral knee. Joint space narrowing of the transplanted compartments was not significantly different from that of the contralateral knee. CONCLUSIONS: Meniscal transplantation with anterior cruciate ligament reconstruction can be a beneficial procedure in properly selected patients with either chronic anterior cruciate ligament insufficiency or failed anterior cruciate ligament surgery. Restoration of meniscal function may provide protection for the articular cartilage and improve joint stability.

Adolescent↗
PubMedDate not supplied

Biomechanical comparison of tibial inlay versus transtibial techniques for posterior cruciate ligament reconstruction: analysis of knee kinematics and graft in situ forces.

BACKGROUND: The tibial inlay technique for posterior cruciate ligament reconstruction has been proposed to provide a more anatomic reconstruction because it eliminates the sharp turn in the graft as it exits the proximal margin of the tibial tunnel in the transtibial technique. HYPOTHESIS: Reconstruction of the posterior cruciate ligament using the tibial inlay technique would more closely restore intact knee kinematics and in situ forces in the posterior cruciate ligament than would reconstruction using the transtibial technique. METHODS: Ten human cadaveric knees were tested in a controlled laboratory study. A robotic/universal force-moment sensor testing system was used to apply a 134-N posterior tibial load at 5 knee flexion angles: 0 masculine, 30 masculine, 60 masculine, 90 masculine, and 120 masculine. Four knee conditions were tested: intact, posterior cruciate ligament-deficient, and the single-bundle tibial inlay reconstruction and transtibial posterior cruciate ligament reconstruction. RESULTS: Both reconstruction techniques restored posterior tibial translations to 1.7 to 2.1 mm of the intact knee, with no statistical differences between the techniques. In response to the posterior tibial load, in situ forces in both grafts were between 7 and 39 N less than those in the intact posterior cruciate ligament, with no significant differences between the grafts. CLINICAL RELEVANCE: The study suggests that either technique may be performed with similar biomechanical results at initial fixation under these loading conditions.

Adult↗
PubMedDate not supplied

The acutely dislocated knee: evaluation and management.

Acute knee dislocations are uncommon orthopaedic injuries. Because they often spontaneously reduce before initial evaluation, the true incidence is unknown. Dislocation involves injury to multiple ligaments of the knee, resulting in multidirectional instability. Associated meniscal, osteochondral, and neurovascular injuries are often present and can complicate management. The substantial risk of associated vascular injury mandates that vascular integrity be confirmed by angiography in all suspected knee dislocations. Evaluation and initial management must be performed expeditiously to prevent limb-threatening complications. Definitive management of acute knee dislocation remains a matter of debate; however, surgical reconstruction or repair of all ligamentous injuries likely can help in achieving the return of adequate knee function. Important considerations in surgical management include surgical timing, graft selection, surgical technique, and postoperative rehabilitation.

Acute Disease↗
PubMedDate not supplied

Graft selection in anterior cruciate ligament reconstruction.

The ideal graft for use in anterior cruciate ligament reconstruction should have structural and biomechanical properties similar to those of the native ligament, permit secure fixation and rapid biologic incorporation, and limit donor site morbidity. Many options have been clinically successful, but the ideal graft remains controversial. Graft choice depends on surgeon experience and preference, tissue availability, patient activity level, comorbidities, prior surgery, and patient preference. Patellar tendon autograft, the most widely used graft source, appears to be associated with an increased incidence of anterior knee pain compared with hamstring autograft. Use of hamstring autograft is increasing. Quadriceps tendon autograft is less popular but has shown excellent clinical results with low morbidity. Improved sterilization techniques have led to increased safety and availability of allograft, although allografts have a slower rate of incorporation than do most types of autograft. No graft has clearly been shown to provide a faster return to play. However, in general, patellar tendon autografts are preferable for high-performance athletes, and hamstring autografts and allografts have some relative advantages for lower-demand individuals. No current indications exist for synthetic ligaments.

Anterior Cruciate Ligament↗