Role of the posterior cruciate ligament in total knee arthroplasty

Accumulating evidence indicates that protein kinase C (PKC)-dependent, Ca2+-independent smooth muscle contraction plays the central role in the occurrence of chronic vasospasm following aneurysmal subarachnoid hemorrhage. As far as we know, the nitric oxide/ cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) system comprises the most efficacious inhibitory mechanism against the PKC-dependent contractile mechanism, and the myogenic tonus of normal cerebral arteries is thought to be maintained on the balance between these systems. Recent studies indicate that in spastic cerebral arteries, the rise in the intracellular diacylglycerol level causes PKC activation presumably owing to the overexpression of endothelin (ET)-1 as well as the generation of free radicals, whereas the cGMP level is inversely reduced owing to the inactivation of soluble guanylate cyclase through some as yet unknown mechanism. The resultant loss of balance between the two systems is considered to culminate in the occurrence of chronic vasospasm lasting for nearly 2 weeks. Based on the above concept, recent papers concerning the effects of reactive oxygen species on the arterial smooth muscle, alterations of various membrane ion channels, particularly of adenosine triphospate (ATP)-activated potassium channels in spastic arteries, the preventive effects of ET antagonists on vasospasm, and the causative role of ET-1 were reviewed in the present article. The roles of the above spasmogenic factors or mechanisms may be more clearly understood on the basis of the antagonistic interrelation between the PKC and the PKG systems, which exert diverse influences on the force-generating system as well as on its multifarious regulatory mechanisms in smooth muscle cells.     

Flexion instability after primary posterior cruciate retaining total knee arthroplasty

Between 1990 and 1995, 25 painful primary posterior cruciate ligament retaining total knee arthroplasties were revised for flexion instability. These patients shared typical clinical presentations that included a sense of instability without frank giving way, recurrent knee joint effusion, soft tissue tenderness involving the pes anserine tendons and the retinacular tissue, posterior instability of 2+ or 3+ with a posterior drawer or a posterior sag sign at 90 degrees flexion, and above average motion of their total knee arthroplasty. The primary total knee arthroplasty was performed for osteoarthritis in 23 patients and rheumatoid arthritis in two patients. There were 13 male and 12 female patients and their mean age was 65 years (range, 35-77 years). Before the revision operation, Knee Society knee scores averaged 45 points (range, 17-68 points) and function scores averaged 42 points (range, 0-60 points). Twenty-two of the knee replacements were revised to posterior stabilized implants and three underwent tibial polyethylene liner exchange only. Nineteen of the 22 knee replacements revised to a posterior stabilized implant were improved markedly after the revision surgery. Only one of three knee replacements that underwent tibial polyethylene exchange was improved. After the revision for flexion instability, Knee Society knee scores averaged 90 points (range, 82-99 points) and function scores averaged 75 points (range, 45-100 points) for the 20 knees with a successful outcome. This study suggests that flexion instability can be a cause of persistent pain and functional impairment after posterior cruciate ligament retaining total knee arthroplasty. A revision operation that focuses on balancing the flexion and extension spaces, in conjunction with a posterior stabilized knee implant, seems to be a reliable treatment for symptomatic flexion instability after posterior cruciate retaining total knee arthroplasty.     

Early, incapacitating instability of posterior cruciate ligament-retaining total knee arthroplasty

Numerous studies indicate that total knee arthroplasty (TKA) achieves excellent long-term success whether the posterior cruciate ligament (PCL) is saved or excised. In 13 patients, 16 PCL-retaining TKAs were identified with incapacitating instability secondary to early PCL deficiency. Patients with clinical PCL insufficiency present with a triad of subjective complaints: persistent swelling/effusions, anterior knee pain, and giving-way or instability episodes with activities of daily living. Of 13 patients, 12 had at least three postoperative visits with identical subjective complaints before PCL deficiency was diagnosed. On examination all patients exhibited effusion, posterior sag, positive quadriceps active test, and a visible anterior translation of the tibia on the femur while extending the leg from a seated, 90 degree flexed position. This sign has not been previously described to our knowledge but was present in all of our study patients. No patients had radiographic evidence of loosening or osteolysis. Joint aspiration was negative for infection in all patients. No patient had lateral patellofemoral maltracking. By radiographic measurement, the PCL-deficient knees had an average joint line elevation of 10.3 mm, compared with well-functioning TKAs which had an average joint line elevation of 5.0 mm. There was no correlation of PCL deficiency with excessive proximal tibial resection. Nonsurgical intervention provided no improvement in pain or instability. Six patients had improvement of pain, effusion, and stability after revision to a cruciate-substituting implant. We believe that this complication occurs more frequently than is currently being identified and should be considered in problem TKAs with normal radiographs.     

Value of posterior cruciate ligament index in the diagnosis of anterior cruciate ligament injuries

Several EF-hand recoverin mutants were obtained and their abilities to bind to photoreceptor membranes and to inhibit rhodopsin kinase were determined. The mutants with the 'spoiled' 2nd, 3rd or (2nd+3rd) EF-hand structures did not act upon the kinase activity in the microM range of Ca2+ concentrations. Mutations of the 4th EF hand, which 'repaired' its Ca2+-binding activity, resulted in recoverin with three 'working' Ca2+-binding sites. The latter mutant inhibited rhodopsin kinase even more effectively than the wild-type recoverin, containing two working Ca2+-binding structures.     

Hinged total knee arthroplasty

Analysis of an on-going prospective study of seventy-seven hinged total knee arthroplasties in sixty-seven patients revealed that most patients had improvement in function, although major complications occurred in eighteen knees (23.4 per cent. These complications included sepsis, loosening, patellar tendon rupture, peroneal palsy, and patellar subluxation. Eight of nine knees with deep sepsis required removal of the prosthesis, and three of sixteen knees with patellar pain required realignment of the quadriceps. When prosthetic failure occurred, salvage of a functional extremity was difficult. Hinged total arthroplasty is not without its problems, and a cautious approach to its use is indicated. Whenever possible, a moderately constrained replacement arthroplasty should be considered.     

Hybrid total knee arthroplasty

A prospective study of a hybrid total knee arthroplasty (TKA) with an uncemented femoral component and cemented tibial and patellar components was performed to combine the advantage of a press-fit femur while avoiding the problems in uncemented tibial and patellar implants. A total of 329 posterior cruciate-preserving TKA were studied at an average of 4.7 years after surgery: 84% of the knees had at most mild or occasional pain, 68% had good or excellent knee scores, and 62% could walk more than 1000 m. The function scores were 40% good or excellent in this collective, with an average age of 69.4 years at surgery. The component position and alignment were biomechanically correct. Radiolucent lines were observed regularly at the edges of the tibial and femoral components. There were no revisions for aseptic loosening. Hybrid TKA provides good results comparable to cemented TKA.     

Polycentric total knee arthroplasty

Polycentric total knee arthroplasty in 56 patients provided significant relief of pain in 90.7% and a stable knee in 92.7%. Postoperative increase in range of motion averaged 13.7 degrees for all patients (18.5 degrees in rheumatoid arthritis and 8.7 degrees in degenerative arthritis). This increase in excursion is attributed to the design of the prosthesis, a vigorous postoperative rehabilitation program, and careful surgical technic. A failure rate of 12.7% was due to infection, mechanical instability and unexplained pain. Contraindications to surgery and technical recommendations are noted.     

Analysis of proprioception in the posterior cruciate ligament-deficient knee

Preseptal cellulitis has a typically benign course when treated with antibiotics, the clinical course depending on age of the patient, aetiology and the causative organism. In this study, 14 cases of preseptal cellulitis are documented with the age ranging from 2 to 55 years. The organisms isolated were Staphylococcus aureus (7 cases), Streptococcus pyogenes (2 cases) and Pseudomonas aeruginosa (1 case). In the remaining four patients no organism could be identified. All except four patients were cured within 6 weeks. Complications seen included lagophthalmos, lid abscess, cicatricial ectropion and lid necrosis in one patient each. The prognosis for preseptal cellulitis is good with appropriate antibiotics and surgical therapy.     

Effect of polyethylene quality on wear in total knee arthroplasty

During evaluation of 29 Ortholoc II tibial polyethylene components retrieved at revision surgery, the authors noticed that components with a lot number prefix of CP (Custom Product) consistently had minimal wear and those with a standard lot number had severe wear, regardless of patient age, weight, gender, and activity level. Non-CP components had earlier and more severe wear than CP components in service for the same amount of time. Microscopic evaluation of the polyethylene revealed major differences in the material. Large subsurface cracks, fusion defects, and intergranular cracks were present in the non-CP components, but these defects were minimal or nonexistent in the CP components. The components with defects had a significantly greater delamination rate than those without defects. Gamma irradiation did not seem to accelerate wear or delamination, because irradiated components that had minimal microscopic signs of fusion defects performed as well as nonirradiated components with a similar microscopic appearance. The manufacturing details disclosed that different materials and processing methods were used for the 2 groups. The results from this study suggest that improved quality control of polyethylene material would greatly decrease wear and delamination of total knee arthroplasty components.     

Evaluation and treatment of posterior cruciate ligament injuries

Twenty-eight low median nerve injuries and 23 low ulnar nerve injuries were repaired using intraneural fascicular dissection and electrical fascicular orientation. Eleven freshly lacerated nerves were seen within 48 hours after injury; 40 nerve lacerations were chronic. Fascicular orientation between sensory and motor fascicles at the proximal nerve end could be accurately differentiated in 47 nerves (92%) independent of whether it was acute or chronic. At the distal nerve end in fresh lacerations, the motor fascicles could be determined conclusively by muscle contraction with sequential electrical stimulation of the fascicles. In chronic nerve lacerations, the distal fascicles could be estimated anatomically after internal neurolysis. After fascicular orientation, nerves were repaired with end-to-end group fascicular suture or interfascicular sural nerve grafting. Twenty-four nerves repaired with end-to-end suture and 13 nerves repaired with nerve grafting were monitored more than 25 months. Satisfactory sensory results (i.e., S3+ or S4 functions) were obtained in 29 nerves (78%) and M4 or M5 motor functions were achieved in 29 nerves (78%). There were no patients who needed additional tendon transfers to reconstruct thumb opposition or to correct claw finger deformity. These results suggest that low median or ulnar nerve lacerations, whether acute or chronic, partial or complete, may be successfully repaired with the aid of electrical fascicular orientation with or without intraneural fascicular dissection.     

In-situ forces in the human posterior cruciate ligament in response to posterior tibial loading

The presence of human cytomegalovirus (HCMV) DNA in liver, spleen, and kidney samples of HCMV-seropositive trauma victims during latency was demonstrated by polymerase chain reaction (PCR), using primers reactive with the major immediate early gene exon 4 and the structural gene pp150. Sequence analysis of the PCR amplificates showed more than 95% homology with the reference HCMV strain AD169. The few mutations observed were mostly distributed randomly. In one subject two types of the MIE-4 gene were detected, and in another subject two types of the pp150 gene were found, suggesting that different strains of HCMV can be found in organs of the same patient during latency.     

Survivorship of cemented total knee arthroplasty

The survivorship method of analysis was used to compare the failure rate and overall success of 2629 cemented primary total knee arthroplasties during a 22-year period by the senior surgeon. There were 215 Total Condylar prostheses with a polyethylene tibia, 265 of the Posterior Stabilized type with an all polyethylene tibia, 2036 Posterior Stabilized with a metal backed tibial component, 49 Posterior Stabilized with modular augmented components, and 64 with the Constrained Condylar system. Failure was considered revision or planned revision. The Total Condylar series had an average annual failure rate of 0.46% and a 21-year success rate of 90.77%. The Posterior Stabilized prosthesis with an all polyethylene tibia had an average annual rate of failure of 0.38% and a 16-year success rate of 94.10%, and this prosthesis with a metal backed tibial component had an annual failure rate of 0.14% and a 14-year success rate of 98.10%. The Posterior Stabilized series with modular components had an average annual rate of failure of 0.59% and a 10-year success rate of 93.63%. The Constrained Condylar knee series had an average annual failure rate of 0.26% and a 7-year success rate of 98.12%. This review represents a retrospective analysis of consecutive series of cemented, total knee arthroplasties, whose annual failure and success rates were done during differing time spans. The overall success rate was not influenced by gender, age, diagnosis, or percentage of ideal body weight. Failure was considered revision or planned revision. The best and worse case scenarios were calculated for each series. Long term results of cemented, total knee arthroplasty with a relatively conforming articular surface has been shown to be a reliable procedure with excellent survivorship.     

The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion

OBJECTIVE: To assess the outcome of 31 patients treated in a day and semi-residential psychotherapy setting. METHOD: Patients had moderate to severe personality difficulties and were referred when current therapy was insufficient or because of the severity of their problems. Eighty-one percent had a Cluster C and 19% a Cluster B (Borderline) Personality Disorder diagnosis (DSM-III-R). Therapy was psychodynamically and feministin-formed and included a sociopolitical dimension. Rating scales used were the Symptom Checklist 90, Goal Attainment Scale, Global Assessment Scale and measures of health resource usage, which were completed pre-treatment, post-treatment and at 4-, 12- and 24-month follow-up. RESULTS: Mean duration of therapy was 4 months (68 therapy days). All clinical rating scales demonstrated marked improvements following treatment (p < 0.0001) which were sustained at 2-year follow-up. There were also improvements of health resource usage. CONCLUSIONS: The results document the clinical efficacy of psychotherapy in this setting, provide support for the philosophy of practice, and suggest that psychotherapy outcome can be evaluated at reasonable financial cost in many settings.     

Flexion space configuration in total knee arthroplasty

Equal resection of the posterior femoral condyles combined with a 90 degree tibial resection results in a trapezoidal flexion space. Two groups of patients were studied; in one group, the flexion space was allowed to remain trapezoidal, whereas in the other group, the anteroposterior femoral resections were externally rotated to allow rectangularization of the flexion space. In the second group, the range of flexion was increased and the incidence of medial tibial pain and zone I radiolucencies decreased. Other than for knees in a hypervalgus position before surgery, the mean amount of rotation required was 3 degrees +/- 0.2 degrees.     

Patellofemoral complications in symmetrical total knee arthroplasty

A review of 356 Kinemax (Howmedica, Inc, Rutherford, NJ) cemented posterior cruciate ligament-retaining condylar total knee arthroplasties employing a symmetrical femoral component articulating with a medially offset symmetrical dome patella component was carried out to examine the results and determine the incidence and nature of the patellofemoral complications. Follow-up was from 3 to 8 years, with a mean of 5.1 years. A review of patellofemoral complications in previously reported homogeneous series of symmetrical and asymmetrical implants is presented. Mean postoperative Knee Society scores improved to 91, function scores to 86, and Hospital of Special Surgery scores to 90 yielding 95% good and excellent results. Mean postoperative range of motion was -1.5 degrees extension to 113 degrees flexion. There were five patellofemoral complications (1.4%), including two symptomatic subluxations, two distal pole avulsion fractures, and one lateral facet fracture. There were two reoperations necessary for patellofemoral problems (0.56%), one to correct subluxation and one for excision of the fractured lateral facet. These rates are lower than those previously reported for asymmetrical implants as well as current and phased-out symmetrical designs of total knee arthroplasty in the intermediate term. This review suggests that cemented total knee arthroplasty with symmetrical patellofemoral resurfacing with an offset patella dome and posterior cruciate ligament retention yields low patellofemoral complications and reoperations. The symmetrical femoral component appears to be a satisfactory compromise of "normal" femoral anatomy, which decreases inventory and cost without adversely affecting patellofemoral function and complications.     

Effect of patellar meniscus on patellofemoral contact stress in total knee arthroplasty

A wide variety of surgical procedures and implant materials have been used to satisfy the growing demand of patients for lip augmentation. The authors describe our experience with Alloderm (LifeCell Corp, The Woodlands, TX). It has proven to be a safe and effective means of offering mild to moderate augmentation of the lips.     

Early experience with total knee arthroplasty

Early results of 76 geometric total knee replacements were reviewed with assistance from computer analysis. A 92% patient follow-up for one to three years showed an overall satisfactory result with substantial improvement, especially in relief of severe pain. However, several problems are noted, including fractures beneath the tibial plateau and loosening. The long-term results are still unknown. The indications for total knee replacements should remain conservative until long-term results and experience have been achieved.     

Radionuclide imaging of the knee with chronic anterior cruciate ligament tear

We studied the results of bone scans in 50 consecutive patients with symptomatic, unilateral, chronic anterior cruciate ligament (ACL) tears. All patients had failed conservative therapy and underwent radionuclide imaging of the knee prior to arthroscopic ACL reconstruction. The scintigraphic activity in each of the three knee compartments was quantitatively scaled from 1 (normal scintigraphic activity) to 4 (marked activity). Quantitative activity in each of the three compartments was correlated with plain radiographic, arthroscopic, and clinical findings. All but four of the scans (92%) showed abnormal scintigraphic activity. The quantitative activity was highest overall in the medial compartment (2.9), followed by the lateral (2.4) and patellofemoral compartments (1.9). In the subgroup of patients with normal menisci (10 patients), most of the abnormal activity was in the lateral compartment (2.9), implying that when the medial meniscus remains competent in the presence of a torn ACL, there is increased stress on the lateral compartment. There was little correlation with scintigraphy and roentgenographic changes, except in the presence of moderate or severe radiographic degenerative arthritis. Similarly, there was little correlation between increased scintigraphic activity and chondromalacia. These results provide a baseline for future studies that use scintigraphic imaging in monitoring restoration of bone homeostasis following ACL reconstruction.     

Eccentric knee flexor torque following anterior cruciate ligament surgery

The purposes of this study were to compare eccentric knee flexor torque and muscle activation in the limbs of normal (NOR) subjects and in subjects who had undergone unilateral ACI, autograft surgical reconstruction (INJ) and to assess the effect of movement speed on EMG/ torque ratios and eccentric-concentric actions. Fourteen subjects (7 NOR and 7 INJ) were tested for knee eccentric flexor torque and EMG activity at four isokinetic speeds (15 degrees, 30 degrees, 45 degrees and 60 degrees.s-1). Results revealed that post-surgical limbs (ACL) produced significantly less (P < 0.05) eccentric torque and flexor EMG activity at 60 degrees.s-1 than uninjured (UNI) contralateral limbs. Eccentric torque rose significantly as speed increased from 45 degrees to 60 degrees.s-1 for surgical group uninjured limbs and NOR group left and right limbs. Eccentric flexor torque increased with speed for both groups and approximated equality with concentric extensor torque at 60 degrees.s-1 for INJ group ACL and UNI limbs. Concentric flexor muscle EMG/torque ratios were 30-191% greater than eccentric muscle actions across groups and speeds. The results suggest that ACL dysfunction may result in reduced eccentric flexor torque at rapid movement speeds, that eccentric flexor torque increases with movement speed and may have the capacity to counter forceful extensor concentric torque, and that eccentric muscle actions produce less muscle activation per unit force than concentric actions which may reflect reduced energy cost.