Robert L. Barrack

Resurfacing of the Patella in Total Knee Arthroplasty. A Prospective, Randomized, Double-Blind Study*

During a two-year period, eighty-nine patients who were scheduled to have a total knee arthroplasty for the treatment of degenerative osteoarthrosis were randomly assigned to one of two groups: resurfacing of the patella or retention of the patella. All patients received the same posterior cruciate-sparing prosthesis, and all operations were performed by, or under the direct supervision of, one of us. Three patients died in the early postoperative period. The remaining eighty-six patients (118 knees; fifty-eight that had had resurfacing of the patella and sixty that had not) formed the study group. They were followed for a mean of thirty months (range, twenty-four to forty-four months). Evaluation was performed with use of the clinical scoring system of The Knee Society, a patient-satisfaction questionnaire, specific questions regarding patellofemoral symptoms and function, and radiographs. All clinical evaluations were performed by the same research nurse, without the involvement of a physician, in a blinded manner (neither the nurse nor the patient had knowledge of whether the patella had been resurfaced). Preoperatively, the mean Knee Society score, on a scale ranging from 0 to 200 points, was 89.7 points (range, 33 to 132 points); postoperatively, this score improved to a mean of 172.7 points (range, 98 to 200 points). With the numbers available for study, we could detect no significant difference between the knees that had had patellar resurfacing and those that had not with regard to the over-all score (p = 0.63), the subscore for pain (p = 0.56), or the subscore for function (p = 0.77). We also could detect no difference between the treatment groups, with the numbers available, with regard to patient satisfaction or the responses to questions involving the function of the patellofemoral joint, including the ability to exit from an automobile, to rise from a chair, and to climb stairs. Thirty-two patients had bilateral total knee replacement with resurfacing of the patella in one knee and retention of the patella in the other. These patients expressed no clear preference for either knee. Eight (13 per cent) of the sixty knees that had not had resurfacing were painful anteriorly compared with four (7 per cent) of the fifty-eight that had; this was not a significant difference (p = 0.38), with the numbers available. The anterior pain that was noted postoperatively was predominantly of new onset; it had not been observed preoperatively in three of the four knees that had had resurfacing or in four of the eight that had not. No additional treatment options were offered to the patients who had anterior pain in the knee after resurfacing. However, six (10 per cent) of the sixty knees that had not had resurfacing had it subsequently, because of anterior pain in the knee, after the twelfth postoperative month (range, fifteen to thirty-nine months). The pain decreased in four of these knees. Thus, total knee arthroplasty with retention of the patella yielded clinical results that were comparable with those after total knee arthroplasty with patellar resurfacing, but it was associated with a 10 per cent prevalence of the need for subsequent resurfacing. The prevalence of anterior pain after total knee arthroplasty was not influenced by whether or not the patella had been resurfaced. The postoperative clinical scores, the postoperative development of anterior pain, and the need for subsequent resurfacing were not predicted by the presence of preoperative anterior pain, obesity, or the grade of chondromalacia observed intraoperatively. Because of the short duration of follow-up, these results should be considered preliminary. Additional follow-up is planned.

Arthroscopic treatment of transchondral talar dome fractures

Fifteen cases of transchondral talar dome fractures treated arthroscopically at the Naval Hospital in Oak land, California, were reviewed. Roentgenograms and results from clinical examination were assessed pre operatively and at regular intervals postoperatively. Clinical followup of 18 months was obtained in all cases (range, 18 to 36 months; mean, 26 months). All lesions were treated with arthroscopic excision of fragments with abrasion and/or drilling of the remaining crater. There were nine excellent results, four good, one fair, and one poor. There were no complications. Results of arthroscopic treatment compare favorably to those of open arthrotomy.

Stress and Coping Among Orthopaedic Surgery Residents and Faculty

BACKGROUND Evaluations of physicians and residents have revealed concerning levels of psychosocial dysfunction. The purposes of this study were to determine the quality of life of orthopaedic residents and faculty and to identify the risk factors for decompensation. METHODS Twenty-one orthopaedic residents and twenty-five full-time orthopaedic faculty completed a 102-question voluntary, anonymous survey. The survey consisted of three validated instruments, i.e., the Maslach Burnout Inventory, the General Health Questionnaire-12, and the Revised Dyadic Adjustment Scale; and three novel question sets addressing background and demographic information, stress reaction and management, and the balance between work and home life. Descriptive statistics, pairwise correlations, simple t tests, and Pearson and nonparametric Spearman correlations were calculated. The simple correlation coefficient was used to assess bivariate relationships. RESULTS The mean overall quality-of-life score, on a scale of 0 to 4 points, was 2.5 points for residents compared with 3.6 points for faculty members. Residents reported considerable burnout, showing a high level of emotional exhaustion and depersonalization and an average level of personal achievement, whereas faculty reported minimal burnout, showing a low level of emotional exhaustion (p < 0.0003), an average level of depersonalization (p < 0.0001), and a high level of personal achievement (p < 0.0001). Only two of twenty-five faculty members (compared with seven of twenty-one residents) scored over 4 points on the General Health Questionnaire-12, indicating significant symptomatology (p < 0.01). The majority of subjects reported that a partner or spouse showed nondistressed levels of marital adjustment and satisfaction. All residents and nine of the twenty-five faculty members had mentors but judged the resource to be minimally beneficial. Resident burnout and psychiatric morbidity correlated with weekly work hours; conflict between the commitments of work and home life; discord with faculty, nursing staff, and senior residents; debt load; and work-related stress. Protective factors included being a parent, spending time with a spouse, having a physician father, and deriving satisfaction from discussing concerns with colleagues, friends, and family. CONCLUSIONS In pursuit of our goal of determining the quality of life of orthopaedic residents and faculty, we identified a large disparity between the two groups. The resident group reported much greater levels of dysfunction particularly with regard to burnout and psychiatric morbidity. Furthermore, with regard to our second goal; our data revealed a number of risk factors for resident decompensation, most notably, increased workload, high debt levels, and discord with superiors. In addition, our research revealed that the current support interventions by the residency program, including mentoring and facilitation of spousal adjustment, are viewed as being of little help.

Functional performance of the knee after intraarticular anesthesia

Ten healthy young volunteers underwent gait analysis and tests of knee joint position sense. Gait analysis included determination of stride characteristics (veloc ity, cadence, gait cycle, stride length, and single limb support time), force plate analysis, and motion analysis of the knee. The tests of joint position sense examined the ability of the subject to reproduce passive position ing of the knee and the ability to detect change in angle at the knee joint. In a double-blind manner, 10 cc of sterile fluid were injected into the left knee of each volunteer. Five received 2% lidocaine, the other five received sterile saline. All tests were then repeated. No statistically significant difference was observed in any measurement before and after injection in either test group. It is concluded that intraarticular anesthesia has no effect on gait pattern or joint proprioception as measured. Intraarticular local anesthesia is used in sports medi cine to alleviate pain during arthroscopy of the knee under local anesthetic. The possibility of permitting damage in the early postoperative period due to loss of joint position sense is addressed in this paper. The results of this study suggest that injection of local anesthetic into a joint with an intact joint capsule does not compromise joint position sense as measured in this study. Furthermore, no change in gait parameters was observed in the functional task of ambulation. It must be noted that no conclusions regarding the loss of pain sensation can be made from the results of this study. Also, no conclusions regarding competitive ac tivity can be drawn from this study.

Exercise-related knee joint laxity

Knee injuries are the topic of increasingly sophisticated research because of the importance in professional athletics as well as increasing participation in recrea tional sports. The role of conditioning and fatigue in these injuries remains controversial. Ligaments have high collagen content, and a viscoelastic response to stress would be expected. Because of the postulated relationship between laxity and knee ligament injuries, an experiment was designed using highly motivated athletes to test the hypothesis that exercise to the point of muscular fatigue may cause laxity of the knee and thereby place athletes at risk for ligamentous injury to the knee when fatigued. An exercise protocol was designed to produce mus cle fatigue in the hamstring and quadriceps muscle groups. Knee ligament laxity was tested prior to and subsequent to the exercise protocol. To document muscle fatigue, isokinetic testing of right knee flexion and extension power was used several times during the exercise protocol. A knee arthrometer (KT-1000) was used to quantitatively document ligamentous laxity before and after exercise. The results indicated a sig nificant lengthening in knee joint laxity between preex ercise and postexercise in the left knee as measured at 15 and 20 pounds of passive displacement force ( P < 0.05). Maximum manual displacement also demon strated a significant increase in joint laxity (P = 0.02). The right knee, which had undergone isokinetic testing, demonstrated a similar tendency but without a statisti cally significant difference before and after exercise. There was no significant preexercise side to side differ ence, but postexercise measurements demonstrated a left-right difference at 15 pounds, 20 pounds, and max imum manual displacement of statistical significance (P < 0.01). These previously unreported findings document an in vivo increase in the anterior laxity of the knee joint due to exercise. The clinical implications to be drawn from this study are that more accurate clinical examination of the knee may be obtained after a short cool-down period in the knee with suspected ligamentous injury, and, in addition, athletes should be encouraged to perform vigorous warm-up exercises when entering organized sports activities after cool-down periods of greater than 15 minutes.

The natural history of conservatively treated partial anterior cruciate ligament tears

Twenty-five patients with arthroscopically proven par tial ACL tears were reviewed. All patients underwent examination under anesthesia and arthroscopy follow ing an acute injury to a previously normal knee. The percentage of tear was estimated during arthroscopy. Postoperatively, patients were treated with early motion and hamstring strengthening. Weightbearing and quad riceps rehabilitation were delayed. A detailed rating of symptoms and function was performed at a minimum of 18 months after injury, using a modification of the AOSSM ACL follow-up form. Neither the estimated percentage of ligament tear, length of followup, nor age at time of injury significantly correlated with clinical score at followup. Thirteen patients underwent partial meniscectomy at the time of original arthroscopy. Their clinical outcome was not different from those without meniscectomy. Two patients (8%) underwent ACL re construction 8 and 64 months after injury, respectively. Overall results were judged as excellent (28%), good (32%), fair (24%), and poor (16%). Only 44% were able to resume sports at their preinjury level, and 72% had activity-related symptoms.

Evidence of Reinnervation of Free Patellar Tendon Autograft Used for Anterior Cruciate Ligament Reconstruction

We studied six adult male dogs to determine whether free patellar tendon grafts show evidence of reinner vation when used for anterior cruciate ligament recon struction. Histologic return of neural elements and re turn of a somatosensory-evoked potential defined evidence of reinnervation. Before removal, the native anterior cruciate ligament was electrically stimulated with a bipolar electrode and a somatosensory-evoked potential was recorded from a scalp electrode. The ligament was excised and reconstructed using an au togenous patellar tendon graft. Somatosensory- evoked potential was attempted immediately after reconstruction. Histology for nerve endings was per formed on the native ligaments. Each animal under went repeat arthrotomy 6 months later. The grafts were isolated and somatosensory-evoked potentials were attempted. An evoked potential was seen in all six dogs before reconstruction. No graft demonstrated a somatosensory-evoked potential acutely; however, 6 months postoperatively, the somatosensory-evoked potential returned in two cases. Histology of native ligaments showed that 25% of the 100 sections eval uated contained neural elements. Of the receptors present, 89% were mechanoreceptors and 11 % were free nerve endings. Histologic examination of the graft tissue 6 months postoperatively revealed that all six grafts also contained neural elements. Mechanorecep tors and free nerve endings were present in approxi mately equal numbers in the grafts. The results of histology and somatosensory-evoked potential demon strate that in at least some cases, free patellar tendon grafts show evidence of reinnervation when used for anterior cruciate ligament reconstruction.

Thigh pain despite bone ingrowth into uncemented femoral stems.

Six porous-coated, uncemented femoral components were revised at a mean of 34.5 months for persistent thigh pain. At operation the stems were rigidly stable, difficult to extract, and showed good bony ingrowth. The four men and two women, with an average age of 59 years, all had thigh pain starting within the first year, progressive over time and unresponsive to conservative measures. These cases show that rigid fixation with good bony ingrowth does not guarantee the clinical success of a porous-coated uncemented femoral stem.

Proprioception Following Total Knee Arthroplasty With and Without the Posterior Cruciate Ligament

Proprioception was measured in two groups of patients following successful total knee arthroplasty (TKA). In one group, the posterior cruciate ligament was retained and an unconstrained cruciate-retaining total knee component was used; in the other group, the posterior cruciate ligament was excised and a cruciate-substituting design was implanted. Threshold to detection of passive motion was quantified as a measure of proprioception. The degree of preoperative arthritis was objectively classified according to Resnick and Niwoyama. There was no difference in threshold to detection of passive motion in cruciate-retaining versus cruciate-substituting TKA. In patients with a moderate grade of arthritis before surgery, the postoperative scores were virtually identical. When the grade of preoperative arthritis was severe, patients with cruciate-substituting TKAs performed significantly better than those with cruciate-retaining TKAs.

GRAM STAIN DETECTION OF INFECTION DURING REVISION ARTHROPLASTY

We reviewed 194 revision arthroplasties of the hip and knee performed over a ten-year period. The results of intraoperative Gram staining were available in 169 (87%). Thirty-two were found to be infected (11 hips and 21 knees) and 137 had no evidence of infection. Intraoperative Gram staining was negative in all 169 cases. The method therefore had a sensitivity of 0% for detecting infection. We conclude that the absence of organisms on intraoperative Gram staining during revision arthroplasty does not confirm the absence of infection.