Torbjørn Grøntvedt

Autologous Chondrocyte Implantation Compared with Microfracture in the Knee: A Randomized Trial

BACKGROUND New methods have been used, with promising results, to treat full-thickness cartilage defects. The objective of the present study was to compare autologous chondrocyte implantation with microfracture in a randomized trial. We are not aware of any previous randomized studies comparing these methods. METHODS Eighty patients without general osteoarthritis who had a single symptomatic cartilage defect on the femoral condyle in a stable knee were treated with autologous chondrocyte implantation or microfracture (forty in each group). We used the International Cartilage Repair Society, Lysholm, Short Form-36 (SF-36), and Tegner forms to collect data. An independent observer performed a follow-up examination at twelve and twenty-four months. Two years postoperatively, arthroscopy with biopsy for histological evaluation was carried out. The histological evaluation was done by a pathologist and a clinical scientist, both of whom were blinded to each patients treatment. RESULTS In general, there were small differences between the two treatment groups. At two years, both groups had significant clinical improvement. According to the SF-36 physical component score at two years postoperatively, the improvement in the microfracture group was significantly better than that in the autologous chondrocyte implantation group (p = 0.004). Younger and more active patients did better in both groups. There were two failures in the autologous chondrocyte implantation group and one in the microfracture group. No serious complications were reported. Biopsy specimens were obtained from 84% of the patients, and histological evaluation of repair tissues showed no significant differences between the two groups. We did not find any association between the histological quality of the tissue and the clinical outcome according to the scores on the Lysholm or SF-36 form or the visual analog scale. CONCLUSIONS Both methods had acceptable short-term clinical results. There was no significant difference in macroscopic or histological results between the two treatment groups and no association between the histological findings and the clinical outcome at the two-year time-point. LEVEL OF EVIDENCE Therapeutic study, Level I-1a (randomized controlled trial [significant difference]). See Instructions to Authors for a complete description of levels of evidence.

A randomized trial comparing autologous chondrocyte implantation with microfracture. Findings at five years.

BACKGROUND The optimal treatment for cartilage lesions has not yet been established. The objective of this randomized trial was to compare autologous chondrocyte implantation with microfracture. This paper represents an update, with presentation of the clinical results at five years. METHODS Eighty patients who had a single chronic symptomatic cartilage defect on the femoral condyle in a stable knee without general osteoarthritis were included in the study. Forty patients were treated with autologous chondrocyte implantation, and forty were treated with microfracture. We used the International Cartilage Repair Society, Lysholm, Short Form-36, and Tegner forms to collect clinical data, and radiographs were evaluated with use of the Kellgren and Lawrence grading system. RESULTS At two and five years, both groups had significant clinical improvement compared with the preoperative status. At the five-year follow-up interval, there were nine failures (23%) in both groups compared with two failures of the autologous chondrocyte implantation and one failure of the microfracture treatment at two years. Younger patients did better in both groups. We did not find a correlation between histological quality and clinical outcome. However, none of the patients with the best-quality cartilage (predominantly hyaline) at the two-year mark had a later failure. One-third of the patients in both groups had radiographic evidence of early osteoarthritis at five years. CONCLUSIONS Both methods provided satisfactory results in 77% of the patients at five years. There was no significant difference in the clinical and radiographic results between the two treatment groups and no correlation between the histological findings and the clinical outcome. One-third of the patients had early radiographic signs of osteoarthritis five years after the surgery. Further long-term follow-up is needed to determine if one method is better than the other and to study the progression of osteoarthritis.

Comparison of Failure Strength Between Metallic and Absorbable Interference Screws Influence of Insertion Torque, Tunnel-Bone Block Gap, Bone Mineral Density, and Interference

Because of the good initial fixation strength of interfer ence screws used in anterior cruciate ligament recon struction, metal interference screws have become the standard method for fixation of bone-patellar tendon- bone grafts. To avoid some of the complications with metal screws, a bioabsorbable interference screw was developed. Data on fixation strength in older human cadavers indicate a similar failure strength between bioabsorbable and metal screws. We studied the fail ure mechanisms, insertion torques, and fixation strengths of absorbable and metal interference screws in cadaveric knees from young and middle-aged do nors. With identical gap and screw size, the mean insertion torque for the metal screws (mean, 1.5 N-m; SD, 0.8) was significantly higher than for the absorb able screws (mean, 0.3 N-m; SD, 0.19). The mean failure load for the metal screws (mean 640 N; SD, 201) was also significantly higher than for the absorb able screws (mean, 418 N; SD, 118).

Fixation strength of interference screw fixation in bovine, young human, and elderly human cadaver knees: Influence of insertion torque, tunnel-bone block gap, and interference

A failure analysis of interference screw fixation was performed to test the hypothesis that bovine and/or elderly human cadavers are appropriate models for bonepatellar tendon-bone anterior cruciate ligament (ACL) reconstruction fixation studies. Failure mode is an important criterion for validating experimental models. The bovine, young human, and elderly human failure loads were 799±261 N, 655±186 N, and 382±118 N, respectively, and the failure modes were 75%, 69%, and 30% tissue failures, respectively. The similarities between the bovine and young human models in failure loads and failure modes indicate that bovine models are appropriate for ACL reconstruction fixation studies. The statistically significant differences between the young human and elderly human models in failure loads and failure modes indicate that elderly human cadavers are not an appropriate model for ACL reconstruction fixation studies. The differences in failure modes are consistent with previous studies using elderly human cadavers in which the predominant failure mode was bone block pullout. The tissue failures observed in the bovine and young human models contradict previous studies suggesting fixation strength is the weakest link in bone-patellar tendon-bone ACL reconstruction. Results of linear regression modeling showed statistically significant correlations between insertion torque and failure load (R2=0.44,P<0.0001) and interference (defined as the screw outer thread diameter minus the tunnel-bone block gap) and insertion torque (R2=0.18,P=0.003) when data from all models was combined. Results for the bovine model multiple regression showed a statistically significant regression of insertion torque (linear) and interference (quadritic) versus failure load (R2=0.56,P=0.02). Regression slopes for screw diameter (P=0.52) and gap size (P=1.00) were not statistically significant. These results indicate that insertion torque and interference are independent predictors of failure load and should be included in future interference screw studies in addition to bone block dimensions, tunnel size, gap size, and screw diameter. Clinicians may consider using insertion torque and interference as indicators of postoperative graft fixation regarding rehabilitation decisions.

A sixteen-year follow-up of three operative techniques for the treatment of acute ruptures of the anterior cruciate ligament.

BACKGROUND This study compares three surgical procedures that we used in the past to treat ruptures of the anterior cruciate ligament: acute primary repair, acute repair augmented with a synthetic ligament-augmentation device, and acute repair augmented with autologous bone-patellar tendon-bone graft. METHODS This is the third report on a group of patients who were randomized to the three different procedures between 1986 and 1988. There were fifty patients in each group. The patients were evaluated prospectively at one, two, five, and sixteen years with use of the Tegner activity score and the Lysholm functional score. Stability of the knee was assessed with clinical examination and with use of the KT-1000 arthrometer. RESULTS One hundred and twenty-nine (88%) of the 147 patients who were available for follow-up completed the study. Eleven patients (24%) who had a primary repair, four patients (10%) who had repair with a ligament augmentation device, and one patient (2%) who had augmentation with autologous bone-patellar tendon-bone graft underwent anterior cruciate ligament revisions between the primary operation and the sixteen-year follow-up examination. The rate of revision was ten times higher in the group that had primary repair than in the group that had repair with bone-patellar tendon-bone graft (p = 0.003). In the remaining patients, those who had repair with a bone-patellar tendon-bone graft had significantly more stable knees than those who had repair with a ligament augmentation device, as measured by the Lachman test (p = 0.026). Nine (11%) of the eighty-five patients for whom data were available had osteoarthritis in the primarily reconstructed knee, and three patients (3.5%) had osteoarthritis in the contralateral knee at sixteen years (p = 0.001); no difference was noted among the three groups. The mean Lysholm score at sixteen years was 88 points for the knees that had primary repair, 85 points for those that had repair with the ligament augmentation device, and 90 points for those managed with a bone-patellar tendon-bone graft (p = 0.286). CONCLUSIONS At long-term (sixteen-year) follow-up, the rate of revision anterior cruciate ligament surgery is much higher following primary repair than after primary repair augmented by a bone-patellar tendon-bone graft. It can be expected that approximately 10% of patients undergoing anterior cruciate ligament reconstruction acutely will have osteoarthritis develop in the reconstructed knee. We no longer perform any of these surgical techniques as open procedures.

A Prospective, Randomized Study of Three Operations for Acute Rupture of the Anterior Cruciate Ligament. Five-Year Follow-up of One Hundred and Thirty-one Patients*

A five-year, prospective, randomized follow-up study was done to compare three methods for repair of a rupture of the anterior cruciate ligament of the knee: acute primary repair (Group 1), acute repair with a synthetic ligament-augmentation device (Group 2), and acute repair augmented with an autologous bone-patellar ligament-bone graft (Group 3). One hundred and fifty patients who had an acute rupture of the anterior cruciate ligament were randomized to one of the three repair groups, with fifty patients in each group. The patients were between sixteen and fifty years old (mean, twenty-nine years old). All patients had the operation within ten days after the injury. The rehabilitation protocol was identical for each group. The patients were evaluated prospectively at one, two, and five years with use of the Tegner scoring system for level of activity and the scoring system of Lysholm and Gillquist for function, and the stability of the knee was assessed with clinical examination and with use of the KT-1000 arthrometer. One hundred and thirty-one patients completed the study and ten other patients were known to have had a failure of the procedure, a 94 per cent rate of follow-up. All three groups had a lower level of activity at the five-year follow-up evaluation than they had had before the injury. The patients who had had augmentation with a patellar-ligament graft had a significantly higher mean level of activity at two years than those who had had non-augmented repair (p = 0.002) and those who had had repair with a synthetic ligament-augmentation device (p = 0.01). They also had a significantly higher mean level of function at two years than those who had had non-augmented repair (p = 0.0001) and those who had had repair with a synthetic ligament-augmentation device (p = 0.03) and a significantly higher mean level of function at five years than those who had had non-augmented repair (p = 0.004). The ability to attain full extension improved significantly in all three groups during the five-year follow-up period; the highest gains occurred in the group that had had augmentation with a patellar-ligament graft. Rotatory and anterior instability progressively increased during the follow-up period for all three groups. At one, two, and five years, the knees that had had repair with a patellar-ligament graft were significantly more stable than those that had had non-augmented repair and those that had had repair with a ligament-augmentation device (p < 0.0001 to p = 0.03). The findings of this study reinforce the conclusions of our two-year follow-up report that a non-augmented primary repair should not be performed, a repair with a ligament-augmentation device has an unacceptably high rate of failure (more than one-third of the patients), and a repair that is augmented with the patellar ligament has the best outcome.

Anterior Cruciate Ligament Reconstruction with and without a Ligament Augmentation Device Results at 8-Year Follow-up

Background Ligament augmentation devices have been used in anterior cruciate ligament reconstruction since the suggestion of Kennedy et al. in 1980 that such devices would allow grafts to heal faster and more safely. Hypothesis Patients who had augmentation will have better outcomes after 8 years. Study Design Prospective randomized case control study. Methods Between 1991 and 1993, 100 patients were randomized to groups undergoing anterior cruciate ligament reconstruction with bone-patellar tendon-bone grafts with (49) or without (51) use of a Kennedy ligament augmentation device. Of these 100 patients, 94 were examined at an average of 8 years after surgery. Fifteen patients were excluded because of rupture in the other knee and 11 because of rerupture in the same knee. Results Of the remaining 68 patients, the mean Lysholm function score was 84 in the augmentation group and 87 in the control group. There was a statistically significant relationship between preoperatively detected cartilage injury and osteoarthritis. Almost half of the patients had developed osteoarthritis. We observed no significant difference between the two groups concerning rerupture rate, Lysholm or Lachman test scores, or KT-1000 arthrometer measurements. Conclusions We found no positive long-term effects supporting the use of augmentation in anterior cruciate ligament reconstruction.

Magnetic Resonance Imaging Analysis of Bioabsorbable Interference Screws Used for Fixation of Bone–Patellar Tendon–Bone Autografts in Endoscopic Reconstruction of the Anterior Cruciate Ligament

Background Metal interference screws can cause problems if revision is needed and can interfere with magnetic resonance imaging. Bioabsorbable screws have been developed to prevent these problems, but the rate of resorption and integration is not well understood. Hypothesis Poly-L-lactic acid interference screws will be resorbed 2 years after anterior cruciate ligament reconstruction. Study Design Case series; Level of evidence, 4. Methods The study group consisted of 19 patients with isolated anterior cruciate ligament ruptures reconstructed with bone-patellar tendon-bone autografts fixed with poly-L-lactic acid interference screws using an endoscopic technique. Magnetic resonance imaging was used to evaluate resorption of the screws, bony integration of the screws, and integration of the bone blocks after 2 years. Results At 2 years, the mean reduction in the volume of the femoral screws was 64% and of the tibial screw was 63%. Bony integration of the femoral bone block was considered good in 17 patients and fair in 2 patients. Integration of the tibial bone block was considered good in 16 patients and fair in 1 patient who demonstrated widening of the tibial tunnel. Osteolysis around the screws was seen in 3 patients in the femur and none in the tibia. Conclusion The mean reduction in volume of the poly-L-lactic acid screws as measured by magnetic resonance imaging after 2 years was approximately two thirds. The integration of the bone blocks was considered good in 90% of the patients. Osteolysis around the screws was visible in 16% of the patients. Clinical Relevance Two years after ACL reconstruction using poly-L-lactic acid interference screws, the surgeon can expect to find approximately one third of the volume of the screw remaining in the bone tunnels.

A Randomized Multicenter Trial Comparing Autologous Chondrocyte Implantation with Microfracture: Long-term Follow-up at 14 to 15 Years.

BACKGROUND The management of cartilage and osteochondral lesions in the knee remains problematic and controversial. Our group reported the 2-year and 5-year results of a randomized controlled trial comparing autologous chondrocyte implantation (ACI) and microfracture in patients with focal femoral cartilage injuries. The objective of the present study was to report the long-term results. METHODS Eighty patients with a single symptomatic chronic cartilage defect on the femoral condyle without general osteoarthritis were included in the study at the time of the index operation (January 1999 to February 2000). We used the International Cartilage Repair Society (ICRS), Lysholm, Short Form-36 (SF-36), and Tegner forms to collect data at the time of inclusion and at follow-up evaluations. Standing weight-bearing radiographs were evaluated for evidence of osteoarthritis according to the method described by Kellgren and Lawrence. For the long-term follow-up in 2014, we used the Synaflexer frame to standardize the radiographs. The operation was considered to have failed if a reoperation was performed because of symptoms from a lack of healing of the treated defect. RESULTS At the long-term follow-up evaluation, no significant differences between the treatment groups were detected with respect to the results on the clinical scoring systems. At the 15-year evaluation, there were 17 failures in the ACI group compared with 13 in the microfracture group. We observed that more total knee replacements were needed in the ACI group than in the microfracture group (6 compared with 3). The surviving patients in both groups, i.e., those who had not had a failure, had significant improvement in the clinical scores compared with baseline. Fifty-seven percent of the surviving patients in the ACI group and 48% of such patients in the microfracture group had radiographic evidence of early osteoarthritis (a Kellgren and Lawrence grade of ≥2); the difference was not significant. CONCLUSIONS The survivors in both groups improved their clinical scores in the short, medium, and long-term evaluations, and no significant difference between the groups was found at the long-term follow-up. The risk of treatment failure and the frequency of radiographic osteoarthritis are problematic. Our findings raise serious concerns regarding the efficacy of these procedures in delaying osteoarthritis and preventing further surgery. Continued basic and clinical research is needed in this field. LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Endoscopic Reconstruction of the Anterior Cruciate Ligament Using Bone–Patellar Tendon–Bone Grafts Fixed With Bioabsorbable or Metal Interference Screws A Prospective Randomized Study of the Clinical Outcome

Background During the past decade, bioabsorbable interference screws have become increasingly popular in endoscopic reconstructions of the anterior cruciate ligament. With these screws, there is no need for a second operation for removal and no complicating factor if later revision surgery is necessary. Several pullout studies have found similar results between metal and bioabsorbable interference screws; however, few studies have investigated the clinical outcome. Hypothesis There is no difference in the clinical outcome of bioabsorbable interference screws compared with metal screws. Study Design Randomized controlled clinical trial; Level of evidence, 1. Methods Forty-one patients were randomized for the use of either metal interference screws (20 patients) or bioabsorbable poly-L-lactic acid screws (21 patients). The patients were followed with clinical examinations at 6, 12, and 24 weeks and at 1 and 2 years postoperatively. Results Subjective knee function was better in the patients in the metal screw group; they had less pain at rest, a higher Tegner score, a higher Lysholm score, and better subjective knee function at 2 years compared to the bioabsorbable screw group. However, there was no difference in stability between the groups. Conclusion and Clinical Relevance Because of the inferior results in the bioabsorbable screw group in our study, and until larger studies show otherwise, we do not find the advantages of using bioabsorbable screws sufficient to warrant the routine use of poly-L-lactic acid screws in anterior cruciate ligament reconstructions.