The importance of the meniscus in unstable knees. A comparative study

Performance and Return to Sports After Meniscectomy in Professional Baseball Players

BACKGROUND

Meniscal injuries are common in athletes across many sports. How professional baseball players respond to partial meniscectomy is not well documented.

PURPOSE/HYPOTHESIS

The purpose was to determine the performance and return-to-sports (RTS) rate in professional baseball players after arthroscopic partial knee meniscectomy and compare the results of partial medial meniscectomy versus partial lateral meniscectomy. The hypothesis was that there would be a high RTS rate in professional baseball players after partial meniscectomy with no difference in the RTS rate or timing of RTS between players who underwent partial medial meniscectomy versus partial lateral meniscectomy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All professional baseball players who underwent arthroscopic partial meniscectomy between 2010 and 2017 were identified using the Major League Baseball Health and Injury Tracking System database. Demographic and performance data (before and after injury) for each player were recorded. The RTS rate and timing of RTS were then compared between players who underwent partial medial meniscectomy versus partial lateral meniscectomy.

RESULTS

A total of 168 knees (168 players) underwent arthroscopic partial meniscectomy (mean age, 25 ± 5 years; 46% medial meniscectomy, 45% lateral meniscectomy, and 9% both medial and lateral meniscectomy). The most common mechanism of injury was fielding in the infield on natural grass. Injuries were spread evenly across positions: 18% catchers, 24% infielders, 20% outfielders, and 38% pitchers. The overall RTS rate was 80% (76% returned to the same or a higher level, and 4% returned to a lower level). For performance, pitchers saw significant decreases in usage but significant improvements in performance using the advanced statistics of fielding independent pitching (P < .001) and wins above replacement (P = .011). Hitters saw significant decreases in usage but increases in efficiency as seen by improvements in wins above replacement (P = .003). Of the 79 athletes who returned during the same season, the median time to return to play was 42 days.

CONCLUSION

The RTS rate after meniscectomy in professional baseball players was 80%. Player efficiency improved after surgery in pitchers and position players. No difference in the RTS rate or timing of RTS existed between players who underwent partial medial meniscectomy versus partial lateral meniscectomy.

Excellent medium-term survival of an all-inside tensionable knotted suture device justifies repair of most meniscal tears encountered during reconstructive knee ligament surgery

PURPOSE

All-inside meniscal repair devices have evolved to allow surgeons to undertake complex repairs in a timely and efficient manner. This is advantageous in active patients, where meniscus preservation is critical in preserving joint function and stability. The aim of the study was to evaluate the failure rate of all-inside meniscal repair performed in patients undergoing reconstructive ligament surgery using a particular meniscal repair device.

METHODS

Patients were identified using a single-site prospectively maintained patient registry. Primary outcome was failure, defined as return to surgery with documented failure of repair. Complication rates and functional scores were also recorded. Patients in whom meniscal repair failure was identified were further assessed, to identify any common features.

RESULTS

Over an 8-year period, 323 patients underwent meniscal repair at the time of ligament reconstruction, compared to 244 meniscectomies. Of these, 286 patients underwent repair using an all-inside suture device. One-hundred and twenty-seven repairs were to the medial meniscus only, 124 were lateral, and in 35 patients both menisci were repaired. Follow-up was to a median of 51.5 months. There were 31 (9.7%) failures reported at a median of 22 months post-operatively (IQR 13.5-41.5). Medial repair failures were seen more frequently than lateral (13.6% versus 5.6% OR 2.62 95% CI 1.17-5.88 p = 0.022). Failure of ACL reconstruction was associated with meniscal repair failure (OR 5.83 95% CI 1.55-21.95 p = 0.0039). Multi-ligament reconstruction was undertaken in 70/286 patients receiving meniscal repair and was not associated with failure (OR 1.3 95% CI 0.57-2.98 p = 0.51). Mode number of all-inside sutures used was 3 in both medial and lateral repairs (Range 1-9 lateral; 1-7 medial).

CONCLUSIONS

All-inside repair is a safe and versatile technique which can be used in the majority of meniscal tears encountered during ligament reconstruction with excellent mid-term success. Failure is seen more commonly in medial sided repairs and with failure of ACL reconstruction.

LEVEL OF EVIDENCE

IV.

MR imaging evaluation of the postoperative meniscus

MR imaging has been widely evaluated in the assessment of patients with recurrent or residual symptoms following meniscal surgery. Importantly, the causes of such symptoms may relate to failure or complication of the surgical procedure, a possible recurrent or residual meniscal tear, or may be related to other causes of joint symptoms, including tears of the contralateral meniscus, or local hyaline cartilage, or marrow abnormalities subjacent to or distant to the meniscal surgical site. The complex diagnostic issues involved in the MR imaging evaluation of the postoperative meniscus were identified in early MR imaging studies. The knowledge of the normal MR imaging appearance of the knee after the more common repair procedures will allow radiologists to recognize complications associated with such procedures. In this article, we discuss the MR imaging evaluation of the knee after meniscal surgery.

Biological aspects of early osteoarthritis

PURPOSE

Early OA primarily affects articular cartilage and involves the entire joint, including the subchondral bone, synovial membrane, menisci and periarticular structures. The aim of this review is to highlight the molecular basis and histopathological features of early OA.

METHODS

Selective review of literature.

RESULTS

Risk factors for developing early OA include, but are not limited to, a genetic predisposition, mechanical factors such as axial malalignment, and aging. In early OA, the articular cartilage surface is progressively becoming discontinuous, showing fibrillation and vertical fissures that extend not deeper than into the mid-zone of the articular cartilage, reflective of OARSI grades 1.0-3.0. Early changes in the subchondral bone comprise a progressive increase in subchondral plate and subarticular spongiosa thickness. Early OA affects not only the articular cartilage and the subchondral bone but also other structures of the joint, such as the menisci, the synovial membrane, the joint capsule, ligaments, muscles and the infrapatellar fat pad. Genetic markers or marker combinations may become useful in the future to identify early OA and patients at risk.

CONCLUSION

The high socioeconomic impact of OA suggests that a better insight into the mechanisms of early OA may be a key to develop more targeted reconstructive therapies at this first stage of the disease.

LEVEL OF EVIDENCE

Systematic review, Level II.

Long-term clinical and radiological assessment of untreated severe cartilage damage in the knee: a natural history study

We aimed to evaluate whether and to what extent an isolated deep cartilage lesion localized within the tibiofemoral and the patellofemoral joint has an impact on the clinical outcomes and osteoarthritis (OA) progression when it is left untreated. From 1991 to 1994, 4121 consecutive knee arthroscopies were performed, and 37 of them in patients with a single isolated chondral lesion of Outerbridge grade 4 located within weight-bearing areas of the femoral and tibial condyles (FT group) and patella (P group). The lesion size ranged from 2 to 4 cm(2) . Outcomes were reported at a mean 15.3-year follow-up using the Lysholm score, the Tegner activity scale and the Womac score. The mean Lysholm, Tegner and Womac score in the FT group was 87.7, 5.6 and 88.7, respectively. In the P group, it was 83.8, 4.8 and 84.6, respectively (P<0.0.5). Osteoarthritic changes were found in 39% of the patients. There was no difference in OA severity between an injured and an uninjured knee. In patients of the FT group, there was a relationship between the incidence of tibiofemoral OA and patellofemoral OA (P=0.00075). Severe isolated single chondral damage left with no treatment has a limited influence on clinical outcomes and the development of OA.

The occurrence of osteoarthritis at a minimum of ten years after reconstruction of the anterior cruciate ligament

OBJECTIVE

The objective of this study was to evaluate the incidence of radiographic osteoarthritis in the operated knee in comparison with the contralateral knee ten years after a bone-tendon bone patellar autograft ACL-reconstruction and to evaluate to which level patients regain activity ten years after reconstruction.

METHODS

Fifty-three patients with ACL instability were operated arthroscopically using the central third of the patellar tendon as a bone-tendon-bone autograft. At a minimum of 10 year follow up 28/44 patients matched the inclusion criteria and could be reached for follow-up. Evaluation included a patient satisfaction evaluation using a Visual Analog Scale, physical examination (International Knee Documentation Committee score, Tegner score, Lysholm score, KT-1000 stabilometry) and a radiological evaluation (Kellgren and Fairbanks classification).

RESULTS

The patients' satisfaction, at a mean of 10,3 year follow-up, measured with a VAS score (0-10) was high with a mean of 8.5 (range 4 to 10). The KT 1000 arthrometer laxity measurements revealed in 55% of the patients an A rating (1-2 mm), in 29% a B rating (3-5 mm) and in 16% a C rating (6-10 mm). According to the Tegner score 54% of the patients were able to perform at the same activity level as pre-operatively. The mean pre-operative Tegner score was 6.8 and the mean post-operative Tegner score was 6.0 at final follow up. The Lysholm score showed satisfactory results with a mean of 91 points (range 56 to 100). According to the Kellgren and Fairbank classifications, there is a significant difference (p < 0.05) in development of OA between the ACL injured and subsequently operated knee in comparison to the contralateral knee.

CONCLUSION

The patellar BTB ACL reconstruction does not prevent the occurrence of radiological OA after 10 years but does help the patient to regain the pre-operative level of activity.

The consequences of meniscectomy

The menisci of the knee have an important role in load-bearing and shock absorption within the joint. They may also function as secondary stabilisers, have a proprioceptive role, and aid the lubrication and nutrition of the articular cartilage. Complete or partial loss of a meniscus can have damaging effects on a knee, leading to serious long-term sequelae. This paper reviews the consequences of meniscectomy and summarises the body of evidence in the literature regarding those factors most relevant to long-term outcome.

Pathologic characteristics of the torn human meniscus

BACKGROUND

Acellular meniscus tissue is at a high risk for degeneration and retear. Information that would help surgeons predict, preoperatively, or intraoperatively which torn menisci had few viable cells could be useful in deciding which patients might be at increased risk for retear and failure of surgical repair.

HYPOTHESIS

Patient age, length of time since injury, and tear type are predictors of the cellularity of meniscus tissue.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Gross and histologic evaluation of torn meniscus tissue from 44 patients and 10 control menisci was performed.

RESULTS

The patient factors of age, time since injury, and tear type all had significant effects on the pathologic characteristics of the torn meniscus. Patients older than 40 years had lower cellularity in the torn menisci than did patients younger than 40 years (P < .01). As time since injury increased, so did the rates of DNA fragmentation in the midsubstance of the meniscus and rates of Outerbridge II changes in the adjacent cartilage. Worse meniscal histologic scores were found in menisci with degenerative and radial tear types.

CONCLUSION

Patient age had a significant effect on the cellularity of the torn meniscus, with patients older than 40 years having significantly fewer meniscus cells than did those younger than 40 years. Further studies are needed to define the relative importance of the individual histologic findings in the clinical setting of meniscus tear and repair.

CLINICAL RELEVANCE

In light of their decreased cellularity, menisci from patients older than 40 years may be more vulnerable to degeneration and retear after repair than are menisci of younger patients.

Effect of Medial Meniscal Release on Tibial Translation After Tibial Plateau Leveling Osteotomy

OBJECTIVE

To evaluate the biomechanical effects of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on joint stability in the cranial cruciate ligament (CCL)-deficient canine stifle before and after tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

Experimental study.

ANIMALS

Thirty-one dogs.

METHODS

In experiment 1, 16 pairs of normal hindlimbs randomly assigned to an intact or transected CCL group were studied to determine the magnitude of tibial translation after MMR and MCH under 20% body weight load using radiographic imaging of radio-opaque markers. In experiment 2, 15 pairs of CCL-deficient hindlimbs were randomly assigned to a TPLO or sham TPLO group. The remainder of the experiment was performed as described for experiment 1. The effect of CCL transection, MMR, MCH and TPLO were analyzed using 2-way repeated measures ANOVA; P<.05 was considered significant.

RESULTS

We found a greater effect of MMR on tibial translation in transected CCL stifles than in intact stifles (P=.0016). We found no further effect of MCH after MMR (P>.05). We found a greater effect of MMR in sham TPLO than TPLO stifles (P=.0013) but no further effect of MCH after MMR (P>.05).

CONCLUSIONS

By resisting tibial translation the medial meniscus might be at greater risk of tearing in CCL-deficient stifles. TPLO may spare the medial meniscus by neutralizing the tibial thrust and eliminating the wedge effect of the medial meniscus.

CLINICAL RELEVANCE

MMR may not be indicated in the CCL-deficient stifle stabilized by TPLO.

Mechanical properties of articular cartilage covered by the meniscus

OBJECTIVE

To investigate the mechanical properties and morphological characteristics of articular cartilage on the tibial plateau of human knees, including the region covered by the meniscus.

DESIGN

Using a 1-mm diameter flat-ended cylindrical probe to apply a constant load (0.6 MPa) at specific sites on the tibial plateau, the mechanical properties of articular cartilage were studied using seven cadaver knees. Comparison was made between data obtained by the cartilage covered by the meniscus and that not covered. This was done for both the medial and lateral plateaus. Histological sections of the articular cartilage were also performed to study differences between cartilage from these regions of the tibial plateau.

RESULTS

Compared to cartilage that was not covered by the meniscus, the articular cartilage beneath the meniscus showed a significantly (P<0.05) larger modulus by as much as 70%, and was less thick by about 40%. Also, the subchondral bone quantity and calcified layer thickness were observed to be significantly lesser in the regions covered by the meniscus.

CONCLUSIONS

Our findings revealed a significant difference between the mechanical properties and associated structures of articular cartilage in the region covered by the meniscus compared with the articular cartilage not covered by the meniscus.

The relationship between menstrual cycle phase and anterior cruciate ligament injury: a case-control study of recreational alpine skiers

BACKGROUND

Female athletes suffer a greater incidence of anterior cruciate ligament tears compared with male athletes when participating in common sports; however, very little is known about the factors that explain this disparity.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Female recreational alpine skiers with an anterior cruciate ligament rupture and age-matched control skiers provided a serum sample and self-reported menstrual history data immediately after injury. Both serum concentrations of progesterone and menstrual history were then used to group subjects into either preovulatory or postovulatory phases of the menstrual cycle.

RESULTS

Analysis of serum concentrations of progesterone revealed that alpine skiers in the preovulatory phase of the menstrual cycle were significantly more likely to tear their anterior cruciate ligaments than were skiers in the postovulatory phase (odds ratio, 3.22; 95% confidence interval, 1.09-9.52; P = .027). Analysis of menstrual history data found similar results, but the difference was not statistically significant (odds ratio, 2.38; 95% confidence interval, 0.86-6.54; P = .086).

CONCLUSION

The likelihood of sustaining an anterior cruciate ligament injury does not remain constant during the menstrual cycle; instead, the risk of suffering an anterior cruciate ligament disruption is significantly greater during the preovulatory phase of the menstrual cycle compared with the postovulatory phase.

CLINICAL RELEVANCE

Phase of menstrual cycle may be one of the risk factors that influence knee ligament injury among female alpine skiers. The findings from this study should be considered in subsequent studies designed to identify persons at risk for anterior cruciate ligament injury and to develop intervention strategies.

Treatment of anterior cruciate ligament injuries, part I

Anterior cruciate ligament injuries are common among athletes. Although the true natural history remains unclear, anterior cruciate ligament injuries are functionally disabling; they predispose the knee to subsequent injuries and the early onset of osteoarthritis. This article, the first in a 2-part series, was initiated with the use of the PubMed database and a comprehensive search of articles that appeared between January 1994 to the present, using the keywords anterior cruciate ligament. A total of 3810 citations were identified and reviewed to determine the current state of knowledge about the treatment of these injuries. Articles pertaining to the biomechanical behavior of the anterior cruciate ligament, the prevalence of anterior cruciate ligament injury, the natural history of the anterior cruciate ligament-deficient knee, injuries associated with anterior cruciate ligament disruption, risk factors for anterior cruciate ligament injury, indications for treatment of anterior cruciate ligament injuries, and nonoperative and operative treatments were obtained, reviewed, and served as the basis for part I. Part II, to be presented in another issue of this journal, includes technical aspects of anterior cruciate ligament surgery, bone tunnel widening, graft healing, rehabilitation after reconstruction, and the effect of sex, age, and activity level on the outcome of surgery. Our approach was to build on prior reviews and to provide an overview of the literature for each of the before-mentioned areas of study by summarizing the highest level of scientific evidence available. For the areas that required a descriptive approach to research, we focused on the prospective studies that were available; for the areas that required an experimental approach, we focused on the prospective, randomized controlled trials and, when necessary, the highest level of evidence available. We were surprised to learn that considerable advances have been made during the past decade regarding the treatment of this devastating injury.

MR imaging evaluation of the postoperative knee: ligaments, menisci, and articular cartilage

The surgical management of knee injuries has increased in recent years. Postoperative magnetic resonance (MR) imaging of the knee following surgical intervention serves an important role in the diagnostic evaluation of patients with recurrent or residual symptoms following surgical intervention. MR imaging additionally assists in the noninvasive documentation of temporal changes at the surgical site potentially reflective of procedural success, or failure. Background understanding of the common surgical procedures performed, their normal postoperative MR imaging appearance, and imaging features of potential procedural complications are essential in the accurate evaluation of patients following prior knee surgery. The focus of the following article is to review the clinical and MR imaging features of the postoperative knee following prior surgical treatment of ligamentous, meniscal, and articular cartilage injuries of the joint.

Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography

PURPOSE

To prospectively investigate the accuracy of conventional magnetic resonance (MR) imaging, direct MR arthrography, and indirect MR arthrography in assessment of possible recurrent or residual meniscal tears.

MATERIALS AND METHODS

Three hundred sixty-four patients who had previously undergone meniscal preservation surgery were prospectively examined with conventional MR imaging, indirect MR arthrography, and direct MR arthrography. Ninety-four patients (104 postoperative menisci) underwent subsequent second-look arthroscopic surgery. Each case was evaluated for (a) surfacing intrameniscal intermediate- or T1-weighted signal intensity, (b) surfacing intrameniscal T2-weighted signal intensity, (c) morphologic changes beyond those expected postoperatively, (d) joint effusion on conventional MR or indirect MR arthrographic studies, and (e) overall presence or absence of recurrent meniscal tear.

RESULTS

Seventy-one arthroscopically proved recurrent meniscal tears were found. In the diagnosis of recurrent meniscal tears, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 86%, 67%, 83%, 71%, and 80%, respectively, for conventional MR imaging; 83%, 78%, 90%, 64%, and 81%, respectively, for indirect MR arthrography; and 90%, 78%, 90%, 78%, and 85%, respectively, for direct MR arthrography. No significant difference in the diagnostic accuracy of one method relative to another was observed (P >.54). Surfacing intrameniscal T2-weighted signal intensity was the most specific sign, with the highest positive predictive value of a recurrent tear.

CONCLUSION

Although a small incremental increase in accuracy is associated with the use of direct MR arthrography over conventional MR imaging and indirect MR arthrography, no significant difference in diagnostic accuracy among the three techniques was demonstrated for detection of recurrent or residual meniscal tear.

Eighteen- to twenty-five-year follow-up after acute partial anterior cruciate ligament rupture

Of 22 consecutive patients with minor knee instability after a partial rupture of the anterior cruciate ligament, all could be reexamined after a mean of 12 years and all but 1 could be reexamined after a mean of 20 years. Three patients needed surgery during the follow-up period, but nobody had an anterior cruciate ligament reconstruction. The Lysholm knee function score was excellent and did not change between 12 and 20 years. Patients had decreased their activities from contact sports before injury to physical fitness activities at the late follow-up. Four patients changed activities because of a knee problem. The quality of life score was somewhat higher than may be expected in an age-matched average population. At late follow-up, eight patients had a 1+ Lachman sign, two a 2+ Lachman sign, and one a positive pivot shift. Also at late follow-up, 7 knees showed no signs of radiographic osteoarthrosis, 10 had Fairbank's signs, and 3 had minor and 1 a major joint space reduction. Of the 12 patients with longitudinal radiographic observation, 3 knees had developed a higher degree of osteoarthrosis, and 9 had remained unchanged. The patients had a mean age of 48 years at the late follow-up. This suggests that the results may be regarded as final outcome after this specific knee injury.

Function of the normal meniscus and consequences of meniscal resection

The principal functions of the meniscus are load transmission and shock absorption, based on the meniscal collagen architecture, the biochemical fluid composition, and the proteoglucan-collagen meshwork. The mobile menisci transmit 50-90% of load over the knee joint, depending on knee flexion angle, femoral translation and rotation. The meniscus contributes to knee joint proprioception and probably also to joint stability. Late consequences of total and partial meniscectomy are radiographic osteoarthritis, with a varying percentage of these patients having symptoms. Malalignment, concomitant articular cartilage lesions, and ligament instability are absolute risk factors, while age, lateral compartment, and continued sport activity are relative risk factors. Acute reinsertion of meniscal tears in the red-red or red-white zones can be performed successfully by arthroscopic technique. Also in chronic tears stable healing can be expected in most cases, if the scar tissue is resected.

Open meniscal repair: clinical and magnetic resonance imaging findings after twelve years

The purpose of this study was to document the longterm clinical, radiographic, and magnetic resonance imaging results after open meniscal repair. Twenty-two patients, with 23 open meniscal repairs, were evaluated after a mean follow-up of 12.9 years using patient history, physical examination, KT-1000 arthrometer testing, the "Orthopaedische Arbeitsgemeinschaft Knie" knee evaluation scheme, Tegner activity score, weightbearing radiographs, and magnetic resonance imaging. Two of the 22 patients had retears and both occurred in unstable knees. Radiographs revealed no degenerative changes in 17 of the 23 compartments. Grade III and IV signal alterations were present on magnetic resonance imaging scans in more than 50% of the repaired menisci. We concluded that the longterm survival rate of repaired menisci was 91%, and that magnetic resonance imaging is unsuitable for diagnosis of the healing process of a repaired meniscus.

Different regional healing rates with the outside-in technique for meniscal repair

Fifty-one patients with meniscal repair using the outside-in technique were reassessed with second-look arthroscopic procedures (N = 15), arthrographic examination (N = 41), magnetic resonance imaging (N = 36), or a combination of these techniques. Forty-one medial and 10 lateral menisci were repaired. The average clinical follow-up was 15 months (range, 3 to 80). Forty-five of 51 patients had tears that were located in or extended into the posterior horn of the medial or lateral meniscus. Complete healing occurred in 23 menisci (45%), partial healing was observed in 16 (15 medial, 1 lateral) (32%), and no healing occurred in 12 (24%). Remarkably, in all 15 patients who had tears extending from the posterior to the middle third of the medial meniscus that were partially healed, it was always the posterior third that had not fully healed. This finding is statistically significant. In addition, the middle third of these menisci had not fully healed in five patients. No healing occurred in the two patients with tears in the posterior third of the medial meniscus. Poor healing with the outside-in technique was observed in patients with tears into the posterior horn of the medial meniscus. For tears in the middle and anterior portion of the medial meniscus, as well as all lateral meniscus tears, the outside-in technique is our current method of choice.

Ten-year prognosis of isolated and combined medial collateral ligament ruptures. A matched comparison in 40 patients using clinical and radiographic evaluations

In a matched-pair study of 40 patients, the prognoses of patients with acute isolated partial medial collateral ligament injuries and acute combined medial collateral and anterior cruciate ligament injuries were compared 10 years after initial treatment. All patients in the first group were treated nonoperatively. In the latter group, most medial collateral ligament injuries were total ruptures, which were thoroughly repaired; the torn anterior cruciate ligament was repaired with augmentation in half of the cases. At the follow-up evaluation, both patient groups had similarly high knee functions according to the Lysholm score and similar activity levels (recreational team sports). Knees with combined injuries had increased sagittal laxity at manual and instrumented assessment. Radiographic signs of knee osteoarthritis were present in half of the knees with combined injuries, but they were absent in knees with isolated injuries. The long-term functional prognosis was similarly good after isolated or combined medial collateral ligament injuries, but patients with combined ruptures had more reinjuries and repeat surgeries, increased sagittal laxity, and a higher incidence of radiographic osteoarthritis.

The long-term prognosis for severe damage to weight-bearing cartilage in the knee: a 14-year clinical and radiographic follow-up in 28 young athletes

We examined 28 young athletes with isolated severe chondral damage in the weight-bearing area of the knee joint clinically and radiographically 14 years after arthroscopic diagnosis. Except for Pridie drilling in 3 cases and occasional cartilage shaving or removal of free bodies, no special treatment was given initially. 21 patients were able to return to preinjury team sport activity levels. During the follow-up period, only 3 patients needed repeat surgery with removal of free bodies, and another 2 underwent diagnostic arthroscopy because of persistent pain. At the latest follow-up evaluation, 22 patients had excellent or good knee function. At this time, the patients were mainly involved in individual sports on a physical fitness level. 12 cases had radiographic joint space reduction (< 50%) which was limited to the compartment concerned.

Long-term prognosis of isolated partial medial collateral ligament ruptures. A ten-year clinical and radiographic evaluation of a prospectively observed group of patients

We prospectively observed 38 patients with nonoperatively treated isolated partial ruptures of the knee medial collateral ligament at 3 months, 4 years, and 10 years after the initial trauma using clinical and radiographic examinations. The initial diagnoses were based on clinical and arthroscopic examinations. Three months after injury, 28 patients (74%) had regained nearly normal knee function and muscle strength, and 75% of these patients could perform at their preinjury activity level (competitive team sports). Five patients (13%) had increased valgus laxity (grade 1) in the injured knee. After 4 years, the patients had a median Lysholm score of 100 (range, 64 to 100). Thirty-three patients (87%) had normal knee function during strenuous activities. Repeat injuries to the medial collateral ligament occurred in two patients (5%), and another two patients sustained cruciate ligament injuries during the follow-up period. After 10 years, the Lysholm score (median, 95; range, 73 to 100) was lower compared with the 4-year score (P < 0.03), but the patients still performed on a similarly high activity level. Five patients (13%) had distinct signs of beginning osteoarthritis (Fairbank's signs) on radiographs, but none had joint space reduction.

Knee ligament injury, surgery and osteoarthrosis. Truth or consequences?

We reviewed reports that describe development of osteoarthrosis of the knee after anterior cruciate ligament or meniscus injury. The occurrence of posttraumatic osteoarthrosis varied considerably from one report to another. The literature does not lend support to the efficacy of cruciate ligament repair or reconstruction in retarding the progression of osteoarthrosis after knee injury. We encourage prospective, controlled, randomized and masked studies that aim to evaluate the utility of ligament reconstruction, meniscus suture or meniscus transplantation for preventing posttraumatic osteoarthrosis.

The prevalence of gonarthrosis and its relation to meniscectomy in former soccer players

The prevalence of radiographic signs of gonarthrosis and its relation to knee injuries were studied in 286 former soccer players--215 nonelite and 71 elite players--and were compared with 572 age-matched controls with a mean age of 55 years. The prevalence of gonarthrosis among the nonelite players was 4.2%, among the elite players 15.5%, and among the controls 1.6%. Seven of the soccer players had known anterior cruciate ligament injuries, and 40 had had meniscectomies. Of the 32 nonelite players with knee injuries, 4 (13%) had gonarthrosis, and of the 183 without known knee injuries 5 (3%) had gonarthrosis. Among the elite players, the prevalence of gonarthrosis in knees without diagnosed injuries was 11%. We conclude that soccer, especially at an advanced level, is associated with an increased risk for gonarthrosis. After excluding subjects with known knee injuries, there was no difference between nonelite players and controls, but we found a higher rate of gonarthrosis among the elite players.

Temporal patterns of stromelysin-1, tissue inhibitor, and proteoglycan fragments in human knee joint fluid after injury to the cruciate ligament or meniscus

Stromelysin-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and proteoglycan fragments were quantified in knee synovial fluid samples in a cross-sectional study of patients who had injury to the anterior cruciate ligament or the meniscus. The average concentrations of stromelysin-1 and TIMP-1 increased 25-fold and 10-fold within the first day after the trauma, respectively, and the concentration of proteoglycan fragments increased 4-fold. From approximately 1-6 months after injury, the levels of these markers were higher after injury to the cruciate ligament than after injury to the meniscus. From 6 months to 18 years after trauma, however, the levels of stromelysin-1 and TIMP-1 in patients who had an injury to the ligament were the same as the levels in patients who had a meniscal lesion, but the levels were increased compared with those for a reference group of healthy volunteers. The molar balance of stromelysin-1 to TIMP-1 in synovial fluid in both groups of injured joints changed from a balance representing an excess of free inhibitor in the normal joint to one representing an excess of free enzyme in the injured joint. The increased release of these markers to joint fluid both early and late after trauma may be caused by a change in the loading patterns in the knee with an injured ligament or meniscus or by synovitis induced by bleeding. The increased release may be associated with the frequent development of posttraumatic osteoarthritis in patients with these injuries.

Effects of meniscectomy and anterior cruciate ligament transection on rabbit knee joint in-vitro mechanics and cartilage gross morphology

The effects of meniscectomy and anterior cruciate ligament transection on knee joint compression compliance, capacity of energy storage and cartilage gross morphology were studied in rabbits six and 12 weeks postoperatively. Joints with meniscectomy and intact ligaments at 12 weeks had a similar joint compression compliance as sham-operated joints with intact menisci, but had moderate unicompartmental osteoarthritis. Further, the capacity of energy storage of such a joint was reduced. Knees with anterior cruciate ligament transection had a higher joint compression compliance than knees with intact joint structures. Anterior cruciate ligament transection caused severe cartilage degeneration of both knee compartments at 6 weeks, but in knees with intact menisci the tibial cartilage was better preserved than in knees with meniscectomy. Synovitis was pronounced in anterior cruciate ligament transected knees. In conclusion, meniscectomy reduced the capacity of energy storage of the joint and was followed by moderate unicompartmental cartilage degeneration at 12 weeks. Anterior cruciate ligament transection especially when combined with meniscectomy led during a similar observation period to more dramatic effects on joint compression compliance and morphology.

Arthroscopic repair of the bucket-handle meniscus. 10 failures in 27 stable knees followed for 3 years

In a total of 535 meniscal lesions diagnosed by arthroscopy, 54 patients had their meniscus sutured arthroscopically. 25 cases were excluded from the study due to concomitant ligamentous injury, while 2 were lost to follow-up, leaving 27 cases of arthroscopic repair of isolated bucket-handle meniscal tears for review. 8 cases had the repaired meniscus partially resected later due to recurring symptoms. The remaining 19 cases were scored for knee function and activity after a median observation time of 36 (18-52) months. 15 of 19 patients with a supposedly healed meniscus had normal knee function, i.e., unchanged compared to preinjury levels, but a slight drop in median activity score. With 8 re-ruptures and 2 patients who stated result as poor, the 10/27 failure rate was rather high. Our results are not as good as most reported previously.

The effect of a meniscal prosthesis on knee biomechanics and cartilage. An experimental study in rabbits

A meniscal prosthesis made of Dacron with polyurethane coating was tested as a substitute for the medial meniscus in a rabbit experimental model concentrating on biomechanical behavior of the knee joint and gross and histologic evaluation 3 months after surgery. The results were compared to sham-operated knees, knees with a peripheral incision of the medial meniscus, and knees with a total meniscectomy. Knees with prosthesis implantation had the same stiffness as knees with sham-operation or meniscal incision, but knees with meniscectomy were stiffer (P less than 0.05). Knees with prosthesis showed lower energy storage during relaxation than knees with sham-operation or meniscal incision (P less than 0.05). Energy storage in the prosthesis group was similar to the meniscectomy group. Partial or total ingrowth of synovial tissue into the prosthesis was present in 93%, and 63% of the incised menisci had healed. Cartilage changes were present in 70% of the prosthesis group, in 25% of the knees with meniscal incision, and in all knees with meniscectomy. The sham-operated knees were free from cartilage degeneration. Knees with prosthesis had the same frequency of cartilage changes on the femur, but had less changes on the tibia compared to knees with meniscectomy. A high rate of osteophyte formation was observed after prosthesis implantation as well as following meniscectomy, but the osteophytes were larger in the prosthesis group (P less than 0.01). The most frequent and severe effect on the synovium was found in the prosthesis group (92%), but no foreign body reaction or loose Dacron particles were found.(ABSTRACT TRUNCATED AT 250 WORDS)

The long-term course after treatment of acute anterior cruciate ligament ruptures. A 9 to 16 year followup

Acute total ACL (N = 60) and concomitant medial collateral ligament (N = 46) ruptures were repaired in 60 patients (mean age, 28 years) without augmentation. Menisci were removed in 23 knees. Fifty-three (88%) of the patients were reexamined 9 to 16 years later with special emphasis on manual and instrumented stability testing (Stryker, Genucom), knee function score (Lysholm), and activity level (Tegner). Standing roentgenograms (30 degrees of knee flexion) were taken in 69% of the patients. At followup, an ACL reconstruction had been performed in seven patients (12%) due to symptomatic instability. Sixty-four percent of the knees had a positive Lachman sign and 40% a positive pivot shift. Sagittal laxity difference was +3 mm or more in 57%. Knee function score was a mean of 86 +/- 12 points. The mean activity level had changed from recreational team sports (Level 7) to recreational individual sports (Level 5). Only patients with good knee stability were able to perform demanding sports and could continue at their desired activity level. Osteoarthritis of slight to moderate degree (Fairbank I/II) was found in 58% of the patients younger than 35 years of age at the time of trauma and in 87% of the older patients. Knees with intact menisci had less osteoarthritis than knees with removed menisci (P less than 0.05).